Environmental Research

About the journal

Publisher: Elsevier
Published: 1967 to the present, Netherlands
Language: English
ISSN: 0013-9351 (print), 1096-0953 (electronic)
Its record in the NLM Catalog

2020s

In vitro cyto- and geno-toxicity of asbestiform erionite from New Zealand. S. Scarfì, V. Almonti, S. Mirata, et al. 2025;265:120415. PubMed · Publisher

Abstract

This work is an in vitro toxicity study of two asbestiform erionites from Kaipara and Gawler Downs in New Zealand. This study is the first, to the knowledge of the authors, to investigate the mechanisms that trigger adverse effects leading to carcinogenicity from New Zealand erionites. The effects induced by the erionite fibres from New Zealand were compared with those produced by positive (crocidolite) and negative (wollastonite) standards, and other erionite fibres described in the literature. The cytotoxicity/genotoxicity/inflammatory potential was determined by: (i) analysis of the cytotoxic potential by MTT tests on human cell lines mimicking primary cells making direct contact with fibres in the lungs, combined with apoptosis tests and cell membrane damage by fluorescence microscopy analyses; (ii) analysis of the genotoxic potential by quantification of DNA damage measuring double strand break foci by γ-H2AX nuclear staining in confocal microscopy analyses; (iii) analyses of the acute (24-72h) and early-chronic (7d) inflammatory effect by gene expression analyses of several cytokines, as well as of fibrotic and Epithelial to Mesenchymal transition (EMT) markers. The intensity of cell responses to these erionites are comparable to that of standard carcinogenic crocidolite, indicating that the two erionite fibres exhibit a significant acute toxic potential, with a particular alarming effect from the Gawler Downs sample from South Island. Our results confirm that the investigated erionites from New Zealand may represent an environmental hazard. However, further investigation is required to determine potential environmental exposure pathways by which erionite may become airborne and assess any environmental risks that may arise.

Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.
Response to the editor-Environmental Research this letter is a critique of the paper by Roggli et al. (1) regarding chronological trends of the fiber burden in mesothelioma cases. V.L. Roggli, E.N. Pavlisko, C.H. Glass, et al. 2024;251(Pt 1):118620. Letter · Comment PubMed · Publisher
To the Editor-environmental research this letter is a critique of the paper by regarding chronological trends of the fiber burden in mesothelioma cases. A.L. Frank. 2024;251(Pt 1):117352. Letter · Comment PubMed · Publisher
An updated review of diffuse mesothelioma of the pleura - A sentinel health event of potential elongate mineral particle pathogenicity. S.R. Smith. 2023;230:115608. Review PubMed · Publisher

Abstract

There are approximately 400 inorganic minerals in the Earth's crust, some of which can be encountered as elongate mineral particles [EMPs] with dimensional characteristics similar to the six minerals known as asbestos and other asbestiform amphiboles with established human pathogenicity. In addition, the rapidly developing field of nanotechnology is producing an ever-increasing array of high aspect ratio engineered nanomaterials [HARNs] with physical dimensions and biodurability similar to the asbestos fiber types with recognized pathogenic potential. Many of these non-asbestos/non-asbestiform EMPs and HARNs with the potential for aerosolization into the breathing zones of workers and in individuals in non-occupational environments have not yet been thoroughly studied with respect to their potential human pathogenicity, a fact which obviously poses concerns for both occupational health and public health professionals. On the basis of dose-response considerations it seems reasonable to infer that if any of these non-regulated EMPs or HARNs actually are pathogenic, then those mineral fiber exposure-induced disorders associated with the lowest cumulative exposure doses of the commercial amphibole types of asbestos, that is, diffuse mesothelioma of the pleura, and its non-malignant correlate of benign parietal pleural plaques, are those which are most likely to occur following inhalational exposures to any of the non-regulated EMPs and HARNs. Because of that observation, this paper reviews certain aspects of diffuse mesothelioma, including a summary of recent changes in the nomenclature of diffuse mesothelioma of the pleura; of both the descriptive and the analytical epidemiology of the disease; of the etiologies of mesothelioma, both "exposure" related and endogenous in nature; and of the asbestos population attributable fraction for diffuse mesotheliomas in the USA, both historically and in the future.

Copyright © 2023 Elsevier Inc. All rights reserved.
Asbestiform fibers and cleavage Fragments: Conceptual approaches for differentiation in laboratory practice and data analysis. E.J. Chatfield. 2023;230:114529. PubMed · Publisher

Abstract

The respirable fractions from 46 different crushed amphibole samples were separated by water elutriation. The dimensions of approximately 200 elongate mineral particles (EMPs) longer than 5 μm in each of these fractions were measured by transmission electron microscopy (TEM). The data were used to address three questions: 1. Can amphiboles be classified on a scale that represents the level of inhalation hazard they present? 2. Can prismatic amphibole be discriminated from amphibole asbestos on the basis of EMP size distributions and concentration measurements? 3. How do different exposure indices (Phase Contrast Microscopy Equivalent (PCME), Berman & Crump protocol fibers, Chatfield extra-criteria EMPs) compare when applied to these amphibole samples? For each sample, the number of respirable EMPs longer than 5 μm per gram of respirable dust and the number of extra-criteria EMPs per gram of respirable dust were calculated. The number of respirable EMPs longer than 5 μm per gram of respirable dust and the proportion of those with dimensions associated with mesothelioma in animal studies were considered to be contributors to the inhalation hazard presented by amphibole dust. In addition to these concentration measurements, the median EMP width, median aspect ratio and the aspect ratio geometric standard deviation (GSD) were considered to be relevant parameters in discriminating prismatic amphibole from asbestiform amphibole. A plot of the aspect ratio GSD against either the concentration of respirable EMPs per gram of respirable dust, the median aspect ratio or the median width allowed discrimination. The data showed a close correspondence between exposures in terms of Chatfield extra-criteria EMPs and Berman and Crump protocol structures for all of the amphibole samples. However, although for commercial asbestos varieties exposures in terms of PCME fibers were comparable to those of the other two metrics, they greatly exceeded those for non-asbestiform amphiboles.

Copyright © 2022 Elsevier Inc. All rights reserved.
Carbon nanotube pathogenicity conforms to a unified theory for mesothelioma causation by elongate materials and fibers. A. Nel. 2023;230:114580. Review PubMed · Publisher

Abstract

The purpose of this review is to elucidate how dimensional and durability characteristics of high aspect ratio nanomaterials (HARN), including carbon nanotubes (CNT) and metal nanowires (MeNW), contribute to understanding the fiber pathogenicity paradigm (FPP), including by explaining the structure-activity relationships (SAR) of a diverse range of natural and synthetic elongate materials that may or may not contribute to mesothelioma development in the lung. While the FPP was originally developed to explain the critical importance of asbestos and synthetic vitreous fiber length, width, aspect ratio and biopersistence in mesothelioma development, there are a vast number of additional inhalable materials that need to be considered in terms of pathogenic features that may contribute to mesothelioma or lack thereof. Not only does the ability to exert more exact control over the length and biopersistence of HARNs confirm the tenets of the FPP, but could be studied by implementating more appropriate toxicological tools for SAR analysis. This includes experimentation with carefully assembled libraries of CNTs and MeNWs, helping to establish more precise dimensional features for interfering in lymphatic drainage from the parietal pleura, triggering of lysosomal damage, frustrated phagocytosis and generation of chronic inflammation. The evidence includes data that long and rigid, but not short and flexible multi-wall CNTs are capable of generating mesotheliomas in rodents based on an adverse outcome pathway requiring access to pleural cavity, obstruction of pleural stomata, chronic inflammation and transformation of mesothelial cells. In addition to durability and dimensional characteristics, bending stiffness of CNTs is a critical factor in determining the shape and rigidity of pathogenic MWCNTs. While no evidence has been obtained in humans that CNT exposure leads to a mesothelioma outcome, it is important to monitor exposure levels and health effect impacts in workers to prevent adverse health outcomes in humans.

Copyright © 2022 The Author. Published by Elsevier Inc. All rights reserved.
Characterization of elongate mineral particles including talc, amphiboles, and biopyriboles observed in mineral derived powders: Comparisons of analysis of the same talcum powder samples by two laboratories. M.S. Sanchez, M. McGrath-Koerner, B.D. McNamee. 2023;230:114791. PubMed · Publisher

Abstract

Elongate mineral particles, including asbestos, have long been screened in talc and other mineral powders. In recent years, there has been a renewed scrutiny of talc containing asbestos due to allegations in civil litigation in the United States as well as reports, proposals, and white papers by international laboratories and government bodies related to this subject. This study demonstrates the importance of the fundamental understanding of both mineralogy and its application, using microscopy with empirical examples from conflicting analyses of the same talc powders by two independent laboratories in civil litigation in the United States. Methods include polarized light microscopy (PLM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) in the accurate measurement of morphological, optical, compositional, and structural data to characterize mineral-based samples. Discussions in this study include: 1) contrasting the interlaboratory findings of amphibole and amphibole asbestos by PLM and TEM using various preparation techniques, 2) the use of multiple analytical tools on a singular particle for identification, 3) the misidentification of anthophyllite asbestos by inexpert use of electron diffraction using TEM, and 4) the misidentification of chrysotile in talc by PLM. These examples emphasize the importance of not only maintaining the existing requirements, but of the need for even more rigorous analytical requirements in routine monitoring of elongate mineral particles that may occur in mineral-based powders.

Copyright © 2022. Published by Elsevier Inc.
Chronological trends in the causation of malignant mesothelioma: Fiber burden analysis of 619 cases over four decades. V.L. Roggl, C.L. Green, B. Liu, et al. 2023;230:114530. PubMed · Publisher · Free full text

Abstract

Malignant mesothelioma is a relatively rare malignancy with a strong association with prior asbestos exposure. A percentage of cases is not related to asbestos, and fiber analysis of lung tissue is a useful methodology for identifying idiopathic or spontaneous cases. We have performed fiber analyses in more than 600 cases of mesothelioma over the past four decades and were interested in looking for trends in terms of fiber types and concentrations as well as percentages of cases not related to asbestos. Demographic information was also considered including patient age, gender, and tumor location (pleural vs. peritoneal). The histologic pattern of the tumor and the presence or absence of pleural plaques or asbestosis were noted. Fiber analysis was performed in 619 cases, using the sodium hypochlorite technique for digestion of lung tissue samples. Asbestos bodies were counted by light microscopy (LM) and coated and uncoated fibers by scanning electron microscopy (EM). The results were stratified over four decades. Trends that were observed included increasing patient age, increasing percentage of women, increasing percentage of peritoneal cases, and increasing percentage of epithelial histological type. There was a decreasing trend in the percentage of patients with concomitant asbestosis (p < 0.001). The percentage of cases with an elevated lung asbestos content decreased from 90.5% in the 1980s to 54.1% in the 2010s (p < 0.001). This trend also held when the analysis was limited to 490 cases of pleural mesothelioma in men (91.8% in the 1980s vs. 65.1% in the 2010s). There was a decrease in the median asbestos body count by LM from 1390 asbestos bodies per gram of wet lung in the 1980s to 38 AB/gm in the 2010s. Similar trends were observed for each of the asbestos fiber types as detected by EM. We conclude that there has been a progressive decrease in lung fiber content of mesothelioma patients during the past four decades, with an increasing percentage of cases not related to asbestos and an increase in median patient age.

Copyright © 2022 Elsevier Inc. All rights reserved.
Cytotoxicity of fibrous antigorite from New Caledonia. E. Gazzano, J.R. Petriglieri, E. Aldieri, et al. 2023;230:115046. PubMed · Publisher

Abstract

Exposure to asbestos and asbestos-like minerals has been related to the development of severe lung diseases, including cancer and malignant mesothelioma (MM). A high incidence of non-occupational MM was observed in New Caledonia (France) in people living in proximity of serpentinite outcrops, containing chrysotile and fibrous antigorite. Antigorite is a magnesium silicate, which shares with chrysotile asbestos the chemical formula. To achieve information on antigorite toxicity, we investigated the physico-minero-chemical features relevant for toxicity and cellular effects elicited on murine macrophages (MH-S) and alveolar epithelial cells (A549) of three fibrous antigorites (f-Atg) collected in a Caledonian nickel lateritic ore and subjected to supergene alteration. Field Atg were milled to obtain samples suitable for toxicological studies with a similar particle size distribution. UICC chrysotile (Ctl) and a non-fibrous antigorite (nf-Atg) were used as reference minerals. A high variability in toxicity was observed depending on shape, chemical alteration, and surface reactivity. The antigorites shared with Ctl a similar surface area (16.3, 12.1, 20.3, 13.4, and 15.6 m2/g for f-Atg1, 2, 3, nf-Atg, and Ctl). f-Atg showed different level of pedogenetic weathering (Ni depletion f-Atg1 ≪ f-Atg2 and 3) and contained about 50% of elongated mineral particles, some of which exhibited high aspect ratios (AR > 10 μm, 20%, 26%, 31% for f-Atg1, 2, and 3, respectively). The minerals differed in bio-accessible iron at pH 4.5 (f-Atg1 ≪ f-Atg3, < f-Atg2, nf-Atg < Ctl), and surface reactivity (ROS release in solution, f-Atg1 ≪ f-Atg2, 3, nf-Atg, and Ctl). f-Atg2 and f-Atg3 induced oxidative stress and pro-inflammatory responses, while the less altered, poorly reactive sample (f-Atg1) induced negligible effects, as well nf-Atg. The slow dissolution kinetics observed in simulated body fluids may signal a high biopersistence. Overall, our work revealed a significative cellular toxicity of f-Atg that correlates with fibrous habit and surface reactivity.

Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.
Dimensions of elongate mineral particles and cancer: A review. A.G. Wylie, A.A. Korchevskiy. 2023;230:114688. Review PubMed · Publisher

Abstract

Context: Based on a decade-long exploration, dimensions of elongate mineral particles are implicated as a pivotal component of their carcinogenic potency. This paper summarizes current understanding of the discovered relationships and their importance to the protection of public health.

Objectives: To demonstrate the relationships between cancer risk and dimensions (length, width, and other derivative characteristics) of mineral fibers by comparing the results and conclusions of previously published studies with newly published information.

Methods: A database including 59 datasets comprising 341,949 records were utilized to characterize dimensions of elongate particles. The descriptive statistics, correlation and regression analysis, combined with Monte Carlo simulation, were used to select dimensional characteristics most relevant for mesothelioma and lung cancer risk prediction.

Results: The highest correlation between mesothelioma potency factor and weight fraction of size categories is achieved for fibers with lengths >5.6 μm and widths ≤0.26 μm (R = 0.94, P < 0.02); no statistically significant potency was found for lengths <5 μm. These results are consistent with early published estimations, though are derived from a different approach. For combinations of amphiboles and chrysotile (with a consideration of a correction factor between mineral classes), the potency factors correlated most highly with a fraction of fibers longer than 5 μm and thinner than 0.2 μm for mesothelioma, and longer than 5 μm and thinner than 0.3 μm for lung cancer. Because the proportion of long, thin particles in asbestiform vs. non-asbestiform dusts is higher, the cancer potencies of the former are predicted at a significantly higher level. The analysis of particle dimensionality in human lung burden demonstrates positive selection for thinner fibers (especially for amosite and crocidolite) and prevailing fraction of asbestiform habit.

Conclusion: Dimensions of mineral fibers can be confirmed as one of the main drivers of their carcinogenicity. The width of fibers emerges as a primary potency predictor, and fibers of all widths with lengths shorter than 5 μm seem to be non-impactful for cancer risk. The mineral dust with a fibrous component is primarily carcinogenic if it contains amphibole fibers longer than 5 μm and thinner than 0.25 μm.

Copyright © 2022 Elsevier Inc. All rights reserved.
Discriminant analysis of amphiboles: Additional considerations. D.R. Van Orden. 2023;230:114579. PubMed · Publisher

Abstract

Amphibole minerals are found throughout nature and could pose a respiratory hazard if these exist in the asbestiform growth habit. Though amphibole asbestos has not been used in commercial products as an added material for more than 30 years, these minerals could exist in other materials as trace contaminants as well as occurring in mines and earth-moving environments. It is necessary, then, that the asbestiform amphibole minerals be properly identified in order to appropriately use health-protective measures. Recent analyses of various amphibole data sets have been used to derive a discriminant function that can be used to differentiate asbestiform amphibole from non-asbestiform amphibole minerals. This paper expands on this function and examines the validity of the procedure for different size fractions of minerals. This analysis suggests that the derived function is appropriate for fibers 10 μm and longer. For fibers shorter than 10 μm, the data suggest that a broader acceptance limit may be needed. The data also suggest that current analytical procedures may require some adjustment to provide more accurate details on the widths of fibers. With additional samples, the accuracy of the discriminate function can be improved by calculating functions for each mineral.

Copyright © 2022 Elsevier Inc. All rights reserved.
Epidemiologic roadblocks in studying elongated mineral particles and mesothelioma risk. W. Lieberman-Cribbin, E. Taioli. 2023;230:115086. PubMed · Publisher

Abstract

Elongated mineral particles (EMPs) are a type of both occupational and environmental exposures that have generated interest in the scientific community due to their potential health effects. Their possible association with mesothelioma represents an area of concern. We provide an overview of the current challenges around epidemiological assessments of EMP exposure and mesothelioma risk, including methodological aspects that need to be addressed when designing and analyzing a study on EMP exposure and mesothelioma. Future work is needed to investigate the relationship between EMPs and mesothelioma, focused on an improved definition of EMP exposure and accounting for other concomitant sources of carcinogen exposure.

Copyright © 2022 Elsevier Inc. All rights reserved.
Industry, occupation, and exposure history of mesothelioma patients in the U.S. National Mesothelioma Virtual Bank, 2006-2022. Y. Gao, J.M. Mazurek, Y. Li, et al. 2023;230:115085. PubMed · Publisher · Free full text

Abstract

Background: Malignant mesothelioma is associated with environmental and occupational exposure to certain mineral fibers, especially asbestos. This study aims to examine work histories of mesothelioma patients and their survival time.

Method: Using the NIOSH Industry and Occupation Computerized Coding System, we mapped occupations and industries recorded for 748 of 1444 patients in the U.S. National Mesothelioma Virtual Bank (NMVB) during the period 2006-2022. Descriptive and survival analyses were conducted.

Results: Among the 1023 industries recorded for those having mesothelioma, the most frequent cases were found for those in manufacturing (n = 225, 22.0%), construction (138, 13.5%), and education services (66, 6.5%); among the 924 occupation records, the most frequent cases were found for those in construction and extraction (174, 18.8%), production (145, 15.7%), and management (84, 9.1%). Males (583) or persons aged >40 years (658) at the time of diagnosis tended to have worked in industries traditionally associated with mesothelioma (e.g., construction), while females (163) or persons aged 20-40 years (27) tended to have worked in industries not traditionally associated with mesothelioma (e.g., health care). Asbestos, unknown substances, and chemical solvents were the most frequently reported exposure, with females most often reporting an unknown substance. A multi-variable Cox Hazard Regression analysis showed that significant prognostic factors associated with decreased survival in mesothelioma cases are sex (male) and work experience in utility-related industry, while factor associated with increased survival are epithelial or epithelioid histological type, prior history of surgery and immunotherapy, and industry experience in accommodation and food services.

Conclusion: The NMVB has the potential of serving as a sentinel surveillance mechanism for identifying industries and occupations not traditionally associated with mesothelioma. Results indicate the importance of considering all potential sources of asbestos exposures including occupational, environmental, and extra-occupational exposures when evaluating mesothelioma patients and advising family members.

Copyright © 2022 Elsevier Inc. All rights reserved.
Mechanisms and shapes of causal exposure-response functions for asbestos in mesotheliomas and lung cancers. L.A. Cox, K.T. Bogen, R. Conolly, et al. 2023;230:115607. PubMed · Publisher

Abstract

This paper summarizes recent insights into causal biological mechanisms underlying the carcinogenicity of asbestos. It addresses their implications for the shapes of exposure-response curves and considers recent epidemiologic trends in malignant mesotheliomas (MMs) and lung fiber burden studies. Since the commercial amphiboles crocidolite and amosite pose the highest risk of MMs and contain high levels of iron, endogenous and exogenous pathways of iron injury and repair are discussed. Some practical implications of recent developments are that: (1) Asbestos-cancer exposure-response relationships should be expected to have non-zero background rates; (2) Evidence from inflammation biology and other sources suggests that there are exposure concentration thresholds below which exposures do not increase inflammasome-mediated inflammation or resulting inflammation-mediated cancer risks above background risk rates; and (3) The size of the suggested exposure concentration threshold depends on both the detailed time patterns of exposure on a time scale of hours to days and also on the composition of asbestos fibers in terms of their physiochemical properties. These conclusions are supported by complementary strands of evidence including biomathematical modeling, cell biology and biochemistry of asbestos-cell interactions in vitro and in vivo, lung fiber burden analyses and epidemiology showing trends in human exposures and MM rates.

Copyright © 2023 Elsevier Inc. All rights reserved.
Multistage carcinogenesis: Impact of age, genetic, and environmental factors on the incidence of malignant mesothelioma. S. Moolgavkar, E.T. Chang, E.G. Luebeck. 2023;230:114582. PubMed · Publisher

Abstract

The current paradigm of carcinogenesis as a cellular evolutionary process driven by mutations of a few critical driver genes has immediate logical implications for the epidemiology of cancer. These include the impact of age on cancer risk, the role played by inherited tumor predisposition syndromes, and the interaction of genetics and environmental exposures on cancer risk. In this paper, we explore the following logical epidemiological consequences of carcinogenesis as a clonal process of mutation accumulation, with special emphasis on asbestos-related cancers, specifically malignant mesothelioma:1 All cancers, including mesothelioma, can and do occur spontaneously, i.e., in the absence of exposure to any environmental carcinogens. 2. Age is an important determinant of cancer risk, with or without exposure to environmental carcinogens. 3. Genetic tumor predisposition syndromes, such as the BAP1 syndrome, increase enormously the risk of cancer even in the absence of exposure to environmental carcinogens. We illustrate these concepts by applying a multistage clonal expansion model to U.S. Surveillance, Epidemiology, and End Results cancer registry data for pleural and peritoneal malignant mesotheliomas in 1975-2018.

Copyright © 2022 Elsevier Inc. All rights reserved.
Non-asbestiform elongate mineral particles and mesothelioma risk: Human and experimental evidence. J.E. Goodman, M.J. Becich, D.M. Bernstein, et al. 2023;230:114578. PubMed · Publisher · Free full text

Abstract

The presentations in this session of the Monticello II conference were aimed at summarizing what is known about asbestiform and non-asbestiform elongate mineral particles (EMPs) and mesothelioma risks based on evidence from experimental and epidemiology studies. Dr. Case discussed case reports of mesothelioma over the last several decades. Dr. Taioli indicated that the epidemiology evidence concerning non-asbestiform EMPs is weak or lacking, and that progress would be limited unless mesothelioma registries are established. One exception discussed is that of taconite miners, who are exposed to grunerite. Drs. Mandel and Odo noted that studies of taconite miners in Minnesota have revealed an excess rate of mesothelioma, but the role of non-asbestiform EMPs in this excess incidence of mesothelioma is unclear. Dr. Becich discussed the National Mesothelioma Virtual Bank (NMVB), a virtual mesothelioma patient registry that includes mesothelioma patients' lifetime work histories, exposure histories, biospecimens, proteogenomic information, and imaging data that can be used in epidemiology research on mesothelioma. Dr. Bernstein indicated that there is a strong consensus that long, highly durable respirable asbestiform EMPs have the potential to cause mesothelioma, but there is continued debate concerning the biodurability required, and the dimensions (both length and diameter), the shape, and the dose associated with mesothelioma risk. Finally, Dr. Nel discussed how experimental studies of High Aspect Ratio Engineered Nanomaterials have clarified dimensional and durability features that impact disease risk, the impact of inflammation and oxidative stress on the epigenetic regulation of tumor suppressor genes, and the generation of immune suppressive effects in the mesothelioma tumor microenvironment. The session ended with a discussion of future research needs.

Copyright © 2022 Gradco LLC dba Gradient. Published by Elsevier Inc. All rights reserved.
Nucleation of naturally occurring calcic amphibole asbestos. M. Misseri. 2023;230:114940. PubMed · Publisher

Abstract

This article proposes an initial model of natural asbestiform minerals growing in four stages. Structures dating from the early stages of the development were observed in the damaged zone surrounding meso-fractures, more particularly in microfractures, microcavities and microcracks that lie in front of and along mesofractures. This study is limited to calcium amphiboles cross-fibers, which develop from altered calcium amphiboles. The observations were made using PLM, with some using TEM. The samples are amphibolites, dolerites and skarns from France. All these rocks have in common that they have been exposed to hydrothermal circulation which gives them a propylite character. The earliest phenomenon was the development of metasomatic veins. In these veins, actinolite form pseudomorphs after hornblendes. The new amphiboles preserve the original morphology of hornblende, in particular the appearance of the cleavages. In the second stage, hydrothermal Fluid circulation promotes the development of subgrains (DSG) with boundaries generally parallel to the cleavage. Some sub-grains become thinner and more and more individualized due to dissolution by the hydrothermal fluid. The third stage is fracturing. The irregular ends of DSGs and amphibole debris can form the substrate of asbestiform mineral nuclei. Further dissolution of DSGs can also lead to the creation of substrates. The last stage is the nucleation and growth. The nuclei have a conical shape and variable widths, from a few microns to about ten microns. The basal parts of the asbestos minerals (BPAMs) extend the DSGs along the c axis. BPAMs have variable widths and can divide during their development at the level of transverse microcracks. BPAMs when not dividing have a morphology comparable to that of whisker nanocrystals synthesized using the vapor-liquid-crystal mechanism. The shape of the fragments from BPMAs is close to that of DSGs as both have variable widths and both have lengths controlled by microcracks.

Copyright © 2022 Elsevier Inc. All rights reserved.
Quantitative assessment of mesothelioma and lung cancer risk based on Phase Contrast Microscopy (PCM) estimates of fibre exposure: an update of 2000 asbestos cohort data. L. Darnton. 2023;230:114753. Meta-analysis PubMed · Publisher

Abstract

An earlier meta-analysis of mortality studies of asbestos-exposed worker populations, quantified excess mesothelioma and lung cancer risks in relation to cumulative exposure to the three main commercial asbestos types. The aim of this paper was to update these analyses incorporating new data based on increased follow-up of studies previously included, as well as studies of worker populations exposed predominantly to single fibre types published since the original analysis. Mesothelioma as a percentage of expected mortality due to all causes of death, percentage excess lung cancer and mean cumulative exposure were abstracted from available mortality studies of workers exposed predominantly to single asbestos types. Average excess mesothelioma and lung cancer per unit of cumulative exposure were summarised for groupings of studies by fibre type; models for pleural and peritoneal mesothelioma risk and lung cancer risk in terms of cumulative exposure for the different fibre types were fitted using Poisson regression. The average mesothelioma risks (per cent of total expected mortality) per unit cumulative exposure (f/cc.yr), RM, were 0.51 for crocidolite, 0.12 for amosite, and 0.03 for the Libby mixed amphiboles cohort. Significant heterogeneity was present for cohorts classed as chrysotile, with RM values of 0.01 for chrysotile textiles cohorts and 0.0011 for other chrysotile-exposed cohorts. Average percentage excess lung cancer risks per unit cumulative exposure, RL, were 4.3 for crocidolite and amosite combined, 0.82 for Libby. Very significant heterogeneity was present for chrysotile-exposed cohorts with RL values spanning two orders of magnitude from 0.053 for the Balangero mine to 4.8 for the South Carolina textiles cohort. Best fitting models suggest a non-linear exposure-response in which the peritoneal mesothelioma risk is proportional to approximately the square of cumulative exposure. Pleural mesothelioma and lung cancer risk were proportion to powers of cumulative exposure slightly less than one and slightly higher than one respectively.

Crown Copyright © 2023. Published by Elsevier Inc. All rights reserved.
The use of scanning electron microscopy (SEM) and energy dispersiveX-ray analysis (EDXA) as a measurement tool for EMPs tasks, guidelines. R. König. 2023;230:114790. PubMed · Publisher

Abstract

In a variety of European countries SEM/EDXA based methods are widely used for the measurements and judgements relating thereof regarding asbestos analysis. Most of these methods are used also for other fibrous particles, commonly indicated as Elongate Mineral Particles (EMPs). The span of guidelines reflects the broad use of SEM/EDXA as an analytical method. Guidelines regarding air measurements both for ambient and indoor air are well established. These methods are widely used as is shown in a proficiency testing scheme, organized by the British Health and Safety Executive (HSL) with participants from countries all over Europe and some countries from Asia and Africa. For workplaces a similar guideline with a reduced sensitivity is available, allowing measurements in higher dust concentrations. Features of the methods like analytical sensitivity, detection limits and measurement uncertainty are discussed. For material analysis we apply different analytical methods, using SEM/EDXA as a final step. They are different both in sample preparation and sensitivity. Most of the methods are qualitative or "semi-quantitative" and thought for the analysis of commercial asbestos containing products mainly. If quantitative analysis based on EDXA is used for identification other EMPs can be identified as well. An important tool is the morphological impression of the fibers or structures in the SEM in addition. Changes in regulations which may be expected, will modify some of the methods. Especially lowered Threshold Limit Values (TLV's) in occupational air measurements are difficult to achieve.

Copyright © 2022. Published by Elsevier Inc.
Ultrasensitive dose-response for asbestos cancer risk implied by new inflammation-mutation model. K.T. Bogen. 2023;230:115047. Review PubMed · Publisher

Abstract

Alterations in complex cellular phenotype each typically involve multistep activation of an ultrasensitive molecular switch (e.g., to adaptively initiate an apoptosis, inflammasome, Nrf2-ARE anti-oxidant, or heat-shock activation pathway) that triggers expression of a suite of target genes while efficiently limiting false-positive switching from a baseline state. Such switches exhibit nonlinear signal-activation relationships. In contrast, a linear no-threshold (LNT) dose-response relationship is expected for damage that accumulates in proportion to dose, as hypothesized for increased risk of cancer in relation to genotoxic dose according to the multistage somatic mutation/clonal-expansion theory of cancer, e.g., as represented in the Moolgavkar-Venzon-Knudsen (MVK) cancer model by a doubly stochastic nonhomogeneous Poisson process. Mesothelioma and lung cancer induced by exposure to carcinogenic (e.g., certain asbestos) fibers in humans and experimental animals are thought to involve modes of action driven by mutations, cytotoxicity-associated inflammation, or both, rendering ambiguous expectations concerning the nature of model-implied shape of the low-dose response for above-background increase in risk of incurring these endpoints. A recent Inflammation Somatic Mutation (ISM) theory of cancer posits instead that tissue-damage-associated inflammation that epigenetically recruits, activates and orchestrates stem cells to engage in tissue repair does not merely promote cancer, but rather is a requisite co-initiator (acting together with as few as two somatic mutations) of the most efficient pathway to any type of cancer in any reparable tissue (Dose-Response 2019; 17(2):1-12). This theory is reviewed, implications of this theory are discussed in relation to mesothelioma and lung cancer associated with chronic asbestos inhalation, one of the two types of ISM-required mutations is here hypothesized to block or impede inflammation resolution (e.g., by doing so for GPCR-mediated signal transduction by one or more endogenous autacoid specialized pro-resolving mediators or SPMs), and supporting evidence for this hypothesis is discussed.

Copyright © 2022 Elsevier Inc. All rights reserved.
Unravelling the ultramafic rock-driven serpentine soil formation leading to the geo-accumulation of heavy metals: An impact on the resident microbiome, biogeochemical cycling and acclimatized eco-physiological profiles. S. Koner, J.S. Chen, J. Rathod, et al. 2023;216(Pt 4):114664. PubMed · Publisher

Abstract

In the present study, we have underpinned the serpentine rock, serpentinized ultramafic soil and rhizosphere's microbial communities, signifying their heavy metals-exposed taxa signatures and functional repertoires in comparison to non-serpentine soils. The results revealed that the serpentine rock embedded soil highlighted the geo-accumulation of higher amount of Cr and Ni impacting soil microbial diversity negatively by metal stress-driven selection. Biolog Ecoplate CLPP defined a restricted spectrum of C-utilization in the higher heavy metal-containing serpentine samples compared to non-serpentine. The linear discriminant analysis (LDA) score identified a higher abundance of Desulfobacterota, Opitutales, and Bacteroidales in low Cr and Ni-stressed non-serpentine-exposed samples. Whereas the abundance of Propionibacteriales and Actinobacteriota were significantly enriched in the serpentine niche. Further, the C, N, S, Fe, and methane biogeochemical cycles linked functional members were identified, and showing higher functional diversity in low Cr and Ni concentration-containing rhizosphere JS-soils. The Pearson correlation coefficient (r) value confirmed the abundance of functional members linked to specific biogeochemical cycle, positively correlated with relevant pathway enrichment. Ultimately, this study highlighted the heavy metal stress within a serpentine setting that could limit the resident microbial community's metabolic diversity and further select the bacteria that could thrive in the serpentine-associated heavy metal-stressed soils. These acclimatized microbes could pave the way for the future applications in the soil conservation and management.

Copyright © 2022 Elsevier Inc. All rights reserved.
Distance impacts toxic metals pollution in mining affected river sediments. C.Y. Lin, B.N. Mohammad Ali, R. Tair, et al. 2022;214(Pt 1):113757. PubMed · Publisher

Abstract

The study of metals mobility derived from mining activities in an ultramafic lithology is limited. This study investigates the effects of distance on potentially toxic metals such as Co, Cu, Fe, Mn, Ni, Pb, and Zn pollution, and the geochemical processes of fluvial system downstream of an ex-copper mine (Mamut River). The toxicity level of the river was evaluated using various sediment quality guidelines, ecotoxicological risks (ecological risk and risk index) and pollution indices. The geochemical behavior and stability of these toxic metals in the solid-phase samples were also examined. The results show that elevated concentrations of Ni, Cu, and Fe in the sediments can be linked to the adsorption and precipitation of metals from the aqueous-phase samples. We found that the metal scavenging rate as a function of distance is more evident in tropical environments than it was previously thought (10 km downstream). Such an inference could be explained by the greater amount of rainfall (pH 5.5-6.5) received in the tropics and higher weathering products that could react and form stable complexes. Geochemical analysis of the river sediment indicates that Ni, Cu, and Fe in the river sediment have increased 44-, 81-, and 90-fold compared to the background values, respectively. A significant decrease in the concentration of the potentially toxic metals was found at 5.5 km downstream. The scavenging rate of Fe is the highest (1485.82 μg g-1 km-1) followed by Cu (141.48 μg g-1 km-1), Ni (10.23 μg g-1 km-1), Pb (8.12 μg g-1 km-1) and Zn (5.01 μg g-1 km-1) in the tropical river system. In contrast, the concentration of Co and Mn in the river sediments doubled as the river flows approximately 5 km downstream due to the higher mineral solubility and weaker metal partition coefficient. This study also discusses the possibility of asbestos (mainly as chrysotile in the X-ray diffraction) as a potential hidden risk present within the ultramafic setting. This case study can be extrapolated to explain the dispersion of inorganic pollutants in an ultramafic environment in a global context.

Copyright © 2022 Elsevier Inc. All rights reserved.
Mortality in the cohort of talc miners and millers from Val Chisone, Northern Italy: 74 years of follow-up. C. Ciocan, E. Pira, M. Coggiola, et al. 2022;203:111865. PubMed · Publisher

Abstract

Objective: To update the analysis of mortality of a cohort of talc miners and millers in Northern Italy.

Methods: We analyzed overall mortality and mortality from specific causes of death during 1946-2020 of 1749 male workers in a talc mine where asbestos was not detected (1184 miners and 565 millers) employed during 1946-1995.

Results: The overall standardized mortality ratio (SMR) was 1.21 (95 % confidence interval [CI] 1.14-1.28); no deaths were observed from pleural cancer. Mortality from lung cancer was not increased (SMR = 1.02 95 % CI 0.82-1.27), while mortality from pneumoconiosis was (SMR 9.55; 95 % CI 7.43-12.08), especially among miners (SMR 12.74; 95 % CI 9.79-16.31). There was a trend in risk of pneumoconiosis with increasing duration of employment in the overall cohort, and the SMR for 25+ years of employment was 15.12 (95 % CI 10.89-20.43).

Conclusions: This uniquely long-term follow up confirms the results of previous analyses, namely the lack of association between exposure to talc with no detectable level of asbestos and lung cancer and mesothelioma. Increased mortality from pneumoconiosis among miners is related to past exposure to silica.

Copyright © 2021. Published by Elsevier Inc.
Asbestos contamination on brownfield development sites in the UK. E.E. Hellawell, S.J. Hughes. 2021;198:110480. PubMed · Publisher

Abstract

The development of brownfield sites in the UK requires site investigation for contamination as part of the regulatory planning process. This site investigation includes the collection of soil samples that are analysed for asbestos contamination. This research project analyses this untapped resource of brownfield asbestos data, using site investigation data submitted to a local Borough Council, in Surrey, UK. Over 100 site investigation reports were collected. This paper presents the trends in asbestos testing from 2001 to 2019 and data on the location, concentration, form and type of asbestos found in this Borough. The rate of asbestos detection has increased significantly, reflecting improvements in asbestos measuring techniques, to a rate of 22% for all samples tested between 2016 and 2019. The concentrations of asbestos found were very low, with 74% of samples having concentrations below the limit of detection of the laboratory and were predominantly of fibrous form. A significant proportion of samples contained more carcinogenic amphibole type. Most of the asbestos was found in the top 1 m of Made Ground soil. Site history was found to be important with gas works having the highest asbestos detection rate, though a detection rate of 10% was found in soil samples on former residential sites. This information is important to inform and update risk assessment for site workers and site remediation in relation to asbestos. Hence based upon these results, a qualitative risk chart for asbestos is presented to provide guidance and in-sight into asbestos on brownfield sites for local authorities and developers.

Copyright © 2020 Elsevier Inc. All rights reserved.
Exploration of identifying novel serum biomarkers for malignant mesothelioma using iTRAQ combined with 2D-LC-MS/MS. H. Xia, L. Feng, L. Lin, et al. 2021;193:110467. PubMed · Publisher

Abstract

Malignant mesothelioma (MM) is an aggressive cancer linked to asbestos exposure. Its poor prognosis makes early diagnosis extremely important, which would provide an opportunity for early treatment and potentially changing outcomes. This study aimed to explore the underlying mechanisms of MM and discover novel noninvasive biomarkers for the diagnosis of malignant mesothelioma. Using Isobaric tags for relative and absolute quantitation (iTRAQ) combined with two-dimensional liquid chromatography/tandem mass spectrometry (2D LC-MS/MS), a total of 145 differentially expressed serum proteins were identified between MM patients and healthy controls. The identified proteins were further analyzed by bioinformatics, out of which three candidate biomarkers (Filamin A (FLNA), Fibulin 1 (FBLN1) and Thrombospondin-1 (TSP-1)) were validated in large cohorts of patients with asbestos-related diseases including MM patients by ELISA assay. Receiver operating characteristic (ROC) curve analysis showed that serum FLNA, FBLN1 and TSP-1 had high diagnostic values in distinguishing MM patients from healthy controls, individuals with asbestos exposure (AE), and patients with pleural plaques (PP) or asbestosis. Meanwhile, serum FBLN1 and TSP-1 possessed good diagnostic values in distinguishing asbestosis patients from healthy controls and individuals with AE. The combination of FLNA, FBLN1, and TSP-1 proteins had higher sensitivity and specificity in discriminating patients with MM, PP and asbestosis. Our findings indicated that analysis of serum proteome using iTRAQ is a feasible strategy for biomarker discovery, and serum FLNA, FBLN1 and TSP-1 may be promising candidates for diagnosis of malignant mesothelioma and screening of at-risk individuals.

Copyright © 2020 Elsevier Inc. All rights reserved.
Estimate of environmental and occupational components in the spatial distribution of malignant mesothelioma incidence in Lombardy (Italy). D. Catelan, D. Consonni, A. Biggeri, et al. 2020;188:109691. PubMed · Publisher

Abstract

Introduction: Measuring and mapping the occurrence of malignant mesothelioma (MM) is a useful means to monitor the impact of past asbestos exposure and possibly identify previously unknown sources of asbestos exposure.

Objective: Our goal is to decompose the observed spatial pattern of incidence of MM in the Lombardy region (Italy) in gender-specific components linked to occupational exposure and a shared component linked to environmental exposure.

Materials And Methods: We selected from the Lombardy Region Mesothelioma Registry (RML) all incident cases of MM (pleura, peritoneum, pericardium, and tunica vaginalis testis) with first diagnosis in the period 2000-2016. We mapped at municipality level crude incidence rates and smoothed rates using the Besag York and Mollié model separately for men and women. We then decomposed the spatial pattern of MM in gender-specific occupational components and a shared environmental component using a multivariate hierarchical Bayesian model.

Results: We globally analyzed 6226 MM cases, 4048 (2897 classified as occupational asbestos exposure at interview) in men and 2178 (780 classified as occupational asbestos exposure at interview) in women. The geographical analysis showed a strong spatial pattern in the distribution of incidence rates in both genders. The multivariate hierarchical Bayesian model decomposed the spatial pattern in occupational and environmental components and consistently identified some known occupational and environmental hot spots. Other areas at high risk for MM occurrence were highlighted, contributing to better characterize environmental exposures from industrial sources and suggesting a role of natural sources in the Alpine region.

Conclusion: The spatial pattern highlights areas at higher risk which are characterized by the presence of industrial sources - asbestos-cement, metallurgic, engineering, textile industries - and of natural sources in the Alpine region. The multivariate hierarchical Bayesian model was able to disentangle the geographical distribution of MM cases in two components interpreted as occupational and environmental.

Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.
Impact of an asbestos cement factory on mesothelioma incidence in a community in Italy. D. Consonni, S. De Matteis, B. Dallari, et al. 2020;183:108968. PubMed · Publisher

Abstract

Background: Broni is a small town (9000 inhabitants) in the province of Pavia, Lombardy, north-west Italy, where the second largest Italian asbestos cement factory (Fibronit) was in operation between 1932 and 1993. Based on Lombardy Mesothelioma Registry (RML) data (2000-2011), we previously showed a high impact of asbestos exposure on malignant mesothelioma (MM) incidence among Fibronit workers, their families, and people living in Broni and in the nearby town of Stradella (11,000 residents). Given the great concern of the community, we have recently updated the data regarding 5 more years (2012-2016).

Methods: From the RML database we extracted subjects who ever worked in Fibronit, their family members, ever residents in Broni, and subjects living in Stradella and nearby towns at the time of diagnosis. For each type of exposure we calculated standardized incidence ratios (SIR = observed/expected cases).

Results: In the period 2000-2016 we registered 56 cases (2.52 expected, SIR = 22.2), 49 men (41 pleural, 8 peritoneal MM), 7 women (5 pleural, 2 peritoneal MM) with past occupational exposure in Fibronit. Among subjects never occupationally exposed and never exposed to extra-occupational sources unrelated to Fibronit, we counted 39 cases (4.24 expected, SIR = 9.2), 10 men (all pleural MM), 29 women (28 pleural, 1 peritoneal MM) in Fibronit workers' families, 91 pleural mesothelioma cases (7.43 expected, SIR = 12.2, 31 men, 60 women), ever residents in Broni, and 25 pleural mesothelioma cases (3.05 expected, SIR = 8.2, 6 men, 19 women) living in Stradella at the time of diagnosis. The overall number of excess cases was about 194 (211 against 17.24 expected). In the remaining adjacent (No. 8) and surrounding (No. 17) municipalities (32,000 people) there were 7 cases (1 men, 6 women, 8.85 expected).

Conclusion: The mesothelioma burden related to the asbestos cement factory is still high on factory workers, their families, and residents in Broni and Stradella towns.

Copyright © 2019 The Author(s). Published by Elsevier Inc. All rights reserved.
Nonlinear dose-time-response functions and health-protective exposure limits for inflammation-mediated diseases. L.A. Cox. 2020;182:109026. PubMed · Publisher

Abstract

Why have occupational safety regulations in the United States not been more successful in protecting worker health from mesothelioma risks, while apparently succeeding relatively well in reducing silicosis risks? This paper briefly discusses biological bases for thresholds and nonlinearities in exposure-response functions for respirable crystalline silica (RCS) and asbestos, based on modeling a chronic inflammation mode of action (mediated by activation of the NLRP3 inflammasome, for both RCS and asbestos). It applies previously published physiologically based pharmacokinetic (PBPK) models to perform computational experiments illuminating how different time courses of exposure with the same time-weighted average (TWA) concentration affect internal doses in target tissues (lung for RCS and mesothelium for asbestos). Key conclusions are that (i) For RCS, but not asbestos, limiting average (TWA) exposure concentrations also tightly constrains internal doses and ability to trigger chronic inflammation and resulting increases in disease risks (ii) For asbestos, excursions (i.e., spikes in concentrations); and especially the times between them are crucial drivers of internal doses and time until chronic inflammation; and hence (iii) These dynamic aspects of exposure, which are not addressed by current occupational safety regulations, should be constrained to better protect worker health. Adjusting permissible average exposure concentration limits (PELs) and daily excursion limits (ELs) is predicted to have little impact on reducing mesothelioma risks, but increasing the number of days between successive excursions is predicted to be relatively effective in reducing worker risks, even if it has little or no impact on TWA average concentrations.

Copyright © 2019 Elsevier Inc. All rights reserved.
Occupational exposure to unintentionally emitted nanoscale particles and risk of cancer: From lung to central nervous system - Results from three French case-control studies. G. Manangama, C. Gramond, S. Audignon-Durand, et al. 2020;191:110024. PubMed · Publisher

Abstract

Objectives: Nanoscale particles (1-100 nm) can be of natural origin, and either intentionally or unintentionally produced by human activities. Toxicological data have suggested a possible carcinogenic effect of such particles. The aim of this study was to estimate the association between occupational exposure to nanoscale particles and risk of lung cancer, pleural mesothelioma and brain tumors in adults.

Methods: Three French population-based case-control studies were analyzed: 1) the ICARE study including 2029 lung cancer cases and 2591 controls; 2) the PNSM study including 371 pleural mesothelioma cases and 730 controls and 3) the CERENAT study including 257 brain tumor cases and 511 controls. Occupational exposure to unintentionally emitted nanoscale particles (UNPs) was retrospectively assessed by a job exposure matrix providing a probability and a frequency of exposure.

Results: In adjusted analyses among men, significant associations between occupational exposure to UNPs and lung cancer (OR = 1.51; 95% CI: 1.22-1.86 and brain tumors (OR = 1.69; 95% CI: 1.17-2.44) were observed. No increased OR was observed for pleural mesothelioma (OR = 0.78; 95% CI: 0.46-1.33).

Conclusion: This is the first study showing positive associations between occupational exposure to UNPs and increased risk of lung cancer and brain tumors. These preliminary results should encourage further epidemiological research.

Copyright © 2020 Elsevier Inc. All rights reserved.
The challenges of applying an Activity-Based Sampling methodology to estimate the cancer risk associated with asbestos contaminated landfilled zones. M.F. Cely-García, B. Lysaniuk, R. Pasetto, et al. 2020;181:108893. PubMed · Publisher

Abstract

Inhabitants of Sibaté (Colombia) report that between approximately 1975 and 1985 asbestos-containing materials (ACM) were dumped at different locations in the urban area of the municipality. Starting in around 1986, the dumping of materials resulted in landfilled zones, on top of which different facilities were then constructed. In a previous study, an underground friable asbestos layer was discovered in these landfilled zones. However, potential exposure to asbestos on the surface of landfilled zones in Sibaté has not been determined. In the current study, the U.S. EPA Activity-Based Sampling (ABS) methodology was adapted and applied in three scenarios located on potential landfilled areas in Sibaté, to estimate the current risk of exposure to asbestos through inhalation, and the resulting excess lifetime cancer risk (ELCR). For this purpose, generic ABS in a football stadium, and specific ABS in both a public playground and a school courtyard were conducted. Personal, area and blank samples were collected and analyzed using phase contrast microscopy (PCM) and transmission electron microscopy (TEM) following NIOSH 7400 and ISO 13794 methods, respectively. Exposure point concentrations were determined and compared against the action level for asbestos in air (ALAA), and were also used to calculate the ELCR of each scenario. A total of 25 airborne asbestos samples were collected, and 22 of these (12 personal samples, 7 area samples and 3 blank samples) were analyzed using PCM. Eighteen of these samples (12 personal, 3 area samples and 3 blank samples) were analyzed using TEM. The total asbestos structures concentration of personal samples ranged from non-detected to 0.326 S/cc (i.e., total asbestos structures counts ranged from 0 to 12). All samples had PCM-Equivalent asbestos structures concentrations below analytical sensitivity. Of the 22 samples analyzed, 18 were overloaded with particles. Although chrysotile and actinolite were identified in some personal samples, suggesting a potential risk of asbestos exposure, the ELCR was at U.S. EPA acceptable risk levels. Since the ABS methodology was applied in a limited number of scenarios and a small number of samples were collected, these results should be interpreted with caution and additional sampling campaigns are required to fully understand the risk of asbestos exposure in Sibaté. Methodological and analytical challenges encountered in the current study are discussed in detail, which could inform future ABS studies, not only in Sibaté, but also in other areas with asbestos-contaminated soils.

Copyright © 2019 Elsevier Inc. All rights reserved.
Where are the landfilled zones? Use of historical geographic information and local spatial knowledge to determine the location of underground asbestos contamination in Sibaté (Colombia). B. Lysaniuk, M.F. Cely-García, A. Mazzeo, et al. 2020;191:110182. PubMed · Publisher

Abstract

Introduction: Sibaté is a municipality located in the central region of Colombia, where the first asbestos-cement facility of the country has been in operation since 1942. Both a malignant pleural mesothelioma cluster and landfilled zones with the presence of an underground friable asbestos layer have been identified in Sibaté. There is still limited knowledge regarding the history of the construction of landfilled zones, and what kinds of materials were deposited. The current study aims to improve our understanding of the history and characteristics of the landfilled zones present in Sibaté.

Methods: Two participatory workshops with inhabitants of Sibaté were conducted to determine when the landfilled zones were built and their location. Information collected in participatory workshops was crossed with both topographic maps and aerial photographs, giving special attention to zones within the urban area of the municipality that in the past were inundated with water from El Muña Reservoir. An opportunistic soil sampling campaign was conducted in suspected landfilled zones that had not been previously sampled, during the replacement of pipelines of the drainage system ordered by the municipality.

Results: The analysis of historical topographic maps, combined with the interpretation of aerial photographs, confirmed the disposal of residues in areas that were previously inundated with water from El Muña Reservoir, creating landfilled zones in the urban area of Sibaté. On top of these landfilled zones, a football stadium and a football field with an athletic track were built. The location of landfilled zones identified using geographic analysis was similar to the location identified analyzing maps constructed by inhabitants of Sibaté in participatory workshops. The four soil samples collected during an opportunistic sampling campaign confirmed the presence in new locations of the underground friable asbestos layer discovered in previous studies.

Discussion: Based on the extension of the landfilled zones, the presence of friable asbestos in these areas, and the close proximity to a school and residential dwellings, there could have been major dispersion events of asbestos fibers in the urban area of Sibaté during the disposal of residue materials and the construction of the landfilled zones. Thus, important asbestos exposures may have occurred among residents of Sibaté, which is aggravated by the fact that during those years, more than 50% of the population of Sibaté was 25 years old or younger. Although the results of the current study improved our understanding of the processes and chronology associated with the landfilled zones, the uncertainty regarding their exact location remains significant. It is important to continue investigating the adverse health effects resulting from this potential asbestos exposure source.

Copyright © 2020 Elsevier Inc. All rights reserved.

2010s

An asbestos contaminated town in the vicinity of an asbestos-cement facility: The case study of Sibaté, Colombia. J.P. Ramos-Bonilla, M.F. Cely-García, M. Giraldo, et al. 2019;176:108464. PubMed · Publisher

Abstract

Introduction: The asbestos industry began operations in Colombia in 1942, with an asbestos-cement facility located in the municipality of Sibaté. In recent years residents from Sibaté have been complaining about what they consider is an unusually large number of people diagnosed with asbestos-related diseases in the town. A study to analyze the situation of Sibaté started in 2015, to verify if the number of asbestos related diseases being diagnosed were higher than expected, and to identify potential asbestos exposure sources in the town.

Methods: A health and socioeconomic survey was implemented door-to-door to identify potential asbestos-related diseases. Several self-reported mesothelioma cases were identified, and for confirmation purposes, copies of the medical record with the histopathology report were obtained. A panel of six physicians analyzed the medical records. Information of validated cases was used to estimate the male and female age-adjusted incidence rate for Sibaté. Based on reports of the existence of potential asbestos-contaminated landfills, topographic maps, a digital elevation model, and current satellite images were crossed using a geographic information system to identify potential landfilled areas, and soils samples were collected in some of these areas.

Results: A total of 355 surveys were completed, and 29 self-reported mesothelioma cases were identified. Twenty-five of these cases have been persons who had lived at some moment of their lives in Sibaté. It was possible to obtain copies of the medical diagnosis for 17 cases. Of these, the panel of physicians classified 15 cases as certain pleural mesothelioma, one as probable, and one as not mesothelioma. Based on this information, the estimated age-adjusted incidence rate of mesothelioma in Sibaté was 3.1 × 105 persons-year for males and 1.6 × 105 persons-year for females. These rates are high in comparison to those reported in other cities, regions, and countries of the world. Using geographic information systems, landfilled zones in the urban area of Sibaté were identified, on top of which a school and different sports facilities were built. The analysis of four soil samples collected in landfilled zones, confirmed the existence of an underground layer of friable and non-friable asbestos.

Conclusion: The collected evidence suggests the presence of a malignant pleural mesothelioma cluster in Sibaté.

Copyright © 2019. Published by Elsevier Inc.
Biodurability and release of metals during the dissolution of chrysotile, crocidolite and fibrous erionite. A.F. Gualtieri, G. Lusvardi, A. Zoboli, et al. 2019;171:550-557. PubMed · Publisher

Abstract

Background: The mechanisms by which mineral fibers induce adverse effects in vivo are still not well understood. The mechanisms of fiber dissolution in the lungs and subsequent release of metals in the extracellular/intracellular environment must be taken into account.

Aim: For the first time, the kinetics of release of metals during the acellular in vitro dissolution of chrysotile, crocidolite and fibrous erionite were determined.

Methods: In vitro acellular dissolution of chrysotile, crocidolite, and fibrous erionite-Na was conducted using a solution mimicking the phagolysosome environment active during the phagocytosis process (pH=4.5, at 37 °C). The kinetics of release of a representative selection of metals were determined over a period of three months.

Results: Despite the fact that the difference in Fe content between chrysotile and crocidolite is one order of magnitude, the much faster dissolution rate of chrysotile compared to crocidolite prompts greater release of available active surface Fe in the first weeks of the dissolution experiment and comparable amounts after 90 d. Such active iron may promote the formation of toxic hydroxyl radicals. The fast release of metals like Cr, Ni and Mn from chrysotile is also a source of concern whereas the release of V in solution is negligible.

Conclusion: Because chrysotile undergoes fast dissolution with respect to crocidolite and fibrous erionite, it behaves like a carrier that releases its metals' cargo in the lung environment, mimicking the phenomenon that explains the toxicity of nanoparticles. Hence, the toxicity paradigm of a non biodurable fiber like chrysotile should also take into account the release of toxic metals in the intracellular/extracellular medium during the rapid dissolution process.

Copyright © 2019 Elsevier Inc. All rights reserved.
Cancer incidence and mortality associated with non-occupational and low dose exposure to Libby vermiculite in Minnesota. T. Konen, J.E. Johnson, P. Lindgren, et al. 2019;175:449-456. PubMed · Publisher

Abstract

Background: A vermiculite processing plant in a Minneapolis, Minnesota neighborhood utilized asbestos-containing ore from Libby, Montana from the late 1930's until 1989. Multiple pathways of exposure to Libby asbestos were characterized in a cohort of over 6000 plant workers and residents living near the plant.

Objective: We conducted a cohort linkage study to assess the impact of cumulative low dose exposure and the role of occupational history on asbestos-related mortality and cancer morbidity among cohort members residing near a vermiculite plant.

Methods: Cohort members alive in 1988 (n = 5848) were linked to the Minnesota Cancer Surveillance System to identify incident cases of mesothelioma, lung cancer, and all-cancer diagnosed from 1988 to 2010. Proportional incidence ratios (PIRs) were calculated for mesothelioma and lung cancer. Vital status and cause of death were ascertained from Minnesota vital records and the National Death Index (1988-2011). Mortality rates of the cohort (2001-2011) for asbestos-related outcomes were compared to the Minnesota population to estimate standardized mortality ratios (SMRs) and stratified by gender, exposure, and occupational history categories.

Results: We identified seven cases of mesothelioma, with elevated incidence only in females (PIR = 11.76, 95% CI: 3.17, 30.12). Lung cancer was elevated in both genders: PIR = 1.54 (95% CI: 1.19, 2.0) in males and 1.62 (95% CI: 1.21, 2.12) in females. We found elevated mortality from COPD, lung cancer, and mesothelioma among females (SMR for mesothelioma in females = 18.97, CI: 3.91, 55.45), among the 546 deaths identified. All four deaths from mesothelioma occurred in the >75th percentile of exposure (>0.0156 fiber/cc x months). The SMR for lung cancer and all respiratory cancer was elevated even after controlling for occupation.

Conclusions: Community exposure to Libby amphibole asbestos from a vermiculite processing plant is associated with increased risk of COPD, lung cancer and mesothelioma incidence and mortality, most notably among females, and is likely to remain a public health issue for years to come.

Published by Elsevier Inc.
Characterization and assessment of the potential toxicity/pathogenicity of fibrous glaucophane. D. Di Giuseppe, M. Harper, M. Bailey, et al. 2019;178:108723. PubMed · Publisher

Abstract

In California, the metamorphic blueschist occurrences within the Franciscan Complex are commonly composed of glaucophane, which can be found with a fibrous habit. Fibrous glaucophane's potential toxicity/pathogenicity has never been determined and it has not been considered by the International Agency for Research on Cancer (IARC) as a potential carcinogen to date. Notwithstanding, outcrops hosting fibrous glaucophane are being excavated today in California for building/construction purposes (see for example the Calaveras Dam Replacement Project - CDRP). Dust generated by these excavation activities may expose workforces and the general population to this potential natural hazard. In this work, the potential toxicity/pathogenicity of fibrous glaucophane has been determined using the fibre potential toxicity index (FPTI). This model has been applied to a representative glaucophane-rich sample collected at San Anselmo, Marin County (CA, USA), characterized using a suite of experimental techniques to determine morphometric, crystal-chemical parameters, surface reactivity, biodurability and related parameters. With respect to the asbestos minerals, the FPTI of fibrous glaucophane is remarkably higher than that of chrysotile, and comparable to that of tremolite, thus supporting the application of the precautionary approach when excavating fibrous glaucophane-rich blueschist rocks. Because fibrous glaucophane can be considered a potential health hazard, just like amphibole asbestos, it should be taken into consideration in the standard procedures for the identification and assessment of minerals fibres in soil and air samples.

Copyright © 2019 Elsevier Inc. All rights reserved.
Gender differences in pleural mesothelioma occurrence in Lombardy and Piedmont, Italy. D. Consonni, E. Migliore, F. Barone-Adesi, et al. 2019;177:108636. PubMed · Publisher

Abstract

Background: Higher mesothelioma rates in men (vs women) reflect more frequent and more intense asbestos exposure. We assessed the impact of exposure difference between genders on age-specific rates of pleural mesothelioma (PM) occurrence using data from two Italian regions.

Methods: We used data from the Lombardy and Piedmont mesothelioma registries (period 2000-2016, age 45-74 years) to compare rates of PM in men and women and to estimate the rate advancement period (RAP).

Results: Based on 3384 cases (2405 men, 979 women) in Lombardy and 2042 (1389 men, 653 women) in Piedmont, the rate ratio was 2.81 (90% confidence interval: 2.61-3.03) in Lombardy and 2.39 (2.17-2.62) in Piedmont. In both regions RAP ranged from 7 to 10 years (at age 45 and 63 in men, respectively).

Conclusion: Men showed more than twofold increased PM rates and reached the same incidence as women 7-10 years earlier. RAP can be a useful measure of exposure impact on premature disease occurrence.

Copyright © 2019 Elsevier Inc. All rights reserved.
Heavy metals, welding fumes, and other occupational exposures, and the risk of kidney cancer: A population-based nested case-control study in three Nordic countries. I.M. Michalek, J.I. Martinsen, E. Weiderpass, et al. 2019;173:117-123. PubMed · Publisher

Abstract

Objectives: To determine whether occupational exposure to heavy metals (chromium (VI), iron, nickel, lead) and welding fumes is associated with the risk of kidney cancer and to describe whether other occupational exposures included in the Job Exposure Matrix of the Nordic Occupational Cancer (NOCCA) study are associated with the risk.

Materials And Methods: Nested case-control study among individuals registered in population censuses in Finland, Iceland, and Sweden in 1960-1990. A total of 59,778 kidney cancer cases, and 298,890 controls matched on sex, age, and country. Cumulative occupational exposures to metals (chromium (VI), iron, nickel, lead), welding fumes, and 24 other occupational exposure covariates, lagged 0, 10, and 20 years.

Results: Overall, there was no or very little association between kidney cancer and exposures studied. The risk was elevated in individuals with high exposure to asbestos (OR 1.19, 95%CI 1.08-1.31). The risk was significantly decreased for individuals characterized with high perceived physical workload (OR 0.86, 95%CI 0.82-0.91), high exposure to ultraviolet radiation (OR 0.85, 95%CI 0.79-0.92), and high exposure to wood dust (OR 0.82, 95%CI 0.71-0.94). The risk of kidney cancer under the age of 59 was elevated in individuals with high exposure to nickel (OR 1.49, 95%CI 1.03-2.17). The risk of kidney cancer in age 59-74 years was elevated for individuals with high exposure to iron (OR 1.41, 95%CI 1.07-1.85), and high exposure to welding fumes (OR 1.43, 95%CI 1.09-1.89).

Conclusions: The only markedly elevated risks of kidney cancer were seen for the highest exposures of nickel and iron/welding fumes in specific age strata.

Copyright © 2019 Elsevier Inc. All rights reserved.
Malignant mesothelioma in Sub-Saharan Africa: A case report from Lubumbashi, DR Congo. J. Pyana Kitenge, D. Kapinga Kayembe, M. Tshibangu Muamba, et al. 2019;176:108556. Case report PubMed · Publisher

Abstract

Although asbestos has been used throughout Africa in the past decades, no reports of asbestos-related malignant mesothelioma are available from sub-Saharan Africa, except from South Africa and Zimbabwe. We present a case of a 39-year-old man who died from a histologically proven malignant mesothelioma of the peritoneum in Lubumbashi, DR Congo. No occupational exposure to asbestos could be found in his history. In view of his young age, we speculated that he had been exposed to asbestos as a child, which was highly plausible because he had grown up in one of the numerous mining estates of the region. The houses of these estates were often built with asbestos-containing materials, notably roofs made of corrugated asbestos-cement. The possibility of past domestic or environmental exposure to asbestos was substantiated by the identification of chrysotile and crocidolite fibres in samples of asbestos-cement collected from the home where the patient had lived as a child. To our knowledge, this is the first report of malignant mesothelioma from a country in the Central African region. We expect that heightened awareness and improved diagnosis will lead to the detection of more asbestos-related diseases in Africa.

Copyright © 2019 Elsevier Inc. All rights reserved.
National and subnational mortality and disability-adjusted life years (DALYs) attributable to 17 occupational risk factors in Iran, 1990-2015. M. Abtahi, A. Koolivand, S. Dobaradaran, et al. 2018;165:158-175. PubMed · Publisher

Abstract

We estimated age-sex specific and cause-specific mortality, years of life lost due to premature mortality (YLLs), years lived with disability (YLDs) and disability-adjusted life years (DALYs) attributable to 17 individual occupational risks in Iran at the national and subnational levels in 1990-2015 based on the Global Burden of Disease Study 2015 (GBD 2015). The burden of disease attributable to occupational risk factors was calculated using the comparative risk assessment methodology based on 10 outcomes and 21 risk-outcome pairs. The temporal changes in the attributable burden of disease were decomposed into the contribution of population growth, population ageing, risk-deleted DALY rate, and risk exposure. National DALYs attributable to occupational risks at the national level in 1990, 2005, and 2015 were 138,210 (95% uncertainty interval 64,429-223,028), 193,243 (91,645-310,281), and 228,310 (106,782-371,709), respectively indicating a total increase of 65% (65-67) during the study period. Between 1990 and 2015, the share of the attributable DALYs for women rose by 55% (51-58) from 13% (12-14) to 20% (19-21). The proportion of YLLs in national DALYs attributable to occupational risks during the study period slightly decreased from 24% in 1990 to 23% in 2015. The five occupational risks with the highest contributions in the national attributable DALYs in 2015 were ergonomic factors (107,490), noise (52,122), exposure to particulate matter, gases, and fumes (26,847), asthmagens (19,347), and exposure to asbestos (7842). From 1990 to 2015, the increase in total DALYs attributable to occupational carcinogens (112%) was higher than that for other occupational risks. During the study period, changes in risk deleted DALY rate and risk exposure led to decreases in total DALYs attributable to occupational risks by 14% and 30%, respectively. Based on the Gini coefficient, spatial inequality in DALY rate attributable to occupational risks at the provincial level decreased during 1990-2015. A comprehensive plan for management of exposure to occupational risks, especially occupational carcinogens can cause an important effect for control of the increasing trend of occupational health losses.

Copyright © 2018 Elsevier Inc. All rights reserved.
Analysis of fibulin-3 after exposure to asbestos-like fibers. V. Rapisarda, R. Caltabiano, G. Musumeci, et al. 2017;156:381-387. PubMed · Publisher

Abstract

A significantly increased incidence of malignant mesothelioma in Biancavilla (Sicily, Italy) has been ascribed to exposure to fluoro-edenite, a fibrous amphibole extracted from a local stone quarry. Fibulin-3 is a highly conserved glycoprotein proposed as a biomarker for malignant mesothelioma that belongs to the family of extracellular matrix proteins. Previous studies demonstrated high Fibulin-3 plasma levels in workers with pleural plaques exposed to fluoro-edenite. Therefore, in order to gain insight into the biomolecular mechanisms of fluoro-edenite toxicity, we performed the analysis of Fibulin-3 expression by immunohistochemistry in the lung samples derived from sheep belonging to the area of Biancavilla. Furthermore, an in vitro model of exposed fluoro-edenite fibroblasts was used to perform functional experiments to better understand the modulation of Fibulin-3 expression. The percentage of immunostained area by Fibulin-3 was very much higher in exposed lungs compared with non-exposed ones. The Fibulin-3 protein level was significantly expressed in primary human lung fibroblasts exposed to 50 and 100µg/ml of fluoro-edenite fibers for 72h, compared to the unexposed controls. The results from the present study further demonstrate the implication of Fibulin-3 during fluoro-edenite exposure. This would endorse our previous results regarding the use of Fibulin-3 as a possible screening biomarker for fluoro-edenite exposed individuals, thereby contributing to the monitoring of the population at risk. The present study also suggested that the Fibulin-3 overexpression may reflect a defensive response of the tissues after exogenous stimuli and may be implicated in cancer development, especially in the context of fluoro-edenite contamination. However, further studies are necessary in order to make Fibulin-3 a customized screening tool.

Copyright © 2017 Elsevier Inc. All rights reserved.
Childhood exposure to Libby amphibole asbestos and respiratory health in young adults. P.H. Ryan, C.H. Rice, J.E. Lockey, et al. 2017;158:470-479. PubMed · Publisher

Abstract

Objectives: Vermiculite ore containing Libby amphibole asbestos (LAA) was mined in Libby, MT, from the 1920s-1990. Recreational and residential areas in Libby were contaminated with LAA. This objective of this study was to characterize childhood exposure to LAA and investigate its association with respiratory health during young adulthood.

Methods: Young adults who resided in Libby prior to age 18 completed a health and activity questionnaire, pulmonary function testing, chest x-ray and HRCT scan. LAA exposure was estimated based on participant report of engaging in activities with potential LAA exposure. Quantitative LAA estimates for activities were derived from sampling data and literature reports.

Results: A total of 312 participants (mean age 25.1 years) were enrolled and reported respiratory symptoms in the past 12 months including pleuritic chest pain (23%), regular cough (17%), shortness of breath (18%), and wheezing or whistling in the chest (18%). Cumulative LAA exposure was significantly associated with shortness of breath (aOR = 1.12, 95% CI 1.01-1.25 per doubling of exposure). Engaging in recreational activities near Rainy Creek Road (near the former mine site) and the number of instances heating vermiculite ore to make it expand or pop were also significantly associated with respiratory symptoms. LAA exposure was not associated with pulmonary function or pleural or interstitial changes on either chest x-ray or HRCT.

Conclusions: Pleural or interstitial changes on x-ray or HRCT were not observed among this cohort of young adults. However, childhood exposure to LAA was significantly associated with respiratory symptoms during young adulthood. Pleuritic chest pain, in particular, has been identified as an early symptom associated with LAA exposure and therefore warrants continued follow-up given findings of progressive disease in other LAA exposed populations.

Copyright © 2017 Elsevier Inc. All rights reserved.
A task-based assessment of parental occupational exposure to organic solvents and other compounds and the risk of childhood leukemia in California. C. Metayer, G. Scelo, A.Y. Kang, et al. 2016;151:174-183. PubMed · Publisher · Free full text

Abstract

Purpose: Data on parental occupational exposures and risk of childhood leukemia lack specificity. Using 19 task-based job modules, we examined the relationship between occupational exposure to organic solvents and other compounds and the risk of leukemia in children.

Methods: Latino (48%) and non-Latino (52%) children with acute lymphoblastic leukemia (ALL; n=670), acute myeloid leukemia (AML; n=104), and controls (n=1021) were enrolled in a study in California (2000-2008). Logistic regression models were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs), adjusted for socio-demographic factors.

Results: Among children with non-Latino fathers, none of the exposures evaluated were associated with risks of ALL and AML. In contrast, exposure to any organic solvents in Latino fathers was associated with an increased risk of childhood ALL (OR=1.48; 95% CI: 1.01-2.16); in multivariable analyses, the OR for chlorinated hydrocarbons was 2.28 (95% CI: 0.97-5.37) while the ORs were close to one for aromatic hydrocarbons, glycol ethers, and other hydrocarbon mixtures. We also observed an increased risk of ALL with exposure to combustion exhaust/polycyclic aromatic hydrocarbons (PAHs) (ORs=1.70; 95% CI: 1.16-2.57, and 1.46; 95% CI: 0.94-2.26 with and without adjustment for chlorinated hydrocarbons, respectively). Moderately elevated risks of ALL were seen with exposure to metals, paints, and wood dust, although not statistically significant. An increased risk was reported for asbestos based on small numbers of exposed Latino fathers. No associations were reported between maternal exposures to any exposures and childhood ALL and AML.

Conclusions: Our data support associations between paternal occupational exposures to chlorinated hydrocarbons, combustion exhaust, metals, and possibly asbestos and the risk of ALL in the children of Latino fathers only.

Copyright © 2016 Elsevier Inc. All rights reserved.
Natural carcinogenic fiber and pleural plaques assessment in a general population: A cross-sectional study. C. Ledda, C. Pomara, M. Bracci, et al. 2016;150:23-29. PubMed · Publisher

Abstract

Natural carcinogenic fibers are asbestos and asbestiform fibers present as a natural component of soils or rocks. These fibers are released into the environment resulting in exposure of the general population. Environmental contamination by fibers are those cases occurred in: rural regions of Turkey, in Mediterranean countries and in other sites of the world, including northern Europe, USA and China. Fluoro-edenite(FE) is a natural mineral species first isolated in Biancavilla, Sicily. The fibers are similar in size and morphology to some amphibolic asbestos fibers, whose inhalation can cause chronic inflammation and cancer. The aim of the current study is to assess the presence and features of pleural plaques (PPs) in Biancavilla's general population exposed to FE through a retrospective cross-sectional study. All High-Resolution Computed Tomography (HRCT) chest scans carried out between June 2009 and June 2015 in Biancavilla municipality hospital site (exposed subjects) were reviewed. The exposed groups were 1:1 subjects, matched according to age and sex distributions, with unexposed subjects (n.1.240) randomly selected among HRCT chest scans carried out in a Hospital 30km away from Biancavilla. Subjects from Biancavilla with PPs were significantly more numerous than the control group ones (218 vs 38). Average age of either group was >60 years; the age of exposed subjects was significantly (p=0.0312) lesser than the unexposed group. In exposed subjects, in most PPs thickness ranged between 2 and 4.9cm(38%, n=83); while in unexposed ones PPs thickness was less than 2cm (55%, n=21). As to the size of PPs in exposed subjects, in most cases it ranged between 1cm and 24% of chest wall (53%, n=116); while in unexposed ones the size of PPs was lesser than 1cm (23%, n=58). Among exposed subjects, 36 cases (17%) PPs were detected with calcification, whereas in unexposed ones only three (8%) presented calcification. 137 lung parenchymal abnormalities were observed in exposed group; whereas, 12 lung parenchymal involvement were registered in unexposed subjects. The RR for PPs is 6,74 CI 95% (4,47-9,58) p<0,0001 in the exposed population. These findings, suggested the urge to extend the screening on the possible involvement of the respiratory tract to all Biancavilla's population, particularly in those aged more than 30. Besides, it seems essential to start indoor monitoring Biancavilla's municipality.

Copyright © 2016 Elsevier Inc. All rights reserved.
Risk of occupational exposure to asbestos, silicon and arsenic on pulmonary disorders: Understanding the genetic-epigenetic interplay and future prospects. P. Bhattacharjee, S. Paul, P. Bhattacharjee. 2016;147:425-34. Review PubMed · Publisher

Abstract

Background: Epidemiological studies suggest strong association of lung disorders with occupational exposure to asbestos, silicon and arsenic. The chronic occupational exposure primarily through inhalation results in adverse outcome on the respiratory tract which may also be fatal. Although several mechanisms have attributed towards these diseases; the molecular pathogenesis is still unknown.

Objective: In this review, we investigated the plausible molecular mechanism based on current research that may identify the genetic and epigenetic susceptibility of respiratory disorders upon such occupational exposures in humans.

Methods: We considered genetic variants and epigenetic alterations associated with pulmonary exposure hazards leading to asbestosis, silicosis and arsenicosis. Our review is stringently based on the literatures available through peer-reviewed articles mostly published in the last 10 years. Relevant search were conducted using keywords like "occupational lung disorders" along with "asbestos", "silicon" and "arsenic".

Results: Till September 2015, pubmed search yielded approximately 780 articles relating to asbestos exposure; 240 articles for silicon exposure and 60 articles for arsenic exposure. Extensive screening for genetic and epigenetic factors identified certain genes and related pathways that are important to determine the susceptibility of an individual towards such occupational exposure.

Conclusion: The link between genotype and phenotype and its association with disease susceptibility is very complex in nature due to several factors like person's environment, lifestyle and nutritional status. The epigenome is dynamic as well as reversible and can be reshaped further by certain dietary components throughout its life. In the present review, we have addressed the role of molecular pathogenesis of occupational lung diseases based on the genetic variability and epigenetic alterations and also attempted to highlight the promising aspect of dietary interventions to counter toxic outcomes upon occupational exposure to asbestos, silicon or arsenic.

Copyright © 2016 Elsevier Inc. All rights reserved.
Sheep lymph-nodes as a biological indicator of environmental exposure to fluoro-edenite. C. Ledda, C. Loreto, C. Pomara, et al. 2016;147:97-101. PubMed · Publisher

Abstract

A significantly increased incidence of pleural mesothelioma in Biancavilla (Sicily, Italy) has been attributed to exposure to fluoro-edenite (FE), a fibrous amphibole extracted from a local stone quarry. The lymph-nodes draining the pulmonary lobes of sheep grazing around the town were examined, to gain insights into fibre diffusion. The pasture areas of six sheep flocks lying about 3km from Biancavilla were located using the global positioning system. The cranial tracheobronchial and one middle mediastinal lymph-node as well as four lung tissue samples were collected from 10 animals from each flock and from 10 control sheep for light and scanning electron microscopy (SEM) examination. The lymph-nodes from exposed sheep were enlarged and exhibited signs of anthracosis. Histologically, especially at the paracortical level, they showed lymph-follicle hyperplasia with large reactive cores and several macrophages (coniophages) containing grey-brownish particulate interspersed with elements with a fibril structure, forming aggregates of varying dimensions (coniophage nodules). Similar findings were detected in some peribronchiolar areas of the lung parenchyma. SEM examination showed that FE fibres measured 8-41µm in length and 0.4-1.39µm in diameter in both lymph-nodes and lung tissue. Monitoring of FE fibres in sheep lymph-nodes using appropriate techniques can help set up environmental pollution surveillance.

Copyright © 2016 Elsevier Inc. All rights reserved.
Cancer incidence of Taiwanese shipbreaking workers who have been potentially exposed to asbestos. W.T. Wu, Y.J. Lin, H.S. Shiue, et al. 2014;132:370-8. PubMed · Publisher

Abstract

Background: Shipbreaking remains one of the most dangerous jobs worldwide. Shipbreaking workers are exposed to many hazardous chemicals, especially asbestos. Unfortunately, long-term follow-up studies of cancer incidence patterns in shipbreaking workers are lacking. This study examines whether there is an increased risk of cancer among male shipbreaking workers over a 24-year follow-up period.

Methods: 4155 male shipbreaking worker's information was retrospectively collected from Kaohsiung's Shipbreaking Workers Union database from 1985. The study cohort was linked to the Taiwan Cancer Registry from 1985 to 2008 for new cancer cases. The expected number of cancers for shipbreaking workers was calculated by using the age (5-year intervals) and calendar time-specific annual rates of cancer incidence with reference to the general population of Taiwan from 1985 to 2008. Standardized incidence ratios (SIRs) were calculated as relative risk estimates. The hazard ratio (HR) for cancer was calculated for the shipbreaking workers with Total Exposure Potential Scores for asbestos.

Results: After consideration of a 5-year latency period, an elevated incidence of overall cancer (N=368; SIR=1.13 (1.01-1.25)), oral cavity cancer (N=83; SIR=1.99 (1.58-2.46)), and trachea, bronchus, and lung cancers (N=53; SIR=1.36 (1.02-1.78)) was found among male shipbreaking employees. Moreover, mesothelioma cases were found in those who had the occupation of flame cutter. The high asbestos exposure group was associated with an increased SIR of developing overall cancer and oral cancer, whether we considered a 5-year or 10-year latency period.

Conclusion: Asbestos-related diseases, including lung cancer and mesothelioma, were seen in excess in these shipbreaking workers and some cases appeared to have a dose-dependent relationship. Preventative measures among male shipbreaking workers should be researched further.

Copyright © 2014 Elsevier Inc. All rights reserved.
Physicochemical and toxicological profiling of ash from the 2010 and 2011 eruptions of Eyjafjallajökull and Grímsvötn volcanoes, Iceland using a rapid respiratory hazard assessment protocol. C.J. Horwell, P.J. Baxter, S.E. Hillman, et al. 2013;127:63-73. PubMed · Publisher

Abstract

The six week eruption of Eyjafjallajökull volcano in 2010 produced heavy ash fall in a sparsely populated area of southern and south eastern Iceland and disrupted European commercial flights for at least 6 days. We adopted a protocol for the rapid analysis of volcanic ash particles, for the purpose of informing respiratory health risk assessments. Ash collected from deposits underwent a multi-laboratory physicochemical and toxicological investigation of their mineralogical parameters associated with bio-reactivity, and selected in vitro toxicology assays related to pulmonary inflammatory responses. Ash from the eruption of Grímsvötn, Iceland, in 2011 was also studied. The results were benchmarked against ash from Soufrière Hills volcano, Montserrat, which has been extensively studied since the onset of eruptive activity in 1995. For Eyjafjallajökull, the grain size distributions were variable: 2-13 vol% of the bulk samples were <4 µm, with the most explosive phases of the eruption generating abundant respirable particulate matter. In contrast, the Grímsvötn ash was almost uniformly coarse (<3.5 vol%<4 µm material). Surface area ranged from 0.3 to 7.7 m2 g(-1) for Eyjafjallajökull but was very low for Grímsvötn (<0.6 m2 g(-1)). There were few fibre-like particles (which were unrelated to asbestos) and the crystalline silica content was negligible in both eruptions, whereas Soufrière Hills ash was cristobalite-rich with a known potential to cause silicosis. All samples displayed a low ability to deplete lung antioxidant defences, showed little haemolysis and low acute cytotoxicity in human alveolar type-1 like epithelial cells (TT1). However, cell-free tests showed substantial hydroxyl radical generation in the presence of hydrogen peroxide for Grímsvötn samples, as expected for basaltic, Fe-rich ash. Cellular mediators MCP-1, IL-6, and IL-8 showed chronic pro-inflammatory responses in Eyjafjallajökull, Grímsvötn and Soufrière Hills samples, despite substantial differences in the sample mineralogy and eruptive styles. The value of the pro-inflammatory profiles in differentiating the potential respiratory health hazard of volcanic ashes remains uncertain in a protocol designed to inform public health risk assessment, and further research on their role in volcanic crises is warranted.

Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.
Occupational exposure to diesel and gasoline emissions and lung cancer in Canadian men. P.J. Villeneuve, M.É. Parent, V. Sahni, et al. 2011;111(5):727-35. PubMed · Publisher

Abstract

The International Agency for Research on Cancer classifies diesel exhaust as a probable human carcinogen; this decision is based largely from lung cancer evidence. Gasoline exhaust is classified as a possible carcinogen. Epidemiological studies are needed that improve upon some of the limitations of previous research with respect to the characterization of exposure, and the control for the potential confounding influence of smoking and other occupational exposures. Our objective was to investigate associations between occupational exposure to diesel and gasoline engine emissions and lung cancer. We used a case-control study design that involved men 40 years of age and older at the time of interview. Analyses are based on 1681 incident cases of lung cancer and 2,053 population controls. A self-reported questionnaire elicited a lifetime occupational history, including general tasks, and information on other potential risk factors. Occupational exposures to diesel and gasoline emissions, crystalline silica, and asbestos were assigned to each job held by study subjects by industrial hygienists who were blind to case-control status. Exposure metrics for diesel and gasoline emissions that were modeled included: ever exposure, cumulative exposure, and concentration of exposure. We found a dose-response relationship between cumulative occupational exposure to diesel engine emissions and lung cancer. This association was more pronounced for the squamous and large cell subtypes with adjusted odds ratios across the three increasing tertiles of cumulative lifetime exposure relative to those with no exposure of 0.99, 1.25, and 1.32 (p=0.04) for squamous cell carcinoma, and 1.06, 1.19, 1.68 (p=0.02) for large cell carcinoma. While the association with cumulative exposure to gasoline was weakly positive, it was not statistically significant. Our findings suggest that exposure to diesel engine emissions increases the risk of lung cancer particularly for squamous and large cell carcinoma subtypes.

Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

2000s

Cancer incidence and asbestos in drinking water, Town of Woodstock, New York, 1980-1998. M.L. Browne, D. Varadarajulu, E.L. Lewis-Michl, et al. 2005;98(2):224-32. PubMed · Publisher

Abstract

Late in 1985, asbestos contamination was discovered in the public water supply of the Town of Woodstock, Ulster County, New York. Contamination resulted from asbestos-cement pipes installed in the town water system in the mid to late 1950s and the corrosiveness of the local water. The New York State (NYS) Department of Health established the Woodstock Asbestos Exposure Registry (WAER) in 1986 to monitor rates of cancer among individuals who lived on the water supply between 1960 and 1985. Demographic, health, and residential information were collected on 2936 registrants. The follow-up period for observation of cancer was 1980-1998, consistent with the expected lag of 20-30+ years for development of asbestos-related cancers. The NYS Cancer Registry was used to ascertain cancer diagnoses. Standardized incidence ratios (SIRs) for gastrointestinal, respiratory, and total cancers were all approximately 1.00 or less and all 95% confidence intervals (CIs) included 1.00. For individual types of the gastrointestinal cancers, only the SIR for pancreatic cancer was marginally statistically significant at 2.19 (95% CI=1.00-4.16), based on a total of nine observed cases. The excess in pancreatic cancer occurred primarily among men (SIR=3.08; 95% CI=1.13-6.70) and was only slightly elevated among women (SIR=1.39; 95% CI=0.29-4.06). This association may be related to factors other than asbestos exposure such as occupation and lifestyle or to chance. No cases of mesothelioma were observed among WAER participants. There was no increase in incidence by latency or duration of residence on the water supply, but the ability to detect these trends is limited by small numbers and unknown dates of initial exposure. The general pattern of results did not demonstrate a likely link between exposure to asbestos in drinking water and cancer occurrence among participants in the WAER.
Ceiling (attic) dust: a "museum" of contamination and potential hazard. J.J. Davis, B.L. Gulson. 2005;99(2):177-94. PubMed · Publisher

Abstract

Ceiling or attic dusts provide an indirect measure of air pollution integrated over varying time periods. We undertook an investigation into the particle-size distributions and sources and exposure pathways of metals in ceiling dusts from 38 houses in the city of Sydney, Australia. The houses ranged in age from 4 to 106 years and were grouped into three settings: industrial, semi-industrial, and non-industrial. The main roof types were terracotta tile (n=23), cement tile (n=8), and corrugated iron (n=4), with two slate and one asbestos. Soils and rocks from the Sydney area were also analyzed to provide "background" values and allow the estimation of enrichment factors. The bulk of the dusts contained particles derived from soil of crustal origin and organic plant material, with an anthropogenic component estimated at up to 25%. Particle sizes from selected dust samples showed a bimodal distribution, and the volumes of fine dusts were 50% <63 microm, 30%<38 microm, and 7%<10 microm; the highest metal concentrations were in the finest fractions. The geometric mean concentrations of important anthropogenic-derived metals from the industrial setting were 17294 microg/g Zn, 1660 microg/g Pb, 111 microg/g Cr, 261 microg/g Cu, and 26 microg/g As. The metals Cd, Cu, Pb, Sb, and Zn were consistently higher in the industrial settings than in the other settings. Median regression analyses showed that there were significant differences in the urban setting for the metals Cd, Co, Ni, Pb, and Zn. Enrichment factors for metals in the dust from the industrial site houses compared with background soils and rocks from the Sydney area were As, x 5; Cr, x2; Co, x3; Cu, x 12; Pb, x10; Sb, x 26; and Zn, 596. For the three roof types of terracotta tile, cement, and iron, median regression analyses showed that there were no significant effects with respect to age. Median regression analyses for terracotta tile, cement tile, and corrugated iron roofs showed a "roof" effect for Cu and V. Significant correlations (P0.03) were observed between most of the metals As-Cd-Cu-Pb-Sb-Zn, especially from the industrial settings. Pathways of dust exposure in this study are classified as being passive or active based upon the probable route of dust infiltration. Ceiling dusts pose a probable health hazard if the dust is disturbed and allowed to plume within the living areas of a dwelling, thereby exposing the occupants, especially children, to elevated levels of metals and fine particulates. Modeling shows that exposure to the elevated levels of Pb in dust could give rise to blood lead concentrations exceeding current guidelines for the industrial and semi-industrial areas.
Respiratory impairment due to asbestos exposure in brake-lining workers. A. Franzblau, D.H. Garabrant. 2004;96(1):105-6; author reply 106-8. Letter · Comment PubMed · Publisher
Respiratory impairment due to asbestos exposure in brake-lining workers. M. Erdinç, E. Erdinç, G. Cok, et al. 2003;91(3):151-6. PubMed · Publisher

Abstract

There is extensive evidence that exposure to asbestos causes pulmonary parenchymal fibrosis, pleural disease, and malignant neoplasm in asbestos-exposed workers. However, few data concerning brake-lining workers are available in the literature. In this study, we aimed to assess the long-term effects of chrysotile asbestos exposure on lung function and the risk of asbestos-related diseases in brake-lining workers. Seventy-four asbestos-exposed workers who processed brake-lining products and 12 unexposed office workers were offered pulmonary function tests (spirometry and transfer factor) in 1992 and 1999. In 1999, the mean duration of asbestos exposure was 10.00+/-4.07 and 11.02+/-4.81 years (7-31 years) in nonsmoking and smoking asbestos workers, respectively. Transfer factor (T(L), CO) and transfer coefficient (K(CO)) decline were significant in the 7-year follow-up in both smoking and nonsmoking asbestos workers. However, lung function indices of the control group, whom were all current smokers; were also found to be decreased, including FEF(75), T(L), CO and K(CO). We found minimal reticular changes in 10 asbestos workers who were all current smokers, they underwent high-resolution computed tomography scans of the chest and we found that they had peribronchial thickening resulting from smoking. As a conclusion, even in the absence of radiographic asbestosis, T(L), CO and K(CO) may decrease after a mean 10-year duration of exposure to asbestos in brake-lining workers and this is more noticeable with cigarette burden.
Chemiluminescent detection of induced reactive oxygen metabolite production of human polymorphonuclear leucocytes by anthophyllite asbestos. T. Iwata, N. Kohyama, E. Yano. 2002;88(1):36-40. PubMed · Publisher

Abstract

Incidences of lung cancer and pleural plaque have been reported in relation to exposure to anthophyllite asbestos. To investigate the pathogenic mechanisms of anthophyllite, chemiluminescence (CL) detection of reactive oxygen metabolite (ROM) generation of human polymorphonuclear leucocytes (PMN) stimulated by anthophyllite asbestos was determined and compared with that of other asbestos and mineral fiber samples. When anthophyllite fiber sample was mixed with the luminol-primed PMN, high levels of CL which exhibited a specific time course characterized by two separate peaks were induced. The CL induced by anthophyllite sample was greater than that induced by chrysotile, crocidolite, and amosite asbestos. We further investigated the two peaks of CL using specific inhibitors of signal transduction mechanisms. The two peaks of CL by anthophyllite sample were different in sensitivity to cytochalasin B and genistein; the former relates to the cytoskeleton-dependent mechanism and the latter has been shown to inhibit tyrosine kinase, which resides in the pathway to cause PMN activation. The strong ROM reaction of PMN by anthophyllite suggests that the surface characteristics of the fiber may participate in the pathogenic mechanisms of anthophyllite asbestos.

1990s

An overview of the role of mineral solubility in silicosis and asbestosis. G. Erdogdu, V. Hasirci. 1998;78(1):38-42. Review PubMed · Publisher

Abstract

Asbestosis and silicosis are fibrotic diseases initiated by the inhalation of silica-containing dusts, asbestos and quartz. There are various approaches for explaining the causes of these diseases. At present, our knowledge on the matter indicates that silicic acid dissolved from these minerals, contact between macrophages and minerals, highly reactive and oxidative species formed on the mineral surface, and lysosomal enzymes released upon engulfment of particulate mineral of appropriate size all contribute to various extents to the initiation of fibrosis. Among these mineral solubility seems to have a substantial contribution as a causative factor.
Lung cancer risk and workplace exposures in black men and women. J.E. Muscat, S.D. Stellman, J.P. Richie, et al. 1998;76(2):78-84. PubMed · Publisher

Abstract

There are little data on workplace exposures and lung cancer risk in blacks. An ongoing case-control study of lung cancer that included 550 black men and women with lung cancer and 386 age-matched controls was examined by reported occupational exposures and job titles. In men, significant associations were observed with reported exposure to asbestos [odds ratio (OR), 1.8; 95% confidence intervals (CI) 1.03-3.1] and coal dust (OR, 2.8; 95% CI 1.1-7.0). Elevated but nonsignificant risks of 1.4 or more were detected for the following occupations: police/security guards, farmers/farm workers, laborers, and motor-vehicle drivers. In women, nonsignificant increased risks were found with reported exposure to paint (OR, 1.8) and gas fumes (OR, 4.9). Women employed as farmers/farm workers and building maintenance workers had elevated but nonsignificant risks.
A case-control study of lung cancer mortality in six Gila Basin, Arizona smelter towns. G.M. Marsh, R.A. Stone, N.A. Esmen, et al. 1997;75(1):56-72. PubMed · Publisher

Abstract

To investigate factors related to lung cancer mortality in six Arizona copper smelter towns, we identified 185 lung cancer cases and two matched controls per case from decedent residents during 1979-1990. Detailed information on lifetime residential, occupational, and smoking history was obtained by structured telephone interviews with knowledgeable informants. Interviews were completed for 82% of 183 eligible cases and 88% of the targeted number (366) of controls. Estimated historical environmental exposures to smelter emissions, based on atmospheric diffusion modeling of measured SO2 concentrations, were linked with residential histories to derive individual profiles of residential exposure. Occupational histories were characterized by potential exposure to smelter emissions, asbestos, and ionizing radiation. Conditional logistic regression was used to compare study factors in cases and controls with adjustment for potential confounding factors: gender, Hispanic ethnicity, and smoking. In overall and gender-specific analyses, no statistically significant associations were observed between lung cancer risk and any of the measures of residential exposure to smelter emissions considered (town of residence at time of death, highest level of exposure, and duration or cumulative exposure above background levels), or any of the estimated occupational exposures (definite or potential asbestos, potential ionizing radiation, definite or potential smelter). Among male residents of some, but not all, towns, there was some evidence of a positive association between lung cancer risk and reported copper smelter-related employment (reported as definite), with the highest risk observed for Miami, Arizona. This study provided little evidence of a positive association between lung cancer mortality and residential exposure to smelter emissions. Specific factors associated with the apparent heterogeneity in lung cancer risk across study towns cannot be identified in this community-based study.
Cellular mechanisms of reactive oxygen metabolite generation from human polymorphonuclear leukocytes induced by crocidolite asbestos. T. Ishizaki, E. Yano, P.H. Evans. 1997;75(2):135-40. PubMed · Publisher

Abstract

In our previous study, we demonstrated that reactive oxygen metabolites (ROM) generation from phagocytic cells may be involved in the carcinogenic mechanism of crocidolite asbestos. In the present study, the mechanism of human polymorphonuclear leukocytes (PMN) to generate ROM by crocidolite was investigated using verapamil, a calcium channel inhibitor; staurosporine, a NADPH oxidase inhibitor; and cytochalasin B (CB), an inhibitor of phagocytosis. The results indicate that whereas verapamil and staurosporine inhibited the crocidolite-induced ROM generation from PMN dose-dependently, CB caused an enhancement. We conclude that crocidolite-induced ROM generation involves a cell surface reaction due to influx of extracellular calcium through calcium channels and the activation of NADPH oxidase on the PMN cell membrane. This hypothesis was indirectly supported by dose-dependent enhancement of the ROM generation by CB, as CB increases calcium ion permeability in PMN. However, as in our previous studies, the time course of the ROM generation and the cell type difference suggested that ROM were also generated intracellularly from PMN due to phagocytosis of crocidolite. In conclusion, our evidence indicates that ROM generation from PMN by crocidolite involves cellular mechanisms related both to direct cell surface membrane interactions, together with an apparent phagocytic-dependent process.
Effect of kerosene and its soot on the chrysotile-mediated toxicity to the rat alveolar macrophages. J.M. Arif, S.G. Khan, I. Ahmad, et al. 1997;72(2):151-61. PubMed · Publisher

Abstract

In order to examine the pulmonary toxicity of kerosene oil and its combustion product (soot) in asbestos-exposed rats, various biochemical and chemical parameters were assayed. Treatment of rats with a single intratracheal dose of chrysotile asbestos (5 mg) and kerosene (50 microliters) or its soot (5 mg) in combination led to an increased number of pulmonary alveolar macrophages (PAM), elevated levels of hydrogen peroxide, and thiobarbituric acid-reacting substances, alterations in the activities of primary (glutathione peroxidase and catalase) and secondary (glutathione reductase and glucose-6-phosphate dehydrogenase) endogenous antioxidant enzymes, and depletion in the levels of glutathione in PAM compared to the chrysotile, kerosene, or soot alone. These changes may indicate the generation of oxidative stress in the macrophages. The resulting oxidative stress may be subsequently critical in collapsing the cellular membrane, which may change the cell membrane permeability and may also damage the phagolysosomal membrane, thereby releasing the membrane bound enzymes as indicated by an increased leakage of intracellular acid phosphatase and lactate dehydrogenase. The injury to macrophages may trigger events that lead to lung fibrosis and/or malignancies in the exposed animals. This study may be helpful in understanding the etiology of certain clinical and pathological disorders in the population exposed simultaneously to both asbestos and kerosene or its combustion products.
Mesothelioma incidence and community asbestos exposure. M. Berry. 1997;75(1):34-40. PubMed · Publisher

Abstract

This study evaluates the environmental, nonoccupational component of mesothelioma incidence among persons living in Manville, Somerset County, New Jersey, the location of the largest asbestos manufacturing plant in North America. Prior to removal of occupational cases, residents of Manville had an average annual (1979-1990) mesothelioma rate of 636 male cases and 96 female cases per million population, about 25 times higher than average state rates. Somerset County had 143 diagnosed mesothelioma cases reported to the population-based. New Jersey State Cancer Registry from 1979 through 1990. Cases were removed from the analysis when their "usual employment" was reported as being at the asbestos plant, as evidenced through union lists or occupational information from either the Cancer Registry or mortality records. Standardized incidence ratios (SIRs) were computed for residents of Manville and Somerset County (less the Manville population) by sex. New Jersey mesothelioma rates less the Somerset County contribution, 1979-1990, were used to generate the expected number of cases. The SIRs for Manville males and females were respectively 10.1 [95% confidence interval (CI): 5.8-16.4] and 22.4 (95% CI: 9.7-44.2). Male and female Somerset County mesothelioma incidence rates were 1.9 (95% CI: 1.4-2.5) and 2.0 (95% CI: 1.0-3.6). This record-based approach demonstrates a strong relationship between past asbestos exposure from living in Manville and eventual development of mesothelioma. The use of methods in this study may be helpful in evaluating hazards of other known occupational carcinogens found in community settings.
Cigarette tar promotes neutrophil-induced DNA damage in cultured lung cells. P. Leanderson, C. Tagesson. 1994;64(2):103-11. PubMed · Publisher

Abstract

We have investigated the ability of aqueous cigarette tar extracts to promote human polymorphonuclear leukocyte (PMNL)- and hydrogen peroxide (H2O2)-induced DNA single-strand breaks (DNA-SSB) in cultured human lung cells. Tar extract itself did not cause any DNA-SSB formation, whereas PMNL (activated with phorbol myristate acetate (PMA)) and H2O2 both caused a small but significant DNA-SSB formation on their own. On the other hand, if cells were first treated with tar extract and then exposed to PMA-activated PMNL or H2O2, the DNA-SSB formation increased considerably. Pretreatment with iron-loaded tar extracts caused a greater increase after PMNL exposure than pretreatment with regular tar extracts. No DNA-SSB formation was found if catalase was present during the PMNL exposure, indicating that H2O2 was important for the PMNL-induced DNA damage. These findings suggest that cigarette tar promotes neutrophil-induced DNA damage in human lung cells and that this effect can be further potentiated by iron. This can be of importance in explaining the carcinogenic effects of cigarette smoking and the increased risk of lung cancer among asbestos workers and iron miners who smoke.
Crocidolite-induced reactive oxygen metabolites generation from human polymorphonuclear leukocytes. T. Ishizaki, E. Yano, N. Urano, et al. 1994;66(2):208-16. PubMed · Publisher

Abstract

In order to study the mechanism of carcinogenicity of crocidolite asbestos, we have investigated the species of reactive oxygen metabolites (ROM) induced by crocidolite from human polymorphonuclear leukocytes (PMN) utilizing both an electron spin resonance (ESR) spin trapping method with 5,5-dimethyl-1-pyrroline N-oxide (DMPO), and a luminol-dependent chemiluminescence (CL) method. The present study confirms the generation of OH. from human peripheral blood PMN stimulated by UICC crocidolite utilizing ESR. In addition, PMN incubated with 25-400 micrograms/ml of crocidolite produced CL, the intensity of CL increasing in a dose-dependent manner. Superoxide dismutase, catalase, and dimethyl sulfoxide, which are scavengers of O2-, H2O2, and OH., respectively, inhibited the production of crocidolite-stimulated CL from PMN, also in a dose-dependent manner. Sodium azide, an inhibitor of myeloperoxidase (MPO) to produce OCl-, also inhibited CL production. These results suggest the involvement of O2-, H2O2, OH., and OCl- in the production of CL by crocidolite-stimulated PMN. In conclusion, it is proposed that OH. is a key ROM species in the mechanism of crocidolite-induced carcinogenesis.
Ferruginous bodies as markers of environmental exposure to inorganic particles: experience with 270 autopsy cases in Mexico. F.J. Arenas-Huertero, M. Salazar-Flores, A.R. Osornio-Vargas. 1994;64(1):10-7. PubMed · Publisher

Abstract

Ferruginous bodies (FB) were quantified in lung digests from 270 autopsy cases over 20 years of age. The cases were autopsied in three different hospitals of the Secretaria de Salud, Mexico, DF. Two hundred seventy samples of peripheral lung tissue were digested in commercial bleach, and all morphologic types of ferruginous bodies were quantified. The results showed that numbers of ferruginous bodies per gram of dry tissue increased over the years: 4.2 FB/g in cases from 1975 to 42.5 FB/g in cases from 1988 (r = 0.86). Higher counts of ferruginous bodies were seen in males, smokers, and Mexico City dwellers. However, more than 70% of them presented less than 100 FB/g. Our study demonstrates that most of our cases had a nonoccupational exposure to fibers.
Free radical generation during interaction of chrysotile asbestos with natural compounds. T.B. Suslova, Z.P. Cheremisina, L.G. Korkina. 1994;66(2):222-34. PubMed · Publisher

Abstract

Free radical generation was found after the addition of some natural biological substances (adrenaline, ascorbate, ubiquinone Q9, etc.) to a chrysotile asbestos suspension. This was detected by the chemiluminescent method with lucigenin as an indicator. The detailed study of the chemiluminescent reaction in the adrenaline-chrysotile system indicated that the reaction required hydroxyl ions, which arose in the chrysotile suspension, and was accompanied by a superoxide radical formation. At the same time, the radical production was very low in suspensions of amphybole asbestos, talc, and quartz, which could not alkalinize the water medium. On the basis of these results, it may be concluded that chrysotile has a unique ability to generate free radicals upon interaction with some biological molecules in a water medium. This fact may explain the great carcinogenicity of chrysotile. The injection of cigarette smoke solution into chrysotile (but not into amphibole asbestos or talc) suspension induced intensive chemiluminescence. This suggests that smoke aggravates the effect of chrysotile on human health by increasing free radical generation on the surface of the fibers.
Mesothelial cell injury caused by pleural leukocytes from rats treated with intratracheal instillation of crocidolite asbestos or Corynebacterium parvum. X.Y. Li, D. Lamb, K. Donaldson. 1994;64(2):181-91. PubMed · Publisher

Abstract

The pleural and peritoneal mesothelium is a major target in asbestos exposure where mesothelial cell proliferation, exfoliation, and neoplasia have been reported in workers and experimental animals. The objective of this study was to determine the role of pleural leukocytes in mesothelial cell damage caused by asbestos exposure. We therefore investigated detachment and lysis injury to mesothelial cells in vitro induced by leukocytes lavaged from the pleural space of rats exposed, by intratracheal instillation, to crocidolite asbestos. Our studies revealed that normal pleural leukocytes were composed of macrophages, lymphocytes, eosinophils, and mast cells. This population showed a small but significant recruitment of mast cells and eosinophils 3 to 14 days after instillation of crocidolite asbestos; there were also modestly increased levels of macrophages present 30 days after low doses of asbestos. One day after intratracheal instillation of 5 mg crocidolite asbestos, the pleural leukocytes caused detachment injury to mesothelial cells in vitro. This injury was markedly reduced 3 days after asbestos exposure and was undetectable by Day 14. One month after instillation of asbestos, despite doses of asbestos from 0.5 to 5 mg, pleural leukocytes showed no ability to injure mesothelial cells in vitro. In a parallel study, pleural inflammation was induced by intratracheal instillation of heat-inactivated Corynebacterium parvum. Transient mesothelial cell-detaching injury was again expressed by pleural leukocytes 1 day after C. parvum instillation. This was likely related to an increase in the percentage of neutrophils present on this day. These results show that a single administration of crocidolite asbestos, intratracheally, leads to transient activation of pleural leukocytes in terms of the ability of these cells to detach mesothelial cells from matrix. This finding implies that mesothelial cell proliferation and exfoliation found in individuals exposed to asbestos may result from persistent stimulation of pleural leukocytes caused by the continuous presence of asbestos in the lung.
A radioactive tracer technique to determine in vivo the number of fibers in the lungs of rats following their administration by intratracheal instillation. A. Morgan, C.G. Collier, K.J. Morris, et al. 1993;63(2):182-90. PubMed · Publisher

Abstract

A radioactive tracer technique is described which enables the total number of fibers present in the lungs of rats to be estimated following administration of the fibers by intratracheal instillation. The glass fiber used in the study was irradiated with thermal neutrons to induce radioactive 24Na. A suspension of the radioactive fiber was administered to eight rats by intratracheal instillation and to two additional rats by intraesophageal instillation. The 24Na radioactivity in the rats was counted in vivo at 24 and 48 hr after administration, after which they were killed. The amounts of fiber in the lungs, in the gastrointestinal tracts, and excreted in feces were estimated radiometrically. On average 93% of the administered fiber was accounted for. The lungs were digested with sodium hypochlorite solution and aliquots of the resulting digest filtered through membrane filters which were clear for examination by phase-contrast optical microscopy (PCOM). The numbers of fibers in the lungs, estimated by PCOM, were well correlated with the in vivo counting rates at 48 hr, indicating that the latter can be used to provide an accurate index of the number of fibers retained in the lung at that time.
Activation of UICC crocidolite: the effect of conversion of some ferric ions to ferrous ions. M. Gulumian, D.J. Bhoolia, R.S. Du Toit, et al. 1993;60(2):193-206. PubMed · Publisher

Abstract

Asbestos fibers catalyze the generation of oxygen-centered radicals in the presence of oxygen or hydrogen peroxide. The amount of iron in asbestos fibers, its oxidation state, and its availability to specific chelating agents determine their ability to catalyze the aforementioned reactions. In the present study, the activation of UICC crocidolite was achieved by converting some of the ferric ions into ferrous ions. The activation process did not interfere with the size distribution, surface area, or crystal structure of these fibers. Although oxygen-centered radicals generated and lipid peroxidation produced by asbestos fibers are reported to play an important role in their toxicity, factors such as size, surface area, and durability are considered to be crucial determinants of fiber toxicity and carcinogenicity. The employment of the activated crocidolite in animal experiments to help further elucidate the importance of oxygen free radicals and lipid peroxidation in fiber-induced diseases is therefore proposed.
Pulmonary function in asbestosis and asbestos-related pleural disease. A. Miller. 1993;61(1):1-18. Review PubMed · Publisher

Abstract

This review begins with the classic physiologic syndrome of interstitial lung disease (ILD) described in established asbestosis in the 1950s: reduced VC and pulmonary compliance, maintenance of airflow (measured indirectly), decreased diffusing capacity (a laborious undertaking in those years), and hyperventilation, increased dead space (VD/VT), and desaturation on exercise. Small airways dysfunction (SAD) was recognized in the 1960s and 1970s as the physiologic counterpart of the early peripheral bronchiolar inflammatory and fibrotic narrowing reported in experimental animals and in asbestos workers. SAD is nonspecific and is often overshadowed by more severe obstruction caused by smoking or by the countervailing effects of increased lung recoil caused by interstitial fibrosis. Airtrapping secondary to SAD may explain some of the reduction in VC in asbestos exposed workers whose FEV1/FVC is normal. There may be a greater frequency of obstructive airways disease in asbestos workers who smoke than in other smokers, suggesting an interaction between these two noxious inhalants. An interaction is seen in the greater frequency and severity of radiographic asbestosis in smokers at equivalent durations of exposure and in the greater reduction in FVC in smokers at equivalent ILO profusion scores. The functional importance of PT is well documented by lower values for FVC at equivalent profusions of parenchymal disease. This is true of circumscribed PT but much more so of diffuse PT, which can occasionally result in ventilatory failure and death. Incremental exercise testing often reveals evidence of excessive ventilation and abnormal gas exchange (VD/VT) attributable to ILD, when standard tests of pulmonary function and chest radiography are normal. These abnormalities help explain dyspnea in such patients.
Pulmonary response, in vivo, to silicon carbide whiskers. G.L. Vaughan, S.A. Trently, R.B. Wilson. 1993;63(2):191-201. PubMed · Publisher

Abstract

Fischer rats were exposed to silicon carbide whiskers (SiCW), boron carbide whiskers (BCW), silicon carbide platelets (SiCP), or crocidolite asbestos separately administered by intratracheal instillation. SiCW proved to be the most toxic material within the test group. Dramatic increases in alveolar macrophage populations within 1 week of exposure to SiCW persisted for at least 28 days, evidence of the chronic inflammation observed in necropsies during the first months of the study. The most common finding in histological preparations of tissues taken from animals 18 months after exposure to SiCW was a high incidence (frequency > 0.85) of multiple pulmonary granulomas which occasionally occluded airways. Lesions associated with crocidolite were similar to those found with SiCW. Equivalent treatment with BCW and SiCP produced no significant histological changes within 18 months of exposure.
Respiratory findings among millwright and machinery erectors: identification of health hazards from asbestos in place at work. A. Fischbein, J.C. Luo, M. Lacher, et al. 1993;61(1):25-35. PubMed · Publisher

Abstract

Asbestos-associated diseases are prevalent in the construction trades primarily because of the previously widespread use of asbestos-containing insulation materials. Workers in metal-related trades, employed at construction sites and power facilities, but who do not routinely handle such materials as part of their work, may also be at risk for significant asbestos exposure. In order to evaluate such risk, a clinical field survey was conducted of 110 millwright and machinery erectors from the New York metropolitan area. A high prevalence of chest roentgenologic abnormalities was found. Forty-nine (44.5%) of the examined workers had pleural abnormalities consistent with asbestos-induced effects. Eighteen workers showed evidence of unilateral pleural thickening. Duration from onset of employment was significantly longer for those with pleural abnormalities (mean 32.3 years) as compared to those with normal chest radiographs (mean 18.5 years). Thirteen workers (11.8%) had radiographic signs of interstitial lung disease. The workers with pleural abnormalities had lower mean values of restrictive and obstructive lung function parameters than those with normal pleura. Multivariate and logistic regression analyses demonstrated association between duration of employment in the millwright trade and pleural abnormalities which was independent of smoking status. These findings suggest that millwright and machinery erectors employed in work environments where there is potential for primarily indirect exposure to airborne asbestos-containing dust are at risk for adverse effects from such exposure.
Transfection of human mesothelial cells mediated by different asbestos fiber types. L. Gan, E.F. Savransky, T.M. Fasy, et al. 1993;62(1):28-42. PubMed · Publisher

Abstract

Several different asbestos fiber types mediate transfection of human mesothelial cells by exogenous DNA. We have employed the human MeT-5A mesothelial cell line, which allows the use of DNA replication as an assay for entry of DNA when plasmids bearing the SV40 origin of replication are used for transfection. We find that Canadian chrysotile, Calidria chrysotile, amosite, and crocidolite are each capable of introducing plasmid pSVod DNA into MeT-5A cells followed by subsequent replication of a fraction of the plasmid DNA. A significant fraction of the input plasmid DNA associated with the cells in the presence of asbestos is fragmented, and this fragmentation is particularly evident with crocidolite. Each of the fiber types is highly cytotoxic for the MeT-5A cells, and these cells actively accumulate the added fibers from the surrounding environment as visualized by phase-contrast microscopy. MeT-5A cells were transfected at higher efficiency with calcium phosphate than were several other primate cell lines. Calcium phosphate, however, did not induce fragmentation of the input plasmid DNA. Compared with several different mineral agents, including glass fibers, kaolin, and talc, Calidria chrysotile fibers were most effective at mediating transfection of the MeT-5A cells. Results provide a mechanism by which transfection can contribute to mutagenicity of asbestos fibers and indicate that this mechanism can operate in human mesothelial cells.
A radiographic survey of public school building maintenance and custodial employees. H.A. Anderson, L.P. Hanrahan, D.N. Higgins, et al. 1992;59(1):159-66. PubMed · Publisher

Abstract

Analyses of radiographs from a cohort of 457 school maintenance and custodial workers (90 had no employment other than at a school) demonstrated an increased prevalence of abnormalities consistent with asbestos-caused disease. Pleural abnormalities predominated (24 of 29). The abnormalities could not be explained by occupational asbestos exposures which may have occurred prior to school employment. Abnormality prevalence ranged from 1.7% among those with less than 10 years to 37% among those with 30 or more years of public school employment. Laborers and skilled tradesmen with more than 20 years of school employment had a higher prevalence of abnormality (40 and 28%) than the building engineers (14%). In order to ensure that future asbestos exposure and disease risk is minimized in buildings constructed with asbestos-containing materials (ACM), implementation of asbestos hazard identification and abatement must include a rigorous operations and maintenance program. Control of asbestos exposure from in-place ACM is a public health priority.
A retrospective mortality cohort study of chrysotile asbestos products workers in Tianjin 1972-1987. W.N. Cheng, J. Kong. 1992;59(1):271-8. PubMed · Publisher

Abstract

The mortality rate of a cohort of asbestos workers was investigated in Tianjin, China, between January 1, 1972, and December 31, 1987. The cohort consisted of 662 males and 510 females, employed in asbestos textiles, friction material, and asbestos cement manufacturing. A statistically significant excess mortality was observed for lung cancer in both males and females (SMR 278 and 427, respectively). An increasing trend in SMR was observed with increasing intervals of exposure as well as with increasing exposure level. A synergistic effect was seen between asbestos exposure and cigarette smoking regarding lung cancer. The ratio of smoking and nonsmoking lung cancer death rates was virtually the same in asbestos and in nonasbestos workers. This ratio was approximately 1.6, a value much less than that reported in other countries. This low ratio appears to reflect the fact that many nonsmokers were in fact passive cigarette smokers. Second, it reflects the fact that most smokers smoked hand-rolled tobacco, since manufactured cigarettes did not become popular in China until 1965. These data confirm the hazards of asbestos exposure in developing countries.
Advances in lung cancer?. A.S. Teirstein. 1992;59(1):145-9. PubMed · Publisher

Abstract

Selikoff was among the first to emphasize the etiologic role of cigarette smoking and asbestos exposure in lung cancer. Recent reports suggest that aggressive chemotherapy and radiotherapy combined with surgery have improved the prognosis in lung cancer. The outcome of 100 patients with non-small-cell lung cancer (NSCLC) seen in 1979-1980 was compared with the outcome of 100 patients seen in 1989-1990. The two groups consisted of consecutive patients with proven NSCLC who were referred to a pulmonary consultant. In 28 of the earlier patients and 38 of the later group the cancers were completely resectable. Only 12 of the 1979-1980 group have been cured of their cancer, while 25 of the 1989-1990 are free of cancer during the less than 2-year follow-up period. It can be assumed that this number will diminish with time. Current treatment of NSCLC with surgical resection, chemotherapy, and radiotherapy has done little to improve the prognosis of lung cancer in the past 10 years. As stressed by Selikoff, the best available current method for control of lung cancer is prevention.
Asbestos in organs and placenta of five stillborn infants suggests transplacental transfer. A.K. Haque, M.G. Mancuso, M.G. Williams, et al. 1992;58(2):163-75. PubMed · Publisher

Abstract

Digests of lungs, liver, and placenta from five stillborn infants of 22 to 38 weeks gestational age were examined for asbestos and other fibers using light and electron microscopy, energy dispersive X-ray analysis, and selected area diffraction analysis. Uncoated chrysotile asbestos fibers were found in the digests of at least one of the three tissues examined from each stillborn infant. The asbestos fiber burdens ranged from 71,000 to 357,000 fibers/g wet tissue. Most of the fibers were small, with the mean length ranging from 0.83 to 2.53 microns. While appreciable numbers of uncoated chrysotile fibers were present, no coated asbestos fibers were found in any of the stillborns. Both coated and uncoated nonasbestos fibers were found in at least one of the tissue digests of all five stillborns. The uncoated nonasbestos fibers were characterized as aluminum silicates, diatomaceous earth fragments, or other fibers. The coated nonasbestos fibers or ferruginous bodies were consistent with being formed on diatomaceous earth fragments, black carbon cores, or sheet silicate cores. Since the placenta is the only route of communication between the fetus and the outside environment, our findings strongly suggest a transplacental transfer of asbestos and other fibers in humans.
Asbestos-containing materials in New York City buildings. P. Lundy, M. Barer. 1992;58(1):15-24. PubMed · Publisher

Abstract

The New York City Department of Environmental Protection (DEP) carried out a survey to assess the public's risk of exposure in buildings to in-place asbestos-containing materials (ACM). Data regarding the presence of in-place asbestos and the potential for exposure to asbestos were collected in 886 buildings from 16 different building categories in New York City. Overall 68% of the buildings in New York City contain ACM. The estimated total amount of ACM in the city is 323 million ft2 most of which is thermal system insulation. Overall, 16% of all ACM had greater than 10% of its surface damaged and another 68% of ACM had some, but less than 10% of its surface damaged. About half of all ACM is in mechanical spaces within buildings. On the basis of results of the survey, buildings in New York City were prioritized for management and an in-place management bill was introduced into the New York City Council.
Asbestos-related hazards in developing countries. B.S. Levy, A. Seplow. 1992;59(1):167-74. Review PubMed · Publisher

Summary

The authors examined asbestos hazards in developing countries and responses to them. They reviewed published reports, presented a questionnaire survey, summarized ongoing research and described the International Labor Organization (ILO) asbestos convention. Cited studies included a Thai survey that found a 5.2% prevalence of asbestosis and asbestos-related diseases among 1013 workers in 24 factories, and a Thai study in which 109 (33%) of 330 randomly autopsied lungs contained asbestos bodies. In summer 1991 the authors surveyed occupational and environmental health specialists from 13 developing countries. Roofing materials and brake linings were each named as leading occupational sources by respondents from 8 countries. Nine countries had workplace asbestos standards, but in 7 of these respondents said enforcement was lenient or absent. Only 3 countries had environmental asbestos standards, and 10 had workers' compensation laws. Of 73 responses on the feasibility of specific workplace preventive measures, 63 (86%) were ranked "probable" or "possible." Five respondents rated asbestos exposure a high priority, five a low priority and three not a priority. A mid-1990 inventory identified 15 ongoing research projects concerned at least in part with asbestos. As of 1991, only 11 countries had ratified ILO Convention 162 (1986). The authors concluded that asbestos exposure is a widespread hazard in developing countries. They called implementation of preventive measures essential to avoid a worldwide catastrophe of asbestos-related health effects.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.
Comparative quantitative evaluation of pleural fibrosis and its effects on pulmonary function in two large asbestos-exposed occupational groups--insulators and sheet metal workers. R. Lilis, A. Miller, J. Godbold, et al. 1992;59(1):49-66. PubMed · Publisher

Abstract

Two large (N = 1584 and N = 1330) population groups of workers exposed to asbestos as insulators (I) or sheet metal workers (SM) were compared. Prevalence rates of radiographic changes including pleural fibrosis (circumscribed and diffuse) were found to be much higher in I than SM. An integrative index of pleural fibrosis (INDEX) showed similar distribution patterns in the two groups; the effect of INDEX on FVC% predicted was more marked in insulators. Factors that could contribute to this difference are thought to be the higher prevalence of interstitial pulmonary fibrosis (probably including that which is not yet radiologically detectable) in I than in SM, the possibility of more extensive pleural fibrosis in areas not accessible to the standard chest X ray (and thus not affecting INDEX) and a higher proportion of diffuse pleural fibrosis in the I group.
Deposition, clearance, and translocation of chrysotile asbestos from peripheral and central regions of the rat lung. P.G. Coin, V.L. Roggli, A.R. Brody. 1992;58(1):97-116. PubMed · Publisher

Abstract

We investigated the pulmonary deposition, clearance, and translocation of chrysotile asbestos in the context of our previously developed model of asbestosis in the rat. Adult male rats were exposed for 3 hr to an aerosol of chrysotile asbestos. Subgroups were sacrificed up to 29 days postexposure and the lungs of the animals fixed. Peripheral and central regions of the left lung were resected, digested, and analyzed for fiber content by scanning electron microscopy. Pulmonary deposition did not differ between peripheral and central regions. There was no evidence of translocation of fibers from central to peripheral regions. The average diameter of retained fibers decreased over time, consistent with longitudinal splitting. The average length of retained fibers increased over time, consistent with slower clearance of longer fibers. We employed a novel counting scheme to ensure accurate fiber number measurements, allowing the calculation of clearance rates for fibers 0.5 to greater than or equal to 16 microns in length. Fibers of length greater than or equal to 16 microns were cleared slowly, if at all. These findings could have important implications for the pathogenesis of asbestos-related pleural disease. Many fibers are deposited in the peripheral region, and the longest (greater than or equal to 16 microns) will persist there for extended periods.
Induction of chromosomal aberrations in bone marrow cells of asbestotic rats. N. Fatma, S.G. Khan, M. Aslam, et al. 1992;57(2):175-80. PubMed · Publisher

Abstract

In the present study, cytogenetic effects of Indian chrysotile asbestos in rat bone marrow cells after 290 days of intratracheal inoculation (5 mg dust/0.5 ml normal saline), when it develops massive pulmonary fibrosis, were investigated. The pulmonary fibrosis was confirmed by both histopathological studies and increased collagen content in the lung of the treated animals. In the asbestotic rats a significant increase in chromosomal aberrations was recorded and a decrease in mitotic index of bone marrow cells. The types of chromosomal aberrations in these cells were chromatid gaps and breaks. The results indicate the significant cytogenetic changes in the bone marrow cells of asbestotic rats and also suggest that these changes directly or indirectly may be one of the biological events involved in eliciting the asbestos-mediated toxic responses.
Occupational exposure to asbestos and urinary bladder cancer. R. Molinini, L. Paoletti, M. Albrizio, et al. 1992;58(2):176-83. Case report PubMed · Publisher

Abstract

By the use of transmission electron microscopy (TEM) and energy dispersion spectrometry the amount (mean value mean = 191 +/- 94 fibers/mg of tissue) and the type (chrysotile and tremolite) of asbestos fibers have been determined in tissue samples of four bladder cancer patients affected by pulmonary asbestosis, working in the same plant producing asbestos-cement pipes and boards. Similar measurements were carried out on samples of bladder cancers of eight control patients not professionally exposed to asbestos. Only five of them also revealed chrysotile fibers (mean = 151 +/- 196 fibers/mg of tissue). The paucity of the study and control cases and the small quantitative difference between them regarding the presence of infraneoplastic asbestos fibers does not consent us to hypothesize a causal relationship between tumor and occupational exposure.
Tumor incidence was not related to the thickness of visceral pleural in female Syrian hamsters intratracheally administered amphibole asbestos or manmade fibers. S. Adachi, K. Kawamura, K. Kimura, et al. 1992;58(1):55-65. PubMed · Publisher

Abstract

Histological observations were performed on female Syrian hamsters 2 years after the intratracheal administration of amphibole asbestos, amosite, and crocidolite to evaluate the tumorigenicity of six types of fine manmade fibers (reported previously). A mesothelioma and a lung tumor were induced in 20 animals administered amosite, but no tumors were found in the crocidolite group. Because this incidence is not higher than that of manmade fibers, such as basic magnesium sulfate fiber [9 tumor-bearing hamsters in 20 hamsters (9/20)], metaphosphate fiber (5/20), calcium sulfate fiber (3/20), and fiberglass (2/20), it is suggested that some types of manmade fibers have a greater ability than asbestos to induce tumors. Moreover, as a specific observation in manmade fiber groups, tumors were induced at intracelial organs rather than at the pleural cavity. On the other hand, the average thickness of visceral pleura was higher in all asbestos and manmade fiber groups than in the control (2.9 microns), for instance, 36.95 microns in potassium titanate fiber group, 15.90 microns crocidolite group, 13.00 microns basic magnesium sulfate fiber group, and 10.45 microns in the rockwool group. Although both pleural thickening and mesothelioma are known as peculiar lesions in asbestos-exposed people, it might also be suggested that these lesions could be induced by different mechanisms from the result that there was no relation between the pleural thickening and mesothelioma incidence in hamsters.
A reanalysis of the Stanton et al. pleural sarcoma data. G.W. Oehlert. 1991;54(2):194-205. PubMed · Publisher

Abstract

An analysis of the Stanton et al. (1981, J. Natl. Cancer Inst. 67, 965-975) data reconfirms number of index particles as the primary dimensional predictor of tumor incidence. Fitting separate intercepts and/or slopes to each mineral type results in substantial significant improvement in fit, indicating the importance of mineral type. This contrasts with the "Stanton hypothesis," which states that dimensional properties alone determine carcinogenesis. Log mean aspect ratio is not as good a predictor of tumor incidence as the number of index particles; among those samples that did not have index particles, log mean aspect ratio is not a significant predictor of tumor incidence.
Assessments of lung digestion methods for recovery of fibers. D.B. Warheit, H.C. Hwang, L. Achinko. 1991;54(2):183-93. PubMed · Publisher

Abstract

Evaluation of the pulmonary hazards associated with exposure to fibrous materials tends to be more complicated than assessments required for particulate materials. Fibers are defined by aspect ratios and it is generally considered that physical dimensions play an important role in the pathogenesis of fiber-related lung diseases. Several digestion techniques have been used to recover fibers from exposed lung tissue for clearance studies. Because many of the digestion fluids are corrosive (e.g., bleach, KOH), it is conceivable that the dimensions of recovered fibers are modified during the tissue digestion methods to assess whether the physical dimensions of bulk samples of fibers were altered following simulated digestion processing. Aliquots of crocidolite and chrysotile asbestos, Kevlar aramid, wollastonite, polyacrylonitrile (pan)-based carbon, and glass fibers were incubated with either saline, bleach, or KOH and then filtered. Scanning electron microscopy techniques were utilized to measure the physical dimensions (i.e., lengths and diameters) of at least 160 fibers per treatment group of each fiber type. Our results showed that the lengths and diameters of glass fibers and wollastonite were altered after treatment with KOH. In addition, treatment with bleach produced a small reduction in both asbestos fiber-type diameters, and greater changes in Kevlar and wollastonite diameters and carbon fiber lengths (P less than 0.05). These results indicate that lung digestion methods should be carefully assessed for each fiber type before initiating fiber clearance studies.
Dehydroepiandrosterone inhibits the spontaneous release of superoxide radical by alveolar macrophages in vitro in asbestosis. W.N. Rom, T. Harkin. 1991;55(2):145-56. PubMed · Publisher

Abstract

Asbestosis is characterized by an alveolar macrophage alveolitis with injury and fibrosis of the lower respiratory tract. Alveolar macrophages recovered by bronchoalveolar lavage spontaneously release exaggerated amounts of oxidants including superoxide anion and hydrogen peroxide that may mediate alveolar epithelial cell injury. Dehydroepiandrosterone (DHEA) is a normally occurring adrenal androgen that inhibits glucose-6-phosphate dehydrogenase, the initial enzyme in the pentose phosphate shunt necessary for NADPH generation and superoxide anion formation. In this regard, we hypothesized that DHEA may reduce asbestos-induced oxidant release. DHEA added in vitro to alveolar macrophages lavaged from 11 nonsmoking asbestos workers significantly reduced superoxide anion release. DHEA was measured in bronchoalveolar lavage and found to be similar to serum concentrations. DHEA is an antioxidant and potential anticarcinogenic agent that may have a therapeutic role in reducing the increased oxidant burden in asbestos-induced alveolitis of the lower respiratory tract.
Increased production of plasminogen activator inhibitor in vitro by pleural leukocytes from rats intratracheally instilled with crocidolite asbestos. X.Y. Li, G.M. Brown, D. Lamb, et al. 1991;55(2):135-44. PubMed · Publisher

Abstract

We have previously reported that normal pleural leukocytes secrete a urokinase-type plasminogen activator inhibitor (PAI) in culture. In view of the pathogenic effects of asbestos on the pleura, in particular pleural fibrosis, we have extended these observations to crocidolite asbestos-exposed rats. Pleural leukocytes from rats exposed to crocidolite asbestos were found to secrete more PAI in culture than controls. The activity of PAI in pleural leukocyte-conditioned medium increased in a dose-dependent manner in relation to the quantity of asbestos injected into the lung. However, with increasing time post asbestos instillation, there was no significant change in the secretion of PAI by pleural leukocytes in culture compared with earlier time points of crocidolite-exposed rats. Plasminogen activator was not detectable in the conditioned medium at any time point. The data derived from this study may help to elucidate the pathogenesis of some pleural disorders caused by exposure to fibrous dusts in the lungs.
Lung cell toxicity experimentally induced by a mixed dust from Mexicali, Baja California, Mexico. A.R. Osornio-Vargas, N.A. Hernández-Rodríguez, A.G. Yáñez-Buruel, et al. 1991;56(1):31-47. PubMed · Publisher

Abstract

Lung disease caused by nonoccupational exposures to inorganic particles from the soil has been reported in several areas of the world. We tested the toxic potential of dust samples from a Mexican city (Mexicali) that is frequently affected by dust storms and is geographically related to the area of San Diego, CA, where constituents of the soil have been reported to be fibrogenic. We found that samples of Mexicali dust are a mixture of approximately 75% potassium aluminum silicates (illite) and approximately 20% silica. Respirable size particles were highly hemolytic and induced lactic dehydrogenase release from alveolar macrophages exposed in vitro. Animals instilled intratracheally with the dust developed a multifocal interstitial lung disease associated with deposits of the aluminum silicates, which were identified by X-ray microanalysis. Inhalation studies in rats demonstrated that the majority of particles were deposited preferentially at the first alveolar duct bifurcations. Twenty-four hours later, numerous particles had been ingested by alveolar macrophages that had migrated to those sites of deposition. It is proposed that alveolar macrophages are attracted to the deposited particles by complement fragments since Mexicali dust is capable of activating complement proteins from both serum and bronchoalveolar lavage. Activation resulted in alveolar macrophage chemotaxis. Mexicali dust induced biological activities and lung changes similar to those of asbestos and silica, suggesting that this material could be an etiologic agent of pulmonary fibrosis in exposed individuals.
Polyvinylpyridine-N-oxide and carboxymethyl cellulose inhibit mineral dust-induced production of reactive oxygen species by human macrophages. P. Nyberg. 1991;55(2):157-64. PubMed · Publisher

Abstract

Polyvinylpyridine-N-oxide (PVPNO) and carboxymethyl cellulose (CMC) are known to inhibit the cytotoxic effects of quartz particles and chrysotile asbestos fibers, respectively. The effect of PVPNO and CMC on mineral dust-induced production of reactive oxygen species (ROS) by human monocyte-derived macrophages was studied using lucigenin-dependent chemiluminescence. Ten micrograms of PVPNO inhibited the ROS production induced by 100 micrograms of quartz completely, but caused only 25% inhibition of the response to 100 micrograms of chrysotile. Ten micrograms of CMC inhibited the chrysotile-induced ROS production to 70%, but had a weak effect on the responses to quartz. Neither PVPNO nor CMC caused any inhibition of the ROS responses to serum-opsonized zymosan. PVPNO was bound to both quartz and chrysotile, but no binding of CMC to either dust could be detected. Neither PVPNO nor CMC had any superoxide scavenging effect. In conclusion, PVPNO and CMC seem to selectively modify mineral dust surface properties, which are of importance in the induction of ROS production by phagocytes. These observations may be useful in describing the pathogenesis of mineral dust-induced diseases, and may also have therapeutic implications.
Regulation of in-place asbestos-containing material. N. Cohen. 1991;55(1):97-106. Review PubMed · Publisher

Abstract

Approximately two-thirds of New York City's 800,000 buildings contain asbestos. Most of this material is damaged or deteriorating. Legislation pending in the New York City Council (Bill number 453) would require virtually all building owners to inspect for asbestos, to develop management and maintenance plans to prevent disturbance of intact material, and to provide notice of the presence of asbestos to building occupants. This paper reviews the legislation and discusses its features that have been questioned. It concludes that regulation of in-place asbestos is necessary and appropriate.
The immediate effects of silicon carbide whiskers upon ciliated tracheal epithelium. G.L. Vaughan, J.R. Kennedy, S.A. Trently. 1991;56(2):178-85. PubMed · Publisher

Abstract

Considering the relationship between toxicity of dust and particle geometry, as exhibited by asbestos, we have examined short-term biological effects of SiC whiskers (SiCW) in vitro and in vivo. Cultured explants of tracheal epithelium were exposed to a range of SiCW concentrations. There were no dramatic effects on ciliary function as measured by an optical spectrum analysis system that provided discrete ciliary frequencies. Particles were swept by ciliary activity into nonciliated regions where foci of extensive cell damage and death were observed with whiskers penetrating epithelial layers into the underlying tissues. Similar necrotic foci were observed in tracheae from rats exposed by intratracheal instillation to SiC whiskers in vivo.
The toxicity, in vitro, of silicon carbide whiskers. G.L. Vaughan, J. Jordan, S. Karr. 1991;56(1):57-67. PubMed · Publisher

Abstract

To mouse cells in culture, SiC whiskers (SiCW) and asbestos are similarly cytotoxic, disrupting cell membranes and killing cells. Both shorten cell generation time, increase the rate of DNA synthesis, increase total cell DNA content, and cause a loss in growth control often associated with malignant cellular transformation. Within the narrow size range of materials examined, the amount of damage appeared to be more a function of the number of whiskers present than of their size. Silicon carbide whiskers, if mishandled, may pose a serious health hazard to humans.
Airborne asbestos in public buildings. J. Chesson, J. Hatfield, B. Schultz, et al. 1990;51(1):100-7. PubMed · Publisher

Abstract

The U.S. Environmental Protection Agency sampled air in 49 government-owned buildings (six buildings with no asbestos-containing material, six buildings with asbestos-containing material in generally good condition, and 37 buildings with damaged asbestos-containing material). This is the most comprehensive study to date of airborne asbestos levels in U.S. public buildings during normal building activities. The air outside each building was also sampled. Air samples were analyzed by transmission electron microscopy using a direct transfer preparation technique. The results show an increasing trend in average airborne asbestos levels; outdoor levels are lowest and levels in buildings with damaged asbestos-containing material are highest. However, the measured levels and the differences between indoors and outdoors and between building categories are small in absolute magnitude. Comparable studies from Canada and the UK, although differing in their estimated concentrations, also conclude that while airborne asbestos levels may be elevated in buildings that contain asbestos, levels are generally low. This conclusion does not eliminate the possibility of higher airborne asbestos levels during maintenance or renovation that disturbs the asbestos-containing material.
Changes in lipid ordering of model phospholipid membranes treated with chrysotile and crocidolite asbestos. E.G. Gendek, A.R. Brody. 1990;53(2):152-67. PubMed · Publisher

Abstract

A variety of inorganic particles bind to cell membranes and cause alterations in phagocytosis, migration, and metabolism leading to eventual cell death. The mechanism which mediate these events at the complex membrane level are not known. In attempting to define the mechanisms of asbestos-induced membrane changes, we have prepared small unilamellar vesicles (SUV) of dipalmitoyl phosphatidylcholine as a simplified model of the cell membrane. Negatively stained preparations for electron microscopy demonstrated that the SUVs bind to both chrysotile and crocidolite asbestos fibers. Electron spin resonance showed that both asbestos types caused increased membrane rigidity at the level of the 12th carbon, whereas chrysotile induced increased rigidity at the 5th carbon level as well. Studies using DPPC membranes compared to SUVs made of phosphatidylcholine from egg yolk support the view that lipid peroxidation may play no significant role in alterations of membrane rigidity induced by the asbestos particle binding. Similar alterations of membrane rigidity and lipid peroxidation at the depth of the 12th carbon have been reported in complex naturally occurring erythrocyte membranes. This suggests that our observations may be relevant to biological membranes and that the model system of SUVs is appropriate for additional studies on the mechanisms of particle-induced membrane injury.
Coinhibition of viral interferon induction by benzo[a]pyrene in association with occupation-related particles. N. Hahon, J.A. Booth, L. Flowers. 1990;52(1):83-98. PubMed · Publisher

Abstract

Benzo[a]pyrene (B[a]P) in combination with coal, asbestos, or metal particles was studied for its inhibitory effects on interferon-alpha/beta induction by influenza virus in rhesus monkey kidney (LLC-MK2) cell monolayers. B[a]P per se had no adverse effect on the induction process. However, when cell cultures were pretreated with B[a]P that was bioactivated by rat liver S9 homogenate, from 52 to 65% inhibition of interferon induction occurred. Significantly greater (P less than 0.05) depression (coinhibition) of viral interferon induction (greater than 83%) resulted when bioactivated B[a]P was incorporated with coal particles representative of coal rank (anthracite, bituminous, lignite, peat). Coinhibition affected by bioactivated B[a]P was coal rank-independent but any interferon inhibitory activity affected by coal particles per se was coal rank-dependent. When metals (aluminum, aluminum oxide, ferric oxide, nickel, or chromium) or asbestos fibers (chrysotile, crocidolite, anthophyllite, or amosite) were individually mixed with bioactivated B[a]P, coinhibition of cellular interferon synthesis also resulted which was significantly greater (P less than 0.05) than that manifested by bioactivated B[a]P or particles per se. Coinhibition of interferon induction by silicates (Min-U-Sil, DQ-12, hypersthene, or wollastonite) and the bioactivated hydrocarbon was not in evidence although some silicates alone partially inhibited the induction process. Viral interferon induction was inhibited in a dose-response manner by B[a]P (+/- S9) in combination with selected particles. The adsorption of B[a]P to all types of particles was no more than 5.98 micrograms B[a]P/mg of particles and, moreover, less than 0.5% by weight. These findings provide further evidence that bioactivated B[a]P and occupation-related particles act together to coinhibit a biological defense mechanism, the interferon induction phase of the interferon system.
Fiber exposure reassessed with the new indices. T. Schneider, J. Skotte. 1990;51(1):108-16. PubMed · Publisher

Abstract

The concentration of airborne fibers longer than 5 microns, thinner than 3 microns, and with an aspect ratio exceeding 3 as counted by phase contrast optical microscopy is the most widely used fiber exposure index. Recently, more adequate, specific exposure indices for asbestosis, lung cancer, and mesothelioma risk have been suggested by Lippmann (1988, Environ. Res., 46, 86-106). The consequences of using these indices are examined on the basis of calculations for a broad range of theoretical and published size distributions. Optical microscopy appears to be a good predictor of the exposure indices for asbestosis and for lung cancer after scaling. Only fibers longer than about 3 microns need to be counted in a transmission electron microscope. The lung cancer index still cannot explain the large differences of risk among chrysotile exposures. Both the mesothelioma exposure index and the ratio mesothelioma to lung cancer index ranks in order of increasing risk: wollastonite, glass and mineral wool, amosite, glass microfibers, chrysotile, and crocidolite. Amosite is thus not ranked according to epidemiological evidence. Detailed size information should be made available so that the size criteria can be adjusted. It may still prove necessary to use fiber type specific concentration limits.
On the mechanism of cell internalization of chrysotile fibers: an immunocytochemical and ultrastructural study. W. Malorni, F. Iosi, M. Falchi, et al. 1990;52(2):164-77. PubMed · Publisher

Abstract

Human breast carcinoma cells (CG5) and human laryngeal carcinoma cells (HEp-2) were exposed to 10 and 50 micrograms/ml of small (about 5 microns) chrysotile asbestos fibers. Morphological and ultrastructural changes were evaluated by means of immunocytochemistry and by scanning and transmission electron microscopy. Our attention was focused on the mechanisms of cell internalization and on transport of chrysotile fibers. The fibers appeared to penetrate the cell cytoplasm and to be translocated in proximity of the nucleus. Small chrysotile fibers could also be found inside the nucleus of interphase cells. Involvement of the main cytoskeletal components, i.e., microfilaments, intermediate filaments, and microtubules, in the cytotoxicity of chrysotile fibers was also evaluated. Our findings suggest that after fiber penetration, a rearrangement of the cytoskeletal apparatus occurs. It has also been observed that small fibers remain associated with the cytoskeletal framework, which can thus play a role in asbestos intracytoplasmic translocation in epithelial cells. Furthermore, after the cell has completely recovered its morphology, fiber internalization ultimately seems to lead to the formation of giant multinucleated cells. These data could be indicative of an interaction occurring between asbestos fibers and the normal mitotic process. The disturbance of the cell cytoskeleton and the close morphologic contact between asbestos fibers and the cell's nuclear region may be of importance in explaining the well-known carcinogenic effects of asbestos mineral fibers.

1980s

Accumulation of mixed mineral dusts in the lungs of rats during chronic inhalation exposure. C.H. McMillan, A.D. Jones, J.H. Vincent, et al. 1989;48(2):218-37. PubMed · Publisher

Abstract

The effects of mixed dust exposure on pulmonary clearance during chronic exposure has been investigated using rats exposed to combinations of toxic and relatively nontoxic dusts: quartz (at respirable dust concentrations of 1 and 10 mg/m3) plus titanium dioxide (at 30 and 20 mg/m3, respectively), and amosite asbestos (2.5 mg/m3) plus titanium dioxide (15 mg/m3). The rats were exposed for 5 days per week, and for up to 16 weeks (for quartz) or up to 32 weeks (for asbestos). The lung burdens were compared with previously published results for exposure to single dusts under the same exposure regimens. The main feature of all these comparisons was the absence of significant differences between the lung burdens (at 3, 10, and 38 days postexposure) for single-dust and mixed-dust exposures. There was, however, some reduction in the postexposure clearance (as shown by the lung burdens at 94, 150, and 260 days postexposure) of titanium dioxide which appeared to be due to the presence of quartz in the lung. For the quartz plus titanium dioxide experiments, the lymph nodes were dissected and analyzed separately. These results showed that transfer to lymph nodes accounted for most of the postexposure clearance for titanium dioxide, and almost all for the quartz.
Bronchoalveolar lavage analysis, gallium-67 lung scanning and soluble interleukin-2 receptor levels in asbestos exposure. G.L. Delclos, D.G. Flitcraft, K.P. Brousseau, et al. 1989;48(2):164-78. PubMed · Publisher

Abstract

This study examined different markers of lung immunologic and inflammatory responses to previous asbestos exposure. We performed bronchoalveolar lavage (BAL) and gallium-67 (67Ga) lung scans and measured serum and BAL soluble interleukin-2 receptor (IL-2R) and angiotensin-converting enzyme (SACE) levels in 32 subjects with a history of significant asbestos exposure, 14 without (EXP) and 18 with (ASB) radiographic evidence of asbestosis. BAL analysis revealed increases in neutrophils in both ASB and EXP when compared to controls (P less than 0.01), which persisted after adjustment for smoking category. Although significant abnormalities of macrophage and total lymphocyte profiles were not found in the study population, lymphocyte subpopulation analysis revealed elevation of BAL T4/T8 ratios in the entire study group (ASB + EXP) when compared to controls (P less than 0.05), independent of smoking category. 67Ga lung scan activity was increased in 56% of ASB and in 36% of EXP: no correlations between positive scans and different radiological and functional parameters could be found. There was no significant elevation of mean SACE, serum, or BAL IL-2R levels in any of the study categories. These data suggest that asbestos exposure may be associated with parenchymal inflammation, even in the absence of clinical criteria for asbestosis. Abnormalities of gallium uptake and of BAL analysis reflect the clinically inapparent inflammation. The increased BAL T4/T8 ratios observed suggest that abnormal local pulmonary immunoregulation may play a role in the pathogenesis of asbestos-related lung diseases.
Evaluation of the pleural malignant mesothelioma patients with the relation of asbestos exposure. T. Kishimoto, K. Okada, T. Sato, et al. 1989;48(1):42-8. PubMed · Publisher

Abstract

There has been a recent increase in the number of patients with malignant mesothelioma in parts of Japan where Naval shipyards were located during World War II. This can be attributed to asbestos exposure during work in the shipyard. We have studied eight patients who were seen between 1984 and 1986 in Kure Kyosai Hospital. All had a history of asbestos exposure, seven in a Naval shipyard. In these seven cases, the latent period between exposure and the appearance of mesothelioma was 43-49 years. Quantification of asbestos bodies in the lung indicated a high concentration in all patients, giving further weight to the concept that asbestos is an etiologic factor in the genesis of mesothelioma. The major types of asbestos fibers were crocidolite and amosite. The study of structural features of these two types may provide a clue to the pathogenesis of the disease.
Lung asbestos burden in shipyard and construction workers with mesothelioma: comparison with burdens in subjects with asbestosis or lung cancer. M.L. Warnock. 1989;50(1):68-85. PubMed · Publisher

Abstract

Although mesothelioma is generally considered to be caused by asbestos, epidemiologic studies indicate that some cases have another cause. In order to determine whether pulmonary asbestos burden can be used to define asbestos-related mesotheliomas, asbestos burden was quantified in 27 shipyard or construction workers with diffuse malignant mesothelioma of the pleura or peritoneum and a history of asbestos exposure. Their burden was significantly greater than the burden found in 19 unexposed men (P less than 0.001). The burdens were also compared to those of previously reported subjects with asbestosis or lung cancer. The median concentration for total amphibole fibers (2.7 million/g dry lung) in subjects with mesothelioma did not differ significantly from our previously reported median values for 14 subjects with asbestosis (1.3 million/g dry lung) or for 60 asbestos workers with lung cancer (1.3 million/g dry lung). Fiber size distribution for amosite, the most prevalent fiber type, was similar in all three subject groups. Fifteen of 25 (60%) subjects with mesothelioma had mild asbestosis. Asbestos body (AB) concentrations were greater than or equal to 1900/g dry lung, and total amphibole fiber concentrations were greater than or equal to 390,000/g dry lung. Counts of ABs greater than or equal to 0.5/cm2 in histologic sections always signified both of these concentrations in extracts. Thus, histologic sections showing greater than or equal to 0.5 ABs/cm2 or extracts containing asbestos body or amphibole fiber concentrations of at least 1900 or 390,000/g dry lung, respectively, will confirm an asbestos-related mesothelioma.
Monocyte-derived growth factors in asbestos-induced interstitial fibrosis. D.A. Schwartz, L. Rosenstock, J.G. Clark. 1989;49(2):283-94. PubMed · Publisher

Abstract

Asbestos-induced pulmonary fibrosis is thought to result from a series of cellular interactions involving the alveolar macrophage and the lung fibroblast. Although a dose-response relation has been established between asbestos exposure and the development of interstitial fibrosis, the majority of workers exposed even to high concentrations of asbestos do not develop radiographically evident interstitial fibrosis. As a means of understanding the pathogenesis of asbestos-induced fibrosis and the differential host response to the asbestos fiber, we studied the production of monocyte-derived growth factors in subjects with asbestosis (N = 5) and normal exposure-matched controls (N = 5). Under unstimulated culture conditions, the conditioned medium (CM) from monocytes from control subjects had a greater proliferative effect on fibroblasts than monocyte CM from patients with asbestosis. With CM from concanavalin A-stimulated monocytes, the proliferative response of the fibroblast was similar in those with asbestosis and control subjects. Freshly isolated monocytes from both normal subjects and patients with asbestosis did not express the gene for the B chain of platelet-derived growth factor (PDGF) as evaluated by hybridization with a PDGF-specific human cDNA probe. After 20 hr of culture in concanavalin A, monocytes from normal subjects expressed the gene for the B chain of PDGF while, under the same culture conditions, none of the monocyte preparations from patients with asbestosis produced mRNA for this growth factor. These data indicate that peripheral blood monocytes from patients with asbestosis compared to exposure-matched controls have a reduced capacity to produce growth factor activity as measured by mitogenic activity and mRNA levels for the B chain of PDGF. These results suggest that peripheral blood monocytes from patients with asbestosis may comprise a less mature population of cells compared to exposure-matched controls.
On the release of asbestos fibers from weathered and corroded asbestos cement products. K.R. Spurny. 1989;48(1):100-16. PubMed · Publisher

Abstract

The controversy on whether weathered and corroded asbestos cement products are emitting biologically significant asbestos fiber concentrations in ambient air has not been resolved. Nor is it known if the weathered and corroded asbestos cement products release asbestos fibers which have the same carcinogenic potency as "standard" chrysotile. The purpose of this research project was to develop a method for sampling and measuring asbestos fiber emissions from solid planar surfaces (i.e., roofs and facades) consisting of asbestos cement products and to develop methods for studying the physical and chemical changes and the carcinogenic potency of the emitted fibers. Using this method asbestos fiber emissions in ambient air have been measured in the FRG during 1984/1986. The emissions of asbestos fibers longer than 5 microns were in the range 10(6) to 10(8) fibers/m2.hr. The ambient air concentrations of these asbestos fibers were for the most part less than 10(3) fibers/m3. It was shown that the emitted asbestos fibers were chemically changed and it was shown with animal experiments that their carcinogenic potency did not differ from the carcinogenicity of "standard" chrysotile fibers.
Plasma lipid peroxides among workers exposed to silica or asbestos dusts. A.A. Kamal, A. Gomaa, M. el Khafif, et al. 1989;49(2):173-80. PubMed · Publisher

Abstract

Plasma malondialdehyde (MDA) (an indicator of lipid peroxidation) was determined in random samples of workers (age range 25-60 years) exposed to silica dust (n = 31, mean exposure duration 21.3 +/- 8.3 years) or asbestos dust (n = 59, mean exposure duration 15.6 +/- 4.5 years) and in 52 age-matched healthy male controls. MDA levels of both exposed groups were significantly higher than that of the controls and were significantly higher among workers exposed to asbestos than among those exposed to silica dusts. Neither age nor smoking was related to MDA levels among both controls and exposed workers; among the latter group MDA was not significantly correlated with duration of exposure. Mean MDA levels of exposed workers with radiographic signs of lung fibrosis or pleural thickening and of those without such signs were not significantly different, except in the case of asbestos-exposed workers where it was significantly less than that of those without such signs. Differences between mean durations of dust exposure of workers with radiographic signs of lung fibrosis and those without such signs were statistically insignificant. The results suggest the possible involvement of lipid peroxidation on exposure to silica or asbestos dusts in humans and possible development of antioxidant mechanism(s) on prolonged dust exposure and support the opinion that development of pneumoconiosis depends on susceptibility factor(s).
Rat lung reactivity to natural and man-made fibrous silicates following short-term exposure. I. Lemaire, P.G. Dionne, D. Nadeau, et al. 1989;48(2):193-210. PubMed · Publisher

Abstract

The inflammatory and fibrogenic potential of three naturally occurring and two man-made industrial minerals were compared. Groups of five rats each received respectively a single intratracheal instillation of saline (control), UICC chrysotile B asbestos, short chrysotile 4T30, attapulgite, xonotlite (a calcium silicate), and Fiberfrax (an aluminum silicate) at doses of 1, 5, and 10 mg. One month after the treatment, assessment of lung morphology and bronchoalveolar lavage were performed on each animal. Under these conditions, UICC chrysotile B at all doses tested (1, 5, and 10 mg) induced fibrotic lesions in bronchiolar tissues while short chrysotile 4T30 (1, 5, and 10 mg) caused focal accumulation of inflammatory cells in the alveolar structures but no apparent fibrosis. Compared to these positive reactions with different fibrogenicity, xonotlite caused minimal inflammatory reactions detectable only at high dose (10 mg) and by bronchoalveolar analysis. By contrast, the rat lung reacted more significantly to attapulgite and Fiberfrax although the tissue reaction differed considerably for these two materials. While attapulgite, at doses up to 10 mg caused minimal reactions characterized by mononuclear cell infiltration mainly in the alveolar structures, Fiberfrax at 1 mg and higher caused significant granulomatous reactions and the appearance of early fibrosis. Overall the order of lung biological reactivity observed for the various silicates was xonotlite much less than attapulgite less than short chrysotile 4T30 less than Fiberfrax less than UICC chrysotile B. These observations indicate that Fiberfrax, attapulgite, and, to a lesser extent, xonotlite are biologically active within the time span studied and potentially deleterious for lung tissue.
Talc deposition and effects after 20 days of repeated inhalation exposure of rats and mice to talc. J.A. Pickrell, M.B. Snipes, J.M. Benson, et al. 1989;49(2):233-45. PubMed · Publisher

Abstract

The relationship between the inhalation exposure concentration of talc and the resulting lung burdens and histologic lesions was studied using groups of 20 F344/Crl rats and 20 B6C3F mice (10 male and 10 female) exposed to one of three concentrations of asbestos-free talc for 6 hr/day, 5 days/week for 4 weeks. Controls were exposed to filtered air using the same schedule. The pulmonary retention of talc and the development of pulmonary pathology were evaluated. The mass median aerodynamic diameter (MMAD) of the talc aerosol was 3.0 microns with a geometric standard deviation (sigma g) of 1.9. The mean exposure concentrations for rats were 0, 2.3, 4.3, and 17 mg talc/m3. Lung burdens in rats averaged 0, 0.07, 0.17, and 0.72 mg talc/g lung after the 20-day inhalation exposure; thus, the amount retained in the lung per unit of exposure concentration increased with increasing concentration. Mean exposure concentrations for the mice were 0, 2.2, 5.7, and 20.4 mg of talc/m3, which resulted in lung burdens of 0, 0.10, 0.29, and 1.0 mg talc/g lung; thus, the relationship between exposure concentration and the amount retained in the lung was approximately constant. Lung burdens from this study were used to project lung burdens that would result from longer exposures of rodents and man. No clinical signs were observed in the rats or mice prior to sacrifice 24 hr after the last exposure day. Histologic alterations in lung tissue consisted of only a modest, diffuse increase of talc-containing, free macrophages within alveolar spaces in both rat and mouse groups exposed to the highest level of talc for 20 days. A model simulating chronic talc inhalation exposure of rats and mice predicted lung burdens of 2-3 mg talc/g lung (wet wt) if animals were exposed to 17 mg talc/m3 for 2 years, and deposition and clearance of talc were unchanged by continued exposure. A potential limitation in this modeling is that if clearance of talc is delayed by continued exposure, the accumulated talc lung burdens would be higher than those projected by the simulation model. Humans exposed to aerosols of respirable talc are projected to accumulate much higher lung burdens than would occur in rodents exposed to the same aerosol, because humans have a higher estimated deposition fraction and slower estimated clearance of the deposited talc dust. Equilibrium lung burdens of greater than or equal to 2 mg talc/g lung were predicted for human exposures at or near the TLV for talc.
Asbestos exposure indices. M. Lippmann. 1988;46(1):86-106. Review PubMed · Publisher

Abstract

The ability of inhaled asbestos to produce asbestosis, lung cancer, and mesothelioma in both humans and animals is well established, and asbestos exposures in the occupational and general community environment are recognized as significant hazards. However, it has not been possible to establish realistic and credible dose-response relationships, primarily because of our inability to define which constituents of the aerosols produce or initiate the pathological responses. It is generally acknowledged that the responses are associated with the fibers rather than the nonfibrous silicate mineral of the same chemical composition. Available data from experimental studies in animals exposed by injection and inhalation to fibers of defined size distributions are reviewed, alone with data from studies of fiber distributions in lungs of exposed humans in relation to the effects associated with the retained fibers. It is concluded that asbestosis is most closely related to the surface area of retained fibers, that mesothelioma is most closely associated with numbers of fibers longer than approximately 5 microns and thinner than approximately 0.1 micron, and that lung cancer is most closely associated with fibers longer than approximately 10 microns and thicker than approximately 0.15 micron. The implications of these conclusions on methods for fiber sampling and analyses are discussed.
Asbestos-contaminated drinking water: its impact on household air. J.S. Webber, S. Syrotynski, M.V. King. 1988;46(2):153-67. PubMed · Publisher

Abstract

Asbestos contamination in excess of 10 billion fibers per liter was detected in a community's drinking water. To assess the possibility of waterborne asbestos becoming airborne, air samples were collected from impacted houses receiving contaminated water from three control houses. Collected within each house were three samples on 0.6-micrometer-pore Nuclepore filters and three samples on 0.8-micrometer-pore Millipore filters. In addition, bulk samples of suspect material and water samples were collected. Mean waterborne asbestos concentrations were 24 million fibers per liter (MFL) in the impacted houses versus only 1.1 MFL in the control houses. Transmission electron microscopy revealed that airborne asbestos concentrations were highest in impacted houses, with airborne asbestos concentrations positively correlated with waterborne concentrations. For fiber and mass measurements on both filter types, airborne asbestos concentrations were significantly higher in the impacted houses: mean concentrations in impacted houses were 0.12 fibers/cm3 and 1.7 ng/m3 on Nuclepore filters and 0.053 fibers/cm3 and 2.3 ng/m3 on Millipore filters versus only 0.037 fibers/cm3 and 0.31 ng/m3 on Nuclepore filters and 0.0077 fibers/cm3 and 0.14 ng/m3 on Millipore filters from control houses. Also detected in the air samples from impacted houses were clusters of chrysotile, often with several hundreds of fibers. When estimates of these individual fibers were added to the total fiber count, the difference between the impacted and control houses became even greater. The increased concentrations in impacted houses were due primarily to short (less than 1 micrometer) fibers. Bulk samples did not reveal likely materials within the impacted houses to account for these differences. Thus high levels of waterborne asbestos were apparently the source of increased concentrations of airborne asbestos within these houses.
Significance of mass and number of fibers in the correlation of V79 cytotoxicity with tumorigenic potential of mineral fibers. L.D. Palekar, B.M. Most, D.L. Coffin. 1988;46(2):142-52. PubMed · Publisher

Abstract

The cytotoxicity of four tumorigenic minerals: erionite(w), erionite(c), UICC crocidolite, UICC chrysotile and nontumorigenic mordenite was compared in Chinese hamster lung V79 cells. The results indicate that the tumorigenic minerals were toxic by showing more than 50% toxicity for at least one dose between 10 and 100 micrograms/ml. Mordenite was nontoxic. Higher potency of erionite, however, was not evident in this system when the dose considered was expressed in mass units. On the other hand, when the degree of cytotoxicity was considered per number of mineral fibers, it was clear that fewer erionite fibers of all three dimensions (A greater than or equal to 3; L greater than or equal to 8.0 micrometers, W less than or equal to 0.25 micrometer; and L less than 5.0 micrometers, W less than or equal to 0.1 micrometer) than those of UICC crocidolite and UICC chrysotile were needed to produce similar toxicity. This suggests that the dose in number of fibers may be a better parameter than the total mass dose as a correlate of tumorigenic potential.
A model for predicting crocidolite fiber size distributions. R.L. Virta, J.M. Segreti. 1987;44(1):148-60. PubMed · Publisher

Abstract

To minimize the problems of sample mass inconsistency associated with limited fiber counts, a model has been developed to predict the particle size distribution for crocidolite asbestos fibers with lengths exceeding the median log length value. With this model, it is possible to predict the dimensions of many more fibers than it is practical to measure by typical electron microscopic techniques. Thus, sample mass extrapolations, required for animal implantation studies, can be based on a much larger number of particles, reducing error that could occur, for example, from the presence of one or two very large particles. The model assumes a linear relationship between length and width. The number of fibers predicted in each length category is determined from the measured data. Particle lengths were randomly chosen within size classes, and the corresponding widths were predicted using the model. The similarity of the predicted population to the actual population was tested by comparing the width distributions using the chi-square test at the 90% confidence level. Model populations ranging from 250 to 10,000 particles were predicted. Those populations with 2500 or more fibers were similar to the actual sample in their size characteristics. Predicted populations in excess of 7500 fibers were required to produce consistent sample masses.
A predictive model for determining asbestos concentrations for fibers less than five micrometers in length. M.J. Kiefer, R.M. Buchan, T.J. Keefe, et al. 1987;43(1):31-8. PubMed · Publisher

Abstract

The controversy of whether small asbestos fibers are biologically significant has not been resolved. The present standard method for evaluating asbestos fiber concentrations in workroom air excludes fibers less than 5 micron long even though it has been shown that small fiber concentrations dominate in a dust cloud. This research project was conducted to develop a mathematical model whereby one could predict small (less than 5 micron length) asbestos fiber concentration based on the fiber count concentration determined by phase contrast microscope analysis. Dry chrysotile asbestos was aerosolized into a chamber and sampled by membrane filtration. Segments from each filter were analyzed by both the NIOSH technique using phase contrast microscopy (PCM) and scanning electron microscopy (SEM) at 2000 X for fiber concentrations. A linear relationship was found to exist between the natural logarithm of the SEM-determined concentration and the natural logarithm of the PCM-determined concentration (r = 0.852). Using these data, a mathematical model was developed to predict SEM concentrations based on PCM counts. This model may have application in retrospective epidemiological studies for estimating small fiber exposure levels to determine if small fibers play a role in disease production. The greatest utility would be in those retrospective studies where the only exposure information available is based on PCM counts.
Adsorption of proteins by chrysotile and crocidolite: role of molecular weight and charge density. F. Valerio, D. Balducci, A. Lazzarotto. 1987;44(2):312-20. PubMed · Publisher

Abstract

Transferrin, gamma-globulin, fibrinogen, aldolase, albumin, and cytochrome c at concentration of 0.45 muMole/liter were treated with chrysotile and crocidolite fibers. Specific adsorption for each protein and correlations between protein molecular weight and charge density in experimental conditions were evaluated. Chrysotile showed the highest absorption capability, particularly toward albumin and cytochrome c. Affinity for fibers was poorly linked to protein molecular weight; on the contrary, a good correlation with protein charge density was found. The sign of charge on fibers and proteins seemed to play a minor role in adsorption.
Asbestos and renal adenocarcinoma: a case-control study. M. Maclure. 1987;42(2):353-61. PubMed · Publisher

Abstract

A case-control study of renal adenocarcinoma has corroborated the hypothesis that asbestos is a cause of the disease. The odds of having been moderately or heavily exposed to asbestos 30 years before diagnosis were 45:473 among cases, whereas the comparable odds among controls were 26:492. A matched-pair analysis yielded an exposure odds ratio of 1.8 with 95% confidence limits of 1.1 and 3.1. After controlling for potential confounders and selection factors by means of logistic regression, the incidence rate ratio was estimated to be 1.6, with a one-sided 95% confidence limit of 1.0.
Asbestos bodies or fibers and the diagnosis of asbestosis. M.L. Warnock, G. Wolery. 1987;44(1):29-44. PubMed · Publisher

Abstract

A committee of the College of American Pathologists has proposed that the diagnosis of asbestosis requires fibrosis in respiratory bronchiolar walls and the presence of asbestos bodies (ABs) in tissue sections. To determine whether histologic ABs reliably reflect asbestos fiber concentrations in asbestosis, we compared the concentration of ABs in histologic sections to concentrations of ABs and fibers in tissue extracts of 14 asbestos workers with nonspecific interstitial fibrosis. ABs in histologic sections and extracts correlated well, r = 0.95. Counted and classified by electron microscopy, electron diffraction, and X-ray spectroscopy, commercial amphibole fibers (r = 0.94) also correlated well with ABs, but noncommercial amphiboles (r = -0.02) or chrysotile (r = 0.29) did not. In five subjects with a high percentage of noncommerical amphibole fibers, fewer than 0.5 histologic ABs/cm2 were present despite a total amphibole concentration that was similar to that in subjects with more histologic ABs. We conclude that ABs will be scarce or absent in histologic sections from some subjects with asbestosis, and that for such subjects, extracts of asbestos fibers should yield over 500,000 total amphibole fibers/g dry lung to signify that interstitial fibrosis may be caused by asbestos.
Characterization of mineral population by index particle: implication for the Stanton hypothesis. A.G. Wylie, R.L. Virta, J.M. Segreti. 1987;43(2):427-39. PubMed · Publisher

Abstract

Fibers from seven crocidolite samples used by M. F. Stanton et al. (J. Natl. Cancer Inst. 67, 965-975 (1981] were measured from STEM and optical images. Their masses were computed. From these data, the population was normalized to a sample mass of 1 micrograms, and the number of fibers in various size categories of a 1-microgram sample was compared to the tumor probability for each sample. The purposes of this study were (1) to evaluate errors in and the utility of population characterization by index number (log of the number of particles longer than 8 micron with widths equal to or less than 0.25 micron) and (2) to review the Stanton hypothesis in view of this analysis. The study found that in most cases the index number is a reliable population parameter. However, index numbers between 0 and 2.5 cannot be obtained. Therefore, populations of mineral fibers will fall into two groups: those without index particles, which have indeterminant index numbers, and those with index numbers between 2.5 and 6.0. Within Stanton's populations that contain index particles, where y equals logit tumor probability and x equals index number, r equals 0.307 (insignificant). Where y equals tumor probability and x equals index number, r equals 0.503 (significant). The correlation coefficients are low enough to suggest the possibility that factors other than size and shape play a role in mineral fiber carcinogenicity.
Clearance and dimensional changes of crocidolite asbestos fibers isolated from lungs of rats following short-term exposure. V.L. Roggli, M.H. George, A.R. Brody. 1987;42(1):94-105. PubMed · Publisher

Abstract

Previous studies in this laboratory have demonstrated fiber clearance and dimensional changes in chrysotile asbestos using a rat inhalational model of short-term exposure. The purpose of the present study was to determine whether or not similar changes occurred in crocidolite asbestos fibers isolated from the lungs of rats at various intervals after termination of exposure. Fibers were recovered on a membrane filter using a sodium hypochlorite digestion-concentration technique, and the numbers and dimensions of the fibers assessed using scanning electron microscopy. The mass of crocidolite asbestos retained in the lung was then calculated. Of the respirable fraction, 19% was deposited in the lungs, and 25% of this amount was still present 1 month after exposure. These values are similar to the 23% deposition and 19% retention rates for chrysotile determined in our previous study. There was a progressive increase in mean fiber length with time postexposure (P less than 0.05), but no significant changes in the diameter of the population of crocidolite fibers retained in the lung. Thus it appears that the tendency for longer fibers to be retained within lung tissue is a characteristic shared by serpentine and amphibole asbestos fibers, whereas longitudinal splitting with progressive decrease in mean fiber diameter in vivo occurs primarily with the serpentine fibers.
Comparative efficiency of Nuclepore filters of various pore sizes as used in digestion studies of tissue. M.F. O'Sullivan, C.J. Corn, R.F. Dodson. 1987;43(1):97-103. PubMed · Publisher

Abstract

Some of the widely used techniques employed in assessing asbestos load in lung tissue include the use of digestion techniques, in which particulates are entrapped on a filter surface. However, the actual filtering efficiency of various pore sizes as applicable to collecting fibrous material has not been tested. The present study evaluates such filtration efficiency by using a series of back-to-back filters of various sizes. It was confirmed that fibers pass through the pores and that with the larger pore sizes an appreciable loss of small fibers can occur. It is suggested that a filter with 0.2-micron pore size offered a reasonable compromise for both filtration efficiency as well as sufficiently rapid filtration rates for most studies.
Crocidolite-induced lipid peroxidation in rat lung microsomes. I. Role of different ions. M. Gulumian, T.A. Kilroe-Smith. 1987;43(1):267-73. PubMed · Publisher

Abstract

Lipid peroxidation is increased by ferrous or ferric ions in rat lung microsomes both from rats pretreated with 3-methylcholanthrene and from untreated controls. This increase was dependent on the concentration of these ions in the reaction mixture. Crocidolite alone increased peroxidation in microsomal fractions. However, addition of ferric or ferrous ions with the crocidolite did not give a greater increase in the amount of peroxidation in microsomes. Chelation with EDTA of iron, whether originally present as free ions in the solution or attached to crocidolite, prevented lipid peroxidation. NADPH alone, when added to the microsomal fractions, did not produce any significant effect. However, when added concomitantly with crocidolite fibers, NADPH reduced the effect of crocidolite on lipid peroxidation. Magnesium, manganese, and calcium ions did not produce any significant effect on lipid peroxidation in the presence or absence of crocidolite. A reduced pH enhanced the rate of lipid peroxidation in line with increased solubility of iron salts at these pH values. All the above observations, taken together, lead to the conclusion that it is the iron in the crocidolite that is responsible for the latter's ability to enhance lipid peroxidation.
Crocidolite-induced lipid peroxidation. II. Role of antioxidants. M. Gulumian, T.A. Kilroe-Smith. 1987;44(2):254-9. PubMed · Publisher

Abstract

Asbestos fibers in vitro produce lipid peroxidation in rat lung microsomes. Butylated hydroxytoluene prevented this peroxidation. Ascorbate in low concentrations enhanced peroxidation of lipids but inhibited it at concentrations above 4 mmole/liter so that it partially protected membrane lipids from peroxidation produced by asbestos fibers. Reduced glutathione added to microsomes gave increased peroxidation at increased concentrations up to 20 mmol/liter. At 40 mmol/liter peroxidation was prevented. Glutathione had no obvious effect on the level of peroxidation produced by asbestos fibers. The 105,000g supernatant cell fraction added either with or without glutathione gave a decrease in the amount of lipid peroxidation produced by asbestos fibers. The protective action of these reducing agents suggests a possible use as prophylactic agents against the harmful effects of inhaled asbestos.
Effects of in vitro asbestos exposure on natural killer and antibody-dependent cellular cytotoxicity. R.G. Barbers, J. Oishi. 1987;43(1):217-26. PubMed · Publisher

Abstract

Human peripheral blood lymphocytes (PBL) were exposed in vitro to asbestos fibers. Antibody-dependent cellular cytotoxicity (ADCC) activity and natural killer (NK) activity were examined by a chromium-51 release assay. There was a statistically significant enhancement of ADCC and NK activity by chrysotile and crocidolite fibers when cultured together with PBL for a period of 42 hr in medium containing a concentration of at least 2.5% fetal calf serum (P less than 0.05). Isolation of large granular lymphocytes to measure NK activity, however, showed the opposite effect when exposed to asbestos fibers (P less than 0.05). Our results indicate that asbestos fibers can directly affect lymphoid cytotoxic responses in vitro and may provide clues to immunopathogenic mechanisms for the occurrence of neoplasms in vivo.
Mineral particles in the lungs of subjects resident in the Rome area and not occupationally exposed to mineral dust. L. Paoletti, D. Batisti, S. Caiazza, et al. 1987;44(1):18-28. PubMed · Publisher

Abstract

We studied the inorganic particulate contained in the lung parenchyma of 10 subjects (5 males and 5 females) resident in an urban area and not occupationally exposed to dusts. A total of 17 mineral types were identified, along with 16 metal elements in the form of oxides and sulfides. Approximately 70% of the minerals were made up of phyllosilicates, in particular clay, mica, and talc; three metal elements, Fe, Al, and Ti, accounted for more than 75% of the recovered oxide particles. The mean concentration of the observed inorganic particles was approximately 1.8 X 10(5) pp/mg dry tissue. No significant differences were observed in terms of total particulate concentration in the various areas of the lungs and between the right and left lung. Instead we observed a larger concentration of fibrous particles in the upper lobes. The analysis of the data made it possible to determine the presence of a high degree of correlation between the concentrations of silicates and the concentrations of metal oxides and sulfides, implying the existence of a ubiquitous environmental source of these mineral particles. The frequent observation of tremolite fibers is remarkable. This finding, confirmed elsewhere, indicates that the magnitude of the sources of these fibers in the environment, constituted by contaminated talc dusts, has been underestimated until today.
Prevention of asbestos-induced cell death in rat lung fibroblasts and alveolar macrophages by scavengers of active oxygen species. M.A. Shatos, J.M. Doherty, J.P. Marsh, et al. 1987;44(1):103-16. PubMed · Publisher

Abstract

Cell injury and inflammation caused by asbestos are critical to the pathogenesis of pulmonary fibrosis (asbestosis). Our goal in studies here was to investigate the possible modulation of asbestos-related cell death using antioxidants in both target and effector cells of asbestosis. After exposure to crocidolite asbestos at a range of concentrations (2.5-25 micrograms/cm2 dish), the viability of a normal rat lung fibroblast line (RL-82) and freshly isolated alveolar macrophages (AM) was determined by exclusion of trypan blue and nigrosin, respectively. In comparison to fibroblasts, AM were more resistant to the cytotoxic effects of asbestos. Cytotoxic concentrations of asbestos then were added to both cell types in combination with the antioxidants, superoxide dismutase (SOD), a scavenger of superoxide (O2-.), and catalase, an enzyme scavenging H2O2. Dimethylthiourea (DMTU), a scavenger of the hydroxyl radical (OH.) and deferoxamine, an iron chelator, also were evaluated in similar studies. Results showed significant dosage-dependent reduction (P less than 0.001) of asbestos-associated cell death with all agents. In contrast, asbestos-induced toxicity was not ameliorated after addition of chemically inactivated SOD and catalase or bovine serum albumin. Results above suggest asbestos-induced cell damage is mediated by active oxygen species. In this regard, the iron associated with the fiber and/or its interaction with cell membranes might be critical in driving a modified Haber-Weiss (Fenton-type) reaction resulting in production of OH(.).
Sepiolite asbestos from Franklin, New Jersey: a case study in medical geology. M. Germine. 1987;42(2):386-99. PubMed · Publisher

Abstract

Asbestiform sepiolite has been found in a zinc deposit at Franklin, New Jersey. The host rock is Precambrian Franklin marble. Pseudomorphous foliated texture and cross-cutting relationships indicate replacement of talc by sepiolite. Sepiolite is manganoan, while talc contains little manganese, suggesting differences in manganese substitution in these minerals and providing evidence against solid-state replacement. Sepiolite from Franklin is of moderate crystallinity and consists of soft, flexible mass-fiber. Comparison with other sepiolite samples suggests that increased crystallinity among sepiolites parallels increased fiber length, while disorder appears to be associated with flexibility. Length and aspect ratio (length/width) distributions support toxicological equation of asbestiform sepiolite with the regulated asbestos minerals. The data presented here suggest that talc can be unstable in a low-temperature hydrothermal environment, altering under certain conditions to form sepiolite. In a wider context, sepiolite may be expected to precipitate at the end-stages of hydrothermal mineralization in some talc deposits and in carbonate and calc-silicate rocks. Many occurrences of sepiolite in these rocks may have been overlooked due to similarities with other minerals. The fact that sepiolite has been previously unrecognized and misidentified at Franklin is a case in point. Since there is evidence suggesting that sepiolite is fibrogenic and carcinogenic, its potential occurrence in consumer talcs and crushed-stone products has environmental health implications. Similarities in composition and other analytical parameters may cause sepiolite to be mistaken for fibrous talc or chrysotile in environmental samples.
Some biological properties of respirable iron ore dust. D. Keast, N.P. Sheppard, J.M. Papadimitriou. 1987;42(2):455-68. PubMed · Publisher

Abstract

The respirable fraction of an ore dust from the North-West of Western Australia was tested for biological properties by inhalation and intrapleural implantation trials using rats and mice. Pulmonary histology indicated significant levels of interstitial pneumonia occasionally associated with bronchopneumonia, bronchiectasis, emphysema, and lung collapse over that found in age-matched control animals. While there was a significant increase of the incidence of tumors in general in WAG inbred rats up to 2 years following dust exposure, this did not persist into old age. No mesotheliomas were induced by any treatments associated with iron ore dust, although the rats were shown to be susceptible to crocidolite asbestos-induced mesothelioma. In the mouse models, tumors which are normally seen only in aged animals were induced with a significant number of bronchial adenomas being recorded following intrapleural implantation of dust into inbred BALB/c mice. Leukemia/lymphoma associated with murine leukemia virus was increased following dust inhalation by inbred C57BL mice.
Stimulation of alveolar macrophages by mineral dusts in vitro: luminol-dependent chemiluminescence study. V. Vilím, J. Wilhelm, P. Brzák, et al. 1987;42(1):246-56. PubMed · Publisher

Abstract

Luminol-dependent chemiluminescence (CL) of normal (nonactivated) rabbit alveolar macrophages (AMs) was measured in suspension upon stimulation by various size fractions of one quartz dust sample or by various mineral dusts (quartz, corundum, anatas, and chrysotile asbestos as an example of fibrous dust). The CL-triggering capacity of the tested dusts was inhibited by their preincubation with autologous serum. The intensity of luminol-dependent CL induced by particulate dusts upon their action on AMs depended on the kind of dust, on the dust particle sizes, and on the ratio of the number of particles to the number of cells in a given suspension. The cytotoxicity and/or fibrogenicity of the dust and its capacity to trigger the luminol-dependent CL of nonadherent AMs were not directly correlated.
The lung biological activity of American attapulgite. R. Bégin, S. Massé, M. Rola-Pleszczynski, et al. 1987;42(2):328-39. PubMed · Publisher

Abstract

Attapulgite is a fibrous mineral industrially consumed at the rate of over a million tons per year but the biological activity of the material is not fully known. To evaluate the in vivo toxicity of the fibrous material, we exposed the tracheal lobe of 16 sheep to a single exposure of either 100 ml saline, 100 mg UICC asbestos fibers in 100 ml saline, 100 mg short asbestos fibers in 100 ml saline, or 100 mg attapulgite in 100 ml saline. The animals were studied by bronchoalveolar lavage (BAL) at Days 2, 12, 24, 40, and 60 and by autopsy at Day 60. In the saline-exposed sheep, BAL and lung histology did not change. In the UICC asbestos-exposed animals, we reproduced the BAL changes previously reported (R. Bégin, M. Rola-Pleszczynski, S. Massé, Y. Berthiaume, and G. Drapeau, 1985, Environ. Res. 36, 389-404). In the short asbestos-exposed sheep, there were no significant BAL changes. In the attapulgite sheep, we found significant and sustained increases in total BAL cells (X2, P less than 0.05), macrophages (X2, P less than 0.05), neutrophils (X5, P less than 0.01), fibronectin (X2-3, P less than 0.05), lactate dehydrogenase (X2, P less than 0.05), beta-glucuronidase (X2, P less than 0.05), but BAL cellularity returned to control levels by Day 60 whereas in the UICC asbestos-exposed sheep, it remained significantly above control. Lung histology demonstrated the characteristic peribronchiolar fibrosing alveolitis in the UICC asbestos-exposed sheep, whereas macrophagic alveolitis with minimal airway distortion was seen in the short asbestos-exposed sheep and in all of the attapulgite-exposed sheep but three which had typical peribronchiolar alveolitis quite similar to that observed in UICC-exposed sheep, but of lower intensity. In conclusion, the study documents that attapulgite is not an inert material for lung tissue; it does produce a macrophagic and neutrophilic alveolitis in the early inflammatory phase of lung reaction with peribronchiolar involvement in some sheep. Whether or not this initial attapulgite induced alveolitis leads to lung fibrosis remains to be evaluated in a longer follow-up study of attapulgite-exposed animals.
Types, numbers, sizes, and distribution of mineral particles in the lungs of urban male cigarette smokers. A. Churg, B. Wiggs. 1987;42(1):121-9. PubMed · Publisher

Abstract

We analyzed the exogenous mineral particle concentration, size, type, and distribution for particles larger than 0.1 micron in the left lungs of 10 long-term male cigarette smokers. The mean number of particles found was 465 +/- 295 X 10(6)/g dry lung, of which 80% were kaolinite, micas, feldspars, free silica, and talc. Lead particles were extremely rare, despite their ubiquity in urban air. Overall there were no differences in particle concentration in upper vs lower lobes or central vs peripheral sampling sites. However, a significant correlation was found for upper lobe (r = 0.68), but not lower lobe (r = 0.08), particle concentration and amount of cigarette smoking. Overall, the geometric mean particle size was 0.6 +/- 2.1 microns; 56% of the particles in the upper lobes were larger than 0.75 micron in diameter, compared to 17% in the lower lobes, and the mean upper lobe particle size was greater than the mean lower lobe particle size for all individual mineral types. There was a remarkable homogeneity of mean particle size from patient to patient (mean intercase arithmetic particle size +/- SD of 0.8 +/- 0.1 micron). Particle size was not affected by the amount of smoking. We conclude that contrary to some published acute deposition data, there are no long-term differences in upper vs lower lobe particle concentration; total upper lobe particle retention is influenced by the amount of smoking as measured by pack-years, whereas total lower lobe particle retention appears to be independent by the amount of smoking; particles retained in the upper lobe are somewhat larger than those retained in the lower lobe, but the amount of smoking does not appear to influence retained particle size; the size of long-term retained particles most likely reflects largely atmospheric particle burden; and in the absence of overwhelming dust loads, the lung is able to regulate retained particle concentration and size in a fairly narrow range.
Asbestos bodies and the diagnosis of asbestosis in chrysotile workers. J. Holden, A. Churg. 1986;39(1):232-6. PubMed · Publisher

Abstract

It has been suggested that because chrysotile asbestos forms asbestos bodies poorly, use of the traditional histologic requirements (diffuse interstitial fibrosis plus asbestos bodies) for the diagnosis of asbestosis, may lead to an underdiagnosis of this condition in workers exposed only to chrysotile. We examined lungs from 25 chrysotile miners with diffuse interstitial fibrosis. Asbestos bodies were found easily in histologic section using hematoxylin and eosin stains in all cases. Mineralogic analysis of four cases showed that 46 of 72 (64%) bodies isolated and examined contained chrysotile cores, and 21 of 72 (29%) bodies contained cores of the amphiboles tremolite and actinolite. By contrast, tremolite and actinolite constituted the majority of uncoated fibers in these cases. The mean length for bodies formed on chrysotile was 35 micron, and for bodies formed on tremolite or actinolite, 36 micron. We conclude that (1) the usual histologic criteria for the diagnosis of asbestos are applicable to chrysotile-exposed workers; (2) in workers with occupational chrysotile exposure, bodies form readily on this mineral; and (3) asbestos bodies in these lungs reflect the presence of long asbestos fibers.
Asbestos effects on superoxide production. An in vitro study of hamster alveolar macrophages. B.W. Case, M.P. Ip, M. Padilla, et al. 1986;39(2):299-306. PubMed · Publisher

Abstract

Inhaled asbestos induces accumulation of alveolar macrophages (AM) and polymorphonuclear leukocytes (PMN) in lung. Asbestos-enhanced production of superoxide anion (O2-) by AM and/or PMN may be involved in the pathogenesis of asbestos-induced fibrosis, either through direct effects on collagen synthesis or via mediation of tissue injury and repair. In in vivo experiments, bronchoalveolar lavage (BAL) 3 to 8 weeks following intratracheal asbestos injections showed increases in both PMN and AM, with AM representing 78 to 82% of cells recovered. Inhalation models, generally regarded as more analagous to human exposures, have confirmed AM as the predominant component of the cellular response to inhaled asbestos. In this study, the in vitro effects of asbestos fiber on O2- production by AM have been determined in cell populations derived from the Syrian golden hamster. AM for in vitro study were obtained by BAL. O2- production was monitored as superoxide dismutase (SOD) - inhibitable cytochrome c reduction. Significant rises in O2- release by AM were noted in the presence of 0.4 mg/ml crocidolite (2.53 +/- 0.33 nmole cytochrome c reduced/10(6) cells/30 min, 37 degrees C; controls 1.13 +/- 0.18 nmole; P less than 0.02). Chrysotile induced levels of O2- release in AM which were similar to those evoked by crocidolite.
Asbestos fibers and trace metals in the blood of cattle grazing in fields inundated by asbestos-rich sediments. H. Schreier, J.A. Shelford, T.D. Nguyen. 1986;41(1):99-109. PubMed · Publisher

Abstract

During a major storm in 1975, a pasture was inundated with serpentinitic sediments which are rich in asbestos fibers and trace metals. Little natural revegetation has occurred at the site and dairy and beef cattle which continue to graze in and around the contaminated site are exposed to asbestos fibers by inhalation and ingestion. The effect of this material on the cattle was investigated in this study by analyzing blood samples from exposed and control animals for asbestos fibers, trace metals, and general blood chemistry. The analysis showed that at the time of exposure Ni and Mn values were significantly higher in the exposed animals than in the controls, and in six out of seven samples asbestos fibers were present as determined by STEM analysis. Once the animals were removed from the site, trace metal levels returned to normal but asbestos fibers were still present in three out of seven animals. Two of the control animals unaffected by the sediments also showed asbestos fibers and there were no relationships between the magnitude of fibers and trace metal content. This suggests that the sediments influence the blood chemistry of animals but the presence and magnitude of asbestos fibers in the blood can be influenced by other factors as well.
Coinhibition of viral interferon induction by benzo[a]pyrene and chrysotile asbestos. N. Hahon, J.A. Booth. 1986;40(1):103-9. PubMed · Publisher

Abstract

Benzo[a]pyrene (B[a]P) and its noncarcinogenic analog, benzo[e]pyrene (B[e]P), each in combination with chrysotile, were studied for their inhibitory effects on interferon (IFN) induction by influenza virus in rhesus monkey kidney (LLC-MK2) cell monolayers. B[a]P alone had no adverse effect on IFN induction; however, from 60 to 70% inhibition of IFN production occurred when B[a]P was enzymatically activated by rat liver S9. Chrysotile's inhibitory effect on the IFN process was similar in magnitude to that of activated B[a]P. The combination of activated B[a]P with chrysotile resulted in coinhibition of IFN induction which significantly exceeded (P less than 0.05) the inhibitory activity of the reagents tested alone or in other combinations. B[e]P alone or with S9 neither affected IFN induction nor was it capable of further enhancing chrysotile's inhibition of IFN synthesis. These findings provide further evidence of enhanced deleterious action by the combination of asbestos and activated B[a]P on a biological defense mechanism and further support the discriminatory power and credibility of the inhibition IFN induction assay for evaluating potential carcinogens.
Effect of chrysotile asbestos fibers on germ cells of mice. P. Rita, P.P. Reddy. 1986;41(1):139-43. PubMed · Publisher

Abstract

An Indian form of chrysotile asbestos procured from a local asbestos factory (Hyderabad) was tested for its toxic effects on spermatocytes and sperm of mice. Swiss albino male mice were fed orally with chrysotile asbestos suspended in water. The concentration tested was 20 mg/kg/day. Chronic oral administration of chrysotile failed to induce chromosomal aberrations and abnormal sperms in mice.
Effects of asbestos fibers on alveolar macrophage-mediated lymphocyte cytostasis. B.E. Bozelka, P. Sestini, Y. Hammad, et al. 1986;40(1):172-80. PubMed · Publisher

Abstract

Prolonged asbestos inhalation results in pulmonary inflammation and fibrosis. Since alveolar macrophages are active in regulation of immune responses in lung and appear to be involved in the pathogenesis of asbestosis, we evaluated the effects of asbestos exposure on the ability of these cells to regulate lymphocyte function. Alveolar macrophages obtained by lung lavage from BALB/C mice were treated in vitro with either UICC amosite or chrysotile asbestos and the effects on lymphocyte cytostasis compared with those of macrophages incubated with latex beads or zymosan. Macrophages (10%) incubated either alone or with latex beads for 48 hr effectively inhibited lymphocyte mitogenesis. However, alveolar macrophages incubated with either amosite or chrysotile asbestos did not demonstrate intact cytostatic activity. Decreased viability of chrysotile asbestos-treated macrophages correlated with loss of cytostatic effects, but alveolar macrophages exposed to amosite remained viable. We conclude, therefore, that exposure of alveolar macrophages to asbestos can result in loss of their ability to down-regulate lymphocyte proliferation, a finding which may be important in the pathogenesis of asbestos-related disease.
Effects of asbestos fibers on cell division, cell survival, and formation of thioguanine-resistant mutants in Chinese hamster ovary cells. K. Kenne, S. Ljungquist, N.R. Ringertz. 1986;39(2):448-64. PubMed · Publisher

Abstract

The ability of crocidolite fibers to induce point mutations and mitotic abnormalities in Chinese hamster ovary (CHO) cells was examined in cell cultures. The purpose has been to study the possibilities for establishing in vitro test methods to quantify genetic damage induced by asbestos and other mineral fibers. Results obtained with the CHO/hypoxanthine guanine phosphoribosyl transferase system indicated that crocidolite fibers per se do not significantly increase the number of thioguanine-resistant mutants. Crocidolite fibers also failed to potentiate the mutagenicity of benzo[a]pyrene. Time-lapse cinematography and microscopy showed that asbestos (crocidolite) fibers were markedly cytotoxic. Among surviving cells some underwent abnormal cell divisions which resulted in multi- and micronucleate cells. Many cells that contained a few asbestos fibers, however, underwent mitosis and successfully formed two mononucleate daughter cells capable of further divisions. Individual, fiber-containing cells were examined by time-lapse television recordings for 4-5 days. During this time period some cells underwent six divisions and generated an almost normal number of daughter cells. Cells which contained fibers that were longer or equivalent to the diameter of the mitotic cell (20 microns), showed different forms of mitotic abnormalities. The frequency of multinucleate cells was drastically increased following exposure to asbestos fibers. Only rarely, however, did these cells divide to produce viable daughter cells capable of continued cell multiplication. The frequency of multinucleate cells was dependent on the dose of exposure to asbestos fibers and could possibly be used as an index of the degree of mitotic disturbances induced by mineral fibers.
Effects of chrysotile asbestos on coho salmon and green sunfish: evidence of behavioral and pathological stress. S.E. Belanger, K. Schurr, D.J. Allen, et al. 1986;39(1):74-85. PubMed · Publisher

Abstract

The effects of chrysotile asbestos on larval coho salmon (Oncorhynchus kisutch) and juvenile green sunfish (Lepomis cyanellus) were investigated at levels approximating those reported in the Great Lakes basin (10(6) fibers/liter). Behavioral stress effects, such as loss of rheotaxic position and balance, were observed in salmon exposed at 3.0 X 10(6) fibers/liter and in sunfish exposed at 1.5 and 3.0 X 10(6) fibers/liter. Coho larvae at 1.5 X 10(6) fibers/liter were significantly more susceptible to an anesthetic stress test, becoming ataxic and losing equilibrium faster than control cohorts (P less than 0.001). Two of 106 larvae exposed at 3.0 X 10(6) fibers/liter developed tumorous swellings and three additional fish developed coelomic distentions. Cytological examination of ventral epidermal tissue revealed cellular histolysis, and evidence by transmission electron microscopy confirmed the presence of asbestos in the salmon larvae. Distortion of the lateral line region in asbestos-treated coho salmon was linked to behavioral and orientational aberrations. Differential mortality was not observed between control and treated groups of either test species.
Effects of the inhalation of dusts from calcium silicate insulation materials in laboratory rats. R.E. Bolton, J. Addison, J.M. Davis, et al. 1986;39(1):26-43. PubMed · Publisher

Abstract

The effects of respirable dust from three commercially produced calcium silicate insulation materials were examined in laboratory rats by long-term inhalation and injection techniques. These calcium silicate products have been used as replacements for asbestos in the insulation of the engine rooms of ships, and the particle size distribution of the dust clouds generated for the experimental study closely matched those found in ships during the installation of this type of material. One year of exposure to a dust cloud of 10 mg/m3 of respirable dust had no discernible effect on the length of survival of treated animals compared to controls. No pulmonary lesions were found that appeared associated with the inhalation of calcium silicate per se, but one sample did contain significant amounts of quartz and this did produce a few small pulmonary nodules. While two small pulmonary neoplasms, one malignant and one benign, were found in dusted animals, neither was the cause of death, and the incidence was not significantly different from the control group where no tumors were found. One peritoneal mesothelioma was found in an animal from one of the inhalation groups, but this was considered to be a spontaneous tumor as none of over 100 animals injected intraperitoneally with 25 mg of calcium silicate developed these tumors. While the white blood cell count of dusted animals, compared to controls, was significantly raised in all treated groups at the end of the dusting period, these figures were within the published normal ranges for laboratory rats. It was concluded that the three tested calcium silicate products were harmless to the rats of this species at the doses tested.
Fiber contamination of vermiculites: a potential occupational and environmental health hazard. F. Moatamed, J.E. Lockey, W.T. Parry. 1986;41(1):207-18. PubMed · Publisher

Abstract

Vermiculite ores from Montana, Virginia, and South Africa have been analyzed for the presence of amphibole contamination. Fibrous actinolite was found in unexpanded Montana vermiculite ore at a maximum concentration of 2.0%. The fibers persisted in the expanded ore at a maximum concentration of 0.6%. Actinolite was also found in the Virginia vermiculite ore but at a lower concentration and mostly as cleavage fragments with low length-to-width ratios. South African ore contained rare anthophyllite fibers also with low length-to-width ratios. Vermiculite ores have the potential for amphibole contamination and can represent potential health hazards without proper occupational and environmental control measures.
Growth changes of 3T3 cells in the presence of mineral fibers. L. Dumas, M. Pagé. 1986;39(1):199-204. PubMed · Publisher

Abstract

The relationship between exposure to asbestos fibers and the development of mesothelioma or bronchial carcinoma prompted many countries to ban its use from commercial products. The biological mechanism by which asbestos induces or promotes mesothelioma or carcinoma is still unknown. In order to study the influence of fibers on the cell surface, 3T3 fibroblasts were cultured in the presence of various mineral fibers. The acute cytotoxicity produced by mineral fibers was evaluated by the trypan blue dye exclusion method; growth of 3T3 cells was measured as well as the maximum cell density at saturation. We found that growth of 3T3 cells was slower in the presence of chrysotile while light microscopy revealed an increased cellular chromogenicity and a modification of the cell-cell arrangement in the presence of this fiber. We describe an assay in which chrysotile causes an increase in the maximum cell density at saturation.
In vitro biologic responses to native and surface-modified asbestos. N. Hahon, V. Vallyathan, J.A. Booth, et al. 1986;39(2):345-55. PubMed · Publisher

Abstract

A comparative study was made of in vitro biologic responses to native chrysotile, amosite, and crocidolite and corresponding asbestos fibers whose surfaces were modified by metal oxides. Interferon induction by influenza virus was depressed by approximately 50% by all native asbestos whereas corresponding surface modified asbestos minimally affected this nonspecific cellular defense mechanism. The release of the cytoplasmic enzyme, lactate dehydrogenase (LDH), and lysosomal enzymes, beta-N-acetylglucosaminidase (beta-NAG) and beta-glucuronidase (beta-Gluc), by rat alveolar macrophages after exposure to either native or surface-modified asbestos (which is indicative of membrane damage) was monitored. Although both native and surface-modified asbestos induced significant leakage of LDH, generally, lesser amounts of the enzyme were released as a result of exposure to the latter than to native asbestos. Whereas all forms of native asbestos caused significant release of beta-NAG and beta-Gluc, leakage of these enzymes from macrophages exposed to surface-modified asbestos was minimal. In contrast to native asbestos which induced irritation of cell membranes, as indicated by hemolysis of sheep erythrocytes, surface-modified asbestos exhibited minimal hemolytic activity. The findings indicate that surface modification of different asbestos by metal oxides generally lessened the adverse effect of the native mineral on the aforementioned biologic entities.
Outcome of asbestos exposure (lung fibrosis and antinuclear antibodies) with respect to skin reactivity: an 8-year longitudinal study. A. Lange, D. Garncarek, J. Tomeczko, et al. 1986;41(1):1-13. PubMed · Publisher

Abstract

Two hundred seventy asbestos workers were examined during an 8-year period. During this time five consecutive surveys were completed. Skin tests with streptokinase-streptodornase (SK-SD), tuberculin (PPD), and phytohemagglutinin (PHA) were performed in the middle of this period. The results of these tests were related to X-ray chest film results and the appearance of antinuclear antibodies (ANA). In all surveys, except the first, X-ray films with small irregular opacities with a profusion greater than or equal to 1/1 belonged more frequently to asbestos workers who did not respond to SK-SD or PHA. Thirty-one cases of asbestosis were diagnosed at that time, 23 of them became asbestotic after the skin tests were performed. Asbestotic cases contributed more frequently to the group with anergy as compared to asbestos workers lacking asbestosis. Furthermore, asbestosis was correlated with lack of response to second strength of SK-SD in males and PHA in both sexes. Lack of response to these activators was predictive of asbestosis. Asbestos workers with ANA frequently displayed a lack of response to the first strength of SK-SD, PPD, and PHA. This was partly due to the presence of asbestotic cases in the group. However, low responders to all these activators were found more frequently in the group with ANA independent of the presence of asbestosis.
Response of perifused alveolar macrophages to glass fibers: effect of exposure duration and fiber length. G. Forget, M.J. Lacroix, R.C. Brown, et al. 1986;39(1):124-35. PubMed · Publisher

Abstract

The effect of glass fibers on rat alveolar macrophages was studied with a new perifusion technique which allows the sequential determination of cell-derived inflammatory mediators as well as estimation of cell viability and aggregation at the end of the incubation period. Our results showed that glass fibers induced dose-dependent release of prostaglandins and beta-glucuronidase from macrophages and the aggregation and death of these cells. These deleterious effects were clearly related to the length of the fibers, with the longer fibers (greater than or equal to 4-5 micron) being more active than the shorter ones (less than 3 micron). Furthermore, a short exposure of 1 hr followed by an 18-hr perifusion induced the same inflammatory and toxic effects on the macrophages as did leaving the fibers undisturbed for the complete 18-hr perifusion. It is concluded that glass fibers produce effects in cultures of rat alveolar macrophages qualitatively similar to those of asbestos, and that fiber length appears to be a critical determinant of toxicity.
Selective adsorption of serum proteins by chrysotile and crocidolite. F. Valerio, D. Balducci, L. Scarabelli. 1986;41(2):432-9. PubMed · Publisher

Abstract

Two distinct and contemporaneous adsorption mechanisms occur when serum proteins are incubated with chrysotile and crocidolite. The first one appears to be reversible and nonspecific, independent of the characteristics of the protein and the fiber surface. The second process seems to depend on fiber type and to involve only some protein species that are strongly concentrated on the fiber surface. This latter adsorption mechanism appears to be electrostatic in nature.
Solubility of asbestos and man-made mineral fibers in vitro and in vivo: its significance in lung disease. A. Morgan, A. Holmes. 1986;39(2):475-84. PubMed · Publisher

Abstract

Work on the solubility of asbestiform minerals and of man-made mineral fibers, both in vitro and in vivo, is reviewed. The significance of solubility in determining the pathogenic potential of these materials is also discussed.
Studies on surface properties of asbestos. I. Active sites on surface of chrysotile and amphiboles. L. Bonneau, H. Suquet, C. Malard, et al. 1986;41(1):251-67. PubMed · Publisher

Abstract

The study of the acid-base properties of asbestos reveals a striking analogy between amphiboles and chrysotile. The high sites' density with basic character, evidenced by use of various probe molecules, is very similar for the two asbestos types (chrysotile and crocidolite) and on the same order as the density encountered in some catalysts. Discussion of the surface structure reveals that it is the noncrypting lateral surfaces which possess an electron donor character while the surfaces of the extremities of the fibers with crypting character possess a null or very weakly positive charge.
Studies on surface properties of asbestos. II. Role of dimensional characteristics and surface properties of mineral fibers in the induction of pleural tumors. L. Bonneau, C. Malard, H. Pezerat. 1986;41(1):268-75. PubMed · Publisher

Abstract

In animal experiments, the probability that pleural tumors will develop after mineral fiber implantation is dependent upon the fiber's size. This was originally analyzed in relation to the number of injected fibers with specific dimensional characteristics and, more recently, in relation to average aspect ratio (average length/diameter ratio). New experimental data on various mineral fibers suggest that the carcinogenic potency of a solid particle depends on two parameters: the nature of the mineral and therefore the nature of active surface sites, and the aspect ratio of the particle. These two parameters can intervene in a mechanism of model reaction involving the basic properties of lateral faces of fibers.
Studies on surface properties of asbestos. III. Interactions between asbestos and polynuclear aromatic hydrocarbons. J. Fournier, H. Pezerat. 1986;41(1):276-95. PubMed · Publisher

Abstract

The purpose of this study is to reveal the nature of the physicochemical interactions between asbestos and polynuclear aromatic hydrocarbons (PAH) in an organic liquid medium, and to assist in the understanding of synergistic effects between asbestos and PAH in bronchopulmonary cancers. The adsorption curves of three PAH (phenanthrene, fluorene, dimethyl-7,12-benzanthracene) on chrysotile and crocidolite are multistep isotherms and show the formation of bidimensional condensed layers (2D) of PAH. This phenomenon is observed with solids having a dominant basic character (asbestos, magnesia) but is not detected with acidic solids (alumina, silica-alumina). The elimination of water and dissolved gases (O2, CO2) in the liquid medium increased the affinity of asbestos for PAH. The coadsorption CO2-phenanthrene on the substrate decreased the adsorbed quantities of solute but did not inhibit the formation of layers (2D). The adsorption is weaker on leached chrysotile, than on original chrysotile; the amorphous silica coating the fibers has no affinity for PAH; the adsorption is only due to some active sites present on the surface of residual chrysotile which is accessible to phenanthrene. The formation of layers (2D) is due to strong interactions between PAH having an induced or permanent dipole moment and the active electron donor sites present on the mineral surface. The equilibrium equation between the adsorbed layer and the PAH in solution is established by reference to theoretical studies, and the results allowed us to classify the charge density of the mineral surface. The interactions between PAH and asbestos allowed us to explain the differences introduced in the kinetics of PAH uptake toward the cells when PAH is preadsorbed on asbestos. This fact could, in part, explain the synergistic effects observed in carcinogenesis.
Studies on surface properties of asbestos. IV. Catalytic role of asbestos in fluorene oxidation. R. Zalma, J. Guignard, E. Copin, et al. 1986;41(1):296-301. PubMed · Publisher

Abstract

To determine whether asbestos is a basic catalyst, catalytic oxidation of fluorene to fluorenone in a heterogeneous system was tested. It was shown that oxidation was quantitatively possible on the surface of all basic minerals, such as asbestos (chrysotile and crocidolite) and magnesia, but was not possible with acidic mineral materials such as silica. The effects of different factors are discussed.
The adsorption of polyaromatic hydrocarbons on natural and chemically modified asbestos fibers. H. Menard, L. Noel, J. Khorami, et al. 1986;40(1):84-91. PubMed · Publisher

Abstract

Many reports indicate that the carcinogenic (genotoxic) potential of benzo[a]pyrene (B[a]P) may be enhanced several-fold by the promoter (epigenetic) effect of asbestos particles. This promoting effect could be related to the fact that when B[a]P is adsorbed onto the particles, there is a resulting enhanced transport and uptake of the carcinogen into microsomial membranes. These in vitro data bear relevance to the epidemiological studies which indicate an association between exposure to inhaled asbestos dusts and the high incidence of pulmonary cancers in smokers. Using HPLC, it has been observed that B[a]P has great affinity for natural asbestos fibers, and that chemical modification of natural chrysotile with POCl3 results in the complete loss of this adsorption potential of chrysotile for benzo[a]pyrene.
Airborne asbestos in Colorado public schools. D.A. Chadwick, R.M. Buchan, H.J. Beaulieu. 1985;36(1):1-13. PubMed · Publisher

Abstract

Levels of airborne asbestos for six Colorado public school facilities with sprayed-on asbestos materials were documented using three analytical techniques. Phase contrast microscopy showed levels up to the thousandths of a fiber per cubic centimeter (f/cc), scanning electron microscopy (SEM) up to the hundredths of a f/cc, and transmission electron microscopy coupled to selected area electron diffraction and energy dispersive X-ray analysis (TEM-SAED-EDXA) up to the tenths of an asbestos f/cc. Phase contrast microscopy was found to be an inadequate analytical technique for documenting the levels of airborne asbestos fibers in the schools: only large fibers which were not embedded in the filter were counted, and asbestos fibers were not distinguished from nonasbestos.
Airborne fiber control in buildings during asbestos material removal by amended water methodology. R.N. Sawyer, A.N. Rohl, A.M. Langer. 1985;36(1):46-55. PubMed · Publisher

Abstract

Removal of friable asbestos-containing material can cause high levels of airborne contamination. The potential efficacy of control methods recommended by the Environmental Protection Agency (EPA) was evaluated by examination of 503 air samples obtained in 40 removal projects in a number of locations. The EPA methodology with amended water for fiber emission control was utilized on all of the observed removal projects. The projects were also considered to be well controlled and the study cannot be considered representative of common work practices. The EPA amended water methodology, when effectively utilized and administered, can provide a high degree of contamination control. Mean fiber levels in the work area in this study (1.1 f/cm3) were well below those of dry removal (38.9 f/cm3) and control by application by untreated water (28.6 f/cm3). Airborne contamination was higher during bagging debris (3.8 f/cm3) than during material removal from structural surfaces. The range of fiber levels during removal was 0.0 to 37.0 f/cm3 and fibers were detected from initial barrier construction through final cleaning. Contamination was also occasionally detected outside work area containment barriers. Air sampling produced 0.0 counts in areas of obvious contamination by settled dust and debris. Control methodologies, respiratory protection, and decontamination are discussed.
Ambient air concentrations of asbestos fibers near the town of Asbestos, Québec. B. Singh, J.P. Thouez. 1985;36(1):144-59. PubMed · Publisher

Abstract

Ambient air concentrations of asbestos fibers were measured during the period June 20 to August 12, 1980, at three locations; Danville, Asbestos, and Wottenville in the eastern townships of Quebec. Measurements were done with low-volume samplers and measurement periods extended from 3 to 13 days. Fiber counts were done by means of electron microscopy. Results indicate that overall fiber concentrations are related to atmospheric stability and to the direction of the prevailing wind with respect to the source of emission.
An assessment of the fibrogenic potential of very short 4T30 chrysotile by intratracheal instillation in rats. I. Lemaire, D. Nadeau, J. Dunnigan, et al. 1985;36(2):314-26. PubMed · Publisher

Abstract

Three groups of five rats each received, respectively, a single intratracheal instillation of saline (control), 5 mg of UICC chrysotile B asbestos, and 5 mg of a preparation of very short chrysotile fibers (4T30, 100% less than 8 micron) isolated by a sedimentation procedure. At various intervals after the treatment (1 to 60 days), assessment of lung morphology was performed on each animal. Although the two types of chrysotile fibers have similar chemical composition, structure, and surface charge, the lung tissue reaction differed considerably. Lungs of animals exposed to UICC chrysotile B showed significant pathological alterations as early as 7 days following treatment. The lesions were localized in and around terminal bronchioles and consisted of inflammatory cells, fibroblasts and collagen deposition which distorted and obstructed small airways. Reaction to very short 4T30 chrysotile fibers was quite distinct. Seven days after treatment, lungs of these animals showed alveolar and interstitial accumulation of inflammatory cells. The alveolitis persisted 60 days after treatment and no fibrosis was apparent. It appears that very short 4T30 chrysotile fibers are much less fibrogenic than UICC chrysotile B and that intratracheal instillations in rats may represent a useful mean of rapidly assessing the fibrogenic potential of various dusts. These observations support the concept that fiber length is an important factor for fibrogenicity of asbestos.
Asbestos-induced decomposition of hydrogen peroxide. M.K. Eberhardt, A.A. Román-Franco, M.R. Quiles. 1985;37(2):287-92. PubMed · Publisher

Abstract

Decomposition of H2O2 by chrysotile asbestos was demonstrated employing titration with KMnO4. The participation of OH radicals in this process was delineated employing the OH radical scavenger dimethyl sulfoxide (DMSO). A mechanism involving the Fenton and Haber-Weiss reactions as the pathway for the H2O2 decomposition and OH radical production is postulated.
Calculated solubility of chrysotile asbestos in physiological systems. W.T. Parry. 1985;37(2):410-8. Review PubMed · Publisher

Abstract

Chrysotile asbestos fibers which are ingested into a physiological system will dissolve in fluids to which they are exposed. The rate of dissolution can be estimated by formulating an appropriate rate law and retrieving rate constants from published experiments. The rate of dissolution calculated for asbestos fibers is dependent on the surface area of dissolving mineral, mass of solution to which the fibers are exposed within cells, the rate of transport of H+ into the cells, and the rate of transport of Mg2+ and SiO2 out of the cells. The maximum rate of dissolution of a single 10-micron X 1-micron fiber within a cell is 2.13 X 10(-7) moles hr-1 kg-1 consistent with dissolution rates measured in vivo by Morgan et al. (A. Morgan, A. Holmes, and C. Gold. Studies of the solubility of constituents of chrysotile asbestos in vivo using radioactive tracer techniques. Environ. Res. 4, 558-570, 1971).
Circulating immune complexes in asbestos workers. J.J. Zone, W.N. Rom. 1985;37(2):383-9. PubMed · Publisher

Abstract

Circulating immune complexes, rheumatoid factor, and antinuclear antibodies were evaluated in 25 asbestos insulation workers and 32 brick mason controls. There were 10 asbestos workers with radiographic parenchymal or pleural changes, consistent with their asbestos exposure. There were no differences in antinuclear antibodies or rheumatoid factor between asbestos workers and controls. The asbestos workers had significantly increased levels of IgG and IgA circulating immune complexes. There was a significant correlation between IgA circulating immune complexes and radiographic changes.
Inhalable particles and pulmonary host defense: in vivo and in vitro effects of ambient air and combustion particles. G.E. Hatch, E. Boykin, J.A. Graham, et al. 1985;36(1):67-80. PubMed · Publisher

Abstract

The ability of particulate air pollutants (and possible constituents) to alter pulmonary host defenses was examined using an in vitro alveolar macrophage cytotoxicity assay and an in vivo bacterial infectivity screening test which employed intratracheal injection of the particles. A wide range of response between particles was seen at the 1.0-mg/ml level in vitro and the 0.1-mg/mouse level in vivo. A sample of fluidized-bed coal fly ash, bentonite, asbestos, some ambient air particles, and heavy metal oxides greatly increased susceptibility to pulmonary bacterial infection. Most coal fly ash samples and some air particles caused moderate increases in infectivity, while diesel particulates, volcanic ash, and crystalline silica caused only small increases. Cytotoxic effects on macrophages in vitro were observed with most of the particles. The in vivo and in vitro assays produced a similar ranking of toxicity; however, not all particles that were highly cytotoxic were potent in increasing bacterial infectivity. Increased toxicity measurable by either assay often appeared to be associated with small size or with the presence of metal in the particles.
Metallic elements in crude and milled chrysotile asbestos from Quebec. C. Barbeau, M. Dupuis, J.C. Roy. 1985;38(2):275-82. PubMed · Publisher

Abstract

Crude and milled fibers from different asbestos mines in Quebec have been analyzed for their metallic content. Crude fibers present a few metal concentrations that are characteristic for each mine. Manganese and iron can be used as discriminators, zinc and cobalt are constantly present in minute quantities, and calcium is virtually absent from crude fibers. Milled fibers are enriched in metals by factors ranging from 1.3 to greater than 15. Chromium and nickel concentrations are many times higher than in crude fibers and iron content is increased by more than 100%. Total metal content in milled fibers is mainly due to nonchrysotile material.
Metsovo lung: pleural calcification and restrictive lung function in northwestern Greece. Environmental exposure to mineral fiber as etiology. S.H. Constantopoulos, J.A. Goudevenos, N. Saratzis, et al. 1985;38(2):319-31. PubMed · Publisher

Abstract

Pleural calcifications are described in 122 of 268 (45.5%) inhabitants of four villages (Metsovo, Anilio, Milea, and Votonosi) in a small area of northwestern Greece (total population about 5000). All affected individuals are of one ethnic group, Vlachi. Calcifications were not noted in any of the 103 persons in the control group made up of 73 non-Vlachi inhabitants from the same and neighboring villages and 30 Vlachi from distant villages. The calcifications were seen in both sexes, equally, and their frequently increased with age, from 28.6% between 30 and 39 years to 81.0% in individuals over 70 years of age. When plaque development was extensive, a small restrictive pulmonary function defect was noted. Because of its prevalence in the Metsovo area we call this clinical pattern Metsovo lung. The identification of tremolite, related amphibole fibers, and traces of chrysotile fiber in settled dusts and soil specimens and of identical fibers in tissue specimens obtained at lung biopsy from 8 people with plaques supports the hypothesis that abestiform minerals are the agents responsible for these disease processes. Further, reports of the occurrence of mesothelioma and benign pleural effusions in inhabitants in the Metsovo area, along with the striking similarities to disease patterns observed in the Karain area of Turkey, add further weight to the hypothesis that mineral fiber(s) in the environment of the four villages are agent(s) in the etiology of Metsovo lung.
Mineral particles, mineral fibers, and lung cancer. A. Churg, B. Wiggs. 1985;37(2):364-72. PubMed · Publisher

Abstract

The total fibrous and nonfibrous mineral content of the lung has been analyzed in a series of 14 men with lung cancer but no history of occupational dust exposure, and in a series of 14 control men matched for age, smoking history, and general occupational class. The lung cancer patients had an average of 525 +/- 369 X 10(6) exogenous mineral particles and 17.4 +/- 19.6 X 10(6) exogenous mineral fibers/g dry lung, while the controls had averages of 261 +/- 175 mineral particles and 4.7 +/- 3.2 X 10(6) mineral fibers/g dry lung. These differences are statistically significant for both particles and fibers. Kaolinite, talc, mica, feldspars, and crystalline silica comprised the majority of particles of both groups. Approximately 90% of the particles were smaller than 2 micron in diameter and approximately 60% smaller than 1 micron; the mean particle size in the cancer group was 1.1 +/- 0.2 micron and in the control group 1.3 +/- 0.2 micron. In both groups, patients who had smoked more than 35 pack years had greater numbers of particles than patients who had smoked less than 35 pack years. It is concluded that, in this study, lungs from patients with lung cancer had statistically greater numbers of mineral particles and fibers than lungs from controls, and that smoking influences total long-term retention of particles from all sources.
Physicochemical characterization of cryogenically ground, size separated, fibrogenic particles. P.S. Thorne, E.N. Lightfoot, R.M. Albrecht. 1985;36(1):89-110. PubMed · Publisher

Abstract

A method for cryogenically grinding and separating (by size) fibrogenic minerals in the 1-micron size range is described and verified for chrysotile asbestos, quartz, forsterite (an olivine), and tantalum with a battery of analytical tests. Through use of energy dispersive X-ray spectroscopy, neutron activation analysis, X-ray photoelectron spectroscopy, and X-ray diffraction analysis it is shown that the grinding and separation procedure described does not alter the mineral composition, preserves the trace element composition, maintains the surface composition, and preserves the crystalline structure. Further, investigation of electrokinetic properties of these dusts by electrophoretic quasielastic light scattering is described. The small size dispersity of these samples facilitates use of this technique for the determination of the apparent electrokinetic charge and estimations of surface charge density at ionic strengths below physiological. It is suggested that analyses of the type described here be an integral part of studies of the fibrogenic, immunologic, or toxicologic properties of such minerals. This work has been performed in conjunction with the authors' studies of the effects of these particulates on macrophage ultrastructure and immunologic function in vitro.
Pleural calcification in northwest Greece. T. Bazas, D. Oakes, J.C. Gilson, et al. 1985;38(2):239-47. PubMed · Publisher

Abstract

Mass miniature radiography in 1969 detected a high prevalence of pleural calcification in three villages in northwest Greece. In 1980 a survey of a 15% sample of the population over the age of 10 was carried out with a 80% response rate. Full-size radiographs, ventilatory capacity measurements, and a detailed questionnaire on respiratory symptoms, type of work, and residence were used. Independent classification of the 408 films by two readers using the ILO/UC scheme showed very few small opacities but a very high prevalence of pleural calcification first evident in young adults and rising to 70% in the elderly. The overall prevalence was 34.7% in men and 21.5% in women. A comparison with the 1969 survey showed a progression rate of 5% per annum. In neither sex was there a significant relation of pleural calcification to smoking, ventilatory capacity, nor type of work, though those classified as field croppers had a slightly higher prevalence. There was no obvious evidence of increased lung cancer or mesothelioma in the villages. The agent responsible for this apparently benign condition was not identified.
Selective exposure and analysis of the sheep tracheal lobe as a model for toxicological studies of respirable particles. R. Bégin, S. Massé, M. Rola-Pleszczynski, et al. 1985;36(2):389-404. PubMed · Publisher

Abstract

A conscious sheep model, recently developed to study sequentially the bronchoalveolar milieu, was further refined to use in the rapid in vivo assessment of the biological effects of respirable particles. In this model, the anatomically isolated tracheal lobe was selectively exposed to either 100 ml phosphate buffered saline (PBS) (control group of 12 sheep), 100 mg of 0.1-micron latex beads in 100 ml PBS (latex group of 12 sheep), or 100 mg of UICC Canadian chrysotile fibers in 100 ml PBS (asbestos group of 12 sheep). Bronchoalveolar lavages (BAL) of the tracheal lobe were obtained prior to exposure and at Days 1, 8, 15, 21, 29, 45, and 60 after exposure. Whole-lung detailed pulmonary function tests (PFT) were performed at the same times and the histopathology of the lobe was examined in six sheep in each group at Days 29 and 60. In the control sheep, there were no significant changes over time in any of the measures, and lung morphology remained normal. In the latex group, there was no significant change in PFT, the BAL analyses documented early transient increase in cellularity (macrophages and neutrophils at Day 1) and only macrophages after; lung histology documented an early macrophagic alveolitis which decreased to less than 10% of the initial inflammatory reaction at Day 60, without other distortion of the lung and airway architecture. In the asbestos sheep, the only change in whole-lung PFT was a 10-torr fall in arterial O2 pressure. BAL analyses documented persistent increases in macrophages, neutrophils, and lactate dehydrogenase as well as increasing gamma-globulins. Lung histology revealed a macrophagic and neutrophilic peribronchiolar alveolitis at Day 30, which regressed substantially by Day 60, but persistent peribronchiolar alveolitis, early fibrosis, and severe distortion of the small airways, lesions comparable to those of early asbestosis in sheep or humans. Thus selective exposure and sequential analyses of the sheep tracheal lobe in terms of BAL histomorphology should be valuable for rapid in vivo assessment of toxicity of respirable particles.
The enigmatic asbestos body: its formation and significance in asbestos-related disease. A. Morgan, A. Holmes. 1985;38(2):283-92. PubMed · Publisher

Abstract

It is well established that many different types of fibre, both organic and inorganic, can become coated with ferritin in lung to give ferruginous bodies. The presence of such bodies is one factor which is taken into account in assessing cases with asbestos-related disease for the purpose of compensation, although their presence is only an indication of past exposure and not proof of the causative role of asbestos. In this paper, evidence relating to the formation of ferruginous bodies in human lung is reviewed, to identify factors which predispose certain types and dimensions of fibre to become coated. Work with experimental animals is also summarised to give some indication of the time course of body formation.
Asbestos-activated peritoneal macrophages release a factor(s) which inhibits lymphocyte mitogenesis. K. Donaldson, J.M. Davis, K. James. 1984;35(1):104-14. PubMed · Publisher

Abstract

Intraperitoneal asbestos injection in mice has previously been reported to elicit an activated macrophage population. In the present study supernatants from such macrophages were tested for their effect on thymocyte mitogenesis in response to concanavalin A; control supernatants were obtained from saline- and latex-elicited macrophages. Supernatants from asbestos-elicited macrophages were significantly inhibitory to thymocyte mitogenesis while saline- and latex-elicited macrophages did not release significant amounts of such activity. Asbestos-activated macrophage supernatants were inhibitory in a dose-dependent way and the activity was not secreted by macrophages from mice which had received asbestos in the long term. The inhibitory activity was partially dialysable. Supernatants prepared by treating macrophages in vitro with a lethal dose of asbestos were not inhibitory suggesting that the inhibitory activity in the supernatants of asbestos-activated macrophages did not leak from dead or dying cells. The asbestos macrophage supernatant was also significantly inhibitory to mature T-cell-enriched spleen cells but had no effect on fibroblasts, suggesting that the inhibitory effect could be lymphoid cell specific.
Asbestos-induced chemiluminescence response of human polymorphonuclear leukocytes. M. Rola-Pleszczynski, D. Rivest, M. Bérardi. 1984;33(1):1-6. PubMed · Publisher

Abstract

Products of the oxidative metabolism of polymorphonuclear leukocytes (PMN), namely hydrogen peroxide and superoxide, may play a role in tissue injury at sites of inflammation. Oxidant production by PMN was measured by the luminol-enhanced chemiluminescence (CL) of cells exposed in vitro to asbestos fibers. Human peripheral blood PMN were incubated with 1-1000 micrograms/ml of UICC chrysotile B asbestos fibers opsonized with either normal or heat-inactivated human serum. CL was measured over 210 min and revealed a peak response at 45 min; this response was delayed in comparison to control CL induced by Staphylococcus aureus (5-10 min) and represented approximately 50% of that of the latter. Although maximal CL was generated by asbestos concentrations of 100-500 micrograms/ml, significant CL was observed at concentrations as low as 0.5-1 micrograms/ml. Opsonization of asbestos fibers with heat-inactivated serum markedly depressed CL responses, suggesting that complement activation by asbestos fibers may be important in the generation of CL by PMN. In view of the previously reported accumulation of PMN in the lungs of asbestos-exposed animals, this study suggests that oxidant production by PMN may mediate some of the pathological effects of asbestos fibers.
Development of a mathematical model for predicting concentrations of small asbestos fibers. R.M. Buchan, D.C. Richardson, H.J. Beaulieu, et al. 1984;33(2):296-9. PubMed · Publisher

Abstract

The standard method of asbestos sample analysis by phase-contrast microscopy excludes fibers which are below the resolution limits of the light microscope. Electron microscopic studies revealed that fibers in these small size ranges comprise the majority of fibers in asbestos dust. This research was conducted to determine if the development of a mathematical model for predicting concentrations of small fibers (less than 5 microns length) based on phase-contrast concentrations was feasible. The model presented in this paper was evaluated for its practical utility and was determined to be of minimal value; however, it was felt that the development of a reasonably accurate model can be arrived at through continued research.
Malignant mesothelioma induced by asbestos and zeolite in the mouse peritoneal cavity. Y. Suzuki, N. Kohyama. 1984;35(1):277-92. PubMed · Publisher

Abstract

The carcinogenicity of asbestos (amosite and chrysotile) and zeolite (fibrous erionite, mordenite, and synthetic zeolite 4A) were studied in the peritoneum of 586 BALB/C male mice after a single intraperitoneal or intraabdominal wall injection. As controls, 182 mice treated with and without saline solution were used. Both asbestos types and fibrous erionite frequently produced malignant peritoneal tumors after long latency; tumors developed in 93 of 394 animals (23.6%) treated with asbestos or fibrous erionite 7 months or more after administration. All of the induced peritoneal tumors were intimately associated with marked peritoneal fibrosis, in which asbestos or erionite fibers were regularly detected. Histopathologically, 83 (73 fibrous, 9 biphasic, and 1 epithelial) of 93 were consistent with malignant mesotheliomas. Other tumors consisted of 6 plasmacytomas, 1 histiocytoma, 1 liposarcoma, 1 osteosarcoma, and 1 adenocarcinoma of the pancreas. Two of the cases of mesotheliomas were associated with plasmacytoma. In many instances, the primary site of the mesotheliomas seemed to be multiple, the favorite sites being the omentum, mesentery, serosae of the gastrointestinal and genital organs, the diaphragm, the capsule of the liver and spleen, and the abdominal wall peritoneum. In these cases, asbestos or erionite-tissue burden followed by fibrosis was frequently observed. In addition to the 93 peritoneal tumors, 3 extraperitoneal tumors (1 fibrosarcoma and 2 rhabdomyosarcomas) were induced by amosite which was probably accidentally injected into the extraperitoneal connective tissue and the striated muscle tissue of the abdominal wall, respectively. These three tumors were also intimately associated with focal fibrosis in which amosite fibers were detected. Among the three different types of zeolite, only fibrous erionite showed striking carcinogenicity and marked fibrogenicity. The erionite-induced mesotheliomas were similar to those induced by asbestos in exhibiting long latency, in gross appearance, in histology, and in close association with fibrosis. Long-term persistence of asbestos or fibrous erionite around progenitor cells of the induced tumors and the consequent fibrosis seemed to be an important precondition of the malignant transformation of the progenitor cells.
Migration of ingested asbestos. J.H. Kaczenski, W.H. Hallenbeck. 1984;35(2):531-51. PubMed · Publisher

Abstract

Tissue samples from one test and one control baboon were analyzed by transmission electron microscopy for the presence of chrysotile and crocidolite asbestos. The test animal had been gavaged with cumulative doses of 800 mg each of chrysotile and crocidolite asbestos. An earlier evaluation of these tissues led to the conclusion that ingested asbestos fibers do not penetrate the gastrointestinal tract of the baboon and migrate systemically. However, the present study involved more sensitive methodology, and penetration and migration were clearly demonstrated by the recovery of significant levels of asbestos from test stomach, heart, spleen, pancreas, and blood samples.
The distribution and characteristics of asbestos fibers in the lungs of Finnish anthophyllite mine-workers. A. Morgan, A. Holmes. 1984;33(1):62-75. Case report PubMed · Publisher

Abstract

Measurements of the concentrations and dimensions of uncoated and coated fibers in blocks of tissue taken at the periphery and elsewhere from slices of lungs obtained from two anthophyllite-mine workers are reported. A single block from the lung of a third worker was also analyzed. For the subject examined in most detail, the mean peripheral fiber concentration was greatest in the lower lobe. In the other subject there did not appear to be much variation in fiber concentration with distance from the periphery. The count median lengths of uncoated fibers ranged from about 8 to 12 micron and for coated fibers from 40 to 50 micron. It was apparent that dicing tissue samples, before hypochlorite digestion, led to fracture of the longer uncoated and coated fibers. The results are compared with similar measurements made on the lung of an insulation worker and reported previously.
The influence of amosite asbestos exposure on lung permeability. R.F. Dodson, T. Akematsu, M.G. Williams, et al. 1984;35(2):497-506. PubMed · Publisher

Abstract

The effect of amosite asbestos on permeability of the blood/air barrier in the lung was studied using an acute animal model. The ultrastructural tracer selected for the study was horseradish peroxidase which was given intravenously in animals that had been exposed intratracheally to asbestos. The acute period of study was either 1/2, 1, 2, 3, or 4 hr, or 1-7 or 14 days postexposure. The barrier in the normal lung was at the level of the alveolar epithelial lining. Leakage of exudate and tracer occurred through the altered barriers following asbestos exposure and the extent of leakage related directly to the degree of alveolitis and the asbestos present in the area. A trend toward recovery of the barrier occurred with the reestablishment of a more normal-appearing epithelial lining during the second week postexposure.
A comparative study on the hemolytic action of short asbestos fibers on human, rat, and sheep erythrocytes. J.P. Pelé, R. Calvert. 1983;31(1):164-75. PubMed · Publisher

Abstract

The hemolytic activity of short asbestos fibers isolated by a sedimentation procedure was studied using human (HRBC), rat (RRBC), and sheep (SRBC) red blood cells. The initial velocity (Vi) of hemolysis is proportional to the concentration of fibers with HRBC and RRBC, but not with SRBC. Initial velocity (Vi) is 14.30 for HRBC, 5.75 for RRBC, and 3.60 for SRBC at a concentration of 1,000 micrograms of fibers/ml. Maximum velocity (Vm) is reached at 400 micrograms/ml with HRBC and its value is 16.7. With RRBC and SRBC, Vm is reached at 600 micrograms/ml and its value is 10 and 3.6, respectively. The 50% hemolytic concentration (HC50) at 60 min of incubation is 75 micrograms/ml for HRBC, 240 micrograms/ml for RRBC, and 260 micrograms/ml for SRBC. It appears that the sensitivity against the short asbestos fibers of the three types of RBC used is in the following order: HRBC greater than RRBC greater than SRBC.
A comparison of the effects of exposure of baboons to crocidolite and fibrous-glass dusts. B. Goldstein, R.E. Rendall, I. Webster. 1983;32(2):344-59. PubMed · Publisher

Abstract

Epidemiological studies have not revealed any significant health hazards from exposure to fibrous glass and animal experiments have been inconclusive. Baboons exposed to a fibrous-glass dust cloud with size features similar to those of crocidolite asbestos developed focal peribronchiolar fibrosis with scant ferruginous body formation. The lesions were similar to those produced by crocidolite but were less extensive. No neoplasms occurred.
Acute lung response to amosite asbestos: a morphological study. R.F. Dodson, M.G. Williams, G.A. Hurst. 1983;32(1):80-90. PubMed · Publisher

Abstract

The acute morphological response to amosite asbestos in the guinea pig was studied by light microscopy and by transmission, scanning, and scanning transmission electron microscopy. Fiber identification was carried out by energy dispersive X-ray analysis. Animals were studied at postinjection intervals of 2, 4, and 12 hr and 1-7 days. Three groups of test animals were studied for each time interval. These consisted of a vascularly perfused parenchymal group and a free cell lavaged group. The information obtained was compared with saline-injected and normal control animals. The acute tissue response was characterized by intraalveolar, not interstitial, events. The early phagocytic response was shared between polymorphs and macrophages, while in the longer intervals, the macrophages were the phagocytic cell type. Packaging differences within the two types of phagocytes were seen. Endothelial stability was noted, while some edematous type I pneumocytes were observed. Fibrotic involvement was limited to some intraalveolar fibrin deposits. It is suggested that the term "free asbestos fibers" refers to an extracellular event, while intracellular fibers are coated with either a membranous sheath, a siderosome, or a classical ferruginous coating.
Asbestos bodies in a bile duct cancer after occupational exposure. M. Szendröi, L. Németh, G. Vajta. 1983;30(2):270-80. Case report PubMed · Publisher

Abstract

A case of asbestosis after 5 years of occupational asbestos exposure is presented. At the postmortem examination, cholelithiasis and a cancer developing from the cystic duct were found and identified histologically as a squamous cell carcinoma. After digesting the tumor tissue, short asbestos bodies and fragments could be identified having a similar shape as those observed in the lung. The possible role of asbestos in the carcinogenesis of the observed bile duct cancer is proposed. The digestive examination of all malignant tumors of any origin after an asbestos exposure is suggested for the identification of the possible presence of ingested asbestos fibers, and to obtain further comprehensive human pathological data.
Asbestos-induced alterations of human lymphoid cell mitogenic responses. B.E. Bozelka, H.R. Gaumer, J. Nordberg, et al. 1983;30(2):281-90. PubMed · Publisher

Abstract

Using mitogenic assays, we have investigated the short term effects of two asbestos (amosite and chrysotile) fibers on lymphocyte functions in vitro. These oppositely charged fibers produced different alterations in mitogenesis. The blastogenic responses of concanavalin-A (Con-A) and pokeweed mitogen stimulated human peripheral blood mononuclear cells (PBMN) were significantly increased by the inclusion of 6 micrograms of chrysotile to the culture media. Amosite fibers proved to be inhibitory in all tests. When PBMN were depleted of monocytes, asbestos-related alterations of Con-A responsiveness were unchanged among the remaining cells. However, the addition of chrysotile to phytohemagglutinin (PHA) cultures resulted in a significant increase of the mitogenic response. When PBMN were enriched for T lymphocytes, and again cultured with the mitogens and fibers, the Con-A response still displayed impressive enhancement with chrysotile. In contrast to an intact PBMN population, PHA-induced blastogenesis among these T-enriched lymphocytes was significantly elevated. These experiments demonstrate that asbestos can induce significant changes in the functional integrity of PBMN following a relatively short exposure time in culture.
Asbestos-induced lung injury in the sheep model: the initial alveolitis. R. Bégin, M. Rola-Pleszczynski, S. Massé, et al. 1983;30(1):195-210. PubMed · Publisher

Abstract

In order to study the cellular and biochemical changes in early asbestosis, three groups of sheep were repeatedly exposed to intratracheal instillations of either saline (controls), low doses of UICC chrysotile asbestos (LD), or high doses of the fibers (HD) until an alveolitis was observed in all HD sheep during the twelfth month of exposure. All sheep were studied bimonthly by transbronchial lung biopsy (LB), bronchoalveolar lavage (BAL), pulmonary function tests (PFT), and chest roentgenograms (CXR). While LBs of the HD sheep demonstrated large accumulations of monocyte-macrophages in the alveolar and interstitial spaces, those of controls and LD sheep did not. In BAL, there was no difference in total and differential cell counts between groups, but the BAL lymphocyte proliferative capacity was clearly depressed in all asbestos-exposed sheep. In the BAL supernatant, total proteins (mainly albumin, beta + gamma globulins) and lactate dehydrogenase were significantly elevated in the HD group only. This alveolitis was associated with a fall in vital capacity, lung compliance, diffusing capacity, and arterial PO2. Abnormalities on CXR appeared 3 months later. Thus, the cellular and biochemical features of early asbestosis are clearly distinct from those reported in idiopathic pulmonary fibrosis.
Characterization of three types of chrysotile asbestos after aerosolization. K.E. Pinkerton, A.R. Brody, D.A. McLaurin, et al. 1983;31(1):32-53. PubMed · Publisher

Abstract

Jeffrey Mine and Coalinga Mine chrysotile, two asbestos samples prepared for experimental research by the National Institute of Environmental Health Sciences, and the UICC B chrysotile reference sample have been characterized in the aerosolized state using gravimetric measurements, light microscopy, scanning electron microscopy, and x-ray energy spectrometry. These methods revealed (1) a greater "respirable" mass fraction in the Jeffrey and UICC B preparations compared to the Coalinga sample, (2) for fibers greater than 5 microns in length and less than 3 microns in diameter, Jeffrey Mine chrysotile contained a significantly greater fraction of fibers longer than 40 microns in length compared to the UICC B or Coalinga Mine chrysotiles, and (3) Jeffrey and UICC B chrysotile contained no fibers or fiber clusters which exceeded 2 microns in diameter while Coalinga chrysotile contained numerous fibers and fiber clusters which were greater than 2 microns in diameter. The characterization of these chrysotile preparations in the aerosolized state, in particular the Coalinga Mine chrysotile, demonstrated different fiber length and fiber width distributions when compared with previous characterizations of samples that had been dispersed in a liquid medium by ultrasonification. These observations emphasize the importance of determining size distribution of fibers in the aerosolized state for inhalation studies and the size distribution of fibers in a liquid suspension for oral ingestion, instillation, or injection studies. Because of differences in length-width distributions, each of the studied chrysotile preparations would be expected to have different patterns of deposition in the alveolar regions of the lung after an inhalation exposure.
Circulating immune complexes and antiglobulins (IgG and IgM) in asbestos-induced lung fibrosis. A. Lange, L.J. Nineham, D. Garncarek, et al. 1983;31(2):287-95. PubMed · Publisher

Abstract

Thirty-nine asbestos workers were examined with respect to the presence of IgG and IgM antiglobulins and circulating immune complexes. The overall incidence of raised levels of IgM antiglobulins and immune complexes was 63 and 28%, respectively. In the group positive for immune complexes, IgM antiglobulins were found more frequently than in those asbestos workers lacking immune complexes. However, all cases with the highest levels of IgM antiglobulins had normal or only slightly elevated levels of immune complexes. IgG antiglobulin levels were not elevated in asbestos workers. Asbestos workers with IgG antinuclear antibodies had the highest incidence of elevated levels of immune complexes.
Cytotoxicity of a short-fiber chrysotile asbestos for human alveolar macrophages: preliminary observations. H. Yeager, D.A. Russo, M. Yañez, et al. 1983;30(1):224-32. PubMed · Publisher

Abstract

Studies were performed to compare the cytotoxicity for human alveolar macrophages of a naturally occurring short-fiber chrysotile asbestos (RG 144) to that of a standard reference mixed-fiber (long and short) chrysotile asbestos (UICC chrysotile A. Rhodesian). Parallel studies were also performed with quartz (Min-U-Sil 15), a known macrophage toxin. On a mass basis, and after 24 hr incubation, RG 144 was more cytotoxic than the UICC standard reference fiber and less toxic than quartz (silica). The cytotoxic potential of RG 144 chrysotile was further enhanced after size reduction by milling. These findings may have important biologic implications with respect to the use of short-fiber asbestos in industry.
Effect of chrysotile and crocidolite on the morphology and growth of rat pleural mesothelial cells. M.C. Jaurand, I. Bastie-Sigeac, J. Bignon, et al. 1983;30(2):255-69. PubMed · Publisher

Abstract

The effects of the UICC asbestos fibers chrysotile A and crocidolite on the morphology and growth of rat pleural mesothelial cells were examined. The response was different according to the fiber used. Within 4 hr of treatment with 5, 10, 20, or 50 micrograms/ml of chrysotile fibers, cell morphology showed intense vacuolization, in both logarithmic and confluent cells. Following treatment of growing cells with 20 or 50 micrograms/ml of chrysotile fibers, cell spreading was also observed. Four hours after treatment of cells with 5, 10, or 20 micrograms/ml of crocidolite fibers, no such changes were seen. Vacuolization appeared later and was much less marked than for chrysotile fibers. The mesothelial cell population-doubling time of about 30 hr was not significantly altered by addition of 5 to 20 micrograms/ml of crocidolite fibers, but a concentration of 50 micrograms/ml lengthened doubling time to about 90 hr. Treatment with 5 or 10 micrograms/ml chrysotile fibers usually prolonged this time, but 20 or 50 micrograms/ml caused cell lysis. After 48 hr of incubation with both types of fiber, the proportion of mitosis was the same as in control cultures, whatever the fiber concentration, and asbestos fibers were often seen inside dividing cells.
Enhancement of benzo[a]pyrene mutagenicity by chrysotile asbestos in rat liver epithelial cells. B. Reiss, C. Tong, S. Telang, et al. 1983;31(1):100-4. PubMed · Publisher

Abstract

The co-mutagenicity of chrysotile asbestos and benzo[a]pyrene (B(a)P) was studied in adult rat liver (ARL-18) epithelial cells. Exposure to chrysotile alone did not increase the mutant incidence whereas B(a)P was mutagenic. Simultaneous exposure of the cells to chrysotile and B(a)P resulted in an enhanced mutant recovery compared to exposure to either of these substances alone. However, chrysotile did not enhance the mutagenicity of the carcinogen, N-methyl-N'-nitro-N-nitrosoguanidine.
Mesothelioma in pet dogs associated with exposure of their owners to asbestos. L.T. Glickman, L.M. Domanski, T.G. Maguire, et al. 1983;32(2):305-13. PubMed · Publisher

Abstract

Pet dogs with spontaneous mesothelioma were used to identify environmental exposures that might increase their owner's risk of asbestos-related disease. These animals share man's domicile environment, yet do not indulge in activities (e.g., smoking, working) which confound interpretation of epidemiologic studies. Eighteen histologically confirmed canine mesotheliomas were diagnosed at the Veterinary Hospital of the University of Pennsylvania, Philadelphia, from April 1977 to December 1981. Sixteen owners of cases and 32 owners of age, breed, and sex-matched controls were interviewed to determine their occupation and medical history and their dog's medical history, life style, diet, and exposure to asbestos. An asbestos-related occupation or hobby of a household member and use of flea repellents on the dog were significantly associated with mesothelioma. In addition, there was a trend indicating an increased risk of mesothelioma with an urban residence. Lung tissue from three dogs with mesothelioma and one dog with squamous cell carcinoma of the lung had higher levels of chrysotile asbestos fibers than lung tissue from control dogs. These findings indicate that well-designed epidemiological studies of spontaneous tumors in pet animals may provide insight into the role of environmental factors in human cancers and serve as a valuable sentinel model to identify environmental health hazards for humans.
Mount St. Helens' volcanic ash: hemolytic activity. V. Vallyathan, M.S. Mentnech, L.E. Stettler, et al. 1983;30(2):349-60. PubMed · Publisher

Abstract

Volcanic ash samples from four Mount St. Helens' volcanic eruptions were subjected to mineralogical, analytical, and hemolytic studies in order to evaluate their potential for cytotoxicity and fibrogenicity. Plagioclase minerals constituted the major component of the ash with free crystalline silica concentrations ranging from 1.5 to 7.2%. The in vitro hemolytic activity of the volcanic ash was compared to similar concentrations of cytotoxic and inert minerals. The ash was markedly hemolytic, exhibiting an activity similar to chrysotile asbestos, a known fibrogenic agent. The hemolysis of the different ash samples varied with particle size but not with crystalline silica concentration. The results of these studies taken in conjunction with the results of our animal studies indicate a fibrogenic potential of volcanic ash in heavily exposed humans.
Nonasbestos pulmonary mineral fibers in the general population. A. Churg. 1983;31(1):189-200. PubMed · Publisher

Abstract

Total pulmonary nonasbestos mineral content was determined for a series of 20 patients who had no occupational dust exposure. To extract mineral fibers, lung tissue was dissolved in bleach and the treated sediment transferred to the electron microscope grid. Mineral fibers were identified using electron diffraction and energy dispersive x-ray spectroscopy. The mean number of nonasbestos fibers, 106 X 10(3)/g wet lung, was almost identical to the mean number of asbestos fibers, 102 X 10(3)/g. Thirteen different species or groups of nonasbestos minerals were found: apatite accounted for 18% of the total and talc for 16%. All other forms accounted for less than 8% each. Silica was found in every lung, and talc in 19 of 20 lungs. Of the fibers, 86% were shorter than 5 microns, and most of the fibers had aspect ratios less than 15. No correlations were seen between numbers or types of fibers and age, sex, or smoking. It is concluded that (1) substantial numbers of nonasbestos fibers are present in lungs of the general population. Most of these fibers are short and of low aspect ratio; and (2) by phase microscopy one is as likely to observe nonasbestos as asbestos fibers in these preparations, indicating that light microscopic methods are not suitable for this type of analysis. These data provide a baseline for comparison with patients believed to have a mineral fiber-related disease.
Observations on the distribution of asbestos fibers in human lungs. A. Churg, P. Wood. 1983;31(2):374-80. PubMed · Publisher

Abstract

In an attempt to begin evaluating the distribution of mineral fibers within lung, multiple small adjacent samples were selected from peripheral portions of three normal and six asbestotic lungs, and analyzed for asbestos and nonasbestos fiber content. For both normal and fibrotic lungs there was marked variation in fiber concentration from site to site; the mean in-case ratio of maximum to minimum fiber concentration was 7.5 for amosite and crocidolite, 7.0 for tremolite, 3.8 for chrysotile, 4.0 for nonasbestos fibers, and 5.4 for asbestos bodies. In order to test the precision of the membrane filter method of quantitating particulates, multiple replicate samples of reference mineral standards were examined in a similar fashion; for these standard samples the ratio of maximum to minimum particle concentration varied from only 1.3 to 1.5. It is concluded that: (1) the membrane filter preparation technique used here for counting fibers provides reproducible results, and (2) there is marked variation in asbestos and nonasbestos fiber concentration from area to area within lung tissue. The latter finding implies that analysis of small subpleural lung biopsies may produce misleading results, and that larger pieces or several pieces should be analyzed when attempting to define total asbestos fiber content of the lung.
Quantitative assessment of chrysotile fibrils in the bloodstream of rats which have ingested the mineral under different dietary conditions. M. Weinzweig, R.J. Richards. 1983;31(2):245-55. PubMed · Publisher

Abstract

Samples of hepatic portal blood derived from control rats and from animals ingesting chrysotile asbestos were examined for the presence of mineral fibers. Only fibrils (97% less than 1 micron) were detected in the blood samples of both control and chrysotile-exposed rats. Total fibril counts per milliliter of blood revealed that in 6 out of 15 of the dietary experiments, the chrysotile-exposed groups had significantly higher counts than the equivalent controls. The actual quantity of chrysotile mineral (by counts or mass) which may be persorbed upon passage through the gastrointestinal tract and enter the blood stream is minute in comparison with the ingested dose.
The effects of chrysotile and crocidolite asbestos on the lower respiratory tract: analysis of bronchoalveolar lavage constituents. E. Kagan, Y. Oghiso, D.P. Hartmann. 1983;32(2):382-97. PubMed · Publisher

Abstract

This study was designed to evaluate the effects of amphibole and serpentine asbestos inhalation on the constituents of the lower respiratory tract. Bronchoalveolar lavage (BAL) analyses were performed on three groups of rats: one group was exposed to chrysotile (serpentine) asbestos, another group was exposed to crocidolite amphibole asbestos, while a third group was sham-exposed. Intermittent inhalational exposures lasted three months. The total BAL cell yields and the macrophage content of BAL cells were significantly lower after asbestos exposure, especially in the chrysotile-exposed group. These effects persisted for as long as 1 year after the cessation of exposure. Multinucleated macrophages were seen in BAL cells from both asbestos-exposed groups. Striking ultrastructural alterations of macrophage morphology were noted in BAL cells from both groups of asbestos-exposed rats. Chrysotile fibers were not seen in any BAL cells from chrysotile-exposed animals. However, 15 months after terminating the exposure regimen, a sizeable proportion of BAL macrophages from crocidolite-exposed rats contained phagocytosed asbestos fibers. Significantly higher beta-glucuronidase and lactate dehydrogenase activity was found in BAL fluids from both asbestos-exposed groups and was detected 17-18 months after exposure had ceased. These observations have served as useful correlates of asbestos-mediated injury to the lower respiratory tract. They have also provided evidence of continual pathological sequelae occurring long after withdrawal from asbestos exposure.
The hemolytic activity of chrysotile asbestos fibers: a freeze-fracture study. J.P. Pelé, J. Dunnigan, R. Calvert. 1983;31(1):152-63. PubMed · Publisher

Abstract

Short asbestos fibers isolated by a sedimentation procedure have a strong hemolytic activity. In the presence of ferritin particles, hemolysis by chrysotile fibers is inhibited at least during the first 10 min. Freeze-fracture studies show that after 20 sec or 2 min of contact between the fibers and the RBC membrane, the intramembranous particles remain randomly distributed over the whole surface of the P-face. On the E-face of the asbestos-treated red blood cell membranes, the number of intramembranous particles is significantly reduced. With the transmission electron microscopy, it is not possible to resolve the trilaminar structure of the ghost membrane around the deeply buried asbestos fibers. It is postulated that the membrane defects brought about by asbestos are caused by the adsorption of one membrane constituent, possibly phospholipids, on the chrysotile fibers.
Translocation of inhaled dust to the pleura. P.F. Holt. 1983;31(1):212-20. PubMed · Publisher

Abstract

Inhaled chrysotile asbestos or carbon dust that reaches the alveoli in guinea pig lungs is ingested by macrophages which move through the parenchyma of the lung toward the pleura. Some macrophages are eliminated from the lung by passing through blood vessel or bronchiolar walls. Those that reach the pleura are mainly aggregated in a few small areas. They may pass through the pleura. The active macrophages stain blue with Perls' reagent due to iron in the lysosomes. Occasionally, a macrophage may disintegrate while passing through the pleura and Perls-positive lysosomes become distributed over an area, presumably in the lymphatics.
Wollastonite exposure and lung fibrosis. M.S. Huuskonen, A. Tossavainen, H. Koskinen, et al. 1983;30(2):291-304. PubMed · Publisher

Abstract

Wollastonite is a naturally occurring acicular or fibrous metasilicate used in ceramics and as a substitute for asbestos in some applications. Wollastonite fibers are rather similar in form, length, and diameter to amphibole asbestos fibers but mineralogically they are different. Dust measurements in both the Finnish limestone--wollastonite quarry and in the flotation plant yielded high concentrations of both total dust and respirable fibers in some operational stages. The clinical study comprised a total of 46 men who had been exposed to wollastonite at the quarry for at least 10 years. Three of the fifteen nonsmokers showed chronic bronchitis. Radiographs revealed slight lung fibrosis among fourteen men, and slight bilateral pleural thickening among thirteen men. Their sputum specimens were normal. Spirometry and nitrogen single breath tests indicated the possibility of small airways disease.
Absence of mutagenic activity of three forms of asbestos in liver epithelial cells. B. Reiss, S. Solomon, C. Tong, et al. 1982;27(2):389-97. PubMed · Publisher

Abstract

The amosite, crocidolite, and chrysotile forms of UICC asbestos were assayed for their ability to induce gene mutations at the hypoxanthine-guanine phosphoribosyl transferase locus. Using adult rat liver-derived (ARL-6 and ARL-18) cells in culture, no consistent or significant increase occurred in the number of mutants resistant to the purine analog, 6-thioguanine, after exposure to toxic levels of amosite, crocidolite, or chrysotile. These results support the concept that asbestos is an epigenetic carcinogen that does not alter DNA.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Analysis of cores of ferruginous bodies from former asbestos workers. R.F. Dodson, M.F. O'Sullivan, M.G. Williams, et al. 1982;28(1):171-8. PubMed · Publisher
Asbestos brake emissions. R.L. Williams, J.L. Muhlbaier. 1982;29(1):70-82. PubMed · Publisher

Abstract

An enclosed brake-testing machine was built to determine the importance of asbestos emissions from automobile brakes. Higher emissions resulted from disc brakes than from drum brakes due to the smaller surface area contacting the wheel in the former case. Median emissions from one disc brake were 3.3 mg particulate/stop (55% airborne. 12% sedimentary, 34% brake-entrained), 0.6 mg C/stop as hydrocarbons, 0.7 mg C/stop as CO2, and 0.1 mg C/stop as CO. Higher emissions were observed with increases in velocity and deceleration rate. The mass median aerodynamic diameter of the emitted particles was 3.1 µm. Although the original brake material was about 50% asbestos, the emitted particles averaged only 0.029% asbestos. Therefore, it appears that over 99.9% of the mass of original asbestos fibers was broken down into nonfibrous magnesium silicates. In addition, asbestos fibers which are on the order of millimeters in length in the brake had a median length of 0.5 µm in the emitted debris. Based on the mass emission results and a stopping rate of 1.2 stops/km, it can be estimated that 2.6 µg of asbestos/km/vehicle is emitted into the air, 0.76 µg/km settles to the roadway, and 2.2 µg/km is entrained in the wheel. Although brake emissions are responsible for a minor fraction of ambient asbestos levels, there may be a noticeable increase in asbestos levels near high-braking areas such as tollbooths.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Characteristics of peritoneal macrophages induced by asbestos injection. K. Donaldson, J.M. Davis, K. James. 1982;29(2):414-24. PubMed · Publisher

Abstract

The effect of single intraperitoneal injections of UICC crocidolite, UICC chrysotile, and a latex control particulate on the induced murine peritoneal macrophage population was measured. Spreading, Fc receptor avidity, and phagocytosis were measured 3, 18, and 70 days after injection. When activation of the induced macrophage populations was found at all three times with asbestos, but not with latex, experiments were undertaken to determine whether the asbestos-activated macrophages had attained the full tumoricidally activated state. An in vitro assay measuring macrophage cytotoxicity to tumor cells revealed that the tumoricidal potential of asbestos-activated macrophages was low at 3 and 5 days and negligible by 35 days after injection. An in vivo assay measuring the effect of asbestos on tumor growth generally supported the contention that asbestos-activated macrophages were not tumoricidal, although one dose of UICC chrysotile did produce a small, significant reduction in growth of a concomitant tumor. It was concluded that a single intraperitoneal asbestos injection in mice induces activated macrophages which do not become fully tumoricidal.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Comparative effects of fibrous and nonfibrous minerals on cells and liposomes. C.D. Woodworth, B.T. Mossman, J.E. Craighead. 1982;27(1):190-205. PubMed · Publisher

Abstract

The comparative effects of chrysotile asbestos, silica, talc, kaolinite, and montmorillonite on cellular and artificial membranes were examined using three test systems-monolayer cultures of tracheal epithelial cells, suspensions of sheep erythrocytes (RBC), and preparations of phospholipid-cholesterol vesicles. The four minerals caused perturbations in each system, although to varying degrees. Membrane alterations induced by chrysotile asbestos and the clay mineral montmorillonite were more striking than those caused by other dusts. The results obtained with the three test systems were consistent. Electron microscopic observations indicated that the particles were phagocytized by cultured epithelial cells of hamster tracheal origin and developed intimate associations with the RBC plasma membrane. These interactions are discussed with regard to possible mechanisms of cellular injury and their relevance to pulmonary disease.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Experimentally induced mesothelioma in white rats in response to intraperitoneal administration of amorphous crocidolite asbestos: preliminary report. K. Kolev. 1982;29(1):123-33. PubMed · Publisher

Abstract

The experiment was performed on white rats that were administered intraperitoneally two types of crocidolite asbestos-fibrous and amorphous. The fibrous structure, with fiber length ranging between 3 and 5 µm, and the amorphous state of the second type were proved by electron microscopy and infrared spectrophotometry. In the group treated with amorphous asbestos, at an average interval of 484 days after the administration, eight cases of mesothelioma were observed, while in the group treated with fibrous asbestos only three cases of mesothelioma were found, i.e., the results obtained show a statistically significant difference. The fibrous structure of asbestos as the predominant cause of peritoneal mesothelioma induction is questioned and a new explanation of the fact that amorphous asbestos induces approximately three times as many cases of mesothelioma than fibrous asbestos is considered.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Identification of carcinogens by measurement of cell-mediated immunity. III. Immunity to asbestos-induced rat peritoneal mesothelioma. D.A. Cole, R.H. Stevens, L.A. Will. 1982;28(1):77-83. PubMed · Publisher

Abstract

Antitumor cell-mediated immune (CMI) responses were detected in rats with asbestos (Canadian chrysotile B)-induced peritoneal mesotheliomas. The CMI was determined by in vitro lymphoid-cell cytotoxicity expressed by committed peripheral blood lymphoid cells (PBLC) obtained from the tumor-bearing animals toward cultured target cells of the tumors. Two apparently different target cell cultures which were developed from tumors of the same rat, one with epitheliod and the other with fibroblastic morphology, were lysed to the same degree by the sensitized PBLC. Specificity was observed for the PBLC reactivity as no cytotoxicity was expressed toward target cells derived from tumors of either ectodermal or entodermal origin. Nor were PBLC obtained from rats bearing tumors of these two tissue types capable of expressing injury to the mesothelioma target cells. These findings indicate that immune responsiveness developed to mesothelioma and suggest that such measurements might be useful for detecting environmental exposures to asbestos fibers.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Identification of carcinogens by measurements of cell-mediated immunity. II. Assay specificity. R.H. Stevens, D.A. Cole. 1982;28(1):67-76. PubMed · Publisher

Abstract

Studies utilizing the Fischer F334 inbred rat model were undertaken to define the specificity for antitumor cell-mediated immune (CMI) measurements as determined by lymphoid-cell cytotoxicity to determine whether such values could serve as an analytical reflection for the carcinogenic potential of environmental pollutants. The investigations revealed that specificity was apparently limited to a carcinogenic insult and designated by the embryonic origin of the affected tissue. For example, it was found that animals having X-ray-induced small-bowel, 1,2-dimethylhydrazine-induced colon, and 7,12-dimethylbenz[a]anthrazene-induced pancreas adenocarcinomas possessed lymphoid cells cytotoxic to tumor target cells of either the small bowel or pancreas, but were not lytic to tumor tissue of ectoderma or mesodermal origin. Nor was injury inflicted upon normal intestinal, kidney, or tail fibroblastic cells, while significant lysis was seen when normal fetal cells were used as targets. The findings also suggest that the presence of the carcinogen in the assay has little influence upon the CMI values. Thus, the present investigation continues to support the concept that immunological responsiveness may serve as a useful measure for specifically identifying and quantitating effects of environmental carcinogens.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Influence of the sialic acid content of the membrane on its susceptibility to chrysotile. J. Depasse. 1982;27(2):384-8. PubMed · Publisher

Abstract

Sialic acid removal from human erythrocytes does not influence their susceptibility to chrysotile. This is in contradiction with the view that hemolysis by chrysotile is related to the clustering of membrane sialoproteins by the mineral. Sialic acid removal from horse erythrocytes slightly decreases their sensitivity toward chrysotile. As horse, but not human, erythrocytes contain lipid-bound sialic acid, it supports the proposal that interactions between chrysotile and the lipidic part of the membrane are responsible for the hemolytic activity of that mineral.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Malignant alpha chain disease and exposure to asbestos. D. Rouhier, C. André, C. Allard, et al. 1982;27(1):222-5. Case report PubMed · Publisher
The pathological effects of prolonged asbestos ingestion in rats. R.E. Bolton, J.M. Davis, D. Lamb. 1982;29(1):134-50. PubMed · Publisher

Abstract

The effects of prolonged ingestion of amosite, crocidolite, and chrysotile UICC standard reference asbestos samples were examined in groups of laboratory rats. Animals were given over 250 mg per week for periods up to 25 months and were monitored for the remainder of their life span. Animals were examined for evidence of pathological effects and gastrointestinal mucosal cytokinetic disturbances and for signs of penetration and dissemination of fiber. There was no excess of malignant tumors in the experimental groups when compared with control animals, and no gastrointestinal mucosal abnormalities were found. An examination of the cytokinetic status of a subgroup of animals exposed to asbestos similarly showed no evidence of any adverse effects of prolonged ingestion of amosite asbestos fiber. Detailed electron microscopic examination of various tissue residues for the presence of asbestos fibers was also undertaken. No penetration and/or damage to any of the gut tissues was found. Although occasional fibers were found in a variety of tissue residues, there was no evidence of preferential retention of fibers within any specific tissue and no sign of higher fiber burdens in those animals with tumors. It was concluded that there were no significant adverse effects of prolonged asbestos ingestion in healthy laboratory rats. The implications of these findings are discussed in the light of other published work.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Thymidine incorporation by lung fibroblasts as a sensitive assay for biological activity of asbestos. I. Lemaire, D. Gingras, S. Lemaire. 1982;28(2):399-409. PubMed · Publisher

Abstract

Fibroblasts exposed to chrysotile B asbestos displayed an initial growth inhibition compared to controls during the first 24 hr of incubation. At 48 hr, however, there was resumption of cell proliferation as evidenced by elevated thymidine (TdR3H) incorporation. UICC samples of chrysotile A, chrysotile B, crocidolite, amosite, and anthophyllite all altered thymidine incorporation by lung fibroblasts in a dose-dependent manner and to different maximal levels. Amphibole asbestos was either equally or less active than chrysotile. Silica had the lowest activity. Various other particles, including latex, zymosan, titanium dioxide, magnetite, and Mt. St. Helens volcanic ash, had no effect. Chemically modified chrysotile samples which retained their fibrous structure were also tested for possible alterations of fibroblast thymidine incorporation. The DNA synthesis response of human lung fibroblasts to asbestos correlates with its in vivo fibrogenic and tumorigenic potential and may prove useful in determining the pathological effects of asbestos.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Translocation of asbestos dust through the bronchiolar wall. P.F. Holt. 1982;27(2):255-60. PubMed · Publisher

Abstract

Inhaled chrysotile asbestos fibers that settle on the epithelium of the larger bronchioles are removed from the lung by cilia. Fibers that reach the pulmonary alveoli may be phagocytized by macrophages which move toward the periphery of the lung by passing through alveolar walls. Some of these cells aggregate in alveoli near larger bronchioles and may then penetrate the bronchiolar wall. They are shed in the bronchiolar lumen, where they are elevated by cilia to the trachea. Elimination of chrysotile from alveoli depends on macrophages; fibers persist if there are insufficient macrophages.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Analyses of tissue, blood, and urine samples from a baboon gavaged with chrysotile and crocidolite asbestos. W.H. Hallenbeck, D.R. Markey, D.G. Dolan. 1981;25(2):349-60. PubMed · Publisher

Abstract

Tissue, blood, and urine samples from one test and one control baboon were analyzed by transmission electron microscopy for the presence of chrysotile and crocidolite asbestos. The test animal had been gavaged with cumulative doses of 800 mg each of chrysotile and crocidolite asbestos. Urine and blood samples were collected during the 15-day gavage and 21-day postgavage period. Twenty-two tissues were collected at sacrifice. None of the analyses of tissue, blood, or urine samples from the test animal exceeded the expected level of background contamination for chrysotile. One crocidolite bundle was observed in a test sample. The results of this study indicate that asbestos fibers do not penetrate the gastrointestinal tract of the baboon and migrate to various tissues.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Biological reactivity of calcium silicate composites--in vitro studies. J. Hunt, F.D. Pooley, R.J. Richards. 1981;26(1):51-68. PubMed · Publisher

Abstract

The biological reactivity of three samples of manmade calcium silicate composites (A-C) was compared with chrysotile asbestos and titanium dioxide in simple in vitro test systems. Like chrysotile, composite A was actively hemolytic and its hemolytic potential was increased upon sonication. Heat treatment, coincidental with color changes, produced alterations in their hemolytic potential. All the composites were equally active in reducing alveolar macrophage viability and, like chrysotile, calcium silicate B interfered with collagen deposition in lung fibroblast cultures. Composite A produced little effect on fibroblast cultures except at high doses. The composites were all less reactive than chrysotile but more reactive than titanium dioxide. The order of reactivity of each individual composite was different in the test systems employed which may be related in part to their different physical nature but also to their different surface chemistry.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Cancer morbidity investigations: lessons from the Duluth study of possible effects of asbestos in drinking water. E.E. Sigurdson, B.S. Levy, J. Mandel, et al. 1981;25(1):50-61. PubMed · Publisher
Coagulation of human plasma by asbestos fibers. J.A. Hamilton, J.Y. Chan, H.Z. Movat. 1981;26(1):119-24. PubMed · Publisher

Abstract

Negatively and positively charged asbestos fibers shorten the partial thromboplastin time of human plasma, indicating coagulation of the plasma. A sample containing short (<5 µm in length) chrysotile fibers is ineffective. Only the negatively charged amphiboles (crocidolite and amosite) are able to activate factor XII (Hageman factor). This particular effect of the amphiboles is enhanced by high-molecular-weight kininogen and leads to kinin formation.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Comparative pulmonary responses to inhaled inorganic fibers with asbestos and fiberglass. K.P. Lee, C.E. Barras, F.D. Griffith, et al. 1981;24(1):167-91. PubMed · Publisher

Abstract

One group of rats, hamsters, and guinea pigs was exposed to amosite asbestos by inhalation of fibers of lengths greater than 5 µm at 3.1 x 10^6/liter, fiberglass at 0.7 x 10^6/liter, potassium octatitanate (Fybex, Du Pont's registered trademark for inorganic reinforcing titanate fibers) at 2.9 x 10^6/liter, and pigmentary potassium titanate (PKT) at 2.0 x 10^6/liter, respectively, for 6 hr/day for 3 months. One group of animals exposed to air alone was used as control. In addition, three groups of rats, hamsters, and guinea pigs were exposed to Fybex at 2.9 x 10^6/liter, 13.5 x 10^6/liter, and 41.8 x 10^6/liter, respectively, for 3 months. One group served as control. Asbestos, Fybex, and PKT produced essentially similar pulmonary responses but with marked differences in fibrogenicity and species differences. Asbestos was the most potent fibrogenic agent and was more than 10 times more fibrogenic than Fybex in terms of exposure concentration. Dose-related fibrogenic activity was found in the animals exposed to Fybex. PKT was the least fibrogenic and produced very minute pulmonary fibrosis in rats and hamsters but not in guinea pigs. Fine fiberglass particles were not fibrogenic. Rats revealed more fibrogenic pulmonary reactions than guinea pigs or hamsters. A few pulmonary tumors developed in animals exposed to asbestos, Fybex, and fiberglass, but their numbers were too small to allow any conclusions on carcinogenicity to be drawn. Fybex produced mesotheliomas in a few hamsters and its possible carcinogenic potential cannot be ruled out.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Early lung events following low-dose asbestos exposure. R. Bégin, M. Rola-Pleszczynski, P. Sirois, et al. 1981;26(2):392-401. PubMed · Publisher

Abstract

A conscious sheep model recently developed to study sequentially the bronchoalveolar milieu was applied to the investigation of the early lung events following very low dose asbestos exposure. UICC Canadian chrysotile fibers were administered in three monthly intratracheal injections of a suspension of 0 (controls), 1,2,4, 8, and 16 mg of asbestos in 50 ml saline. Three sheep per dose were repeatedly exposed to the same monthly doses and all were studied by serial pulmonary function (PF) tests, transbronchial lung biopsies (LB), and bronchoalveolar lavages (BAL). These low-dose exposures did not change the PF tests; routine lung histopathology was not altered except for the observation of occasional fibers in the alveoli, but there was a significantly higher yield in the total BAL cellular due to a marked increase in the macrophage and a small rise in the lymphocyte populations. These changes in the BAL cells occurred without significant changes in the biochemical analyses of the BAL supernatant. These data establish that very low dose asbestos exposure induces migration of macrophages and lymphocytes into the bronchoalveolar milieu. These cells have a major role in the lung defense and have been implicated in the development of asbestos-related diseases.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Magnetic lung measurements of relation to occupational exposure in asbestos miners and millers of Quebec. D. Cohen, T.S. Crowther, G.W. Gibbs, et al. 1981;26(2):535-50. PubMed · Publisher

Abstract

Fe,O, particles (ferrimagnetic) are usually attached to asbestos fibers (nonferrimagnetic) in the chrysotile asbestos mining and milling industries; therefore, a magnetic measurement of Fe,O, in the lungs of workers in these industries could help determine the amount of asbestos which has been inhaled and retained in their lungs. As a first assessment of this method, magnetic measurements were made of Fe,O, in the lungs of 115 miners and millers in Quebec. These measurements at an industrial site were found to be feasible and practical; however, the amount of Fe,O, seen in the lungs of those with welding exposure was large enough to mask the Fe3O4 contributed by asbestos, and this subgroup was considered separately. For the remainder (nonwelders), the amount of Fe,O, was plotted against a total dust exposure index (asbestos and other dust) estimated for each worker. Although the correlation between these quantities was not high, it was statistically significant at the 1% level. Because retained asbestos is likely to increase with increasing exposure to total dust, this correlation suggests that a magnetic lung measurement of a chrysotile miner or a miller does reflect, to some extent, the amount of asbestos in his lung. There was considerable scatter in the data, partly due to individual variations in deposition and clearance, to which this method is sensitive. When the data of only the nonsmokers were plotted, the amount of Fe,O, was greater than for the total group of nonwelders. This is consistent with previous findings that less dust is deeply deposited in the lungs of smokers, due to constriction of small airways.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Manifestations of cellular immunity in the rat after prolonged asbestos inhalation. II. Alveolar macrophage-induced splenic lymphocyte proliferation. K. Miller, E. Kagan. 1981;26(1):182-94. PubMed · Publisher

Abstract

The present study has shown that alveolar macrophages from asbestos-exposed rats (dusted macrophages) can induce the proliferation of autologous splenic lymphocytes (dusted lymphocytes) as well as the proliferation of syngeneic lymphocytes from control nonexposed rats (control lymphocytes). Significant lymphoproliferation did not occur when alveolar macrophages from control rats (control macrophages) were cocultured with control or dusted splenic lymphocytes for similar periods of time (72 or 96 hr). The activation of control lymphocytes by dusted macrophages was similar, in some respects, to the lymphoproliferative response evoked by sodium periodate-treated control macrophages, since both these reactions peaked at 72 hr and were abolished by treatment of the macrophages with the reducing agent, L-cysteine. This periodate-like response produced by dusted macrophages appears to result from aldehyde-like modifications on the macrophage cell membrane. L-Cysteine treatment did not, however, affect the blastogenic response induced by dusted macrophages on dusted lymphocytes, which peaked at 96 hr. Since the in vitro addition of crocidolite to cell cultures did not trigger lymphoproliferation, these collective findings suggest the expression of asbestos-related antigen-like determinants on the surface of dusted macrophages. We conclude that the proliferative reactions induced in splenic lymphocytes by dusted macrophages were a consequence of two different phenomena: a periodate-like effect (noted in control lymphocytes) and an effect produced by a putative asbestos-related, macrophage-associated antigen (observed in dusted lymphocytes).

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Mechanisms of asbestos carcinogenesis. B.T. Mossman, J.E. Craighead. 1981;25(2):269-80. Review PubMed · Publisher
Methodological problems in ecologic studies of the asbestos--cancer relationship. S. Graham. 1981;25(1):35-49. PubMed · Publisher
The biological reactivity of calcium silicate composites: in vivo studies. R.J. Richards, T.D. Tetley, J. Hunt. 1981;26(2):243-57. PubMed · Publisher

Abstract

The biological reactivity of three respirable samples of calcium silicate composites was compared with that of chrysotile and titanium dioxide 1 and 4 weeks after intratracheal instillation of different doses of the minerals into rat lungs. The parameters chosen for investigation were numerical, cytological, and biochemical (RNA, DNA, and hydrolytic enzyme activities) alterations induced in the free cells, biochemical changes in the remaining lavaged lung tissue, and the amount of the lipoprotein-rich fraction (pulmonary surfactant) lavaged from the alveolar surface. Differential, dose-dependent (by mass) effects were produced by the composites which were all more reactive than titanium dioxide initially (1 week) although after clearance (4 weeks) many of the induced alterations produced by two composites were practically reversible. The relationship between the reactivity of the calcium silicates in simple in vitro model systems with their activity in vivo is discussed.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Adsorption isotherms of albumin and ferritin on Rhodesian chrysotile: effects of magnesium depletion. F. Valerio, M. Veggi, L. Santi. 1980;21(1):186-9. PubMed · Publisher
An epidemiological survey of immunological abnormalities in asbestos workers. I. Nonorgan and organ-specific autoantibodies. A. Lange. 1980;22(1):162-75. PubMed · Publisher

Abstract

Antinuclear antibodies (ANA) in asbestos workers are significantly correlated with the symptoms of lung fibrosis. The incidence of ANA in asbestosis is not sex dependent. In nonasbestotic asbestos workers ANA are more frequently seen in females rather than in males. ANA, in asbestos workers, belong more frequently to the IgG class and these autoantibodies are found in higher titers in asbestos workers as opposed to the controls. On a group basis DNA antibodies are not significantly elevated in asbestosis. Rheumatoid factor (RF) was found with the highest frequency in male asbestotic cases. However, RF and/or smooth muscle antibody (SMA) positive cases are significantly clustered among workers with chronic sinusitis and chronic bronchitis. Non-organ-specific autoantibodies were found more frequently in those with a vital capacity impairment as opposed to asbestos workers normal in this respect. Organ-specific autoantibodies are rarely seen in asbestos workers. Moreover, except for sheep red blood cell (SRBC) antibodies in women, no correlation was found among some natural and influenza antibodies and non-organ-specific autoantibodies in asbestos workers.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
An epidemiological survey of immunological abnormalities in asbestos workers. II. Serum immunoglobulin levels. A. Lange. 1980;22(1):176-83. PubMed · Publisher

Abstract

A significant elevation of serum IgA and IgG was found in female asbestos workers below age 36. Higher values of serum IgA, IgG, and IgM were found in male asbestos workers over age 35, when compared to matched controls. Female asbestos workers, over age 35, statistically differ from their controls only with respect to IgG levels. Patients, with asbestosis and with an impairment of blood oxygen saturation, contribute greatly to the elevation of serum immunoglobulin levels in asbestos workers. The asbestosis process, but not chronic bronchitis, is responsible for high serum IgA and IgG levels.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Asbestos distribution in the Central Serpentine District of Maryland-Pennsylvania. J.H. Puffer, M. Germine, D.O. Hurtubise, et al. 1980;23(2):233-46. PubMed · Publisher
Characterizing and discriminating the shape of asbestos particles. H.G. Siegrist, A.G. Wylie. 1980;23(2):348-61. PubMed · Publisher

Abstract

The lengths and widths of approximately 1000 particles from each of four asbestos samples, two nonfibrous amphiboles, and one talc-serpentine sample were measured utilizing the SEM. The asbestos samples are commercially available and include chrysotile from Quebec, chrysotile from California, amosite from South Africa, and crocidolite from South Africa. The tremolite and talc-serpentine are from New York, and the riebeckite is from California. Beneficiation, including milling of amosite, crocidolite, and tremolite and air classifications of the two chrysotile samples, was done under commercial conditions; the riebeckite was milled in the laboratory. For comparison, the same measurements were made on the California chrysotile using TEM. Shape characterizations of the samples are compared using regression techniques. The usefulness of the various shape definitions including length, width, and aspect ratio (length/width) in characterizing and discriminating between samples is explored and evaluated. Significant results include: (i) Frequency distribution of log length, log width, and log aspect ratio show very apparent differences between asbestos and nonasbestos populations. (ii) Dimensional differences and accurate classification according to dimensions are enhanced by regressing log width and/or log aspect ratio against log length. (iii) Discriminant function analysis is able to quantify the distinction between asbestos and nonasbestos particle dimensions such that over 95% of the population assignments are correct. (iv) Log width is a more efficient classifier than log aspect ratio using either linear regression of discriminant function analysis for these particular samples. (v) The choice of instrumentation, i.e., TEM vs SEM, may affect the sample characterization. (vi) Quantitative descriptions of the dimensions of small particles may be related to the habit of the mineral and the structure of the mineral groups to which the particles belong. However, such mineralogical distinctions are probably not valid for particles whose longest dimension is less than about 1 µm.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Clearance of anthophyllite fibers from the rat lung and the formation of asbestos bodies. A. Holmes, A. Morgan. 1980;22(1):13-21. PubMed · Publisher

Abstract

The length distributions of both uncoated and coated fibers in the rat lung were measured at various times up to ? years following exposure to anthophyllite asbestos by inhalation. Fibers were measured by optical microscopy using a membrane filter technique which enables fibers with diameters down to about 0.2 μm to be detected. The frequency of uncoated fibers less than 5 μm in length decreased from 5% at 100 days after exposure to 19% after 2 years. These findings confirm and extend earlier investigations which showed that fibers in this length range are cleared more efficiently from the lung than longer fibers. The length distributions of uncoated and coated fibers were dissimilar. No coated fiber <10 μm in length was detected at any time and the greatest frequency invariably occurred in the 40- to 80-μm range. All fibers longer than 80 μm appeared to be coated. Although the appearance of coated fibers in the rat lung differs from those in human lung, there are similarities in the length distributions of uncoated and coated fibers.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Comparative toxicities of different forms of asbestos in a cell culture assay. B. Reiss, S. Solomon, J.H. Weisburger, et al. 1980;22(1):109-29. PubMed · Publisher

Abstract

Three forms of Union Internationale Contre le Cancer (UICC) asbestos, amosite, crocidolite, and chrysotile, were assayed for their cytotoxicity (inhibition of colony formation) in cell culture. Using embryonic human intestine-derived (I-407) and adult rat liver-derived (ARL-6) epithelial cells, the order of cytotoxicity was chrysotile > amosite > crocidolite. All three asbestos types were more toxic to I-407 than to ARL-6 cells. Chrysotile, amosite, and crocidolite were also tested for inhibition of colony formation in cultures of mouse colon-derived epithelial-like (MCE-1) cells; these cells were more resistant than the I-407 cells to all three fiber types; although similar to the ARL-6 cells in sensitivity to chrysotile and amosite, the MCE-1 cells were more sensitive to crocidolite then the ARL-6 cells. Leaching of the three asbestos forms for 3 days in sterile deionized water did not appreciably affect the cytotoxicity of I-407 or ARL-6 cells. Leaching in hydrochloric acid, however, greatly decreased the cytotoxicity of chrysotile on these cells and particularly in cultures of ARL-6 cells slightly increased the cytotoxicity of amosite and crocidolite. Leaching in deionized water altered the composition of the asbestos as revealed by release of substantial levels of Mg2+ and Ca2+ into the leaching fluid. Greater titers of these ions were released during leaching in hydrochloric acid.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Distribution of 6-6(n)-3[H]sucrose and its radiolabeled degradation products from isolated, perfused rat small intestine loops following prolonged ingestion of chrysotile asbestos. R. Jacobs, R.J. Richards. 1980;21(2):423-31. PubMed · Publisher
Dust elimination from pulmonary alveoli. P.F. Holt. 1980;23(1):224-7. PubMed · Publisher

Abstract

Some alveolar macrophages that engulf asbestos particles move through alveolar walls and spaces to the larger bronchioles. They pass through the bronchiolar wall to reach the lumen where they are elevated by cilia and pass out of the lung.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This single-author short communication described an animal experiment. Specific pathogen-free guinea pigs breathed dust from Rhodesian chrysotile asbestos for 24 hours, at about 1000 fibers longer than 1 micrometer per milliliter of air. They were killed at later times, including 20 weeks and about 40 weeks after exposure. Their lung sections were stained to mark macrophages, which are scavenger cells that swallow dust. The article does not say how many animals were used, and the findings were described, not counted. Macrophages carrying asbestos debris appeared in all sections, and some had fused into giant cells. Especially in animals killed about 40 weeks after exposure, a few macrophages seemed to be actively moving, some passing through alveolar walls. Macrophages were also seen in alveoli next to larger bronchioles, in the bronchiole walls and in the airway space. The author concluded that these cells apparently reach the larger airways by passing through alveolar and bronchiolar walls rather than along the airways. He suggested this may partly explain why dust leaves the alveoli slowly.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.
Identification of a particular amphibole asbestos fiber in tissues of persons exposed to a high oral intake of the mineral. R.E. Carter, W.F. Taylor. 1980;21(1):85-93. PubMed · Publisher

Abstract

Samples of liver, jejunum, and lung tissue from each of 32 persons with long-term, high-level oral exposure to a ferromagnesium silicate amphibole asbestos were ashed, and the residue was analyzed by means of transmission electron microscopy with selected area electron diffraction, and energy dispersive X-ray analytic techniques. Fibers of the type ingested were identified in the tissues of 29 of the 32 persons. Among ?I controls, the tissues of only 2 subjects contained this type of fiber-in each, a single fiber from a single tissue specimen. Chrysotile asbestos fibers were found in all tissues in most of the subjects studied.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
In vitro cytological and cytogenetic effects of an Indian variety of chrysotile asbestos. K.A. Babu, B.C. Lakkad, S.K. Nigam, et al. 1980;21(2):416-22. PubMed · Publisher

Abstract

The cytotoxic and cytogenetic effects of chrysotile asbestos (Indian Variety, AP-I) in vitro on Chinese hamster ovary cells were investigated. Chrysotile asbestos (AP-I) produces high vacuolization of cytoplasm, flattening of cells with increased size, and chromosomal aberrations. Both cytological and cytogenetic studies were dependent upon the dose and the period of exposure to chrysotile asbestos.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Particle size for differentiation between inhalation and injection pulmonary talcosis. J.L. Abraham, C. Brambilla. 1980;21(1):94-6. PubMed · Publisher
Primary pericardial mesothelioma following exposure to asbestos. E.I. Kahn, A. Rohl, E.W. Barrett, et al. 1980;23(2):270-81. PubMed · Publisher
Pulmonary function of control and industrially exposed Nigerians in asbestos, textile, and toluene diisocyanate-foam factories. U.G. Oleru. 1980;23(1):137-48. PubMed · Publisher

Abstract

The pulmonary function of 120 non-industrially exposed Nigerians and of workers in an asbestos-cement factory, a cotton textile factory, and a TDI-foam factory was investigated. The pulmonary function of the control subjects was significantly (P < 0.001) higher than that of any of the control subgroups. The total particulate levels in the factories corresponded to the level of dust-generating activity. The highest suspended particulate level in the asbestos-cement factory was 18.3 mg.m-3 while the highest level in the textile factory was 14.94 mg. rnm3. The highest total respirable fiber content in the asbestos-cement factory was 6.63 f.cm-3 and this occurred in the cement and asbestos mixing section. It seemed that the greatest risk to pulmonary function for the exposed subjects resulted from exposure to cotton dust, however, a probable acute exposure to toluene diisocyanate among a subgroup that had an exposure duration of about a year produced the highest depression of lung function observed among the exposed subjects. It seems that the pulmonary function of the Nigerian “normal” population has not changed in a decade, after an apparent increase in industrialization. The pulmonary function equations developed in this study showed good predictability and the FEV1 and FVC values calculated from these equations closely matched those calculated from equations developed for other African subjects.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Recovery of ingested asbestos fibers from the gastrointestinal lymph in rats. P. Sebastien, R. Masse, J. Bignon. 1980;22(1):201-16. PubMed · Publisher

Abstract

Using the transmission electron microscope, asbestos fibers have been assessed in lymph fluid collected from the thoracic lymph duct in five groups of rats previously exposed to asbestos fibers (by ingestion). Ten rats were gavaged a single dose weighing approximately 20 mg. Five were given pure UICC chrysotile A while another group of five had pure UICC crocidolite. All the rats of the chrysotile group were positive animals with recovery rate values ranging from 6.9 × 10^-7 to 3 × 10^-5 (90% of the fibers being recovered during the first 16 hr following the gavage). The crocidolite group had only three positive animals and lower recovery rate values of 5.7 × 10^-8 to 5.6 × 10^-7. A third group was fed a synthetic diet containing 1%, by weight, chrysotile with a majority of short fibers (90% below 4 µm). Of the 15 rats comprising this group, 13 were positive with maximum daily recovery rates ranging from 2.1 × 10^-7 to 2.1 × 10^-6. A group of eight rats fed the same kind of diet but containing a higher proportion of long fibers, showed only four positive animals, however, they had higher daily recovery rates ranging from 1.9 × 10^-5 to 2.1 × 10^-4. No fibers were encountered in the samples of the two control rats. This study demonstrates the passage of chrysotile and crocidolite fibers across the gastrointestinal wall, with the passage rate being higher for long fibers than short ones.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Stimulation of oxidant production in alveolar macrophages by pollutant and latex particles. G.E. Hatch, D.E. Gardner, D.B. Menzel. 1980;23(1):121-36. PubMed · Publisher

Abstract

Air pollutant dusts as well as chemically defined particles were examined for their activating effect on oxidant production (O2- and H2O2) in guinea pig alveolar macrophages (AM). Oxidant production was measured as chemiluminescence of albumin-bound luminol. All particles examined stimulated the AM in a dose-dependent manner to different maximal levels of oxidant production. Amphibole asbestos samples were the most active of all agents studied. Various immune reactants as well as silica, metal-oxide-coated fly ash, polymethyl methacrylate beads, and chrysotile asbestos had intermediate activity, while fugitive dusts, polybead carboxylate microspheres, glass and latex beads, uncoated fly ash, and fiberglass had the lowest activity. In addition to direct stimulatory action on AM, particles also lowered the subsequent responsiveness of the cells to the bacterial peptide stimulant, N-formylmethionyl phenylalanine. This effect was only partially due to the cytotoxicity of the particles. While some relationship appeared to exist between stimulatory activity and cytotoxicity of the particles, the exact role of O2- in mediating cytotoxic effects is still open to question. Oxidant production in AM is a parameter which may be important in determining the pathological effects of particles as well as of materials adsorbed to their surfaces.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
The activity of environmental samples in a cell culture test for asbestos toxicity. B. Reiss, J.R. Millette, G.M. Williams. 1980;22(2):315-21. PubMed · Publisher

Abstract

The inhibition of colony-forming efficiency of cultured human embryonic intestine-derived epithelial (I-407) cells was utilized in order to assay the toxic potential of six coded samples of particulate matter provided by the United States Environmental Protection Agency (EPA). The results of the assay indicated that the most toxic of the EPA samples tested “blindly” was amosite which was equal in toxicity to the amosite used, by chance, as a positive control. The toxicities of the particulates from drinking water were approximately 100-fold less than the amosite; of these, the order of toxicity of the samples was San Francisco > Seattle > Duluth. The samples of attapulgite clay and taconite tailings displayed approximately half the toxicity of the drinking water particulates. These results indicate that this assay provides a sensitive and accurate method for screening asbestos and asbestiform contamination for potential toxicity.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

1970s

Alterations in the surface-related phenomena of alveolar macrophages following inhalation of crocidolite asbestos and quartz dusts: an overview. K. Miller. 1979;20(1):162-82. PubMed · Publisher

Abstract

The possibility that immunological factors could be involved in the pathogenesis of asbestosis and silicosis was investigated. This study formed the basis of a Ph.D. Thesis. A brief discussion of the results obtained with particular reference to the differing effect of quartz and asbestos inhalation is presented. Rats were used as experimental animals and were exposed to the relevant dusts by inhalation to provide a model of the in vivo participation of the constituent mononuclear phagocytes. Early changes included alteration of surface morphology of the macrophages and an increased number of IgG receptor sites. In vivo membrane deposition of complement components on asbestos macrophages from crocidolite-dusted rats was demonstrated. When macrophages from crocidolite-dusted rats were cultured in vitro with splenic lymphocytes a prolonged physical interaction occurred followed by lymphocyte proliferation. The surface-related alterations leading to these phenomena were characterized. It is postulated that dusted macrophages participate in both cell-mediated and humoral interactions, and that host factors contribute to the development of dust diseases.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Cancer mortality in U.S. counties with shipyard industries during World War II. W.J. Blot, B.J. Stone, J.F. Fraumeni, et al. 1979;18(2):281-90. PubMed · Publisher

Abstract

Respiratory cancer mortality, 1950-1969, was consistently high in U.S. counties where shipyards were engaged in the construction and repair of large naval and cargo vessels during World War II. Over three-fourths of the shipyard counties had elevated rates (in comparison to rates in counties of similar population size in the same region of the country) for lung and laryngeal cancer among white males, with the excess particularly evident in the South. Mortality from lung cancer was high also among white females, and the rate of increase in both sexes was greater than recorded nationally. In addition, rates for oropharyngeal, esophageal, and gastric cancers tended to be elevated in the shipyard counties, but mortality from other tumors was roughly comparable to national levels. A causal relation to asbestos exposures in shipyards cannot be inferred from this correlational analysis, but the unusual mortality patterns underscore the need for broadly based analytic studies to evaluate the risk of cancer in persons with wartime shipyard employment.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Cyclic nucleotide concentrations in asbestos-induced rat peritoneal mesothelioma. R.H. Stevens, L.A. Will, D.A. Cole, et al. 1979;19(2):442-8. PubMed · Publisher

Abstract

Peritoneal mesotheliomas were induced through the intraperitoneal administration of Rhodesian chrysotile “A” to weanling male Holtzman rats. The intracellular concentrations of adenosine 3’,5’-cyclic monophosphate and guanosine 3’,5’-cyclic monophosphate were found to be significantly less than the levels measured in comparable control tissues obtained from age-matched animals that had been similarly administered charcoal instead of the asbestos. The calculated molar ratio of cAMP to cGMP was identical in tumors and control tissue implying that the two cyclic nucleotides were diminished by a constant factor in the tumor tissue. However, if tumorigenesis is related to cAMP/cGMP balance within the cancer cell, then in these apparently noninvasive lesions such an equilibrium exists as is found in cells of normal mesentery. These results indicate that asbestos-induced mesotheliomas are similar to other cancerous tissues of the digestive tract in that they contain less of the adenosine cyclic nucleotide than the normal tissue. The findings of this study suggest the possible loss of important cellular regulatory mechanisms in tumors induced by an important environmental carcinogen.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Historical background to the asbestos problem. D.H. Lee, I.J. Selikoff. 1979;18(2):300-14. Historical article PubMed · Publisher

Summary

The authors reviewed the history of asbestos use and of the recognition of asbestos-related disease, from prehistoric times to the 1960s. The article was condensed from the opening chapter of their monograph Asbestos and Disease. They described early uses, such as asbestos fibers in Finnish pottery dating from 2500 B.C. and asbestos lamp wicks and cremation cloths in classical antiquity. They then described the development of large-scale mining in Canada, South Africa, Italy, Russia, the United States, Rhodesia and elsewhere from the late 19th century. One table listed developments in manufacture. A second table gave United States chrysotile consumption in 1972 by end use, totalling 770,000 short tons. The review traced the recognition of harm through several milestones: an 1898 British women factory inspectors' report, Murray's 1899 postmortem of an asbestos worker, Cooke's reports from 1924, including his first use of the term "asbestosis" in 1927, and the 1930 Merewether and Price report to the British parliament. It described the later recognition of pleural plaques and calcification, mesothelioma and lung cancer. This included Wagner and colleagues' 1960 report of 33 pleural mesotheliomas, 28 with some association with the Cape asbestos field, and Doll's 1955 finding that men employed 20 or more years at a large asbestos works had 10 times the general population's lung cancer risk. The authors concluded that by the 1960s the essential evidence had been reported, but it rested largely on scattered small case reports. They stated that systematic epidemiological studies of large cohorts with adequate controls were needed.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.
Presence of fibers in the urine of a baboon gavaged with chrysotile asbestos. W.H. Hallenbeck, K.J. Patel-Mandlik. 1979;20(2):335-40. PubMed · Publisher

Abstract

Preliminary evidence is presented which indicates that chrysotile asbestos fibers can be recovered in the urine of a baboon which had been gavaged with chrysotile. This result supports the contention that ingested asbestos fibers can penetrate the gastrointestinal tract of man.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
The nature of electron diffraction patterns of amphibole asbestos and their use in identification. J.L. Hutchison, E.J. Whittaker. 1979;20(2):445-9. PubMed · Publisher
Asbestos cement dust inhalation by hamsters. A.P. Wehner, G.E. Dagle, W.C. Cannon, et al. 1978;17(3):367-89. PubMed · Publisher

Abstract

Two groups of 96 male Syrian golden hamsters were exposed to respirable asbestos cement aerosol at concentrations of approximately 1 and approximately 10 micrograms/liter, respectively, 3 hours/day, 5 days/week. Average fiber counts ranged from 5 to about 120 fibers/cm3. Each group was randomly divided into six subgroups of 16 animals. The first subgroup was sacrificed after 3 months of exposure, the second after 6 months, and the third after 15 months. The fourth subgroup was withdrawn from exposure after 3 months, observed for an additional 3 months, and then sacrificed. The fifth and sixth subgroups were withdrawn after 3 and 6 months of exposure, respectively, and maintained for observation up to the 15-month exposure point of the third subgroup at which time all surviving animals were sacrificed. All other experimental procedures were similar to those delineated in a previous publication describing the development of an animal model, techniques, and an exposure system for asbestos cement dust inhalation (A. P. Wehner, G. E. Dagle, and W. C. Cannon, 1978, Environ. Res. 16, 393-407). The asbestos cement exposures had no significant effect on body weight and mortality of the animals. Higher aerosol concentration and longer exposure times increased the number of macrophages and ferruginous bodies found in the lungs of the exposed animals. Recovery periods had no effect on the incidence of macrophages and ferruginous bodies. The incidence of very slight to slight fibrosis in the animals sacrificed after 15 months of exposure shows a significant (P less than 0.01) trend when the untreated control group and the 1 and 10 microgram/liter dose level groups are compared, indicating a dose-response relationship. Development of minimal fibrosis continued in animals withdrawn from exposure. No primary carcinomas of the lung and respiratory tract and no mesotheliomas were found.
Biochemical changes in guinea pig lungs due to amosite asbestos. V. Misra, Q. Rahman, P.N. Viswanathan. 1978;16(1-3):58-61. PubMed · Publisher
Biological effects of chrysotile after SO2 sorption. II. Effects on alveolar macrophages and red blood cells. M.C. Jaurand, J. Bignon, A. Gaudichet, et al. 1978;17(2):216-27. PubMed · Publisher

Abstract

An experimental study has been carried out using different biological and biochemical in vivo and in vitro tests for assessing the toxicity of natural UICC (A) chrysotile and SO2-sorbed UICC (A) chrysotile and for detecting a possible synergistic effect. For in vivo studies, rabbits received an intratracheal injection of chrysotile fibers suspended in physiological saline (PS). The control group received only PS; all animals were sacrificed after 68 hr. The alveolar free cells were harvested by pulmonary lavage. The results have shown that chrysotile induces a decrease in the free cell population but there was no significant difference in the number of viable cells or in the nature of cells harvested between the two chrysotile groups. Enzymatic activities of the alveolar macrophages from animals injected with SO2-sorbed chrysotile showed a significant increase of the enzymes LDH and acid phosphatases. The LDH increase could be related to the affinity of the enzyme regarding some chemical forms of SO2. In vitro studies using alveolar macrophages harvested by pulmonary lavage have shown no differences between the two chrysotile groups when cell viability and enzyme release were studied. The toxic effect was due to chrysotile fibers (decrease of 38% in cell viability and increase in cellular enzyme release when compared with control). When rabbit red blood cells were used, both natural and SO2 chrysotile fibers showed the same hemolytic activity. The failure to detect high differences between the two chrysotile groups may be related to the chemical form of sorbed SO2.
Development of an animal model, techniques, and an exposure system to study the effects of asbestos cement dust inhalation. A.P. Wehner, G.E. Dagle, W.C. Cannon. 1978;16(1-3):393-407. PubMed · Publisher

Abstract

An aerosol exposure system and procedures for delivering asbestos cement (AC) dust to the lungs of hamsters are described. Groups of hamsters were exposed to AC aerosol concentrations of 1 and 10 µg/liter, respectively, 3 hr/day. 5 days/week, for 3 and 6 months and were sacrificed for histopathologic examination. One subgroup from both the 1- and the 10-µg/liter exposure group was withdrawn from exposure after 3 months and sacrificed after a 3-month recovery period to determine whether or not some of the histologic changes might be reversible. There was an apparent dose-response relationship between AC exposure and the number of asbestos bodies and small randomly distributed foci of alveolar macrophages. No other treatment-related lesions were observed. The 3-month recovery period had no apparent effect.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Effects of asbestos on epithelioid cell lines. A.I. Neugut, D. Eisenberg, M. Silverstein, et al. 1978;17(2):256-65. PubMed · Publisher

Abstract

The in vitro effects of asbestos fibers on the growth and viability of CHO cells, an epithelioid cell line derived from Chinese hamster ovary, and on K-22 cells, an epithelial cell line derived from rat liver, have been studied. Relatively low concentrations of asbestos (10 micrograms/ml) were quite cytotoxic to both cell types. A sample of chrysotile asbestos was more toxic than samples of crocidolite or amosite. The toxic factor could not be extracted from the asbestos and toxicity occurred only if there was physical contact between the fibers and the cells. Although the phorbol ester class of tumor promoters induces the synthesis of plasminogen activator in various cell cultures, asbestos did not induce this protease in epithelioid or fibroblast cell cultures. The results obtained are compared to previous in vitro results obtained with fibroblast or macrophage cultures and are discussed in terms of their possible relevance to asbestos-induced fibrosis and tumorigenesis.
Exposure of employees to man-made mineral fibers: mineral wool production. N.A. Esmen, Y.Y. Hammad, M. Corn, et al. 1978;15(2):262-77. PubMed · Publisher

Abstract

This paper reports the results of a study in which employee exposure to mineral wool fibers in the mineral wool production industry was measured. Data for this study were collected in five plants operated by three different corporations. The results of the study indicate that the average exposure is about 0.1 to 0.5 fibers/ml. The results also indicate that despite operational diversities among the plants the size and length distributions of airborne fibers were consistent. It was also found that there is an excellent correlation between average total suspended particulate matter and average fiber exposure for types of work activity found in the plants.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Follow-up study of pleural hyalinosis in individuals not exposed to asbestos dust. M. Navrátil, K. Morávková, F. Trippé. 1978;15(1):108-18. PubMed · Publisher

Abstract

It was shown previously that the occurrence of pleural hyalinosis in a population with direct or indirect exposure to asbestos was of significantly higher importance than in a population without demonstrable exposure. It follows from recent results that the complicated form of pleural hyalinosis is due to direct asbestos exposure while a simple form is found in persons without any asbestos exposure within a 5-year follow-up period. Not even causes of death were connected with pleural processes in deceased persons during the follow-up time. The conclusion is reached that asbestos mineral retained in the lung and pleura is the main cause of pleural hyalinosis influencing its dynamics. However, it is not the only factor as proven by the same morphological findings in persons not exposed to asbestos. Follow-up dynamics of development shows ability of proliferation in hyalinosis only on the basis of long-term exposure to asbestos.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Mesothelioma after crocidolite exposure during gas mask manufacture. A.D. McDonald, J.C. McDonald. 1978;17(3):340-6. PubMed · Publisher

Abstract

Of 199 persons employed in the manufacture and handling of Canadian military gas mask canisters containing pure crocidolite, 1939 to 1942, by the end of 1975, 56 had died, 120 were still alive, and 23 could not be traced. Nine (16%) of the deaths were probably due to malignant mesothelioma, six involving the peritoneum. The risk of mesothelioma after crocidolite exposure appears to be many times greater than that after chrysotile.
On the utility of dark-field electron microscopy in the determination of the degree of deformation in chrysotile asbestos: an environmental research application. K. Seshan. 1978;16(1-3):383-92. PubMed · Publisher
The acute effects of chrysotile asbestos exposure on lung function. K.W. Harless, S. Watanabe, A.D. Renzetti. 1978;16(1-3):360-72. PubMed · Publisher
The adsorption of biological macromolecules by mineral dusts. R. Desai, R.J. Richards. 1978;16(1-3):449-64. PubMed · Publisher

Abstract

Evidence is presented that the absorptive capacity of various mineral dusts (asbestos, quartz, treated titanium dioxide samples) for complex mixtures of organic macromolecules (serum proteins, pulmonary surfactant) may be explained as a sum of their specific surface area, which partly determines the amount of material adsorbed, and their surface chemistry, which determines the specificity of binding. Both “weak” and “strong” adsorption reactions were noted with serum proteins, the latter being considered as the most specific for each mineral and perhaps the most important physiologically. The implications of the observed adsorption phenomena to the reaction between mineral particles, organic macromolecules, and cells ih Ritz and i/l r~itro are discussed.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
The effect of asbestos-associated metal ions on the binding of benzo(a)pyrene to macromolecules in vitro. R. Thomson, T.A. Kilroe-Smith, I. Webster. 1978;15(2):309-19. PubMed · Publisher

Abstract

In seeking an explanation for the high risk of malignancy in workers exposed to both asbestos and benzo(a)pyrene inhaled in cigarette smoke, experiments have been carried out to test the effect of asbestos-associated trace metals on the covalent binding of benzo(a)pyrene in vitro. Most of the metals tested—nickel, cadmium, chromium, zinc, manganese, and copper—caused an overall decrease in the binding of benzo(a)pyrene in microsomal incubations containing exogenous DNA. That this represented a reduction in the binding to DNA was confirmed in the cases of zinc, nickel, and chromium. Magnesium caused a very slight increase in binding, and ferrous and ferric ions, while reducing the binding to DNA, caused an increase in binding to some component of high molecular weight in the incubation mixtures, over a narrow concentration range. The significance of these findings is discussed in relation to the development of malignant disease associated with asbestos exposure.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
The effect of different mineral dusts on the mechanism of phagocytosis: a scanning electron microscope study. K. Miller, R.I. Handfield, E. Kagan. 1978;15(1):139-54. PubMed · Publisher

Abstract

Alveolar macrophages from normal rats were incubated with crocidolite asbestos fibers and quartz particles in vitro. The early events in phagocytosis were studied sequentially. Differences were found in the way in which macrophages recognized, attached, and phagocytosed the two dusts. Phagocytosis of quartz was extremely rapid: The macrophages typically developed long tenuous filopodia. Crocidolite was phagocytosed more slowly: Many macrophages developed large flattened pseudopodia. These different phagocytic mechanisms may reflect the different biochemical and cytotoxic properties of the dusts.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

In this test-tube study, dusts were added to rat lung scavenger cells (alveolar macrophages) growing on glass cover slips, not given to living animals or people. The cells came from normal adult male Wistar rats. Each culture received one of five materials: short crocidolite asbestos fibers (5 micrometres or less), long crocidolite fibers (20 micrometres or more), quartz particles, glass fibers, or Staphylococcus aureus bacteria. Samples were taken every 2 minutes for 30 minutes and examined with a scanning electron microscope. Both short and long crocidolite fibers were firmly attached to the cells after 4 minutes. With long fibers, many cells spread large flat extensions and swallowed the fibers end first. One 50-micrometre fiber was too long for any cell to take in, and long fibers were still present after 30 minutes. The cells handled glass fibers in a similar way. Quartz was swallowed within 2 to 4 minutes, and the cells put out long, thin projections. The authors concluded that the two dusts interact differently with macrophage membranes. They said the cause of the difference is not known, and that the study does not explain the different lesions of silicosis and asbestosis.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.
The effects of asbestos-cement dust inhalation on baboons. B. Goldstein, I. Webster, R.E. Rendall, et al. 1978;16(1-3):216-25. PubMed · Publisher
Asbestos bodies in lung parenchyma in relation to ingestion and inhalation of mineral fibers. O. Auerbach, E.C. Hammond, I.J. Selikoff, et al. 1977;14(2):286-304. PubMed · Publisher

Summary

After it became known in 1973 that Duluth, Minnesota tap water was heavily contaminated with amphibole (cummingtonite-grunerite) fibers from a taconite processing plant that opened in 1955, the authors asked whether ingested fibers reached the lungs and formed asbestos bodies. Using light microscopy, they counted asbestos bodies in 20 mm3 samples of autopsy lung tissue, ashed on specially designed grid slides and examined in coded random order. The subjects were 282 Duluth women from two hospitals who had lived in the city at least 15 years and had no occupational exposure, and who died in 1972-1973 (96), 1966-1967 (66), 1960-1961 (54) or 1953-1955 (66). They were compared with 96 age-matched New York City women. Men exposed at work, men living within half a mile of a Paterson, New Jersey amosite factory (19) and 19 age-matched New York men were also studied. No definite asbestos bodies were found in 33.3% of Duluth women who died in 1972-1973, compared with 24.0% to 30.3% in the other groups. Mean counts did not rise over time. For definite plus probable bodies, New York women had more in 58 of 96 pairs (P < 0.02). Paterson neighborhood men averaged 20.3 definite bodies versus 8.9 for New York men, which was not statistically significant. The authors concluded that drinking Duluth water did not greatly increase light-visible asbestos bodies in the lung. They stated that the study gave no evidence about smaller fibers.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.
Asbestos exposure in a Yale building. Analysis and resolution. R.N. Sawyer. 1977;13(1):146-69. PubMed · Publisher

Abstract

The Yale University Art and Architecture building has 118,000 sq ft (10,000 m²) of floor space and houses the School of Art, the School of Architecture, and the schools’ library. Completed in 1963, the nine-level reinforced concrete structure is a major building on the campus and has been used by over 2000 persons each academic year. The ceiling material in the building, a spray-applied mixture of asbestos and fibrous glass, caused occupant exposure to asbestos fibers under all conditions of usual activity. The measured asbestos fiber concentrations in some situations exceeded Occupational Safety and Health Administration allowable limits for industrial exposure, and in all cases were above the ambient city levels. Many air samples indicated potentially carcinogenic asbestos exposures. To eliminate this health hazard, the asbestos was removed from the building. Building isolation, protective equipment, surfactant treated water, and decontamination procedures afforded contamination control for the workers and the surrounding community. Ninety-two tons of wet asbestos-contaminated material was removed during a 20-day operation. Over 500 air samples were obtained during surveillance, experimentation, and asbestos removal. This report presents data obtained from 200 samples examined to date and outlines procedures used in the operation.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Explanation for the insensitivity to tilts of the electron diffraction patterns of amphibole asbestos fibers. K. Seshan. 1977;14(1):46-58. PubMed · Publisher
Leaching of chrysotile asbestos in human lungs. Correlation with in vitro studies using rabbit alveolar macrophages. M.C. Jaurand, J. Bignon, P. Sebastien, et al. 1977;14(2):245-54. PubMed · Publisher

Abstract

The chemical microanalysis of chrysotile fibers obtained from human lungs and from chrysotile phagocytosed in vitro by rabbit alveolar macrophages (AM) was carried out with the use of an energy dispersive spectrometer mounted on a scanning electron microscope (SEM). This microanalysis was compared to natural fibers in order to investigate the chemical stability of chrysotile in biologic residence. The Mg versus Si content was estimated by the ratio of the peaks intensity Si:Mg. Lung samples were obtained from workmen with definite asbestos exposure, and chrysotile asbestos was extracted by chemical digestion. Phagocytosed chrysotile fibers were obtained after incubating standard chrysotile (AWCC) with rabbit alveolar macrophages for 24 hours or 5 days. Both chrysotile fibers from human lungs and from in vitro incubation with AM have shown an increase of the Si:Mg ratio in respect to standard fibers. Moreover, the results have shown that the magnesium leakage was not constant along the fiber axis and was different from one fiber to another.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Some new perspectives on the biological effects of asbestos. Q. Rahman, P.N. Viswanathan, S.H. Zaidi. 1977;14(3):487-98. Review PubMed · Publisher
Surface charge and hemolytic activity of asbestos. W.G. Light, E.T. Wei. 1977;13(1):135-45. PubMed · Publisher

Abstract

Surface charge, represented by zeta potential, and hemolytic activity were measured for the five asbestos reference samples of the International Union against Cancer (UICC). Zeta potentials in distilled water at pH 7.4 for chrysotiles A and B were +40.5 and +52.5 mV, and for amphiboles crocidolite, amosite, and anthophyllite were -50.4, -58.5, and -54.0 mV, respectively. For fiber samples of equal surface area, chrysotiles had a greater hemolytic activity than amphiboles: 60.5 and 81.9% for chrysotiles A and B compared to 7.7, 9.8, and 15.7% for crocidolite, amosite, and anthophyllite, respectively. A lysing mechanism based on charge polarity is proposed to account for this difference in activity. Zeta potential and hemolytic activity were reduced by adding the main component of pulmonary surfactant, dipalmitoyl phosphatidylcholine (DPPC), to fiber suspensions. DPPC was more effective in decreasing both zeta potential and hemolytic activity for amphiboles than for chrysotiles. On the basis of these reductions, a significant correlation (r = 0.84) was found between zeta potential and hemolytic activity for all five UICC samples. This correlation suggests that surface charge is the principal factor in hemolysis by asbestos. The relevance of surface charge to asbestos toxicity is discussed.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
An examination of the fibrous mineral content of asbestos lung tissue from the Canadian chrysotile mining industry. F.D. Pooley. 1976;12(3):281-98. PubMed · Publisher

Abstract

An examination of postmortem lung tissue from 20 cases of diagnosed asbestosis from the Canadian chrysotile mining industry has shown that fibrous minerals other than chrysotile were present in many of the cases. Tremolite fiber was found in 11 of the cases, often in large amounts, and crocidolite and amosite fibers were found in 2 of the cases. Fibers corresponding to talc and anthophyllite were found in 3 cases. In 4 of the cases fibers were not detected. Amphibole and other fibers were found to be present in larger numbers than chrysotile in 7 of the cases. No attempt has been made to relate the results to occupation and location where the exposures may have occurred. It is possible, however, that fibrous minerals other than chrysotile are active in the incidence of asbestosis in the Canadian chrysotile mining industry.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Asbestos exposure control at Puget Sound Naval Shipyard. R.R. Beckett. 1976;11(2):248-60. PubMed · Publisher
Asbestos exposure during brake lining maintenance and repair. A.N. Rohl, A.M. Langer, M.S. Wolff, et al. 1976;12(1):110-28. PubMed · Publisher
Asbestos related disease in Barrow-in-Furness. J.R. Edge. 1976;11(2):244-7. PubMed · Publisher

Summary

The author described asbestos-related disease in Barrow-in-Furness, a British shipbuilding town where asbestos use peaked before and during World War II and captured German ships were stripped and refitted after the war. A 1968 radiographic survey of every tenth shipyard workman found pleural plaques in about 6% and pulmonary fibrosis in under 0.5%. Among 100 consecutive autopsies in 1970, 35 of 72 men had plaques. Since 1966, 28 histologically confirmed pleural mesotheliomas had arisen. The average time since first exposure was 35 (20-45) years, and the average survival after diagnosis was 18 (5-35) months. In a prospective study, 235 men with plaques were followed for 4 years or more. Of these, 70 died: 17 from mesothelioma and 13 from bronchial carcinoma, against 5.4 bronchial carcinoma deaths expected (2.4 times; P = 0.001). The author also compared 156 men with plaques with 156 age-matched men with normal radiographs taken in 1962-1969. The plaque group had 48 versus 28 deaths, 8 versus 3 bronchial carcinoma deaths, and 13 versus 2 mesothelioma deaths. Autoantibody levels in 160 men with plaques did not differ significantly from those in the general British population. The author concluded that shipyard workers with plaques, without fibrosis, had a 2.5 times increased risk of bronchial carcinoma, and that these serological tests were unlikely to be useful for screening.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.
Depression of viral interferon induction in cell monolayers by asbestos fibers. N. Hahon, H.L. Eckert. 1976;11(1):52-65. PubMed · Publisher

Abstract

Studies on the induction of interferon by influenza virus revealed that this adaptive cellular response was depressed, completely or partially, in either amosite, crocidolite, anthophyllite, Canadian or Rhodesian chrysotile-treated monkey kidney (LLC-MK2) cell monolayers. Asbestos fiber concentrations of 1 mg/1.0 × 10^7 cells, which minimally affected cell viability, depressed interferon production by almost 90%. Increases in the virus-cell multiplicity of infection did not significantly increase interferon yields in asbestos fiber-treated cells. Chrysotile B fibers of lengths ranging from 10 to 5 µm were more effective in reducing interferon yields than those ranging from 75 to 625 µm. Maximal depression of interferon production was dependent on prior treatment of cell monolayers with asbestos fibers before the addition of viral inducer. The processes of virus integration (attachment and penetration) into and virus multiplication in cells were unaffected by the presence of asbestos fibers, however, a slightly higher level of virus replication was noted in asbestos fiber-treated cells. When cells were primed with interferon, the presence of asbestos fibers did not interfere with the ability of the primer to enhance interferon production. Neither interferon antagonists, interference with virus-cell interactions, nor adsorption by asbestos fibers accounted for the depression of interferon yields. These findings suggest that asbestos fibers act on cell membranes in a manner, as yet undetermined, to interpose in the viral inductive process of interferon synthesis.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Early response of gastric mucosa to ingested asbestos dust and the dissolution of nickel. S.H. Zaidi, G.S. Gupta, Q. Rahman, et al. 1976;12(2):139-43. PubMed · Publisher

Abstract

The gastric response evoked by asbestos fibers (chrysotile, tremolite, anthophyllite, and amosite) was studied in guinea pigs 6 hours after oral administration. Substantial amounts of nickel were leached from the dusts into the gastric juice, the maximum being with chrysotile. Histopathological examination of stomach and biochemical analysis for total acidity, peptic activity, and the contents of mucin did not reveal any alterations of significance.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Epidemiology of mesothelioma in Israel. C. Lemesch, R. Steinitz, M. Wassermann. 1976;12(2):255-61. PubMed · Publisher

Abstract

During the period 1960-1972, 65 cases of mesothelioma were registered at the Israel Cancer Registry. In 13 cases the histologic diagnosis was not considered as definite and they were, therefore, excluded. A review of the medical and occupational histories where available of the remaining 52 cases reported. The diagnosis was made by biopsy in 34 cases (65%) and by autopsy in 18 cases (35%). Twenty-seven cases (52%) were located in the pleura and 25 (48%) in the peritoneum. There were 30 males (58%) and 22 females (42%). The age at diagnosis ranged from 1.5 to 85 years and the highest age-specific rate (5.0/million) corresponded to the age group 66-74 years. The average annual incidence rate for the total population was 1.5 cases per million. Distribution by country of origin showed that Jews born in Europe or America had the highest incidence rate (3.4/million) and the lowest rate (0.6/million) was found among Jews born in Israel. The age-standardized rates indicated that these differences were due to a dissimilar age distribution among the country of origin groups. Only one case had a definite occupational history of exposure to asbestos. It is suggested that, in addition to occupational exposure other etiological factors may play an important role in the epidemiology of mesothelioma in Israel.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Experience with asbestos disease and its control in Great Britain's naval dockyards. P.G. Harries. 1976;11(2):261-7. PubMed · Publisher

Summary

The author described experience with asbestos exposure, asbestos disease and its control in British naval dockyards. Past measurements recorded 177-322 f/cc during spraying of crocidolite (1940-1960) and 50-500 f/cc, locally up to 2,000 f/cc, during its removal. The dust spread through ships to men not working with asbestos. Substitute materials, respiratory protection and improved codes of practice had since greatly reduced fiber concentrations. Pilot radiographic surveys in four dockyards found asbestos abnormalities in 3% of men examined. Preliminary results of complete surveys showed abnormalities in 893 (8%) of 10,849 persons. At Devonport Dockyard, Plymouth, 156 men were awarded disability pensions for asbestosis in the 10 years to September 1973, and most had worked near insulation workers. Of 457 men with pleural abnormalities, 103 had calcified plaques, 285 uncalcified plaques and 69 diffuse fibrosis. There were 55 mesothelioma deaths in Plymouth over the same period, and only two of these men were asbestos workers. Previous radiographs of 44 cases showed plaques in 15 (34%), compared with an expected 12% in similarly exposed survey groups. The author concluded that hygiene improvements would prevent disease in future employees. He also concluded that research into detecting susceptible persons, especially immunological research, should receive urgent priority.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.
Industrial hygiene and occupational health studies in Australian (New South Wales) shipyards. A. Bell. 1976;11(2):198-212. PubMed · Publisher

Summary

This paper, presented as an address, described occupational health enquiries and evaluations carried out in shipyards in the previous few years by the Division of Occupational Health and Pollution Control of the Health Commission of New South Wales, Australia. The commonest problems were welding, noise, asbestos and solvents. In welding investigations, done mainly at the request of union representatives, four were judged hazardous. Total fume in the breathing zone frequently exceeded 15 mg/m3 when men welded over coated surfaces. In standardized tests of seven paints welded in a small compartment of a tug, the threshold limit was exceeded in the welder's breathing zone eight times out of ten. With local ventilation working, carbon monoxide, nitrogen dioxide, manganese, zinc and chromium did not exceed threshold limits. With it off, all manganese and zinc values exceeded them. In most noise assessments there was considerable risk of noise-induced deafness. Of 21 asbestos work situations investigated between 1968 and 1972, five were judged unsatisfactory and dust control was recommended. These included hand cutting and edge smoothing of dry laminated asbestos board, boring holes and jigsaw cutting of board, wet spray application of asbestos, and air discharged from a local exhaust system. Unsatisfactory practices were still frequently seen. The author also reported three cases of lung mesothelioma in welders outside shipyards who had used homemade rods wrapped in crocidolite. Tests with an unused packet gave 16 to 18 fibers per cubic centimeter. Four solvent incidents in which workers were overcome were described. The author concluded that Australian shipyards, though comparatively small, had potentially dangerous work situations.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.
Light microscope studies on the effects of chrysotile asbestos and fiber glass on the morphology and reticulin formation of cultured lung fibroblasts. R.J. Richards, F. Jacoby. 1976;11(1):112-21. PubMed · Publisher

Abstract

Chrysotile asbestos is highly cytotoxic when initially added to cultured lung fibroblasts, and this is reflected by cell death and by nuclear, nucleolar, and cytoplasmic abnormalities. Renewed growth and recovery of the culture occurs, but the subsequent deposition of reticulin is atypical. The results presented are correlated with earlier biochemical studies and subsequent electron microscopical investigations. Fiber glass causes little cell destruction, yet produces similar morphological changes but to a much lesser degree.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Shipyard health problems. B.G. Ferris. 1976;11(2):140-50. PubMed · Publisher
The effect of amostie and chrysotile asbestos on the clearance of TiO2 particles from the lung. J. Ferin, L.J. Leach. 1976;12(2):250-4. PubMed · Publisher

Abstract

It is well known that the pulmonary system encompasses pathways by which foreign materials can be removed from the body. The defense mechanisms involved in this removal, are presently being examined closely in order to more fully understand the complex interactions between the lung parenchyma and airborne agents. In the experiments described here, techniques have been developed to assess the effects of air pollutants on the alveolar clearance pattern of inert particles deposited in the lungs of laboratory animals. Amosite or chrysotile asbestos exposures, relatively short in duration (1-3 hours) and high in concentration (- 10 mg/m3) depressed the alveolar clearance of titanic oxide (TiO2) particles in rats. This effect was not observed when asbestos air concentrations were reduced to about 10X the Threshold Limit Value (TLV) estimated to be - 0.1 mg/m3. Extending the postexposure observation period and the number of exposures to 11 or 22 a suppressive effect on TiO2 clearance was seen. How important this late effect is can not be determined at this time. However, the effect of high concentrations of amosite or chrysotile at exposures lasting only a short time should be considered with concern.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
The reliability of measures of amphibole fiber concentration in water. A.L. Brown, W.F. Taylor, R.E. Carter. 1976;12(2):150-60. PubMed · Publisher

Abstract

Water samples from four communities whose source of drinking water is Lake Superior and from one site in the lake itself were examined in eight laboratories by electron microscopy to determine the concentration of amphibole fibers. The number of sites and samples from each site were unknown to the laboratories. Laboratories differed widely, both between and among themselves, in the concentrations reported when aliquots from the same sample of water were examined. Some laboratories varied much more than others. However, the relative variability among laboratories was reasonably uniform. There was general agreement that water from some sites was consistently high in concentrations of amphibole fibers, while other sites were consistently low. We conclude that comparisons of water concentrations of amphiboles at two sites or under two different sets of circumstances as determined by electron microscopy can be done if at least two provisions are fulfilled: (1) all concentration measurements must be made in the same laboratory using the same equipment and the same technician and (2) several aliquots of each sample of water must be examined independently.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Analysis of particles in stomach tumours from Japanese males. W.J. Henderson, D.M. Evans, J.D. Davies, et al. 1975;9(3):240-9. PubMed · Publisher

Abstract

The particulate material present in stomach tumours removed from Japanese males has been investigated. An extraction-replication technique used in association with electron microscope-microanalysis provided evidence for the presence in the tumour tissue of kaolin, talc, aluminium and calcium silicates and some types of asbestos fibres.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Chronic inhalation of asbestos and cigarette smoke by hamsters. A.P. Wehner, R.H. Busch, R.J. Olson, et al. 1975;10(3):368-83. PubMed · Publisher

Abstract

One hundred and two male Syrian golden hamsters received chronic exposures to a respirable aerosol of Canadian chrysotile asbestos (mean aerosol concentration = 23 µg/l) 7 hours per day, 5 days per week. Half of the animals were also exposed for 10 minutes to cigarette smoke in modified Hamburg II smoking machines, three times per day, 5 days per week, for the duration of their life span. The other half of the animals received sham-smoke exposures. Another group of 102 hamsters served as controls. Half of the controls received smoke exposures, the other half received sham exposures. Asbestos exposure resulted in earlier and more severe lung lesions than in identical groups of concurrent experiments, which had received life span exposures to aerosols of NiO (53 µg/l) and CoO (10 µg/l), or which were treated with diethylnitrosamine (12 × 0.25 mg by s.c. injection). Asbestosis developed in all animals and forced discontinuation of the asbestos exposures after 11 months. Of 12 lung adenomas found in 510 hamsters, ten occurred among the 102 animals of the asbestos-exposed groups, indicating an early neoplastic response. However, perhaps on account of their significantly shorter life span due to asbestosis, the incidence of laryngeal lesions and of malignant tumors was significantly lower in the asbestos + smoke-exposed group than in the control group having received smoke exposures. Neither a carcinogenic effect of asbestos nor a cocarcinogenic effect of cigarette smoke was observed. Cigarette smoke inhalation resulted in significantly lower mean body weights of the smoke-exposed groups.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This was an experiment in male Syrian golden hamsters. 102 hamsters breathed a dust of Canadian chrysotile asbestos (average 23 micrograms per liter of air) 7 hours a day, 5 days a week. Half also breathed cigarette smoke three times a day; half got sham smoke. Two control groups of 51 got smoke or sham smoke without asbestos. All asbestos-exposed hamsters developed asbestosis. Asbestos exposure stopped after 11 months because of breathing problems and failing health. No asbestos-exposed hamster developed primary lung cancer. Pleural changes in several animals were inflammation and scarring, with no sign of malignancy. Of 12 lung adenomas among 510 hamsters in the wider program, 10 were in asbestos groups. The asbestos-plus-smoke group had significantly fewer laryngeal lesions and malignant tumors than smoke-only controls, which the authors suggested was possibly due to earlier death from asbestosis. The authors observed no cancer-causing effect of asbestos and no cancer-promoting (cocarcinogenic) effect of smoke in this experiment. They concluded this dose was too high for cancer studies, as early deaths from massive asbestosis might reduce or remove the chance for cancers to develop.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.
Cytogenetic studies on chrysotile asbestos. K.S. Lavappa, M.M. Fu, S.S. Epstein. 1975;10(2):165-73. PubMed · Publisher

Abstract

The cytogenetic effects of chrysotile asbestos (chrysotile A) in vivo in Rhesus monkeys and Swiss albino mice, and in vitro in embryonic hamster cells were investigated. Single oral dosages of chrysotile, 100 or 500 mg/kg, failed to induce chromosome aberrations in bone marrow cells of Rhesus monkeys. Similarly, oral or intraperitoneal administration of chrysotile over a dose range from 0.4 to 400 mg/kg. failed to induce micronuclei formation in bone marrow cells of mice. However, chrysotile induced a significant and dose-related increase in chromosome aberrations and a dose-related inhibition of the mitotic index of cultured Syrian hamster embryo cells.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Studies on the deposition of inhaled fibrous material in the respiratory tract of the rat and its subsequent clearance using radioactive tracer techniques. A. Morgan, J.C. Evans, R.J. Evans, et al. 1975;10(2):196-207. PubMed · Publisher

Abstract

The distribution of fibre deposited during 30 minute inhalation exposure of rats to the UICC standard reference samples was investigated. These samples were made radioactive by neutron irradiation, which enabled the amount of asbestos in various tissues to be determined radiometrically. The total amount of fibre deposited varied from 31 to 68% of that respired and, on average, 17% remained in the lower respiratory tract (alveoli and conducting airways up to and including the trachea) at the end of exposure. Activity median aerodynamic diameters (AMADs) of the materials used were measured with the cascade centripeter. Differences in the total deposition of inhaled fibre, and in the distribution of deposited material, were correlated with the AMADs of the various samples. Autoradiographs of lung sections showed that at the termination of exposure, fibre was present in the conducting airways, particularly at bifurcations, and also distributed relatively uniformly throughout the alveolated regions.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
The dose-dependent effects of ingested chrysotile on DNA synthesis in the gastrointestinal tract, liver, and pancreas of the rat. D.E. Amacher, A. Alarif, S.S. Epstein. 1975;10(2):208-16. PubMed · Publisher

Abstract

The effects of single oral administration of saline suspensions of chrysotile A to fasting male albino rats on DNA synthesis in the GI tract, pancreas, and liver were studied after a subsequent interval of 3 days. Incorporation of [3H]TdR was elevated in the whole stomach, duodenum, and jejunum following administration of chrysotile in the dose range of 5 to 100 mg/kg; incorporation in the liver was, however, reduced. There was no change in pancreatic and colonic [3H]TdR uptakes following administration of chrysotile. Preliminary data suggest that physicochemical alterations of chrysotile by gastric acid may influence its subsequent effects on DNA synthesis.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Inhalation carcinogenesis from various forms of asbestos. A.L. Reeves, H.E. Puro, R.G. Smith. 1974;8(2):178-202. PubMed · Publisher

Abstract

Rats, rabbits, guinea pigs, gerbils, and mice were exposed to the inhalation of chrysotile, crocidolite, or amosite for 2 years. Mean atmospheric concentrations were 47.9-50.2 mg/m³, but only 0.08-1.82% of the dusts retained fibrous morphology during the dissemination procedure which involved hammer milling. Trace contamination especially by chromium and nickel was also increased. Light microscopic fiber counts per ml chamber air were 54 (chrysotile), 1105 (crocidolite), and 864 (amosite). A fibrogenic response to these dusts was observed in all five animal species, the severity corresponding to the extent of exposure (with reaction to chrysotile frequently very slight). Gerbils developed frequent alveolar proteinosis. Mice developed spontaneous papillary carcinomas in the lungs. Disregarding the latter species, carcinogenic response to asbestos inhalation was restricted to rats and occurred in all three exposure groups. There were 2 lung cancers and 1 pleural mesothelioma after chrysotile inhalation; 4 lung cancers after crocidolite inhalation; and 1 lung cancer and 2 pleural mesotheliomas after amosite inhalation. These cases constituted 7-9% incidence of malignancy among rats with adequate survival record. Hypotheses of asbestos carcinogenesis are reviewed and it is suggested that different etiologic principles may be involved in the causation of lung cancer and of pleural mesothelioma.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
A study of workers exposed to asbestiform minerals in commercial talc manufacture. M. Kleinfeld, J. Messite, A.M. Langer. 1973;6(2):132-43. PubMed · Publisher
Development of pleural hyalinosis in long term studies of persons exposed to asbestos dust. M. Navrátil, J. Dobiás. 1973;6(4):455-72. PubMed · Publisher

Summary

The authors studied how pleural hyalinosis (pleural plaques and thickening) developed over time in workers exposed to asbestos (chrysotile), and how it related to asbestosis and to pleural mesothelioma. The subjects were employees and pensioners of a Czechoslovak factory making asbestos textiles, friction materials, asbestos metal products and boards. The authors had followed them since 1953, with X-ray screening of all employees and pensioners from 1966. Fifty persons had pleural hyalinosis. Twenty-five also had asbestosis (15 men, 10 women) and 25 had no radiologic signs of asbestosis (18 men, 7 women). By August 1, 1972, 10 persons (40%) had died in the asbestosis group and 3 (12%) in the other group, a statistically significant difference (p < 0.05). The groups had similar age at death (64 and 66 years) and length of exposure (22.4 and 21.0 years). Bronchogenic cancer caused four deaths in the asbestosis group. One pleural mesothelioma was proved at autopsy and a second was diagnosed clinically. Among 35 persons followed for more than five years, the authors described two forms. 'Hyalinosis simplex' progressed gradually. 'Hyalinosis complicata' was marked by sterile pleural effusion followed by diffuse pleural thickening and restrictive functional impairment. The complicated form occurred in 6 of 23 persons with asbestosis and 1 of 12 without, and was associated with higher mortality. The authors concluded that pleural hyalinosis in asbestos-exposed workers is not rare, develops gradually and has a long latency. They drew no firm conclusions about the complicated form because the numbers were small.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.
Experimental infective pneumoconiosis: effect of asbestos dust and Candida albicans infection on the lungs of rhesus monkeys. S.H. Zaidi, R. Shanker, R.K. Dogra. 1973;6(3):274-86. PubMed · Publisher

Abstract

The combined effect of Candida albicans, a facultative pathogen in the normal physiological condition in the throat of miners, and amosite dust produces after intratracheal inoculation extensive collagenous fibrosis at 330 days in rhesus monkeys. The lesions produced by amosite dust alone comprise fine reticulin fibrosis around bronchioles and blood vessels and moderate interstitial fibrosis. The C. albicans infection alone caused acute inflammatory reaction in the early stages while at the termination of experiment (330 days) the only evidence of pulmonary candidiasis was a few small fibrotic foci of compactly arranged reticulin fibers.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Studies on the deposition of inhaled fibrous material in the respiratory tract of the rat and its subsequent clearance using radioactive tracer techniques. 1. UICC crocidolite asbestos. J.C. Evans, R.J. Evans, A. Holmes, et al. 1973;6(2):180-201. PubMed · Publisher

Abstract

Radioactive tracer methods were used to study the distribution of crocidolite between the upper and lower respiratory tracts after single short inhalation exposures of the "nose only" type. With the UICC standard reference sample of crocidolite, it was found that 50 ± 5% of the deposited asbestos was in the lower respiratory tract. After 30 days the lung content of crocidolite had been reduced to 73% of the initial value. Autoradiography was used to study the distribution of asbestos within the lung immediately after exposure and after 30 days. The clearance of crocidolite from the respiratory tract was also followed by the measurement of radioactivity in faeces.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
A survey of pleural thickening: its relation to asbestos exposure and previous pleural disease. 1972;5(2):142-51. PubMed · Publisher
Acute pleurisy in asbestos exposed persons. G.K. Sluis-Cremer, I. Webster. 1972;5(4):380-92. PubMed · Publisher

Abstract

It has been clinically observed that pleural effusion occurs, not infrequently, in asbestos exposed persons with or without evidence of asbestosis. Nine such cases are presented, in seven of these, pleural biopsy has been carried out by needle or by open thoracotomy. The histological features are described. The suspicion of mesothelioma of the pleura necessarily arises in such cases. This problem is discussed.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Asbestos bodies, their formation, composition and character. F.D. Pooley. 1972;5(4):363-79. PubMed · Publisher

Abstract

Asbestos bodies extracted from human lungs have been examined under the electron microscope to determine their morphology and diffraction characteristics. The asbestos bodies were extracted from the lungs of persons exposed to the four types of commercial asbestos fiber, namely crocidolite, amosite, anthophyllite and chrysotile. Asbestos bodies were rarely formed on fibers less than 10 µm in length and practically always on straight fibers. They were found to occur on all the four commercial varieties of asbestos but less frequently on chrysotile fibers. The characteristics of the individual fibers were found to play a large part in determining the range and frequency of body shapes observed. There appears to be no evidence to suggest stepwise formation of asbestos bodies. Asbestos bodies were found to have a major crystalline component which is structurally similar to extracts of ferritin produced from animal and human organs. The material forming the asbestos body is definitely biological in origin and corresponded closely to the material defined in the medical literature as hemosiderin.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Prevalence of pleural calcification in persons exposed to asbestos dust, and in the general population in the same district. M. Navrátil, F. Trippé. 1972;5(2):210-6. PubMed · Publisher

Abstract

It is of interest whether pleural calcification is primarily the result of long years of exposure to asbestos dust or whether there are factors other than exposure to dust. We have investigated persons working for a long period in a plant processing asbestos products (chrysotile), persons without occupational exposure to dust but living in the vicinity of the plant, and consanguineous relations of patients with pleural calcifications. We have also studied a large population above the age of 40, in the district in which the plant is situated. Comparison of the groups disclosed that prevalence of pleural calcifications was closely related to opportunity for exposure to asbestos dust either occupationally or by family or neighborhood contact, as contrasted with the unexposed population. The prevalence in the group with direct or indirect asbestos exposure was 5.3, 5.8, 3.5%; whereas in the unexposed population it was 0.34%. These results indicate that asbestos is primarily responsible for pleural findings, but that some pleural disease may be the result of the other factors, still not known. The identification of other causes is hampered by the long period which need elapse from the onset of the process to the radiological appearance of the pleural change.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Electron diffraction patterns of U.I.C.C. asbestos samples. M.I. Skikne, J.H. Talbot, R.E. Rendall. 1971;4(2):141-5. PubMed · Publisher

Abstract

The U.I.C.C. standard samples of amosite, anthophyllite, crocidolite, chrysotile A, ;und chrysotile B have been studied by electron diffraction. The effect of fibre orientation on the electron diffraction patterns was studied using a double-tilt stage. Rotation did not have a nurked effect on the general pattern of weak and strong spectra. It has been shown that electron diffraction nlethod may ha nsed to identify Sin& fib-es of the samples.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Hemolysis by asbestos. J.S. Harington, K. Miller, G. Macnab. 1971;4(2):95-117. PubMed · Publisher

Summary

This laboratory study examined how different types of asbestos and other minerals damage (lyse) red blood cells in vitro, how acidity (pH) affects this, and which chemical agents prevent it. Fourteen mineral dusts and fibers were tested, including Union Internationale Contre le Cancer (U.I.C.C.) standard reference asbestos samples. In the standard test, 50 mg of mineral was incubated with sheep erythrocytes in buffered saline for 50 minutes at 37°C, and the hemoglobin released was measured. Chrysotile lysed erythrocytes completely within 10 minutes over a pH range of 4-11. It was hemolytic to erythrocytes of all nine animal species tested. Amosite and crocidolite were relatively inactive on sheep cells (about 10%) but more active on cells of other species. Over 4 hours, their activity increased; with human erythrocytes it rose from 21% to 45% and from 15% to 44%. In nine forms of asbestos, hemolytic activity was related to the magnesium:silicon ratio. Adding specific surface area did not improve this relationship. EDTA (100 micromolar) reduced chrysotile hemolysis from 78% to 32% at a starting pH of 6.2, but had no effect at a starting pH of 7.2. PVPNO, which prevents hemolysis by silica, had little effect on chrysotile. Sialic acid reduced chrysotile hemolysis by 73%. The authors concluded that magnesium is the principal reactant on the chrysotile surface. They suggested that sialic acid on the erythrocyte surface may be the main group it reacts with. They also reported a tentative association between hemolytic activity and cytotoxicity.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.
The synthesis of tritium-labeled asbestos for use in biological research. A.C. Turnock, S. Bryks, F.D. Bertalanffy. 1971;4(2):86-94. PubMed · Publisher

Abstract

To synthesize tritium-labeled chrysotile asbestos applicable to studies of its biological effect on respiratory tissue, two series of experiments were carried out. Firstly, chrysotile asbestos was synthesized from periclase MgO, amorphous SiO2, and tritiated water. The resulting material was well labeled but the shape of the particles was in part nonacicular. Secondly, natural chrysotile was maintained in the presence of tritiated water at 300° for 20 days in order to produce an exchange of structural hydroxyls with tritium-oxyls (OH3). This procedure yielded well labeled material, acicular in shape of particles. Such labeled chrysotile dust was employed to accurately localize this material in lung tissue by means of the radioautographic technique; furthermore, clearance of this dust from the lung could be accurately quantified by scintillation counting.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Asbestos hemolysis. R.J. Schnitzer, F.L. Pundsack. 1970;3(1):1-13. PubMed · Publisher

Abstract

Chrysotile fibers exert a marked hemolytic activity on suspensions of washed sheep erythrocytes, but amphibole asbestiform minerals such as crocidolite, amosite, tremolite, and anthophyllite possess only negligible hemolytic properties. The minimal hemolytic concentration of chrysotile asbestos is dependent on the openness of the fibers as characterized by the air permeability surface area and decreases with increasing surface area. This fact was also observed in the evaluation of hemolysis of fibrous, nonasbestiform minerals, e.g., sepiolite and nemalite. Chrysotile hemolysis can be inhibited by disodium ethylenediaminetetraacetic acid (EDTA) and by certain acidic polymers particularly by polystyrene sulfonates, carboxymethylcellulose ether sodium salt (CMC), and the pyran-copolymer NSC 46015. These substances are not effective as inhibitors of silica (quartz) hemolysis, whereas polyvinylpyridine-N-oxide (PVPNO), a very potent antagonist of silica hemolysis, interferes with chrysotile only at high concentrations. The hemolytic action of chrysotile can be markedly reduced by repeated treatment with red blood cells. The mechanism of asbestos hemolysis cannot yet be satisfactorily interpreted. There is a marked correlation of hemolytic potency with the surface area and the degree of opening of the fibers which may be influenced by the action of the antagonistic polymers. The role of the magnesium hydroxide surface characteristic for chrysotile is not yet elucidated, because magnesium hydroxide is not hemolytic, although nemalite, a natural fibrous magnesium hydroxide, and a lightly burned magnesium oxide are active hemolytic agents.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Asbestosis in South African asbestos miners. G.K. Sluis-Cremer. 1970;3(4):310-9. PubMed · Publisher

Summary

This study examined how long after first exposure asbestosis appeared, and at what rate it was being produced, in South African crocidolite (North West Cape) and amosite (Northern Transvaal) asbestos mines. The author followed white miners employed in these mines between 1954 and 1958, as far as the mine records, which were incomplete, allowed. The groups numbered 391 in the North West Cape and 147 in the Transvaal. Each man's last X-ray at the Miners' Medical Bureau was read. Vital capacity and carbon monoxide diffusion (DCO) were measured in white North West Cape miners without radiological asbestosis. Autopsy findings in Bantu labourers who died between 1965 and 1969 were also reviewed.

Radiological diagnoses of asbestosis increased with length of service. One case in each area was diagnosed after less than 5 years' service and 15-19 years of follow-up. Calcified pleural plaques generally did not appear within 20 years of first exposure. No man who started work in 1954-1958 developed bronchial carcinoma or mesothelioma. Two bronchial carcinomas and one pleural mesothelioma occurred in men who started earlier.

At autopsy, asbestosis, mainly slight, was common in Bantu labourers after relatively short recorded service. It was less frequent than in a 1959-1964 series (71.5% and 79.7%). DCO showed no significant fall with service. Vital capacity fell with service only in men aged 40-49, and no result was definitely abnormal. The author concluded that both length of exposure and time since exposure matter, and that the disease may progress after exposure stops.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.
Formation of the asbestos body. A comparative study with three types of asbestos. Y. Suzuki, J. Churg. 1970;3(2):107-18. PubMed · Publisher

Abstract

.Asbestos bodies were produced experimentally in the lungs of hamsters by intratracheal instillation of three types of asbestos: soft chrysotile, harsh chrysotile, and amosite. Though some differences were noted, harsh chrysotile and amosite fibers were converted into asbestos bodies by the same snccessive steps that were prrvion\ly described for soft chrysotilr: [ 1) phagocytosis of asbestos by alveolar nlac ophages and other phagocytic cells and incorporation into phagolysosomes; (2) accumulation of iron micelles around the fibers, possibly by fusion of asbestos-containing phagosomes with hemosiderin granules; and (3) compaction of the micelles and clearing of the peripheral zone, to form a mature asbestos body. Formation of asbestos bodies seems to be a continuous process with old bodies growing in thickness and uncoated fibers being converted into bodies months 01 !.rars after instillation of asbestos. Possible origins of hemosiderin granules are discussed. Striking hyperplasia of cell organelles was fonntl. presm~lably intlicativr of their participation in the tlc~vclopment of the asbestos bodies.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.
Radiological features of diffuse mesothelioma. A. Solomon. 1970;3(4):330-8. PubMed · Publisher

Summary

This article described the chest X-ray appearances of diffuse pleural mesothelioma in a retrospective radiological study of 23 cases whose pathology had been confirmed by the Asbestos Tumour Reference Panel of South Africa. The author worked at the Pneumoconiosis Research Unit in Johannesburg and Baragwanath Hospital, Transvaal. Many patients had worked in asbestos mining. Some had not handled asbestos but had lived in areas where it was mined and milled. Nine had been born in, and lived for many years in, "calcific areas". The youngest patient was 21. Pleural effusion was the main X-ray feature in 14 cases. Six cases showed a lobular pleural tumour with no obvious effusion. Lobular pleural masses were seen in 15 patients, and in six of these, aspiration of fluid with an induced pneumothorax was needed to show the tumour. Hilar masses on the tumour side were present in six cases and extrathoracic soft-tissue masses in three. One patient presented with a hydropneumothorax. Parenchymal lung changes were seen in five cases, non-calcified pleural changes on the opposite side in seven, and pleural calcification in two. Eighteen cases had no significant radiological signs of parenchymal fibrosis. The author recommended introducing a small amount of air into the pleural cavity, and taking decubitus views, when only an effusion is seen. He considered a hilar mass in an asbestos-exposed person ominous once tuberculosis is excluded.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.
Radiology of asbestosis. A. Solomon. 1970;3(4):320-9. PubMed · Publisher

Summary

This article described the chest X-ray appearances of asbestosis in South African asbestos miners. The author reviewed the X-rays of 43 deceased asbestos workers whose chests had been X-rayed during their working lifetime. Most films were frontal chest radiographs. All the men had worked in crocidolite or amosite mines, and, as far as was known, in no other form of mining. Cases with complicating factors such as tuberculosis or neoplasms were excluded, so the review concerned uncomplicated asbestosis. The ore-bearing rock was noted to contain up to 40% free silica and substantial iron minerals. Findings included costophrenic blunting, noncalcified plaques along the lateral chest wall, calcified plaques, and fine, nodular, coarse and massive lung fibrosis. Serial X-rays of a father and son over 7 and 10 years showed early pleural calcification patterns that stayed unchanged apart from becoming denser. Massive fibrotic lesions of 2 to 10 cm were seen in six cases, without cavitation or calcification. No hilar lymph gland calcification or enlargement was seen, and no difference in lung patterns was attributed to amosite versus crocidolite. The author concluded that exposure, lung fibrosis and peripheral soft-tissue plaques together make the radiological diagnosis almost conclusive. Combined pleural and lung lesions were common. In South Africa, massive fibrosis was more common in asbestosis than in gold and coal workers' pneumoconioses, and basal massive fibrosis with pleural changes was almost diagnostic of asbestosis.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

1960s

Asbestos minerals in modern technology. S. Speil, J.P. Leineweber. 1969;2(3):166-208. PubMed · Publisher
Pleural fibrocalcific plaques and asbestos exposure. L.O. Meurman. 1968;2(1):30-46. Review PubMed · Publisher

Summary

This article reviewed published evidence on the association between calcified (fibrocalcific) pleural plaques and asbestos exposure. The author noted that pleural calcification visible on X-ray was relatively rare, at about 0.2% in large radiological series, and that it usually followed haemothorax, pleurisy or empyema. Studies cited included bilateral calcification in 6.3% of New York talc miners (Siegal, 1943), 5% of Dresden asbestos workers (Jacob and Bohlig, 1955), and 11 of 31 Danish insulation workers (Frost, 1956). Selikoff (1965) found 150 cases among 1,117 New York insulators, 145 of them in the 393 with more than 20 years' exposure. Other reports showed that plaques and asbestosis often did not occur together. In the Finnish anthophyllite mining area, calcification was found in 9% of adults in one commune and 6.5% in a neighbouring one, compared with about 0.5 per thousand elsewhere in Finland, including among people who had not worked at the mine or mill. Asbestos dust was found in snow up to 27 km from the mine, and asbestos stones used locally in fireplaces and saunas were suggested as a source. A Malmö autopsy study found asbestos bodies in 18 of 34 mesothelioma cases and in 12 controls. The author concluded that asbestos plays an essential part in plaque formation, but that another, as yet unknown factor, possibly environmental, also appears to be involved.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.
Ovarian cancer and asbestos. J. Graham, R. Graham. 1967;1(2):115-28. PubMed · Publisher
Tissue response to intraperitoneal asbestos with preliminary report of acute toxicity of heart-treated asbestos in mice. J. Jagatic, M.E. Rubnitz, M.C. Godwin, et al. 1967;1(3):217-30. PubMed · Publisher

Abstract

Intraperitoneal asbestos not only produced fibrosis, but a special and peculiar type of fibrosis which was proliferative, granulomatous and invasive, and histologically similar to mesothelioma, although morphologic evidence of actual malignancy was not obtained. Further, asbestos fibers exposed to high temperature produced a high degree of toxicity in experimental animals; this resulted in a 60% mortality rate.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

Browse every journal in the library or the library by type of article, or return to medical research.

This page is provided for general informational purposes and does not constitute legal advice. Every asbestos case turns on its own facts, exposure history, diagnosis, deadlines, available evidence, and applicable law. Reviewing this page does not create an attorney-client relationship. For advice about your specific situation, call 833-4-ASBESTOS for a free case review.

Asbestos

Exposure

Look it up

By location

Cell types

Treatment & help

Cancers

Lung disease

Not sure

Trust claims

Lawsuits

Benefits

Guides & deadlines

Look up

History

Read & watch

The firm

Reach us