Fibrous minerals in the lungs of mesothelioma patients: comparison between data on SEM, TEM, and personal interview information

Our plain-English summary of Fibrous minerals in the lungs of mesothelioma patients: comparison between data on SEM, TEM, and personal interview information, by T. Tuomi (American Journal of Industrial Medicine, 1992).

The study

• Author: T. Tuomi
• Journal: American Journal of Industrial Medicine
• Published: 1992;21(2):155-62
• Cited by: 34 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

To determine and compare the fiber types and size distributions in the lung tissue of mesothelioma patients in Finland, samples from 29 patients with known work history were analyzed with transmission electron microscopy (TEM) and X-ray microanalysis. Compared with the earlier results using scanning electron microscopy (SEM), the fiber concentrations were about three times as high and ranged from 0.1 million to 5,200 million fibers per gram of dry tissue. In 15 patients (52%), crocidolite/amosite were the dominating fiber types, representing more than 70% of all fibers. Anthophyllite asbestos was the most prevalent fiber type in eight patients (28%), and it was found in the samples of 13 patients (45%). One-half of the anthophyllite fibers were longer than 5 microns, whereas other fiber types were somewhat smaller.

In plain English

This Finnish study measured mineral fibers in lung tissue from 29 mesothelioma patients (27 men, two women; 28 pleural and one peritoneal mesothelioma) whose work histories were known. Samples were analyzed with transmission electron microscopy (TEM), and the results were compared with scanning electron microscopy (SEM) counts. TEM counts averaged three times the SEM counts and ranged from under 0.1 million to 5,200 million fibers per gram of dry tissue. Crocidolite and amosite, which were poorly distinguished by X-ray analysis and so were reported together, made up more than 70% of fibers in 15 patients (52%). Anthophyllite was found in 13 patients (45%) and was the most common type in eight (28%). Chrysotile was found in six patients and tremolite in five. The eight shipyard workers had 25 million to 3,300 million fibers per gram, 90 to 100% of them crocidolite and amosite. Half of the anthophyllite fibers were longer than 5 micrometres. The author concluded that anthophyllite, chrysotile and other silicate fibers, although commonly found together with other fiber types, cannot be excluded as causes of mesothelioma.

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.

What the study did and found

• Design: Descriptive case series: electron-microscopic analysis of fiber types and sizes in lung tissue, comparing TEM results with SEM results
• Who was studied: 29 Finnish mesothelioma patients from Helsinki University Central Hospital (28) and Tampere University Central Hospital (1), 1985-1988. There were 27 men and two women, with a mean age at diagnosis of 55 years (range 39-72). Of these, 28 had pleural mesothelioma and one peritoneal mesothelioma. Samples were 22 autopsy and seven biopsy.
• Exposure: Fibers retained in the lung: crocidolite/amosite (combined), anthophyllite, chrysotile, tremolite, other silicate fibers and other inorganic fibers. By work history, 10 patients worked in shipbuilding, insulation or asbestos spraying, 4 in construction, 10 in maintenance jobs, and 5 in occupations with a lower probability of asbestos exposure.
• Main results:
  • Across all 29 patients, TEM fiber counts were on average three times as high as SEM counts.
  • Across all 29 patients, TEM lung fiber concentrations ranged from less than 0.1 million to 5,200 million fibers per gram of dry tissue.
  • Using limits of 1 million fibers per gram (SEM) and 3 million fibers per gram (TEM), 20 patients (69%) exceeded the SEM limit and 22 patients (76%) exceeded the TEM limit.
  • Crocidolite/amosite was the predominant fiber type in 15 patients (52%), making up more than 70% of their total fiber burden.
  • Anthophyllite asbestos was the most prevalent fiber type in eight patients (28%) and was found in 13 patients (45%).
  • Chrysotile was detected in six patients (21%) and tremolite in five patients (17%).
  • In the eight patients who had worked in shipyards, lung fiber concentrations ranged from 25 million to 3,300 million fibers per gram of dry tissue (TEM), and crocidolite and amosite made up 90-100% of fibers counted.
  • In the five patients with no obvious asbestos exposure (hardware salesman, seamstress, editor, teacher, rubber worker), lung fiber concentrations were lower, and the main fiber types were anthophyllite or silicates.
  • Anthophyllite had the highest percentage of fibers longer than 5 micrometres (50%).
• The authors' conclusion: The author concluded that anthophyllite, chrysotile and other silicate fibers, although occupational exposure to them commonly occurs together with other fiber types, cannot be excluded as a cause of mesothelioma.
• Limitations the authors state:
  • Crocidolite and amosite were poorly distinguished in X-ray spectra, so their results were combined.
  • The non-asbestos silicate fibers were not identified mineralogically.
  • In some cases, SEM underestimated thin crocidolite and chrysotile fibers because of its lower resolution.
  • One biopsy sample (case 2) came from pleural plaque rather than lung tissue and gave a much lower fiber count than the autopsy sample.
  • Results from one electron microscopic method should be converted to or compared with another only cautiously.
  • When several fiber types were found and none clearly dominated, the contribution of each fiber type to causing the disease could not be determined.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Amosite, Anthophyllite, Crocidolite, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Work History, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Fibers Per Gram, Crocidolite, Amosite, Anthophyllite.

Related studies

• Pleural plaques and exposure to mineral fibres in a male urban necropsy population — A. Karjalainen, P.J. Karhunen, et al. (1994)
• Mineral phases and some reexamined characteristics of the International Union Against Cancer standard asbestos samples — N. Kohyama, Y. Shinohara, et al. (1996)
• Pulmonary mineral fibers after occupational and environmental exposure to asbestos in the Russian chrysotile industry — A. Tossavainen, E. Kovalevsky, et al. (2000)
• Does qualitative examination of Elongated Mineral Particles (EMP) recovered from human and animal lungs provide reliable information on their carcinogenic and other effects? — B.W. Case (2018)
• Lung mineral fibers of former miners and millers from Thetford-Mines and asbestos regions: a comparative study of fiber concentration and dimension — A. Nayebzadeh, A. Dufresne, et al. (2001)
• Rarity of mineral fibre pleurisy among persons exposed to Finnish anthophyllite and with low risk of mesothelioma — G. Hillerdal, A. Zitting, et al. (1984)

Browse more research in American Journal of Industrial Medicine, or return to medical research.