Fiber dimensions and aspect ratio of crocidolite, chrysotile and amosite particles detected in lung tissue specimens

Our plain-English summary of Fiber dimensions and aspect ratio of crocidolite, chrysotile and amosite particles detected in lung tissue specimens, by F.D. Pooley, N. Clark (Annals of the New York Academy of Sciences, 1979).

The study

• Authors: F.D. Pooley, N. Clark
• Journal: Annals of the New York Academy of Sciences
• Published: 1979;330:711-6
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy.

Abstract

Chrysotile, amosite and crocidolite fibers detected in autopsy tissue specimens from cases of mesothelioma and controls have been characterized by particle length, diameter and aspect ratio using a transmission electron microscope. The pooled information from such specimens reveals that the fibers of each mineral type detected in biological material have very different physical characteristics although in all samples fibers less than 5 microns in length are predominant by number while fibers over 25 microns in length are found very infrequently. Chrysotile fibers on average appear as the shortest fibers with the most fine diameter distribution, amosite fibers are on average the longest with the most coarse diameter distribution, crocidolite fibers on average have dimensions which are intermediate between both chrysotile and amosite. The percentage number of fibers of chrysotile, amosite and crocidolite detected with an aspect ratio less than or equal to 10 were 31.7%, 24.2% and 18.5% respectively.

In plain English

This study, part of an ongoing Cardiff project with the Medical Research Council Pneumoconiosis Research Unit, measured asbestos fibers from post-mortem lung tissue. The wider project includes asbestosis cases, but the article's summary says the measured specimens came from mesothelioma cases and controls. Numbers of people or fibers examined are not stated, and results were pooled, not compared by group. Fibers were measured with a transmission electron microscope and identified with an attached energy dispersive x-ray analysis system. Chrysotile fibers were the finest: 96.2% were under 0.125 microns wide and 49.3% were under 1 micron long. Amosite fibers were the coarsest and longest, and crocidolite fell in between. Most fibers of every type were under 5 microns long. An aspect ratio (length to width) of 10 or less applied to 31.7% of chrysotile, 24.2% of amosite and 18.5% of crocidolite fibers. For crocidolite and amosite, average width rose with length. The authors reported that preparation tests showed no major fiber changes apart from some extra fine chrysotile fibrils. They suggested experimental dusts should perhaps be prepared by air elutriation, not water sedimentation.

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: Laboratory analysis of fibers extracted from post-mortem lung tissue, part of an ongoing study. Fibers were measured by transmission electron microscopy and identified by energy dispersive x-ray analysis. Results were pooled across specimens.
• Who was studied: Post-mortem (autopsy) lung tissue (lung parenchyma). The article's summary describes the specimens characterized here as coming from mesothelioma cases and controls. The wider ongoing project also includes asbestosis cases. The specimens were collected and examined with the MRC Pneumoconiosis Research Unit at Llandough, Penarth, Wales. The number of cases, the number of fibers and the dates are not stated.
• Exposure: Chrysotile, amosite and crocidolite fibers found in lung tissue, measured for length, diameter and aspect ratio. For comparison, crocidolite and amosite samples prepared by water sedimentation and an airborne dust containing crocidolite were also measured. No occupational exposure information is given.
• Main results:
  • Most fibers of all three minerals were under 5 microns long. Fibers under 1 micron long made up 49.3% of chrysotile, 15.8% of crocidolite and 4.5% of amosite fibers (Table 1).
  • Chrysotile formed the finest fibers and amosite the coarsest. Fibers under 0.125 microns in diameter made up 96.2% of chrysotile, 61.9% of crocidolite and 21.3% of amosite fibers (Table 2). Amosite was the only mineral with a significant number of fibers wider than 0.5 microns.
  • The percentage of fibers with an aspect ratio of 10 or less was 31.7% for chrysotile, 24.2% for amosite and 18.5% for crocidolite.
  • The highest aspect ratio values reached were 400 for crocidolite, 200 for amosite and 700 for chrysotile.
  • For crocidolite and amosite, average fiber width increased with length. For chrysotile there was very little change in width with length.
  • The size data for an airborne crocidolite dust sample were closer to the data for crocidolite from lung tissue than were the data for water-sedimented samples.
• The authors' conclusion: The authors concluded that the size characteristics of the three minerals extracted from human tissue are very different, and that many fibers of all three have aspect ratios below 10 to 1. They suggested that dust for experimental purposes should perhaps be prepared by air elutriation rather than water sedimentation.
• Limitations the authors state:
  • The authors acknowledged that extensive preparation may alter fibers. Their tests showed no major changes except that some extra fine chrysotile fibrils were produced, which they said caused only very small statistical changes in the chrysotile size distribution.
  • The data are interim and are being updated as more specimens are examined, although the authors considered major changes unlikely.

Topics

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

Medical terms in this study, explained in our Lexicon: Fiber Dimensions, Aspect Ratio (Length-to-diameter ratio), Crocidolite, Chrysotile, Amosite, Autopsy, Mesothelioma.

Related studies

• High aspect ratio materials: role of surface chemistry vs. length in the historical "long and short amosite asbestos fibers" — M. Tomatis, F. Turci, et al. (2010)
• Dimensions of elongated mineral particles: a study of more than 570 fibers from more than 90 cases with implications for pathogenicity and classification as asbestiform vs. cleavage fragments — V.L. Roggli, C.L. Green (2019)
• Changes in numbers and dimensions of chrysotile asbestos fibers in lungs of rats following short-term exposure — V.L. Roggli, A.R. Brody (1984)
• Quantification of the pathological response and fate in the lung and pleura of chrysotile in combination with fine particles compared to amosite-asbestos following short-term inhalation exposure — D.M. Bernstein, R.A. Rogers, et al. (2011)
• The pathological response and fate in the lung and pleura of chrysotile in combination with fine particles compared to amosite asbestos following short-term inhalation exposure: interim results — D.M. Bernstein, R.A. Rogers, et al. (2010)
• Development of asbestos bodies on amosite, chrysotile and crocidolite fibres in guinea-pig lungs — S.K. Botham, P.F. Holt (1971)

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