Electron microscopy applied to studies of the biological significance of defects in crocidolite asbestos

Our plain-English summary of Electron microscopy applied to studies of the biological significance of defects in crocidolite asbestos, by D. Crawford (Journal of Microscopy, 1980).

The study

• Author: D. Crawford
• Journal: Journal of Microscopy
• Published: 1980;120(Pt 2):181-92
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Transmission electron microscopy is used in an investigation of crocidolite asbestos associated with two biological systems. Control material is extremely defective and contains in particular an abundance of Wadsley defects, (100) planar faults, and pores. Fibres sectioned in lung tissue and fibres taken from in vitro exposure to blood serum show evidence of erosion by two mechanisms--preferential attack at (100) planar defects and general surface dissolution.

In plain English

This laboratory study used electron microscopy to examine the fine crystal structure of crocidolite asbestos fibers and how that structure changed in biological settings. The author examined thin cross-sections of untreated standard reference (U.I.C.C.) crocidolite, of fibers from the same batch placed in the lungs of male rats, and of fibers placed in normal human blood serum. The study did not look at disease. The untreated fibers were highly defective. They were bundles of smaller units with tiny pores, and they contained two kinds of structural faults, called (100) planar faults and Wadsley defects. Of all fibers examined, more than 40% contained (100) faults and 25% contained Wadsley defects. Fibers from both the lung and the serum showed effects the author interpreted as dissolution. One example was a cavity where a (100) fault met the surface of a fiber kept 14 days in serum. Another was a 'grey-layer' about 5-6 nm thick on fiber surfaces. Not all fibers showed erosion, and one untreated section also showed a grey layer. The author concluded that the defective state is important in studies of diseases popularly associated with crocidolite.

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 electron microscopy study (transmission and scanning electron microscopy) of crocidolite fibers, untreated and after exposure in rat lungs and in human blood serum in vitro
• Who was studied: U.I.C.C. reference crocidolite fibers: untreated control samples, fibers from the same batch placed in the lungs of male rats, and fibers placed in a sample of normal human blood serum. Numbers of rats and fibers are not given in readable form.
• Exposure: U.I.C.C. crocidolite; one serum example was examined after 14 days of immersion in blood serum
• Main results:
  • Pores were seen in all sections of fiber grains (untreated and exposed material)
  • Of all fibers examined, more than 40% contained (100) faults and 25% contained Wadsley defects
  • In a fiber taken from blood serum after 14 days, a cavity was seen where a (100) fault met the surface; such cavities were not seen in any control sample
  • A 'grey-layer' about 5-6 nm thick was commonly detected on fibers taken from the biological systems; the author interpreted it as a remnant of surface erosion
  • Fibers showed evidence of splitting (cleavage) at (100) faults but not at Wadsley defects
  • No biological effects clearly linked to Wadsley defects were observed
• The authors' conclusion: The author concluded that effects seen in crocidolite from lung and serum arose from dissolution, and that preferential attack at (100) planar faults emphasizes the importance of the defective state in studies of diseases popularly associated with crocidolite.
• Limitations the authors state:
  • Erosion was not observed in all fibers taken from the biological systems, and the author found this difficult to explain
  • One section of untreated control material also showed a grey layer; whether crocidolite dissolves in water was still being tested
  • The role of Wadsley defects was not determined
  • The author's structural model of a fibril boundary is speculative

Topics

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

Medical terms in this study, explained in our Lexicon: Crocidolite, Transmission Electron Microscopy (TEM).

Related studies

• The crocidolite fibres interaction with human mesothelial cells as investigated by combining electron microscopy, atomic force and scanning near-field optical microscopy — L. Andolfi, E. Trevisan, et al. (2013)
• The classification of asbestos fibres by scanning electron microscopy and computer-digitizing tablet — S.F. Platek, R.D. Riley, et al. (1992)
• Determination of mineral fibre in human lung tissue by light microscopy and transmission electron microscopy — A.J. Rogers (1984)
• An electron microscopy study of the effect of asbestos dust on the lung — J.M. Davis (1963)
• Final results from a 90-day quantitative inhalation toxicology study evaluating the dose-response and fate in the lung and pleura of chrysotile-containing brake dust compared to TiO2, chrysotile, crocidolite or amosite asbestos: Histopathological examination, confocal microscopy and collagen quantification of the lung and pleural cavity — D.M. Bernstein, B. Toth, et al. (2021)
• Evaluation of the dose-response and fate in the lung and pleura of chrysotile-containing brake dust compared to TiO2, chrysotile, crocidolite or amosite asbestos in a 90-day quantitative inhalation toxicology study - Interim results Part 2: Histopathological examination, Confocal microscopy and collagen quantification of the lung and pleural cavity — D.M. Bernstein, B. Toth, et al. (2020)

Browse more research in Journal of Microscopy, or return to medical research.