Chemical characterization of uncoated asbestos fibers from the lungs of asbestos workers by electron microprobe analysis

Our plain-English summary of Chemical characterization of uncoated asbestos fibers from the lungs of asbestos workers by electron microprobe analysis, by A.M. Langer, I.B. Rubin, I.J. Selikoff, et al (The Journal of Histochemistry and Cytochemistry, 1972).

The study

• Authors: A.M. Langer, I.B. Rubin, I.J. Selikoff, F.D. Pooley
• Journal: The Journal of Histochemistry and Cytochemistry
• Published: 1972;20(9):735-40
• Cited by: 39 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Lung tissues have been obtained from workmen with defined asbestos fiber exposure. These tissues have been prepared by the carbon extraction technique and examined with the electron microprobe analyzer. The uncoated fibers present in these specimens have been chemically characterized and compared with standard reference asbestos samples. The bulk chemistry of the fibers observed in lung tissues is similar to that of the reference fibers so that identification may be made. However, a statistical analysis of the measured emission characteristics from anthophyllite and amosite indicates that some magnesium loss has taken place. This loss appears to correlate with the magnesium content of the fibers. A slight iron increase was also noted in the same fibers, probably related to an incipient asbestos body formation.

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

In plain English

This laboratory study examined whether asbestos fibers with no visible coating in workers' lungs had changed chemically. Lung tissue came from people who had worked in the regions where UICC standard reference fibers were mined, including mines in Finland and South Africa. The authors reported that no case involved mixed fiber exposure. Tissue sections were prepared by a carbon extraction technique, and the uncoated fibers were analyzed with an electron microprobe and compared with UICC reference fibers. In all, 104 tissue fibers were analyzed: 27 anthophyllite, 25 amosite and 52 crocidolite. The lung fibers remained chemically identifiable as their fiber type. Compared with reference fibers, iron was higher in all three types, and magnesium was lower in anthophyllite and amosite. Crocidolite showed no significant difference in magnesium. The authors concluded that a detectable, statistically significant chemical change had occurred, and suggested the iron gain may reflect an early coating. They noted that their sample was limited and that how long the fibers had been in the lungs was unknown.

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 analytical study: chemical analysis of uncoated asbestos fibers in human lung tissue by electron microprobe, compared with UICC standard reference asbestos samples
• Who was studied: Lung tissue specimens (paraffin-embedded unstained sections) from individuals who had worked in the regions where the UICC standard reference fibers were mined, including mines in Finland and South Africa; the number of individuals is not stated
• Exposure: Single fiber-type exposures to anthophyllite, amosite or crocidolite (no mixed fiber exposure in any case); exposure doses not given
• Main results:
  • 104 fibers from lung tissue were analyzed: 27 from the anthophyllite worker's lung, 25 from the amosite worker's lung and 52 from the crocidolite worker's lung
  • Fibers from lung tissue remained chemically identifiable as anthophyllite, amosite and crocidolite respectively
  • Iron was increased in all fibers from tissues, and magnesium was decreased for anthophyllite and amosite, compared with reference fibers
  • Anthophyllite (30 UICC vs 27 worker analyses): iron standard ratio 18.8 ± 2.7 (UICC) vs 23.2 ± 4.3 (worker), P less than 0.001; magnesium standard ratio 44.6 ± 1.4 (UICC) vs 41.4 ± 1.5 (worker), P much less than 0.001
  • Amosite (26 UICC vs 25 worker analyses): iron standard ratio 68.4 ± 1.5 (UICC) vs 69.9 ± 2.3 (worker), P between 0.02 and 0.01; magnesium standard ratio 25.2 ± 2.3 (UICC) vs 20.0 ± 4.7 (worker), P less than 0.001
  • Crocidolite (21 UICC vs 25 worker analyses): iron standard ratio 63.8 ± 1.7 (UICC) vs 66.4 ± 4.8 (worker), P between 0.05 and 0.02; magnesium standard ratio 9.4 ± 2.3 (UICC) vs 9.7 ± 5.0 (worker), P between 0.70 and 0.60
  • No significant difference in magnesium content was found between crocidolite fibers in tissue and crocidolite reference fibers
  • Crocidolite tissue fibers analyzed with sodium set in the third spectrometer varied widely. Every fiber lying outside a 5% emission value from the crocidolite field was coated, lay next to many other fibers, or was associated with a large amount of fibrotic tissue
  • No variation in fiber chemistry was related to fiber size
  • The magnesium loss from fibers in lung tissue appeared to follow the order anthophyllite greater than amosite greater than crocidolite
  • The authors suggested that the iron gain may reflect an incipient coating not readily visible at normal low magnification
• The authors' conclusion: The authors concluded that the chemistry of uncoated asbestos fibers in asbestos workers' lungs can be compared with the standard reference fibers, but that a detectable, statistically significant chemical change was observable
• Limitations the authors state:
  • The sample of fibers examined was limited, so small differences in fiber chemistry would not be evident
  • How long the fibers had been in the body was unknown in each case
  • Analysis was restricted to fibers easily resolvable with the microprobe, those greater than 0.3 in thickness (the unit symbol is lost in the scanned text)
  • Fibers had to be analyzed near the limits of the microprobe's resolution, making it difficult to choose fibers completely free of cellular debris and ash
  • Some particles may be lost during the ashing step of tissue preparation
  • It is not known whether the magnesium removed from fibers in the body has any biological significance

Topics

Medical terms in this study, explained in our Lexicon: Electron Microprobe Analysis, Anthophyllite, Amosite, Asbestos Bodies.

Related studies

• Chemical characterization of asbestos body cores by electron microprobe analysis — A.M. Langer, I.B. Rubin, et al. (1972)
• Elemental analysis of asbestos fibers by means of electron probe techniques — I.A. Rubin, C.J. Maggiore (1974)
• The identification of asbestos dust with an electron microscope microprobe analyser — F.D. Pooley (1975)
• A comparison of the ferruginous body and uncoated fiber content in the lungs of former asbestos workers — R.F. Dodson, M.G. Williams, et al. (1985)
• Beryllium detection in human lung tissue using electron probe X-ray microanalysis — K.J. Butnor, T.A. Sporn, et al. (2003)
• Electron microscope characteristics of inhaled chrysotile asbestos fibre — F.D. Pooley (1972)

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