Chemical characterization of asbestos body cores by electron microprobe analysis

Our plain-English summary of Chemical characterization of asbestos body cores by electron microprobe analysis, by A.M. Langer, I.B. Rubin, I.J. Selikoff (The Journal of Histochemistry and Cytochemistry, 1972).

The study

• Authors: A.M. Langer, I.B. Rubin, I.J. Selikoff
• Journal: The Journal of Histochemistry and Cytochemistry
• Published: 1972;20(9):723-34
• Cited by: 62 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Inhalation of asbestos may be associated with increased risk of developing malignant neoplasms. Some of the fibers become coated in the lung, resulting in “asbestos bodies.” The occurrence of structures with the appearance of asbestos bodies in the lungs of urban dwellers the world over, individuals with no known exposure to these mineral fibers, has raised the question of whether the community at large may also have increased risk of neoplasia as the result of chance environmental asbestos exposure. Since other fibrous materials may also sometimes become so coated, epidemiology evaluation of the presence of asbestos bodies has been hampered by difficulties in obtaining absolute identification of the cores of the bodies found. Five fibrous silicates, consisting of four amphiboles (amosite, anthophyllite, crocidolite and tremolite) and one serpentine (chrysotile), constitute the asbestos mineral group. Chemically, they are diverse enough for unique identification. The electron microprobe analyzer permits microchemical analysis of particles in the sublight microscopic size range. Analysis of asbestos body cores requires particle selection, extraction from tissue matrix, a suitable conducting substrate, proper coating material, selection of optimal instrumental operating conditions and comparison of unknown cores with known fiber standards. In this investigation, asbestos body cores have been analyzed from tissues obtained from occupationally exposed individuals (known fiber exposure), laboratory animals (known exposure) and individuals with no known occupational exposure. Cores of bodies have been analyzed as amosite, chrysotile, chemically degraded chrysotile and cores of undetermined nature. Amosite fibers as cores of asbestos bodies show no marked chemical degradation even after prolonged biologic residence, whereas chrysotile asbestos cores are markedly degraded. Cores of asbestos bodies from the general population, from individuals with no known exposure, may consist of degraded chrysotile, synthetic silicate fibers and, in some cases, amphibole asbestos.

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

In plain English

This laboratory study tested whether an electron microprobe could chemically identify the fiber at the core of asbestos bodies, the iron-coated fibers seen in lung tissue. Reference samples of five asbestos types fell in clearly defined areas of iron, silicon and magnesium signals. In 457 analyses of 35 asbestos bodies from a deceased worker at a factory using amosite, readings ranged from amosite toward the iron end of the scale depending on coating thickness. The authors related this spread to the coating and reported no marked chemical degradation of the amosite cores, although his last exposure was almost 10 years before death. Bodies from a hamster injected with chrysotile 651 days earlier showed marked magnesium leaching, and those from a Canadian chrysotile worker showed a similar pattern. In 50 analyses from the New York City general population, unaltered chrysotile was not demonstrated in any case. Some silica-rich fibers could have been degraded chrysotile or fibrous glass, and some analyses indicated amphibole cores. The authors noted that picking bodies under a light microscope selected only large ones, which tends to exclude chrysotile.

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 methods study using electron microprobe analysis of asbestos body cores taken from human and animal lung tissue
• Who was studied: Lung tissue from occupationally exposed people (a deceased worker at a factory using amosite; a Canadian chrysotile worker), one laboratory hamster, and people in the New York City general population with no known occupational exposure
• Exposure: Amosite (factory making insulation materials); chrysotile (Canadian chrysotile worker, and a hamster given chrysotile into the windpipe); no known exposure (general population)
• Main results:
  • Reference fibers of the five asbestos types (amosite, anthophyllite, crocidolite, tremolite, chrysotile) fell in clearly defined areas of their iron, silicon and magnesium signals
  • Amosite factory worker (457 analyses of 35 bodies): readings ranged from the amosite composition to the iron end of the scale
  • Amosite factory worker: where a reading fell depended on how thick the coating on the body was
  • Amosite factory worker: as coating thickness increased, successful core analysis became less likely
  • Amosite factory worker: amosite fibers were still present in the body cores although the last exposure was almost 10 years before death
  • Amosite factory worker: the amosite fibers appeared to have undergone no marked chemical degradation in the body
  • Hamster given chrysotile 651 days before sacrifice (20 asbestos bodies analyzed): many exposed fibers showed marked magnesium leaching
  • Canadian chrysotile worker (12 analyses): the results showed a distribution like the hamster's, and thinner fibers gave lower magnesium values than thicker ones
  • New York City general population (50 analyses): unaltered chrysotile was not demonstrated in any case
  • New York City general population: some silica-rich fibers could be interpreted as chemically degraded chrysotile or fibrous glass
  • New York City general population: some analyses indicated an amphibole core; calcium and sodium analyses showed only two may have been amosite and none crocidolite
• The authors' conclusion: The authors concluded that, unlike amosite, chrysotile undergoes marked chemical degradation in the body, losing magnesium
• Limitations the authors state:
  • The authors stated that the meaning and significance of the general-population observations are limited
  • Selecting bodies by micromanipulation under a light microscope picked only larger particles, which the authors said tends to exclude chrysotile
  • The coating around the fiber interferes with analysis of the core
  • The authors described micromanipulation as generally unsuitable, citing among other reasons the excessive time it requires

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Body Formation, Electron Microprobe Analysis, Neoplasm, Asbestos Bodies, Mineral Fiber, Asbestos Exposure, Epidemiology, Silicate.

Related studies

• Chemical characterization of uncoated asbestos fibers from the lungs of asbestos workers by electron microprobe analysis — A.M. Langer, I.B. Rubin, et al. (1972)
• Pulmonary asbestos body counts and electron probe analysis of asbestos body cores in patients with mesothelioma: a study of 25 cases — V.L. Roggli, M.H. McGavran, et al. (1982)
• The identification of asbestos dust with an electron microscope microprobe analyser — F.D. Pooley (1975)
• Beryllium detection in human lung tissue using electron probe X-ray microanalysis — K.J. Butnor, T.A. Sporn, et al. (2003)
• Elemental analysis of asbestos fibers by means of electron probe techniques — I.A. Rubin, C.J. Maggiore (1974)
• Oxygen incineration and electron microscope x-ray microanalysis of mineral particles in biological tissues — W.J. Henderson, C. Melville-Jones, et al. (1978)

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