A simple method for preparing ferruginous bodies for electron microscopic examination

Our plain-English summary of A simple method for preparing ferruginous bodies for electron microscopic examination, by A. Churg, N. Sakoda, M.L. Warnock (American Journal of Clinical Pathology, 1977).

The study

• Authors: A. Churg, N. Sakoda, M.L. Warnock
• Journal: American Journal of Clinical Pathology
• Published: 1977;68(4):513-7
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A new method of preparing ferruginous (asbestos) bodies for electron-optical examination is described. Pulmonary tissue is dissolved in bleach and the residue collected on a Millipore filter. The ferruginous bodies are localized by light microscopy, and a portion of the filter containing a body is cut out and mounted on a coated electron microscope grid. The filter is dissolved in acetone vapor in a condensation washer, leaving the bodies, as well as uncoated submicroscopic fibers, on the grid. This method can be used to obtain bodies from the lungs of individuals after all degress of asbestos exposure, but it is particularly useful when dealing with minimally exposed or non-exposed individuals whose lungs contain very few bodies. The procedure allows easy identification of body cores by electron diffraction or electron microprobe analysis.

In plain English

This article described a laboratory method, from the University of Chicago, for preparing ferruginous (asbestos) bodies from lung tissue so that their cores could be identified with an electron microscope. Lung tissue was dissolved in laundry bleach and the residue was collected on a Millipore filter. Bodies were located by light microscopy. Small pieces of filter holding them were mounted on electron microscope grids, and the filter was then dissolved in acetone vapor. Using the method, the authors analyzed by electron diffraction the cores of approximately 250 bodies from 20 individuals with various low degrees of asbestos exposure. Light microscopic counts in these lungs ranged from 40 to 1,000 bodies per gram of wet lung. Most bodies contained amphibole asbestos and a small number had chrysotile cores. Full results were to be reported elsewhere. The authors concluded the method was an improvement over earlier ones and technically easy. They noted that it still lost a substantial number of bodies and was not generally suitable for counting uncoated fibers. Control grids run without tissue showed contaminating single chrysotile fibrils and amorphous fibers.

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 paper describing a technique for preparing ferruginous bodies from lung tissue for electron microscopy, with a brief report of its use
• Who was studied: Lung tissue from 20 individuals with various low degrees of asbestos exposure (about 250 bodies analyzed); work done at the Department of Pathology, University of Chicago; dates of specimen collection not given
• Exposure: Various low degrees of asbestos exposure; light microscopic counts of 40 to 1,000 ferruginous bodies per gram of wet lung, most specimens 50 to 300 bodies per gram
• Main results:
  • Among the approximately 250 bodies from 20 low-exposure individuals, most bodies contained amphibole asbestos and a small number had chrysotile cores (details to be presented elsewhere)
  • The method allowed selection of bodies as small as 10 micrometres by light microscopy, smaller than those easily handled by micromanipulation
  • The chemical treatment appeared to make the iron-protein coat of the bodies more sensitive to vaporization by the electron beam than with KOH digestion, which helped expose cores of heavily coated bodies for diffraction
  • Uncoated amphiboles, chrysotile fibers in bundles, single chrysotile fibrils, amorphous fibers, clays and diatomaceous earth were found on grids, but some of these were contaminants
• The authors' conclusion: The authors concluded the method was an improvement over previously described methods: technically easy, requiring only inexpensive glassware, and reproducible from case to case once mastered
• Limitations the authors state:
  • The preparation still loses a substantial number of bodies, most likely during the condensation-washing step
  • The procedure is not generally applicable to counting uncoated fibers
  • Control grids prepared without tissue showed small numbers of single chrysotile fibrils and variable numbers of amorphous fibers, so background material must be interpreted with care
  • Many uncoated fibers are likely lost during processing

Topics

Medical terms in this study, explained in our Lexicon: Ferruginous Bodies, Acetone Vapor, Asbestos Exposure, Electron Microprobe Analysis.

Related studies

• Scanning electron microscopic examination of human asbestos bodies — M.L. Mace, T.L. McLemore, et al. (1980)
• Techniques for microscopic detection of asbestos bodies in lung tissue — P. Bradbury (2005)
• Fibrous dust particles and ferruginous bodies. Methods for quantitating them and some results from the lungs of city dwellers — P. Gross, J. Tuma, et al. (1970)
• Ferruginous bodies and pulmonary fibrosis in dead low to moderately exposed asbestos cement workers: histological examination — L.G. Johansson, M.P. Albin, et al. (1987)
• A rapid and simple method of extracting asbestos bodies from lung tissue by cytocentrifugation — A. Ehrlich, Y. Suzuki (1987)
• Environmental scanning electron microscopy technique to identify asbestos phases inside ferruginous bodies — A. Croce, M. Musa, et al. (2013)

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