Pulmonary Ferruginous Bodies Studies on Their Origin

Our plain-English summary of Pulmonary Ferruginous Bodies Studies on Their Origin, by P. Gross, R.T.P. DeTreville, M. Haller (1970).

The study

• Authors: P. Gross, R.T.P. DeTreville, M. Haller
• Published: Pneumoconiosis: International Conference, Johannesburg (1970)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

The authors did animal experiments and examined ferruginous bodies (iron-coated fibers) taken from human and animal lungs. Rats and hamsters breathed three kinds of fibrous glass dust at an average of 100 mg per cubic meter for a year. Their lungs showed collections of dust-filled cells, with no destruction of the air sacs. Hamster lungs contained abundant ferruginous bodies. In a preliminary study, 10 rats and 10 hamsters had iron-free brake drum dust injected into the windpipe. X-ray diffraction of this dust had been negative for chrysotile. The tissue reaction resembled that to glass, without fibrosis, and many ferruginous bodies formed. Using electron diffraction, none of 28 ferruginous bodies from the lungs of 28 Pittsburgh city dwellers gave a chrysotile pattern. All 6 bodies from brake-dust-injected hamsters did, and the authors called these asbestos bodies. The human cores were crystalline. They could not be positively identified as amosite or crocidolite, but those minerals could not be ruled out either. The authors considered the failure to find chrysotile significant. They noted that examining more people, and more than one body per lung, might find asbestos 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: Animal experiments (inhalation and intratracheal injection in rats and hamsters) plus electron diffraction analysis of the cores of ferruginous bodies taken from human and hamster lungs
• Who was studied: 28 ferruginous bodies, one from each of 28 lungs of city dwellers from Pittsburgh. Rats and hamsters exposed to fibrous glass dust. 10 rats and 10 hamsters injected with brake drum dust, from which 6 hamster ferruginous bodies were analyzed.
• Exposure: Animals: three kinds of fibrous glass dust (uncoated, coated with a phenol-formaldehyde type resin, or coated with a starch binder), inhaled at an average of 100 mg per cubic meter for one year. Also iron-free brake drum dust, injected intratracheally: 2 x 10 mg for rats and 3 x 3.5 mg for hamsters. The brake drum dust consisted mainly of iron, a phenol-formaldehyde type resin, and forsterite, a mineral formed when chrysotile is heated.
• Main results:
  • In animals exposed to fibrous glass dust for one year, there was no destruction of alveoli (air sacs). The authors saw no differences among the three kinds of glass dust.
  • Abundant ferruginous bodies were found in the lungs of hamsters exposed to fibrous glass dust.
  • The iron-free brake drum dust was negative for chrysotile by X-ray diffraction.
  • In rats and hamsters injected with brake drum dust, the tissue reaction was similar to that seen with fibrous glass, with no fibrosis. The lungs contained many ferruginous bodies.
  • None of the 28 consecutive ferruginous bodies from the lungs of Pittsburgh city dwellers gave an electron diffraction pattern identifiable as chrysotile.
  • All 6 ferruginous bodies from hamster lungs injected with brake drum dust gave an electron diffraction pattern characteristic of chrysotile. The authors therefore called them asbestos bodies.
  • The cores of the human bodies gave a diffraction pattern, so the fibers had a crystalline structure. The pattern was not similar enough to known amosite or crocidolite samples to identify either positively, but these and possibly other asbestos minerals could not be excluded.
  • In the discussion, the author Gross said that asbestos bodies from known chrysotile workers, used as a control, gave an electron diffraction pattern very similar to that of natural chrysotile.
• The authors' conclusion: The authors concluded that chrysotile can be excluded as the central fiber in all the human ferruginous bodies examined to date. They considered the failure to find a chrysotile core in any of the 28 bodies significant.
• Limitations the authors state:
  • The brake drum dust experiment was a preliminary study using only a few animals.
  • Only one body per lung was examined. The authors said that examining bodies from more people, and more than one per lung, might identify asbestos fibers in the cores.
  • In the discussion, Gross said there was no information on whether chrysotile fibers deteriorate in the human lung. Gross did not know whether such deterioration explained why the human bodies failed to give a chrysotile pattern.

Topics

Medical terms in this study, explained in our Lexicon: Ferruginous body, X-Ray Diffraction (XRD), Chrysotile, Fibrosis, Asbestos Bodies, Crystalline, Amosite, Crocidolite.

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