The effects of asbestos-cement dust inhalation on baboons

Our plain-English summary of The effects of asbestos-cement dust inhalation on baboons, by B. Goldstein, I. Webster, R.E. Rendall, et al (Environmental Research, 1978).

The study

• Authors: B. Goldstein, I. Webster, R.E. Rendall, M.I. Skikne
• Journal: Environmental Research
• Published: 1978;16(1-3):216-25
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy.

In plain English

In this animal experiment from South Africa, twelve male baboons were exposed in a chamber to dust collected from the extraction system of the hard-sheet cutting section of an asbestos-cement factory. The sheets were 12% asbestos (1.2% crocidolite and 10.8% chrysotile) and 88% Portland cement. Total dusting time ranged from 266 to 444 days. At a total dust concentration of 36 mg/m3, the mean count of fibres 5 to 100 micrometres long was 166 fibres/cm3 (standard deviation 26 fibres/cm3). The animals died, apparently of natural causes, 480 to 807 days after the start. All showed slight fibrous thickening of the pleura. Under the microscope, the walls of the smallest airways were thickened by fibrosis, and four animals also had foci of interstitial fibrosis. The changes were too variable to show a dose-response relationship. In two animals a bronchiole-alveolar carcinoma could not be excluded. None developed frank malignancy, which the authors said may reflect short survival. The authors concluded that the fibrosis closely resembled asbestosis and was most probably due to the asbestos, possibly modified by the cement.

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 inhalation experiment (baboons exposed to asbestos-cement dust in a chamber, with lung biopsies during the study and autopsy at death)
• Who was studied: Twelve male baboons of approximately 6 to 8 kg, caged in pairs in a 3 x 3 x 3 m dust exposure chamber at the National Research Institute for Occupational Diseases, Johannesburg, South Africa. The article does not give the dates of the experiment.
• Exposure: Coarse dust from the flannel bags of the extraction system in the hard-sheet cutting section of a large local asbestos-cement factory. The sheets were made of 12% asbestos (1.2% crocidolite and 10.8% chrysotile) and 88% Portland cement. Exposure sessions lasted 7 hours daily, 5 days per week.
• Main results:
  • Exposure level in the chamber: at a total gravimetric concentration of 36 mg/m3, the mean count of fibres 5 to 100 micrometres long was 166 fibres/cm3 (standard deviation 26 fibres/cm3).
  • The actual dusting periods for the animals ranged from 266 to 444 days.
  • The animals died, apparently of natural causes, 480 to 807 days after the experiment began.
  • On gross examination, the pleurae of all the animals showed slight fibrous thickening.
  • Under the microscope, the walls of the terminal air passages, from the terminal bronchioles outward, were thickened.
  • Four animals also had foci of interstitial fibrosis, and two showed a desquamative alveolitis.
  • Differences between animals, and between biopsy and autopsy material, were not clear enough to show a dose-response relationship.
  • Three animals showed an occasional focus of epithelial metaplasia in the terminal air passages.
  • In two further animals (exposed for 266 and 441 days) the changes were more extensive, and a bronchiole-alveolar carcinoma could not be excluded.
  • In all animals, asbestos fibres and dust particles were found in the areas of fibrosis.
  • Diffuse fibrosis of the pleura also occurred, with an occasional focus of mesothelial cell proliferation.
• The authors' conclusion: The authors concluded that dust from asbestos-cement sheet produced lung fibrosis that was very similar in appearance to asbestosis, and that it was most probably due to the asbestos in the dust, possibly modified by the cement.
• Limitations the authors state:
  • The dust used was coarser than dust that would normally be carried into the air.
  • Because individual animals reacted differently, no conclusions could be drawn from the slightly greater fibrosis seen at autopsy compared with biopsy.
  • The absence of frank malignancies may be due to the relatively short survival of the animals.
  • The effect of cement alone was not tested in this study; a separate experiment was in progress to examine it.

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestos-Cement.

Related studies

• Development of an animal model, techniques, and an exposure system to study the effects of asbestos cement dust inhalation — A.P. Wehner, G.E. Dagle, et al. (1978)
• A comparison of the effects of exposure of baboons to crocidolite and fibrous-glass dusts — B. Goldstein, R.E. Rendall, et al. (1983)
• Characterization of asbestos fibers in lungs and mesotheliomatous tissues of baboons following long-term inhalation — K. Hiroshima, Y. Murai, et al. (1993)
• Malignant mesothelioma induced in baboons by inhalation of amosite asbestos — I. Webster, B. Goldstein, et al. (1993)
• Characterization of the lower respiratory tract inflammation of nonsmoking individuals with interstitial lung disease associated with chronic inhalation of inorganic dusts — W.N. Rom, P.B. Bitterman, et al. (1987)
• Accumulation of mixed mineral dusts in the lungs of rats during chronic inhalation exposure — C.H. McMillan, A.D. Jones, et al. (1989)

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