Some new perspectives on the biological effects of asbestos

Our plain-English summary of Some new perspectives on the biological effects of asbestos, by Q. Rahman, P.N. Viswanathan, S.H. Zaidi (Environmental Research, 1977).

The study

• Authors: Q. Rahman, P.N. Viswanathan, S.H. Zaidi
• Journal: Environmental Research
• Published: 1977;14(3):487-98
• Type of article: Review
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 002249).

In plain English

This 1977 article from the Industrial Toxicology Research Center in Lucknow, India, was a review, not a new study. The authors summarized recent biochemical research on how asbestos harms the body. They drew heavily on their own center's earlier experiments in rats, guinea pigs, lung tissue preparations and red blood cells, along with work by others. In one study they described, rats given amosite or chrysotile into the windpipe had raised collagen and mucopolysaccharide in the lungs after 150 days, while anthophyllite caused no significant change. In laboratory tests, chrysotile dissolved fastest, inhibited lung enzymes the most and caused the most breakdown of red blood cells. Other animal studies they cited reported release of enzymes from lysosomes and changes in mitochondrial enzymes. The authors concluded that the varied effects of asbestos could be linked by a single biochemical mechanism. They also concluded that dissolution of the dust, which releases silicic acid, is likely an important cause of disease. They noted that the exact mechanisms still awaited explanation.

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: Review of recent biochemical investigations on the biological effects of asbestos, with the authors' proposed mechanism
• Who was studied: No new subjects. The review covers published and unpublished biochemical studies, many from the authors' own center in Lucknow, India, in rats, guinea pigs, cell and tissue preparations and red blood cells, plus some reported findings in asbestos workers.
• Exposure: Mainly amosite, anthophyllite and chrysotile asbestos dusts, given to animals by intratracheal injection or tested on tissues in vitro; silicic acid dissolved from the dusts
• Main results:
  • In a cited study of rat lungs 150 days after intratracheal injection (Rahman et al., 1975c), chrysotile and amosite raised collagen and mucopolysaccharide contents. Anthophyllite caused no significant change.
  • In cited in vitro work on rat lung homogenates, enzyme inhibition was at least qualitatively proportional to silica dissolution from the dusts. Chrysotile dissolved fastest and was the most inhibitory.
  • In cited studies of red blood cell damage (hemolysis) by various silicates, chrysotile, the most soluble, caused the most hemolysis.
  • In a cited study, contact with amosite in vitro did not affect lysosomal enzymes. Silicic acid, however, did disrupt them. The authors took this to mean that products dissolved from the dust cause the in vivo effect.
  • In cited rat lung studies (Beg et al., 1973), cytochrome oxidase and diaphorase activity increased significantly. Ca-activated and Mg-activated adenosine triphosphatase decreased markedly.
  • In cited guinea pig studies (Singh et al., 1975), mitochondrial enzymes cytochrome oxidase, malic dehydrogenase and diaphorase increased markedly.
  • In a cited study of guinea pigs injected with amosite (Viswanathan et al., 1973b), serum albumin decreased and total globulin increased at different stages.
• The authors' conclusion: The authors concluded that the diverse biological effects of asbestos could be interrelated and explained by a unified molecular mechanism. They also concluded that dissolution of the dust (silicic acid) is likely an important pathogenic factor.
• Limitations the authors state:
  • The authors stated that the exact biochemical mechanisms of asbestos effects on membranes still awaited elucidation.
  • The authors stated that further studies were needed to understand what their laboratory observations mean for asbestosis.
  • The authors noted that clinical data give only partial information on the biochemical changes.

Topics

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

Related studies

• Some biological properties of respirable iron ore dust — D. Keast, N.P. Sheppard, et al. (1987)
• Biochemical studies in infective amosite pneumoconiosis — A.K. Jaiswal (1981)
• Acute biological effects of intratracheally instilled titanium dioxide whiskers compared with nonfibrous titanium dioxide and amosite in rats — Y. Ishihara, H. Kyono, et al. (1999)
• Biological autoxidation. II. Cholesterol esters as inert barrier antioxidants. Self-assembly of porous membrane sacs. An hypothesis — S.H. Kon (1978)
• Biological effects of chrysotile after SO2 sorption. II. Effects on alveolar macrophages and red blood cells — M.C. Jaurand, J. Bignon, et al. (1978)
• Biological reactivity of PVC dust — R.J. Richards, R. Desai, et al. (1975)

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