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subject: Mesothelioma And The Binding Capacity And Cytotoxicity Of Tested Asbestos Mineral Fibres [print this page]


One interesting study is called, In vitro approaches for determining mechanisms of toxicity and carcinogenicity by asbestos in the gastrointestinal and respiratory tracts. By B T Mossman - Environ Health Perspect. 1983 November; 53: 155161. Here is an excerpt: Abstract Organ and cell cultures of gastrointestinal and tracheobronchial epithelium have been used to document both the interaction of asbestos with mucosal cells and the sequence of cellular events occurring after exposure of cells to fibers. The biological activity of various types of asbestos in vitro is related to surface charge, crystallization, and dimensional characteristics. These factors also influence adsorption of natural secretions and serum components to fibers, a process that ameliorates cytotoxicity. Although mechanistic studies at the cellular level are lacking using epithelial cells of the digestive tract, asbestos appears to elicit a constellation of morphologic and biochemical changes in tracheal epithelium that resemble effects of classical tumor promoters on target cells.

Another interesting study is called, Binding of environmental carcinogens to asbestos and mineral fibres. By G Harvey, M Pag, L Dumas - Br J Ind Med 1984;41:396-400. Here is an excerpt: Abstract - A rapid method has been developed for measuring the binding capacity of asbestos and other mineral fibres for environmental carcinogens. Benzo(alpha)pyrene (B(alpha)P), nitrosonornicotine (NNN), and N-acetyl-2-aminofluorene (NAAF) were assayed in the presence of Canadian grade 4T30 chrysotile, chrysotile A, amosite, crocidolite, glass microfibres, glasswool, attapulgite, and titanium dioxide. Chrysotile binds significantly more carcinogens than the other mineral fibres. This binding assay is reproducible with coefficients of variation of less than 8% and 6% respectively for inter and intra assay. The influence of pH was also studied, and there is good correlation between the carcinogen binding and the charge of the tested mineral fibres. The in vitro cytotoxicity on macrophage like cell line P388D1 and the haemolytic activity of various mineral fibres were also measured; a good correlation was found between the binding capacity and the cytotoxicity of tested mineral fibres on P388D1 cells. These results give some explanations for the reported synergism between exposure to asbestos and the smoking habits of workers.

Another interesting study is called, Production of reactive oxygen metabolites induced by asbestos fibres in human polymorphonuclear leucocytes. By M Hedenborg, M Klockars - J Clin Pathol 1987;40:1189-1193. Here is an excerpt: Abstract - The ability of quartz and various asbestos fibres to induce the production of reactive oxygen metabolites in human polymorphonuclear leucocytes was assessed. A chemiluminescence assay showed that the activation of polymorphonuclear leucocytes was induced in the following order of effect: quartz; chrysotile A; crocidolite; chrysotile B; amosite; and anthophyllite. Only slight chemiluminescence was produced by cells exposed to wollastonites and titanium dioxide. A positive correlation was seen between production of chemiluminescence and red cell haemolysis. Our results suggest that the potential of various environmental particles and mineral fibres to induce inflammation, fibrosis, and cancer of the lung could be related to their ability to induce inflammatory cells to produce reactive oxygen metabolites.

Another interesting study is called, Benign Asbestos Pleurisy by H. B. Eisenstadt, MD - JAMA. 1965;192(5):419-421. Here is an excerpt: THE classical picture of asbestosis has been divided into several stages.1 At first, there is a latent period of ten or more years during which asbestos bodies are formed around the asbestos fibers. During this time the patient is completely asymptomatic, and results of his chest x-ray are normal. This stage is followed by the gradual appearance of respiratory symptoms in the form of dyspnea, cough, expectoration, and wheezing; the roentgenologist finds bilateral pulmonary fibrosis. As the disease advances, systemic complaints are added, such as fatigue, malaise, weakness, anorexia, and weight loss. Finally, extensive destruction of lung tissue leads to respiratory and cardiac failure. It is well known that pleural abnormalities are commonly found in asbestosis. Most experts believe that they are associated only with advanced pulmonary disease; others describe them as secondary complications or even as coincidental lesions not directly connected with asbestos inhalation.

If you found any of these excerpts interesting, please read the studies in their entirety. We all owe a debt of gratitude to these researchers for their hard work.

by: Mont Wrobleski




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