Ferruginous bodies in sputum as an indication of exposure to airborne mineral fibers in the mesothelioma villages of Cappadocia

The counts of ferruginous bodies (pulmonary-coated mineral fibers) in sputum samples from inhabitants in each of the two agricultural villages of Karain and Tusk?y (Cappadocia, central Turkey) increased with subjects' age, whereas 94% of samples collected in the neighboring villages were free of ferruginous body. These findings are consistent with the previous hypothesis that the very high frequency of mesothelioma in Karain and Tusk?y was related to exposure to airborne mineral fibers of natural origin.     

Inhibition by phospholipids of haemolytic action of asbestos.

Haemolysis by asbestos fibres results from an increase in membrane permeability and not from rupture of red blood cells (RBC). The effect of chrysotile asbestos on RBC is at least partly, if not completely, attributable to lipid extraction and adsorption on to the fibres. This was suggested by the hyperbolic relationship between the haemolytic activity of chrysotile and the relative concentration of both chrysotile and RBC. Moreover, it was shown that pre-incubation of chrysotile with lipids, either as RBC membranes or with pure lipids in the form of liposomes, prevents haemolysis.     

Mesotheliomas in rats following inoculation with acid-leached chrysotile asbestos and other mineral fibres

The carcinogenicity of untreated UICC chrysotile A, of acid(oxalic and hydrochloric)-leached UICC chrysotile A, of crocidoliteand of JM 104 glass fibres has been studied by intrapleuralinjection into rats. This experiment, carried out on 304 animals,demonstrated that when more than 80% of the Mg had been leachedfrom chrysotile fibres by either hydrochloric or oxalic acid,the proportion of pleural mesotheliomas was either nil or dramaticallylower than that obtained with untreated chrysotile. The carcinogeniceffect of crocidolite was higher than that of 43.7% oxalic acid-leachedchrysotile. The proportion of mesotheliomas observed in animalsinjected with JM 104 glass fibres was similar to that in animalsinjected with fibres from which 63.8% had been leached withoxalic acid. These results indicate that with regard to theinduction of pleural carcinogenicity by chrysotile fibres, notonly size characteristics but also parameters such as chemicalcomposition and physicochemical properties must intervene.     

Effects of well-defined fibres on red blood cells and alveolar macrophages

The fibres used in this experiment were UICC asbestos fibres (chrysotile, amosite, crocidolite, either untreated or leached with oxalic acid), nemalite and glass fibres. Chrysotile was also treated with sulfur dioxide. Size distribution measurements by electron microscopic analysis, chemical analysis and measurement of specific surface area were performed. Haemolytic activity was studied in human red blood cells by kinetic analysis of the percentage of haemoglobin released; this generated information on the shape of the curve, the initial velocity of the haemolysis and the maximal haemolysis. The effect on rabbit alveolar macrophages was determined in vitro by the measurement of lactic dehydrogenase and beta-galactosidase released from alveolar macrophages cultured with the fibres. Amphiboles and chrysotile had opposite reactivities on red blood cells. Leaching did not change the shape of the curve with chrysotile whereas it modified that with amphiboles. The initial velocity decreased with leached chrysotile and increased with leached crocidolite or amosite. Maximal haemolysis was linearly dependent on the fibre concentration with amosite and crocidolite, but not with chrysotile or nemalite. The adsorption of sulfur dioxide onto chrysotile did not highly modify its haemolytic activity. In alveolar macrophages, chrysotile and leached amphiboles selectively released beta-galactosidase; and leached chrysotile and nemalite released both enzymes studied.     

Biological effects of chrysotile after SO2 sorption. II. Effects on alveolar macrophages and red blood cells.

An experimental study has been carried out using different biological and biochemical in vivo and in vitro tests for assessing the toxicity of natural UICC (A) chrysotile and SO2-sorbed UICC (A) chrysotile and for detecting a possible synergistic effect. For in vivo studies, rabbits received an intratracheal injection of chrysotile fibers suspended in physiological saline (PS). The control group received only PS; all animals were sacrificed after 68 hr. The alveolar free cells were harvested by pulmonary lavage. The results have shown that chrysotile induces a decrease in the free cell population but there was no significant difference in the number of viable cells or in the nature of cells harvested between the two chrysotile groups. Enzymatic activities of the alveolar macrophages from animals injected with SO2-sorbed chrysotile showed a significant increase of the enzymes LDH and acid phosphatases. The LDH increase could be related to the affinity of the enzyme regarding some chemical forms of SO2. In vitro studies using alveolar macrophages harvested by pulmonary lavage have shown no differences between the two chrysotile groups when cell viability and enzyme release were studied. The toxic effect was due to chrysotile fibers (decrease of 38% in cell viability and increase in cellular enzyme release when compared with control). When rabbit red blood cells were used, both natural and SO2 chrysotile fibers showed the same hemolytic activity. The failure to detect high differences between the two chrysotile groups may be related to the chemical form of sorbed SO2.     

Brca1 and Brca2 protein expression patterns in different tissues of murine origin

We have analyzed by immunohistochemistry Brca1 and Brca2 protein expression in mouse during embryonic development, in adult tissues, and during postnatal mammary gland development. Our observations confirm previous localization of Brca1 and Brca2 mRNA on frozen sections by in situ hybridization, and demonstrate that Brca1 and Brca2 proteins are expressed in rapidly proliferating cell types undergoing differentiation. These results imply that Brca1 and Brca2 proteins are involved in the process of proliferation and differentiation in multiple tissues, notably in the mammary gland during pregnancy and lactation.     

Asbestos-related occupational lung diseases. Role of the pneumology unit in screening and compensation

The application of new decrees concerning the protection of individuals against sanitary risks linked to the various possible expositions to asbestos dusts is leading to a growing involvement of pulmonologists in diagnosis procedures not only for active workers regularly examined via the occupational medicine healthcare system, but also for those who are no longer, the unemployed or retired previously exposed to asbestos fibres. The present chapter presents and comments the revised guidelines about the compensation procedures for occupational diseases, and provides useful recommendations for establishing the records leading to their medical assessment. It emphasises the importance of a close cooperation between pulmonologists and radiologists in order to avoid radiation overdosing, which could increase the risk of lung cancer, as much as possible.