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L N Pylev

Publications and source records attributed to L N Pylev.

86 records · Page 5Linked to original sources
PubMedDate not supplied

[The electric properties of fiber surface and the toxicity of asbestos].

Thermal treatment, autoclaving and their combination yielded 3 samples of chrysotile-asbestos. With these, as compared with parent Type PRZh-1-50 Bazhenov chrysotile, the structure of fibers deteriorated and the number of negative discharges increased in the first two samples; the superficial structure substantially increased and the number of positive centers greatly decreased in the third sample. The ratio of positive to negative centers was less in all treated samples than that in the parent one, it decreased particularly during combined treatment. In this sample, hemolytic and mutagenic activity and cytotoxicity were substantially decreased; carcinogenic activity was greatly decreased (by 4 times) (as shown by the pleural mesothelioma indication test during intrapleural administration to rats). Thermal treatment and autoclaving insignificantly lowered the hemolytic activity and mutagenicity; carcinogenicity of these samples was much less (by 2.3 and 2 times) than that of parent chrysotile.

Animals↗
PubMedDate not supplied

[Carcinogenic danger of zeolite from Kholinsk].

The carcinogenic activity of the enterosorbent optisorb (pure zeolite) and the biologically active food additive litovite [zeolite and rye brans (1:1)] based on zeolite-clinoptololite from the Kholinsk deposit was studied. The intrapleural three-fold administration of optisorb (20 mg x 3) to rats and the inclusion of optisorb (5% of the feed) and litovite (5 and 0.06%) into the feed showed that these agents had no carcinogenic activity.

Carcinogenicity Tests↗
PubMedDate not supplied

[Insignificant carcinogenicity of chrysotile asbestos of the Ak-Dovurak deposits in Russia and its possible links].

Thrice intrapleural injection of 20 mg of dust of the chrysotile from the Ak-Dovurak deposit caused pleural mesothelioma in 10.7% of the rats, which was significantly less than that upon exposure to the chrysotiles from other deposits and amphiboles. The reason for the less carcinogenicity of this chrysotile is the structural features of the surface of its fibrils, namely, its high homogeneity and hence the lack of sites at which the electrically charged centers may be located.

Animals↗
PubMedDate not supplied

[Characterization of the biological properties of acid-treated chrysotile-asbestos fibers].

Boiling of chrysotile of the textile brand PRZh1-50 in concentrated hydrochloric acid for 10, 15, and 20 minutes gave rise to three chrysotile-asbestos samples. The content of MgO decreased from to 24, 19, and 9%, respectively. As compared with the baseline values, the number and force of positively charged electrical centers were less in the samples containing 24 and 19% MgO and more in the sample having 9% MgO; the negatively charged centers were present in the former two samples and absent in the third one. When the samples were intrapleurally administered to rats, their hemolytic activity, induction of active oxygen radicals, mutagenic activity (micronuclear test using murine bone marrow cells), and the frequency of mesotheliomas were less in the treated samples than in the baseline ones; but there were no differences between the treated samples. Thus, the altered physicochemical properties of the fibrillar surface of asbestos diminished its biological aggressiveness; however, increased treatment rates failed to lead to its further decrease. There was no relationship of the biological properties to the number and force of electric charges of the surface.

Acids↗