[Experimental basis for possible tumors induction in descendants after placental transmission of chrysotile asbestos fibers].

Experiments on white outbred rats helped to establish placental transmission of chrysotile asbestos fibers from mother to fetus with reliable increased incidence of neoplasma in first generation, mainly of respiratory malignancies. Chronic exposure to chrysotile asbestos damaged peripheral lymphocytes and did not affect red bone marrow. Extrapolating the experimental data on placental transmission of chrysotile asbestos to children requires epidemiologic research.

[Micronucleus test as a short-term assay for detecting the potential carcinogenicity of different groups of chemical compounds]. / Mikroiadernyi test kak kratkosrochnyi metod vyiavleniia potentsial'noi onkogennosti razlichnykh grupp khimicheskikh veshchestv.

Certain theoretical aspects of the method, the normal level of micronuclei in polychromatic erythrocytes of bone marrow cells in different animals species, the data obtained for the different types of chemical compounds are analyzed as well as the possibility of obtaining false-negative and false-positive results. This method is found to be very promising and needs further development in the near future.

[Effect of carcinogenic substances on bone marrow cells in CBA mice]. / Vliianie nekotorykh kantserogennykh veshchestv na kletki kostnogo mozga u myshei CBA.

The effect of some carcinogenic and non-carcinogenic agents on the content of CFUs and frequency of micronuclei (Howell-Jolly corps) in polychromatic erythrocytes of bone marrow cells was studied in CBA mice. Benzene administration decreased the content of CFUs in bone marrow cells, but this effect is considered to be rather a sign of its hematotropic than carcinogenic action. Changes in the CFUs amount induced by chrysotile-asbestos and quartz DQ-12 action were insignificant. All investigated carcinogenic agents (benz(a)pyrene, asbestos and benzene) significantly increased the number of micronuclei in polychromatic erythrocytes of bone marrow in mice.

[The influence of "rigidity" and structure of fibrous dust on their biological activity]. / Vliianie "zhestkosti" i struktury voloknistykh pylei na ikh biologicheskoe deistvie.

The authors represent experimental data on cytotoxic, fibrogenic and mutagenic effects of fibrous dusts--"soft" pulp fibers and "stiff" ones (chrysotile-asbestos, carbon, basalt and fiber glass) in comparison with the nonfibrous analogs (antigorit, quartz DQ-12 and others). Viability of peritoneal macrophages was depressed more dramatically by "stiff" fibers vs. the "soft" ones. Mutagenic activity was associated with the "stiffness" degree of the dust particles. When compared to fibrous chemical dusts, nonfibrous ones appeared inert in micronuclear test.

[Modified effect of dust and chemical mutagens under the influence of vibration]. / Modifikatsionnyi éffekt pylevogo i khimicheskikh mutagenov pod vozdeistviem vibratsii.

The impact of transport vibration on the mutagenic effect (ME) of asbestos, benzo(a)pyrene (BaP), benzene, ortho-aminotoluene, and quinoline was studied. There was a decrease in ME of all the substances when they influenced erythrocytes simultaneously with 24-hour vibration. Decreased ME of BaP was seen during 2-month vibration, and ME increased during 3-day vibration.

[Mutagenic effects of asbestos modified by association with ethanol, coffee and tobacco tar]. / Modifikatsiia mutagennogo deistviia asbesta pri sochetanii s étanolom, kofe i kuritel'noi smoloi.

The study covered possible modification of mutagenic action of asbestos in combination with widespread agents--ethanol, coffee extractive and fumigating resin. Such modifying effects as antagonism, synergism were revealed as well as an independent action. An attempt was made to extrapolate the obtained data to human exposure to asbestos.

Possibility of inducing glandular stomach cancer in rats exposed to asbestos.

The possibility of glandular stomach cancer being induced was studied in 75 random bred white rats exposed to chrysotile asbestos. A perforated polyethylene capsule containing 100 mg asbestos and filler (beef fat and natural wax mixture 1:1) was introduced in an artificial bag placed on the greater curvature of the stomach. A capsule containing filler only was introduced in a similar way in 40 control rats. In the following 25 months, 18 tumors of the stomach and abdominal cavity were found in the rats treated with asbestos (eight adenomas, two adenocarcinomas, one carcinosarcoma, one forestomach cancer, one intestinal adenocarcinoma, two peritoneal mesotheliomas, and three abdominal lymphoreticulosarcomas.) Among the control rats no such tumors were found. The results of the experiment are discussed in connection with epidemiological data on stomach cancer in asbestos workers.

[Comparative carcinogenic properties of basalt fiber and chrysotile-asbestos]. / Sravnitel'naia onkogennost' bazal' tovykh volokon i khrizotil-asbesta.

In order to eliminate asbestos adverse effect on workers' health it was necessary to use mineral rayon, primarily basalt fibre, instead of asbestos. During a chronic experiment on animals the oncogenicity of 2 kinds of basalt fibre was studied compared to chrysotile asbestos. The dust dose of 25 mg was twice administered by intraperitonial route. All types of dust induced the onset of intraperitonial mesotheliomas but neoplasm rates were significantly lower in the groups exposed to basalt fibre. There was no credible data on the differences between the groups exposed to various types of basalt fibre. Since the latter produced some oncogenic effect, it was necessary to develop a complex of antidust measures, fully corresponding to the measures adopted for carcinogenic dusts.

[The oncogenic action of nonfibrous mineral dusts]. / Ob onkogennom deistvii nekotorykh nevoloknistykh mineral'nykh pylei.

Nonfibrous mineral dusts antigorite, basalt, cement, zeolite-klinoptilolite and gamma-alumina were tested for carcinogenic activity in rat experiments. Intraperitoneal injections of zeolite-klinoptilolite and gamma-alumina led to development of peritoneal mesotheliomas, whereas antigorite and cement had no carcinogenic potential. There is no differences in physicochemical and chemical properties between carcinogenically active and inactive nonfibrous dusts. A new class of carcinogenic substances is defined including basalt, zeolite-klinoptilolite and quartz which belong to nonfibrous mineral dusts.

[Hygienic aspects of the production of asbestos substitutes]. / Gigienicheskie aspekty proizvodstva zamenitelei asbesta.

Due to the high level aggressiveness of asbestos, more attempts have been made in the recent years to replace asbestos by other artificial mineral fibres. In this connection, the labour conditions were studied in the basalt and carbon fibres processing sites. The major occupational hazards of these sites included basalt and carbon fibres dusts, heating microclimate in some working zones and physical overload. An intratracheal experiment revealed a lower degree of fibrinogenicity of the basalt and carbon fibres as compared to chrysotile asbestos. The number of the induced mesothelioma in the intraperitoneal introduction of basalt and carbon fibres was markedly lower than in case with chrysotile asbestos. Hygienically, asbestos should be replaced wherever possible, and the dust control measures should by no means be inferior to those with asbestos.