[Cytogenetic indices for somatic mutagenesis in mammals exposed to chronic low-dose irradiation].

We used cytogenetic analysis in the studies of the biological effects of a radiation factor of natural and artificial origin (under conditions ofthe 30-km exclusion zone ofthe Chernobyl experimental landfills in Ukraine, Belarus and Russia). The studies have been performed on various types of mammals: domestic animals--cows, pigs, horses and rodents--root voles, the Af mouse line, and yellow necked field mouse, bank voles. We found significant changes in the level of MN and chromosomal aberrations in the animals that were exposed to the conditions of chronic low-dose radiation for a long time (bothin the habitat and upon exposure in the Chernobyl zone) regardless of the type of animal and nature of contamination.

[Effect of radio-ecological conditions in the ChNPP exclusion zone on morphofunctional state and responsiveness of organs and tissues of laboratory animals].

The state of hematopoietic, reproductive and endocrine systems of the organisms of male rats and their offspring in generations (F0-F1-F2) was studied, and the sensitivity of an organism to the action of carcinogen (Af mice) after a stay in the ChNPP exclusion zone was analyzed. It was ascertained that the most significant changes of the morphofunctional state of the animals were observed in the II generation (F2), which remained for a long period under the conditions of radioactive contamination. We have revealed an increased number of leukocytes, neutrophils, lymphocytes, and, especially, monocytes as against while the decrease in the number of erythrocytes and haemoglobin content; the decrease of thyroid function and cortical layer of the adrenals as opposed to while the increase in the relative weight of testes and their epididymides and the decrease in the number of spermatocytes and spermatozoa in the testis tissue. The exposure of Af mice in the exclusion zone increases the processes of mutagenesis and carcinogenesis, and changes the organism response to standardized action of chemical carcinogen. The increase in the exposure time of animals intensifies metabolic processes in a cell and increases their sensitivity to the action of xenobiotics.

[The influence of ecological factors of Polesky State Radioecological Reserve on spontaneous and chemically induced mutagenesis and tumor formation].

The cycle of researches of the influence of an exposion of mice of line Af in the conditions of the zone of Chernobyl disaster on spontaneous and chemically induced mutability, lung tumour (adenomas), morphological and functional condition of alveolar macrophages, and also genetic effects in natural populations wild rodents is executed. The increase in polychromatic frequency in mouse bone marrow, adenomas in lungs, and change of sensitivity of an organism to action mutagen and transgenerational transfer of genetic damages is shown.

[Dose-effect and time-effect characteristics in process of tumorigenesis under combined action of ionizing radiation and chemical carcinogen]. / Zavisimosti doza-éffekt i vremia-éffekt v protsesse opukholeobrazovaniia pri sochetannom deistvii ioniziruiushchego izlucheniia i khimicheskogo kantserogena.

Studying of dose and time dependences of frequency of adenomas appearing under the combined effect of radiation and urethane ingressed during different terms after irradiation has show that the frequency of tumours is determined both by radiation dose, and the time interval between irradiation and ingressing of cancerogenic substance. The data obtained show the period of preservation of the induced damages and non-linearity of the process of tumour-formation under the combined effect of radiation and toxic factors on the organism. The latter is necessary to be taken into account when forecasting the radiation risk under the real ecological conditions.

[The effect of dosage strength on the induction of chromosome aberrations and lung tumors in mice under the combined action of ionizing radiation and chemical substances]. / Vliianie moshchnosti dozy na induktsiiu khromosomnykh aberratsii i opukholei legkikh u myshei pri sochetannom deistvii ioniziruiushchego izlucheniia i khimicheskikh veshchestv.

In the experiment with combined influence of single or prolonged gamma irradiation (35 cGy) and chemical agents (urethanum, nitrogen oxide) on the induction of chromosome aberrations in bone marrow cells and lung tumor the effect of dose rate was studied. The frequency of chromosome aberrations increased with dose rate. Yet the correlation between the ratio of irreparable (stable) aberrations and dose rate was of inverse direction. The character of variations in lung adenoma frequency under multifactor influence in the case of prolonged irradiation (increase with dose rate decrease) supports the correlation between the level of stable aberrations in the pool of genetic lesions and the frequency of lung adenoma.

[Chromosome aberration induction in murine spermatocytes in joint exposure to radiation and sodium nitrite and nitrate]. / Indutsirovanie khromosomnykh aberratsii v spermatotsitakh myshei pri sochetannom vozdeistvii radiatsii i nitrita, nitrata natriia.

In studying the combined effect of single and fractionated exposure to gamma/neutron radiation (12.5-50 cGy) and sodium nitrite (100 mg/kg) and chronic irradiation with a mixture of radiation (25 cGy) and sodium nitrite, nitrate (10-100 mg/l) the synergistic effect was observed in inducing reciprocal translocations in mouse spermatocytes. The dose-response function of the reciprocal translocations occurrence in Af mouse spermatocytes was nonlinear; there was a "plateau" within the dose range from 25 to 50 cGy.