[The alterations in profiles of RAPD- and of ISSR-markers in progeny of the single gamma-irradiated mice of BALB/c strain].

Molecular-genetic effects in the offspring of BALB/c male mice exposed to single radiation doses of 1, 2 and 3 Gy were studied. Induced genetic variability was studied using such methods as assessment of variation RAPD- and ISSR-profiles. Comparative analysis of genetic radiosensitivity of stem spermatogonia and of spermatids is presented in the work. The frequency of changes in the patterns of the offsprings of irradiated mice was significantly different from the analogous parameters in the offsprings of the control group already at a dose of 1 Gy. Comparative analysis of genetic radiosensitivity at different stages of spermatogenesis revealed the similar sensitivity of spermatogonia and of spermatids at 1 and 3 Gy and a higer sensitivity of spematogonia at 2 Gy.

[Genetic consequences of an increased radiation background at mouse-like rodents].

The frequency of genetic disturbances in germ-line and in somatic cells was studied in animals caught in radionuclide-cotaminated areas within the 30-km Chernobyl NPP zone as well as in model experiments in laboratory mice exposed to chronic external gamma-radiation or to the internal action of incorporated radionuclides (131I, 137Cs, 238Pu). The results of genetic and of cytologic analysis of germ-line and somatic cells in the caught or exposed house mice and in laboratory mice after incorporation of radionuclides are presented. An estimation of relative genetic efficiency of the most harmful radionuclides was made.

[The influence of chronic and of acute irradiation on the polymorphism of RAPD-markers in offspring for irradiated mice].

On mice lines BALB/c and CBA/lac was performed the study of molecular-genetics effects in mice progeny after the chronic (dose rate -0.0017 Gy/day, total dose -0.36 Gy) and acute (dose range 1-3 Gy) exposure of y-radiation on the parents. For variability analysis was used technique of amplification DNA with series of random primers (RAPD-assay). Random primers were used as single primer and in mixture of ones. In this work were held the comparative analysis of the genetic radiosensitivity for stem spermatogonia and spermatides. After the acute exposure the dose dependence for levels of polymorphism of RAPD-markers were obtained. After the chronic irradiation, significant differences from control group were obtained only by use primers mixture M1. Comparative analysis of the genetic radiosensitivity of different stages of mice spermatogenesis are display is similar sensitivity of stem spermatogonia and spermatides after doses of irradiation 1 Gy and 3 Gy. Indicated that after irradiation by dose 2 Gy, spermatogonia are more sensitivity than spermatides.

Chemical protection against genetic effect of radiation in male mice.

A study was made of the protective effect of some radioprotective agents against dominant lethal mutations (DLM) in postspermatogonial stages and reciprocal translocations (RT) in spermatogonia induced by gamma-radiation. Among the radioprotective agents used, cystaphos, a combination of cystamine and 5-MOT and a mixture of 6 components proved to be most effective against DLM, and cystaphos, gammaphos and cystamine combined with 5-MOT proved effective against RT. The degree of radioprotective efficacy was relatively low. The efficacy of cystamine in protecting against RT was higher with exposure of gonocytes of 18.5-day embryos than spermatogonia of pubertal animals. The degree of the radioprotective effect varied depending on the stage of spermatogenesis, and, in all cases, it was lower than that observed in studies of protection against lethal effects of ionizing radiation.

Genetic disorders in house mouse germ cells after the Chernobyl catastrophe.

Genetic effects were studied in house mice caught from 1986 to 1994 in regions polluted by radionuclides as a result of the Chernobyl disaster. The dose rates of gamma-radiation on the soil surface ranged from 0.0002 to 2 mGy/h. The frequency of reciprocal translocations in mouse spermatocytes was relatively low, but increased with the dose rate. Embryo mortality was increased only in the progeny of male mice in males caught in 1987 in the area with maximal contamination. The frequency of mice heterozygous for recessive lethal mutations decreased with time after the accident.

Genetic effect of chronic exposure of male mice to gamma-rays.

The frequency of reciprocal translocations (RT) in mouse spermatogonia induced by gamma-rays at doses of 1.5-4.5 Gy and dose rates of 2.7 X 10(-6), 5.8 X 10(-6), 9.4 X 10(-5) and 4.5 Gy/min was studied. At all dose rates there was a linear increase in the RT frequency with increasing dose. At a dose rate of 9.4 X 10(-5) Gy/min, the RT frequency was on average 10 times lower than that for a single acute dose rate of 4.5 Gy/min. Further dose rate reduction did not result in a decrease in the RT yield, and at the lowest dose rate of 2.7 X 10(-6) Gy/min and a dose of 3.0 Gy the RT frequency was higher than at dose rates of 5.8 X 10(-6) and 9.4 X 10(-5) Gy/min and the same dose. Possible reasons for an increase in the RT frequency at low dose rates are considered. A study of the frequency of occurrence of abnormal sperm heads (ASH) has shown that a dose rate of 9.4 X 10(-5) Gy/min, this frequency is independent of an accumulated dose and is the same as that at an acute dose of 3.0 Gy. At dose rates of 2.7 X 10(-6) and 5.8 X 10(-6) Gy/min, ASH frequencies were only slightly increased at all doses compared to the control level.

Genetic effects of 131I in reproductive cells of male mice.

A study was made of the frequencies of dominant lethal mutations (DLM) in pre- and post-meiotic germ cells, reciprocal translocations (RT) in spermatogonia and abnormal sperm heads (ASH) induced by a single intraperitoneal administration of Na131I with an activity of 1.48-740 kBq/g to male mice. The frequency of DLM was shown to increase only when postmeiotic cells were exposed to the radionuclide. The RT frequency increased insignificantly with increases in the dose of 131I. The ASH frequency increased only when maximal doses of 131I were administered. The relative biological efficiency (RBE) of 131I with reference to the indices under study is less than 1.

Evaluation of the genetic effects of 238Pu incorporated into mice.

The genetic effects of 238Pu incorporated into male mice were estimated by several tests. The activity of the administered 238Pu nitrate varied from 7 to 1850 Bq/g of body weight. The average alpha-radiation dose absorbed in the testes ranged from 2 to 96 cGy, with a dose rate of 0.004-1 cGy/day. alpha-Radiation from 238Pu was shown to induce dominant lethal mutations (DLM) and reciprocal translocation (RT), chromosomal fragmentation and formation of abnormal sperm heads (ASH). The effect does not depend on the average alpha-radiation dose absorbed in the testis. The relative genetic efficiency of alpha-radiation, as compared with that of chronic alpha-radiation for the indices under study, was about 10-20.

Genetic effects of testicular incorporation of 137Cs in mice.

A comparative estimation of the frequencies of genetic disorders induced in germ cells of male mice by a single or long-term exposure to incorporated 137Cs or to external gamma-radiation has been carried out. The frequencies of dominant lethal mutations induced by a single exposure were similar with both types of radiation. In stem cell spermatogonia the frequency of reciprocal translocations was significantly lower in the case of single 137Cs administration than upon external gamma-radiation. Upon long-term administration the genetic efficiencies of both types of radiation were similar.

Genetic effects of radiocarbon in reproductive cells of male mice.

The genetic effect of incorporated radiocarbon was studied after single, long-term (33 days) and chronic (6 and 12 months) treatment of male mice (CBA X C57B1) F1 with [14C]glucose. The genetic effect in male germ cells was estimated by 3 tests: DLM frequency in post- and pre-meiotic cells, RT frequency in stem spermatogonia and frequency of abnormal sperm heads. Absorbed doses in the gonads were: 0.22, 0.50 and 1.01 Gy, after a single exposure; 0.74 and 1.47 Gy, after long-term exposures; and 0.006 and 0.031 Gy, after chronic exposure for 6 months; and 0.013 and 0.066 Gy, for 12 months. The results suggest that DLM frequency in post-meiotic cells increased linearly with increasing the dose of 14C single and long-term exposures at a dose of 1.47 Gy only. A chronic treatment with [14C]glucose induced no increase in DLM frequency. RT frequency in stem spermatogonia was statistically significantly higher than the control level after the single and long-term exposure to 14C. A comparison of the results with the results of external single and chronic gamma-irradiation allows the conclusion that the relative genetic efficiency of radiocarbon as compared with that of gamma-rays is about 1.

Genetic disorders in mice exposed to radiation in the vicinity of the Chernobyl nuclear power station.

Induced reciprocal translocations in spermatocytes of mice, either caught or exposed at the site, were observed at all levels of radioactive contamination around the Chernobyl nuclear power station. The frequency of reciprocal translocations was relatively low and increased linearly with increasing dose rate. Among 74 male mice exposed as early embryos, four reciprocal translocation heterozygotes were found. Furthermore, an increase in embryonic mortality and frequency of abnormal sperm heads was observed after termination of exposure, but these decreased rapidly with post-exposure time.

[Genetic disorders in house mice after the accident at Chernobyl power plant]. / Geneticheskie narusheniia u domovykh myshei posle avarii na Chernobyl'skoi AES.

Genetic effects were studied in house mice caught from 1986 to 1994 in regions polluted by radionuclides as a result of the Chernobyl disaster. The dose rates of gamma-radiation on the soil surface ranged from 0.02 to 200 mR/h. The frequency of reciprocal translocations in mouse spermatocytes was relatively low, but increased with the dose rate. Embryo mortality was increased only in the progeny of male mice caught in 1987 in the area with maximum contamination. The frequency of mice heterozygous for recessive lethal mutations decreased with the time after the accident.

[Effects of para-aminobenzoic acid on radiosensitivity of mice of different strains]. / Vliianie paraaminobenzoinoi kisloty na radiochuvstvitel'nost' myshei raznykh linii.

The aim of the work was to study the possible protective effect of para-aminobenzoic acid (PABA) on the radiation lethality in mice of three inbred lines (BALB/cLacY, C3H/HeY, 101/Hy), stock YT1 and hybrids (C3H/He x 101/H)F1. The PABA solution was given to the mice intraperitoneally in single doses of 10, 50 and 100 mg/kg 40-50 min prior to irradiation with doses of 6 to 8 Gy depending on the line and sex of mice. The used doses of gamma-radiation were roughly LD75/30. The radioprotective effect of PABA was observed in all variants of the experiment but it was relatively low. The protection coefficient varied from 0 to 0.45. The protective effect depended on the line and sex of mice and on the dose of the injected substance.

[Mutagenesis in Muridae from regions with increased radiation level]. / Mutatsionnyi protsess u myshevidnykh gryzunov, obitaiushchikh v raionakh s povyshennym fonom radiatsii.

Genetic monitoring of wild populations of mouse-like rodents has been carried out since 1992 in areas with the increased radioactivity in the south of the Bryansk region. The radioactive background ranged from 0.20 to 2.20 mkGy/h. Over 400 rodents of different species have been examined. Bank vole constituted more than a half of the examined animals. The genetic effect of radiation was estimated by the frequency of micronuclei in normochromatic erythrocytes of peripheral blood and by the frequency of abnormal sperm heads. In house mice the frequency of reciprocal translocations and the level of embryo mortality were studied in the progeny of the caught male mice mated with intact laboratory females. The data obtained demonstrate that the yield of induced genetic disorders by all tests was relatively low and only in a few cases the frequency of disturbances tended to increase with an increase in the level of radionuclide contamination in the examined areas.

[Modification of the genetic effect of radiation in mice exposed in the region of the Chernobyl Atomic Electric Power Station]. / Modifikatsiia geneticheskogo éffekta radiatsii u myshei, éksponirovannykh v raione Chernobyl'skoi AES.

A study was made of the protective effect of beta-carotine and ephasol against genetic damages in germ cells of male mice, exposed within the zone of Chernobyl NPP or ingested by 137Cs. The analysis of reproductive function, frequencies of dominant lethal mutations, abnormal sperm heads, reciprocal translocations and testis mass decrease show that both agents are more effective in protection against reproductive function damages than against genetic effects.

[The radioprotective action of efazol under different conditions of irradiation of the germ cells of male mice]. / Radiozashchitnoe deistvie éfazola pri raznykh usloviiakh oblucheniia polovykh samtsov myshei.

A study was made of the protective effect of ephasol against genetic damages induced in mice germ cells by single, fractionated and chronic gamma radiation. Study of male reproductive ability, frequency of induced dominant lethal mutations, abnormal sperm heads and reciprocal translocation show that the efficacy of ephasol was higher in condition of chronic exposure.

[The micronucleus frequency in the somatic cells of murine rodents residing in a 30-kilometer area of the Chernobyl Atomic Electric Power Station]. / Chastota mikroiader v somaticheskikh kletkakh myshevidnykh gryzunov, prebyvavshikh v 30-kilometrovoi zone Chernobyl'skoi AES.

The chromosome aberration frequency in murine somatic cells was studied. Animals from natural populations as well as laboratory mice exposed within the ten-kilometers zone of the Chernobyl accident were examined. Increase in micronuclei rate in bone marrow cells, erythrocytes of peripheral blood and hepatocytes was found in animals exposed to more high background radiation. Under chronic exposure the pattern of effect dependence on dose rate was similar both in somatic and sex cells.

[The effect of chronic exposure to cadmium and gamma radiation at low doses on the genetic structures in mice]. / Vliianie khronicheskogo vozdeistviia kadmiia i gamma-izlucheniia v malykh dozakh na geneticheskie struktury myshei.

The DNA-protein cross-links (DPC) in mouse thymocytes and spleen lymphocytes, the number of abnormal sperm heads (ASH) and the number of micronuclei (MN) in normochromatic erythrocytes (NCE) of peripheral blood were studied in mice exposed to long-term low-intensity gamma radiation (0.072 cGy/days) and/or cadmium with drinking water (0.01 mg Cd2+/l) for 20, 40 and 80 days. The dependence of DPC level on the total dose (exposure time) of gamma radiation and/or cadmium is nonlinear. The maximal level of DPC in cells of lymphoid organs upon exposure to gamma radiation or cadmium was recorded on the 40-th day, and under combined exposure on the 20-th day of the experiment. The long-term exposure to cadmium or gamma radiation causes an increase in the ASH frequency. The increase in frequencies of MN in NCE and reciprocal translocations in spermatocytes was not found.

[Genetic effect of incorporated 137 Cs in male mice after single injection of the isotope]. / Geneticheskii éffect inkorporirovannogo 137 Cs u samtsov myshei pri odnokratnom vvedenii izotopa.

A comparative study of the incidence of genetic damages induced in mouse male germ cells by a single injection of 137Cs and external gamma-irradiation shows that the incidence of dominant lethal mutations in the postmeiotic cells is similar with both radiation types. The frequency of reciprocal translocations in stem cell spermatogonia was considerably lower with 137Cs than with external gamma-irradiation which might be attributed to the prolonged effect of the radionuclide.

[Genetic effect of incorporated 137 Cs on male mice after long-term administration of the isotope]. / Geneticheskii éffect inkorporirovannogo 137 Cs u samtsov myshei pri dlitelnom vvedenii izotopa.

A comparative study has been made of the incidence of genetic damages to male mouse germ cells induced by chronic action of incorporated 137Cs and external gamma-radiation. It has been shown that the genetic efficiency was nearly the same with both radiation types under conditions of equal, with respect to time and value, absorbed dose formation in gonads.