[Radioecological biomonitoring of the radioactive waste long-term storage territories].

Radionuclide release to environment is possible during long-term storage of the low and middle activity radioactive waste on specially equipped territories, which leads to radioactive background increase and to permanent radiation influence to biocenosis. For an ecological situation control in such places it is need to provide a biomonitoring using the method of complex estimation of the morphological changes on whole organism and internal organs levels (presents of tumors, teratogenic effects), the hematological indexes reflected quantifies and qualifies changes in blood, cytogenetic distribution (bone marrow polychromatic erythrocytes with micronuclei) and distributions on molecular level (alterations of DNA structure lead to increase in the DPC level).

Radiobiological monitoring of striped field mouse populations in the Moscow recreation forest "Kuzminki".

The results of radiometric and haematological studies of striped field mice (Apodemus agrarius) sampled over the years 1995-2003 from the territory of the preserved radioactive waste burial (RWB), which is located in the Moscow recreation forest "Kuzminki", are presented and discussed in the paper. It was shown that the level of 90Sr-90Y content in mice sampled from the RWB area varies within the range of 0-1200 Bq/kg with an average of 98.7+/-21.5 Bq/kg. The content of 90Sr-90Y in the body of 80% of the mice sampled from the RWB area was below 100 Bq/kg. Only in 4% of the sampled mice, the 90Sr-90Y specific radioactivity was above 300 Bq/kg. Haematological indications of the animals sampled from the RWB area were within the range of normal physiological fluctuations. Nevertheless, a slight but statistically significant increase in the average amount of erythrocytes and the average percentage of banded neutrophils was registered in peripheral blood of the mice.

[Estimation of genetic effects of chronic exposure to low-dose rate gamma-radiation by cytogenetic methods and DNA-comet assay]. / Otsenka geneticheskikh éffektov khronicheskogo vozdeistviia nizkointensivnogo gamma-izlucheniia tsitogeneticheskimi metodami i metodom DNK-komet.

The study of genetic effects in CBA/lac mice exposed for 1 year to constant low dose-rate gamma-radiation at a dose-rate 63 cGy/year has been carried out. We have shown the significant increase in the DNA breaks' level in spleen lymphocytes by comet-assay beginning from the total absorbed dose of 20 cGy. It is possible that the DNA breaks' level increase resulted from the structural rearrangement of chromatin or induction of lymphocyte proliferation. The results obtained by micronucleus test have proved that the mutagenic effect of chronic low dose-rate gamma-radiation depends on cell type and respectively on cell proliferation rate, cell differentiation, etc. So, by the end of experiment the significant increase in the frequency of PCE with micronuclei (MN) was observed. However, in contrast, the frequency of NCE with MN was not increased. No significant increase in the percent of lung cells with MN was registered.

[The estimation of molecular and cytogenetic effects in mice exposed to chronic low dose gamma-radiation]. / Otsenka molekuliarnykh i tsitogeneticheskukh éffektov khronicheskogo vozdeistviia nizkointensivnogo gamma-izlucheniia u myshei.

Molecular and cytogenetic parameters were estimated in male CBA/lac mice exposed to chronic low dose-rate gamma-radiation (62 cGy/year) for 40, 80, 120, 210, and 365 days. After 40 days of exposure (6.7 cGy), spleen lymphocyte susceptibility to hydrogen peroxide was shown to increase. However, beginning from the day 120 of the treatment (20.4 cGy), the opposite effect was observed. An increase in number of the DNA-protein crosslinks was recorded in spleen lymphocytes only on day 40 of the experiment. The number of DNA breaks increased significantly beginning from day 120 of the experiment, as shown by the DNA-comet method. On the day 210 of irradiation, the frequency of abnormal sperm heads in the mice significantly increased. The number of normochromatic micronucleated erythrocytes of the peripheral blood remained unchanged.

[Assessment of single-stranded DNA breaks in spleen lymphocytes using the DNA comet assay in the long term after acute irradiation of mice at sublethal and moderately-lethal doses]. / Otsenka metodom DNK-komet odnonitevykh razryvov DNK limfotsitov selezenki v otdalennye sroki posle ostrogo oblucheniia myshei v subletal'nykh i sredneletal'nykh dozakh.

The single-strand DNA level in spleen lymphocytes of BALB/c male-mice after 11 month acute exposure to gamma-radiation at doses 1, 3 and 6 Gy has been investigated by comet assay. The results of our study showed that at 11 month after irradiation at different doses a significant increase in the level of DNA breaks in spleen lymphocytes and decrease in the total number of these cells in mice was registered. It is possible that the increase in the DNA breaks is due to the effort of the compensatory proliferation process in lymphoid system that can give the increase in the number of different genetic disturbances in lymphocytes.

[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.

[Changes in the number of DNA-protein cross links in spleen lymphocytes of mice exposed to low intensity low dose gamma irradiation]. / Izmeneniia kolichestva DNK-belkovykh sshivok v limfotsitakh selezenki myshei pri vozdeistvii nizkointensivnogo gamma-izlucheniia v malykh dozakh.

Levels of DNA-protein cross-links (DPC) and DNA single-strand breaks (SSB) in spleen lymphocytes were studied in mice exposed to low-intensity gamma-radiation (1.7 mGy/day) for 1, 4, 10, 20, and 30 days. The spleen mass and count of lymphocytes isolated from this organ also has been investigated. The significant increase in the DPC level as compared to the control occurred on the 10-th and 30-th days of irradiation at doses of 1.7 and 5.1 cGy, accordingly. The number of spleen lymphocytes normalized to organ mass significantly decreased on the 4-th and 30-th days of the experiment. No increase was found in levels of alkali-labile sites and SSB. In contrast, the increase in the amount of duplex form DNA was recorded on the 4-th and 30-th days of the experiment. Our indicate that DPC formation after irradiation at low doses represents some form of cellular response to the damaging agent.

[DNA-protein cross-links in leukocytes of the field mouse (Apodemus agrarius) and the bank vole (Clethrionomys glareolus) dwelling in the territory of a radioactive waste storage station]. / DNK-belkovye sshivki v leikotsitakh polevykh myshei (Apodemus agrarius) i ryzhikh polevok (Clethrionomys giareolus), obitaiushchikh na territorii punkta zakhoroneniia radioaktivnykh otkhodov.

DNA-protein cross-links in white blood cells of Apodemus agrarius and Clethrionomys glareolus dwelling in the territory of the guarded zone of the radioactive waste storage in Sergievo Posad (area with gamma-background 50-400 microR/h) have been determined. As a control the animals from sanitary protected area of Sergievo Posadsky department (gamma-background on the soil surface is 8-10 microR/h) was used. It was found that the doses received by Apodemus agrarius and Clethrionomys glareolus, resulted in increasing of the DNA-protein cross-link level in the Apodemus agrarius white blood cells by a factor of 1.8, and in Clethrionomys glareolus by a factor of 1.4, in comparison with control. The increase of DNA-protein cross-link number reliably correlates with the beta-emitting nuclide content in animal bodies. The changes in the number white of cells and in the white blood composition were not observed.

DNA-protein cross-links in different organs of mice induced by the combined action of zinc and gamma-irradiation.

Fractional whole-body gamma-irradiation of mice at total doses of 0. 5-1.5 Gy induces increased DNA-protein cross-links (DPCs) in thymus, spleen, and brain, whereas in liver no DPCs are detected. Chronic administration of zinc ions in drinking water at concentration 10 mg/liter for 20-30 days increased DPCs in thymus, spleen, brain, and liver of mice. The combined action of zinc ions and gamma-radiation produced a significantly lower amount of DPCs than was induced by the separate action of these agents.

DNA-protein cross-links in leukocytes of mice induced by Zn, Cd, and Pb.

A single subdermal injection of CdCl2 or Pb(CH3COO)2 results, together with remarkable changes in the blood cell pattern, in increased DNA-protein cross-links in mouse leukocytes in 24 h; after 15 days the DNA-protein cross-linking returned to the initial level. In contrast, after injection of ZnSO4 a high level of DNA-protein cross-links is retained during the whole observation period (15 days). In the studied range of doses the formation of DNA-protein cross-links is proportional to the logarithm of the dose.