Radiatsionnaia biologiia, radioecologiia最新文献

The aim of the paper is to study modern tritium levels in various sources of the drinking water supply in the settlements situated in the riverside zone of the Techa. Almost everywhere the water entering water-conduit wells from deep slits (100-180 m) contains averagely 2-3 times higher tritium concentrations than the water from less deep personal wells, slits and springs. Tritium levels in the drinking water supply decrease with the distance from the dam; while in wells, springs and personal wells they are constant all along the river. The observed phenomenon can be explained by the fact that the river bed of the Techa is situated at a break zone of the earth crust, where the contaminated deep water penetrates from the reservoirs of the "Mayak" enterprise situated in the upper part of the regulated river bed. Less deep water sources (personal wells, slits and springs) receive predominantly flood, atmospheric and subsoil waters and are not connected with the reservoirs.

The influence of UV-light (240-390 nm) at dozes of 151 and 755 J/m2 on the content of membrane markers of lymphocytes using the method of flow cytometry was investigated. It was demonstrated that during incubation of UV-irradiated lymphocytes the change of their populational and sub-populational composition occurs. Expression of complexes of CD3, CD 19,.CD8, CD 16, CD25 and CD95 increased. This increase was caused mainly by de novo synthesis. UV-light had immunostimulating effect on CD8+ T-lymphocyte population. Together with the increase of cytotoxic cells and NK-cells, activation of lymphocytes (increased amount of CD25+ and CD95+ cells) took place. Amount of cells undergone apoptosis or necrosis increased proportionally to the dosage. These changes were more expressed during incubation of lymphocytes in nutrition medium without autological blood serum, e.g. under deficiency of growth factors and antioxidants.

We studied the state of the reproductive system of male rats after irradiation at a dose of 2.0 Gy, immobilization stress (6 hours/day for 7 days) and their combined effects. On the 30th day after the combined treatment (37 days after irradiation) a decrease in the testicular weight by almost 50% compared with the control and lesions connected with the process of spermatogenesis are observed. In the remote period--on the 60th day (67th after irradiation) the effect of irradiation and irradiation in combination with immobilization stress leads to a sharp drop in the number of epididymal sperm (up to 18% of the control), and a reduction of their viability. The reaction ofthe reproductive system to the immobilization stress is expressed in a certain increase in the mass of the testes and epididymis, moderate imbalances in the composition of spermatogenic cells in the testis tissue, and in the long term--in the increased number of epididymal sperm and the decrease in their viability. Changes of testosterone in the blood serum, especially significant for the combined effect, reflect impairments of the regulation of the reproductive system of males under these conditions. With regard to individual indicators of the reproductive system of male rats in some cases, the- combined effects of radiation and stress had a synergistic, or, on the contrary, antagonistic character.

The purpose of the present research was to estimate the intensity of the apoptotic death of lymphocytes during the period of carcinogenic effect realization in the residents of the Techa riverside villages. The investigation included analyses of the frequency of lymphocytes at the early and late stages of apoptosis and necrosis of peripheral blood lymphocytes using the method of FITC Annexin V, lymphocyte counts at the stage of DNA fragmentation using the TUNEL method, and the number of CD95(+)-lymphocytes. In the capacity of additional tests, loading tests involving in vitro irradiation at the dose of 1 Gy of a suspension of lymphocytes and incubations for 5 and 24 hours were used. Activation of the initial apoptotic and necrotic death of peripheral blood lymphocytes was revealed in the persons chronically exposed to low-intensity radiation within the range from 0.01 to 4.23 Gy. Exposed patients demonstrated a decrease in the number of CD95(+)-cells as compared to unexposed patients. The results of the cell death studies in the persons residing in the Techa riverside villages testify indirectly to the genomic instability of the peripheral blood lymphocytes.

Mesenchymal stem cells (MSC) exist in the brain in addition to the neural stem cells (NSC). The aim of this work was to investigate the sensitivity of mouse brain MSC (MSC(BR)) to sublethal doses of γ-radiation in comparison with the sensitivity of bone marrow MSC (MSC(BM)) and NSC and to study the effects of γ-irradiation at low doses on these cells. Cells were exposed to γ-radiation (137Cs) at the doses of 10 to 200 mGy at a dose rate of 10 mGy/min; higher doses were achieved at the dose rates of 200 and 500 mGy/min (60Co). The survival of cells was assessed by counting living cells after staining with trypan blue in the Goryaev's chamber or using the MTT test for NSC growing as neurospheres. SP fraction was measured using flow cytometry after incubation with rhodamine-123. Exposure to the doses in the range of 10 to 500 mGy stimulated cell proliferation. The maximum decrease in the cells number was seen on the seventh day after irradiation and it was practically the same for the MSC(BR) and MSC(BM). NCS were more radiosensitive than MSC. Exposure to the doses of 100 to 500 mGy stimulated cells proliferation of all SCs except of MSC(BM). It was shown that the size of SP fraction of MSC(BR) was diminished after γ-irradiation at low doses. Thus, the stimulation of cell proliferation after γ-irradiation at low doses is accompanied by the redistribution of distinct cell subpopulations: the decrease in the SP fraction and the increase in the general population of cells were observed.

Methodological approaches to the organization of counter measures are considered taking into account the landscape features of the radioactively contaminated territories. The current status and new requirements to the organization of counter measures in the contaminated agricultural areas are analyzed. The basic principles, objectives and problems of the formation of counter measures with regard to the landscape characteristics of the territory are presented; also substantiated are the organization and optimization of the counter measures in radioactively contaminated agricultural landscapes.

The database of publications on molecular epidemiology of RET/PTC rearrangements in sporadic and radiogenic thyroid papillary carcinoma has been formed (197 sources at the end of 2014; coverage of 100%). Based on this database a pooled analysis of data on the rates of RET/PTC1, RET/PTC3 and RET/PTC in total was conducted. Statistical approach involves a simple pooling, as well as calculations on the models of random and fixed effects. Since almost all the strata were characterized by heterogeneity, simple pooling and random effect models were adequate. Calculations using both models led to almost identical results. For rates of RET/PTC1, RET/PTC3 and RET/PTC in total with respect to formed carcinoma striations the following values (pooling, in %) were obtained: sporadic, total--13.2; 8.9; 21.2; sporadic, adults--13.3; 9.9; 21.1; sporadic, children--22.4; 17.5; 44.5; radiogenic, total--20.9; 20.3; 40.4; radiotherapy (exposure in childhood)--31.1; 11.8; 42.5; children affected after the Chernobyl accident--19.9; 23.6; 46.1; radiological incidents (exposure in adulthood)--19.9; 7.7; 18.4. Statistically proven is the reliability of differences of carcinoma indicators for children compared with adults (both sporadic and radiogenic tumors) and for radiogenic cancer compared with sporadic. The greatest increase in rate after irradiation was found for RET/PTC1, previously characterized in vitro as one of radiogenic types of RET/PTC.

The article gives information about the microorganisms inhabiting in surface storages of solid radioactive waste and deep disposal sites of liquid radioactive waste. It was shown that intensification of microbial processes can lead to significant changes in the chemical composition and physical state of the radioactive waste. It was concluded that the biogeochemical processes can have both a positive effect on the safety of radioactive waste storages (immobilization of RW macrocomponents, a decreased migration ability of radionuclides) and a negative one (biogenic gas production in subterranean formations and destruction of cement matrix).

A review of molecular genetic, radiobiological and molecular epidemiological studies of gene (chromosome) rearrangements RET/PTC in the cells of the thyroid gland as well as the laws in relation to radiation exposure in vitro, in vivo and human populations identified with them are submitted. The data on the c-RET gene and its chimeric constructs with the gene-donors (RET/PTC rearrangements) are considered. The information about the history of the RET/PTC discovery, their types, carcinogenic potential and specificity both to tumor and non-tumor thyroid disease especially for papillary thyroid carcinoma are provided. The data (seven studies) on the induction of RET/PTC after irradiation of tumor and normal thyroid cells in vitro and mice are reviewed. The mechanisms of RET/PTC induction may be associated with DNA double strand breaks and oxidative stress. Some information (three publications) about the possibility of RET/PTC induction by low doses of radiation with low LET (to 0.1 Gy) is given and it is concluded that their potential evidentiary is generally weak. The achievements in the molecular epidemiology of RET/PTC frequency for exposed and unexposed cohorts are stated. At the same time it is noted that, despite the vast array. of data accumulated from 30 countries of the world and more than 20 years of research, the formed provisions are weakly confirmed statistically and have no base corresponding to the canons of evidence-based medicine. The possibility of use of the RET/PTC presence or their frequencies as markers of the papillary thyroid carcinomas and, specifically, their radiogenic forms, is considered. In the first case the answer may be positive, while in the second, the situation is characterized by uncertainty. Based to the above mentioned we came to a conclusion about the need of a pooled or meta-analysis of the totality of the published data.