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Background.Cytogenetic damage (СD) in lymphocytes induced by low doses (up to 0.1 Sv) of ionizing radiation (IR) is the main cytogenetic sign of individual radiosensitivity of the human body. In addition to DNA repair and cell death, which affect the formation of СD and its elimination, IR effects on the cell can be manifested through changes in proliferation of cells with unrepaired DNA damage. The system of cyclins and cyclin-dependent kinases (CDK), which provide coordination of mitotic events during passage of a cell through the cell cycle, plays a crucial role in regulation of cell proliferation.Aim.To evaluate the relationship of single-nucleotide polymorphisms (SNPs) of cell cycle genes with an increased frequency of СD in workers of a nuclear power plant affected by chronic occupational radiation exposure in the dose range of 100–500 mSv.Materials and methods.The object of the study was blood of 55 conditionally healthy workers of Siberian Chemical Plant (SCP) who were affected by chronic occupational radiation exposure (gamma radiation) in the dose range of 100–500 mSv. A standard cytogenetic analysis of blood lymphocytes was performed for all examined individuals. Genomic DNA was isolated from the blood of the workers using the QIAamp DNA Blood Mini Kit (QIAGEN, Germany). DNA was genotyped using 257 SNPs of cyclin genes and neighboring intergenic regions using DNA microarrays from the high-density CytoScan HD Array (Affymetrix, USA).Results.Taking into account the Bonferroni correction, only statistically significant associations of SNPs with the frequency of dicentric chromosomes were found; all other types of chromosomal aberrations did not show statistical significance. The rs803054CCNI2was associated with an increased frequency of dicentric chromosomes arising under the influence of chronic occupational radiation exposure.Conclusion.The discovered SNP (rs803054), whose recessive genotype is associated with an increased frequency of dicentric chromosomes in workers of SCP exposed to radiation at doses of 100–500 mSv over a long time, can be considered as a potential marker of individual radiosensitivity. To confirm the identified associations, further validation studies are needed on an expanded sample of people affected by chronic occupational radiation exposure.

Mid-annual indicators of the general death rate during the period with 1996 on 2000 of on Tomsk Region, as well as on to the Siberian Federal district, and as a whole across the Russian Federation practically did not differ from similar indicators during the period with 1992 on 1996 of (their distinctions are doubtful — p > 0,05). Despite some decrease in rates of growth of death rate in 2001—2005 of, its level remains high — in 2001 it was 13,3, and in 2005 — 14,5 on 1000 population. The greatest number of people dies of illnesses of system of blood circulation, accidents, poisonings and traumas, new growths. Relative density died of the specified reasons from number of all died made in 2005 according to — 46,3%, 15,7% and 14,0%. Especially attracts attention growth of death rate of the population of area in 2,6 times in 2005 in comparison with 2001 from the reasons connected with the use of alcohol growth of death rate from the given reasons at persons of able-bodied age is More expressed. Mid-annual level of parent death rate in 2001—2005 of has decreased in comparison with 1996—2000 of on 29,2%. Strengthening of health is spent to areas not only women and children, but also all population the big complex of the actions directed on decrease of parent and infantile death rate, preventive maintenance of illnesses of system of blood circulation, etc.

Leukemia (71,2%) brings the basic contribution to the structure of hemoblastosis. The indices of leukemia disease both boys and girls of Seversk exceed the same ones in Tomsk in the age groups of 0-4 and 10-14; though according to the reliable information it is shown only at boys. It is established that the boys morbidity of hemoblastosis in Seversk exceeds the same one in Tomsk only in the age group of 0-4.