[The results of 25 year-cytogenetic investigation of survivors exposed to different doses of irradiation in the Chernobyl accident].

Changes of registered levels of chromosome aberrations were studied in the peripheral blood lymphocyte cultures of 74 patients irradiated as a result of the Chernobyl accident by the instrumentality of the routine method during 25 year. The initial dose estimations by average dicentrics frequency varied from 0.2 to 9.8 Gy On the whole, the model of a double exponential type was the most adequate for the quantitative description of elimination of cytogenetical indices associated with different types of unstable chromosome aberrations. High individual variability of the elimination rate of chromosome aberrations and its dependency from the value of originally evaluated dose were discovered in the first period. The computer method of retrospective dose estimation was developed on the basis of this material. The method is based on the analysis of cell distributions in accordance with the number of dicentrics and as a whole, unstable chromosome aberrations, contained in them. In addition the dynamics of translocation frequencies in the peripheral blood lymphocyte cultures of a number of patients from this contingent was investigated starting from 10 years after irradiation by the instrumentality of FISH-method of chromosome staining.

[Cytogenetical indices in remote times after acute irradiation of people. The computer method of retrospective dose estimation].

The computer method of retrospective dose estimation is used for the reconstruction of dose irradiation of victims in the result of Chernobyl accident by the results of repeated cytogenetical investigations in remote time after exposure. This method is based on the analysis of cell distributions in accordance with the number dicentrics and with unstable chromosome aberrations contained in them by special computer program. Received data demonstrate that for more exact reconstruction of original absorbed doses the need additional correction taking into account time after irradiation or frequencies of atypical chromosomes ensued from account of chromosome aberrations in remote time after exposure is needed.

[Elimination of chromosome aberrations in lymphocyte cultures of the peripheral blood in people at remote time after acute irradiation].

The changes in registered levels of chromosome aberrations are studied in the peripheral blood lymphocyte cultures of patients irradiated in result of Chernobyl accident. All 71 patients were examined with a different frequency for different survival patients. The initial evaluations of the doses for them by the average frequency of dicentrics were realized at the nearest terms after the irradiation (from 0.2 before 9.8 Gy for different patients). Repeated blood samples were collected during 6 years after the accident. On the whole the model of exponential type Y(T)/Y(0) = c + exp(b(0) + b(1)T), where Y(T)--the frequency dicentrics at the time of examinations; Y(0)--the originally discovered dicentric frequencies; T--the time past after irradiation (days) was the most adequate for the quantitative description of the elimination of cytogenetical indices associated with different types of unstable chromosome aberrations. Also as a result of this study high individual variability of the elimination rate of the chromosome aberrations and its dependence from the value of the originally evaluated dose were discovered.