[Use of the method of differential staining of sister chromatids for the study of cytogenetic radiation effects in human lymphocytes].

Chromosome aberrations in human peripheral blood lymphocytes cultivated with and without 5-bromodeoxyuridine (BDU) were studied and compared. In BDU cultures, chromosome aberrations were counted in the cells of the first postradiation mitosis. The rate of acentric aberrations and that of dicentrics + rings in these cultures were respectively lower and higher than in cultures without BDU. In BDU cultures, almost all the dicentrics had concomitant paired fragments, whereas in cultures without BDU, the rate of the dicentrics without fragments amounted to 0.3-6,2%. The distribution of the dicentrics among the cells in both the cultures obeyed the Poisson law. It is suggested that the differences cited are determined by the presence in the cultures without BDU of the cells of the 2d or subsequent mitoses. To support this suggestion, the authors studied chromosome aberrations in the 1st-4th postradiation mitoses. The cells of the 2d and 3d mitoses showed a high rate of acentric fragments. The number of the dicentrics was about twice as decreased after the cells experienced the 1st and each subsequent mitosis. In the first mitosis, all the dicentrics had concomitant paired fragments, whereas in the 2d-4th mitoses, the share of the dicentrics without fragments ranged from 18.7 to 95.5%. The advisability has been shown of using the differential staining of sister chromatids for identification of the cells of different generations in the culture, for raising the accuracy of counting the radiation-induced chromosome aberrations in human lymphocytes, and for studying the mechanisms of their elimination in the process of experiencing by the cells of the first and subsequent mitoses.