[Revision of th distribution of chromosome aberrations induced by chemical mutagens using the BUDR label]. / Peresmotr zakonomernostei raspredeleniia indutsirovannykh khimicheskimi mutagenami khromosomnykh aberratsii po kletkam s pomoshch'iu primeneniia BDU-metki.

Cell distribution was analysed with the help of the BrDU label for the number of chromosome aberrations and breaks induced by one-center (thiophosphamide and phosphamide) and two-center (dipine and fotrine) mutagens at the stage G0 in the Ist mitosis of human lymphocytes harvested at different times of culturing (from 56 to 96 h). The comparison was made between the type of aberration distribution in cells and the dependence of their frequency on the harvesting point for various mutagens. Poisson aberration distribution in cells for two-center mutagens was found to correspond to their constant frequency observed at different times of harvesting. On the other hand, for one-center mutagens, a geometrical distribution of chromosome breaks corresponded to an exponential decrease in their frequency in time. It is suggested that two-center chemical mutagens and ionizing radiation cause largely short-live damages which are realized into chromosome aberrations rather quickly (during one cell cycle). One-center mutagens, however, cause such damages that the probability of their transformation into chromosome aberrations is decreasing rather slowly in time, under the exponential law, and their realization into chromosome aberrations can occur in subsequent cell cycle.

[A quantitative evaluation of the changes in the proliferation of a human lymphocyte culture after mutagen exposure at the G0 stage]. / Kolichestvennaia otsenka izmeneniia proliferatsii kul'tury limfotsitov cheloveka posle vozdeistviia mutagenami na stadii G0.

Cell cycle delay of human lymphocytes treated with mutagens at G0 stage has been studied using a mathematical model. Cell cycle delay depends on entry cells into the first S phase and is independent on the cell cycle duration.

[Frequency of chromosome aberrations induced by mutagens of various functions in cells of the first division at various times of fixation]. / Chastota khromosomnykh aberratsii, indutsirovannykh mutagenami raznoi funktsional'nosti, v kletkakh pervogo deleniia na raznykh srokakh fiksatsii.

The dynamics of chromosome aberrations in human lymphocyte culture cells of the 1-st division after exposure in the G0 phase for 1h to functionally different alkylating mutagens - ethyleneimine derivatives (bifunctional phosphamide, threefunctional thiophosphamide, tetrafunctional dipine and pentafunctional photrin) was analysed. The frequency of chromosome aberrations was constant after exposure to "dicentric" mutagens (dipine, photrin) at all times of fixation, while under the action of "monocentric" mutagens (phosphamide, thiophosphamide) this declined significantly with increasing the duration of cultivation. The portion of aberrations of the chromatid remains unaltered in time, in case of both "dicentric" and "monocentric" mutagens, reaching 75% for "monocentric" and 50% for "dicentric" of the total number of chromosome aberrations.