Some problems of spontaneous and induced mutagenesis in mammals and man.

The culture time of rabbit lymphocytes (41–42 h) that provides cells in their first post-stimulation mitosis, was estimated on the basis of the mitotic index, dicentric yield and presence of the cells with these aberrations unaccompanied by acentric fragments, studied as a function of culture duration. The cells obtained in metaphase from cultures terminated at this time displayed no donor-to-donor variation where induction of dicentrics by X-rays was concerned.Rabbit venous blood was irradiated in vitro with a range of X- and gamma-ray doses, and dose-effect curves were obtained by regression analysis. Sixteen rabbits were irradiated in vivo (uniform whole-body irradiation), and blood was sampled 10 min, 6, 24, and 48 h after exposure. The frequency of dicentrics in the lymphocytes cultured did not change significantly over the first 24 h after irradiation. Dose-effect relationships in vivo fell within one standard error confidence limits of the respective curves in vitro. The authors conclude that the latter may be used for estimation of dose in vivo under conditions of homogeneous whole-body irradiation.