Radiosensitivity of swine lymphocytes: in vitro modifications of the cell cycle and kinetics of the appearance of chromosomal aberrations.

gamma-Radiation-induced modifications of the cell cycle of swine lymphocytes have been studied by the harlequin chromosome technique and by the uptake of tritiated thymidine. The radio-induced mitotic delay is 1 h per Gy. This delay occurs mainly in the lengthening of the initial phase prior to the first mitosis. The gamma-ray dose-response curve for dicentrics in first-division cells has been studied after different durations of culture. The radio-induced mitotic delay varied within the lymphocyte population: the mitosis commences much later as the cells exhibit a greater number of anomalies (dicentrics). The dose-effect relationships which can be established are thus closely conditioned by the duration of the culture. The mitotic delay observed in irradiated swine lymphocytes could amount to a restoration phase of duration varying with the importance of the induced damage.