The effect of X-irradiation on cell cycle progression and chromatid aberrations in stimulated human lymphocytes using cohort analysis studies.

Stage sensitivity for the production of chromatid-type aberrations and mitotic delay has been investigated in a stimulated human lymphocyte population, following an absorbed dose of 1.5 Gy 250 kVp X-rays. BrdU replication banding was used to obtain a fine analysis of the cell cycle and to permit cohort analysis. Fluctuations in yield with sample time were found for all aberration categories, but these could not be related simply to either the developmental stage of the cells at time of exposure, or to the time-to-run to metaphase. In general G2 and late S cells had higher aberration yields than early S and pre S cell populations. Mitotic delay and perturbation at this dose extends to all sub-phases of S and is as great, if not greater, in the earliest S cells as it is in G2.