Sister-chromatid exchanges induced by mitomycin C after acute or chronic exposure of human lymphocytes to a low dose of X-rays.

Human peripheral blood lymphocytes from 10 male donors were exposed to mitomycin C with and without prior irradiation with 0.01 Gy X-rays. Acute or chronic irradiation of lymphocytes in G1 resulted in a decrease in the subsequent level of mitomycin C-induced sister-chromatid exchange aberrations. The effect was small (approximately 10%) with evidence of some variability between donors. By contrast no adaptive response was observed if the cells were treated in G0.