EFFECTS OF BETA-RADIATION ON SISTER-CHROMATID EXCHANGES IN CULTURED HUMAN-LYMPHOCYTES

The incidence of sister chromatid exchanges (SCE) due to .beta.-radiation was investigated in cultured human lymphocytes using the BrdU[bromodeoxyuridine]/Giemsa technique. Cultures treated continuously with 0.001 and 0.01 .mu.Ci of [3H]uridine showed no increase in either chromosome abnormalities or SCE. Continuous treatment with 0.1 .mu.Ci resulted in a significant increase in chromosome aberrations but no increase in SCE, while treatment with 0.2 .mu.Ci gave both an increase in chromosome aberrations and SCE. Cultures given a 4 h pulse with 1.0 .mu.Ci showed a significant increase in both SCE and chromosome aberrations. Low levels of .beta.-radiation apparently do not cause an increase in SCE in human lymphocytes. Some, if not all, of the exchanges observed at low levels of .beta.-radiation with autoradiography may be spontaneous events.