The cytogenetic effects of aflatoxin and gamma-rays on human leukocytes in vitro

Chromosomes from human leukocyte cultures in vitro were treated with γ-rays (200 R), aflatoxin (50 μg/ml, dissolved in dimethyl sulfoxide (DMSO)) and with a combination of both. At the time of treatment (48 h) cells were in all stages of interphase but G₁ cells were evidently predominant. All types of chromosome aberration were observed. Frequencies of chromosome-type aberrations were much higher than those of chromatid type after γ-ray treatment, but these types of chromosome aberration did not differ greatly when the cultures were treated with aflatoxin. Apparently the cytogenetic effect of aflatoxin was delayed longer than was that of irradiation. The present data also suggest the additive effect of γ-rays and aflatoxin in the combined treatment.