[Chromosome aberrations induced by bleomycin in the lymphocytes of young and old persons].

Phytohemagglutinin-stimulated lymphocytes from 20 young (16-28 years) and 20 old (70-88 years) healthy subjects have been investigated for chromosome aberrations before and after exposure to bleomycin in G2 phase of the cell cycle. No differences were found in unexposed cultures between young and old donors. After treatment with bleomycin the frequency of chromosome aberrations was significantly higher in the old subjects than in the young ones (p less than 0.05). The results suggest that the different interaction between the mutagen and DNA may be caused by the decreased capacity of the excision repair system in the cells of the old individuals.