Damage to lymphocytes by X-ray and bleomycin measured with the cytokinesis-block micronucleus technique.
Chromosome damage induced by X-irradiation or bleomycin was measured using the cytokinesis-block micronucleus assay in the peripheral blood lymphocytes of 6 newborn, 8 young and 10 elderly individuals. An increase in the frequency of spontaneous micronuclei with age was observed. There was no difference in the X-irradiation-induced micronucleus frequency between the 3 groups. There was a significant increase with age in the number of micronuclei induced by bleomycin. Kinetochore-labelling studies revealed that the percentage of kinetochore-positive induced micronuclei was higher for bleomycin (36.2-43.3%) than for X-irradiation (17.1-19.7%). The age-related increase in frequency of spontaneous or bleomycin-induced micronuclei was due to increases in both kinetochore-positive and kinetochore-negative micronuclei. The frequency of kinetochore-positive or -negative micronuclei induced by X-irradiation was not different between the 3 age groups. These results suggest that bleomycin is more potent in inducing whole-chromosome loss than X-rays, and that lymphocytes from aged individuals are more sensitive to bleomycin in terms of both chromosome breakage and whole chromosome loss.
Department of Haematology, Flinders Medical Centre, Bedford Park, SA, Australia.
Y
Y
Odagiri
J L
JL
Dempsey
A A
AA
Morley
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000235:genetics*; D001761:Bleomycin / Q000494:pharmacology*; D002455:Cell Division; D004249:DNA Damage; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D007231:Infant, Newborn; D008214:Lymphocytes / Q000187:drug effects / Q000528:radiation effects; D015162:Micronucleus Tests
D001761:Bleomycin