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.
Odagiri
Y
Y
Department of Haematology, Flinders Medical Centre, Bedford Park, SA, Australia.
Dempsey
J L
JL
Morley
A A
AA
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