title: Cytosine arabinoside is a potent clastogen and does not affect the repair of X-ray-induced chromosome fragments in unstimulated human lymphocytes.
abstract: The metabolic inhibitor of DNA synthesis cytosine arabinoside (ara-C) is known to induce chromosome aberrations in human lymphocytes. It has been recently argued, however, that there is no unequivocal evidence that ara-C can damage chromosomes directly. Therefore, the effect of ara-C on unstimulated human lymphocytes was examined directly by means of the premature chromosome condensation technique. In about 50% of the cells, ara-C effectively induced chromosome fragments, which did not show rejoining even after the chemical was washed out. These results suggest that a possible selection against damaged cells in their progress to mitosis could result in the low yields of ara-C-induced chromosome aberrations reported in the literature. The effect of ara-C on the repair of radiation-induced chromosome aberrations was also examined. Ara-C did not affect the rejoining of the chromosome fragments induced in unstimulated human lymphocytes by 6 Gy of X-rays.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D002875:Chromosomes / Q000528:radiation effects; D006224:Cricetinae; D003412:Cricetulus; D003561:Cytarabine / Q000633:toxicity*; D004260:DNA Repair / Q000187:drug effects*; D005260:Female; D006801:Humans; D007399:Interphase / Q000528:radiation effects; D008214:Lymphocytes / Q000528:radiation effects; D009154:Mutation / Q000187:drug effects*; D010053:Ovary; D014965:X-Rays
chemical_list: D003561:Cytarabine