title: Chromosome pulverization in micronuclei induced by tritiated thymidine.
abstract: Cultures of a pseudodiploid cell line (Don) of Chinese hamster origin were exposed to varying doses of tritiated thymidine (TdR-(3)H) for relatively long periods of time. In addition to previously observed chromosomal aberrations) such as breaks and reunions, a substantial number of interphasic cells with micronuclei and of metaphases associated with pulverized chromosomes was found; both phenomena were dependent on exposure time to and concentration of TdR-(3)H. The former phenomenon appeared to result from the effects of the beta-emissions originating in the TdR-(3)H. A possible interpretation for chromosome pulverization induction is presented, emphasizing the derivation of the pulverized material from micronuclei in a common cytoplasm with a metaphase nucleus. These observations further substantiate our previously advanced hypothesis regarding the essential role played by substances present in a mitotic cell in the induction of chromosome pulverization and nuclear membrane dissolution.
mesh_terms: D000818:Animals; D001345:Autoradiography; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects*; D002478:Cells, Cultured / Q000187:drug effects*; D002843:Chromatin; D002869:Chromosome Aberrations / Q000187:drug effects*; D006224:Cricetinae; D005856:Germ-Free Life; D008168:Lung; D008722:Methods; D008938:Mitosis / Q000187:drug effects; D013936:Thymidine / Q000494:pharmacology*; D013997:Time Factors; D014316:Tritium
chemical_list: D002843:Chromatin; D014316:Tritium; D013936:Thymidine