@misc{oai:repo.qst.go.jp:00059901,
 author = {Aizawa, Shirou and Tanaka, Kaoru and Mori, Masahiko and Yoshida, Kazuko and 相澤 志郎 and 田中 薫 and 森 雅彦 and 吉田 和子},
 month = {Aug},
 note = {Radiation exposure is know to be highly leukemmogenic, but the mechanism action is not yet understood. Studies with the p53 heterozygous mouse have shown that a single dose of radiation can induce a high incidence of thymic lymphomas, most of which manifest the loss of wild-type p53 allele.  The loss of heterozygosity (LOH) in the p53 gene is thus thought to be an early event in radiation-induced thymic lymphomagenesis.   Thus, the p53 heterozygous mice might be a useful model for the study of consequences of radiation-exposure.  However, sensitive detection of p53-/- thymocytes appeared in p53+/- thymocyte population was needed to examine appearance of p53-/- thymocyte in p53 heterozygous (+/-) B10 mice in the early stage of radiation-induced thymic lymphomagenesis.  In this study, we characterized highly radioresistant thymocytes as a candidate of p53-/- thymocytes, because the enrichment of p53-/- thymocyte by a high dose of irradiation could be expected from the facts that p53+/- thymocytes are sensitive to radiation-induced apoptosis but p53-/- thymocytes highly resistant.   At various times post irradiation (6Gy) as lymphoma-inducing treatment,  p53 heterozygous B10 mice were treated with a high dose (30Gy)of whole-body irradiation to enrich p53-/- thymocytes and, 24 hours later, the remaining thymocytes were assayed for surface marker and p53 genotype.  In a significant fraction of the mice 7wks after 6Gy-irradiation, we observe an abnormal increase of relative cell number of CD4+CD8+ thymocytes remaining in the thymus of highly irradiated mice and such abnormal thymocytes could be detected even 5 weeks after  the irradiation.   The abnormal CD4+CD8+ thymocytes werer shown by PCR analysis of sorted cells to contain cells ith p53-/- genotype.  The data obtained so far suggest that p53-/- thymocytes may appear as prelymphoma cells within several weeks post irradiation in CD4+CD8+ thymocyte population of irradiated p53 heterozygous mice., 第１２回国際放射線研究会議},
 title = {Early detection of p53-/- thymocytes appeared during radiation-induced thymic lymphomagenesis in p53 heterozygous (+/-) B10 mice},
 year = {2003}
}