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Studies on energy dependency of biological effects of neutrons and risk estimation

中子生物效应能量依赖性研究及风险评估

基本信息

批准号：
09680530
负责人：
KUBOTA Nobuo
金额：
$ 1.86万
依托单位：
Ibaraki Prefectural University of Health Sciences
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09680530/
关键词：
Neutron Mutation HPRT Neutron energy V79 中性子線クロマチン損傷

项目摘要

We have examined the neutron energy dependency of cell killing and mutation induction at hprt locus in Chinese hamster V79 cells. Monoenergetic neutrons at 0.32, 0.57, and 1.2 MeV were generated at the Hiroshima University Radiobiological Research Accelerator (HIRRAC) Facility, and were used to irradiate cells. The variation in RBE with neutron energy for the end points of cell survival and hprt mutation induction was observed. When compared to 137Cs gamma-rays, all neutron energies were more effective at both cell killing and induction of mutation. Over the range of the neutron energies examined, we found that cytotoxicity increased as the energy decreased from 1.2 to 0.32 MeV.In comparison to gamma-rays, RBEs for cell lethality at 10% survival were 5.7, 6.7, and 7.6 for 1.2, 0.57, and 0.32 MeV, respectively. Mutation induction, on the other hand, was highest at 0.57 MeV with a gradual decrease at 1.2 and 0.32 MeV.RBEs for mutation induction were 9.7, 19.4, and 13.9 for 1.2, 0.57, and 0.32 MeVneutrons.We isolated independent V79 cell mutants at the hprt locus from untreated and neutron-exposed cells and determined the genetic changes underlying the mutation by multiplex polymerase chain reaction (PCR)-based exon deletion analysis. Preliminary results are suggestive of a specific relationship between deletion patern and neutron energy.

我们研究了中国仓鼠V79细胞中hprt位点的细胞杀伤和突变诱导的中子能量依赖性。广岛大学放射生物学研究加速器 (HIRRAC) 设施产生 0.32、0.57 和 1.2 MeV 的单能中子，并用于照射细胞。观察细胞存活和 hprt 突变诱导终点的 RBE 随中子能量的变化。与 137Cs 伽马射线相比，所有中子能量在细胞杀伤和诱导突变方面都更有效。在检查的中子能量范围内，我们发现随着能量从 1.2 MeV 降低到 0.32 MeV，细胞毒性增加。与伽马射线相比，10% 存活率时细胞致死率的 RBE 分别为 1.2、0.57 和 0.32 MeV 的 5.7、6.7 和 7.6。另一方面，突变诱导最高为 0.57 MeV，并在 1.2 和 0.32 MeV 时逐渐下降。对于 1.2、0.57 和 0.32 MeV 中子，突变诱导的 RBE 分别为 9.7、19.4 和 13.9。我们从未处理和中子暴露的细胞中分离出 hprt 基因座的独立 V79 细胞突变体，并确定了多重突变背后的遗传变化基于聚合酶链反应（PCR）的外显子缺失分析。初步结果表明缺失模式与中子能量之间存在特定关系。