MUTATION-TRANSFORMATION: NEUTRON DAMAGE AND REPAIR

暴露在电离辐射下是诱变的，就像在植物中证明的那样， 微生物和哺乳动物细胞。然而，人们对此知之甚少 在哺乳动物细胞中辐射诱导突变的潜在过程，以及 辐射传递方式对诱变过程的影响 和/或修复过程。利用啮齿动物和人类细胞，主要目标是 建议研究的目的是确定：(1)剂量依赖关系 来自Janus反应堆的裂变能谱中子引起的突变， 与X射线或伽马射线进行比较，并估计相对生物学 此终点的有效性(RBE)；(2)对突变的影响 导致高剂量辐射剂量的分馏和延长 和低LET辐射(分别是Janus中子和X或伽马射线)， 交付方式是否表明修复机制的作用；(3) 裂变中子不同输运方式对核反应的影响 肿瘤转化的发生率，与突变进行比较 归纳以了解这两个终点是否在机械上相关； (4)高、低LET辐射在诱导过程中的相互作用 突变和肿瘤转化，以获得进一步的见解 关于它们的生物学作用的可能机制。《知识》 通过这个项目获得的也与对 高LET辐射危害及高LET应用 肿瘤治疗中的放射治疗。

Exposure to ionizing radiation is mutagenic as demonstrated in plants, microorganisms, and mammalian cells. Little is known, however, about the processes underlying radiation-induced mutations in mammalian cells, and how the mutagenic process is influenced by the mode of radiation delivery and/or repair processes. Using rodent and human cells, the main objectives of the proposed research are to determine, (1) the dose dependencies for mutation induction by fission-spectrum neutrons from the JANUS reactor, compared to X- or Gamma-rays, and to estimate the relative biological effectiveness (RBE) for this end point; (2) the effect on mutation induction of fractionation and protraction of the radiation dose, for high and low LET radiations (JANUS neutrons, and X or gamma rays, respectively), and whether the mode of delivery indicates a role of repair mechanisms; (3) the effects of different modes of delivery of fission neutrons on the incidence of neoplastic transformation, for comparison with mutation induction to see whether these two end points are mechnistically related; and (4) the interactions of high and low LET radiations in induction of mutation and neoplastic transformation, in order to obtain further insights about the possible mechanisms of their biological actions. The knowledge acquired through this project is also relevant to the understanding of hazards from high LET radiations and to the application of high LET radiations in tumor therapy.