Goodwin E H, Bailey S M, Chen D J, Cornforth M N
Los Alamos National Laboratory, Life Sciences Division, Los Alamos, NM 87545, USA.
Adv Space Res. 1996;18(1-2):93-8. doi: 10.1016/0273-1177(95)00795-g.
The influence of track structure on chromosome damage and cell inactivation are being investigated. Plateau-phase normal human fibroblast cultures were irradiated with gamma rays, and He, Ne and Ar ions. Particle velocities were chosen so that all beams had an LET of 120 keV/micrometer. In this constant-LET experimental design, the radial distribution of excitations and ionizations about the particle track is the most significant variable. Using premature chromosome condensation, chromatin breaks were measured at two time points, promptly after irradiation and after a prolonged incubation to allow for repair. These measurements give an indication of both initial chromosomal damage and also residual damage that is either not repaired or is misrepaired. Survival was measured under the same conditions. Results indicate that the RBEs for both cell inactivation and, to a lesser extent, chromosome damage decrease as particle energy increases.
正在研究轨道结构对染色体损伤和细胞失活的影响。用伽马射线、氦离子、氖离子和氩离子对处于平台期的正常人成纤维细胞培养物进行辐照。选择粒子速度，使所有束流的线性能量传递（LET）均为120 keV/微米。在这种恒定LET的实验设计中，围绕粒子轨道的激发和电离的径向分布是最重要的变量。利用早熟染色体凝聚，在两个时间点测量染色质断裂情况，一个是在辐照后立即测量，另一个是在长时间孵育以进行修复后测量。这些测量结果既显示了初始染色体损伤情况，也显示了未修复或错误修复的残余损伤情况。在相同条件下测量细胞存活率。结果表明，随着粒子能量增加，细胞失活以及程度较轻的染色体损伤的相对生物效应（RBE）均降低。
