Combined effects of X irradiation and hyperthermia on CHO cells for various temperatures and orders of application.
Combined effects of X irradiation and hyperthermia on CHO cells for various temperatures and orders of application.
复制标题
X 辐射和热疗在不同温度和应用顺序下对 CHO 细胞的综合影响。
作者：
S. Sapareto;L. Hopwood;W. Dewey
CHO细胞在高温联合辐射处理下的存活表明，在照射前或照射后立即给予的热量使放射增敏剂s期细胞多于G1期细胞，因此导致每个阶段的绝对存活水平相似。G1期和S期辐照前施加的不同温度（42.0至45.5/sup 0/C）没有观察到效果的差异，当调整加热次数以获得单独加热的相同生存期（0.5至0.6）时。当辐照后加热和处理间隔时间增加时，G1期辐射损伤的修复与后续热损伤的相互作用发生在2小时的时间内。生存率从协同水平提高到独立水平，其动力学类似于分裂x射线剂量之间的修复。在本实验中，热处理温度分别为42.5或45.5/sup 0/C，并调整加热次数，以获得与单独加热相同的存活率（0.15）。当细胞在S期使用42.5或45.5/sup 0/C进行类似处理时（单热生存为0.2），从协同生存水平恢复的情况与G1期相似；然而，在两次治疗之间，生存期在120分钟内没有达到独立水平。当在辐照之前、期间或之后施加42.5或45.5/sup /C的相对亚致死热剂量时，在辐照期间和之后立即存在热量时，异步细胞存活的最大减少发生，可能是由于热量增加了辐射损伤的固定。与加热相比，放疗时间改变约5分钟，观察到存活时间的6倍差异。这种生存对方案变化的敏感性可能对联合使用热疗和放射治疗癌症有相当大的影响。«少
The survival of CHO cells to hyperthermic treatment combined with radiation indicates that heat given either immediately before or immediately after irradiation radiosensitizers S-phase cells more than G1 cells, thus resulting in similar absolute levels of survival for each phase. No difference in effect was observed for different temperatures (42.0 to 45.5/sup 0/C) applied before irradiation in either G1 or S when times of heating were adjusted to obtain the same survival (0.5 to 0.6) from heat alone. When heat was administered after irradiation and the time between treatments was increased, repair during G1 of radiation damage which interacted with subsequent heat damage occurred over a 2-hr period. Survival increased from a synergistic level to an independent level with kinetics similar to those seen for repair between split x-ray doses. For this experiment, the heat treatments were administered at either 42.5 or 45.5/sup 0/C with times of heating adjusted to obtain the same survival (0.15) from heat alone. When cells were treated similarly in S phase using either 42.5 or 45.5/sup 0/C (survival from heat alone was 0.2), recovery from a synergistic level of survival was similar to that observed in G1; however, survival did not reach an independent levelmore » by 120 min between treatments. When relatively sublethal heat doses at either 42.5 or 45.5/sup 0/C were applied either before, during, or after irradiation, the maximum reduction in survival of asynchronous cells occurred when heat was present during and immediately following irradation, presumably due to heat increasing the fixation of radiation damage. A sixfold difference in survival was observed with about a 5-min change in the timing of radiation with respect to heating. This sensitivity of survival to changes in protocol may have considerable implications in the combined use of hyperthermia and radiation for cancer therapy.« less