Maisin J R, Wambersie A, Gerber G B, Mattelin G, Lambiet-Collier M, De Coster B, Gueulette J
Biology Department, C.E.N./S.C.K., Mol, Belgium.
Radiat Res. 1988 Feb;113(2):300-17.
C57Bl Cnb mice were exposed to single or fractionated d(50)+Be neutrons or 137Cs gamma-ray exposure at 12 weeks of age and were followed for life-shortening and disease incidence. The data were analyzed by the Kaplan-Meier procedure using as criteria cause of death and possible cause of death. Individual groups were compared by a modified Wilcoxon test according to Hoel and Walburg, and entire sets of different doses from one radiation schedule were evaluated by the procedure of Peto and by the Cox proportional hazard model. No significant difference was found in life-shortening of C57Bl mice between a single gamma and neutron exposure. Gamma fractionation was clearly less effective in reducing survival time than a single exposure. On the contrary, fractionation of neutrons was slightly although not significantly more effective in reducing life span than a single exposure. Life-shortening appeared to be a linear function of dose in all groups studied. The data on causes of death show that malignant tumors, particularly leukemias including thymic lymphoma, and noncancerous late degenerative changes in lung were the principal cause of life-shortening after a high single gamma exposure. Exposure delivered in 8 fractions 3 h apart was more effective in causing leukemias and all carcinomas and sarcomas than one delivered in 10 fractions 24 h apart or in a single session. Following a single neutron exposure, leukemias and all carcinomas and sarcomas appeared to increase somewhat more rapidly with dose than after gamma irradiation. No significant difference in the incidence of leukemias and all carcinomas and sarcomas was noted between a single and a fractionated neutron exposure.
将12周龄的C57Bl Cnb小鼠暴露于单次或分次的d(50)+铍中子或137铯γ射线照射下，并对其进行寿命缩短和疾病发病率的跟踪。使用死亡原因和可能的死亡原因作为标准，通过Kaplan-Meier程序对数据进行分析。根据Hoel和Walburg的方法，通过改良的Wilcoxon检验对各个组进行比较，并通过Peto程序和Cox比例风险模型对一个辐射方案的不同剂量的整个数据集进行评估。在单次γ射线和中子照射之间，未发现C57Bl小鼠的寿命缩短有显著差异。γ射线分次照射在缩短生存时间方面明显不如单次照射有效。相反，中子分次照射在缩短寿命方面虽然没有显著差异，但比单次照射略有效。在所研究的所有组中，寿命缩短似乎是剂量的线性函数。死亡原因的数据表明，恶性肿瘤，特别是包括胸腺淋巴瘤在内的白血病，以及肺部的非癌性晚期退行性变化是单次高剂量γ射线照射后寿命缩短的主要原因。每隔3小时分8次照射比每隔24小时分10次照射或单次照射更易引发白血病以及所有的癌和肉瘤。单次中子照射后，白血病以及所有的癌和肉瘤的发病率似乎比γ射线照射后随剂量增加得更快。单次和分次中子照射之间，白血病以及所有的癌和肉瘤的发病率没有显著差异。
