OXYGEN SENSITIZATION OF CHO CELLS AT ULTRAHIGH DOSE-RATES - PRELUDE TO OXYGEN DIFFUSION STUDIES
OXYGEN SENSITIZATION OF CHO CELLS AT ULTRAHIGH DOSE-RATES - PRELUDE TO OXYGEN DIFFUSION STUDIES
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DOI：
10.2307/3574800
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发表时间：
1978-01-01
影响因子：
3.4
通讯作者：
PETERSON, EC
中科院分区：
文献类型：
--
作者：
MICHAELS, HB;EPP, ER;PETERSON, EC
培养的[中国仓鼠卵巢] CHO细胞对高剂量率（约1011拉德/秒）辐射，作为衡量的菌落形成能力，已被研究在不同的O2浓度与单电子脉冲的持续时间为3纳秒。为这些实验设计了薄层技术，以允许细胞与周围含O2气体快速平衡，并确保细胞群的任何部分都不被屏蔽以免受相对低能量电子（平均能量，apx. 450 keV），从而消除了影响存活分数的伪影的可能性。使用量热、电荷测量和热释光技术的组合进行剂量测定。在0.44%O_2浓度下，观察到存活曲线的断裂行为，其与辐射脉冲引起的细胞内O_2的辐解耗尽行为雅阁。剂量大于断点剂量的敏感性遵循缺氧反应，明显不同于观察到的细胞时，在相同的几何形状下，在相同的气体中，在常规剂量率照射。在0- 0.7%的O2浓度范围内，折点剂量近似呈线性。这些结果与最近观察到的哺乳动物细胞在高强度照射条件下的反应是一致的，并为双脉冲实验的设计提供了基础。
The response of cultured [Chinese hamster Ovary] CHO cells to ultrahigh dose rate (.apprx. 1011 rad/s) radiation, as measured by colony-forming ability, has been studied under various O2 concentrations with single electron pulses of 3 ns duration. A thin-layer technique was designed for these experiments to permit rapid equilibration of the cells with the ambient O2 containing gas and to ensure that no segments of the cell population were shielded from the relatively low energy electrons (average energy, .apprx. 450 keV), thus eliminating the possibility of artifacts influencing surviving fraction. Dosimetry was performed using a combination of calorimetric, charge-measuring and thermoluminescent techniques. At a concentration of 0.44% O2 breaking behavior of the survival curve was observed in accord with the radiolytic depletion of intracellular O2 by the radiation pulse. The sensitivity for doses greater than the breakpoint dose followed an anoxic response, clearly different from that observed when the cells were irradiated at conventional dose rates in the same gas under the identical geometry. The breakpoint dose was approximately linear over the O2 concentration range 0-0.7%. These results are consistent with recent observations of mammalian cell response under high-intensity irradiation conditions and provide a basis for the design of a double-pulse experiment.