OXYGEN DIFFUSION INTO MAMMALIAN-CELLS FOLLOWING ULTRAHIGH DOSE-RATE IRRADIATION AND LIFETIME ESTIMATES OF OXYGEN-SENSITIVE SPECIES
OXYGEN DIFFUSION INTO MAMMALIAN-CELLS FOLLOWING ULTRAHIGH DOSE-RATE IRRADIATION AND LIFETIME ESTIMATES OF OXYGEN-SENSITIVE SPECIES
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DOI：
10.2307/3574801
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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：
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作者：
LING, CC;MICHAELS, HB;PETERSON, EC
基于对高强度辐射单脉冲照射的培养物[中国仓鼠卵巢]CHO细胞的断裂存活曲线的观察，利用先前开发的细菌系统双脉冲技术研究了O2扩散到这些细胞中的动力学。将两个高强度电子脉冲（每个持续时间为3 ns）递送至与已知浓度的O 2 （通常约0.44% O 2 ）平衡的单层CHO细胞。第一个脉冲的剂量足以通过放射化学方式耗尽细胞内的 O2，并且在类似的第二个脉冲之前有一个准确已知的脉冲间时间，从 10-6 秒到 60 秒不等。通过比较细胞对延时的第二个脉冲的反应与各种已知 O2 浓度下的单脉冲的反应，推断出脉冲间时间期间扩散到细胞中关键部位的氧气的相对浓度。实验获得的O2扩散曲线可以通过使用O2在水中的扩散系数为2×的一维扩散方程的解来描述。 10-5 cm2/s，关键位置的平均深度为 4 μm，大约对应于细胞半径。 O2 扩散曲线表明大量 O2 扩散到这些位点。 3次。 10-3秒。这可以解释为辐射引起的 O2 依赖性损伤的平均寿命的上限，因为否则不会观察到破坏的生存曲线。
Based on the observation of breaking survival curves for cultures [Chinese hamster ovary] CHO cells irradiated by single pulses of high-intensity radiation, the kinetics of O2 diffusion into these cells was studied using the double-pulse technique developed previously with bacterial systems. Two high-intensity electron pulses, each of 3 ns duration, were delivered to a monolayer of CHO cells in equilibrium with a known concentration of O2 (typically .apprx. 0.44% O2). The 1st pulse was of sufficient dose to deplete the intracellular O2 radiochemically and preceded a similar 2nd pulse by an accurately known interpulse time, variable from 10-6 to 60 s. The relative concentration of oxygen diffusing to critical sites in the cell during the interpulse time was inferred by comparing the cellular response to the time-delayed 2nd pulse with that to single pulses under various known O2 concentrations. The O2 diffusion curve obtained experimentally can be described by the solution of a one-dimensional diffusion equation using the O2 diffusion coefficient in water of 2 .times. 10-5 cm2/s and an average depth of the critical sites of 4 .mu.m corresponding approximately to a cell radius. The O2 diffusion curve indicates that a significant amount of O2 diffused to these sites by .apprx. 3 .times. 10-3 s. This can be interpreted as an upper limit to the average life-time of the radiation-induced O2 dependent damage since otherwise breaking survival curves would not have been observed.