Neutron RBEs and the radiosensitive target for mouse immature oocyte killing.
Neutron RBEs and the radiosensitive target for mouse immature oocyte killing.
复制标题
中子 RBE 和杀死小鼠未成熟卵母细胞的放射敏感靶标。
作者：
T. Straume;R. Dobson;T. C. Kwan
用不同剂量的~（252）Cf裂变辐射、0.43-MeV或15-MeV中子或~（60）Co γ射线对小鼠高度放射敏感的未成熟卵母细胞进行体内照射。中子和γ射线的卵母细胞存活率的比较表明，中子RBE杀死这些重要的细胞不达到高值（30-50或更多），在低剂量观察到的其他几个生物学终点。相反，中子在杀死这些极其敏感的小鼠卵母细胞方面与伽马射线的有效性几乎没有区别。对于0.43 MeV中子，从拟合的存活曲线得到的RBE在0.1 rad时仅达到1.7。对于15 MeV中子，在任何测试剂量下（最低，4.5 rad），它们与1没有显著差异。对于252 Cf裂变中子（E = 2.15 MeV），RBE介于0.43 MeV和15 MeV中子的RBE之间。对于所有的中子能量测试，RBE是特别低的青少年时期，当小鼠未成熟的卵母细胞是特别放射敏感的时间。然而，在出生前暴露，当这些细胞不容易被杀死，更高，更常见的RBE被发现。小鼠未成熟卵母细胞的致死目标的最小尺寸，估计从0.43 MeV中子和微剂量值的灭活常数，大于细胞核，但不大于细胞。这一点和相关的分析考虑表明，在这些特定的卵母细胞中的超敏目标是质膜，这一发现是在极好的雅阁从其他实验中使用不同的，对比辐射和剂量输送（加速Si 14+离子，γ射线，β射线从3 HOH相比，从[3 H]胸苷）的结果。
The highly radiosensitive immature oocytes of mice were irradiated in vivo with graded doses of 252Cf fission radiation, 0.43- or 15-MeV neutrons, or 60Co gamma rays. Comparisons of oocyte survival for neutrons and for gamma rays demonstrate that neutron RBEs for the killing of these important cells do not reach the high values (30-50 or more) at low doses observed for several other biological end points. Rather, neutrons differ little in effectiveness from gamma rays in killing these extremely sensitive murine oocytes. For 0.43-MeV neutrons, RBEs obtained from fitted survival curves reach only 1.7 at 0.1 rad. For 15-MeV neutrons, they are not significantly different from 1 at any dose tested (lowest, 4.5 rad). For 252Cf fission neutrons (E = 2.15 MeV), RBEs are intermediate between those for 0.43- and 15-MeV neutrons. For all neutron energies tested, the RBEs are particularly low in the juvenile period, a time when murine immature oocytes are especially radiosensitive. With exposure just prior to birth, however, when these cells are much less easily killed, higher, more usual RBEs are found. The minimum size of the lethality target in mouse immature oocytes, estimated from the inactivation constant for 0.43-MeV neutrons and microdosimetric values, is larger than the nucleus but not larger than the cell. This and related analytical considerations suggest that the hypersensitive target in these particular oocytes is the plasma membrane, a finding which is in excellent accord with results from other experiments using different, contrasting radiations and dose deliveries (accelerated Si14+ ions, gamma rays, and beta rays from 3HOH compared with those from [3H]thymidine).
对 BEIR III 报告躯体效应部分的评论。
影响因子：
3.4
作者：
Rossi,HH
通讯作者：
Rossi,HH