Lee Y J, Ducoff H S
Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan 48072.
Radiat Res. 1989 Jan;117(1):158-62.
Shortly after gamma irradiation, flour beetles exhibited a decline in resistance to oxygen toxicity. Then, about 2 weeks after irradiation, the 50% lethal dose (LD50) exposure time in pure oxygen was much greater than that of nonirradiated beetles, and this enhanced resistance persisted for about 6 months. The magnitude of the enhancement was a function of dose, decreased with increasing age at irradiation, and was modified by radiation factors. Both dose protraction and dose fractionation reduced the development of oxygen resistance to approximately the same degree that it reduced acute radiation lethality. This suggests that both the initial sensitization and the later enhancement of resistance are correlated with the residual biological damage rather than with the physical dose or initial damage.
在伽马射线照射后不久，赤拟谷盗对氧毒性的抗性就出现下降。然后，在照射后约2周，纯氧环境下的50%致死剂量（LD50）暴露时间比未照射的甲虫长得多，且这种增强的抗性持续了约6个月。增强的幅度是剂量的函数，随照射时年龄的增加而降低，并受到辐射因素的影响。剂量延长和剂量分割对氧抗性发展的降低程度，与它们降低急性辐射致死率的程度大致相同。这表明，最初的敏感性和后来抗性的增强都与残余生物损伤相关，而非与物理剂量或初始损伤相关。
