Wheeler K T, Wallen C A
Br J Cancer Suppl. 1980 Apr;4:299-303.
The influence fo growth rate, location, size and PLD recovery on the cellular radiosensitivity, the tumour response (increase in life-span) and the relationship between these two end points was studied using two sublines of the 9L rat brain tumour, designated 9L/Ro and 9L/SF. The median day of death of rats bearing the intracerebral (i.c.) 9L/Ro tumours was 16-18 days; for i.c. 9L/SF tumours it was 23-25 days. The doubling time of 9L/Ro cells was slightly faster than that for 9L/SF cells both in culture and in the brain. The cellular radiosensitivity of both i.c. tumour cell sublines was identical when measured immediately after irradiation by an in vitro colony formation assay. However, subcutaneous (s.c.) 9L/Ro tumour cells were more resistant (D0 = 332 rad cf 180 rad). There was no evidence of a substantial hypoxic fraction in either site. When i.c. 9L/Ro and 9L/SF tumours of similar size were treated with fractionated doses of BCNU, X-rays or combinations of the two, the responses of the two tumours were essentially identical. The rate of recovery from radiation-induced potentially lethal damage (PLD) was identical in the two sublines and the two sites, although the extent of the PLD recovery was apparently greater in s.c. tumours. Increase in life-span of rats bearing i.c. 9L/Ro tumours appeared to be correlated with the tumour cell kill measured after completion of PLD recovery rather than with the tumour cell kill determined immediately after irradiation.
利用9L大鼠脑肿瘤的两个亚系（分别命名为9L/Ro和9L/SF），研究了生长速率、位置、大小和潜在致死性损伤（PLD）修复对细胞放射敏感性、肿瘤反应（寿命延长）以及这两个终点之间关系的影响。携带脑内（i.c.）9L/Ro肿瘤的大鼠的中位死亡天数为16 - 18天；对于脑内9L/SF肿瘤，中位死亡天数为23 - 25天。9L/Ro细胞在培养中和脑内的倍增时间均略快于9L/SF细胞。通过体外集落形成试验在照射后立即测量时，两个脑内肿瘤细胞亚系的细胞放射敏感性相同。然而，皮下（s.c.）9L/Ro肿瘤细胞更具抗性（D0 = 332拉德，而9L/SF为180拉德）。在两个部位均未发现大量缺氧部分的证据。当用分次剂量的卡莫司汀（BCNU）、X射线或两者组合治疗大小相似的脑内9L/Ro和9L/SF肿瘤时，两种肿瘤的反应基本相同。两个亚系和两个部位从辐射诱导的潜在致死性损伤（PLD）中的修复速率相同，尽管皮下肿瘤中PLD修复的程度明显更大。携带脑内9L/Ro肿瘤的大鼠寿命延长似乎与PLD修复完成后测量的肿瘤细胞杀伤相关，而非与照射后立即确定的肿瘤细胞杀伤相关。
