Franken N, Vanbree C, Streefkerk J, Kuper I, Rodermond H, Kipp J, Haveman J, Barendsen G
UNIV AMSTERDAM,ACAD MED CTR,DEPT MED ONCOL,NL-1100 DE AMSTERDAM,NETHERLANDS.
Oncol Rep. 1997 Sep-Oct;4(5):1073-6. doi: 10.3892/or.4.5.1073.
To investigate radiosensitization by halogenated pyrimidines in human cells, SW-1573 lung tumor cells were grown in absence or presence of 4 mu M of iododeoxyuridine (IdUrd). Cell survival after irradiation with gamma-rays from a Cs-137 source with single doses up to 8 Gy, was determined by clonogenic assay, Radiosensitization by IdUrd was observed in both exponentially growing and plateau phase cells. Linear-quadratic analyses of the radiation survival curves demonstrated that radiosensitization was mainly expressed by an increase of the value of alpha (determining the initial slope of the survival curve) which can be interpreted as an enhancement of fixation of potentially lethal damage (PLD). The value of beta (determining the curvature of the survival curve), which might be attributed to enhanced interaction or to fixation of sublethal damage (SLD), was not influenced. In view of clinical applications of IdUrd it is of interest that radiosensitization has its main effect in the low dose region of the cell survival curve, described by the linear term alpha D.
为了研究卤代嘧啶对人细胞的放射增敏作用，将SW - 1573肺肿瘤细胞分别在不存在或存在4 μM碘脱氧尿苷（IdUrd）的情况下培养。通过克隆形成试验测定用来自Cs - 137源的γ射线单次照射剂量高达8 Gy后的细胞存活率。在指数生长期和平稳期细胞中均观察到IdUrd的放射增敏作用。对辐射存活曲线的线性二次分析表明，放射增敏主要表现为α值（决定存活曲线的初始斜率）增加，这可解释为潜在致死性损伤（PLD）固定的增强。β值（决定存活曲线的曲率）可能归因于增强的相互作用或亚致死性损伤（SLD）的固定，其不受影响。鉴于IdUrd的临床应用，放射增敏在细胞存活曲线的低剂量区域（由线性项αD描述）具有主要作用这一点很有意思。
