DNA DOUBLE-STRAND BREAK REPAIR DETERMINES THE RBE OF ALPHA-PARTICLES
DNA DOUBLE-STRAND BREAK REPAIR DETERMINES THE RBE OF ALPHA-PARTICLES
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DOI：
10.1080/09553008814552201
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发表时间：
1988-11-01
影响因子：
2.6
通讯作者：
BLOCHER, D
中科院分区：
文献类型：
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作者：
BLOCHER, D
用中性蔗糖梯度离心法研究了辐射诱导艾氏腹水癌细胞DNA双链断裂(DSB)。DSB的诱导与剂量呈线性关系，其频率为：ndsbmr-1D-1=(11.7±-)。2).时代。140kVX射线为10~(-12)Gy~(-1)，D~(-1)=(19.1±-)。4).时代。10-12Gy1，适用于3.4 MeV的241Am-α粒子。照射后的细胞在非生长条件下孵育可导致DSB的修复，在Trep=24 h后达到最大，经25GyX射线照射后，97%以上的DSB被修复。DSB残留量与剂量呈线性二次函数关系：nresmr-1=(0.0161.+-)。0.0008)。X线10-12Gy2D2，Nresmr-1=(1.2±-)。0.7)。10-12Gy1d+(0.105±-)。0.017)。α粒子10-12Gy2D2。因此，在细胞修复后，α粒子的RBE值从RBE=1.6.+-增加。0.4(DSB的诱导)至剂量依赖值RBE=2.7+-。0.4(100Gy.α粒子)至3.8.+-。1.2(10Gy.α粒子)用于残留DSB。从所提供的数据可以得出结论，残留的DSB是在X射线和α粒子照射后EATC繁殖能力丧失的主要原因。
Radiation-induced DNA double-strand breaks (dsb) were studied in Ehrlich ascites tumour cells (EATC) by sedimentation in neutral sucrose gradients at low centrifuge speed. Dsb induction was found to be linear with dose with a frequency of: ndsbmr-1 D-1 = (11.7 .+-. 2) .times. 10-12 Gy-1 for 140 kV X-rays and ndsbmr-1 D-1 = (19.1 .+-. 4) .times. 10-12 Gy-1 for 3.4 MeV 241Am-.alpha.-particles. Postirradiation incubation of cells under non-growth conditions leads to repair of dsb, reaching a maximum after trep = 24 h. More than 97 percent of dsb were repaired after an X-ray dose of 25 Gy. The number of residual dsb was found to be a linear-quadratic function of dose: nresmr-1 = (0.0161 .+-. 0.0008) .times. 10-12 Gy-2D2 for X-rays and nresmr-1 = (1.2 .+-. 0.7) .times. 10-12 Gy-1D + (0.105 .+-. 0.017) .times. 10-12 Gy-2D2 for .alpha.-particles. Thus, after cellular repair the RBE value of .alpha.-particles was incrased from RBE = 1.6 .+-. 0.4 (induction of dsb) to a dose-dependent value of RBE = 2.7 .+-. 0.4 (at 100 Gy .alpha.-particles) to 3.8 .+-. 1.2 (at 10 Gy .alpha.-particles) for residual dsb. From the data presented it is concluded that residual dsb are a major cause for loss of the reproductive capacity of EATC after irradiation with X-rays as well as .alpha.-particles.