Possible role of inner-shell ionization phenomena in cell inactivation by heavy ions.
Possible role of inner-shell ionization phenomena in cell inactivation by heavy ions.
复制标题
内壳电离现象在重离子细胞失活中的可能作用。
DOI：
10.1080/09553009414550601
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发表时间：
1994
影响因子：
2.6
通讯作者：
B. Dutrillaux
中科院分区：
文献类型：
--
作者：
A. Chetioui;I. Despiney;L. Guiraud;L. Adoui;L. Sabatier;B. Dutrillaux
建立了由带电粒子引起的细胞失活的实验概率与细胞核DNA的重原子（C，N，O，P）中K-空位产生的计算概率之间的相关性。这两种现象显示出类似的依赖于入射粒子的线性能量转移（LET）。特别是对于低LET值，K横截面为各种入射离子有几乎相同的功能依赖于离子LET和较高的LET值，K横截面显示最大值，看起来像那些失活截面。这些特征是K电离现象的众所周知的特征，特别是在抛射电子的轨道速度附近发生抛射速度的概率最大。所观察到的相关性的意义进行了讨论，在沉积的能量和现有的实验结果在K-阈值的X射线吸收细胞灭活。我们考虑一种机制，它已经被唤起来解释这些光吸收实验，并假设K电离触发库仑爆炸和俄歇电子的能量耗散的双链断裂。然而，可以看出，K截面是重要的C，N和O原子，但可以忽略不计的P原子。因此，这里所考虑的损伤影响的是K光吸收实验中所涉及的原子之外的其他原子。关于随后的双链断裂和修复过程的损伤效率尚不清楚，但是人们可能怀疑可能由这种K离子化和细胞失活诱导的DNA平端之间的直接联系。
The existence of a correlation between experimental probabilities of cell inactivation by charged particles and calculated probabilities for K-vacancy production in heavy atoms (C, N, O, P) of the DNA of cell nuclei is established. Both phenomena display a similar dependence upon the linear energy transfer (LET) of incident particles. In particular for low LET values, K cross sections for various incident ions have nearly the same functional dependence on ion-LET and for higher LET-values, K cross sections display maxima which look like those of inactivation cross sections. These characteristics are well-understood features of the K-ionization phenomenon, in particular the maxima of probability occur for projectile velocities near orbital velocities of the ejected electrons. The meaning of the observed correlation is discussed in terms of deposited energy and in the light of existing experimental results on cell inactivation by X-ray absorption at K-threshold. We consider a mechanism which has already been evoked to explain these photo-absorption experiments and which assumes that a K ionization triggers a double-strand break by Coulomb explosion and energy dissipation of Auger electrons. However, it is seen that K cross sections are important for C, N and O atoms but negligible for P atoms. Thus, the lesion considered here affects other atoms than those involved in the K-photoabsorption experiments. The lesion efficiency with respect to subsequent double-strand breakage and repair processes is not yet known, however one may suspect a direct link between DNA blunt ends possibly induced by such K ionizations and cell inactivation.