Szekely J G, Raaphorst G P, Lobreau A U, Copps T P
Scan Electron Microsc. 1982(Pt 1):335-47.
Ultrastructural changes produced in cultured cells after irradiation by X-rays reflect the temporal development of the original lesions. Alterations in membrane structures, especially the plasma and nuclear membranes, are documented, supporting the suggestion that membrane and membrane-DNA attachment sites are relevant to radiation-induced cell killing. Alterations produced by the radiosensitizer diamide and by anisotonic salt treatments were also observed. Diamide, at 0.4 to 0.6 mmol/L, rapidly decreased the active uptake of K+ ions at the plasma membrane and produced clear, organelle-free regions of cytoplasm and distorted nuclei. Anisotonic NaCl treatment of mitotic cells swells chromosomes under both hypo- and hypertonic conditions, leaving the chromatin open to free-radical attack. In interphase, the cell is drastically shrunken during the first few minutes of hypertonic (1.5 mol/L NaCl) salt treatment, after which breaks and localized blebs appear at the plasma membrane, while the nucleus swells, leaving the chromatin in an open state. This process occurs more quickly at 37 degrees C than at room temperature (22 degrees C) and correlates with the relative radiosensitivity of cells treated at these temperatures.
X射线照射后培养细胞中产生的超微结构变化反映了原始损伤的时间发展过程。已记录到膜结构的改变，尤其是质膜和核膜，这支持了膜及膜与DNA附着位点与辐射诱导细胞死亡相关的观点。还观察到放射增敏剂二酰胺和非等渗盐处理所产生的变化。0.4至0.6 mmol/L的二酰胺能迅速降低质膜上K+离子的主动摄取，并产生清晰的、无细胞器的细胞质区域以及变形的细胞核。对有丝分裂细胞进行非等渗NaCl处理，在低渗和高渗条件下都会使染色体膨胀，使染色质易于受到自由基攻击。在间期，高渗（1.5 mol/L NaCl）盐处理的最初几分钟内细胞会急剧收缩，之后质膜出现断裂和局部泡状突起，而细胞核膨胀，使染色质处于开放状态。此过程在37℃比在室温（22℃）下发生得更快，并且与在这些温度下处理的细胞的相对放射敏感性相关。
