van Rensburg E J, Louw W K, Izatt H, van der Watt J J
Int J Radiat Biol Relat Stud Phys Chem Med. 1985 Jun;47(6):673-9. doi: 10.1080/09553008514550911.
Enriched human B- and T-lymphocyte subpopulations were isolated by means of a Percoll step gradient centrifugation procedure. 60Co gamma-irradiation dose-response curves for these subpopulations were obtained by applying a modified nucleoid sedimentation technique, which was also employed for the determination of the superhelical content by means of ethidium bromide intercalation. Although a similarity in the average superhelical density of B- and T1-lymphocytes was shown, B-lymphocytes exhibited a more pronounced reduction in sedimentation ratio, suggesting a higher radiosusceptibility than the T1-lymphocytes. By applying the single hit kinetics of the target theory to the dose-response curves, an estimation of the supercoil domain sizes was made: B- cells, 5.5 X 10(9), 1.78 X 10(9) and 7.78 X 10(8) D; T-cells, 4.55 X 10(9), 1.75 X 10(9) and 7.67 X 10(8) D. The differences in radiosensitivity of lymphocyte subpopulations can not, therefore, be entirely ascribed to differences in DNA superstructure.
通过Percoll不连续梯度离心法分离富集的人B淋巴细胞和T淋巴细胞亚群。采用改良的核仁沉降技术获得这些亚群的60Coγ射线照射剂量反应曲线，该技术也用于通过溴化乙锭嵌入法测定超螺旋含量。虽然B淋巴细胞和T1淋巴细胞的平均超螺旋密度相似，但B淋巴细胞的沉降率下降更为明显，表明其放射敏感性高于T1淋巴细胞。通过将靶理论的单次打击动力学应用于剂量反应曲线，对超螺旋结构域大小进行了估计：B细胞为5.5×10(9)、1.78×10(9)和7.78×10(8)D；T细胞为4.55×10(9)、1.75×10(9)和7.67×10(8)D。因此，淋巴细胞亚群放射敏感性的差异不能完全归因于DNA超结构的差异。
