Schultze B, Kellerer A M, Maurer W
Cell Tissue Kinet. 1979 Jul;12(4):347-59. doi: 10.1111/j.1365-2184.1979.tb00159.x.
Mean transit times as well as variances of the transit times through the individual phases of the cell cycle have been determined for the crypt epithelial cells of the jejunum of the mouse. To achieve this the fraction of labelled mitoses (FLM) technique has been modified by double labelling with [3H] and [14C]thymidine. Mice were given a first injection of [3H]thymidine, and 2 hr later a second injection of [14C]thymidine. This produces a narrow subpopulation of purely 3H-labelled cells at the beginning of G2-phase and a corresponding subpopulation of purely 14C-labelled cells at the beginning of the S-phase. When these two subpopulations progress through the cell cycle, one obtains FLM waves of purely 3H- and purely 14C-labelled mitoses. These waves have considerably better resolution than the conventional FLM-curves. From the temporal positions of the observed maxima the mean transit times of the cells through the individual phases of the cycle can be determined. Moreover one obtains from the width of the individual waves the variances of the transit times through the individual phases. It has been found, that the variances of the transit times through successive phases are additive. This indicates that the transit times of cells through successive phases are independently distributed. This statistical independence is an implicit assumption in most of the models applied to the analysis of FLM curves, however there had previously been no experimental support of this assumption. A further result is, that the variance of the transit time through any phase of the cycle is proportional to the mean transit time. This implies that the progress of the crypt epithelial cells is subject to an equal degree of randomness in the various phases of the cycle.
已测定小鼠空肠隐窝上皮细胞在细胞周期各个阶段的平均转运时间以及转运时间的方差。为实现这一目的，通过用[3H]和[14C]胸苷进行双重标记，对标记有丝分裂分数（FLM）技术进行了改进。给小鼠首次注射[3H]胸苷，2小时后第二次注射[14C]胸苷。这在G2期开始时产生了一个狭窄的纯3H标记细胞亚群，在S期开始时产生了一个相应的纯14C标记细胞亚群。当这两个亚群在细胞周期中进展时，可获得纯3H和纯14C标记有丝分裂的FLM波。这些波的分辨率比传统的FLM曲线要好得多。根据观察到的最大值的时间位置，可以确定细胞在周期各个阶段的平均转运时间。此外，从各个波的宽度可以获得细胞在各个阶段转运时间的方差。已发现，细胞在连续阶段的转运时间方差是可加的。这表明细胞在连续阶段的转运时间是独立分布的。这种统计独立性是应用于FLM曲线分析的大多数模型中的一个隐含假设，然而此前没有该假设的实验支持。另一个结果是，细胞在周期任何阶段的转运时间方差与平均转运时间成正比。这意味着隐窝上皮细胞在周期的各个阶段受到同等程度的随机性影响。
