A Comparison of Analytical Methods for the Generation Time of Cultured Human Myeloma Cell Line, KMM-1
The generation time (GT) of a human myeloma cell line (KMM-1) producing λ-type Bence-Jones protein1) was analyzed by the following methods; calculation from the growth curve, autoradiographic analyses of continuous 3H-thymidine labeling and of a fraction of labeled mitoses, the sister chromatid exchange method, time-lapse cinemicrography, and flow cytometric measurement. The GTs obtained by each method differed considerably. The GT calculated from the cell growth curve was 29.3 hr, while those analyzed by other methods were as follows: 16.6 hr by a fraction of labeled mitoses, 22.9 hr by sister chromatid exchange, and 26.4 hr by time-lapse cinemicrography, and 18 to 20 hr by flow cytometric analysis. The mean GT of the cultured myeloma cells, when averaged from these results, was 22.8 hr. The reasons for differences in the GTs obtained by these different analytical methods were suggested in Discussion.