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

Paraproteinemia in a Patient with Acute Myelogenous Leukemia Derived from the Myelodysplastic Syndrome : A Case Report

Severe paraproteinemia was found in a 75-year-old female with acute myelogenous leukemia (AML) derived from refractory anemia with an excess of blasts, a type of the myelodysplastic syndrome (MDS). Immunoglobulin G-κ and G-λ paraproteins had increased in accordance with the proliferation of myeloblasts in her bone marrow. When the diagnosis of AML was made, a severe bleeding tendency and disturbance of consciousness due to the hyperviscosity syndrome were noted, although there was no significant increase in plasma cells in her bone marrow. An ultrasonogram disclosed multiple hyperechoic nodular lesions in the spleen. Cytoreductive therapy for AML was begun after plasma exchange, but she died of acute renal failure, subarachnoid hemorrhage, and the disseminated intravascular coagulation syndrome. Autopsy findings revealed clusters of plasma cells in the spleen and lymph nodes. The possibility that this coexistant paraproteinemia and AML were related to the evolution of a transformed clone in MDS is discussed