Studies on nucleoli of leukemic agranulocytes and plasmacytes in multiple myeloma

Cell kinetics of irradiated experimental tumors: relationship between the proliferating and the nonproliferating pool

The role of nonproliferating cells in tumor regeneration has been studied after subcurative doses of low L.E.T. irradiation. Radiation was applied in a single dose at three different levels; 0-47, 0-94 and 1-88 krad. Studies included estimation of the absolute number of cells per tumor, differential cell counts, and autoradiographic determination of kinetic variables, employing transplantable mouse mammary adenocarcinoma DBAH. Quantitative changes of morphologically defined proliferating and nonproliferating cell pools were followed at different time intervals after irradiation. Irradiation resulted in reduction of the number of cells in both pools, with apparent sparing of nonproliferating cells. The regenerative period started with a gradual increase in the number of cells in the proliferating pool, whereas the number of cells in the nonproliferating pool continued to fall in tumors irradiated with 0-94 and 1-88 krad. In the late phase of tumor regrowth, the increasing number of cells in the non proliferating pool corresponded to its replenishment by cell transition from the proliferating pool. In an effort to clarify whether cell transition from the nonproliferating to the proliferating pool may take place during the regrowth of radiation perturbed tumors, cell loss rates from both pools were estimated using experimental data. In addition to cell loses from the tumor as a whole, the 'net loss rate' of the nonproliferating pool reflects the rate of cell transition from the nonproliferating to the proliferating pool, minus the rate of transition in the opposite direction. A similar definition applies to cell loss rates from the proliferating pool. The results showed: (1) high losses in both pools, with excess losses in the proliferating during the early phase after irradiation; (2) in the early stage of regrowth after irradiation, the cell net loss rate f-or the nonproliferating pool increased, in contrast to the behavior of cell loss rate for the proliferating pool and the average cell loss rate for the tumor as a whole; (3) in the late stage of regrowth a decrease in net loss rate for the nonproliferating pool reflects the excess production of nonproliferating cells over control tumors. These results suggest that cell transition from the nonproliferating to the proliferating pool takes place at the beginning of tumor regrowth after subcurative single-dose irradiation.

Nuclear division in the ameboflagellate Adelphamoeba galeacystis

Nuclear division is synchronized cultures of the ameoboflagellate Adelphamoeba galecystis has been described. Division in this organism is typically promitotic. It occurs within an intact nuclear membrane and is characterized by the persistence of the nucleolus and its transformation into 2 polar masses. The nucleolus is stained with pyronin-Y by the methyl green pyronin-Y technic, and with Heidenhain's hematoxylin, but is unstained by the Feulgen reaction. The reaction with these stsins is removed after digestion of the nucleolus by ribonuclease. During mitosis the nucleolus undergoes an orderly series of vacuolizations before forming the polar masses. The chromatin is Feulgen positive, stains with methyl green by the methyl green pyronin-Y technic and undergoes a series of characteristic changes during the division process. Synchronizationof amebae grown on coverglasses was accomplished by transfer of cells from 30 to 38.5 C for a period of 100 min. A temporal sequence of nucleolar and chromatin participation in the nuclear division of this organism is suggested.

Nucleolar size in benign and malignant plasma cell proliferation;

Nucleolar and nuclear size of bone marrow plasma cells has been studied in 26 cases of myeloma, 19 of benign essential monoclonal gammapathy (BEMG) and 9 without an M-component. Bone marrow smears were Feulgen-stained to visualize nucleoli and nuclei. Nucleolar area, nuclear area and the ratio nucleolar area/nuclear area were calculated. The myeloma group differed from the other two groups in having plasma cells with larger nucleoli, larger nuclei and an increased ratio nucleolar area/nuclear area. No difference was found between the BEMG group and the cases without an M-component. In some cases--in which the absence of osteolytic lesions at X-ray examination, a low plasma cell percentage in bone marrow smears or a low M-component concentration initially made the diagnosis of myeloma uncertain--the observation of enlarged nucleoli could help to establish the diagnosis. Three cases were observed in which the onset of myeloma was preceded by a long period of essentially unchanged M-component concentration. In these cases a sudden increase of M-component concentration was accompanied by an increase of mean nucleolar size of bone marrow plasma cells.