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W Kroll

Publications and source records attributed to W Kroll.

68 records · Page 4Linked to original sources
PubMedDate not supplied

Cell cycle kinetics and metabolism of Ehrlich ascites tumor cells in the presence of chloramphenicol as inhibitor of mitochondrial protein synthesis.

In the presence of 150 micrograms/ml of chloramphenicol, viability (dye exclusion test) of Ehrlich ascites tumor cells is not severely affected within 48 h; however the number of dead cells increases above this concentration; more than 10 mg/ml render all of the cells dye-positive within a culture period of 24 h. With the highest concentration tested (25 mg/ml) cells begin to lose viability 8 h after beginning of treatment. In the first passage in the presence of the antibiotic, proliferation of the cells is reduced by about 50%; in the second passage cell growth was about 65% that of controls. As is shown by flow cytometric analysis and BrdU-H33258 technique of flow cytometry, the reduction of proliferation in the second passage is caused by retardation of cell cycle progression of about 8 h; in the third passage the cell cycle is delayed by further 8 h as compared to controls. On recultivation in the third passage in the absence of the inhibitor an increase of cell number of about 75% of controls was observed. Lactate production and glucose uptake of the cells were stimulated by the inhibitor by about 20%; oxygen consumption was 60% that of controls after 24 h; however the ATP/ADP ratio of chloramphenicol treated cells was in the range of controls. Over a time period of 24 h the incorporation of [2-14C]thymidine is reduced to 34 +/- 3%, incorporation of [2-14C]uridine was 88 +/- 4% that of controls, incorporation of [U-14C]lysine was not significantly affected by 150 micrograms/ml of chloramphenicol; the same was found for the uptake of [2-14C]-alpha-aminoisobutyric acid. Electron micrographs of chloramphenicol treated cells reveal a high amplitude of swelling of all mitochondria with a translucent appearance of the inner compartment. The mitochondrial membranes remain largely intact but the number of cristae is drastically reduced.

Animals↗
PubMedDate not supplied

Proliferation kinetics and metabolic features of in vitro grown Ehrlich ascites tumor cells in the presence of exogenous pyruvate.

The proliferation of in vitro grown Ehrlich ascites tumor cells is inhibited by pyruvate concentrations greater than 2 mM. In the presence of 4-5 mM pyruvate the growth is reduced to about 50%, in the presence of 20 mM to about 5-10%. Viability of the cells is not severely affected. Increase of DNA corresponds to the cell growth. On recultivation in pyruvate free standard medium, growth is nearly normal. Flow cytometric analyses of the proliferation kinetics of the cells in the presence of 20 mM pyruvate revealed a retardation of the passage of all phases of the cell cycle. No phase specific effects could be detected though the S- and G2M-phase are more afflicted than G1. The growth inhibition of EAT cells by pyruvate seems to depend on the presence of glucose. Exogenous pyruvate (greater than 1-2 mM) causes an activation of pyruvate dehydrogenase, a reduction of lactate production from glucose and a stimulation of lipid biosynthesis; the NAD/NADH ratio of the cells is reduced and a rise of glycolytic intermediates beyond glyceraldehyde-3-phosphate dehydrogenase is observed. Maximal activation of pyruvate dehydrogenase by non toxic concentrations of dichloroacetate is also accompanied by an inhibition of cell growth. It is suggested that an increase of glyceraldehyde-3-phosphate level and the changes in the redox state of the cells are of relevance for the inhibition of cell growth by pyruvate. 100-500 microM exogenous glyceraldehyde-3-phosphate strongly inhibited cell growth.

Animals↗
PubMedDate not supplied

Growth kinetics of the G2-phase of Ehrlich ascites tumor cells, separated from anaerobically treated asynchronous cultures.

Cell cycle progression of G2 fractions (75-80% G2 (4C) cells) from 8 h anaerobically cultured asynchronous hyperdiploid Ehrlich ascites tumor cells strain Karzel, separated by centrifugal elutriation, was studied after reaeration by flow cytometric methods, including the BrdU-H33258 technique and dual parameter measurements. Analyses of the growth kinetics demonstrated that one fraction of the cell population proceeds through a normal cell cycle (2C----4C) with a generation time of about 20 h. Another portion entered a new cycle (4C----8C) to form cells with a DNA content up to 8C; mono-, bi- and polynucleate cells could be detected. After 15 h aerobic recultivation of the anaerobically cultured G2 cells, a fraction containing 80-85% with a DNA content of greater than 4C was separated. On recultivation, these cells pass a 4C----8C division cycle with a generation time of about 10 h, and a G1 period of less than 4 h.

Aerobiosis↗
PubMedDate not supplied

Energy parameters, macromolecular synthesis and cell cycle progression of in vitro grown Ehrlich ascites tumor cells after inhibition of oxidative ATP synthesis by oligomycin.

In order to elucidate the significance of oxidative ATP production for the proliferation of Ehrlich ascites tumor cells, cell cycle progression, energy metabolism and macromolecular synthesis in the presence of oligomycin were studied. In the presence of the inhibitor (20 micrograms/ml), lactate production and glucose uptake of the cells increased by about 30-35% as compared to controls; oxygen consumption was maximally inhibited by 30-45% and could not further be reduced by higher concentrations of the inhibitor. ATP/ADP ratios of the oligomycin treated cells and control cells were not significantly different. In the first passage in the presence of oligomycin proliferation of the cells is reduced to about 50% that of controls; without severely affecting viability (dye exclusion test). In the second passage with oligomycin cell proliferation completely arrests. As was shown by flow cytometric analysis and BrdU-H33258 technique of flow cytometry, cells accumulate in the early S phase; division of cells which are in the S- and G2M compartment at the beginning of oligomycin treatment accounts for the increase of cell number in the first passage in the presence of oligomycin. On recultivation in the third passage in the absence of the inhibitor cells take up proliferation again; an increase of cell number of about 60% of controls was observed within 24 h. In the presence of oligomycin incorporation of [2-14C]thymidine is reduced to about 20% of the controls within 8 h, incorporation of [U-14C]lysine begins to slow down immediately after treatment with the inhibitor, the same is true for the incorporation of [2-14C]uridine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗