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1Author    Reiner Merz, Monika Löffler, Friedhelm SchneiderRequires cookie*
 Title    Further Investigations on the /?-Nitrophenylphosphatase Activity of Intact Ehrlich Ascites Tumor Cells  
 Abstract    The substrate specificity and the effects of nucleotides and SH-blocking agents on the p-nitro-phenylphosphatase activity of intact Ehrlich ascites tumor cells (EAT) cells were studied. DL-ß-Glycerophosphate, o-phosphoethanolamine, cholinephosphate, glucose-6-phosphate, o-carboxyphenyl-phosphate,, phosphoenolpyruvate and AMP were not attacked by intact cells. ATP > GTP > UTP > PPj > pNPP were cleaved with decreasing velocity. A stimulation of the cleavage of p-NPP by the following nucleotides was observed with decreasing effectivity: ATP > ADP > GTP > UTP; AMP was ineffective. The phosphatase activity was not affected by malate, tartrate and glutathion disulfide. The SH blocking agents diamide and thimerosal were more effective in­ hibitors of the pNPPase than of the ATPase activity, whereas the hydrolysis of ATP is more affected by the ATP analog adenylylimidodiphosphate. The present data are best compatible with a double headed enzyme: Both active sites interact with ATP, only one is active against p-NPP and sensitive against SH-blocking agents. 
  Reference    Z. Naturforsch. 33c, 227 (1978); received January 23 1978 
  Published    1978 
  Keywords    Phosphatase Activity, Ehrlich Ascites Tumor Cells, SH Blocking Agents 
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 TEI-XML for    default:Reihe_C/33/ZNC-1978-33c-0227.pdf 
 Identifier    ZNC-1978-33c-0227 
 Volume    33 
2Author    Regina Teschner, Stefan Postius, M. Onika Löffler, Friedhelm SchneiderRequires cookie*
 Title    Cell Proliferation and Metabolism of Ehrlich Ascites Tumor Cells Grown in Chemically Defined Albumin Medium for Several Passages  
 Abstract    Cell proliferation, cell cycle distribution, viability, uptake o f ar-aminoisobutytic acid, cyclo leucine and 2-deoxyglucose as well as DNA, RNA and protein synthesis of Ehrlich ascites tumor cells grown in suspension culture over three passages in serum free nutrient medium supplemented with 1 -2 % bovine serum albumin (Cohn fraction V, Serva) were measured and compared to cells grown in medium supplemented with 15% horse serum. At the end of the fourth passage in vitro, that is the third passage in serum free albumin medium, the growth o f the cells is reduced to about 1 0 % of the controls, accumulation of the cells in G 2 is delayed and the number o f dead cells rises to 30%. The transport rates o f a-aminoisobutyric acid and o f 2-deoxyglucose slowly decrease while the up­ take of cycloleucine shows a more complex behaviour in albumin medium. Incorporation o f thy­ midine and leucine into the cells corresponds to the growth rate, while the incorporation o f uridi­ ne in normal as well as in albumin medium exhibits different pattern. The present experiments demonstrate, that it may be possible to preserve this cells in a fairly "physiological" state during two passages in albumin medium. 
  Reference    Z. Naturforsch. 35c, 117 (1980); received October 29 1979 
  Published    1980 
  Keywords    Albumin Medium, Cell Growth, Ehrlich Ascites Tumor Cells, Metabolism 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0117.pdf 
 Identifier    ZNC-1980-35c-0117 
 Volume    35 
3Author    KarlA. Reiffen, Monika Löffler, Friedh SchneiderRequires cookie*
 Title    The Effect of Glucosone on the Proliferation and Energy Metabolism of in vitro Grown Ehrlich Ascites Tumor Cells  
 Abstract    1) Proliferation and energy metabolism of in vitro grown Ehrlich ascites tumor (EAT) cells in the presence of glucosone, (D-arabino- a competitive inhibitor o f hexokinase, were studied. 2) Proliferation of the cells was completely inhibited by 2 m M glucosone without severely affecting viability (dye exclusion test). N o phase specific arrest o f cell growth was observed. 3) Incorporation of [14C]thymidine into an acid insoluble fraction o f the cells decreases to 5% of the controls within 8 -1 0 h . Incorporation o f [14C]leucine begins to slow down immediately after treatment with glucosone. 4) The inhibitor (2 m M) reduces the lactate production o f the cells by 60%, respiration by about 20%; the ATP/ADP ratio slows down from 4.75 to 3.5. 5) The total inhibition o f cell proliferation by 2 m M glucosone cannot be explained exclusively by inhibition of hexokinase activity and impairment o f energy metabolism. Because o f a lack of specificity, glucosone is not a suitable inhibitor for studies on the relationship between hexo­ kinase activity and cell proliferation of tumor cells. 
  Reference    Z. Naturforsch. 36c, 255—261 (1981); received November 4/Novem ber 17 1980 
  Published    1981 
  Keywords    Ehrlich Ascites Tumor Cells, Proliferation, Energy Metabolism, Glucosone 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0255.pdf 
 Identifier    ZNC-1981-36c-0255 
 Volume    36 
4Author    Reiner Merz, Friedh SchneiderRequires cookie*
 Title    Growth Characteristics of in vitro Cultured Ehrlich Ascites Tumor Cells under Anaerobic Conditions and after Reaeration  
 Abstract    The effects of deprivation of oxygen on proliferation kinetics of in vitro grown Ehrlich ascites tumor cells were studied by means of flow cytometry. The flow cytometric results obtained by applying the BUdR-H 33 258 technique showed that 6 -8 hours after establishment of anaerobiosis cells lose their capacity for proliferation and accumulate in the late G1-phase; during this time late S cells enter the G2 compartment but do not divide while cells, which are in G2+M at the beginning of anaerobiosis divide and enter G l. Cell cycle distribution remained constant up to about 20 hours, thereafter Gl-cells enter the S-phase. Up to 24 hours of anaerobiosis cell number does not change and viability of the cells was not severely affected. Recultivation under aerobic conditions of 12 hours anaerobically treated cells revealed, that the cytokinetic properties of Gl cells were not impaired, while S-phase cells after reaeration did not enter G2 but began again to synthesize DNA forming cells with a DNA content greater than 4c. S-phase cells are most sensitive to deprivation of oxygen. 
  Reference    Z. Naturforsch. 37c, 326—334 (1982); received December 71981 
  Published    1982 
  Keywords    Ehrlich Ascites Tumor Cells, Anaerobiosis, Growth Characteristics 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0326.pdf 
 Identifier    ZNC-1982-37c-0326 
 Volume    37 
5Author    W. Erner Kroll, M. Onika Löffler, F. Rie, H. Elm, S. ChneiderRequires cookie*
 Title    Energy Parameters, Macromolecular Synthesis and Cell Cycle Progression of in vitro Grown Ehrlich Ascites Tumor Cells after Inhibition of Oxydative ATP Synthesis by Oligomycin  
 Abstract    1. In order to elucidate the significance of oxidative ATP production for the proliferation of Ehrlich ascites tum or cells, cell cycle progression, energy m etabolism and m acromolecular synthesis in the presence of oligomycin were studied. 2. In the presence of the inhibitor (20 ng/m l), lactate production and glucose uptake of the cells increased by about 30 — 35% as com pared to controls; oxygen consum ption was maximally inhibited by 30-45% and could not further be reduced by higher concentrations o f the inhibitor. ATP/ADP ratios of the oligomycin treated cells and control cells were not significantly different. 3. In the first passage in the presence o f oligomycin proliferation o f 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 accum ulate in the early S phase; division of cells which are in the S-and G 2 M com partm ent at the beginning o f oligomycin treatment accounts for the increase of cell num ber 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 num ber o f about 60% o f controls was observed within 24 h. 4. In the presence o f oligomycin incorporation of [2-14C ]thym idine is reduced to about 20% of the controls within 8 h, incorporation of [U -l4C]lysine begins to slow down im m ediately after treatment with the inhibitor, the same is true for the incorporation o f [2-14C]uridine. Transport of a-aminoisobutyric acid into the cells is not severely affected. 5. It is suggested, that not lack of energy by inhibition o f oxidative phosphorylation accounts for the arrest of cell cycle progression in the presence o f oligomycin but rather the blockade of transport of cytoplasmatic (glycolytic) ATP into m itochondria, which is caused by the high potential built up across the m itochondrial m em brane in the presence o f this inhibitor. 
  Reference    Z. Naturforsch. 38c, 604 (1983); received March 17 1983 
  Published    1983 
  Keywords    Ehrlich Ascites Tumor Cells, Oligomycin, Energy M etabolism, Cell Cycle Progression 
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 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0604.pdf 
 Identifier    ZNC-1983-38c-0604 
 Volume    38 
6Author    Requires cookie*
 Title    Growth Kinetics of the G 2-Phase of Ehrlich Ascites Tumor Cells, Separated from Anaerobically Treated Asynchronous Cultures  
 Abstract    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 
  Reference    Z. Naturforsch. 42c, 991 (1987); received August 20 1986/March 11 1987 
  Published    1987 
  Keywords    Growth Kinetics, Ehrlich Ascites Tumor Cells, Anaerobiosis, G2-Period, Over-Replication 
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 TEI-XML for    default:Reihe_C/42/ZNC-1987-42c-0991.pdf 
 Identifier    ZNC-1987-42c-0991 
 Volume    42