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Results for “Cell Membrane Permeability”

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At least 19 recordsLinked to original sources
PubMed1976

[Radiosensitive mutants of Escherichia coli with disrupted cell membrane permeability].

Membrane proteins and cell permeability of Escherichia coli B/r and different substrains of B/r containing mutations of loci uvrB, exrA, lon and suppressors of that mutations were studied. Membrane proteins were found to be modified only in E. coli B/r exrA. The content of 40 000--70 000 D polypeptides was increased and the content of 80 000--100 000 D polypeptides was decreased. Alteration of membrane proteins in E. coli B/r exrA was associated with the impaired permeability of cell membrane.

Cell Membrane Permeability↗
PubMedDate not supplied

Red blood cell membrane permeability of uremic and normal cells.

Although there is extensive evidence that uremic red cells are more fragile and less deformable than normal cells, there are essentially no data on red cell membrane permeability in uremia. We have obtained data for creatinine and uric acid permeability of red cells from normal and uremic individuals (dialysis patients on EPO). The creatinine permeability of uremic cells was significantly less than that of normal cells (p less than 0.02), while the uric acid permeability was significantly greater than that of normal cells (p less than 0.01). Experiments with uremic and normal cells suspended in phosphate buffered saline, and with normal cells suspended in uremic plasma, indicated that uremia alters both the red cell membrane and the plasma, with an unknown plasma constituent affecting the permeability.

Cell Membrane Permeability↗
PubMed1992

The effect of six sesquiterpenoid unsaturated dialdehydes on cell membrane permeability in human neuroblastoma SH-SY5Y cells.

The effect of six sesquiterpenes containing an unsaturated dialdehyde functionality, on cell membrane permeability in the human neuroblastoma cell line SH-SY5Y has been studied. The kinetics of the membrane leakage after addition of the sesquiterpenes were determined by measuring the efflux of radioactivity from cells preloaded with tritiated 2-deoxyglucose. The concentrations that gave 5% and 20% efflux of radioactivity as compared with control cells (EC5 and EC20) were determined for each compound. In spite of the structural similarities between the compounds, the effects on cell membrane permeability varied considerably. EC20 for polygodial, which is the most active compound, is 2.5 microM after 20-min incubation, but no leakage could be determined for merulidial even at concentrations as high as 4 mM. Rather, this compound seems to stabilize or fix the cell membrane and a lower efflux of radioactivity was observed as compared to the control cells. A quantitative structure-activity relationship analysis for the five active compounds showed a good correlation between the membrane leakage activity and certain chemical characteristics. Structural features strongly correlated with high activity were found to be: The geometry and the atomic charges of the unsaturated dialdehyde functionality, the dipole moment, the energy difference between the lowest unoccupied molecular orbital and the highest occupied molecular orbital and the lipophilicity.

Aldehydes↗
PubMed1992

Modulation of membrane permeability, cell proliferation and cytotoxicity of antitumor agents by external ATP in mouse tumor cells.

External ATP causes a remarkable change in the passive permeability of the plasma membrane in several types of transformed cells. When mouse melanoma cells, Clone-M3, were exposed to ATP in Tris-buffered saline, a great increase in the passive permeability was induced within several minutes. Longer exposure of Clone-M3 cells to external ATP led to a decrease in cell viability. Similar results were obtained with Ehrlich ascites cells, but none of these ATP effects were noted in untransformed cells such as NIH 3T3 cells or BALB/c mouse embryonic fibroblasts. The in vitro cytotoxic effects of antitumor agents (5-fluorouracil, adriamycin, mitomycin C and nimustine hydrochloride) against Clone-M3 cells were additively potentiated by treatment with external ATP, which also synergistically enhanced the cytotoxicity of vincristine. However, the effects of these drugs on mouse embryonic fibroblasts were not modulated by ATP. These results suggest that ATP-treatment is a useful means of enhancing a selective toxicity for tumor cells.

3T3 Cells↗
PubMed1978

Increased cell membrane permeability to Na+ and K+ induced by thyroid hormone in rat skeletal muscle.

Thyroid hormone (T3) increased Na+ dependent respiration accompanied by an increase in NaK-ATPase activity. Administration of T3 increased intracellular K+ concentration and Na/K ratio in thyroidectomized rats, and the Na+ efflux rate constant incubated in oxygenized Na+, K+-Ringers in euthyroid rats. However, the magnitude of the changes in intracellular K+ concentration was modest or invisible in comparison to the changes in QO2(t) and NaK-ATPase activity. The Na+ and K+ efflux rate constants in K+-free +ouabain Ringers were increased by T3 in both thyroidectomized and euthyroid rats. Thus, thyroid hormone stimulates not only Na pump but also the permeability of cell membrane to Na+ and K+. The both effects might contribute to the thyroid thermogenesis.

Adenosine Triphosphatases↗
PubMed1978

Changes in the lipid composition of ripening banana fruits and evidence for an associated increase in cell membrane permeability.

The content of total lipid in banana fruit pulp tissue remained constant during the climacteric rise induced by applied ethylene. The relative proportions of neutral lipid, glycolipid and phospholipid did not change. However, the fatty acid composition of the lipid did change during ripening. This change was confined largely to the phospholipid fraction, in which there was an increase in the proportion of linolenic acid and a decrease in the proportion of linoleic acid. The net result was an increase in total unsaturation of the fatty acids in the phospholipid fraction. Measurements of spin label motion in liposomes prepared from banana phospholipids showed that the motion and fluidity of bilayer lipids increased during ripening of the fruit from which the liposomes were prepared, probably as a result of increased lipid unsaturation during ripening. Since increases in membrane fluidity are accompanied by increases in the passive permeability to small molecules in a number of membrane systems, it is suggested that the increased leakage which has been previously demonstrated in ripening banana fruit tissue is due to increases in the permeability of at least some cell membranes.

Cell Membrane Permeability↗
PubMed1991

[Free radical oxidation of red blood cell membrane lipid structures as a trigger mechanism of an increase in red blood cell membrane permeability during blood coagulation in vitro].

The study of venous blood samples from 50 clinically normal subjects has shown that free radical oxidation of red blood cell membrane lipid structure induced by the blood sample contact with atmospheric oxygen serves a trigger rising the membrane permeability during blood coagulation in vitro. Activation of endogenous phospholipase A2 is a process dependent on the increase of intraerythrocytic concentration of calcium ions.

Blood Coagulation↗
PubMed1975

[Change in cell membrane permeability, and composition and properties of hexokinase during induced carcinogenesis].

The isoenzyme hexokinase (HK) spectrum from normal rat large intestinal mucosa consisted of 3 isoenzymes. In tumours of this localization induced by 1,2-dimethylhydrazine there proved to be a lack or marked decrease in the most rapid anodic isoenzyme. Only one HK isoenzyme was found in the metastases. Km (glucose) for tumour HK was 2--3 times lower than for normal intestinal HK; the HK activity was detected in the serum from the 1st month of the carcinogenic administration, and by the 5th month it was found in 80% of the tumour-bearing animals. No serum HK activity was ever found in control rats.

Adenocarcinoma↗
PubMed1978

Cell membrane ionic permeability, calcium ion, mitochondria, and carcinogenesis.

The interrelations between changes in cell membrane permeability, increase of intracellular concentration of calcium ion and alterations of the bioenergetic and genetic mechanisms of the mitochondria are formalized in a hypothesis of carcinogenesis. It seems very likely that changes in the permeability of the cell membrane induced by the carcinogen are responsible for increased intracellular accumulation of Ca2+. This phenomenon produces mitochondrial damage associated with permanent modifications of the structural and functional characteristics of the cell membranes as well as of the genetic mechanisms controlling cell division.

Biological Transport↗
PubMed1977

The influence of antibiotics WR 142 on permeability of cell membranes.

The influence of antibiotics WR 142 (fractions I and II and Wr 142 FPG) on transport across cell membranes of B. subtilis and C. albicans was studied. Antibiotics Wr 142 did not increase permeability of cell membranes as 86Rb was not exchanged by other monovalent ions in the presence of the antibiotic preparations. Temperature, ionic strength and pH had no significant influence on the action of these antibiotics on the cell membranes. Antibiotics Wr 142 do not form lipid-soluble complexes with alkali metal ions, and therefore do not transport these ions, in contrast to the ionophoric antibiotics. No effect of antibiotics Wr 142 on the stucture of the cell membrane depriving it of its selective function as an osmotic barrier was observed.

Anti-Bacterial Agents↗
PubMed1991

Study of the biological effects of theophylline on V79 cells: viability, membrane permeability, and metabolic cooperation.

The effect of theophylline, a specific inhibitor of phosphodiesterase, on gap junction-mediated intercellular communication between Chinese hamster V79 cells was examined. It was found that addition of theophylline to coculture of 6-thioguanine-resistant (TGr) and 6-thioguanine-sensitive (TGs) V79 cells significantly increased the recovery of TGr cells. This finding indicates an inhibition of metabolic cooperation of V79 cells by theophylline. Theophylline was tested at concentrations less than 0.3 mg/ml, which were neither cytotoxic (after short or continuous exposure) nor inhibited the synthesis of DNA, RNA, and proteins. At the tested concentrations, no change was found in the membrane permeability of cells. Theophylline did not increase the incorporation of glucose into the cells.

Animals↗
PubMed1990

Permeability of neutral vs. anionic dextrans in cultured brain microvascular endothelium.

The luminal surface of vascular endothelium contains glycocalyx residues that establish an overall negative charge. Recent evidence has suggested that local endothelial surface charge properties may account for the permeability properties of various macromolecules. It has also been suggested that altered membrane charge on the luminal side may play a role in thrombogenesis and atherogenesis. The relationship of macromolecule charge to endothelial cell permeability was examined in vitro using mouse brain microvessel endothelial cells grown to confluence on a nitrocellulose filter separating a double-chamber system. Endothelial permeability to 4K and 10K fluorescein-labeled neutral dextrans was compared with the permeability to 4K and 10K fluorescein-labeled anionic dextrans (sulfated). After 1 h, there was significantly greater permeability of neutral fluorescein-labeled dextran than of anionic fluorescein-labeled dextran in each particle size. In addition, there was significantly greater permeability of 4K than 10K fluorescein-labeled dextrans of either charge. The findings indicate that charge in addition to size plays an important role in the movement of macromolecules across cultured microvascular endothelial cells.

Animals↗