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Biomedical subjects

Iu V Evtodienko

Publications and source records attributed to Iu V Evtodienko.

At least 19 recordsLinked to original sources
PubMed2001

[DNA degradation and repair in human laryngeal carcinoma HEp-2 cells after combined exposure to vitamin B12b and ascorbic acid].

The formation and accumulation of DNA fragments containing no more than 23,000 pairs of bases were observed under exposure of human larynx epidermoid carcinoma cells (Hep-2) to "chemical nuclease", oxycobalamin (vitamin B12b) and ascorbic acid (vitamin C). The obtained DNA damages were repaired more slowly than those induced by gamma-irradiation in the dose adequate to the level of DNA damages. DNA reparation was not revealed after washing the cells from vitamin B12b and ascorbic acid, and in the course of cell incubation with ascorbic acid. Vitamin B12b and ascorbic acid separately did not induce degradation of DNA. DNA damages induced by "chemical nuclease" action precede the cell death observed later.

Ascorbic Acid↗
PubMed1999

[Generation of reactive forms of oxygen by polymorphonuclear leukocytes during hepatoma growth in the peritoneal cavity of animals].

In the present work, an attempt was made to analyse generation of reactive oxygen species (ROS) by polymorphonuclear leucocytes (PMN) in the course of tumour growth, using chemiluminescence (CL). A multiple increase in the capacity of polymorphonuclear leucocytes of generating active forms of oxygen in the course of tumor growth was discovered. Two causes of this process were found. 1) the increase in specific activity of leucocytes; 2) the increase in the total quantity of PMN circulating in the blood. Leucocytes were also found in the ascite liquid. PMN leucocytes were shown to participate in the antitumor defence of the organism.

Animals↗
PubMed1997

[The effect of catecholamines on the luminol-dependent chemiluminescence of rat polymorphonuclear leukocytes].

The effects of catecholamines on reactive oxygen species (ROS) generation by polymorphonuclear leucocytes were studied using chemiluminescence (CL). It has been found that catecholamines in 10(-9)-10(-10) M concentration range are able to increase reactive oxygen species generation. Within the micromolar concentration range (10(-6)-10(-5) M) cetacholamines (CA) strongly suppress CL intensity and ROS production. The efficiency of inhibitory action of CA: noradrenaline > adrenaline > dopamine > L-DOPA correspond to their redox properties. A conclusion is made that peroxidase is one of the main targets of CA effect.

Animals↗
PubMed1996

[Biological role and mechanisms of realization of the Crabtree effect in rapidly proliferating cells. The role of Ca2+ ions].

Characteristic differences in energy supply systems in normal differentiated cells versus rapidly proliferating cells including tumor cells are summarized. Previously suggested mechanisms of the Crabtree effect (inhibition of respiration by glycolysis metabolites) are specifically evaluated. The effect cannot be explained by the competition of glycolysis systems with oxidative phosphorylation for ADP and Pi. A novel mechanism of the Crabtree effect is suggested based on regulatory (inhibitory) effect of Ca2+ as the second messenger on oxidative phosphorylation in tumor cells and other rapidly proliferating cells. The Crabtree effect can be one of the main mechanisms which switch cellular energy metabolism form oxidation to anaerobic glycolysis, the latter being more beneficial for reductive biosynthetic reactions and rapid growth of the cells.

Animals↗
PubMed1995

[Redistribution of Ca2+ ions in Ehrlich ascites carcinoma cells under the action of deoxyglucose and inhibitors of the intracellular Ca2+- transporting system].

Changes in free cytoplasmic Ca2+ ([Ca2+]i) in Ehrlich ascites tumour cells were studied under the effect of deoxyglucose and agents which modify transmembrane Ca2+ fluxes. It was shown that the reason for deoxyglucose-induced [Ca2+]i increase in Ca2+ release from internal stores and the influx from the external medium. Mitochondrial metabolic inhibitors (oligomycin+KCN, oligomycin++uncouplers of oxidative phosphorylation) induce themselves some rise in [Ca2+]i and increase the deoxyglucose effect on [Ca2+]i significantly. The conclusion was made that mitochondria can participate in cytosolic Ca2+ regulation and Ca2+ redistribution in tumour cells.

Animals↗
PubMed1995

[Characteristics of reversible and irreversible Ca2+-induced efflux of Ca2+ from mitochondria in permeabilized Ehrlich ascites carcinoma cells].

The Cyclosporin A-sensitive mitochondrial permeability transition in Ehrlich ascites tumour cells has been investigated. It was shown that Ca2+ ions induce both the self-reversible and irreversible mitochondrial permeability transition. ADP effectively inhibits the reversible but has no effect on the irreversible permeability transition. Bromophenacyl bromide, a potent inhibitor of phospholipase A2, effectively inhibits both the reversible and irreversible permeability transition. Accumulation of phosphatidylcholine and phosphatidylethanolamine lysoforms in mitochondria during Ca(2+)-induced Ca2+ release from mitochondria was found. The role of lysophospholipids in the formation of the non-selective pore in inner mitochondrial membranes during the mitochondrial permeability transition was postulated.

Acetophenones↗
PubMed1992

[The effect of fluorocitrate on oxygen consumption and Ca2+ transport in the mitochondria of liver cells].

The effect of fluorocitrate on oxidative reactions and energy production systems of rat liver mitochondria has been studied. It was shown that oxidation of endogenous substrates and malate with pyruvate as well as the phosphorylation of the added ADP were inhibited by fluorocitrate. Inhibition of oxygen consumption by fluorocitrate induced the efflux of Ca2+ ions from mitochondria and a decrease in the Ca(2+)-accumulating capacity. The effect of fluorocitrate on Ca2+ transport in mitochondria is due to activation of the Ca-efflux pathway in those sensitive to ruthenium red.

Animals↗
PubMed1991

[Character and reasons for change in mitochondrial ATP content during auto-oscillation of ion currents].

The changes in the adenosine triphosphate content in the course of ionic flux oscillations in mitochondria were estimated by using the chemiluminescence method. The ATP concentration changes were shown to be of cyclic character; the oscillations in the ATP content were shifted by 180 degrees C against those of K+ fluxes. The oligomycin-induced oxidative phosphorylation blocking changed (but did not eliminate) the oscillational character of the ATP content in mitochondrial suspensions. It was concluded that substrate phosphorylation is the source of ATP under conditions of oxidative phosphorylation inhibition. Incubation of mitochondria in the presence of exogenous ATP led to suppression of ionic flux oscillations.

Adenosine Triphosphate↗
PubMed1987

[Interpretation of the phenomenon of K+ transport activation in Escherichia coli during transition to anaerobiosis].

Earlier it was demonstrated that the transition of E. coli K-12 cells to anaerobiosis is accompanied by the activation of K+ uptake. K+ that are additionally accumulated during the transition to anaerobiosis are released from the cells after the turning on of the respiratory chain. The K+ accumulation by the cells is potential-dependent both under aerobic and anaerobic conditions. A correlation was found between the degree of acidification of the cytoplasm and the rate of K+ uptake during the transition to anaerobiosis. It was assumed that under aerobic conditions the functioning of the electrogenic system of K+ uptake is concomitant with the operation of the K+ release system, K+/H+ antiporter, which is inactivated at the beginning of anaerobiosis, presumably as a result of cytoplasm acidification. This effect manifests itself as the activation of K+ uptake. The trigger function of the K+/H+ antiporter in E. coli cells was suggested to provide for the control of the intracellular pH as well as the switching from the aerobic to the anaerobic pathway of energy metabolism.

Anaerobiosis↗
PubMed1987

[Changes in cAMP levels in bacterial cells during the cell cycle].

The changes in the cAMP level during the cell cycle in the synchronous cultures of E. coli were demonstrated. Two maxima in the cAMP level were revealed during each generation period. In the cell cycle of 40-45 min duration the first increase was observed approximately in the middle of the cycle, i. e., it was coincident with the initiation of DNA synthesis. Under these conditions the cAMP level increased 8-10 times (from 0.5 to 5.0 pmole per ml of cell suspension). The second, less pronounced increase in the cAMP level was observed immediately before or during the cell division and was probably related to the regulation of the cell wall formation.

Bacteria↗
PubMed1985

[Membrane-bound Ca2+ in the mitochondria of Ehrlich ascitic tumor cells].

Ca2+ transport in mitochondria of Ehrlich ascite tumour cells and in liver mitochondria has been compared. It has been shown that in tumour cell mitochondria unlike liver ones even small amounts of Ca2+ caused marked increase in membrane-bound Ca2+ level. Therefore, a decrease in the electro-neutral Ca2+ efflux, stabilization of mitochondria membranes and inhibition of phosphorylated respiration were observed. It has been proposed that high content of membrane-bound Ca2+ is predetermined by a higher affinity of membrane phospholipids to Ca2+.

Animals↗
PubMed1982

[Permeability of the membrane of the Escherichia coli envelope for ethidium bromide].

The interaction of ethidium bromide, a fluorescent dye, with Escherichia coli cells was studied. The envelope of intact cells was shown to be impermeable for ethidium bromide molecules. The dye penetrated however into E. coli spheroplasts. The barrier properties of the cell envelope against ethidium bromide were ruptured if the cells were treated with EDTA. The results suggest that the outer membrane serves as a principal barrier against penetration of ethidium bromide inside the cells while the cytoplasmic membrane of E. coli is permeable for the dye.

Cell Membrane↗
PubMed1982

[Reversible changes in the volume of isolated mitochondria in the course of ion flux oscillations between the mitochondria and the medium].

Glutaraldehyde has been used for electron microscopic studies of mitochondrial volume fluctuation during Sr2+--induced oscillation of ion fluxes. It has been shown that the observed ultrastructural and fluctuations of mitochondria is reversible to correlate with light-scattering value as well as to the direction of ion transfer. Determination of the intramitochondrial volume at different stages of oscillatory cycle shows the increase in the volume during the process of swelling up to 2.4-5.6 times compared with the shrihkate state.

Animals↗
PubMed1982

[Description of mitochondrial K+-transport system during intensive physical work].

The content of potassium ions in rat liver mitochondria after intensive physical work (continuous swimming) is increased approximately 2-fold, while the rate of K+ efflux from the mitochondria is significantly reduced. A considerable increase of the "calcium capacity" and a decrease of the respiration rate in state 4 were found. The experimental results indicate that during intensive physical work the mitochondrial membrane resistance to the damaging effects is enhanced. A possible mechanism of these changes is discussed.

Animals↗
PubMed1982

[Kinetics of oxygen consumption, luminescence of pyridine nucleotides and the cyanine dye 3',3'-diethylthiodicarbocyanine iodide after energizing Ehrlich ascites carcinoma cells with glucose].

It has been shown that in the absence of inhibitors of oxidative phosphorylation, changes in fluorescence of 3',3'-diethylthiodicarbocyanine iodide (dis-C2-/5/) in a cell suspension of Ehrlich's ascites carcinoma reflect those in the transmembrane mitochondrial potential. Addition of glucose to the cells in the presence of respiratory inhibitors similar to rotenon induces oscillations in the membrane mitochondrial potential due to H+-ATPase that uses glycolytic ATP. The described changes in energy metabolism parameters are determined by impairment of the interplay between glycolysis and oxidative phosphorylation. The low rate of cytoplasmic NADH oxidation by tumor cell mitochondria favors the latter's accumulation by the cytoplasm and glycolysis inhibition. Pyruvate has been shown to be responsible for NADH oxidation and to remove glycolysis inhibition.

Animals↗