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Biomedical subjects

A A Vereninov

Publications and source records attributed to A A Vereninov.

At least 19 recordsLinked to original sources
PubMed2004

[Cell shrinkage during apoptosis is not obligatory. Apoptosis of U937 cells induced by staurosporine and etoposide].

A study was made of apoptotic cell shrinkage, which is generally believed to be a hallmark of apoptosis. The two conventional models of apoptosis were used for examination of changes in cell water balance--one is apoptosis caused in human lymphoma cell line U937 by staurosporine, and the other by etoposide. Intracellular water was determined by measuring buoyant density of cells in continuous Percoll gradient. Apoptosis was recognized by microscopy and flow cytometry. Apoptosis caused by staurosporine (1 microM, 4 h) was found to be associated with a decrease in cell water content by almost 24%. In contrast, no decrease in cell water content was observed in U937 cells incubated with etoposide (50 microM, 4 h), in spite of the number of features suggesting the presence of apoptosis, such as the appearance of apoptotic bodies, chromatin condensation and fragmentation and disappearance of S-phase cells in DNA histogram. It is concluded that definition of apoptosis as "shrinkage-necrosis" (Kerr, 1971) needs correcting: the distinction of apoptotic cells involves the absence of swelling, rather than cell shrinkage.

Antineoplastic Agents, Phytogenic↗
PubMed2003

[Water and ion balance in rat thymocytes under apoptosis induced with dexamethasone or etoposide. Ion-osmotic model of cell volume decrease].

Cell ion and water balance was studied with respect to analysis of the osmotic model of apoptotic volume decrease (AVD) in rat thymocytes under dexamethasone (1 microM, 4-6 h) or etoposide (50 microM, 5 h) treatment. Intracellular water content was determined by measurement of cell buoyant density in continuous Percoll gradient, while intracellular potassium and sodium contents were determined by flame emission analysis. Apoptosis was verified by an increase in cell buoyant density, fluorescence of cells stained with Acridine orange and Ethidium bromide (flow cytometry), by changes in the cell cycle and the appearance of sub-diploid peak in the DNA histogram (flow cytometry), and by a decrease in cell size examined with light microscope. A separate fraction of dense cells with reduced size was found to appear after dexamethasone or etoposide treatment. This fraction was considered as apoptotic. An increase in buoyant density of apoptotic cells corresponded to a decrease in cell water content. In apoptotic cells vs. cells with normal buoyant density, the intracellular potassium content was lower, but sodium content was higher. The sum of potassium and sodium contents was lower in apoptotic cells. Taken into account the loss of anions, associated with the loss of cations, the bulk decrease in ions content has been sufficient to be accounted for cell volume decrease on the basis of the ion-osmotic model.

Animals↗
PubMed2001

Differential transcription of ion transporters, NHE1, ATP1B1, NKCC1 in human peripheral blood lymphocytes activated to proliferation.

This work, using RT PCR, studied expression of mRNAs encoding ion transporters, the Na/H antiporter (NHE1), the beta subunit of the Na,K-ATPase pump (ATP1B1), the NaK2Cl symporter (NKCC1), and some proteins unrelated to ion transport: the serum and glucocorticoid dependent kinase (hSGK), beta-actin, a glycolytic enzyme (GAPDH), and regulators of proliferation and apoptosis (p53, Bcl-2) during activation of human lymphocytes with phytohemagglutinin for 4-24 h. Within 24 hours the mRNA levels of NHE1, beta-actin, Bcl-2, and p53 increased by more than 100%, the mRNA levels of ATP1B1, GAPDH, and hSGK, by about 50%, while the mRNA levels of NKCC1 decreased transiently. These results indicate a differential transcriptional control of NHE1, ATP1B1, and NKCC1 following a proliferative stimulus of human lymphocytes.

Carrier Proteins↗
PubMed2001

[Study of "group" expression of mRNA of the ion transporters ATP1B1, NHE1 and NKCC1, beta-actin, glycerophosphosphate dehydrogenase, proteins regulating proliferation and apoptosis of p53, Bcl-2, IL-2 and hSGK kinase at the prereplicative stage of human lymphocyte activation].

Previously, we found no segregation in F2 obtained from crosses between two Dileptus anser clones differing (under the same culture conditions) in their serotypes, i.e. in their immobilization antigens (i-antigens); indeed, all the F2 clones had mixed, i.e. hybrid serotype, being immobilized simultaneously with both immune sera developed against either parental clone (Uspenskaya, Yudin, 2000). Presently, experiments were carried out to see if this unusual phenotype would be re-expressed after a temporary switching off. To switch off both expressed i-antigens, serotype transformation was induced in the F2 clones by shifting the culture temperature from 25 to 17 degrees C. Two weeks later, when the clones returned to the initial temperature conditions, each of them was seen to re-express both parental i-antigens. This result is discussed with reference to the role of i-antigens in regulation of their own expression as has been suggested by some authors.

Actins↗
PubMed2000

The role of actin cytoskeleton in the generation of surface oscillations of red blood cell ghosts.

We have studied the effects of three compounds on surface oscillations of human red blood cell ghosts: the P-ATPase inhibitor, suramin; the fluorescent dye of a similar structure, 1,8-anilinonaphthalene sulfonate (ANS); and subfragment 1 of skeletal muscle myosin (S1). It has been found that suramin (10 microM), ANS (100 microM) and S1 (2 mg/ml) suppress the surface oscillations reversibly. The shape of the ghosts remains unchanged. We have also found that suramin and ANS inhibit the ghosts' non-transport (presumably, F-actin-associated) ATPase. The results of the present study suggest the important role of actin ATPase in the generation of cell surface oscillations. The effect of S1, the protein which increases the torsional, but not the bending, rigidity of F-actin upon binding to filaments, favours the possibility that just the torsional dynamics of actin protofilaments leads to the observed oscillations of the ghosts' surface.

Actins↗
PubMed1999

Functional expression of the Na/K pump is controlled via a cyclosporin A-sensitive signalling pathway in activated human lymphocytes.

An immunosuppressant cyclosporin A (CsA) inhibits T-cell proliferation by blocking the nuclear factor of activated T-cells (NFAT) required for expression of the interleukin-2 (IL-2) gene. This work has demonstrated for the first time that in human blood lymphocytes (HBLs) activated by phytohemagglutinin (PHA), CsA at anti-proliferative doses inhibits the late sustained increase in ouabain-sensitive Rb(K) influxes, which accompanies the growth phase of G0/G1/S transition. CsA affects neither the initial, transient activation of the pump in response to PHA nor the ouabain-resistant ion fluxes during cell cycle progression. When the HBLs were rendered competent to proliferate by phorbol 12,13-dibutyrate ester and ionomycin in the presence of CsA, the exogenous IL-2 did not bypass the initial inhibitory effect of CsA on the long-term pump enhancement. When applied after the competence induction, CsA produced no effect on the sustained increase in ouabain-sensitive Rb influxes during the IL-2-induced progression phase. These results indicate that in activated HBLs, (1) IL-2 is involved in functional expression of the Na/K pump during cell transition from quiescence to proliferation, (2) the cell cycle-associated upregulation of the pump is related to a CsA-sensitive signalling pathway.

Cyclosporine↗
PubMed1998

Na, K-ATPase pump in activated human lymphocytes: on the mechanisms of rapid and long-term increase in K influxes during the initiation of phytohemagglutinin-induced proliferation.

Functional expression of Na, K-ATPase pump as determined by ouabain-sensitive Rb influxes has been investigated in human peripheral blood lymphocytes, activated by phytohemagglutinin (PHA) from resting state to proliferation. It is found that a rapid twofold elevation of ouabain-sensitive Rb influx in response to PHA is followed by a long-term increase in pump activity, which precedes the DNA synthesis and is temporally related to the growth phase of mitogenic response. Unlike the early pump activation, the late enhanced pump activity is not the result of elevated cell Na content, it is inhibited by cycloheximide and requires new protein synthesis. Actinomycin D and alpha-amanitin, in doses, which suppress the PHA-induced increase in the RNA synthesis, do not abolish the elevated Rb influx until 20-24h of mitogenic activation and inhibit the late, growth-associated increase in Rb influx. It is concluded that (1) in mitogen-activated cells both short- and long-term control is involved in the enhanced pump activity, and (2) translational and transcriptional mechanisms may contribute to the long-term up-regulation of Na, K-ATPase pump during blast transformation of human lymphocytes.

Amanitins↗
PubMed1998

Cyclosporin A inhibits long-term activation of Na+,K+ pump in phytohemagglutinin-stimulated human lymphocytes.

The effect of the immunosuppressive drug cyclosporin A (CsA) on the K (Rb) influx, intracellular K and Na contents, and on the major parameters of lymphocyte activation have been investigated in human peripheral blood lymphocytes activated by phytohemagglutinin (PHA). CsA suppressed protein, RNA, DNA syntheses and cell proliferation by 49.8 +/- 4.3, 67.6 +/- 10.1, 60.4 +/- 5.3 and 60.0 +/- 5.1%, respectively (n = 10) within 48 h. It also inhibited the late long-term Na+,K+ pump activation, as determined from the ouabain-sensitive Rb uptake, and prevented the increase in the intracellular K content at the late stages of G0/G1/S progression. Cyclosporin A did not affect the early transient pump activation, the dynamics, of ouabain-resistant influxes and the intracellular Na content in PHA-activated lymphocytes. When added 1 h after PHA, CsA neither affected the activation of the pump-mediated Rb influxes nor the increase in the intracellular K content. It is concluded that in activated human lymphocytes, the long-term activation of Na+,K+ pump associated with the mitogen-induced blast transformation, as well as the late increase in K content depend on the T-cell growth factor interleukin-2.

Blood Proteins↗
PubMed1997

[The effect of NaK2Cl symport and chloride channel permeability on ion flux balance and on transmembrane ion distribution in different types of animal cells].

The relationships between monovalent ion fluxes via major cell membrane pathways (Na/K pump, NaK2Cl symporter, electroconductive sodium, potassium and chloride channels) and steady state transmembrane ion distribution, membrane potential and cell water content were calculated for the high potassium animal cells with high and low membrane potential. It is found that variation in NaK2Cl symport or chloride electroconductive permeability causing changes in cell water content of high magnitude do not lead to significant changes in the intracellular Na/K ratio or membrane potential, in contrast to the effects caused by variation in the Na/K pump fluxes or permeability of the Na and K channels. It is shown that water content in cells with a high membrane potential, e.g. of about 70 mV, cannot be increased due to an increase in NaK2Cl symport by more than 1.6 times. In cells with a low membrane potential an increase in symport leads to a decrease in water content, which is also limited. In cells with membrane potential of about 10 mV the water content cannot be decreased more than by 1.8 times. When NaK2Cl symporter is operating, the effect of chloride channel permeability on the ion and water balance is quite opposite to the symport and is limited by the same boundaries. It is shown that effects caused by changes in symport and in chloride permeability can be differentiated only by the analysis of kinetic (fluxes, transport rate constants etc.) but not "static" characteristics of ion distribution. It is shown that under some circumstances the influence of NaK2Cl symport and chloride channel permeability on ion and water balance can be strong even at a very small symport share in the overall flux.

Animals↗
PubMed1995

Long-term enhancement of Na,K-ATPase pump during blasttransformation of human lymphocytes is controlled first by translational, then by transcriptional mechanisms.

The transition of phytohemagglutinin-activated human lymphocytes from resting state to proliferation is accompanied by a long-term increase in ouabain-sensitive Rb(K) influx which is closely related to a cyclosporin A-sensitive step of G0/G1/S progression. At least two distinct phases of the up-regulation of cation pump has been revealed: the initial stage (5-20 h) which is cycloheximide-inhibitable and actinomycin D (alpha-amanitin)-unaffected, and the later stage (after 20 h) which is cycloheximide- and actinomycin D (alpha-amanitin)-inhibitable. Thus, the enhanced Na,K-ATPase pump during the cell progression from quiescence to proliferation is controlled both at translational and transcriptional levels.

Cell Cycle↗
PubMed1995

[The role of ionic transporters in the long-term regulation of the water content in animal cells. The mathematical model and real lymphoid cells].

Ion and water balance as well as flux balance in the animal cell, equilibrated to anisosmotic solutions, are computed for a cell model supplied by Na,K-ATPase pump, electroconductive ion channels and symporters Na-Cl, K-Cl and NaK2Cl. It is shown how the potency of each of the principal transporters to regulate cell volume depends on such conditions as the state of other ion transporters and channels, initial ion distribution and membrane potential. The obtained data are applied to studying changes in cation and water balance in the Jurkat lymphoid cells equilibrated to hyposmotic solutions. It is concluded that a steady state volume regulation in Jurkat cells, maintained in hyposmotic media 180 mosM for up to 24 h, is achieved due mainly to non-ionic mechanisms. Under the lower osmolarity of the media, 155 mosM, the ionic cell volume regulation occurs. The increase in PCl and/or the decrease in Na-Cl symport (or its equivalent, e.g. Na/H and Cl/HCO3 exchange) are considered as the most probable cause of the long-term volume decrease in lymphoid cells.

Animals↗
PubMed1993

Expression of mRNAs encoding the alpha 1 and the beta 1 subunits of Na+, K(+)-ATPase in human lymphocytes activated with phytohaemagglutinine.

Increase in Na+, K(+)-ATPase mRNAs was detected in activated lymphocytes by the RT-PCR method. alpha 1 subunit mRNA gradually increased with time and by 36 h was 2.4 times higher than at the start. Increase in the beta 1 mRNA was transient reaching a maximum in the 8 h probe and declining to the initial level in the 24 and 36 h probes. The elevation of Na+, K(+)-ATPase mRNAs does not underlie a cycloheximide-inhibited increase in cation pumping peculiar to the prereplicative period as can be judged from the fact that Act D fails to eliminate PHA-induced enhancement of pump fluxes.

Cells, Cultured↗
PubMed1991

[Ionic, electrical and water balance in the animal cell. The system with active cation transport, Goldman's channels and the Na + K +2Cl-type symport].

The relations between intracellular potassium, sodium water content and resting potential on the one hand and the ion transport parameters and intracellular electrical charge on the other hand were computed for a model of animal cell with a several ion transporters and variable intracellular charge. The case of the balanced ion distribution is considered. The results are presented in a graphical form.

Animals↗
PubMed1991

[The transport and distribution of monovalent cations during the blast transformation of human peripheral blood lymphocytes activated by phytohemagglutinin].

Potassium (rubidium) influx, sodium and potassium contents, as well as size distribution, DNA and protein contents and synthesis have been examined in PHA-activated human lymphocytes within 0.5-72 h. A complex set of ionic events was found to include at least two stages of the increase in potassium and sodium contents per g cell protein and in ouabain-sensitive potassium influx which are preceded by a decrease in potassium content by almost 17% within the first 2-5 h. The kinetics of potassium and sodium changes has own pattern for each of cations, thus indicating definite changes in the ouabain-resistant transport of potassium and sodium during the G0----G1----S progression. The late increase in potassium content per g cell protein was found to correlate with the growth in cell size. This finding confirms the rule which was stated earlier for other animal cells, i. e. cells that prepare to proliferate are to raise their potassium per g cell protein up to the level of 0.8-1.0 mmole (Vereninov. Marakhova, 1986).

Biological Transport↗
PubMed1985

[Dependence of ion transport across the plasma membrane on the density of the cell culture. I. Ion flows and the potassium and sodium content in 3 Chinese hamster cell lines (CHO)].

Cation transport has been investigated in three lines of Chinese ovary cells CHO-K1 during the cell culture growth. With the increase in the cell density potassium and sodium contents decreased from 1.2 to 0.8-0.5 and from 0.5 to 0.15-0.1 mmole/g protein, respectively. The time courses of potassium and sodium changes were different, and the increase in intracellular K/Na ratio from 1.5-2.0 to 5-10 with the increase in cell density was revealed. The rubidium influx was found to decrease during the culture growth mainly due to the decrease in ouabain-inhibitable and (ouabain + furosemide)- non-inhibitable influxes. The changes in cation fluxes and cation contents were observed in transformed cells without contact inhibition of division and were considered as a manifestation of density-dependent alterations of plasma membrane.

Animals↗
PubMed1985

[Heavy water inhibition of the transport of alkaline cations across the muscle membrane. I. A comparison of different types of sodium transfer].

The sodium efflux from the frog sartorius muscle into the media of different ion composition, prepared with ordinary and heavy water, was measured by radiotracer and flame-emission techniques. About the half of the sodium in muscles was substituted for lithium. The ouabain-sensitive, as well as external potassium- and external sodium-dependent components of the efflux were found to be totally inhibited in D2O, whereas the residual efflux observed in sodium- and potassium-free magnesium medium was diminished in D2O only by one half. A conclusion is made that the decrease in sodium efflux in D2O is due to the inhibition of sodium transfer through the Na, K-ATPase transport system.

Animals↗
PubMed1985

[Heavy water inhibition of alkali cation transport across the muscle membrane. II. A comparison of the action of D20 and ouabain on the sodium efflux and rubidium influx in magnesium media].

The action of heavy water and ouabain on sodium effluxes and rubidium influxes has been measured and compared in frog muscles (m. sartorius, R. temporaria). Approximately half of muscle sodium was substituted by lithium by preliminary incubation in mixed sodium-lithium media. The ratio of the ouabain-sensitive parts of rubidium influx and sodium efflux is 7.3:10.5, and that of D2O-sensitive parts of corresponding parameters is 7.5:11.3. A conclusion is made that D2O-effect on the Na, K-ATPase system of muscles under investigation resembles ouabain-effect on sodium effluxes as well as on rubidium influxes.

Animals↗