Showing papers in "Ukraïns'kyĭ biokhimichnyĭ zhurnal in 2005"

6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase gene family overexpression in human lung tumor.

Abstract: The 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFKFB) is a family of bifunctional enzymes which is responsible for maintaining the cellular levels of fructose-2,6-bisphosphate, a powerful allosteric activator of glycolysis. Here we report the overexpression of PFKFB-1, -2, -3 and -4 mRNA in the human lung cancers when compared with corresponding normal tissues counterparts as well as PFKFB-4 and -3 protein levels. The lung carcinoma cell line A549, under conditions of normal oxygen tension, has also shown increased transcript levels of PFKFB-2, -3 and -4 when compared to normal tissues. Moreover, hypoxia highly induced the expression of PFKFB-2, PFKFB-3 and especially PFKFB-4 isozymes are highly induced in the lung carcinoma cells. Thus, our results' clearly demonstrated overexpression of PFKFB gene family isozymes in the lung cancers and they possible role in the Warburg effect.

The reduction of Alamar Blue by peripheral blood lymphocytes and isolated mitochondria.

Abstract: Alamar Blue is a widely used nontoxic indicator of cell proliferative activity, which penetrates quickly through the biological membranes and can be easily reduced by intracellular enzymes. Accumulation of reduced fluorescent form of Alamar Blue during short-term culture of human peripheral blood lymphocytes may be used as a cell viability test since it was prevented by disruption of plasma membrane by digitonin. The inhibition of Alamar Blue reduction by NaN3 indicates that its metabolism is associated with mitochondrial activity. A compaative study of Alamar Blue reduction and oxygen consumption on isolated rat liver mitochondria shows, that the Alamar Blue reduction is not associated with the activity of specific complex of respiratory chain and it seems to be an integral indicator of oxidation-reduction activity of respiratory chain components.

Incorporation of labelled N-acylethanolamine (NAE) into rat brain regions in vivo and adaptive properties of saturated NAE under x-ray irradiation.

Abstract: Regional distribution of exogenous N-palmitoylethanolamine in the rat brain was investigated in the study. Possible protective and adaptive effect of N-stearoylethanolamine under 2 Gy whole-body X-irradiation and changes of brain lipid composition were also studied. It was found that after per os administration to rats N-([9,10-3H]-palmitoyl)-ethanolamine was primarily accumulated in hypothalamus, pituitary and adrenal glands and the label amount in brain was 0.95% of the oral dose. Quantities of palmitic acid in total brain phospholipids and plasmalogen form of phosphatidylcholine were increased; free cholesterol and diacyl form of phosphatidylcholine were decreased in 2 weeks after irradiation. 11-OH-corticosteroid level in the blood of exposed rats was decreased in comparison with control animals. N-stearoylethanolamine pre-treatment prevented from increasing the plasmalogen form of phosphatidylcholine and decreasing its diacyl form and restored 11-OH-corticosteroid level in the blood of irradiated rats. Recovering of brain free cholesterol level was observed when N-stearoylethanolamine was post-treated. So, the accumulation of N-([9,10-3H]-palmitoyl)ethanolamine in brain indicates its penetration through blood-brain barrier and suggests the possible role of saturated N-acylethanolamines in brain functioning, particularly, in stress response regulation of the organism by hypothalamus-pituitary-adrenal system. N-stearoylethanolamine treatment of irradiated rats causes protective effect concerning the of irradiation induced changes in the brain lipid composition and in 11-OH-corticosteroid level and modifies phospholipid fatty acid composition.

Effect of some isoquinoline alkaloids on enzymatic activity of acetylcholinesterase and monoamine oxidase

Abstract: It has been shown, that some benzo[c]-phenanthridine and diisoquinoline alkaloids isolated from Chelidonium majus L and Macleaya (Bocconia) cordata and M microcarpa (berberine, sanguinarine, chelidonine) and of drugs ("Ukrain" and "Sanguirythrine") inhibited the enzyme activity of acetylcholinesterase from human erythrocyte and monoamine oxidase from the rat liver All agents under study have been shown to be reversible inhibitors of the enzymatic hydrolysis of acetylthiocholine It has been determined that chelidonine belonged to reversible inhibitors of a competitive type, all other examined agents have been demonstrated to be inhibitors of a mixed competitive-noncompetitive type, and a greater contribution to the inhibition was made by the competitive constituent Among all examined agents berberine, sanguinarine and "Sanguirythrine" were the strongest inhibitors of this reaction and chelidonine and "Ukrain" were much weaker All agents under study have been shown to be irreversible inhibitors of the oxidative deamination reaction of serotonine and tyramine and not to influence the oxidative deamination reaction of benzylamine as a substrate Among the examined agents, alkaloid sanguinarine and drug "Ukrain" are the strongest inhibitors of the reaction, alkaloids berberine, sanguinarine and "Sanguirythrine" exhibit a weaker action

Age-related effects of methionine-enriched diet on plasma homocysteine concentration and methylation of hepatic DNA in rats.

Abstract: In the present study we determined the age-related effect of methionine-enriched diet, a model of hyperhomocysteinemia, on the level of plasma homocysteine and hepatic global DNA methylation in rats. Feeding methionine diet to middle-aged rats for only 14 days resulted in a significant increase in plasma homocysteine level and DNA hypomethylation. In contrast, feeding the methionine-containing diet for 2 weeks to juvenile or post-pubertal animals did not alter the level of plasma homocysteine or hepatic DNA methylation. Supplementation of the methionine-enriched diet with vitamins B6, B12 and folic acid prevented both hepatic DNA hypomethylation and an increase of plasma homocysteine concentration in the middle-aged rats. These findings indicate that the elevated level of plasma homocysteine may be indicative of much broader and deeper alterations in intracellular methylation dysfunction, and suggest that dietary enrichment with B-vitamins is essential for the metabolism of homocysteine, especially in adult animals.

[Comparative study of properties of Na+, K+-ATPase and Mg2+-ATPase of the myometrium plasma membrane].

Abstract: The comparative research of catalytic properties of two ATP-hydrolases of the sarcolemma of the smooth muscle of the uterus--ouabaine-sensitive Na+,K+-ATPase and ouabaine-resistent Mg2+-ATPase is carried out. The specific enzymatic activity of Na+,K+-ATPase and Mg2+-ATPase makes 10.2 +/- 0.7 and 18.1 +/- 1.2 mmol P/mg of protein for 1 hour, accordingly. The action of ouabaine on Na+,K+-ATPase is characterized by magnitude of quotient of inhibition I0.5=21.3 +/- 1.5 mkM. Processing of the sarcolemma fraction by digitonin in concentrations 0.001 +/- 0.1% promotes an activation of Na+,K+ATPase and Mg2+- ATPase, and in the first case much more efficiently than in the second. The kinetics of accumulation of the product of ATP-hydrolase reactions of phosphate satisfies the laws of the zero order reaction (incubation time--about 10 min). Na+,K+-ATPase is highly specific concerning the univalent cations--Na+, K+, however Li+ can partially substitute K+. Activity of Mg2+-ATPase is not specific concerning univalent cations. The dependence of Na+,K+-ATPase activity on pH in the range of 6.0-8.0 is characterized by the bell-shaped curve, at the same time the linear dependence on pH is peculiar to Mg2+-ATPase. The functioning of Na+,K+-ATPase is provided only by ATP, in the case of Mg2+-ATPase ATP can be successfully replaced with other nucleotidetriphosphates. It is supposed that the obtained experimental data can be beneficial in further research of membranous mechanisms underlying the cation exchange in the smooth muscles, in particular when studying the role of the plasma membrane in the maintenance of electromechanical coupling in them, and also in the regulation of ionic homeostasis in myocytes.

Novel and simple ELISA-based method for antibody affinity determination.

Abstract: New coordinates for antibody affinity determination by ELISA are suggested. The suggested approach is very simple but at the same time it is more convenient and is deprived of the drawbacks inhered in the earlier suggested methods. The examples of antibody affinity determination by the suggested methods for both simulative and experimental binding curves are considered. It was demonstrated that the suggested methods allow getting more precise values of antibody affinity.

Pharmacokinetics of the doxorubicin magnetic nanoconjugate in mice. Effects of the nonuniform stationary magnetic field

Abstract: Pharmacokinetics of the doxorubicin (DOX) conjugates with magnetite nanoparticles of the core/ shell type in mice following i.v. injection in a dose of 12.5 microg Fe/g tissue w/w was studied using electron spin resonance technique (ESR). Conjugation of the DOX with magnetic nanoparticles was shown to considerably decrease DOX bioavailability in the heart and kidney tissues compared to the free DOX. A non-uniform stationary magnetic field B of 210 mT and [deltaB] of 200 mT/cm was found to be efficient in increasing DOX conjugate bioavailability in the target site. The magnetic field was also found to inhibit conjugate accumulation in the liver resulted in the increased bioavailability of the conjugates in the blood. The phenomenon can be associated with in vivo inhibition of the phagocytic activity of the immunocompetent cells upon application of magnetic fields. Morphometry data in agreement with pharmacokinetic data revealed a decrease in the conjugate concentration in the liver tissue and cells as well as the relative decrease in conjugate concentration in the Kupffer cells compared to hepatocytes upon application of magnetic fields.

Molecularly imprinted polymers--tyrosinase mimics.

Abstract: Synthetic polymers mimicking the enzyme tyrosinase have been prepared by the molecular imprinting of a complex between Cu (II) and catechol and ethyl ester of urocanic acid in an ethylene glycol dimethacrylate copolymer. Optimised polymer systems demonstrated catalysis, Michaelis-Menten kinetics and competitive inhibition similar to those of mushroom tyrosinase. The polymers benefited from superior chemical and mechanical stability in comparison with natural enzyme.

[Vitamine-like substances L-carnitine and acetyl-L-carnitine: from biochemical studies to medicine].

Abstract: Recently reported data clarify our understanding of the molecular aspects of carnitine in medicine. Carnitine is a compound necessary for the transport of acyl-CoA across the inner mitochondrial membrane for their beta-oxidation. Only L-isomer of carnitine is biologically active. The D-isomer may actually compete with L-carnitine for absorption and transport, increasing the risk of carnitine deficiency. By interaction with CoA, carnitine is involved in the intermediary metabolism by modulating free CoA pools in the cell. Detoxification properties and anabolic, antiapoptotic and neuroprotective roles of carnitine is presented. Carnitine deficiency occurs as a primary genetic defect of carnitine transport and secondary to a variety of genetic and acquired disorders. The pathophysiological states associated with carnitine deficiency have been summarized. L-Carnitine is effective for the treatment of primary and secondary carnitine deficiencies. Acetyl-L-carnitine improves cognition in the brain, significantly reversed age-associated decline in mitochondrial membrane potential and improved ambulatory activity. The therapeutic effects of carnitine and acetylcarnitine are discussed.

Kinetic analysis of the influence of inverse effectors (inhibitors and activators) on enzymatic (transport) activity of proteins

Abstract: The method is proposed for calculation of the most important parameters of the two-stage enzymatic or transport process--modification factors alpha and beta (which characterize the effector action mechanism) as well as the inhibition constant K(i) or activation constant K(a) (characterize the effector affinity for protein). The method was derived as based on the analysis of kinetic regularities of the action of reversible effectors (inhibitors and activators) on the catalytic (transport) activity of proteins. The method is based on the titration of enzymatic (transport) protein by the substrate with the absence and with presence of the effector taken in one of concentrations as well as determination (under the fixed substrate concentration) of the inhibition coefficient i(0.5) (in case of the inhibitor action) or the activation coefficient a(0.5) (in case of the activator action). Practical use of the method has been demonstrated on the example of reversible inhibition to eosine Y (2', 4', 5', 7' - tetrabromofluorescein) ofthe reaction of enzymatic hydrolysis of ATP catalyzed by highly purified transport Ca2+, Mg(2+)-ATPase isolated from the smooth-muscle sarcolemma. In this case the inhibitory effect is characterized by the following parameters: alpha = 6-8 > 1; beta = 0.50-0.53 < 1; inhibition constant K(i) = 10(-9) - 10(-8) M. Consequently, judging from the values of alpha and beta, the eosine Y effect on the analyzed Ca2+, Mg(2+)-dependent ATP-hydrolase enzymatic reaction is based on the mechanism of the mixed inhibition (one can observe the inhibition of the both stages of enzymatic transformation--the substrate binding with the enzyme and decomposition of "Michaelis complex" in the direction of formation of the reaction products). The inhibitor itself, in correspondence with K(ij) values is characterized by rather high affinity for Ca2+, Mg(2+)-ATPase. It is supposed that the proposed approach can be useful when identifying the type of the reversible effector action on the enzymatic (transport) activity of proteins, estimation of real affinity of the inhibitors and activators for the latter.

[The role of fibrin clot degradation products in the regulation of vital functions of PC-12 cells].

Abstract: The products of the fibrin clot hydrolysis performed by PC-12 cells modulated dose-dependently the rate of cell proliferation and favored their survival when seeded in suboptimal density. Co-incubation of PC-12 cells with fibrin degradation products enhanced cell adhesion to tissue culture plastic, as well as the number of nicotinic acetylcholine receptor alpha3 and alpha5 subunits expressed. It was demonstrated that, in fact, such a heterogeneous and comprehensive influence was a sum of effects exerted by different fibrin fragments. Low molecular weight fraction (below 30 kDa), but not a purified alphaC-domain, stimulated PC-12 cell proliferation, diminished their adhesion to plastic, increased nicotinic receptor expression and caused processes outgrowth. On the contrary, high molecular weight products, in particular D, DD and E fragments, enhanced PC-12 adhesion to plastic and, as a result, slowed cell division. Both high and low molecular weight fragments favored the survival of PC-12 cells. These results showed that fibrin degradation products support the vital functions of neuron-like cells, favor their contacts with extracellular surrounding and act as neurotrophic factors.

[Comet assay of DNA fragmentation: modification of silver staining for obtaining permanent preparations].

Abstract: Modification of comet analysis is proposed for obtaining permanent preparations by DNA staining with silver compounds. The sensitivity of staining is similar to that observed at the treatment by ethidium bromide and other fluorochromes. The advantages of the method are stability of slides and possibility of their reinvestigation by light microscopy. The method does not need expensive fluorescent microscope and lacks contacting with carcinogenic compounds and UV light irradiation.

[Lysalbinic acid--a new absorption enhancer for the buccal delivery of peptide drugs].

Abstract: The delivery of peptide drugs via the buccal mucosa is more convenient and safe approach than most other delivery methods. However, the efficiency of the buccal system of protein delivery is not yet able to compete with injection method. To improve its efficacy a new generation of absorption promoters that would be sufficiently enchance penetration and at the same time cause no irritation or unpleasant taste should be developed. Lysalbinic acid, a product of the alkaline hydrolysis of egg albumin, meets those requirements. The paper describes production and general physico-chemical properties of the lysalbinic acid. Lysalbinic acid has been shown to increase permeability of the oral mucosa for some peptide compounds. It is recommended to use lysalbinic acid as an absorption enhancer for the development of novel buccal peptide drugs.

[Relese of Ca2+ from mitochondria after mitochondrial membrane depolarisation].

Abstract: With the aid of specific inhibitors of Ca(2+)-uniporter (ruthenium red) and mitochondrial permeability transition pore, PTP (cyclosporine A) it is shown that PTP opening takes place after loading the rat liver mitochondria with calcium and depolarisation of mitochondrial membrane with protonophore (carbonyl cyanide m-chlorophenyl hydrazone, CCCP), and the pore opening accounts for accelerated efflux of calcium from mitochondrial matrix as well as availability of "rapid" component of two-exponential kinetic curve of Ca(2+)-efflux. An analysis of kinetic data of Ca2+ transport after membrane depolarisation also confirms our earlier observations that time frame of the pore open state is restricted, and membrane integrity is restored before all the calcium load is delivered into incubation medium. The absence of additivity between the shares of Ca(2+)-uniporter and PTP in Ca(2+)-transport is observed, and conclusion is made that partial share of PTP in calcium transport is not a constant, but a variable constituent which is diminished to zero as soon as the Ca(2+)-uniporter activity reaches its maximum after the abolition of membrane potential with CCCP. Based on some observations, it is supposed also that PTP inactivation takes place during calcium translocation across the mitochondrial membrane, which could account for limited release of Ca2+ from mitochondrial matrix through the pore itself as well as relatively narrow limits of the pore open state in comparison with time scale of complete cation release from depolarised mitochondria.

Characteristics of gene expression in morphologically abnormal needles of Scots pine

Abstract: Expression of 373 genes in Scots pine morphologically abnormal needles has been analyzed with microarray analysis. It was found microarray technique allows detecting the minor changes in gene expression. The results obtained showed that changes in expression of 42 genes occur during the process of abnormal morphogenesis in the Pinus sylvestris needles. The increasing of expression level of genes encoding ubiquitin-conjugating enzyme and L-ascorbate peroxidase was revealed for all samples analyzed.

Comparative study of p53 expression in human carcinoma cell lines A549 and MCF7 under anticancer drug treatment.

Abstract: The effect of anticancer drugs on the expression of p53 protein in tumor cells was studied using the Western Blot analysis. Human lung carcinoma cell line A549 and human breast carcinoma cell line MCF7 sensitive (WT) and resistant (DOX/R) to doxorubicin were used. An increase in p53 protein expression was found in A549 and MCF7 (WT) cells treated with cisplatin, methotrexate, and doxorubicin, whereas the level of p53 was not statistically significantly changed in the MCF7 DOX/R cells. In the untreated MCF7 DOX/R cells the level of p53 protein was markedly higher than in the untreated WT MCF7 cells. A potential role of p53 protein in the development of doxorubicin-resistance in carcinoma cells is discussed.

Survival and antioxidant defence of the yeast Saccharomyces cerevisiae during starvation and oxidative stress

Abstract: The role of catalase in response of the yeast Saccharomyces cerevisiae to oxidative stress induced by hydrogen peroxide under starvation was investigated. It was shown that under conditions used in this study 0.5 mM H2O2 did not change the number of viable cells in the wild strain YPH250, but this parameter was decreased by 15% in the acatalsaemic strain YWT1. Cells treatment with 0.5 mM H2O2 for 30 min did not modify the levels of carbonyl proteins in the parental strain, but caused its 1.4-fold increase in the defective strain. The observed 1.5-fold activation of catalase in the wild strain cells in response to H2O2-stress suggests that under starvation conditions catalase can be involved in the yeast cell protection, particularly they can prevent oxidative modification of some antioxidant and associated enzymes.

[Effect of nitric oxide donors on Ca2+-uptake in the rat heart and liver mitochondria].

Abstract: The influence of NO donors, nitroglycerin (NG) and sodium nitroprusside (SNP), on Ca2+- uptake in rat heart and liver mitochondria is studied. It is shown that in vivo NG causes a rapid dose-dependent increase of Ca2+-uptake in rat heart mitochondria most pronounced at 0,5-1,0 mg/kg weight NG. This sharp increase of Ca2+-uptake is not accounted for by changes in membrane potential of mitochondria (deltapsim) because deltapsim is not influenced by less than 1,0 mg/kg NG, and moreover, decrease by approximately 30% is observed at 1,0-1,5 mg/kg NG. In vitro, on the contrary, a concentration-dependent decrease in Ca2+-uptake caused by NG as well as SNP is observed together with simultaneous decrease of deltapsim and concentration-dependent release of Ca2+ from mitochondria via Ca2+-uniporter as the result of partial depolarisation of mitochondrial inner membrane. The data obtained give an evidence that increase in Ca2+-uptake caused by NO donor in vivo takes place independently of changes in deltapsim and also is not resulted from a direct action of NO on Ca2+-uniporter. These observations allow us to suppose that activation of mitochondrial Ca2+-uptake in vivo and corresponding decrease in cytosolic Ca2+ concentration could be involved in vasodilatory action of nitric oxide.

Complexation of cyanidin with cadmium ions in solution

Abstract: The effect of complexation between cyanidin (extracted from maize seedling roots) and cadmium ions was established in solution on the basis of absorption spectroscopy and colorimetry data. Spectral parameters for identification of the pigment added to the metal has been established.

[Free radical inactivation of glucose-6-phosphate dehydrogenase in Saccharomyces cerevisiae in vitro].

Abstract: Partial purification and in vitro inactivation of glucose-6-phosphate dehydrogenase from the yeast Saccharomyces cerevisiae in the Fe2+/H2O2 oxidation system were conducted. At the protein concentration 1.5 mg/ml, the enzyme lost 50% of activity within 5 minutes of incubation in presence of 2 mM hydrogen peroxide and 3 mM ferrous sulphate. The inactivation extent depended on time and concentrations of FeSO4 and H2O2. EDTA, ADP and ATP at concentration 0.5 mM enhanced inactivation. At the same time, the presence of 0.5 mM NADPH, 1 mM glucose-6-phosphate, 10 mM mannitol, 30 mM dimethylsulphoxide or 20 mM urea diminished this process. In comparison with native enzyme, index S(0,5) of the partially inactivated enzyme for glucose-6-phosphate was 2.1-fold higher, but for NADP it was 1,6-fold lower. Maximal activity of the partially inactivated enzyme was 3-5-fold lower than that of native one.

The concentration-specific response of metallothioneins in copper-loading freshwater bivalve Anodonta cygnea.

Abstract: Metallothioneins (MTs) from digestive gland of freshwater bivalve mollusc Anodonta cygnea, exposed to 10 or to 200 microg x l(-1) copper ions during 14 days, were resolved using subsequent gel-permeation and ion-exchange chromatography on MT-1 and MT-2. In both groups of treated molluscs the content of copper in MT-2 was elevated twice. The significant elevation of this isoform, which is minor in control animals, and the increasing of the zinc level in it were also observed after treatment with 10 microg copper x l(-1). It was accompanied with Cu,Zn-superoxide dismutase (SOD) activation. Under the treatment with the 200 microg copper x l(-1) the zinc in MT-2 was at the control level, the inhibition of Cu,Zn-SOD but activation of Mn-SOD was revealed. The properties of MT-1 in all cases were similar.

[Production and characterization of the single chain antibodies against human alpha2b-interferon].

Abstract: A combinatorial library of single-chain antibodies (ScFv) from mice immunized with human alpha2b interferon (hIFN-alpha2b) was constructed. For obtaining of phage display antibodies the DNA fragments of ScFv were cloned into phagemid vector pCANTAB-5E and rescued from Escherichia coli cells by infection with bacteriophage M13. Bacterial clones synthesizing specific ScFv against hIFN-alpha2b were isolated by several rounds of affinity selection of phage library. After isolation and affinity purification of ScFv-IFN from bacteria cells a high ability to binding of the hIFN-alpha2b has been shown. The sequencing of isolated ScFv DNA and analysis of the data obtained have been carried out. The data of expression stability of obtained E. coli producers such as some features of ScFv expression are also discussed.

Amperometric biosensor for ethanol analysis in wines and grape must during wine fermentation

Abstract: The amperometric biosensor for ethanol determination based on alcohol oxidase immobilised by the method of electrochemical polymerization has been developed. The industrial screen-printed platinum electrodes were used as transducers for creation of amperometric alcohol biosensor. Optimal conditions for electrochemical deposition of an active membrane with alcohol oxidase has been determined. Biosensors are characterised by good reproducibility and operational stability with minimal detection limit of ethanol 8 x 10(-5) M. The good correlation of results for ethanol detection in wine and during wine fermentation by using the developed amperometric biosensor with the data obtained by the standard methods was shown (r = 0.995).

Effect of exogenous specific lectin on lectin activity in the wheat seedlings and leaves

Abstract: The effect of presowing treatment of wheat seeds by exogenous wheat lectin on endogenous activity of lectin as well as on RNA content in vegetative organs of wheat was investigated. The variability of lectin activity in the seedling and leaves of wheat plants was obtained. Both endogenous activity of lectin and RNA amount increase under the effect of exogenous lectin. This effect was partially inhibited by the hapten of the wheat lectin. The possibility of induction of modifications in both endogenous lectin pool and functional activity of plant genome by exogenous lectin is under discussion.

Effect of intermittent hypoxic hypoxia on energy supply of rat skeletal muscle during adaptation to physical load

Abstract: The experiment, on Wistar male rats was carried out to investigate influence of endurance training (swimming with load 7.0 +/- 1.3% body weight, 30 min a day, during 4 weeks) and additional intermittent hypoxic training (12% O2 in N2 - 15 min, 21% O2 - 15 min, 5 sessions a day, during the first 2 weeks) on the following parameters: ADF-stimulated mitochondrial respiration, lactate/pyruvate ratio, succinate dehydrogenase activity, and lipid peroxidation in skeletal muscle. The next oxidation substrates were used: 1 mmol/l succinate and 1 mmol/l alpha-ketoglutarate as well as the next inhibitor succinate dehydrogenase 2 mmol/l malonate. It was shown that physical work combined with intermittent hypoxic training led to the increase of mitochondrial respiration effectiveness in muscle energy supply under alpha-ketoglutarate oxidation in comparison with succinate oxidation as well as to the decrease of succinate dehydrogenase activity and lipid peroxidation. The study suggested that these changes may correct mitochondrial dysfunction under intensive muscular work.

[Kinetic interpretation of the original pH-dependence of enzymatic activity of "basal" Mg(2+)-ATPase of the smooth muscle sarcolemma].

Abstract: It was demonstrated in experiments made on a fraction of plasma membranes of the uterine smooth muscle cells that PH-dependence of enzymatic activity of the "basal" (Ca(2+)-independent) Mg(2+)-ATPase obtained under the conditions of determining the initial velocity of ATP hydrolysate is not bell-shaped but is characterized by linearity in the range of the values of hydrogen index 6.0-8.0. A kinetic model of Mg(2+)-dependent enzymatic hydrolysis of ATP has been suggested and analyzed; the model explains the linearity of the above pH-dependence. Results of kinetic analysis prove that the cause of linear pH-dependence of enzymatic activity of the "basal" Mg(2+)-ATPase is that the proton H+ is a competitive inhibitor of the given enzyme: the increase of protons concentration leads to a decrease of the affinity of Mg(2+)-ATP substrate for the enzyme, but it has no effect on the number of circulations of the latter. Thus the work gives a kinetic substantiation of the possible regulatory role of protons H+ as the factor of original negative inverse relation which controls the enzymatic activity of the basal Mg(2+)-ATPase "producing" protons in the myometrium cells; the concentration of protons in the near-membrane regions of the myoplasma being increased the ATPase activity decreases, and the former being decreased the latter increases. It is not excluded that owing to its original linear pH-dependence the studied ATP-hydrolase system serves as an important element of the control of proton homeostasis in the smooth-muscle cells.

[Neuroprotective effect of N-acylethanolamines in chronic morphine dependence. III. Influence on the content of neurotransmitters in the rat brain].

Abstract: The effect of the mixture of saturated and unsaturated N-acylethanolamines (NAEs) on the functional activity of catecholamine- and serotoninergic systems of the rat brain with experimental morphine dependence was investigated. A significant decrease of dopamine levels was found in the hypothalamus, midbrain and cortex of rats with morphine dependence. The administration of NAEs to rats with morphine dependence in time course dose of 35 mg/kg markedly increased the levels of dopamine in the hypothalamus, middle brain and cortex. Simultaneously the significant decrease of serotonine content was observed in the midbrain and cortex. The results obtained suggest that one of the important aspects of neuroprotective action of NAEs under morphine dependence is the restoration of dopamine content in the brain.

[Sodium azide as indirect nitric oxide donor: researches on the rat aorta isolated segments].

Abstract: A comparative investigations of heme-containing enzymes inhibitors NaN3 and NaCN effects on the rat aorta isolated segments tone has shown that NaN3 in the range of very low concentrations from 10(-9) to 10(-6) M displays pharmacological activity characteristic of nitric oxide (NO) donors, which is inhibited by NaCN. The value of vasodilatation, caused by NaN3, was also decreased in the presence of soluble guanylate cyclase inhibitor ODQ (10(-5) M). It was found that H2O2 injection to physiological solution containing NaN3 and horseradish peroxidase or catalase lead to NO2- accumulation in it, which was blocked by NaCN. The nonenzymic NaN3 oxidization by hydrogen peroxide was not found in control experiments. NaN3 physiological activity dependent on NO-donating properties of this traditional inhibitor of heme-containing enzymes is discussed.

The role of nicotine in regulation of lymphocyte proliferation

Abstract: The effect of nicotine on both the expression of nicotinic acetylcholine receptors (nAChRs) and proliferation of hybridoma cells and normal mouse lymphocytes has been investigated. By means of immunoenzyme assay, nicotine was shown to regulate the number of nAChRs in both hybridoma cells and normal rat splenocytes. According to the data of triazolyl blue inclusion and ELISpot assay, nicotine stimulated proliferation of both hybridoma cells and normal plasma cells generated in the course of immune response in vivo. The cell sensitivity to nicotine depended on the number of nAChRs expressed on the membrane, as well as on their functional activity affected, in particular, by adhesive contacts. The use of the open channel blocker benzohexonium revealed that proliferative signal through nAChR in hybridoma cells was mediated by ion channel opening. The data obtained demonstrate the proproliferative role of nicotine for B lymphocytes, and may account for the development of lymphoproliferative disorders in tobacco smokers.