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The metabolic profile of plasma of white non-linear rats was investigated under normal conditions and after chronic inhalational exposure to low doses of aliphatic hydrocarbons with the number of carbon atoms from 6 to 10. Metabolic profile was determined with combination of gas chromatography-mass spectrometry and high performance, high resolution liquid chromatography-mass spectrometry with subsequent use of chemometrical methods for data treatment and presentation. It was shown that continuous 90-day exposure to a mixture of C₆-C₁₀ saturated hydrocarbons at concentration of 160 ± 20.5 mg/m³ results in various impairments of metabolic processes in liver and kidneys. Exposure to hydrocarbons at doses of 31.4 ± 5.6 mg/m³ and 5.2 ± 1.8 mg/m³ evoked significantly smaller changes. Novel metabolic markers of the toxic effect of low concentrations of C₆-C₁₀ aliphatic hydrocarbons were revealed. The ratio of concentrations of pyrophosphoric and oxalic acids in rat blood plasma was found to be the most sensitive marker called <>. A hypothesis is put forward about the redox balance violation as the leading pathogenetic mechanism of neuropathies and concomitant pathologies associated with hydrocarbon chronic intoxication.

The blocker of two-pore channels trans-NED 19 and hydrogen peroxide were found to inhibit histamine-induced relaxation of rat-aorta. The degree of inhibition depended on histamine concentration. The relaxation in response to I μM histamine of rat aorta preconstricted with 30 mM KCI, serotonin, or endothelin- 1, was completely abolished by 30 μM trans-NED 19. On the other hand, trans-NED 19 decreased the relaxation of the aorta in the presence of 10 μM histamine only by 2.1-fold to 2.4-fold, and there was almost no inhibition by trans-NED 19 of the relaxationinduced by 100 ptM histamine.) Relaxation of precontracted with serotonin aorta in response to 10 and 100 μM histamine was reduced by hydrogen peroxide (200 M) by 10- and 2.5-fold, respectively. Suppression of aorta relaxation by trans-NED 19 and H202 correlated with their inhibitory effect on the histamine-induced increase in the cytoplasmic free calcium concentration in human umbilical vein endothelial cells. With the use of a fluorescent probe LysoTracker, the cis-NED19 binding sites were demonstrated to be localized in endolysosomes of the endothelial cells. These data indicate that two-pore calcium channels participate in the histamine-induced endothelium-dependent relaxation of rat aorta. Furthermore, their functional role is exhibited much more clearly at low histamine concentrations. We suggest that hydrogen peroxide evokes depletion of intracellular calcium depots thereby suppressing the response to histamine.

Albumin molecule, unlike molecules of many other plasma proteins, is not covered with carbohydrate shell. It plays a crucial role in maintaining of colloid osmotic pressure of the blood, and is able to bind and transport various endogenous and exogenous molecules. The enzymatic activity of albumin, the existence and the role of which most researchers are still skeptical to accept, is of the main interest to us. In this review, a history of the issue is traced, with particular attention to the esterase activity of albumin. The kinetic and thermodynamic characteristics of the interaction of albumin with some substrates are adduced, and possibility of albumin being attributed to certain groups of Enzyme Nomenclature is considered.

The ratio of early apoptosis and late apoptosis (necrosis) in the cultured human umbilical vein endothelial cells was estimated after exposure to hydrogen peroxide (H2O2) in vitro trying to keep them close to the physiological conditions (high cell density, high serum content, H2O2 concentration not over 500 μM). Cell viability was assessed using flow cytometry and simultaneous staining with fluorescent dyes PO-PRO-1 to detect early apoptotic cells, and DRAQ7 to detect late apoptotic and necrotic cells. The data obtained suggest that the primary mechanism of cytotoxic response is apoptosis. The critical concentration of H2O2 causing the death of the cell population in a dense monolayer is 250 μM. Lower concentrations of H2O2 (up to 200 μM) cause death of individual cells; however, viability of endothelial cell population is retained, and response to calcium activating agonists does not change compared with control cells.

It is known that albumin is able to cut ester bonds in organophosphates (OPs). Amino acids responsible for esterase and pseudo-esterase activity of albumin towards OPs are still not determined. The purpose of this study is to identify the potential sites of esterase activity of albumin by the example of its interaction with soman using molecular modeling methods. The structures of the protein complexes with soman was determined by molecular docking procedure, the stability of the complexes were simulated using molecular dynamics method. It has been determined that productive sorption of soman near Tyr411 is possible only after deprotonation of the tyrosine. Tyr150 binds soman more efficiently than Tyr411; deprotonation of Tyr150 does not affect the binding efficiency, but affects on the stability of the complexes. The true esterase activity of albumin Tyr150 in relation to soman is proposed. It is shown that Ser193 can also be responsible for the esterase activity of albumin. We hypothesize that deprotonation of catalytic amino acid in one of the sites could be initiated by ligand binding in other sites (allosteric regulation).

Previously it was found that sodium fluoroacetate (SF) inhibited the growth of the Ehrlich cancer by means of monotherapy and enhanced the antitumor effect of cyclophosphamide (CP) in experiments with autochthonous subcutaneous tumors induced by benzo (a) pyrene. In this study a comparison of the antitumor activity of SF and metformin showed that both substances did not have significant effect in monotherapy but enhanced the effect of CP, increasing the percentage of tumors with the same or reduced volume. Besides, SF, unlike metformin increased the average duration of effect. The data obtained promoted further study of the mechanism of the antitumor effect of SF and the search effective combination with already known antitumor drugs.

Serotonin in cardiovascular system plays an important role in blood coagulation, allergy, and inflammation, as well as in blood vessel tone regulation. In this review, the mechanisms of serotonin effects upon the cells of blood vessels are considered and the list of main agonists and antagonists is presented. The signaling pathways activated by serotonin and their interaction in normal and pathological states are described.

Effects of biogenic and abiogenic disulphides on viability of human umbilical vein endothelial cells in culture has been investigated using three methods: the neutral red uptake assay, quantification of intracellular ATP, and modifications of Mosmann method, the essence of which is the reduction of tetrazolium salts, MTT and MTS, by cells. 2,2'-dithio-bis(N,N-diethyl)ethanamine (DS) was used as an abiogenic disulphide. As for biogenic disulphides, we used GSSG and garlic oil (GO), the principal component of which is diallyl disulphide (DADS). It has been found that DS and GO have a similar cytotoxic effect upon the endothelial cells (EC50 - 0.6 mM). GSSG in concentrations up to 1 mM did not effect the viability of endothelial cells. It has been demonstrated for the first time that DS and GO can serve as mediators of plasma membrane oxidoreductase activity, tetrazolium salts being as the substrate; this may cause false-negative effect. Thus, the Mosmann method has serious limitations when testing the cytotoxicity of disulphides, though can be used in studying the mechanism of action of disulphides.

The run of trained rats until exhaustion affected changes of red-ox balance in red blood cells (RBC) and deteriorated the acid stability of RBC. The oral administration of quercetin, 20 mg/kg, caused expansion of oxidative stress in RBC and a significant decrease in RBC acid stability. Pro-oxidant activity of quercetin could contribute accelerated intravascular hemolysis. It was accompanied by a significant reticulocytosis compared with a control group of rats no fed on antioxidant but exposed to run. Green tea extract (GTE) oral administration, 12 mg/kg, resulted in preventing oxidative stress in RBC, increasing in acid stability of RBC and reducing reticulocytosis. Thus, prooxidant activity of quercetin and the high antioxidant efficacy of GTE are indicative of the advantages of the complex preparations containing several antioxidant compounds. Such complex preparations may counteract an oxidative stress and save mechanical stability of erythrocytes under exhausted run.

Due to biochemical characteristics of toxic action of fluoroacetate on energetics and metabolism of cells, including tumor cells, it was interesting to testify sodium fluoroacetate (SFA) for its antitumor activity in vivo. We have estimated that SFA significantly inhibits growth of Ehrlich tumor carcinoma. In experiments with autochthonous induced by benzo[a]pyrene subcutaneous tumors, SFA was not active in monotherapy regime, though potentiated antitumor effect of cyclophosphamide, significantly increasing the relative number of mice with stabilized or decreased tumor volume as well as the duration of this effect. The data obtained render basis for additional studies of mechanism of antitumor effect of SFA.

Mass spectrum analysis revealed differences in general contents of low-molecular peptides spectrums in chemical weapons extermination object staffers, in comparison with the reference group. Findings are that serum paraoxonase activity in chemical weapons extermination object staffers in significantly increased.

Mitochondrial aconitase has been shown to be inactivated by a spectrum of substances or critical states. Fluoroacetate (FA) is the most known toxic agent inhibiting aconitase. The biochemistry of toxic action of FA is rather well understood, though no effective therapy has been proposed for the past six decades. In order to reveal novel approaches for possible antidotes to be developed, experiments were performed with rat liver mitochondria, Ehrlich ascite tumor cells and cardiomyocytes, exposed to FA or fluorocitrate in vitro. The effect of FA developed at much higher concentrations in comparison with fluorocitrate and was dependent upon respiratory substrates in experiments with mitochondria: with pyruvate, FA induced a slow oxidation and/or leak of pyridine nucleotides and inhibition of respiration. Oxidation of pyridine nucleotides was prevented by incubation of mitochondria with cyclosporin A. Studies of the pyridine nucleotides level and calcium response generated in Ehrlich ascite tumor cells under activation with ATP also revealed a loss of pyridine nucleotides from mitochondria resulting in a shift in the balance of mitochondrial and cytosolic NAD(P)H under exposure to FA. An increase of cytosolic [Ca2+] was observed in the cell lines exposed to FA and is explained by activation of plasma membrane calcium channels; this mechanism, could have an impact on amplitude and rate of Ca2+ waves in cardiomyocytes. Highlighting the reciprocal relationship between intracellular pyridine nucleotides and calcium balance, we discuss metabolic pathway modulation in the context of probable development of an effective therapy for FA poisoning and other inhibitors of aconitase.

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.

The application of hepatopancreas collagenase from crab Paralithodes camtschatica for the isolation and cultivation of the endothelial cells was studied in human umbilical vein endothelium. The comparison of the enzyme from crab hepatopancreas with collagenase from Clostridium histoliticum has shown that the number of viable cells isolated from human umbilical vein by the crab enzyme was lower than in the case of microbial collagenase. However, this difference was not significant for subsequent cultivation of cells. Harvesting of the endothelial cells from the substrate during cultivation was more effective in the case when collagenase from crab hepatopancreas was used. It was shown that crab collagenase, in contrast with microbiological collagenase, was not a metal-dependent enzyme.

The properties of beta-adrenoreceptors (beta-AR) have been studied in endothelial cells from the human pulmonary artery (EPA) and umbilical vein (EUV). [125I] Iodosyanopindolol binding assay revealed the amount of 22 and 12 fmol/10(6) cells as well as Kd = 92 and 52 pM for EPA and EUV, respectively. Adrenergic agonists increased the cAMP levels in EPA in the order of potency characteristic for beta 2-AR: isoproterenol greater than epinephrine greater than norepinephrine. Basing on the results obtained in the present study and the literature data a conclusion is made that the properties of beta-AR in vascular endothelial cells do not practically depend on their localization, suggesting universality of their function within the vascular system.