[Antioxidant status and glutathione redox potential of erythrocytes in patients with acute coronary syndrome].

Indicators of oxidative stress (OS), systemic inflammation, metabolism and redox status of glutathione (GSH) were investigated and compared in patients with ST-segment elevation myocardial infarction on electrocardiograms (STEMI), and patients with unstable angina (UA). The elevated and decreased myeloperoxidase level, superoxide dismutase activity, and moderate increased plasma levels of interleukin-6, while maintaining the antioxidant potential, were found in Group 1. Disorders in pro-/antioxidant balance and systemic inflammatory response were manifested in UA. Increased GSH concentration (and total GSH) in erythrocytes has been established for STEMI patients and the decreased GSH for UA patients. Thus, a significant shift of erythrocytes redox to oxidization and increase (unlike STEMI patients) of glutathione peroxidase activity were recorded. Mechanisms of the pro- and antioxidant functions of red blood cells in acute coronary syndrome are considered. The role of red blood cell glutathione to provide more oxidized intravascular environment for S-glutathionylation and optimization of redox signaling in target cells is pronounced.

[Coenzyme A biosynthesis as universal mechanism of conjugation of exogenous and multiple pantothenic acid functions]. / Biosintez kofermenta A--universal'nyi mekhanizm sopriazheniia ékzogennosti i mnozhestvennosti funktsii pantotenovoi kisloty.

Development of Academician R. V. Chagovets' ideas of the regulatory role of vitamins and their derivatives in thiol-containing compound metabolism and antioxidant system formation as well as in studying non-coenzymatic functions of B-vitamins and vitamin-binding proteins had a considerable effect on the almost 40-year studies on pantothenic acid metabolism and biochemical functions by scholars at the vitaminologic school in Grodno. The concept concerning the intracellular structure of the pantothenate coenzyme form, CoA, pool (content and ratio of CoA-SH, acetyl-CoA, short-chain and long-chain acyls-CoA, coenzyme disulfide forms and CoA-S-S-proteins) was substantiated as an important metabolic regulatory factor (including glutathione system redox potential), with changes being a principal mechanism of pantothenate derivative vitamin and pharmacotherapeutic activity implementation. The effect of the latter is mediated through the systems of CoA biosynthesis and phosphopantetheine proteins, changed CoA-S-S-protein levels, which in turn maintain the intracellular level of CoA-SH as well as cytosolic and mitochondrial transport of its vitamin-containing precursors. A universal CoA biosynthetic function was revealed in prevention of lipid peroxidation initiation and oxidative stress development.

Protection by pantothenol and beta-carotene against liver damage produced by low-dose gamma radiation.

Rats were exposed to a total dose of 0.75 Gy of gamma radiation from a 60Co source, receiving three doses of 0.25 Gy at weekly intervals. During two days before each irradiation, the animals received daily intragastric doses of 26 mg pantothenol or 15 mg beta-carotene per kg body mass. The animals were killed after the third irradiation session, and their blood and livers were analyzed. As found previously (Slyshenkov, V.S., Omelyanchik, S.N., Moiseenok, A.G., Trebukhina, R.V. & Wojtczak, L. (1998) Free Radical Biol. Med. 24, 894-899), in livers of animals not supplied with either pantothenol or beta-carotene and killed one hour after the irradiation, a large accumulation of lipid peroxidation products, as conjugated dienes, ketotrienes and thiobarbituric acid-reactive substances, could be observed. The contents of CoA, pantothenic acid, total phospholipids, total glutathione and GSH/GSSG ratio were considerably decreased, whereas the NAD/NADH ratio was increased. All these effects were alleviated in animals supplied with beta-carotene and were completely abolished in animals supplied with pantothenol. In the present paper, we extended our observations of irradiation effects over a period of up to 7 days after the last irradiation session. We found that most of these changes, with the exception of GSH/GSSG ratio, disappeared spontaneously, whereas supplementation with beta-carotene shortened the time required for the normalization of biochemical parameters. In addition, we found that the activities of glutathione reductase, glutathione peroxidase, catalase and NADP-dependent malate (decarboxylating) dehydrogenase ('malic enzyme') in liver were also significantly decreased one hour after irradiation but returned to the normal level within 7 days. Little or no decrease in these activities, already 1 h after the irradiation, could be seen in animals supplemented with either beta-carotene or pantothenol. It is concluded that pantothenol is an excellent radioprotective agent against low-dose gamma radiation.

[Characteristics of pantothenic acid transport in membrane vesicles of the brush border of small intestine epithelial cells in rats]. / Kharakteristiki transporta pantotenovoi kisloty v membrannykh vezikulakh shchetochnoi kaimy épitelial'nykh kletok tonkoi kishki krys.

A microfiltration method was used to study the mechanism of pantothenic acid transport in the membrane vesicles of the rat small intestine brush margin. The vitamin uptake proceeded to inner space of the vesicles and was enhanced in presence of sodium ions. The findings suggest that the vitamin transport across the membrane of the small intestine brush margin is mediated by a carrier and proceeds via a Na(+)-co-transport mechanism.

Pantothenol protects rats against some deleterious effects of gamma radiation.

Rats were exposed to gamma radiation from a 60Co source, receiving 0.25 Gy at weekly intervals. During 2 d before each irradiation, the animals received daily intragastric doses of 26 mg pantothenol or 15 mg beta-carotene per kg body weight. One hour after the third irradiation session, the animals were killed and their livers were analyzed. In animals not supplied with pantothenol, the irradiation resulted in a significant decrease of total liver lipids and a 50% decrease in phospholipids. Liver cholesterol was decreased by about 20%. Irradiation produced lipid peroxidation as expressed by doubling of the amounts of conjugated dienes and ketone dienes and of thiobarbituric acid reactive compounds. The amount of CoA in liver was decreased by 24% and that of reduced glutathione by 40%. The NAD+/NADH ratio was increased by 60% and the activity of NADP-dependent malate dehydrogenase (decarboxylating) was decreased by 26%. The amount of pantothenic acid and its derivatives (expressed as pantolactone-generating compounds) in blood decreased by about 80%. In rats to which pantothenol was administered, the content of pantothenic acid in blood was tripled compared to nonirradiated (control) rats, and all the biochemical parameters measured in liver were the same as in nonirradiated animals.

Some natural and synthetic antioxidants as stabilizers of beta-carotene conversion into vitamin A.

The effect of antioxidants (vitamins C and E, quercetin, probucol, butylated hydroxytoluene) on the oxidation of beta-carotene and its conversion into retinal under the influence of beta-carotene 15,15'- dioxygenase (CDO) from rat intestinal mucosa was studied. The activity of CDO decreased in the presence of oxidants. Antioxidants protected both the substrate and the enzyme. The extent of the protection depended on the antioxidant type. The combined injection of antioxidants and beta-carotene to animals completely or partially prevented the inhibition of the intestinal CDO which was caused by products of non-enzymatic oxidation of beta-carotene. Vitamins C and E, which protected the enzyme--substrate complex in vivo and in vitro, were found to be the most efficient protectors of beta-carotene conversion into retinal.

Noxious effects of oxygen reactive species on energy-coupling processes in Ehrlich ascites tumor mitochondria and the protection by pantothenic acid.

Irradiation of Ehrlich ascites tumor cells with ultraviolet light or exposure to the Fenton reaction results in lesions in the mitochondrial energy-coupling system. Formation of the membrane potential and its utilization for ATP synthesis are more affected than the respiratory chain. Preincubation of the cells with pantothenic acid or its derivatives which can serve as precursors of CoA largely protects against the damage of mitochondrial energetics by oxygen reactive species formed by UV light or the Fenton reaction. Incubation of Ehrlich ascites tumor cells with pantothenic acid increases their content of glutathione (most of which is present in the reduced form) by 40%. It is concluded that the protective effect of precursors of CoA against lesions of the mitochondrial energy-coupling system by oxygen reactive species is mainly due to removal of free radicals and peroxides by glutathione peroxidase and phospholipid hydroperoxide glutathione peroxidase.

Pantothenic acid and its derivatives protect Ehrlich ascites tumor cells against lipid peroxidation.

Preincubation of Ehrlich ascites tumor cells at 22 or 32 degrees C, but not at 0 degree C, with pantothenic acid, 4'-phosphopantothenic acid, pantothenol, or pantethine reduced lipid peroxidation (measured by production of thiobarbituric acid-reactive compounds) induced by the Fenton reaction (Fe2+ + H2O2) and partly protected the plasma membrane against the leakiness to cytoplasmic proteins produced by the same reagent. Pantothenic acid and its derivatives did not inhibit (Fe2+ + H2O2)-induced peroxidation of phospholipid multilamellar vesicles, thus indicating that their effect on the cells was not due to the scavenging mechanism. Homopantothenic acid and its 4'-phosphate ester (which are not precursors of CoA) neither protected Ehrlich ascites tumor cells against lipid peroxidation nor prevented plasma membrane leakiness under the same conditions. Incubation of the cells with pantothenic acid, 4'-phosphopantothenic acid, pantothenol, or pantethine significantly increased the amount of cellular CoA and potentiated incorporation of added palmitate into phospholipids and cholesterol esters. It is concluded that pantothenic acid and its related compounds protect the plasma membrane of Ehrlich ascites tumor cells against the damage by oxygen free radicals due to increasing cellular level of CoA. The latter compound may act by diminishing propagation of lipid peroxidation and promoting repair mechanisms, mainly the synthesis of phospholipids.

[Possible ways of regulating detoxifying processes in the alcohol dehydrogenase reaction with pantothenic acid derivatives]. / Vozmozhnye puti reguliatsii proizvodnymi pantotenovoi kisloty dezintoksikatsionnykh protsessov v alkogol'degidrogenaznoi reaktsii.

Oxidation of derivatives and precursors of pantothenic acid was studied in alcohol dehydrogenase reactions. Despite the presence of free hydroxymethyl groups in a number of pantothenic acid derivatives only panthenol with Km = 8 x 10(-3) M was shown to serve as a substrate for alcohol dehydrogenase from horse liver tissue (EC 1.1.1.1) Pantethine, sodium phosphopantothenate, CoA and acetyl-CoA decreased the rate of ethanol oxidation, where pantethine and sodium phosphopantothenate were competitive inhibitors, while CoA and acetyl-CoA inhibited the enzyme noncompetitively Ki = 1.2 x 10(-2) M, 2.1 x 10(-2) M, 4.4 x 10(-4) M and 5.1 x 10(-4) M, respectively. Metabolic precursors, which were different from pantothenic acid in their structure, were not involved in the alcohol dehydrogenase reaction. Possible regulation of alcohol intoxication using derivatives and precursors of vitamin B3 is discussed.

[Purification and various properties of pantothenate kinase from the rat liver]. / Ochistka i nekotorye svoistva pantotenatkinazy iz pecheni krys.

Homogeneous (according to disc gel electrophoresis data) ATP: D-pantothenate-4'-phosphotransferase (pantothenate kinase, EC 2.7.1.33) was obtained from rat liver cytosol of heterogeneous stock rats. The enzyme was purified 199-fold with a 9.3% yield. The enzyme was relatively unstable but retained its activity in the presence of 10% glycerol containing 5.10(-4) M ATP over 10 days at 4 degrees C. The pH optimum was 6.5; the apparent Km values were equal to 1.2 X 10(-5) M and 1.4 X 10(-3) M for pantothenate and ATP, respectively, at the ATP/Mg2+ ratio of 1. Pantetheine produced a competitive inhibition of pantothenate kinase. Pantethine or pantetheine disulfide did not inhibit the enzyme.

[Distribution and biotransformation of labelled pantothenate in cytoplasmic and mitochondrial fractions of the rat liver with a deficiency of pantothenic acid]. / Raspredelenie i biotransformatsiia mechenogo pantotenata v tsitoplazmaticheskoi i mitokhondrial'noi fraktsii pecheni krys s nedostatochnost'iu pantotenovoi kisloty.

Experiments were conducted on white rats given synthetic rations devoid of pantothenic acid during 10 weeks. Intensification of 14C-pantothenate deposition was recorded 30 min and 4 h after its intraperitoneal administration. The mitochondrial fraction of the liver accumulated the isotope in time. High-performance liquid chromatography used for separation of the vitamin labeled metabolites has revealed phosphopantothenate (pantothenate), phosphopantothein, CoA and dephospho-CoA (pantetein) in the liver homogenate, while in the mitochondria extracts only CoA and dephospho-CoA (pantetein) were detected. It has been suggested that dephosphorylation of pantothenate metabolites and rapid transformation of phosphopantetein into CoA may take place during the separation of the fractions.

[Thiamine diphosphate pool and its biosynthesis in the liver in galactosamine hepatitis]. / Pul tiamindifosfata i ego biosintez v pecheni pri galaktozaminovom gepatite.

The hepatitis-like changes were induced in the liver of albino female rats weighing 120-150 g and fed on the appropriate vivarium diet by single parenteral administration of hydrochloride galactosamine in a dose of 0.9 or 1.8 mmol per 1 kg of body weight. The thiamine diphosphate level in the cytosol fraction of the liver decreased 24 h after the preparation administration, the same in blood but with the higher dose used. The activity of pyruvate dehydrogenase, a thiamine diphosphate dependent enzyme, decreased similarly. The cytosol transketolase activity lowered by 38-39%. The coenzyme biosynthesis disturbance due to a fall by 49-58% in the thiamine pyrophosphatase activity is considered to be responsible for hydrochloride galactosamine-induced decrease in the thiamine diphosphate pool. Specificity of the thiamine diphosphate pool disturbance and discoordination of thiamine diphosphate dependent enzymes in the liver are observed under administration of hydrochloride galactosamine.

[Effect of phosphopantothenate on the biosynthesis of cholesterol and its esters from various precursors in the liver of db/db mice]. / Deistvie fosfopantotenata na biosintez kholesterina i ego efirov iz razlichnykh predshestvennikov v pecheni myshei db/db.

It was found that in the livers of db/db mice with hyperinsulinemia, obesity and non-insulin-dependent diabetes the rates of cholesterol biosynthesis from pyruvate and, to a lesser extent, from acetate and mevalonate as well as of cholesterol ester biosynthesis from pyruvate (but not from acetate and mevalonate) are increased. Presumably, the observed changes are mediated by structural alterations in the CoA reserves, i.e., increase of free CoA to short-chain acyl-CoA and free CoA to long-chain fatty acyl-CoA indices, and of the ratio between enzymatic activities of generation and utilization of NADPH. Treatment of db/db mice with phosphopantothenate, besides eliciting changes in the CoA reserves structure towards normalization and inhibition of NADP-dependent dehydrogenases and pyruvate and 2-oxoglutarate dehydrogenase complexes, causes the diminution of cholesterol and its ester levels in the liver in the absence of any conspicuous changes in the rates of their biosynthesis from pyruvate.

[The protective effect of pantothenic acid derivatives and changes in the system of acetyl CoA metabolism in acute ethanol poisoning]. / Zashchitnyi éffekt proizvodnykh pantotenovoi kisloty i izmeneniia sistemy metabolizma atsetil-KoA pri ostroi intoksikatsii étanolom.

Calcium pantothenate (CaP), calcium 4'-phosphopantothenate (CaPP), pantethine, panthenol, sulfopantetheine and CoA decrease acute toxicity of acetaldehyde in mice. All studied compounds diminish duration of the narcotic action of ethanol--ET (3.5 g/kg intraperitoneally) in mice and rats. In the latter this effect is realized at the expense of "long sleeping" and "middle sleeping" animals. CaP (150 mg/kg subcutaneously) and CaPP (100 mg/kg subcutaneously) prevent hypothermia and a decrease of oxygen consumption in rats induced by ET administration. Combined administration of ET, CaP and CaPP leads to a characteristic increase of acid-soluble CoA fractions in the rat liver and a relative decrease of acetyl CoA synthetase and N-acetyltransferase reactions. The antitoxic effect of preparations of pantothenic acid is not mediated by CoA-dependent reactions of detoxication, but most probably is due to intensification of ET oxidation and perhaps to its elimination from the organism.

[Phosphoprotein phosphatase nonspecifically hydrolyzes CoA]. / Fosfoproteinfosfataza nespetsificheski gidrolizuet CoA.

CoA hydrolysis was studied by a homogenous phosphoprotein phosphatase (EC 3.1 3.16) preparation from bovine spleen nuclei at pH 5.8. Phosphoprotein phosphatase catalyzed hydrolysis of the CoA 3'-phosphoester bond to form dephospho-CoA and Pi. The Km value for phosphoprotein phosphatase with CoA as substrate was 3.7 mM, the specific activity - 0.26 mmol Pi.min-1.mg-1. Phosphoprotein phosphatase did not essentially catalyze the calcium pantothenate hydrolysis (not more than 2% as compared with the CoA hydrolysis rate).

[Enzyme systems of the substrate and cofactor supply of hyperlipogenesis in non-insulin-dependent diabetes]. / Fermentnye sistemy substratnogo i kofaktornogo obespecheniia giperlipogeneza pri insulinnezavisimom diabete.

Enzymatic systems of hepatic hyperlipogenesis supply by substrate (acetyl-CoA) and cofactors (NADPH and ATP) were studied in experiments on diabetic C57Bl/Ks J mice (db/db) that served as a model of non-insulin dependent diabetes. The rise in acetyl-CoA synthetase activity catalyzing the primary step of lipogenesis from acetate has been found, while pyruvate dehydrogenase complex activity did not differ from the control and ATP-citrate lyase activity was lowered. Hyperlipogenesis in non-insulin dependent diabetes was induced by the activation of cellular energy supply revealed in enhanced 2-oxoglutarate dehydrogenase activity and elevated ATP level, as well as changes in the activity ratio of NADPH supply and utilization and the rise in fructose-1,6-diphosphate, allosteric effector of fatty acid synthetase, which resulted in the increase of the enzyme activity and created wider potentials of NADPH utilization as a reducing equivalent in lipogenesis.

[Ultrasonic coagulometry as a method of testing compounds with antiplasmin activity]. / Ul'trazvukovaia koagulometriia kak sposob testirovaniia soedinenii s antiplazminovoi aktivnost'iu.

An ultrasonic interferometer has been used to study the process of fibrin clot lysis according to the decrease in the rate of propagation of an ultrasonic wave in the latter. A significant decrease in the sound fall rate on adding epsilon-aminocaproic and trans-4-aminomethylcyclohexanecarbonic acids to the system indicates their activity inhibiting fibrinolysis. N-nicotinoyl derivatives of this compounds possess less pronounced antiplasmin activity.

[Active transport of pantothenic acid in the small intestine of the rat]. / Aktivnyi transport pantotenovoi kisloty v tonkom kishechnike krys.

Pantotheric acid transport non-linear dependence was found in vivo and in vitro tests in the rat small intestine. Kinetic constants of the above process were determined. Dinitrophenol, sodium fluoride, anoxia, 4-phosphopantothenate and pantoilaminocaproic acid inhibited vitamin transfer against concentration gradient. Dependence of pantothenate transport rate upon sodium concentration was revealed.