[Assessment of relationship of lipid and carbon profile indicators with vitamin D supply in children depending on body mass index].

Overweight children represent a particularly vulnerable group for hypovitaminosis D. Clinical studies on the relationship between vitamin D (VD) deficiency and metabolic risk factors for cardiovascular disorders are controversial, and for children of primary school age who have overweight and obesity are insufficient. The aim of the research was to study the relationship between lipid and carbohydrate metabolism indicators and VD status in children, depending on the body mass index. Material and methods. A cross-sectional (one-step) study was carried out on a sample of 154 children with different weight of 8-10 years old (74 girls, 80 boys). Three groups of research participants were identified: group 1 - 44 obese, group 2 - 58 overweight, group 3 - 52 children with normal body weight. For all children, the serum level of 25(OH)D, parathyroid hormone (PTH), calcium (Ca), phosphorus (P), alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), triglycerides (TG), ß-lipoproteins, glucose, insulin was determined, and Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) was also calculated. Results. VD deficiency in obese children was found almost 2.3 fold more often than in overweight (p=0.002) and 2.8 fold more often than in children with normal body weight (p=0.001). Indicators of lipid and carbohydrate metabolism were within physiological limits. However, in obese children they significantly exceeded the indicator of healthy children (p<0.05). When comparing the results of biochemical studies, it was revealed that children with VD deficiency [25(OH)D <20 ng/ml] had statistically significantly higher medians of PTH, TC, TG, ALT, AST, glucose, insulin, HOMA-IR and lower P and Ca level compared with children with normal micronutrient blood content (p<0.05). The medians of ALT, AST, TC, ß-lipoproteins, TG, glucose, insulin and HOMA-IR levels in obese children with VD deficiency were statistically significantly higher than in children with normal body weight and VD deficiency and in healthy children with an optimal concentration of 25(OH)D. At the same time, there was no statistically significant difference between the indicators of lipid and carbohydrate metabolism in the group of healthy children with normal VD status and its deficiency. Conclusion. VD deficiency is an important predictor of obesity complications and it exacerbates the risk of cardiometabolic disorders in children who are obese in the early school years.

[Markers of the course of obliterating atherosclerosis of lower limb arteries]. / Markery techeniia obliteriruiushchego ateroskleroza arterii nizhnikh konechnostei.

AIM: The purpose of the study was to determine the level of substances damaging the vascular endothelium, as well as to assess their effect on the functional state of the endothelium and the course of obliterating atherosclerosis of lower limb arteries. PATIENTS AND METHODS: The study included a total of 112 people, subdivided into three groups: those with an unfavourable course of obliterating atherosclerosis of lower limbs arteries (n=48) - group 1, patients with obliterating atherosclerosis of lower limbs arteries with a conventionally favourable course (n=48) - group 2, and apparently healthy volunteers (n=16). In all subjects, the following parameters were analysed: stable metabolites of nitric oxide II, endothelin-1, homocysteine and basal insulin. RESULTS: The level of stable nitric oxide metabolites (p<0.001 as compared with group 1; p<0.045 compared with group 2) was lower in the groups of patients with obliterating atherosclerosis of lower limb arteries (88.5±7.3 µmol/L in group 1; 161.5±8.6 µmol/L in group 2) as compared with healthy volunteers (226.0±28.6 µmol/L). In its turn, the level of nitric oxide was statistically significantly lower (p<0.001) in group 1 patients as compared with those of group 2. The level of endothelin-1 turned out to be higher (p<0.001) in group 1 (2.1±0.1 ng/ml) as compared with group 2 (1.6±0.1 ng/ml). Comparing group 1 patients with healthy volunteers (1.4±0.1 ng/ml), the level of endothelin-1 had also higher values (p<0.001). The level of endothelin-1 did not differ (p=0.270) as compared with group 2 and healthy volunteers. Comparing the homocysteine level in patients of the examined groups (20.7±0.8 µmol/L in group 1 patients and 18.1±0.6 µmol/L in group 2 patients) with healthy volunteers (13.0±0.4 µmol/L) demonstrated an increase in the parameters (p<0.001). The level of homocysteine turned out to be higher in group 1 patients than in those of group 2 (p<0.001). The level of basal insulin turned out to be significantly higher in the studied groups of patients with obliterating atherosclerosis of lower limb arteries (24.9±4.6 mIU/L in group 1; 8.0±0.7 mIU/L in group 2) than in healthy volunteers (5.1±0.5 mIU/L). Statistically significant (p<0.001) hyperinsulinemia was observed in group 1 as compared with group 2. CONCLUSION: Hyperhomocysteinemia and hyperinsulinemia are predictors of an unfavourable course of the disease. In a high level of these parameters, one may predict an unfavourable course of obliterating atherosclerosis of lower limb arteries.

Role of NUDIX Hydrolases in NAD and ADP-Ribose Metabolism in Mammals.

Proteins of the NUDIX hydrolase (NUDT) superfamily that cleave organic pyrophosphates are found in all classes of organisms, from archaea and bacteria to higher eukaryotes. In mammals, NUDTs exhibit a wide range of functions and are characterized by different substrate specificity and intracellular localization. They control the concentration of various metabolites in the cell, including key regulatory molecules such as nicotinamide adenine dinucleotide (NAD), ADP-ribose, and their derivatives. In this review, we discuss the role of NUDT proteins in the metabolism of NAD and ADP-ribose in human and animal cells.

The Regulatory Role of NAD in Human and Animal Cells.

Nicotinamide adenine dinucleotide (NAD) and its phosphorylated form NADP are the major coenzymes in the redox reactions of various essential metabolic pathways. NAD+ also serves as a substrate for several families of regulatory proteins, such as protein deacetylases (sirtuins), ADP-ribosyltransferases, and poly(ADP-ribose) polymerases, that control vital cell processes including gene expression, DNA repair, apoptosis, mitochondrial biogenesis, unfolded protein response, and many others. NAD+ is also a precursor for calcium-mobilizing secondary messengers. Proper regulation of these NAD-dependent metabolic and signaling pathways depends on how efficiently cells can maintain their NAD levels. Generally, mammalian cells regulate their NAD supply through biosynthesis from the precursors delivered with the diet: nicotinamide and nicotinic acid (vitamin B3), as well as nicotinamide riboside and nicotinic acid riboside. Administration of NAD precursors has been demonstrated to restore NAD levels in tissues (i.e., to produce beneficial therapeutic effects) in preclinical models of various diseases, such as neurodegenerative disorders, obesity, diabetes, and metabolic syndrome.

[Hepatoprotectors in treatment of alcoholic liver disease].

The best hepatoprotective effect has combined appointment Essentiale forte N, Heptral and Apilak at rats with chronic alcohol intoxication. Use of these drugs is characterized by minor morphological changes in structure of liver and constant biochemical parameters.

[Studies in chicken genetics: commemorating the 120th anniversary of the outstanding Soviet geneticist A. S. Serebrovsky (1892-1948)].

The paper highlights the research of A. S. Serebrovsky in chicken genetics, including gene mapping and inheritance of morphological traits. Genetic formulas for several breeds are presented. The data of genetic surveys for local chicken populations from 23 regions of the former Soviet Union are also reviewed. The personal data of the authors on the morphotypological characteristics of different chicken breeds are given and discussed.

[Mitochondrial and lysosomal pathways of death of hepatocytes of lamprey Lampetra fluviatilis L].

Mechanisms of mitochondrial and lysosomal pathways of natural cell death in lamprey hepatocytes at the spring period of prespawning migration are described. The mitochondrial pathways (release of cytochrome c from mitochondria into cytosol and activation ofcaspases) operates according to the classical scheme known for apoptosis. The lysosomal cell death pathway connected with activation of cathepsin B has been revealed quite recently in cells in pathologies, in particular at obstruction of gallbladder and bile ducts. The peculiarity of lamprey hepatocytes consists in biliary atresia (the absence both of gallbladder and of bile ducts) in liver of adult animals. Thereby the lamprey hepatocytes represent an excellent object for study of this new pathway of cell death. We have revealed a parallel development of the mitochondrial and lysosomal pathways of cell death of lamprey hepatocytes.

[Accumulation of sodium and potassium ions in oocytes of the river lamprey Lampetra fluviatilis during prespawning period].

Accumulation of Na+ and K+ ions in oocytes of the river lamprey Lampetra fluviatilis and their transport across the plasma membrane is realized by two main mechanisms--Na,K-pump and Na,K,Cl-cotransport. At the prespawning period from December to May the intracellular Na+ concentration was observed to increase from 10 to 25 mM and the K+ concentration--from 28 to 45 mM. Results obtained on isolated oocytes with aid of 204Tl radioactive label have shown that contributions of the Na,K-pump and Na,K,Cl-cotransport to potassium accumulations were close until March. In spring, the total K+ inflow almost doubled owing to activation of the Na,K-pump, whereas contribution of Na,K,Cl-cotransport did not change. It seems that an increase of the intracellular content of the main inorganic cations in oocytes resulted in parallel activation of the Na,K-pump and probably of Na/H-exchange. The biological significance of activation of these mechanisms of ion transport at the prespawning period might be due to a necessity of accumulation of Na+ and K+ ions in concentrations optimal for subsequent embryonic development.

[Transport of monovalent thallium across the membrane of oocyte of the lamprey Lampetra fluviatilis].

Mechanisms of transport of monovalent thallium across the membrane of oocyte of the lamprey Lampetra fluviatilis were studied by using 204Tl. Transport of Tl+ in lamprey oocytes has been shown to be realized by at least two pathways: through Na/K-pump and by the mechanism of Na,K,Cl-cotransport. In the standard Ringer solution (mM): 4 KCl, 140 NaCl, 0.5 CaCl2, 5 glucose, 10 Tris-HCl--in the presence of oubain, the coefficient of the 204Tl stationary distribution (cell/medium) was within the range of 2.3-2.5, while the time necessary to reach its 50 % value amounted to 40-5 min at 20 degrees C. In potassium-free media, transport of 204Tl via Na/K-pump was described by simple kinetis with saturation and was characterized by the value V(max) = 520 pmol/(cell x h) and K(M) = 0.3 mM. In the presence of 4 mM K+ and 0.1 mM/l Tl+, the oubain-sensitive Tl+ flow decreased to 75 pmol/(cell x h). At activation of the mechanism of Na,K,Cl-cotransport by the outer Na+ (in Na-NMDG media of different composition) the total inflow of Tl+ reached 193 +/- 20 pmol/(cell x h), while the butamenide-sensitive component--119 +/- 12 pmol/(cell x h) with K(M) for Na+ about 20 mM. In the incubation media with variable concentration of chloride ions (replacement of Cl- by NO3(-)) the total Tl+ flow reached 220 +/- 21, while via the mechanisms of Na,K,Cl-cotransport--87 +/- 8 pmol/(cell x h). Under our experimental conditions, mechanisms of active transport and Na,K,Cl-cotransport accounted for 94% of the Tl+ inflow. The potassium channels that usually are also permeable to monovalent thallium ions were not revealed.

Crystal structures of two dimeric nickel di-phenyl-acetate com-plexes.

In the crystal structures of the title com-pounds, namely µ-aqua-κ2 O:O-di-µ-di-phenyl-acetato-κ4 O:O'-bis-[(di-phenyl-acetato-κO)bis-(pyridine-κN)nickel(II)], [Ni2(C14H11O2)4(C5H5N)4(H2O)] (1) and µ-aqua-κ2 O:O-di-µ-di-phenyl-acetato-κ4 O:O'-bis-[(2,2'-bi-pyridine-κ2 N,N')(di-phenyl-acetato-κO)nickel(II)]-aceto-nitrile-di-phenyl-acetic acid (1/2.5/1), [Ni2(C14H11O2)4(C10H8N2)2(H2O)]·2.5CH3CN·C14H12O2 (2), the com-plex units are stabilized by a variety of intra- and inter-molecular hydrogen bonds, as well as C-H⋯π and π-π contacts between the aromatic systems of the pyridine, dipyridyl and di-phenyl-acetate ligands. Despite the fact that the di-phenyl-acetate ligand is sterically bulky, this does not inter-fere with the formation of the described aqua-bridged dimeric core, even with a 2,2'-bi-pyridine ligand, which has a strong chelating effect.

Effect of acetate on transport of organic acid (fluorescein) in renal proximal tubules of frog.

The effect of acetate on active fluorescein transport in intact proximal tubules of surviving frog kidney was studied. When the kidneys were incubated in a 120 mM Na+ medium, 10 mM acetate stimulated fluorescein uptake in the tubules. The stimulation was more pronounced if the kidneys had been previously preincubated for 3 h in the substrate-free solution. Lowering of the Na+ concentration in the bathing medium to 10 mM resulted in the disappearance of the acetate effect. Preincubation of the kidneys with acetate at 2-4 degrees C gave rise to stimulation of the fluorescein transport only in the 120 mM Na+ acetate-free medium. The acetate effect on the fluorescein uptake was partially prevented by ouabain. The stimulation of the uptake by acetate in the 120 mM Na+ medium correlated with an increase in the extent of reduction of pyridine nucleotides in the tubules. The pyridine nucleotides were reduced more markedly after incubation of the kidneys in the 10 mM Na+ medium, when acetate had no effect on the fluorescein transport. In both the 120 MM and the 10 mM Na+ media, the cold preincubation of the kidneys with 2.5 mM ADP or 2.5 mM ATP resulted in only slight stimulation of the fluorescein uptake. But in both media the uptake was significantly enhanced after cold preincubation of the kidneys with 2 mM NADH. After the cold preincubation with ADP, stimulation of the fluorescein transport by acetate was observed in the case of the 10 mM Na+ medium also. The absence of any stimulatory effect of acetate on the organic acid transport in the 10 mM Na+ medium is explained as the result of the transformation of mitochondria in the tubular cells into the inactive state 4 due to a decrease in the intracellular ADP level. Reducing equivalents are supposed to take part in energization and/or regulation of transport processes in plasma membranes of the renal proximal tubules.

Structure and active transport in the plasma membrane of the tubules of frog kidney.

The active transport of organic anions through the plasma membrane of the proximal tubules of frog kidney was studied. For this purpose a marker anion, fluorescein, was used, its flow into the tubules registered by the increase of fluorescense. The kinetics of transport was measured as function of time, concentration of substrate, concentration of a competing acid (p-aminohippuric acid) and temperature. The process is inhibited by strophantin, a specific poison for (Na++K+)-dependent ATPase. These data show that fluorescein transport is effected with the participation of a charged carrier, probably by the downfield mechanism postulated by Mitchell. To confirm this mechanism, a passive flow of K+ was created inwards across the membrane of the proximal tubules by means of valinomycin. It led to the discharge of the membrane and to the inhibition of fluorescein transport. Anions are transported downfield across the membrane, probably in a state of complexes with two Na+ ions. A magnetic field of 10000-28000 oersted inhibits the fluorescein transport strongly. This can be regarded as a proof of the liquid-crystalline structure of biological membranes and demonstrates the importance of this structure for active transport.

On the active transport of organic acids (fluorescein) in the choroid plexus of the rabbit.

The kinetics of active transport of an organic acid (fluorescein) through the membranes of the choroid plexus from the lateral ventricules of the brain of rabbit was studied both morphologically and functionally. It was shown that fluorescein is actively translocated through the apical and basal membrane of the epithelium and is accumulated in blood capillaries at a concentration exceeding one order of magnitude that in the incubation medium. The kinetic curves displaying saturation and the demonstration of inhibition by other acids shows that a specific carrier is involved in the transfer across the membrane. The active transport of fluorescein at 20 degrees C was found to be sodium independent. Total exclusion of sodium from the incubation medium does not change the Michaelis constant (Km) and maximal velocity (V). The active transport depends on the operation of (Na+ + K+)-ATPase as energy source but obviously no specific complexes with the participation of sodium are involved.

Staurosporine-sensitive protein phosphorylation is required for postreplication DNA repair in human cells.

DNA repair is an important factor of stability of pro- and eukaryotic genomes which plays a central role in mutagenesis and carcinogenesis. Genetic control of nucleotide excision repair (NER) in mammalian cells is well studied, but little is known about molecular mechanisms of postreplication repair (PRR) which allows bypass of base lesions in template strands after DNA replication. In Saccharomyces cerevisiae PRR is controlled by the RAD61RAD18 pathway which involves POL30 gene encoding proliferating cell nuclear antigen (PCNA), and in human cells PCNA is known to be closely associated with the newly replicated chromatin where PRR probably takes place. In UV-irradiated human cells distinct PCNA foci may be detected in some cells which accumulate phosphorylated breast cancer susceptibility protein BRCA1 and another protein BARD1. Human PCNA is also known to be phosphorylated after UV-irradiation. In this study we found that the known inhibitor of protein kinases staurosporine supresses PRR in NER-deficient cells which is consistent with the view that BRCA1 and PCNA are required for PRR. We also have shown that the distinct PCNA foci in UV-irradiated NER-deficient cells are actually associated with the newly replicated chromatin. Since RAD18 protein is not essential for normal DNA replication and directly controls PRR in yeast, we analysed whether this protein as well as its human homologs (HR18A and HR18B) have common domains with BRCA1 and BARD1. It is found that HR18A has a subregion of homology to BARD1 and HR18A-to BRCA1. Taken together the results indicate that BRCA1 and BARD1 may be involved in PRR in human cells.

Stimulation of weak organic acid uptake in rat renal tubules by cadmium and nystatin.

The uphill uptake of a weak organic acid, fluorescein, in superficial proximal tubules of the rat kidney was stimulated by CdCl2 (0.1 mM) or nystatin (20 microM) in the absence of metabolic substrates in the incubation medium. The stimulation could be observed during the initial period of incubation (up to 30 min) only and was prevented completely by ouabain (0.1 mM), fluoroacetate (1 mM), malonate (10 mM), alpha-cyano-4-hydroxycinnamate (0.1 mM), phenylpyruvate (1 mM), D-malate (2 mM) or phenazine methosulfate (20 microM). In the renal cortex fragment suspension, both Cd2+ and nystatin increased the ouabain-sensitive, basal oxygen consumption and inhibited the rate of glucose production from pyruvate, but not from lactate. In the presence of lactate (0.5-5 mM) in the incubation medium, Cd2+ and nystatin rather inhibited fluorescein uptake, while externally added pyruvate did not influence their stimulatory effects. Taken together, these data suggest that both activation of the tricarboxylic acid cycle and export of reducing equivalents from the mitochondria to the cytosol are necessary for the stimulatory effects of Cd2+ and nystatin on the weak organic acid uptake to develop.

Stimulatory effect of ethanol on weak organic acid uptake in rat renal tubules.

Ethanol at relatively low concentrations (10-40 mM) significantly stimulated the uphill uptake of a weak organic acid, fluorescein, in the superficial proximal tubules of rat renal cortex slices, but it did not affect the rate of glucose production from lactate or pyruvate in rat renal cortex fragment suspension. In a low Na+ medium, ethanol failed to stimulate fluorescein uptake, although under the conditions employed in the present study, the baseline weak organic acid uptake was not dependent on external Na+. The stimulation of fluorescein uptake by ethanol (20 mM) was abolished by an inhibitor of alcohol dehydrogenase (EC 1.1.1.1), pyrazole (1 mM), or an inhibitor of aldehyde dehydrogenase (EC 1.2.1.3), cyanamide (0.3 mM), suggesting that oxidation of ethanol mediated its effect on the uptake. Among gluconeogenesis inhibitors tested, only D-malate (2 mM) abolished the stimulatory effect of ethanol, while the rest either did not affect (quinolinate) or even slightly augmented (alpha-cyano-4-hydroxycinnamate and phenylpyruvate) it. The effect of ethanol was markedly increased by an inhibitor of the tricarboxylic acid cycle, fluoroacetate. It was concluded that the stimulation by ethanol of weak organic acid uptake in rat renal tubules was mediated by the production of acetate.

Effects of inhibitors of gluconeogenesis on weak organic acid uptake in rat renal tubules.

Using inhibitors of gluconeogenesis (phenylpyruvate, alpha-cyano-4-hydroxycinnamate, quinolinate, D-malate, aminooxyacetate), we analysed mechanisms by which the gluconeogenic substrates, lactate and pyruvate, as well as a short-chain fatty acid, acetate, stimulate the uptake of a weak organic acid, fluorescein, in the rat kidney. We have shown that these inhibitors modified both the rate of glucose production from lactate and pyruvate in the renal cortex fragment suspension and the stimulatory effects of the metabolic substrates on fluorescein uptake in superficial proximal tubules in the renal cortex slices. The peculiarities of the effects of lactate and pyruvate on the uptake were correlated with the partial divergence of the pathways of gluconeogenesis from these precursors. The linkage of the weak organic acid uptake with gluconeogenesis is interpreted in terms of the hypothesis that the uptake is controlled by the cytoplasmic pyridine nucleotide redox potential, which is maintained with the participation of certain processes involved in glucose synthesis.