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Biomedical subjects

M V Ivanova

Publications and source records attributed to M V Ivanova.

At least 19 recordsLinked to original sources
PubMed2001

Antioxidant properties, autooxidation, and mutagenic activity of echinochrome a compared with its etherified derivative.

Antioxidant properties of 2,3,5,7,8-pentahydroxy-6-ethyl-1,4-naphthoquinone (echinochrome A) were linked with the scavenging of peroxy radicals in liposomes, trapping of superoxide anion radicals, and binding of ferrous ions to inactive complexes in the aqueous phase. The antioxidant property of 6-ethyl-2,3,7-trimethoxy-5,8-dihydroxy-1,4-naphthoquinone (trimethoxyechinochrome A) was negligible. Autooxidation of echinochrome A was increased in basic media according to the degree of its dissociation. Autooxidation of polyvalent anions in basic media was accompanied by generation of naphthosemiquinone and superoxide anion radicals as free radical intermediates. An increased rate of echinochrome A autooxidation was noted in the presence of calcium ions. This was explained by a shift of pK of Ca2+-echinochrome A complexes toward acidic pH comparably with echinochrome A. Echinochrome A possessed pronounced mutagenic activity, while trimethoxyechinochrome A was inactive in the Salmonella/mammalian microsome reverse mutation assay (Ames test) for all examined cells (TA98, TA100, TA1537). Comparison of the chemical and biological activity of echinochrome A and trimethoxyechinochrome A demonstrated the key role of the beta-hydroxyl groups in the 2nd, 3rd, and 7th naphthol cycle positions. The O2-* and naphthosemiquinone radicals generated in the redox transition of 2,3-oxygroups may be the reason for the strongly pronounced mutagenicity of echinochrome A.

Animals↗
PubMed2001

Diffuse liver lesions among the general population of western Siberia.

The study was aimed at ascertaining the prevalence of diffuse liver lesions and associated factors in the general population of Novosibirsk, Western Siberia. A representative sample of 362 men and 870 women aged 25-64 years was investigated using ultrasound examination and blood tests for liver-derived enzymes (AST, ALT, GGT). Diffuse liver lesions (DLL) were detected in 42.8% of males and 18.7% of females. A significant association was found between DLL and elevated levels of liver enzymes. In conclusion, the prevalence of chronic liver disease is relatively frequent in the unselected urban population.

Adult↗
PubMed2000

Interactions between the soluble domain I of nicotinamide nucleotide transhydrogenase from Rhodospirillum rubrum and transhydrogenase from Escherichia coli. Effects on catalytic and H+-pumping activities.

Nicotinamide nucleotide transhydrogenase from Escherichia coli is composed of two subunits, the alpha and the beta subunits, each of which contains a hydrophilic domain, domain I and III, respectively, as well as several transmembrane helices, collectively denoted domain II. The interactions between domain I from Rhodospirillum rubrum (rrI) and the intact or the protease-treated enzyme from E. coli was investigated using the separately expressed and purified domain I from R. rubrum, and His-tagged intact and trypsin-treated E. coli transhydrogenase. Despite harsh treatments with, e.g. detergents and denaturing agents, the alpha and beta subunits remained tightly associated. A monoclonal antibody directed towards the alpha subunit was strongly inhibitory, an effect that was relieved by added rrI. In addition, rrI also reactivated the trypsin-digested E. coli enzyme in which domain I had been partly removed. This suggests that the hydrophilic domains I and III are not in permanent contact but are mobile during catalysis while being anchored to domain II. Replacement of domain I of intact, as well as trypsin-digested, E. coli transhydrogenase with rrI resulted in a markedly different pH dependence of the cyclic reduction of 3-acetyl-pyridine-NAD+ by NADH in the presence of NADP(H), suggesting that the protonation of one or more protonable groups in domain I is controlling this reaction. The reverse reaction and proton pumping showed a less pronounced change in pH dependence, demonstrating the regulatory role of domain II in these reactions.

Amino Acid Sequence↗
PubMed2000

[Prevalence of and risk factors for gallstones in female population of Novosibirsk].

AIM: To investigate the prevalence of gallstones and associated factors in female population of Novosibirsk (Western Siberia). MATERIALS AND METHODS: A representative sample of 870 women aged 25-64 years was drawn from general population according to WHO "MONICA" protocol. The subjects were screened for the presence of gallstones by gallbladder ultrasonography, completed a questionnaire relating to food and alcohol consumption, smoking, gastrointestinal symptoms and obstetric history. They also underwent physical examination and blood chemistry tests. Age-adjusted prevalence of cholelithiasis was 9.5%. Increasing age, obesity, diabetes mellitus, consumption of animal fat, pregnancies and opisthorchiasis positively correlated with gallstones in univariate analysis. Serum lipids, family history of gallstones, consumption of alcohol and tobacco were not predictors of gallstones. Only association with age and obesity was significant in multivariate analysis. Among subjects with cholelithiasis 52.1% were not aware of having gallstones. Subjects with gallstones more frequently suffered from biliary colics and non-specific dyspeptic symptoms. However, their predictive value was poor. Cholecystectomized patients revealed more often upper abdominal pain and dyspeptic symptoms. CONCLUSION: Prevalence and risk factors for gallstones in female population of Novosibirsk are similar to those reported in Western European countries. Cholecystectomy is not recommended in patients with symptomless disease.

Adult↗
PubMed2000

[Identification of Escherichia coli nitrate reductase as an antigen for a monoclonal antibody with previously unknown specificity].

The immunoaffinity chromatography of total membrane proteins from Escherichia coli helped determine the specificity of the monoclonal antibody 3A6 that was obtained upon immunization of mice with nicotinamide nucleotide transhydrogenase preparations and reacted with an unknown E. coli antigen. Proteins with apparent molecular masses of 150, 45, and 20 kDa were isolated and identified by N-terminal sequencing as the subunits of nitrate reductase. This conclusion was confirmed by immunoblotting with the 3A6 antibody of the proteins from the E. coli cells grown upon induction of nitrate reductase. It was shown that the 3A6 antibody specifically recognizes the alpha subunit of nitrate reductase, and the formation of the enzyme-antibody complex does not result in a loss of the enzyme catalytic activity.

Animals↗
PubMed1999

[Ednit influence on oxidation resistance of LDL lipoproteins in hypertensive subjects].

AIM: Evaluation of resistance of low density lipoproteins (LDLP) of the serum to oxidation in patients with essential hypertension (EH) before and after course treatment with ednit. MATERIALS AND METHODS: 10 patients with mild or moderate EH aged 38-58 years were given ednit for 1 or 2 months. 10 healthy males aged 35-48 years served control. RESULTS: EH patients had high baseline levels of lipid peroxidation products in LDLP, while antioxidant resistance of LDPL was diminished by 67% (p < 0.05) compared to controls. Ednit treatment for 1 and 2 months enhanced this resistance in mild and moderate EH (p < 0.05). CONCLUSION: Ednit raises resistance of LDLP to oxidation and as ACE inhibitor lowers arterial pressure. Therefore it can be used in EH.

Adult↗
PubMed1999

Interaction of natural polyhydroxy-1,4-naphthoquinones with superoxide anion-radical.

The interaction of natural polyhydroxy-1,4-naphthoquinones (PHNQ) with superoxide anion-radical (O2) was studied by UV--visible spectrophotometry. 3-Acetyl-2,6,7-trihydroxynaphthazarin (spinochrome C), 2,3,7-trihydroxynaphthazarin (spinochrome D), 2,3,6, 7-tetrahydroxynaphthazarin (spinochrome E), 6-ethyl-2,3, 7-trihydroxynaphthazarin (echinochrome A), 6-ethyl-2,3, 7-trimethoxynaphthazarin (trimethoxyechinochrome A), and 2, 3-dihydroxy-6,7-dimethylnaphthazarin (A618) were tested. Xanthine and xanthine oxidase were used to generate **O2. The interaction with O2 led to significant time-dependent changes in the spectra of echinochrome A and spinochromes D and E. There was a weak influence of O2 on the spinochrome C spectrum and no change in the trimethoxyechinochrome A spectrum. The spectra that were transforming during the time of the reaction contained a pronounced isobestic point. This indicates that a single reaction product is being formed. We suggest that 1,2,3,4-tetraketones are formed from 2, 3,5,8-tetrahydroxy-1,4-naphthoquinones (echinochrome A and spinochromes D and E) via O2-induced oxidation of their OH-groups in the 2nd and 3rd positions. Reaction constants were determined by a competitive method using nitro blue tetrazolium (NBT). The reaction constants were about 104-105 M-1.sec-1. They decreased in the sequence: echinochrome A > spinochrome D > spinochrome C > NBT > trimethoxyechinochrome A. Thus, we conclude that some of the natural PHNQ containing hydroxyl groups in the 2nd and 3rd positions may act as powerful superoxide anion-radical scavengers.

Acids↗
PubMed1997

[Monoclonal antibodies to the alpha-subunit of the putative human H+,K+-ATPase encoded by the atp1al1 gene].

The N-terminal fragment of ATP1AL1, the possible catalytic subunit of human ouabain-sensitive H+,K(+)-ATPase, was expressed in Escherichia coli cells as two recombinant proteins: the Ser14-Ile104 fragment or the same fragment containing His6 sequence at its N-end. The second protein was purified by metal-affinity chromatography and used as an antigen to construct two hybridoma lines producing antibodies of the IgM class. These monoclonal antibodies were shown to recognize not only the starting antigen but also the full-size recombinant ATP1AL1 protein and do not react with Na+,K(+)-ATPase.

Amino Acid Sequence↗
PubMed1997

[Effects of laser therapy on lipids and antioxidants in blood of patients with bronchial asthma].

Laser therapy was assessed for effects on lipoperoxides and free radical catchers in blood lipids of patients with bronchial asthma (BA). When a group of 52 BA patients was compared to healthy donors by dienic conjugates, vitamin E and overall lipid-soluble antioxidants levels in the whole blood and plasma, these appeared higher in the asthmatics. Combination of laser therapy with conventional treatment returned these parameters close to normal.

Adult↗
PubMed1994

Interaction of tocopherol with peroxyl radicals does not lead to the formation of lipid hydroperoxides in liposomes.

alpha-Tocopherol (alpha-TOH) is thought to act as a lipid-soluble antioxidant by scavenging the chain-carrying lipid peroxyl radical (LOO.), giving rise to alpha-TO. and LOOH. The aim of the present work is to test the possibility that alpha-TOH may also exert a protective action by converting LOO. into the parent, unoxidized lipid molecule (LH) with concomitant formation of O2- and T+O. To assess the relative contribution of the two pathways, the amounts of products accumulating were measured, i.e. LOOH and O2-, under conditions where lipid peroxidation was initiated at linear rates by the UV light-induced decomposition of AIBN. The overall conclusion of the study is based on the observation that significant amounts of O2- were produced, whereas the delta LOOH/delta alpha-TOH was considerably smaller than 1.0. A mechanism of one or two-electron oxidation of TOH is considered; according to it the phospholipid primary structure is restored (LOO.-->LH, breaking of the C-->O bond). This leads to the oxygen or superoxide anion-radical release accordingly.

Antioxidants↗
PubMed1993

[Creation of Delta mu(H)+ equal to 250 mV on the inner mitochondrial membrane is necessary, but not a sufficient condition for ATP synthesis].

Electron transport in the NADH-ferricyanide and succinate-->O2 chains and ATP synthesis in mitochondria under different incubation conditions have been studied. Ferricyanide which substitutes oxygen as a terminal acceptor provides the generation on the membrane potential, delta microH+, but does not initiate the functioning of the proton cycle. It is suggested that mitochondria can utilize delta microH+ only during the functioning of the redox chain under aerobic conditions. Presumably, under normal conditions oxygen implements two (but not one) functions; the second function of O2 may consist in the formation of a superoxide radical anion. Under conditions of decoupling caused by the free radical scavenger propylgallate, the ATP synthesis in mitochondria may be stimulated de novo through superoxide generation. This effect is abolished by superoxide dismutase.

Adenosine Triphosphate↗