Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.6.99.3 (diaphorase)
5,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Concerning the well known stimulative effect of ethanol on the secretory activity of the intermediary lobe of the hypophysis in mature animals, the effect of the same agent was analyzed in the young of the alcoholized parents. Immediately after animals were parted from their alcoholized breast feeding mothers the hypophyses of the young old 1, 10, 20 and 30 days were taken for hystological analysis. In the first day of postnatal life the intermediary lobe is completely developed so that it has a glandular tissue covered by marginal epithelium; but structural changes connected with the influence of alcohol were not noticed. In the young old 10 days, the initial hyperplasia of the gland cells in the intermediary lobe was noticed and intermediocytes penetrated deep into the posterior lobe area. Histological findings at the 20th and 30th day of life are similar and manifested through the prominent hyperplasia of the glandular cells and through the hyperfunction certified by a rich content of intermediocytes in the RNA and the intensified activity of succinate-dehydrogenase and NADH diaphorase at the level of the marginal epithelium. The fact that the intermediary lobe cells are not able to react on the alcohol stimulation before the 10th day of life could be explained by the immaturity of the neurotransmitter system.
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PMID:[The effect of alcohol on the intermediate hypophyseal lobe in the early postnatal period]. 263 84

Methods of disaggregation of human placental tissue were assessed with the aim of maximising the yield of cytotrophoblast cells and minimising contamination with other cell types. Brief exposure to crude trypsin was found to be the best way to balance yield of trophoblast cells against contamination by cells of the villous core. Much higher yields of all cell types could be obtained by digestion with other enzymes. Staining for NADH diaphorase activity coupled with general morphology was found to be a reasonably specific, rapid and simple method of distinguishing cytotrophoblast cells in disaggregated mixtures. Alkaline phosphatase activity was an unreliable marker of trophoblast tissue in early placentas, and of the putative cytotrophoblast cells in mixtures of disaggregated cells. Cultures of cells obtained from term placentas were fairly homogeneous, whereas placentas of 6-12 weeks gestation gave heterogeneous cell cultures which became overgrown with fibroblasts.
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PMID:Human placental cytotrophoblast cells: identification and culture. 267 72

Naturally occurring quinones and quinone-containing extracts of seeds of the toxic plant Cassia obtusifolia (sicklepod) affected muscle mitochondrial function. Aqueous suspensions and organic extracts of C. obtusifolia seeds slightly elevated plasma creatine kinase levels of Sprague-Dawley rats. These extracts were analyzed by fused silica capillary gas chromatography and found to contain nine anthraquinones and three anthrones. Urinary metabolites primarily consisted of beta-glucuronide conjugates of the anthraquinones. The three anthrones or conjugate analogues were not present in the urine in detectable amounts. Emodin, doxorubicin and organic extracts of C. obtusifolia inhibited NADH:cytochrome c oxidoreductase activity of bovine heart mitochondrial particles and NADH:CoQ oxidoreductase activity of porcine heart mitochondrial NADH dehydrogenase, whereas juglone was stimulatory. Relative quinone metabolism correlated with semiquinone formation rate and with redox potential. A protective effect of coenzyme Q against enzyme inhibition by anthraquinones was also observed.
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PMID:Effects of Cassia obtusifolia (sicklepod) extracts and anthraquinones on muscle mitochondrial function. 274 52

Considerable evidence suggests that the release of iron from ferritin is a reductive process. A role in this process has been proposed for two hepatic enzymes, namely xanthine oxidoreductase and an NADH oxidoreductase. The abilities of xanthine and NADH to serve as a source of reducing power for the enzyme-mediated release of ferritin iron (ferrireductase activity) were compared with turkey liver and rat liver homogenates. The maximal velocity (Vmax.) for the reaction with NADH was 50 times greater than with xanthine; however, the substrate concentration required to achieve half-maximal velocity (Km) was 1000 times less with xanthine than with NADH. NADPH could be substituted for NADH with little loss in activity. Dicoumarol did not inhibit the reaction with NADH or NADPH, demonstrating that the ferrireductase activity with those substrates was not the result of the liver enzyme 'DT-diaphorase' [NAD(P)H dehydrogenase (quinone)]. A flavin nucleotide was required for ferrireductase activity with rat and turkey liver cytosol when xanthine, NADH or NADPH was used as the reducing substrate. FMN yielded twice the activity with NADH or NADPH, whereas FAD was twice as effective with xanthine as substrate. Kinetic comparisons, differences in lability and partial chromatographic resolution of the ferrireductase activities with the two types of reducing substrates strongly indicate that the ferrireductase activities with xanthine and NADH are catalysed by separate enzyme systems contained in liver cytosol. Complete inhibition by allopurinol of the ferrireductase activity endogenous to undialysed liver cytosol preparations and the ability of xanthine to restore equivalent activity to dialysed preparations indicate that the source of reducing power for the endogenous activity is xanthine. These studies suggest that xanthine, NADH or NADPH can serve as a source of reducing power for the enzyme-mediated reduction of ferritin iron, with a flavin nucleotide serving as the shuttle of electrons from the enzymes to the ferritin iron.
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PMID:The mobilization of ferritin iron by liver cytosol. A comparison of xanthine and NADH as reducing substrates. 277 99

Cardiac mitochondrial NADH dehydrogenase (Cytochrome c reductase, EC1.6.99.3) catalyses the reduction of ferricytochrome c to ferrocytochrome c by NADH. In the presence of the anthracycline anti-tumour drug, adriamycin, electron transfer from NADH is subverted to dioxygen. Using the electron spin resonance technique of spin trapping with the spin trapping agent 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) adriamycin was found to stimulate the formation of superoxide and hydroxyl radicals in the NADH/NADH dehydrogenase reaction. Hydroxyl radical formation is dependent on the availability of trace amounts of redox active metal ions - particularly ferric ions. Trace amounts of ferric ions catalyse the formation of hydroxyl radicals by both superoxide-dependent and adriamycin-dependent one electron reduction of hydrogen peroxide. The metabolism of adriamycin by cardiac mitochondrial NADH dehydrogenase may be an important etiological factor in adriamycin-induced cardiotoxicity. It may be therapeutically beneficial to keep nonessential ferric/ferrous ions in the myocardium at minimum levels with siderophoric iron chelators - providing the anti-tumour activity of adriamycin is not impaired.
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PMID:Reduction of oxygen by NADH/NADH dehydrogenase in the presence of adriamycin. 285 Feb 70

Influence of a cold (10 degrees C) or warm (35 degrees C) environment and a high or low level of energy intake on respiratory enzyme activities has been investigated in porcine skeletal muscle. Scanning microdensitometry was used to measure the reaction products from mitochondrial enzymes in individual slow- and fast-twitch muscle fibres. A cold environment was found to increase the activity of succinate dehydrogenase in both types of muscle fibre (P less than 0.001 for dark fibres, P less than 0.01 for light fibres) from young growing animals. Enzyme activity was also increased in animals on a low compared with a high energy intake (P less than 0.01) when living at 10 degrees C but not at 35 degrees C. Similar findings were obtained for NADH diaphorase and cytochrome oxidase aa3. The numbers of slow-twitch muscle fibres also increased after exposure to cold (P less than 0.01) and as a result of a low energy intake (P less than 0.01). These results are similar to those obtained in other species after exercise or as a result of peripheral arterial insufficiency. The extent to which they could be related to local tissue hypoxia or to changes in metabolic hormones is discussed.
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PMID:Influence of environmental temperature and energy intake on skeletal muscle respiratory enzymes and morphology. 285 42

Methylthioketobutyric acid has been used as an indicator for the production of reactive oxygen species during incubation with xanthine oxidase or NADH diaphorase in the presence of an autooxidizable quinone. The production of OH-radical-type oxidants is enhanced in the presence of crocidolite but not by the asbestos types chrysotile or amosite. This activity of crocidolite in the diaphorase system is further stimulated by bisulfite. Crocidolite-dependent ethylene formation from methylthioketo-butyric acid is inhibited by both superoxide dismutase and catalase. In the presence of both crocidolite and bisulfite, however, the inhibition by superoxide dismutase is preserved, but the inhibition by catalase is lost. Since in some respect the NADH-diaphorase quinone system may reflect the situation in the activated macrophage, crocidolite activation may represent a biochemical model system describing potential asbestos toxicity.
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PMID:Cooperative stimulation by sulfite and crocidolite asbestos fibres of enzyme catalyzed production of reactive oxygen species. 285 63

In a population of cultured rat liver epithelial cells transformed by 11 brief treatments with N-methyl-N'-nitro-N-nitrosoguanidine, 9% of the cells stained intensely for gamma-glutamyl transpeptidase (GGT). We have isolated from this phenotypically heterogeneous tumorigenic cell population 11 GGT-positive and 7 GGT-negative clonal subpopulations (from single cells) and have analyzed the ploidy and selected biochemical, histochemical, and growth properties of the cells in these clonal sublines. As compared to the GGT-negative strains and normal diploid rat liver epithelial cells, cells of the GGT-positive strains are larger in size, have greater DNA content, proliferate more slowly in culture, and have higher specific activities of NADH diaphorase, glucose-6-phosphate dehydrogenase, pyruvate kinase, and lactate dehydrogenase. The GGT-positive strains also show greater alteration and heterogeneity than do the GGT-negative strains in their ability to store glycogen and in their expression of lactate dehydrogenase isozymes. The results indicate that enzymatic changes commonly observed in "altered" hepatocytes in rat livers exposed to chemical carcinogens in vivo can also be produced in vitro in cultured hepatic epithelial cells by treatment with carcinogens. Moreover, treatment of a cell line with a chemical carcinogen generates a population of cells vastly heterogeneous in both their phenotypes and genotypes. Isolation of clonal subpopulations from the resulting cell line allows critical examination of the linkage and mechanistic relationship between tumorigenicity and many paratumorigenic phenotypes.
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PMID:Clonal isolation of populations of gamma-glutamyl transpeptidase-positive and -negative cells from rat liver epithelial cells chemically transformed in vitro. 286 91

Clonal subpopulations of a chemically induced tumorigenic rat liver epithelial cell line were analyzed for their cellular, biochemical, and in vitro growth properties and their tumorigenicity after injection into day-old newborn isogeneic rats. The phenotypic properties studied included DNA content; growth rate in culture; activities of gamma-glutamyl transpeptidase, NADH diaphorase, pyruvate kinase, glucose-6-phosphate dehydrogenase, and lactate dehydrogenase; ability to grow in calcium-poor medium; and ability to form colonies in soft agar. The results show that none of these phenotypes cosegregates with tumorigenicity and therefore is not reliable as a "marker" phenotype for neoplastic transformation in cultured rat liver epithelial cells. The poor correlations, either qualitatively or quantitatively, between paratumorigenic phenotypes and tumorigenicity suggest that neoplastic transformation in these cells involves a specific transforming gene locus or loci and that in vitro paratumorigenic phenotypes are merely epiphenomena of neoplastic transformation and progression. This study further reveals that the efficiency of the tumorigenicity assay of cultured rat liver epithelial cells in isogeneic newborn rats can be considerably improved by incubating the cells in medium containing only trace amounts of serum prior to transplantation into the host animals.
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PMID:Clonal analysis of tumorigenicity and paratumorigenic phenotypes in rat liver epithelial cells chemically transformed in vitro. 286 92

The muscle fiber types and sizes in the M. stapedius (middle ear muscle) of the domestic chicken, Gallus gallus were determined histochemically on the basis of their reactions to myofibrillar adenosine triphosphatase (mATPase), succinic dehydrogenase and NADH diaphorase. Only type II fibers were identified at pH 9.4 and 4.2. At pH 4.6 three levels of activity were seen: high, intermediate and low. With the staining techniques three subtypes of fibers for oxidative enzymes, Types II1 (highly glycolytic), II12 (intermediately glycolytic and lipolytic) and II123 (highly lipolytic) were identified. Fiber diameter was also measured for the different fiber types. The average fiber diameter was around 20 micron for each fiber type. Although similar in size, the fiber types were markedly different in their histochemical properties. These findings plus those of earlier physiological studies suggest that the M. stapedius of G. gallus is a fast twitch, muscle with fibers of similar diameter showing mainly fatigue resistance characteristics.
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PMID:A histochemical characterization of muscle fiber types in the avian M. stapedius. 288 51


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