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)

Citrulline formation by the interferon-gamma/lipopolysaccharide-inducible murine macrophage nitric oxide synthase is inhibited reversibly by imidazole, 1-phenylimidazole, 4-phenylimidazole, and 2-phenylimidazole with IC50 values of 40 microM, 6 microM, 225 microM, and > 1 mM, respectively. 1-Phenylimidazole inhibited the maximal velocity of citrulline formation but did not alter the concentration of arginine providing half-maximal activity. 1-Phenylimidazole inhibited citrulline formation by the murine macrophage nitric oxide synthase competitively versus (6R)-5,6,7,8-tetrahydro-L-biopterin (THB) with a Ki value of 0.7 microM, but inhibited citrulline formation by Ca(2+)-calmodulin-dependent nitric oxide synthase from GH3 pituitary cells noncompetitively versus THB with a Ki value of 40 microM. Imidazole inhibited citrulline formation by the murine macrophage nitric oxide synthase noncompetitively versus THB with a Ki value of 48 microM. Neither imidazole nor 1-phenylimidazole inhibited the cytochrome c reductase activity of murine macrophage nitric oxide synthase at concentrations 100-fold higher than their IC50 values for inhibiting citrulline formation. The antifungal imidazoles miconazole, ketoconazole, and clotrimazole did not inhibit either citrulline formation or cytochrome c reduction by murine macrophage nitric oxide synthase at concentration as high as 200 microM. Ca(2+)-calmodulin-dependent nitric oxide synthase from GH3 pituitary cells exhibited a Kact for THB of 80 nM, while the inducible murine macrophage nitric oxide synthase exhibited a Kact of 8 microM.
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PMID:Interferon-gamma-inducible murine macrophage nitric oxide synthase: studies on the mechanism of inhibition by imidazole agents. 751 12

Citrulline formation by Ca(2+)-calmodulin (CaM)-dependent nitric oxide synthase from bovine brain is inhibited reversibly by indazole, 5-nitro-, 6-nitro-, and 7-nitroindazole with IC50 values of 2.3 mM, 1.15 mM, 40 microM, and 2.5 microM, respectively. Inhibition of citrulline formation by 7-nitroindazole exhibited a Ki value of 0.16 microM and was competitive versus both arginine substrate and (6R)-5,6,7,8-tetrahydrobiopterin cofactor. The NADPH oxidase activity of bovine brain CaM-dependent nitric oxide synthase was inhibited by 7-nitroindazole with an IC50 value of 0.6 microM. Citrulline formation by the interferon-gamma/lipopolysaccharide-inducible nitric oxide synthase of murine macrophages (264.7 cell line) is inhibited reversibly by indazole, 5-nitro-, 6-nitro-, and 7-nitroindazole with IC50 values of 470, 240, 56, and 20 microM, respectively. Inhibition of citrulline formation by 7-nitroindazole exhibited a Ki value of 1.6 microM and was noncompetitive versus arginine substrate but competitive versus (6R)-5,6,7,8-tetrahydrobiopterin cofactor. None of the indazoles tested inhibited the cytochrome c reductase activity of either nitric oxide synthase isoform at concentrations up to 1000-fold higher than their IC50 values for inhibition of citrulline formation. These observations are consistent with the proposal that the indazoles exert their inhibitory actions by interaction with the heme-iron of nitric oxide synthase such that oxygen does not bind.
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PMID:The inhibition of the constitutive and inducible nitric oxide synthase isoforms by indazole agents. 751 13

The Ca(2+)-independent form of nitric oxide synthase was induced in rat neonatal astrocytes in primary culture by incubation with lipopolysaccharide (1 microgram/ml) plus interferon-gamma (100 U/ml), and the activities of the mitochondrial respiratory chain components were assessed. Incubation for 18 h produced 25% inhibition of cytochrome c oxidase activity. NADH-ubiquinone-1 reductase (complex I) and succinate-cytochrome c reductase (complex II-III) activities were not affected. Prolonged incubation for 36 h gave rise to a 56% reduction of cytochrome c oxidase activity and a 35% reduction in succinate-cytochrome c reductase activity, but NADH-ubiquinone-1 reductase activity was unchanged. Citrate synthase activity was not affected by any of these conditions. The inhibition of the activities of these mitochondrial respiratory chain complexes was prevented by incubation in the presence of the specific nitric oxide synthase inhibitor NG-monomethyl-L-arginine. The lipopolysaccharide/interferon-gamma treatment of the astrocytes produced an increase in glycolysis and lactate formation. These results suggest that inhibition of the mitochondrial respiratory chain after induction of astrocytic nitric oxide synthase may represent a mechanism for nitric oxide-mediated neurotoxicity.
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PMID:Nitric oxide-mediated inhibition of the mitochondrial respiratory chain in cultured astrocytes. 751 65

The principal goal of the present study was to test the hypothesis that cytokines modulate glucose transport in skeletal muscle by increasing nitric oxide production. Cultured L6 skeletal muscle cells were incubated in the presence of tumour necrosis factor-alpha, interferon-gamma or lipopolysaccharide (LPS) alone or in combination for 24 h. Neither cytokines nor LPS alone induced NO production, as measured by nitrite concentrations in the medium. However, when used in combination, the two cytokines significantly stimulated NO production, and this effect was synergistically enhanced by the presence of LPS. Reverse transcriptase-PCR (RT-PCR) analysis revealed that NO release was associated with the induction of inducible (macrophage-type) NO synthase (iNOS). The increase in iNOS expression was confirmed at the protein level by Western-blot analysis and NADPH/diaphorase histochemical staining. Cytokines and LPS markedly increased basal glucose transport in L6 myocytes. Insulin also stimulated basal glucose transport, but significantly less in cells chronically exposed to cytokines/LPS. The sensitivity of L6 muscle cells to insulin-stimulated glucose transport was also significantly decreased by cytokines/LPS treatment. The NOS inhibitor NG-nitro-l-arginine methyl ester (l-NAME) inhibited nitrite production in cytokine/LPS-treated cells, and this prevented the increase in basal glucose transport and restored muscle cell responsiveness to insulin. Cytokines/LPS exposure significantly increased GLUT1 transporter protein levels but decreased GLUT4 expression in L6 cells. l-NAME treatment prevented the increase in GLUT1 protein content but failed to restore GLUT4 transporter levels. These results demonstrate that cytokines and LPS affect glucose transport and insulin action by inducing iNOS expression and NO production in skeletal muscle cells. The data further indicate that cytokines and LPS increase the expression of the GLUT1 transporter protein by an NO-dependent mechanism.
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PMID:Cytokines modulate glucose transport in skeletal muscle by inducing the expression of inducible nitric oxide synthase. 923 Jan 32

Application of delta-aminolevulinic acid (ALA) results in the endogenous accumulation of protoporphyrin IX and is a useful approach in the photodynamic therapy (PDT) of cancers. To investigate the role of nitric oxide (NO) in the specific accumulation of protoporphyrin and ALA-induced PDT of cancerous cells, we transfected inducible-nitric oxide synthase (NOS2) cDNA into human embryonic kidney (HEK) 293T cells and examined the ALA-induced photo-damage as well as the accumulation of porphyrin in the cells. When the NOS2-expressing HEK293T cells were treated with ALA and then exposed to visible light, they became more sensitive to the light with accumulating porphyrins, as compared with the ALA-treated control cells. An increase in the generation of NO in transfected cells led to the accumulation of protoporphyrin with a concomitant decrease of ferrochelatase, the final step enzyme of heme biosynthesis. When mouse macrophage-like RAW264.7 cells were cultured with lipopolysaccharide and interferon-gamma, the expression of NOS2 was induced. The addition of ALA to these cells led to the accumulation of protoporphyrin and cell death upon exposure to light. The treatment of cells with an NOS inhibitor, NG-monomethyl-L-arginine acetate, resulted in the inhibition of protoporphyrin accumulation and cell death. The levels of mitochondrial ferrochelatase and rotenone-sensitive NADH dehydrogenase in the NOS2-induced cells decreased. These results indicated that the generation of NO augments the ALA-induced accumulation of protoporphyrin IX and subsequent photo-damage in cancerous cells by decreasing the levels of mitochondrial iron-containing enzymes. Based on the fact that the production of NO in cancerous cells is elevated, NO in the cells is responsible for susceptibility with ALA-induced PDT.
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PMID:The role of nitric oxide in delta-aminolevulinic acid (ALA)-induced photosensitivity of cancerous cells. 1719 60

Clinicopathogenetic impact of cycloferon, an endogenous interferon inductor, on the process of Astrakhan rikettsial fever, its complications and outcomes was analysed. The treatment scheme with addition of cycloferon to the complex therapy was optimized. The specificity of the disease clinical process and the level of the interferon status in the patients treated with cycloferon alone or with combination of the standard therapy and cycloferon was shown. It was observed that in the patients with moderate severity of the disease the combined use of the standard therapy and cycloferon was in favour of arresting the disease clinical signs (fever, headache, weakness, eruption, hepatomegaly, arthralgia and myalgia, lymphatic gland inflammation, primary affect) and lowered the hospitalization term vs. the standard therapy alone. In the patients with moderate severity of the disease the levels of the serous interferon-alpha before the treatment were found lower, while those of interferon-gamma were higher. The use of cycloferon in the treatment scheme resulted in increase of the interferon-alpha levels and decrease of the higher levels of interferon-gamma. The standard therapy in combination with cycloferon in the patients with moderate severity of the disease provided changes in the immune status: increase of the relative content of T- and B-lymphocytes and normalization of their absolute number. Normalization of the phagocytic activity and the coefficient of the active phagocytes, as well as increase of the phagocytic index, the levels of immunoglobulins G, A and M and the number of the circulating immune cells were stated. The standard therapy with addition of cycloferon resulted in normalization of the levels not only of succinic denydrogenase, lactate dehydrogenase and glucose-6-dehydrogenase but also of alpha-naphthylacetate esterase and alpha-naphthylbutirate esterase in the neutrophils, as well as of the whole spectrum of the monocyte enzymes, except NAD-diaphorase. The adverse reactions were observed in 2.5% of the cases (9 subjects). All of them were mild and did not require discontinuation of the drugs use.
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PMID:[Evaluation of safety and pharmacotherapeutic efficacy of cycloferon in treatment of Astrakhan rickettsial fever]. 2274 Nov 99