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)

The present study was aimed to evaluate the efficacy of L-arginine on mitochondrial function in ischemic and reperfusion (I/R) induced hepatic injury. Adult Wistar rat were subjected to 1 h of partial liver ischemia followed by 3 hour reperfusion. Eighteen wistar rats were divided into three groups viz. sham-operated control group (I) (n=6), ischemia and reperfusion (I/R) group (II) (n=6), L-arginine treated group (100 mg/kg body weight/daily by oral route for 7 days before induced ischemia reperfusion maneuver) (III) (n=6). Mitochondrial injury was assessed in terms of decreased (P<0.05) activities of mitochondrial antioxidant enzymes (GSH, SOD, CAT), respiratory marker enzymes (NADH dehydrogenase, cytochrome c oxidases) and hepatocytes nitric oxide production. Pre-treatment with L-arginine (10 mg/kg/p.o. for 7 days) significantly counteracted the alternations of hepatic enzymes and mitochondrial respiratory and antioxidant enzymes. In addition, electron microscopy and histopathology study showed the restoration of cellular normalcy and accredits the cytoprotective role of L-arginine against I/R induced hepatocellular injury. On the basis of these findings it may be concluded that L-arginine protects mitochondrial function in hepatic ischemic and reperfused liver.
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PMID:Attenuation of mitochondrial injury by L-arginine preconditioning of the liver. 1880 13

Ca2+ accumulation and Ca2+ overloading in mitochondria are responsible for the cell abnormality associated with ischemia and reperfusion injury. The present study was aimed at evaluating the efficacy of the Ca2+ channel blocker amlodipine on the mitochondrial Ca2+ accumulation, mitochondrial antioxidant status and mitochondrial respiratory enzymes in ischemia and reperfusion (I/R) induced liver injury. I/R injury induced mitochondrial damage in rats was assessed in terms of the decrease in activities (p < 0.05) of respiratory marker enzymes (malate dehydrogenase, succinate dehydrogenase and NADH dehydrogenase), mitochondrial antioxidant enzymes (glutathione, superoxide dismutase, catalase), and significant increase (p < 0.05) in the level of lipid peroxidation (LPO) and Ca2+ content.Mitochondrial damage was confirmed by transmission electron microscopic (TEM) examination. Pretreatment with amlodipine effectively counteracted the alteration in mitochondrial enzymes induced by ischemia-reperfusion liver damage. TEM study confirms the restoration of cellular normalcy and the cytoprotective role of amlodipine against I/R induced hepatic injury. On the basis of our findings it may be concluded that amlodipine not only possesses Ca2+ channel antagonist properties but it may also reduce the extent of mitochondrial damage by its antioxidant activity.
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PMID:Protective role of the calcium channel blocker amlodipine against mitochondrial injury in ischemia and reperfusion injury of rat liver. 1910 76

Dihydrolipoamide dehydrogenase (LADH) is a flavo-enzyme that serves as a subunit of alpha-ketoglutarate dehydrogenase complex (alpha-KGDHC). Reactive oxygen species (ROS) generation by alpha-KGDHC has been assigned to LADH (E3 subunit) and explained by the diaphorase activity of E3. Dysfunctions of alpha-KGDHC and concurrent ROS production have been implicated in neurodegeneration, ischemia-reperfusion, and other pathological conditions. In this work we investigated the in-depth details of ROS generation by isolated LADH and alpha-KGDHC. We found a parallel generation of superoxide and hydrogen peroxide by the E3 subunit of alpha-KGDHC which could be blocked by lipoic acid (LA) acting on a site upstream of the E3 subunit. The pathologically relevant ROS generation (at high NADH/NAD+ ratio and low pH) in the reverse mode of alpha-KGDHC could also be inhibited by LA. Our results contradict the previously proposed mechanism for pH-dependent ROS generation by LADH, showing no disassembling of the E3 functional homodimer at acidic pH using a physiologically relevant method for the examination. It is also suggested that LA could be beneficial in reducing the cell damage related to excessive ROS generation under pathological conditions.
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PMID:Inhibition of the alpha-ketoglutarate dehydrogenase-mediated reactive oxygen species generation by lipoic acid. 1939 31

The effect of ageing and the relationships between the catalytic properties of enzymes linked to Krebs' cycle, electron transfer chain, glutamate and aminoacid metabolism of cerebral cortex, a functional area very sensitive to both age and ischemia, were studied on mitochondria of adult and aged rats, after complete ischemia of 15 minutes duration. The maximum rate (Vmax) of the following enzyme activities: citrate synthase, malate dehydrogenase, succinate dehydrogenase for Krebs' cycle; NADH-cytochrome c reductase as total (integrated activity of Complex I-III), rotenone sensitive (Complex I) and cytochrome oxidase (Complex IV) for electron transfer chain; glutamate dehydrogenase, glutamate-oxaloacetate-and glutamate-pyruvate transaminases for glutamate metabolism were assayed in non-synaptic, perikaryal mitochondria and in two populations of intra-synaptic mitochondria, i.e., the light and heavy mitochondrial fraction. The results indicate that in normal, steady-state cerebral cortex, the value of the same enzyme activity markedly differs according (a) to the different populations of mitochondria, i.e., non-synaptic or intra-synaptic light and heavy, (b) and respect to ageing. After 15 min of complete ischemia, the enzyme activities of mitochondria located near the nucleus (perikaryal mitochondria) and in synaptic structures (intra-synaptic mitochondria) of the cerebral tissue were substantially modified by ischemia. Non-synaptic mitochondria seem to be more affected by ischemia in adult and particularly in aged animals than the intra-synaptic light and heavy mitochondria. The observed modifications in enzyme activities reflect the metabolic state of the tissue at each specific experimental condition, as shown by comparative evaluation with respect to the content of energy-linked metabolites and substrates. The derangements in enzyme activities due to ischemia is greater in aged than in adult animals and especially the non-synaptic and the intra-synaptic light mitochondria seems to be more affected in aged animals. These data allow the hypothesis that the observed modifications of catalytic activities in non-synaptic and intra-synaptic mitochondrial enzyme systems linked to energy metabolism, amino acids and glutamate metabolism are primary responsible for the physiopathological responses of cerebral tissue to complete cerebral ischemia for 15 min duration during ageing.
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PMID:Effect of ageing and ischemia on enzymatic activities linked to Krebs' cycle, electron transfer chain, glutamate and aminoacids metabolism of free and intrasynaptic mitochondria of cerebral cortex. 1949 70

Diazoxide, a mitochondrial ATP-sensitive potassium (mitoK(ATP)) channel opener, protects the heart from ischemia-reperfusion injury. Diazoxide also inhibits mitochondrial complex II-dependent respiration in addition to its preconditioning effect. However, there are no prior studies of the role of diazoxide on post-ischemic myocardial oxygenation. In the current study, we determined the effect of diazoxide on the suppression of post-ischemic myocardial tissue hyperoxygenation in vivo, superoxide (O(2)(-*)) generation in isolated mitochondria, and impairment of the interaction between complex II and complex III in purified mitochondrial proteins. It was observed that diazoxide totally suppressed the post-ischemic myocardial hyperoxygenation. With succinate but not glutamate/malate as the substrate, diazoxide significantly increased ubisemiquinone-dependent O(2)(-*) generation, which was not blocked by 5-HD and glibenclamide. Using a model system, the super complex of succinate-cytochrome c reductase (SCR) hosting complex II and complex III, we also observed that diazoxide impaired complex II and its interaction with complex III with no effect on complex III. UV-visible spectral analysis revealed that diazoxide decreased succinate-mediated ferricytochrome b reduction in SCR. In conclusion, our results demonstrated that diazoxide suppressed the in vivo post-ischemic myocardial hyperoxygenation through opening the mitoK(ATP) channel and ubisemiquinone-dependent O(2)(-*) generation via inhibiting mitochondrial complex II-dependent respiration.
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PMID:Opening of the mitoKATP channel and decoupling of mitochondrial complex II and III contribute to the suppression of myocardial reperfusion hyperoxygenation. 1985 35

Storage and tissue handling of surgical tumor specimen have been recognized as critical steps that can potentially affect reproducibility and comparability of molecular endpoints between laboratories. In the preparation of adrenal tumor tissue banking, three different protocols that simulate warm ischemia upon tumor removal (protocol I), thawing and refreezing cycles (protocol II), as well as storage of vital tumor samples (protocol III) were applied. For the first two protocols, samples were subdivided and either snap frozen or treated with a RNA preserving agent (RPA) while in protocol III different storage media were compared. Following these procedures, recovery and integrity of DNA, RNA, and protein by means of pulsed field electrophoresis, long-range PCR, real-time PCR, immunoblot, and immunohistochemistry (protocol I and II) as well as cell viability and steroidogenic capacity (protocol III) were investigated. While DNA integrity was not influenced by different treatment modalities, expression levels of adrenal marker genes were more affected in samples after snap freezing in comparison to RPA pretreatment. Moreover, storage at room temperature before and after freezing could be demonstrated to decrease the relative amount of protein phosphorylation (ERK) and enzymatic activity (succinate cytochrome c reductase) while overall protein levels were not significantly affected. Similarly, morphological or immunohistochemical evaluation was comparable between groups. For primary cell cultures generated after storage of tumor samples similar rates of viability were observable while steroid output varied between the groups. Overall, on the basis of the presented endpoints standardized operational procedures can be defined for a proposed European adrenal tumor biobank.
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PMID:Evaluation of a standardized protocol for processing adrenal tumor samples: preparation for a European adrenal tumor bank. 1988 99

Reactive oxygen/nitrogen species (ROS/RNS) have been increasingly recognized as important mediators and play a number of critical roles in cell injury, metabolism, disease pathology, diagnosis, and clinical treatment. Electron paramagnetic resonance (EPR) spectroscopy enables the spectral information at certain spatial position, and, from the observed line-width and signal intensity, the localized tissue oxygenation, and tissue redox status can be determined. We applied in vivo EPR oximetry and redoximetry technique and implemented its physiological/pathophysiological applications, along with the use of biocompatible lithium pthalocyanine (liPc) and nitroxide redox sensitive probes, on in vivo tissue oxygenation and redox profile of the ischemic and reperfused heart in living animals. We have observed that the hypoxia during myocardial ischemia limited mitochondrial respiration and caused a shift of tissue redox status to a more reduced state. ROS/RNS generated at the beginning of reperfusion not only caused a shift of redox status to a more oxidized state which may contribute to the postischemic myocardial injury, but also a marked suppression of in vivo tissue O(2) consumption in the postischemic heart through modulation of mitochondrial respiration based on alterations in enzyme activity and mRNA expression of NADH dehydrogenase (NADH-DH) and cytochrome c oxidase (CcO). In addition, ischemic preconditioning was found to be able to markedly attenuate postischemic myocardial hyperoxygenation with less ROS/RNS generation and preservation of mitochondrial O(2) metabolism, due to conserved NADH-DH and CcO activities. These studies have demonstrated that EPR oximetry and redoximetry techniques have advanced to a stage that enables in-depth insight in the process of ischemia reperfusion injury.
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PMID:Electron paramagnetic resonance oximetry and redoximetry. 2007 11

The present study has been designed to explore the nitric oxide mechanism in the protective effect of desipramine, venlafaxine and trazodone against I/R induced oxidative stress and mitochondrial dysfunction in mice. Vitamin E was taken as standard antioxidant. Laca mice (25-30 g) were subjected to twice BCCAO occlusion (5 min) at the interval of 10 min, followed by 96 h reperfusion. The drug treatments were started from the day of surgery and continued for the next four days. After 96 h the animals were sacrificed for biochemical (malondialdehyde, nitrite concentration, superoxidedismutase, catalase, redox ratio and GST) and mitochondrial enzyme complex (NADH dehydrogenase, succinate dehydrogenase, MTT assay and cytochrome c oxidase) estimations. Ischemia caused significant oxidative damage and mitochondrial enzyme dysfunction after 96 h of reperfusion as compared to sham operated animals. Antidepressant (desipramine, venlafaxine and trazodone) treatment significantly attenuated oxidative damage and restored mitochondrial enzyme complex activities as compared to control (I/R) group. Further, protective effects of desipramine (15 mg/kg) and/or venlafaxine (5 mg/kg) were attenuated by l-arginine (100 mg/kg) or sildenafil (5 mg/kg) pretreatment. Further, L-NAME (10 mg/kg) or 7-NI (10 mg/kg) pretreatment with desipramine (15 mg/kg) and/or venlafaxine (5 mg/kg) significantly potentiated their protective effect which was significant as compared to their effect alone. The present study highlights the involvement of nitric oxide mechanism in the protective effects of desipramine and venlafaxine against I/R induced oxidative stress and mitochondrial dysfunction in mice.
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PMID:Protective effect of desipramine, venlafaxine and trazodone against experimental animal model of transient global ischemia: possible involvement of NO-cGMP pathway. 2062 74

Changes in the maximal rate of some cerebral enzymatic activities related to energy transduction (lactate dehydrogenase; citrate synthase and malate dehydrogenase; total NADH-cytochrome c reductase and cytochrome oxidase) as well as both glutamate dehydrogenase and acetylcholine esterase were assayed in the purified mitochondrial fraction or in crude synaptosomal fraction from cerebral cortex. The evaluations were performed in rats before and after a postdecapitative normothermic ischemia of 5, 10, 20 and 40 min duration. The ischemic damage resulted in a decrease in the activity of mitochondrial malate dehydrogenase and total NADH-cytochrome c reductase, and of synaptosomal acetylcholine esterase. The biochemical evaluations were performed also after an i.p. pretreatment with vincamine, trimetazidine and suloctidil (50 mg/kg). The drugs induced different changes in enzyme activities as a function of the ischemia duration. These various interferences are discussed with regard to the possible drugs mode of action.
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PMID:The effect of ischemia and pharmacological treatment evaluated on synaptosomes and purified mitochondria from rat cerebral cortex. 2104 37

The purpose of this study was to analyze the nicotinamide adenine dinucleotide phosphate - diaphorase (NADPH-d) activity in the rat jejunum after a mesenteric ischemia/reperfusion injury. Nitric oxide, synthetised from L-arginine by the enzyme nitric oxide synthase, is a nonadrenergic noncholinergic relaxant neurotransmitter of the intestinal smooth muscle. It plays an important role in the process of plasticity after the ischemia/reperfusion injury. Experimental animals were divided in two groups: the control group and the ischemic/reperfusion group, with different period of the reperfusion. The NADPH-d histochemical method has been used as a marker for the nitric oxide synthase. NADPH-d activity has been rapidly decreased in the neurons of both enteric nervous systems in plexuses of the jejunum after 1 h mesenteric ischemia and 1 h reperfusion. Differences were predominantly detected in the myenteric plexus; they were seen in change of the neuronal shape, in the arrangement of neurons and in intensity of their staining. The NADPH-d positivity was absent in the intestinal crypts. After 1 h ischemia and 24 h reperfusion, the NADPH-d activity was gradually increased, but it was lower in comparison with the control group. On the 30th day following the ischemia/reperfusion there were no changes in NADPH-d positivity compared with the control animals. These results indicated that the jejunal ischemia/reperfusion has affected the neurons of the enteric nervous system of adult rats and resulted in the early decrease of NADPH-d positivity 1 h of the reperfusion insult. The gradual increasing of NADPH-d activity in 24 h following the reperfusion could be considered as a result of the plasticity process. On the 30(th) day after the ischemia/reperfusion all histochemical changes were returned to the control levels.
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PMID:NADPH-diaphorase expression in the rat jejunum after intestinal ischemia/reperfusion. 2207 70


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