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: UMLS:C0022116 (ischemia)
91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

On the basis of affirming that acupuncture suppresses neuronal apoptosis following cerebral ischemia, this study investigates the mechanism of acupuncture which modulates the intrinsic factors suppressing and promoting apoptosis. The main results showed that: (1) the symptom of neral defect induced by cerebral ischemia was improved and the area of infarction following cerebra ischemia was reduced after acupuncture treatment; (2) by employing PI and TUNEL staining, the apoptosis neurons were observed following cerebral ischemia, and acupuncture was able to protect against neuronal apoptosis following cerebral ischemia; (3) using a kinetic cadmium-reduction method for the determination of nitric oxide (NO) and an immunohistochemistry method for observation of NOS-immunoactivity in rat brain, it was found that the content of NO in the side of infarction was higher than that of control, and the increase of NO content was positively related to iNOS immunoactivity; acupuncture could inhibit iNOS activity thereby decreasing the NO level; (4) in situ hybridization study revealed that excitotoxicity of glutamate following cerebral ischemia was mediated by NMDAR1mRNA overexpression, that was down-regulated by acupuncture; (5) immunohistochemistry study revealed that the expression of nerve growth factor receptor(trk-A) was induced by acupuncture after cerebral ischemia, which may play a role in antagonizing apoptosis.
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PMID:[A study on the effect and mechanism of acupuncture suppression of neuronal apoptosis following cerebral ischemia]. 1253 26

Exposure to toxic metals and pollutants is a major environmental problem. Cadmium is a metal causing acute hepatic injury but the mechanism of this phenomenon is poorly understood. In the present study, we investigated the mechanism and time-course of cadmium-induced liver injury in rats, with emphasis being placed on apoptosis in parenchymal and nonparenchymal liver cells. Cadmium (3.5 mg/kg body weight) was injected intraperitoneally and the rats were killed 0, 9, 12, 16, 24, 48 and 60 h later. The extent of liver injury was evaluated for necrosis, apoptosis, peliosis, mitoses and inflammatory infiltration in hematoxylin-eosin-stained liver sections, and by assaying serum enzyme activities. The number of cells that died via apoptosis was quantified by TUNEL assay. The identification of nonparenchymal liver cells and activated Kupffer cells was performed histochemically. Liver regeneration was evaluated by assaying the activity of liver thymidine kinase and by the rate of 3H-thymidine incorporation into DNA. Both cadmium-induced necrotic cell death and parenchymal cell apoptosis showed a biphasic elevation at 12 and 48 h and peaked at 48 and 12 h, respectively. Nonparenchymal cell apoptosis peaked at 48 h. Peliosis hepatis, another characteristic form of liver injury, was first observed at 16 h and, at all time points, closely correlated with the apoptotic index of nonparenchymal liver cells, where the lesion was also maximial at 48 h. Kupffer cell activation and neutrophil infiltration were minimal for all time points examined. Based on thymidine kinase activity, liver regeneration was found to discern a classic biphasic peak pattern at 12 and 48 h. It was very interesting to observe that cadmium-induced liver injury did not involve inflammation at any time point. Apoptosis seems to be a major mechanism for the removal of damaged cells, and constitutes the major type of cell death in nonparenchymal liver cells. Apoptosis of nonparenchymal cells is the basis of the pathogenesis of peliosis hepatis. The first peaks of necrosis and parenchymal cell apoptosis seem to evolve as a result of direct cadmium effects whereas the latter ones result from ischemia.
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PMID:Time-course of cadmium-induced acute hepatotoxicity in the rat liver: the role of apoptosis. 1368 93

We reviewed the literature related to the effects of high-dose zinc in arteriosclerosis-induced angina pectoris. Lipid peroxidation and LDL oxidation are believed to be critical for arteriosclerosis, and consequently angina pectoris. Administration of biologically available zinc was a beneficial treatment in a significant percentage of patients with severely symptomatic, inoperable atherosclerotic disease. In these patients, there was no difference in zinc concentration between patients with and without atherosclerosis in whole blood, erythocytes or hair, but there was a major difference between normal aorta and diseased aortas (40.6 ppm zinc in normal aorta vs. 23.2 ppm zinc in atherosclerotic aorta, 40.6 ppm zinc in normal aorta vs. 19.4 ppm zinc in atherosclerotic aneurysm aorta, and no difference between normal and aneurysm aorta), although copper was low in aneurysm aorta. Medication with high-dose zinc sulfate to raise zinc serum concentrations from 95 to 177 microg/dl resulted in objective improvement in 12 of 16 of these patients, including a patient that also had Raynaud's disease. Long term environmental exposure to zinc resulted in a 40% reduction in the incidence of angina of effort compared to people not exposed to environmental zinc (P<0.01) and a 40% reduction in the incidence of probable ischemia in exercise (P<0.001). Lead had no effect while cadmium exposure resulted in more than tripling the incidence of angina of effort (P<0.001). The antioxidative action of zinc prevents oxidation of LDL cholesterol and consequently stops the main mechanism of atherogenesis. Zinc blocks calcium and its several actions on atherogenesis. Increased amounts of cytotoxic cytokines such as TNF-alpha, IL-beta and IL-8, often produced in the elderly, are blocked by high-dose zinc. We hypothesize that higher serum concentrations of LDL cholesterol resulting from administration of 300 mg of zinc per day is caused by a release of low density cholesterol from cardiovascular tissues, beneficially flushing it into the serum where it is readily observed, thus decreasing arteriosclerosis, increasing circulation, terminating angina pectoris and restoring more youthful cardiac function. Although prevention of cholesterol-induced arteriosclerosis by zinc is predicted from findings related to oxidative stress and lipid peroxidation, removal of LDL might be attributable to action of ionic zinc on ICAM inhibition. In stark contrast to current practice, high-dose zinc should be considered as basic in the strategy of prophylaxis and therapy of the atherosclerosis process to terminate angina pectoris and restore youthful cardiac function.
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PMID:High-dose zinc to terminate angina pectoris: a review and hypothesis for action by ICAM inhibition. 1608 66

NADH:ubiquinone oxidoreductase (complex I) from bovine heart mitochondria is a highly complicated, membrane-bound enzyme. It is central to energy transduction, an important source of cellular reactive oxygen species, and its dysfunction is implicated in neurodegenerative and muscular diseases and in aging. Here, we describe the effects of Zn2+ on complex I to define whether complex I may contribute to mediating the pathological effects of zinc in states such as ischemia and to determine how Zn2+ can be used to probe the mechanism of complex I. Zn2+ inhibits complex I more strongly than Mg2+, Ca2+, Ba2+, and Mn2+ to Cu2+ or Cd2+. It does not inhibit NADH oxidation or intramolecular electron transfer, so it probably inhibits either proton transfer to bound quinone or proton translocation. Thus, zinc represents a new class of complex I inhibitor clearly distinct from the many ubiquinone site inhibitors. No evidence for increased superoxide production by zinc-inhibited complex I was detected. Zinc binding to complex I is mechanistically complicated. During catalysis, zinc binds slowly and progressively, but it binds rapidly and tightly to the resting state(s) of the enzyme. Reactivation of the inhibited enzyme upon the addition of EDTA is slow, and inhibition is only partially reversible. The IC50 value for the Zn2+ inhibition of complex I is high (10-50 microm, depending on the enzyme state); therefore, complex I is unlikely to be a major site for zinc inhibition of the electron transport chain. However, the slow response of complex I to a change in Zn2+ concentration may enhance any physiological consequences.
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PMID:The inhibition of mitochondrial complex I (NADH:ubiquinone oxidoreductase) by Zn2+. 1698 Mar 8

Acidification, which occurs in some pathological conditions, such as ischemia and hypoxia often induces neurotoxicity. The activation of acid-sensing ion channels (ASICs), which are highly permeable to calcium, has been considered the main target responsible for calcium overload in ischemic/hypoxic brain. However, the influence of extracellular proton on GABAergic synaptic transmission is not well understood. In the rat (aged 6-12 postnatal days) hippocampal CA3 neurons dissociated with an enzyme-free, mechanical method, we show that raising the extracellular pH (to 8.5) or lowering it (to 6.0) significantly increased or decreased, respectively, the frequency and the amplitude of spontaneous inhibitory postsynaptic currents mediated by gamma-aminobutyric acid A (GABA(A)) receptors. Interestingly, these modifications were not altered by amiloride (100 microM, an antagonist for ASICs), tetrodotoxin (0.5 microM, a sodium channel blocker), cadmium (100 microM, a nonselective blocker for voltage-gated calcium channels), or a medium containing low calcium (0.5 mM). Significantly, changes in extracellular pH biphasically altered the peak amplitude of the currents elicited by exogenous GABA in CA3 neurons dissociated with enzyme. Raising the extracellular pH (to 8.5) or lowering (to 6.5) shifted the concentration-response curves of GABA to the left or right, respectively, without altering the maximal responses. These data suggest that proton alters the apparent affinity of GABA receptors for agonist. Thus, extracellular proton modifies GABAergic synaptic transmission both presynaptically and postsynaptically, and this could be independent of ASICs and voltage-gated calcium channels. Our finding may constitute a new mechanism underlying acidification-induced neurotoxicity.
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PMID:Extracellular proton modulates GABAergic synaptic transmission in rat hippocampal CA3 neurons. 1732 6

Resting neutrophils generate NO, while activation leads to the production of reactive oxygen and nitrogen species. Nowadays cardiovascular pathological conditions such as hypertension, cardiac ischemia, reperfusion and heart failure are associated with inflammation. This project explores the respiratory burst potential and NO generation status in the neutrophils, plasma, aorta, and kidneys from normotensive Wistar and spontaneously hypertensive rats (SHR). Total and protein associated nitrite content was quantitated using Griess reagent following cadmium reduction and mercuric chloride treatment respectively. NO and superoxide generation evaluated by Flowcytometry and peroxynitrite by spectrofluorimetric method. Expression of NOS isoforms was analyzed by RT-PCR. NO generation from SHR neutrophils was significantly augmented in comparison to normotensive counterparts. Neutrophils activated in response to arachidonic acid, PMA, fMLP or E. coli generated more superoxide radicals among SHR, and consequentially peroxynitrite. Expression of iNOS was significantly more in the SHR neutrophils, while that of nNOS remained unaffected. Results suggest that NO generated in SHR is utilized in scavenging superoxide radicals thereby limiting its bioavailability. Thus induction of NOS in neutrophils combined with augmented oxidative stress might influence its association with endothelium and contribute to inflammatory responses under hypertensive condition.
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PMID:Biochemical and molecular evaluation of neutrophil NOS in spontaneously hypertensive rats. 1751 16

This study examined if glutaredoxin-1 (Glrx1), a redox-regulator of thioredoxin superfamily, plays any role in the redox signaling of ischemic myocardium. The hearts were subjected to 30 min of coronary occlusion followed by 24 h of reperfusion. Another group of hearts was rendered tolerant to ischemia (preconditioned, PC) by four cyclic episodes of 5 min ischemia each followed by another 10 min of reperfusion, which was then subjected to 30 min ischemia and 24 h of coronary occlusion. While ischemia/reperfusion had no effect on Glrx1 expression, adaptation to ischemia resulted in the up-regulation of Glrx1 expression, which was inhibited by cadmium, a known inhibitor of Glrx1. CdCl(2) also abolished cardioprotection afforded by PC as evidenced by its ability to partially increase myocardial infarct size without affecting cardiomyocyte apoptosis. The amount of ROS was significantly decreased in the PC heart, which was abolished by CdCl(2). The cardioprotective role of Glrx1was further confirmed with Glrx1 transgenic and knockout mice. The mouse hearts overexpressing Glrx1 exhibited significantly improved post-ischemic ventricular recovery and reduced myocardial infarct size while hearts deficient in Glrx1 exhibited depressed functional recovery and increased infarct size as compared to the wild-type hearts. Furthermore, Glrx1-overexpressing hearts exhibited reduced and Glrx1-deficient hearts exhibited increased ROS production during ischemia and reperfusion. Adapted hearts showed increased Akt phosphorylation that was inhibited by CdCl(2). The amount of Bcl-2 protein expression was not affected by the inhibition of Glrx1. Taken together, the results of this study implicate a role of Glrx1 in cardioprotection and redox signaling of the ischemic myocardium.
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PMID:Role of glutaredoxin-1 in cardioprotection: an insight with Glrx1 transgenic and knockout animals. 2323 Jun 6

This study aimed to underline the interaction between hypoxia-inducible factor-1 (HIF-1) and the inducible nitric oxide synthase (iNOS) gene in vivo and their contribution to the delayed myocardial preconditioning induced by acute intermittent hypoxia (IH) in the rat using chromatin immunoprecipitation and pharmacological inhibition by low-dose cadmium. Langendorff-perfused hearts of Wistar rats exposed to normoxia or IH 24 h earlier were submitted to global ischemia and reperfusion. Effects of iNOS inhibition by aminoguanidine (100 microM) before ischemia or of low-dose injection of cadmium chloride (1 mg/kg) before normoxia or IH were tested. Myocardial HIF-1 and iNOS quantification and in vivo chromatin immunoprecipitation of HIF-1 bound to the iNOS gene promoter were performed. IH-induced delayed cardioprotection resulted in an improvement in coronary flow and functional recovery at reperfusion and a decrease in infarct size. Myocardial HIF-1 activity was increased with resulting targeting of the iNOS gene. Aminoguanidine abolished the cardioprotective effects of IH. Cadmium chloride treatment before IH prevented myocardial HIF-1 activation (72.3 +/- 4.0 vs. 42.1 +/- 9.7 arbitrary units after cadmium chloride; P < 0.05), targeting of the iNOS gene, iNOS expression, and preconditioning (infarct size: 15.9 +/- 5.6 vs. 30.1 +/- 5.4% after cadmium chloride; P < 0.05). This study is the first to demonstrate the interaction of HIF-1 with the myocardial iNOS gene in situ after hypoxic preconditioning. Prevention of HIF-1 activation and iNOS gene targeting by a single low dose of cadmium abolished the delayed cardioprotective effects, bringing insight into the cardiovascular consequences of cadmium exposure.
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PMID:Prevention of HIF-1 activation and iNOS gene targeting by low-dose cadmium results in loss of myocardial hypoxic preconditioning in the rat. 1808 3

The pharmacology of synthetic organoselenium compounds indicates that they can be used as antioxidants, enzyme inhibitors, neuroprotectors, anti-tumor and anti-infectious agents, and immunomodulators. In this review, we focus on the effects of diphenyl diselenide (DPDS) in various biological model organisms. DPDS possesses antioxidant activity, confirmed in several in vitro and in vivo systems, and thus has a protective effect against hepatic, renal and gastric injuries, in addition to its neuroprotective activity. The activity of the compound on the central nervous system has been studied since DPDS has lipophilic characteristics, increasing adenylyl cyclase activity and inhibiting glutamate and MK-801 binding to rat synaptic membranes. Systemic administration facilitates the formation of long-term object recognition memory in mice and has a protective effect against brain ischemia and on reserpine-induced orofacial dyskinesia in rats. On the other hand, DPDS may be toxic, mainly because of its interaction with thiol groups. In the yeast Saccharomyces cerevisiae, the molecule acts as a pro-oxidant by depleting free glutathione. Administration to mice during cadmium intoxication has the opposite effect, reducing oxidative stress in various tissues. DPDS is a potent inhibitor of delta-aminolevulinate dehydratase and chronic exposure to high doses of this compound has central effects on mouse brain, as well as liver and renal toxicity. Genotoxicity of this compound has been assessed in bacteria, haploid and diploid yeast and in a tumor cell line.
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PMID:Pharmacology and toxicology of diphenyl diselenide in several biological models. 1857 57

Myocardial ischemia-reperfusion injury is associated with an imbalance between the formation and the scavenging of reactive oxygen species. In this context, the protective role of the antioxidant metallothionein, a thiol-rich protein that is induced in different organs in response to heavy metals and oxidative conditions, has mainly been investigated in metallothionein-knockout mice or metallothionein-overexpressing mice. The aim of this study was to evaluate whether the administration of cadmium has a protective effect against cardiac ischemia-reperfusion injury and whether this is associated with induction of in vivo cardiac metallothionein. Forty-eight hours after an injection of 0, 1, or 2 mg/kg cadmium, isolated perfused rat hearts were submitted to 30 min of total global ischemia and 30 min of reperfusion. The ischemia-reperfusion sequence was associated with a significant decrease in cardiac metallothionein levels. Pretreatment with cadmium at a dose of 2 mg/kg (i) prevented this decrease and (ii) improved the postischemic recuperation of the coronary flow, the ventricular developed pressure, and therefore, the global postischemic functional recovery. These results showed that pretreatment of rats with 2 mg/kg cadmium induced cardioprotection against ischemia-reperfusion injuries, perhaps through an in vivo metallothionein induction that may be related to a metal activation of antioxidant systems.
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PMID:Effects of cadmium on cardiac metallothionein induction and ischemia-reperfusion injury in rats. 1976 86


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