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)

It has been shown that Stat3 is induced following transient cerebral ischemia in rat. However there is no evidence that cerebral ischemia stimulates the expression of phosphorylated-Stat3 (p-Stat3), which can activate cytokine-mediated signal transduction from the membrane to the nucleus. In the present study, we investigated the changes in p-Stat3 expression following middle cerebral artery occlusion in mice. Western blot analysis revealed a significant increase in the p-Stat3 protein in the peripheral part of the ischemic area, starting from 6 h after ischemia. p-Stat3 immunoreactivity was detected only in neurons, but not in astrocytes or microglia, and p-Stat3-positive neurons were increased in number in the peripheral part of the ischemic area at 24 h after ischemia. Double staining with aTdT-mediated biotinylated UTP nick end labeling (TUNEL) kit and the p-Stat3 antibody indicated that p-Stat3-positive neurons were also TUNEL-positive. Subsequent immuno-electron microscopic observations showed that p-Stat3-positive neurons were at different stages of degeneration. The present findings suggest that the increased expression of p-Stat3 after cerebral ischemia could play a crucial role in ischemia-induced neuron death.
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PMID:Induction of phosphorylated-Stat3 following focal cerebral ischemia in mice. 1132 8

The blood clearance of Tc99m MIBI is rapid and biexponential, with an initial fast phase followed by a slow phase. The fundamental myocellular uptake mechanism involves passive distribution across plasma and mitochondrial membranes, and at equilibrium, sestamibi is sequestered within the mitochondria by the larger negative mitochondrial transmembrane potential. Reverse distribution into blood stream is stopped by the high membrane potential of the cardiac cells. Scintigraphic changes followed by the metabolic abnormalities in patients after acute carbon monoxide poisoning can be necrosis or only the transitory ischemia. It seems to detect accurately the extension of the early necrosis (unreversible) of the myocardium. Amiscan kit for the preparation of Tc99m-glucarate is being developed as a radiopharmaceutical diagnostic agent for the imaging of and diagnosis of acute myocardial necrosis. Cellular and subcellular uptake studies have shown that Tc99m-glucarate localizes in necrotic tissues binding primarily to the nucleoprotein sub-fractions and to a lesser extent to the DNA fractions. Glucarate is taken up rapidly by necrotic myocardium and cleared relatively rapidly from the circulation resulting in early, hight target-to-background ratios. In studies of Amiscan in patients with acute myocardial infarction, sensitivity was found to be 100% when Amiscan is administered within 9 hours of the onset of chest pain. In our preliminary study the scintigraphic scans using Tc99m-glucarate were performed in 10 patients after acute carbon monoxide poisoning. The study can confirm that some patients during acute CO poisoning have typical myocardial necrosis, but part of them have hibernating and/or stunned myocardium.
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PMID:New possibilities in scintigraphy detection of carbon monoxide cardiotoxicity. 1145 Mar 31

INTRODUCTION: Heart transplantation is often accompanied by multiple functional alterations, especially in reperfusion period. These are probably related to the reactive oxygen species (ROS) formation catalyzed by transition metals such as iron and copper, and thus the preservation time of the donor hearts is limited. Metabolic protection of the heart grafts is a permanent objective of numerous experiments. Recently, an iron chelator deferoxamine (DFX) was proposed as antioxidant agent for storage solutions in heart grafts. Oxidative stress is also known to mediate the apoptotic cell death in different tissues during ischemia-reperfusion. METHODS: The aim of this study was to evaluate a possible role of DFX in prevention of apoptosis using in vitro model of isolated working rat heart and cold cardioplegia. Two groups of rats were evaluated: (a) group 'DFX 50 &mgr;M' (n=8) and (b) group 'controls' (n=8). Isolated rat hearts were perfused by Krebs-Henseleit buffer (KHB) for 30 min, arrested by cardioplegic solution and stored for 4 h in B21 solution at 4 degrees C. Then, the hearts were reperfused by KHB for 45 min. DFX was added to the cardioplegic and storage solutions and in KHB in reperfusion. Basic functional parameters were evaluated: coronary, aortic, cardiac outputs and heart rate. At the end of reperfusion period a tissue samples were taken from left ventricle and in situ detection of apoptotic cells was performed using an ApopTag kit. RESULTS: DFX significantly reduced the occurrence of apoptotic cells in myocardium (*P<0.05). Hearts treated by 50 &mgr;M of DFX showed also a better recovery of the cardiac output (***P<0.001). The presence of DFX in KHB, cardioplegic and storage solution reduced also the incidence of postischemic arrhythmias and fibrillation's but without statistical significance. CONCLUSIONS: Our results give evidence of the protective potential of DFX during cold ischemia and reperfusion, presumably due to its antioxidant properties. The significant decrease of apoptosis in hearts treated by DFX could be considered as an existence of close link between oxidative stress and apoptotic death promotion in ischemia-reperfusion injury.
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PMID:Prevention of apoptosis by deferoxamine during 4 hours of cold cardioplegia and reperfusion: in vitro study of isolated working rat heart model. 1238 62

INTRODUCTION: Melatonin (MEL), a pineal hormone, is well known as a potent antioxidant in a variety of ischemia-reperfusion models. Recent studies have assumed a pivotal role of reactive oxygen species (ROS) in the development of apoptosis. There are few pieces of information concerning a possible protective role of MEL against apoptosis in ischemia-reperfusion injury of myocardium. METHODS: We conducted an in vitro experiment: (1) to study the effect of MEL in the model of isolated and perfused working rat heart; (2) to evaluate the antioxidant capacity of MEL by a simple fluorescence test; and (3) to analyze the extent of apoptosis inhibition by MEL. Four groups of male Wistar rat were used: (a) group 'MEL 50 muM' (n=8); (b) group 'ischemia 30 min' (n=8); (c) group 'controls' (n=8); and (d) group 'controls+MEL 50 muM' (n=8). The perfusion medium was an oxygenated Krebs-Henseleit buffer (KHB). Hearts in groups (a) and (b) underwent 30 min of global normothermic ischemia and 45 min of reperfusion; 3 min before ischemia the hearts of group (a) received KHB with MEL 50 muM (and MEL 50 muM was also present in KHB solution during reperfusion). Hearts of group (c) were only perfused by KHB, and hearts of group (d) perfused by KHB+MEL 50 muM throughout the experiment. Registered were basic hemodynamic parameters: coronary, aortic, cardiac output and heart rate. At the end of each experiment, a left ventricle samples were taken for in situ detection of apoptosis using a TUNEL in-situ detection kit (POD) and quantitative analysis was performed. Malonedialdehyde concentrations were evaluated from heart homogenate to determine the severity of oxidative damage. To study the antioxidant capacity of MEL, a fluorescence test with allophycocyanin as an indicator was performed. A peroxyl radical generator, 2,2'-azobis(2-amidinopropan)-4-hydrochloride (AAPH) was used, and the antioxidant effect of MEL was expressed in oxygen-radical absorbing capacity (ORAC) units. RESULTS: Treatment by MEL resulted in a significant improvement of hemodynamic parameters and reduction of postischemic arrhythmias during reperfusion. All hearts in group 'ischemia 30 min' developed fatal ventricular fibrillations. MEL significantly reduced the incidence of apoptotic cells (14+/-4.3%; **P<0.01) vs. group 'ischemia 30 min' (58+/-2.1%). No apoptotic cells were detected in both control groups (c) and (d). In the fluorescence test, MEL exhibited a significant dose-dependent protective effect against peroxyl radical; MEL also reduced significantly the level of lipoperoxidation (MDA; *P<0.05). Analysis of hemodynamic parameters in both control groups (c) and (d) did not show any significant differences; the presence of MEL 50 muM in KHB solution did not have any important influence on cardiac performance in this type of experiment. CONCLUSION: We confirmed the previously reported beneficial effects of MEL against ischemia-reperfusion injury, presumably via its antioxidant properties. A significant suppression of apoptosis and the peroxyl radical scavenging properties of MEL in our study could contribute to the hypothesis of a close link between oxidative stress and apoptosis promotion.
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PMID:Melatonin protects against ischemia-reperfusion injury and inhibits apoptosis in isolated working rat heart. 1456 33

Erythropoietin (Epo) has been shown to act as a neurotrophic and neuroprotective factor via binding to its receptor (EpoR) which is activated in adult brains following hypoxia and ischemia. However, no evidence suggests that cerebral ischemia can activate EpoR in the neonatal brain. In the present study, the changes in EpoR expression were investigated using a modified model of permanent focal cerebral ischemia (FCI) in 7-day-old rat pups. Western blot analysis with an anti-rabbit EpoR antibody revealed a significant increase in the EpoR protein in the ischemic areas, starting from 6 to 12 h after FCI. Moreover, many EpoR-positive cells were detected in the ischemic areas from 12 h after FCI, and the positive cells were identified as neurons and microglia/macrophage but not astrocytes 24 h after FCI. Additionally, double staining with a red in situ apoptosis detection kit and the EpoR antibody indicated that EpoR-positive cells were in apoptotic cell death in the ischemic area. Therefore, these results suggest that EpoR is activated in the ischemic areas of neonatal rats and plays an important role in brain injury during development.
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PMID:Permanent focal cerebral ischemia activates erythropoietin receptor in the neonatal rat brain. 1473 57

The purpose of this study was to validate the Albumin Cobalt Binding (ACB) assay at the Seattle Veterans Affairs (VA) Hospital to determine if it would provide an earlier rule-out of acute coronary syndrome (ACS) in patients, compared to current use of cardiac injury markers. This study compares the distribution of ischemia modified albumin (IMA) values of our patient population to those provided by the kit manufacturer. IMA values were determined photometrically on a Roche Modular Analytical System on 200 subjects: 69 subjects not experiencing chest pain (normals), 78 subjects presenting to the emergency room (ER) with chest pain whose initial and subsequent troponin results were negative (non-converters), and 53 subjects presenting to the ER with chest pain whose initial troponin result was negative but subsequent troponin results were positive (converters). Based on the relationships between IMA values in the initial samples from the non-converters and converters, we constructed a ROC curve to identify an optimum IMA rule-out value. The IMA values (mean+/-SD) for the normals, non-converters, and converters were 89+/-7.1, 100+/-13.9, and 126+/-14.1 U/ml, respectively, and each mean was statistically different from the means of the other groups. The ROC curve comparing converters and non-converters showed an area of 0.89 (p <0.001) compared to the line of identity. An IMA cut-off of 97 U/ml gives a 98% sensitivity and 45% specificity and may be the best decision point to differentiate between these groups in our population. Nine of 78 non-converters were classified as having unstable angina. In conclusion, the ACB assay has a strong negative predictive value and sensitivity in our population for predicting the troponin results at 6 to 24 hr post-presentation. Because ACB results may be facility- and instrument-dependent, each facility should conduct an independent ROC analysis to determine the optimal IMA rule-out level. The ACB assay, when used in conjunction with cardiac injury markers and assessment of unstable angina, holds promise in reducing inappropriate low-risk hospital admissions and improving the clinical management of patients with chest pain.
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PMID:Albumin cobalt binding assay to rule out acute coronary syndrome. 1583 Jul 11

Oxidative stress may cause apoptosis of cardiomyocytes in ischemia-reperfused myocardium, and heat shock pretreatment is thought to be protective against ischemic injury when cardiac myocytes are subjected to ischemia or simulated ischemia. However, the detailed mechanisms responsible for the protective effect of heat shock pretreatment are currently unclear. The aim of this study was to determine whether heat shock pretreatment exerts a protective effect against hydrogen peroxide(H2O2)-induced apoptotic cell death in neonatal rat cardiomyocytes and C2C12 myogenic cells and whether such protection is associated with decreased release of second mitochondria-derived activator of caspase-direct IAP binding protein with low pl (where IAP is inhibitor of apoptosis protein) (Smac/DIABLO) from mitochondria and the activation of caspase-9 and caspase-3. After heat shock pretreatment (42 +/- 0.3 degrees C for 1 hour, recovery for 12 hours), cardiomyocytes and C2C12 myogenic cells were exposed to H2O2 (0.5 mmol/L) for 6, 12, 24, and 36 hours. Apoptosis was evaluated by Hoechst 33258 staining and DNA laddering. Caspase-9 and caspase-3 activities were assayed by caspase colorimetric assay kit and Western analysis. Inducible heat shock proteins (Hsp) were detected using Western analysis. The release of Smac/DIABLO from mitochondria to cytoplasm was observed by Western blot and indirect immunofluorescence analysis. (1) H2O2 (0.5 mmol/L) exposure induced apoptosis in neonatal rat cardiomyocytes and C2C12 myogenic cells, with a marked release of Smac/DIABLO from mitochondria into cytoplasm and activation of caspase-9 and caspase-3, (2) heat shock pretreatment induced expression of Hsp70, Hsp90, and alphaB-crystallin and inhibited H2O2-mediated Smac/DIABLO release from mitochondria, the activation of caspase-9, caspase-3, and subsequent apoptosis. H2O2 can induce the release of Smac/DIABLO from mitochondria and apoptosis in cardiomyocytes and C2C12 myogenic cells. Heat shock pretreatment protects the cells against H2O2-induced apoptosis, and its mechanism appears to involve the inhibition of Smac release from mitochondria.
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PMID:Heat shock pretreatment inhibited the release of Smac/DIABLO from mitochondria and apoptosis induced by hydrogen peroxide in cardiomyocytes and C2C12 myogenic cells. 1618 70

This study was designed to evaluate the effect of recombinant human erythropoietin (rhEPO), insulin-like growth factor-1 (rhIGF-1) and epidermal growth factor (rhEGF) on ischemia-induced hair cell loss in an organotypic cochlea culture. The apical, middle and basal parts of the organs of Corti (newborn rat, postnatal days 3-5) were exposed to ischemia (3.5 h) in glucose-free artificial perilymph (pO2 10-20 mmHg) with or without growth factors. Controls were exposed to normoxia. Twenty-four hours after the onset of ischemia, the cultures were stained using tetramethyl rhodamine isothiocyanate (TRITC) phalloidin (hair cells), propidium iodide (membrane integrity) and apoptosis detection kit (DNA-fragmentation). Ischemia (3.5 h) induced a hair cell loss of 20 and 40% in the middle and basal cochlear parts, respectively, and an increase of the numbers of PI-stained and DNA-fragmented nuclei (controls 0-1, ischemia 4-7 nuclei/100 microm). The basal part was more affected than the apical one. rhEPO and rhIGF-1 significantly attenuated the ischemia-induced hair cell loss by reducing processes involved in apoptosis and necrosis. rhEPO has been in clinical use for more than a decade and found to be well tolerated. Therefore, rhEPO could be an effective drug for the prevention of hearing loss via a hair cell protective mechanism.
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PMID:Recombinant human erythropoietin prevents ischemia-induced apoptosis and necrosis in explant cultures of the rat organ of Corti. 1633 12

The effects of SB203580 (SB) with different concentrations at different time points on renal function, apoptosis, P38MAPK activity and the expression, as well as the P38MAPK substrates in renal ischemia/reperfusion injury were investigated. Forty-nine rats were divided into 7 groups at random (n = 7 in each group) according to the durations of ischemia/reperfusion injury and the time of medication. Based on the orthogonal Latin side, the rats were injected, by caudal vein, with the same volume but different dosages of SB. BUN and Scr were determined. The apoptosis was detected with TUNEL kit. The protein was assayed qualitatively and semi-quantitatively by Western blot. The results showed that SB could significantly reduce the increased Scr and BUN, the apoptosis of renal tubular epithelia and the activation of P38MAPK all caused by renal ischemia/ reperfusion injury in a dose-dependent manner (P < 0.05). And the effect was most predominant when SB was given 3 h before renal ischemia. This suggested that SB could significantly alleviate renal ischemia/reperfusion injury. Administration of SB 3 h before ischemia at the concentration of 5 micromol/L could obtain an optimal effect.
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PMID:Influence of SB203580 on cell apoptosis and P38MAPK in renal ischemia/reperfusion injury. 1671 Oct 7

The role of calcium channels blockers in ischemic condition has been well documented. The PhTx3 neurotoxic fraction of the spider Phoneutria nigriventer venom is a broad-spectrum calcium channel blocker that inhibits glutamate release, calcium uptake and also glutamate uptake in synaptosomes. In the present study we describe the effect of PhTx3 (1.0 microg/mL), omega-conotoxin GVIA (1.0 micromol/L) and omega-conotoxin MVIIC (100 nmol/L) on neuroprotection of hippocampal slices and SN56 cells subjected to ischemia by oxygen deprivation and low glucose insult (ODLG). After the insult, cell viability in the slices and SN56 cells was assessed by confocal microscopy and epifluorescence, using live/dead kit containing calcein-AM and ethidium homodimer. Confocal images of CA1 region of the rat hippocampal slices subjected to ischemia insult and treated with omega-conotoxin GVIA, omega-conotoxin MVIIC and PhTx3 showed a percentage of dead cells of 68%, 54% and 18%, respectively. The SN56 cells subjected to ischemia were almost completely protected from damage by PhTx3 while with omega-conotoxin GVIA or omega-conotoxin MVIIC the cell protection was only partial. Thus, PhTx3 provided robust ischemic neuroprotection showing potential as a novel class of agents that targets multiple components and exerts neuroprotection in in vitro model of brain ischemia.
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PMID:Neuroprotective effect on brain injury by neurotoxins from the spider Phoneutria nigriventer. 1675 53


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