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)

To clarify the relationship between calcium metabolism and free radical damage during the reperfusion period following ischemia, we investigated the effect of superoxide dismutase (SOD) on changes in cytosolic free calcium, cortical blood flow, and histologic changes following focal cerebral ischemia and reperfusion in 12 cats. Using indo-1, a fluorescent intracellular Ca2+ indicator, we simultaneously measured changes in the Ca2+ signal ratio (400:500 nm), NADH signal (464 nm), and reflectance (340 nm) during ultraviolet excitation (340 nm) directly from the cortex in vivo. The middle cerebral artery (MCA) was occluded for 1 h; only cats in which the EEG amplitude was depressed to less than 10% of control during the occlusion were entered into the study. Starting 2 min prior to release of the occlusion and continuing for 4 min, SOD (10,000 U/kg) was slowly infused in six cats, while in six cats, the vehicle only was infused. During MCA occlusion, the Ca2+ signal ratio increased significantly in both groups with no significant difference between the groups. During reperfusion, the Ca2+ signal ratio remained at a high level in the vehicle-treated group, while in the SOD-treated group, the Ca2+ signal ratio decreased. There was a statistically significant difference between the two groups at 10, 20, and 30 min after reperfusion (p less than 0.01). The histologically damaged area in the SOD-treated group was significantly smaller than that in the vehicle-treated group (p less than 0.01). These data suggest that the histoprotective action of SOD may be due to its ability to attenuate increases in intracellular calcium during the recirculation period following focal cerebral ischemia.
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PMID:Effect of superoxide dismutase on intracellular calcium in stroke. 172 42

Cordialin, the agent extracted from the heart, is known to inhibit hyperoxidation of succinic acid, increasing NADH oxidation speed in suspension of cardiomyocytes in hypoxia. Cordialin presence in oxygenated cells' suspension oxidating succinate, doesn't change oxygen consumption speed. The results received may be a theoretical basis for cordialin utilization in therapy of myocardial diseases, associated with hypoxia and ischemia. Cordialin utilization may be recommended for the treatment of acute myocardial infarction and for prolongation of time-period for thrombolytic therapy, treatment of IMD, angina and other pathological states, in which oxygen transport disturbance to myocardium cells occurs.
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PMID:[Effects of a polypeptide drug on the state of energy metabolism of myocardial cells in hypoxic and ischemic conditions]. 179 41

Ten anesthetized, open-chest dogs were subjected to occlusion of the left anterior descending coronary artery for 15 minutes, followed by reperfusion for 150 minutes. Hemodynamics were recorded and regional myocardial contraction was measured sonometrically. The hearts were then fixed in situ using glutaraldehyde for cytochemical studies. Systolic wall thickening remained unchanged in the non-ischemic myocardium, but was significantly depressed (stunned) in the area of the left anterior descending coronary artery during reperfusion. NADH oxidase and ATPase activities were very weakly present in mitochondria from non-ischemic myocardium. In the ischemic endocardium, irreversibly injured cells had mitochondria which were severely altered and contained no reaction products to the two enzymes. In contrast, high NADH oxidase and ATPase activities were present in mitochondria from the less severely injured cells of the endocardial zone of stunned areas. Since this zone is particularly susceptible to ischemia in dogs, the high mitochondrial NADH oxidase and ATPase activities may be early signs of ischemic damage, reflecting a disturbance in mitochondrial respiratory activity in stunned myocardium.
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PMID:Stunned myocardium has increased mitochondrial NADH oxidase and ATPase activities. 183 16

It is generally thought that the oxidative modification of hemoproteins leads to their inactivation. In the current study, however, a transiently activated form of myoglobin was shown to be formed when the prosthetic heme group became covalently bound to the polypeptide during the reaction of myoglobin with low levels of HOOH. In the presence of an enzymatic metmyoglobin reducing system containing diaphorase and methylene blue with excess NADH, this HOOH-altered myoglobin catalyzed NADH oxidation and oxygen consumption; the overall stoichiometry indicated a two-electron reduction of oxygen to HOOH. This reaction was not catalyzed by iron released from heme, as desferrioxamine had no effect on the activity. Stoichiometric amounts of HOOH were sufficient to produce the activated oxidase state of myoglobin, whereas larger amounts of HOOH lead to heme destruction, iron release, and inactivation of the oxidase activity. The alteration of myoglobin to an enzyme that can form toxic oxygen metabolites may have pathological importance, especially in myocardial injury caused by ischemia and reperfusion, where myoglobin is present in large amounts and HOOH is formed. Furthermore, the oxidase form may be involved in the mechanism of destruction of the heme seen with oxidative treatment of myoglobin.
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PMID:Oxidative modification by low levels of HOOH can transform myoglobin to an oxidase. 187 Nov 23

We studied the efficacy of defibrotide, a prostacyclin-stimulating agent, in preventing ischemia reperfusion injury in Wistar rat heart by using three experimental models: (1) hearts from donors were perfused with the drug (32 mg/kg/hr) during 15, 30, 45, and 60 min of cold ischemia following 5, 10, and 15 min of warm ischemia; (2) hearts from donors treated with the drug were cold-stored for 12 or 24 hr; and (3) procured hearts perfused with the drug were isografted, after 30 or 60 min of warm ischemia, in recipient rats treated daily with defibrotide. Hearts perfused with saline and/or vehicle of the drug were used as controls. At the end of established ischemia times, and after 30 min, and 2, 4, 7 and 14 days from transplantation, hearts were rapidly cooled in liquid nitrogen. ATP, ADP, AMP, cAMP contents, and NAD+/NADH ratios were evaluated in prepared tissue extracts. Cardiac ATP and ADP levels and NAD+/NADH ratios were significantly higher in defibrotide-treated organs than in controls. Isografted defibrotide-treated hearts were also significantly preserved, with respect to controls, from the loss of ATP levels until rejection occurred. Our results demonstrate the protective activity of the drug against the myocardial metabolic damage due to ischemia-reperfusion.
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PMID:Protection of rat heart from damage due to ischemia-reperfusion during procurement and grafting by defibrotide. 192 39

Intracellular pH (pHi) and cytoplasmic and mitochondrial oxidation-reduction (redox) states of cerebral tissue were examined in relation to perturbations of glycolytic and tricarboxylic acid cycle intermediates and of high-energy phosphate reserves during hypoxia-ischemia and the early recovery period in the immature rat. Seven-day postnatal rats underwent unilateral common carotid artery ligation and exposure to 8% O2 for 3 h, after which they were quick frozen in liquid N2 at the terminus of hypoxia-ischemia and at 10, 30, 60, and 240 min of recovery for enzymatic fluorometric analysis of cerebral metabolites. During hypoxia-ischemia, concentrations of glucose and alpha-ketoglutarate in the cerebral hemisphere ipsilateral to the carotid artery occlusion were depleted to 10 and 70% of control, respectively; pyruvate was unchanged. During recovery, glucose, pyruvate, and alpha-ketoglutarate increased above their respective control values. Calculated pHi decreased from 7.0 (control) to 6.6 during hypoxia-ischemia and normalized by 10 min of recovery. The cytoplasmic NAD+/NADH ratio decreased (increased reduction) to 50% of control during hypoxia-ischemia and remained in the reduced state throughout 4 h of recovery. Paradoxically, mitochondrial NAD+/NADH was oxidized at the terminus of hypoxia-ischemia. The mitochondrial oxidation which developed during hypoxia-ischemia presumably results from a limitation of cellular substrate (glucose) supply, which in turn leads to a depletion of high-energy phosphate reserves, culminating in brain damage.
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PMID:Cerebral oxidative metabolism and redox state during hypoxia-ischemia and early recovery in immature rats. 192 92

After ligation of the left coronary artery, porcine cardiac mitochondria were isolated by homogenizing the tissue and treating the myofibrillar pellet with nagarse. When compared with unligated controls, the ischemic myocardium showed decreases in phosphocreatine (to 41%), ATP (to 56%) and in the mitochondrial respiratory control index (to 69% and 78% as measured with glutamate and succinate respectively). No changes were found in the corresponding P/O ratios. Similar results were obtained upon separation of the mitochondria into two main fractions by a density gradient technique, though only one of these fractions showed a fall in succinate-supported respiration. The results suggest that ischemia decreases the NADH-dehydrogenase activity of cardiac mitochondria.
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PMID:Changes in myocardial mitochondrial respiration after ligation of the coronary artery in pigs. 198 32

Transient focal ischemia was produced in rat brain using simultaneous, reversible occlusion of the middle cerebral artery (MCA) and both carotid arteries. NADH tissue fluorescence and regional levels of ATP and lactate were measured after occlusion for 1 or 2.5 h and after reperfusion for 1 or 24 h following a 2.5-h insult. Occlusion for 1 or 2.5 h caused a marked but microheterogenous increase in NADH fluorescence, which was restricted to the MCA territory of the ipsilateral cortex. In this ischemic core, tissue levels of ATP were nearly depleted, while lactate accumulated to 10-13 mmol/kg. Metabolic alterations were less pronounced in regions adjacent to the ischemic core; however, one border region experienced a progressive increase in lactate between 1 and 2.5 h. NADH fluorescence and metabolite levels were not significantly altered in subcortical structures. In animals reperfused after a 2.5-h insult, NADH fluorescence diminished in the ischemic core to abnormally low levels, ATP was restored only to 37-50% of control, and lactate remained elevated. By 24 h, histologic infarction was evident in the regions with metabolic impairment. These results indicate that focal depletion of energy metabolites for 2.5 h caused irreversible impairment of energy metabolism and focal infarction even though lactate accumulation was moderate.
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PMID:NADH fluorescence and regional energy metabolites during focal ischemia and reperfusion of rat brain. 201 54

In isolated adult rat myocytes, we tested the hypothesis that metabolic inhibition and simulated ischemia regulate the NADH/NAD+ redox couple with concomitant impairment of energy-dependent process, including contraction and maintenance of high-energy phosphate stores. We developed a method to examine the relationship among the redox couple, ATP content, and contractile performance in single cells under several conditions analogous to myocardial ischemia, with and without reperfusion. Myocytes were paced at 1 Hz while cell contraction and NADH fluorescence were determined simultaneously for single cells at 37 degrees C. Cells were exposed to cyanide and 2-deoxy-D-glucose (metabolic inhibition) or to metabolic inhibition plus 12 mM KCl and 20 mM lactate at pH 6.5 (simulated ischemia). Pyridine nucleotide fluorescence signals from single cells studied in this fashion could be modulated by metabolic inhibitors in a manner similar to that classically described for isolated mitochondria. Metabolic inhibition or simulated ischemia quickly produced maximal reduction of NAD+ to NADH. When cells were exposed to simulated ischemia for 10 min, then superfused with glucose-containing control buffer, 28% of cells exposed to conditions of simulated ischemia developed hypercontracture on reperfusion. Hypercontracture developed despite mitochondrial electron transport being reestablished. When myocyte suspensions in a cuvette were studied spectrofluorimetrically, the pyridine nucleotide fluorescence response to metabolic inhibitors was similar to that for a single cell. This permitted correlation of ATP determinations on cells in suspension with contractile and fluorescence measurements from single myocytes. In the absence of glycolysis there is correspondence among loss of electron transport, decline in high-energy phosphate concentration, and decline in contraction. Irreversible disruption of the electron transport process does not appear to be an early event in ischemic injury.
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PMID:NADH measurements in adult rat myocytes during simulated ischemia. 205 13

Ischemia and reperfusion causes severe mitochondrial damage, including swelling and deposits of hydroxyapatite crystals in the mitochondrial matrix. These crystals are indicative of a massive influx of Ca2+ into the mitochondrial matrix occurring during reoxygenation. We have observed that mitochondria isolated from rat hearts after 90 minutes of anoxia followed by reoxygenation, show a specific inhibition in the electron transport chain between NADH dehydrogenase and ubiquinone in addition to becoming uncoupled (unable to generate ATP). This inhibition is associated with an increased H2O2 formation at the NADH dehydrogenase level in the presence of NADH dependent substrates. Control rat mitochondria exposed for 15 minutes to high Ca2+ (200 nmol/mg protein) also become uncoupled and electron transport inhibited between NADH dehydrogenase and ubiquinone, a lesion similar to that observed in post-ischemic mitochondria. This Ca(2+)-dependent effect is time dependent and may be partially prevented by albumin, suggesting that it may be due to phospholipase A2 activation, releasing fatty acids, leading to both inhibition of electron transport and uncoupling. Addition of arachidonic or linoleic acids to control rat heart mitochondria, inhibits electron transport between Complex I and III. These results are consistent with the following hypothesis: during ischemia, the intracellular energy content drops severely, affecting the cytoplasic concentration of ions such as Na+ and Ca2+. Upon reoxygenation, the mitochondrion is the only organelle capable of eliminating the excess cytoplasmic Ca2+ through an electrogenic process requiring oxygen (the low ATP concentration makes other ATP-dependent Ca2+ transport systems non-operational).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Mitochondrial generation of oxygen radicals during reoxygenation of ischemic tissues. 206 Aug 40


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