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)

The effect of 1.5 to 2.5 h tourniquet ischemia on energy metabolism of the quadriceps muscle was studied using percutaneous needle biopsy technique in sixteen patients operated on for an inveterated knee injury. During occlusion there was a moderate decrease in ATP with an increase in ADP and AMP. This change resulted in a decreased energy charge potential. At the same time phosphorylcreatine (PC) decreased markedly while creatine (Cr) increased giving a constant total creatine (TCr). An accumulation of lactate during occlusion with values up to 80 mmol/kg d.m. (dry muscle) was seen. A 15% reduction in glycogen was calculated. After release of the tourniquet the active phosphate concentration and the energy charge potential returned to basal levels within 5 min and most of the metabolites in the glycolytic sequence were also normalized. Muscle lactate content was normal after 30 min of intact circulation. The results suggest that longterm tourniquet ischemia induces marked changes in energy metabolism in skeletal muscle, but that the changes are rapidly and completely reversible with restoration of blood flow.
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PMID:The effect of long-term arterial occlusion on energy metabolism of the human quadriceps muscle. 52 75

The present study, which concerns the rate of changes in the cerebral cortex concentrations of phosphocreatine (PCr), ATP, ADP, AMP, lactate and pyruvate during complete ischemia, had the objective of finding out whether or not phenobarbital retards depletion of tissue energy reserves during ischemia. Ischemia was induced for periods of 10 s to 10 min in animals maintained on 70% N2O or given 150 mg.kg-1 of phenobarbital. The results showed that the barbiturate anaesthesia delayed utilization of ATP during the first 2 min. However, after 5 min of ischemia PCr and ATP concentrations, as well as the calculated adenylate energy charge, were identical in animals anaesthetized with nitrous oxide and phenobarbital. Thus, phenobarbital induces a very moderate delay in the depletion of cerebral energy reserves that occurs during complete ischemia. The results obtained after 5-20 s of ischemia allowed calculation of energy (approximately P) utilization according to Lowry et al. (1964). The closed system method gave values for approximately P utilization which were not far from those obtained by CMRo2 measurements. However, with normal values for metabolic rate (70% N2O) valid estimates are obtained only with very short ischemic periods (5-10 s) and, with such short periods, the oxygen content of the tissue may introduce an error.
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PMID:Influence of phenobarbital on changes in the metabolites of the energy reserve of the cerebral cortex following complete ischemia. 71 81

In the atrioventricular system (AVS) consisting of the compact node, the penetrating bundle and the branching bundles of about 250 bovine hearts there were made several studies: 1. In quickly removed and fixed specimens (distal AV-node, penetrating bundle) determination of a metabolic state with respect to glycogen, glucose, lactate, ATP, ADP, AMP, creatinephosphate, total creatine, gluc-6-phosphate, fructose-6-phosphate, fructose-1,6-diphosphate, dihydroxyacetonphosphate and pyruvate. 2. Determination of glycogen contents and glygolytic activity in AVS and its parts for ischemic times up to three hours. 3. The determination of metabolic contents in samples of connective tissue in atrium and ventricle of bovine hearts. The AV-nodes are poor in glycogen comparable with glycogen content of central nervous system and other ganglia. Penetrating bundles of Hiss and branching bundle belong after liver to the glycogen richest parenchyma of animal tissues. Even after ischemia of 3 h only a part of glycogen was recovered as lactate. The greater part of glycogen must be considered as a structural element of Hiss bundle and branching bundles of the ventricles.
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PMID:[Contents of glycogen, glycolytic activity and contents of metabolites in the atrioventricular system of bovine hearts (author's transl)]. 73 46

The behaviour of fuels (glycogen, glucose), of glycolytic pathway intermediates (glucose-6-phosphate, pyruvate) and end-product (lactate), as well as the pool of labile phosphates (ATP, ADP, AMP, creatine phosphate) and the energy charge of the brain were studied in the motor area of the cerebral cortex of beagle dogs. These parameters were evaluated both after various hypoxic conditions (hypoxic hypoxia, hypoxia plus complete or incomplete ischemia) and after 3, 15 or 30 min of post-hypoxic recovery and recirculation. The effect of some drugs (papaverine, UDP-glucose, (-)eburnamonine, suloctidil) following intracarotid perfusion has been evaluated in the various quoted experimental conditions. The tested drugs proved unable to improve the deranged brain metabolism under all the hypoxic conditions. On the contrary, an activating effect of suloctidil and (-)eburnamonine could be observed during the recovery after both hypoxia and hypoxia plus complete ischemia, papaverine being ineffective and UDP-glucose increasing the glycogen synthesis. The drugs proved unable to induce a restitution of the altered brain metabolism after hypoxia plus incomplete ischemia.
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PMID:Drug action on cerebral energy state during and after various hypoxic conditions. 74 71

The metabolic consequences of low-temperature kidney preservation were investigated. A comparison was made between kidneys which were immediately preserved and kidneys which had been ischemic for 1 hour. Two types of preservation techniques were used: (1) continuous perfusion with oxygenated plasma as described by Belzer and (2) a single flush with potassium-containing perfusate as suggested by Collins. Slices of renal cortex were removed at varying times during preservation and analyzed for a variety of metabolic intermediates. ATP levels were markedly reduced from normal. The Belzer technique was associated with higher ATP levels and ischemia lowered the ATP level. Kidneys perfused by the Belzer technique had lower ADP levels than those by the Collins method. Preservation caused marked elevation of tissue lactate, irrespective of ischemia or the technique used. We conclude that low temperature kidney preservation has profound effects on cellular metabolism. Therefore, the measurement of metabolic intermediates may provide a rational approach to the prediction of organ survival.
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PMID:Metabolic consequences of low-temperature kidney preservation. 79 69

The effects of occlusion of the left anterior descending coronary artery on a variety of metabolic parameters was examined in both infarcted and noninfarcted areas of the dog heart. These included mitochondrial performance, glycolysis, in vitro contractility, and regional myocardial blood flow. Measurements were made at 1 and 3 h after onset of ischemia. Regional coronary blood flow was measured in infarcted, noninfarcted and borderline regions using radioactive microspheres. Blood flow through the ischemic area was reduced by an average of 69% after 1 h of ischemia, and 75% after 3 h. After 3 h the subendocardium of the borderline region also revealed a significantly reduced blood flow. Mitochondria isolated from the ischemic region of the heart exhibited a substantial decrease in the rate of respiration (QO2), and minor reductions in the coupling between oxidative phosphorylation and electron transport (RCI), and in the amount of ADP phosphorylated per oxygen reduced (ADP:O ratio). Levels of hexose monophosphates were elevated 1 and 3 h after ischemia was initiated. At the same time, the concentration of fructose-1,6-diphosphate declined markedly, reflecting inhibition of glycolysis at the phosphofructokinase level. Concentrations of the adenosine phosphate moieties, as well as creatine phosphate, were reduced, while levels of free fatty acids were elevated in ischemic tissue. The in vitro contractility of glycerinated ischemic muscle fibers was also depressed. Significant changes were found in maximal tension development (P0), maximal rate of tension development (dp/dtmax), time to peak tension (t0), and shortening velocity at zero load (Vmax).
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PMID:Regional blood flow, contractility and metabolism in early myocardial infarction. 87 51

To determine whether platelets play a part in the pathogenesis of transient cerebrovascular ischemia, we studied 22 patients with transient ischemia, 18 control patients and 38 normal subjects. Platelet aggregation and [14C]-serotonin release by ADP, epinephrine and collagen were normal in all patients, as were plasma coagulation assays, except for shortened partial thromboplastin times in the patients with transient ischemia. Platelet coagulant activities concerned with initiation and early stages of intrinsic coagulation were increased two to three times in 12 patients with transient ischemic attacks with normal serum lipids and normal in the 10 others with Type IV hyperlipoproteinemia. These results indicate an association between platelet coagulant hyperactivity and transient ischemic attacks in a group of patients with normal serum lipids.
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PMID:Platelet coagulant activities and serum lipids in transient cerebral ischemia. 95 87

This study determines the effect of ischemia and reperfusion on energy-linked Ca2+ uptake by myocardial mitochondria. The left anterior descending coronary artery was occluded in 14 mature pigs for 2 hr. In seven animals the ligature was released and the ischemic zone reperfused for 2 additional hours. After sacrifice, mitochondrial function was measured in normal and reperfused or ischemic areas of the left ventricle, using a polarographic method. Mitochondria were prepared without EDTA by standard procedures and Ca2+ uptake measured by 45Ca2+ isotope tracer. Uptake of Ca2+ by mitochondria derived from ischemic myocardium is markedly impaired with or without phosphate. Reperfusion may accentuate this impairment. The presence of exogenous Ca2+ inhibits the ability of ischemic or reperfused mitochondria to phosphorylate ADP.
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PMID:Alteration in calcium metabolism in mitochondria isolated from ischemic and reperfused myocardium. 103 50

The tolerance of ischemia in normal and less perfused myocard during an ischemic and cardioplegic heart standstill was investigated. A decrease of ATP and ADP and an increase of the lactate, pyruvate and AMP was established during an ischemia of 20 minutes. The less perfused hearts gave considerably worse results regarding the energy transformation than normal hearts. In less perfused hearts the energy reserve of myocardial metabolism showed a considerably better behaviour during a cardioplegic heart standstill of 45 minutes than an ischemic one of 20 minutes. During the recuperation period this trend was emphasised.
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PMID:[The effect of ischemic and cardioplegic heart standstill on the myocard metabolism in normal and less perfused heart (author's transl)]. 108 Jun 11

An in situ working swine heart preparation is described in which total coronary perfusion was controlled. At normal rates of coronary flow, oxygen, glucose, and fatty acid utilization were stable for at least a 60-min perfusion period. With a 50% reduction in coronary flow, oxygen and glucose consumption were reduced during 30 min of perfusion and fatty acid extraction was lower at the end of 30 min. Glycogen utilization was increased, but tissue levels of creatine phosphate, ATP, and lactate were similar to those in hearts receiving normal flow. With a 60% reduction in coronary flow, uptake of oxygen, glucose, and fatty acids were further decreased. Tissue levels of high-energy phosphates and glycogen were decreased and ADP, AMP, and lactate increased. Mechanical performance progressively deteriorated in these hearts, and ventricular fibrillation developed after about 20 min (19.8 plus or minus 3.0 min). The data indicate that this preparation is suitable for the study of myocardial metabolism during mild and severe ischemia and may be useful for the evaluation of pharmacological interventions designed for the treatment of myocardial ischemia.
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PMID:Metabolic responses to varying restrictions of coronary blood flow in swine. 111 86


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