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)

U-74006F, 21-(4-(2,6-dipyrrolidinyl-4-pyrimidinyl)-1-piperazinyl)-16 alpha-methylpregan-1,4,9(11)-triene monomethane sulfonate, is currently under development for the treatment of human central nervous system trauma and ischemia. The iv pharmacokinetics and excretion of 14CU-74006F (labeled in the 16 alpha-methyl group) and 3HU-74006F (labeled in a pyrrolidine ring) were investigated in the young adult Sprague-Dawley rat and the perfused rat liver. Following a 3 mg/kg iv bolus dose, plasma levels of 14CU-74006F declined biexponentially with alpha and beta half-times of 8 and 70 min, respectively. The terminal phase volume of distribution was 5.1 liters/kg and the plasma clearance was 51 ml/min/kg, which is similar to the in vivo hepatic plasma flow. Plasma levels of total 14C-labeled metabolites quickly exceeded levels of parent drug and declined with a terminal phase half-time of 50 hr. Greater than 90% of the 14C and 3H doses was excreted in feces with terminal phase half-times of 107 and 46 hr, respectively. Consistent with high hepatic clearance, the oral solution bioavailability of U-74006F was 16%, and the hepatic extraction efficiency of U-74006F from 3% bovine serum albumin (w/v) medium in the perfused liver was 80-86% under nonsaturating conditions at physiological flows. U-74006F was rapidly metabolized in the perfused liver and excreted in bile as metabolites. The biliary excretion mechanism was more easily saturated than hepatic uptake and metabolism, with the consequence that, at pharmacologically relevant perfusate levels of drug, metabolites accumulated in the liver and effluxed into the perfusate.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pharmacokinetics and excretion of the 21-aminosteroid antioxidant U-74006F in rat and perfused rat liver. 257 75

Coronary vascular hemodynamics, albumin permeation, and myocyte contractility were assessed in isolated hearts from 6-mo alloxan-induced diabetic (ALX-D) rabbits during 3 h of reperfusion after 40 min of global no-flow ischemia. Residue-detection data, generated during the single passage of a bolus of 125I-labeled bovine serum albumin (125I-BSA) through the coronary vasculature, were used to estimate indices of vascular function, including the mean transit time of 125I-BSA, the fractional rate of intravascular clearance of 125I-BSA, and 125I-BSA permeation of coronary vessels. During reflow after ischemia in hearts from control rabbits, vascular resistance increased approximately three times that at baseline, left ventricular end-diastolic pressure (LVEDP) increased 8-10 times, and maximum +dP/dt recovered 0.4 times baseline, whereas the fractional rate of washout of intravascular 125I-BSA decreased to less than one-half of baseline values (was prolonged 2-fold), and albumin permeation and mean-transit time were increased 3 and 5 times baseline, respectively. In hearts from diabetic rabbits, vascular resistance was similar to the control group before ischemia but increased only one-third as much during reflow after ischemia. Increases in LVEDP during reflow were approximately 50% lower than controls, and +dP/dt recovered approximately 2.5 times more than in control hearts. 125I-BSA permeation in diabetics was similar to controls before ischemia, but during reflow increased 6 times (approximately 2 times controls). Washout of intravascular 125I-BSA was prolonged approximately 20% versus baseline during 3 h of reflow in hearts from diabetic rabbits. Thus, ALX-D in the rabbit delayed ischemia-reperfusion injury to myocytes and vascular smooth muscle cells while increasing vascular albumin permeation.
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PMID:Myocyte contracture, vascular resistance, and vascular permeability after global ischemia in isolated hearts from alloxan-induced diabetic rabbits. 262 Jul 82

The susceptibility of lung tissue to ischemia-reperfusion injury has made distant procurement of heart-lung allografts difficult. The effects of hypothermia, ventilation without perfusion, and various reperfusion solutions (PSS/Ficoll or whole blood) on the development of ischemia-reperfusion lung injury were investigated. Use of an ex vivo rat lung model in which the above variables were individually varied permitted a direct approach for these studies. Normothermic ischemia for 1 hour caused significant damage, documented by increased iodine 125 bovine serum albumin (125I-BSA) in alveolar lavage fluid and lung parenchyma compared with nonischemic controls. Hypothermic (4 degrees C) ischemia for 4 hours in lungs reperfused with salt solution and for as many as 12 hours in lungs reperfused with whole blood caused no significant increase in 125I-BSA in alveolar lavage fluid and lung parenchyma compared with nonischemic controls. Lungs ventilated without perfusion showed no increase in 125I-BSA leakage compared with controls. The ex vivo rat lung model is excellent for studying ischemia-reperfusion injury. It is reproducible, allows for variance of reperfusion solutions, and permits change in temperature and ventilation easily.
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PMID:Hypothermia or continuous ventilation decreases ischemia-reperfusion injury in an ex vivo rat lung model. 265 79

Intestinal ischemia-reperfusion injury is a common and important clinical event associated with the activation of an endogenous inflammatory response. Some of the mediators of this response may be involved in the pathogenesis of multiple organ system failure. The purpose of this study was to determine whether remote organ dysfunction--specifically, acute lung injury--occurs after intestinal ischemia-reperfusion injury. After an ischemia-reperfusion event in rat intestine, whole lungs were obtained for measurement of tissue adenosine triphosphate (ATP) and myeloperoxidase values, and evaluation of histologic condition. In addition, lung microvascular permeability was assessed by determination of the rate at which iodine 125-labeled bovine serum albumin sequestration in the extravascular compartment occurred. Lung tissue ATP levels were no different in sham-operated animals than in those that had undergone 120 minutes of intestinal ischemia. Within 15 minutes of gut reperfusion, however, lung ATP decreased from 3.82 +/- 0.27 to 1.53 +/- 0.90 x 10(-7) moles/50 mg tissue, p less than 0.05. Neutrophil accumulation in the lungs, estimated by tissue myeloperoxidase determination, increased sevenfold (0.13 +/- 0.02 to 0.97 +/- 0.25 units/gm, p less than 0.05) after 120 minutes of ischemia and 15 minutes of reperfusion. Lung microvascular permeability increased threefold after 120 minutes of intestinal ischemia and 120 minutes of reperfusion (0.10 +/- 0.01 vs. 0.35 +/- 0.05 [lung/blood counts per minute], p less than 0.05). Intestinal ischemia followed by reperfusion is associated with acute lung injury characterized by increased microvascular permeability, histologic evidence of alveolar capillary endothelial cell injury, reduced lung tissue ATP levels, and the pulmonary sequestration of neutrophils. These data confirm an acute lung injury associated with intestinal ischemia-reperfusion and suggest a possible pathogenic role for the neutrophil.
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PMID:Evidence for neutrophil-related acute lung injury after intestinal ischemia-reperfusion. 276 27

Perfusion with human serum albumin decreased myocardial hydrogen peroxide (H2O2) levels (as assessed by inactivation of myocardial catalase activities following aminotriazole pretreatment) and increased myocardial ventricular developed pressures (DP), contractility (+dP/dt) but not relaxation rate (-dP/dt) in isolated crystalloid perfused rat hearts subjected to normothermic global ischemia (20 min) and then reperfusion (40 min). Albumin also decreased H2O2 concentrations in vitro. The findings support the possibility that albumin may act as a protective O2 metabolite scavenger in vivo.
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PMID:Albumin decreases hydrogen peroxide and reperfusion injury in isolated rat hearts. 280 21

Mechanisms of proton conductance (GH) were investigated in phospholipid bilayer membranes containing long-chain fatty acids (lauric, myristic, palmitic, oleic or phytanic). Membranes were formed from diphytanoyl phosphatidylcholine in decane plus chlorodecane (usually 30% vol/vol). Fatty acids were added either to the aqueous phase or to the membrane-forming solution. Proton conductance was calculated from the steady-state total conductance and the H+ diffusion potential produced by a transmembrane pH gradient. Fatty acids caused GH to increase in proportion to the first power of the fatty acid concentration. The GH induced by fatty acids was inhibited by phloretin, low pH and serum albumin. GH was increased by chlorodecane, and the voltage dependence of GH was superlinear. The results suggest that fatty acids act as simple (A- type) proton carriers. The membrane: water partition coefficient (Kp) and adsorption coefficient (beta) were estimated by finding the membrane and aqueous fatty acid concentrations which gave identical values of GH. For palmitic and oleic acids Kp was about 10(5) and beta was about 10(-2) cm. The A- translocation or "flip-flop" rate (ka) was estimated from the value of GH and the fatty acid concentration in the membrane, assuming that A- translocation was the rate limiting step in H+ transport. The kA's were about 10(-4) sec-1, slower than classical weak-acid uncouplers by a factor of 10(5). Although long-chain fatty acids are relatively inefficient H+ carriers, they may cause significant biological H- conductance when present in the membrane at high concentrations, e.g., in ischemia, hypoxia, hormonally induced lipolysis, or certain hereditary disorders, e.g., Refsum's (phytanic acid storage) disease.
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PMID:Proton conductance caused by long-chain fatty acids in phospholipid bilayer membranes. 285 56

We examined the impact of hypoxia-ischemia on high-affinity [3H]glutamate uptake into a synaptosomal fraction prepared from immature rat corpus striatum. In 7-day-old pups the right carotid artery was ligated, and pups were exposed to 8% oxygen for 0, 0.5, 1, or 2.5 h, and allowed to recover for up to 24 h before they were killed. High-affinity glutamate uptakes in striatal synaptosomes derived from tissue ipsilateral and contralateral to ligation were compared. After 1 h of hypoxia plus ischemia, high-affinity glutamate uptake in the striatum was reduced by 54 +/- 13% compared with values from the opposite (nonischemic) side of the brain (p less than 0.01, t test versus ligates not exposed to hypoxia). There were similar declines after 2.5 h of hypoxia-ischemia. Activity remained low after a 1 h recovery period in room air, but after 24 h of recovery, high-affinity glutamate uptake was equal bilaterally. Kinetic analysis revealed that loss of activity could be attributed primarily to a 40% reduction in the number of uptake sites. Hypoxia alone had no effect on high-affinity glutamate uptake although it reduced synaptosomal uptake of [3H]3,4-dihydroxyphenylethylamine. Addition of 1 mg/ml of bovine serum albumin to the incubation medium preferentially stimulated high-affinity glutamate uptake in hypoxic-ischemic brain compared with its effects in normal tissue. These studies demonstrate that hypoxia-ischemia reversibly inhibits high-affinity glutamate uptake and this occurs earlier than the time required to produce neuronal damage in the model.
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PMID:Perinatal hypoxia-ischemia disrupts striatal high-affinity [3H]glutamate uptake into synaptosomes. 287 58

The aim of the present investigation was to evaluate the possible role of arachidonic acid and other free fatty acids in ischemia-induced mitochondrial dysfunction. Respiratory activities were measured in mitochondria isolated from rat brains subjected to 15-30 min of decapitation ischemia. Addition of bovine serum albumin (BSA) to the mitochondria, isolated in BSA-free media, abolished an ischemia-induced increase in substrate-stimulated (state 4) respiration but only partly reversed a marked inhibition of substrate-, phosphate-, and ADP-stimulated (state 3) respiration caused by the ischemia. Individual free fatty acids were measured in aliquots of the same mitochondrial preparations before and after treatment with BSA. There was a significant increase in arachidonic (20:4), stearic (18:0), palmitic (16:0), and docosahexaenoic (22:6) acid during ischemia. BSA treatment removed all 20:4 and reduced the amount of 18:0 and 16:0, but had no significant effect on 22:6. The main conclusions were 1) that 20:4, 18:0, and 16.0 were responsible for the partial uncoupling (increase in state 4 respiration) of mitochondrial respiration during ischemia, 2) that the inhibition of state 3 respiration caused by ischemia could only partly be attributed to an effect of FFAs, and 3) that the ischemia-induced mitochondrial dysfunction was caused by a combination of factors including 20:4.
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PMID:Role of arachidonic acid and other free fatty acids in mitochondrial dysfunction in brain ischemia. 314 27

A single intraperitoneal dose of endotoxin (500 micrograms) shortened the time for development of hepatic coma by 27% in 300-g rats that had an end-to-side portacaval shunt followed within 48 hr by hepatic artery ligation. The body temperature of the rats was maintained at 37 degrees C, and the endotoxin was injected just after the hepatic artery was ligated. Controls were injected similarly with saline. The time to death was also shortened by 27%. A single intravenous dose of immunoglobulin (150 mg) delayed the time from the massive hepatic ischemia to the onset of hepatic coma by 19%. The immunoglobulin was injected just after the portacaval shunt was completed. Controls were injected similarly with 0.6 ml of 25% human serum albumin. While not large, these opposite effects of endotoxin and immunoglobulin were highly significant statistically. These observations complement the findings in human liver failure.
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PMID:Effect of endotoxin and immunoglobulin on the course of experimental hepatic encephalopathy. 322 12

We investigated the role of free radicals in total occlusion ischemia/reperfusion injury (IRI) of rat small intestine (SI), as measured by changes in macromolecular permeability following pretreatment with free radical blockers or scavengers. We also compared susceptibilities to IRI both along the length of the small intestine, and between tissue layers of its wall. In anaesthetised rats, loops of SI were made ischemic for 1-15 min, followed by reperfusion for 0-10 min. Five min prior to killing, 250 mg/kg fluorescein isothiocyanate bovine serum albumin (FITC-BSA) was injected i.v. Tissue was formalin-fixed, sectioned and examined by fluorescence microscopy. FITC-BSA fluorescence was restricted to discrete focal spots (i.e. blood vessel lumina) in control intestine. In tissue made ischemic, but not reperfused, there was little extravasation of FITC-BSA. In reperfused tissue, there was extensive tracer leakage from vessels, predominantly in the mucosa and submucosa. There was also histological evidence of villus tissue damage. The jejunum was more susceptible to IRI than was the mid small intestine which was more susceptible than the ileum. Superoxide or hydroxyl generation blockers or scavengers (allopurinol, dimethyl sulphoxide or superoxide dismutase) failed to prevent extravasation of FITC-BSA in the mucosa and submucosa of reperfused tissue, indicating that these radicals appear to have no crucial role in total occlusion IRI of rat SI.
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PMID:Changes in macromolecular permeability of microvessels in rat small intestine after total occlusion ischemia/reperfusion. 338 65


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