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)

Effects of ergot alkaloids, nicergoline (NIC), on survival rate, brain water content, local cerebral blood flow (LCBF: 14C-iodoantipyrine) and glucose utilization (LCGU: 14C-2-deoxyglucose) were examined after bilateral carotid artery occlusion (BCAO) in spontaneously hypertensive rats. Two series of study were performed; the permanent BCAO and 3-hr-BCAO study. After permanent BCAO, the survival rate at 24 hrs of 32% (8 mg/kg, i.p.) or 38% (16mg/kg) in NIC group was higher than that in non-treated group (12%). At the end of 3-hr-BCAO, the increase in water content (dry-wet) in di-mesencephalon was less in NIC (100 micrograms/kg/min, i.v.) group than that in non-treated group. The decrease in LCBF in caudate-putamen (CP), parietal cortex (PC), thalamus (TH), hypothalamus (HT), and substantia nigra (SN) were less in NIC group than those in non-treated group. At the 2-hr-reperfusion after 3-hr-BCAO, the decrease in LCBF in TH and HT were less in NIC group than those in non-treated group. The LCGU in sensory motor cortex, CP, PC, HT, inferior colliculus and pons-reticular were higher in NIC group than those in non-treated group. From these results, it is concluded that nicergoline may have ameliorative effects on survival rate related to the prevention of decreased cerebral blood flow and metabolism following brain ischemia.
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PMID:[Nicergoline, an ergot alkaloid, improves ischemic brain damage by ameliorating the decreased cerebral blood flow and metabolism in spontaneously hypertensive rats]. 129 29

In order to produce syringomyelia, localized arachnoiditis was created in adult New Zealand albino rabbits and Wistar rats by the injection of kaolin into the thoracic spinal subarachnoid space and incision of the dura mater of the thoracic spinal cord. The rabbits and rats were divided into 3 groups; the control group, dural incision group (DG) and kaolin injection group (KG). Each rabbit was sacrificed at 4, 8, 12 and 16 weeks after the operation. Each rat was sacrificed at 8 and 16 weeks after the operation. Cavity formation in the cord of all rabbits was examined by ultrasound. All animals were perfused with 10% neutral beffered formalin at 150 cm H2O pressure, and histological examination was performed with Luxol fast blue (LFB) and hematoxylin and eosin (H&E) stains. Results obtained: (1) Cavity formation was noted in 6 of 16 DG of rabbit (37.5%), 5 of 16 KG of rabbit (31.2%) and 2 of 9 KG of rat (22.2%) with histological verification. With use of ultrasound, cavity was noted in 3 of 16 DG rabbits (12.5%) and 2 of 16 KG rabbits (18.8%). (2) Cavity formation was present in the cord adjacent to the marked adhesive arachnoiditis both in rabbits and in rats. (3) Cavity was noted in the ischemic area. (4) In 2 rabbits in which kaolin encircled whole surface of the spinal cord, hydromyelia was formed communicating with enlarged central canal caudad from the kaolin subarachnoid block. (5) Histological examination showed obliteration or narrowing of lumen of the small pial vessels involved in the adhesive arachnoiditis. In the cord parenchyma adjacent to the arachnoiditis, multiple spots of demyelination due secondary to ischemia demonstrated by LFB stain were noted. On the other hand, in the cord with the pia-arachnoid remained uninvolved, no demyelination was observed. (6) Localized adhesive arachnoiditis consisted of proliferation of fibrous tissue, lymphocytic infiltration and obliterating processes of small pial vessels involved in it. These data suggest that the cavitation within the cord would be induced by the ischemia, and hydromyelia would be produced by the pressure dissociation between the spinal subarachnoid space and the central canal.
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PMID:[Experimental syringomyelia in rabbits and rats after localized spinal arachnoiditis]. 129 32

Hearts with compensatory pressure-overload hypertrophy show an increased intracardiac activation of angiotensin II that may contribute to ischemic diastolic dysfunction. We studied whether pressure-overload hypertrophy in response to aortic banding would result in exaggerated diastolic dysfunction during low-flow ischemia and whether the specific inhibition of the cardiac angiotensin converting enzyme by enalaprilat would modify systolic and diastolic function during ischemia and reperfusion in either hypertrophied or nonhypertrophied hearts. Isolated, red blood cell-perfused isovolumic nonhypertrophied and hypertrophied rat hearts were subjected to enalaprilat (2.5 x 10(-7) M final concentration) infusion during 20 minutes of baseline perfusion and during 30 minutes of low-flow ischemia and 30 minutes of reperfusion. Coronary flow per gram was similar in nonhypertrophied and hypertrophied hearts during baseline perfusion, ischemia, and reperfusion. At baseline, left ventricular developed pressure was higher in hypertrophied than nonhypertrophied hearts in untreated groups (224 +/- 8 versus 150 +/- 9 mm Hg; p less than 0.01) and in enalaprilat-treated groups (223 +/- 9 versus 145 +/- 8 mm Hg; p less than 0.01). During low-flow ischemia, left ventricular developed pressure was depressed but similar in all groups. All groups showed deterioration of diastolic function; however, left ventricular end-diastolic pressure increased to a significantly higher level in untreated hypertrophied than in nonhypertrophied hearts (65 +/- 7 versus 33 +/- 3 mm Hg; p less than 0.001). Enalaprilat had no effect in nonhypertrophied hearts, but it significantly attenuated the greater increase in left ventricular end-diastolic pressure in hypertrophied hearts treated with enalaprilat compared with no drug (65 +/- 7 versus 50 +/- 5 mm Hg; p less than 0.01). The beneficial effect could not be explained by differences in coronary blood flow per gram left ventricular weight, glycolytic flux as reported by lactate production, myocardial water content, oxygen consumption, and tissue levels of glycogen and high energy phosphate compounds. During reperfusion, all hearts showed a partial recovery of developed pressure to 70-74% of initial values. No effect of enalaprilat could be detected during reperfusion on systolic and diastolic function or restoration of tissue levels of high energy compounds. In conclusion, our experiments show that hypertrophied red blood cell-perfused hearts manifest a severe impairment of left ventricular diastolic relaxation in response to low-flow ischemia in comparison with control hearts. Further, our experiments support the hypothesis that the enhanced conversion of angiotensin I to angiotensin II in rats with pressure-overload hypertrophy contributes to the enhanced sensitivity of hypertrophied hearts to diastolic dysfunction during low-flow ischemia.
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PMID:Exacerbation of left ventricular ischemic diastolic dysfunction by pressure-overload hypertrophy. Modification by specific inhibition of cardiac angiotensin converting enzyme. 131 16

The preservation of the heart and lung for transplantation remains a major concern in extended ischemic intervals. This experimental endeavor evaluates and compares the efficacy of iron chelating agents such as high molecular weight deferoxamine and 21-aminosteroid (U74006F) in a swine model of heart-lung transplantation. Heat-lung blocks were exposed to 4 h and 45 min of ischemia and 2 h of reperfusion. Animals were divided into three groups. Group A was a control without pharmacological intervention. In groups B and C, 21-aminosteroid (U74006F), 10 mg/kg, and high molecular weight deferoxamine, 50 mg/kg, were used, respectively. The results of functional parameters (cardiac index, stroke index, lung water, PO2, PCO2, alveolar-arterial gradient, and alveolar-arterial ratio) demonstrated superior heart and lung function for group C, where high molecular weight deferoxamine was used. Alterations of heart and lung function were significantly more (p less than .001) for control animals and for group B where U74006F was used. This study suggests that formation of hydroxyl radicals was affected by chelation of iron with high molecular weight deferoxamine, which reflects better heart and lung function and consequently less damage to this group of animals. The compound 21-aminosteroid U74006F failed to protect the heart and lung from ischemic-reperfusion injury in this model of heart-lung transplantation.
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PMID:Comparison of new iron chelating agents in the prevention of ischemia/reperfusion injury: a swine model of heart-lung transplantation. 131 95

We assessed the effects of the calcium channel blocker verapamil on postischemic oxidative injury in the rat liver. In the untreated rats, the values of tissue lipid peroxidation products (thiobarbituric acid-reactive substances) remained unchanged during 90 min of warm ischemia. However, the values increased significantly after the next 60 min of reperfusion compared with those in the sham-operated rats (P less than 0.01). Intravenous infusion of verapamil (5 micrograms.kg-1.min-1) significantly reduced the extent of lipid peroxidation during reperfusion compared with that in the untreated rats (P less than 0.02). The percentages of tissue water content and the serum lactate dehydrogenase activities after 60 min of reperfusion were significantly lower in the treated rats than in the untreated rats (P less than 0.02 and P less than 0.01, respectively). We also investigated the influence of verapamil on superoxide-generating activity determined by the superoxide-dependent cytochrome c reduction of peritoneal polymorphonuclear leukocytes (PMNs) harvested from normal, non-ischemic, and non-treated rats in vitro. This demonstrated that there was no apparent effect with the highest verapamil concentration level (8 microM) observed in the rat plasma during our experiment. These findings suggest that verapamil might reduce the postischemic oxidative injury in the rat liver by mechanisms perhaps not related to the suppression of rat PMNs superoxide-generating activity.
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PMID:Verapamil attenuates postischemic oxidative injury in the rat liver. 132 83

Although previous studies have reported that neutrophils play an important role in mediating the microvascular injury observed after reperfusion of ischemic intestine, the contribution of these phagocytic cells to the mucosal dysfunction remains unclear. Three series of experiments consisting of an untreated group, a short-term monoclonal antibody (MAb) IB4 treatment group (MAb IB4 given on the day of the experiment), and a long-term MAb IB4 treatment group (3-day pretreatment with MAb IB4) were performed using autoperfused segments of cat ileum exposed to 3 hours of ischemia followed by 1 hour of reperfusion. Mucosal myeloperoxidase activity, an index of mucosal granulocyte levels, increased from 12 to 25 U/g wet wt in the untreated group. In the short-term MAb IB4 experiments, baseline values were very similar to those of the untreated group but no increase in myeloperoxidase activity was observed after ischemia/reperfusion. Long-term pretreatment with MAb IB4 reduced baseline values of myeloperoxidase activity to approximately 1 U/g wet wt; the values remained at this level throughout the experiment. The permeability of the mucosal barrier was quantitated by measuring blood-to-lumen clearance to 51Cr-ethyl-enediaminetetraacetic acid (EDTA). The water absorptive capacity of the intestine was also measured. In the untreated group, mucosal permeability to 51Cr-EDTA increased sixfold and water absorption was abolished after reperfusion. Both short-term and long-term administration of MAb IB4 prevented the net fluid loss into the lumen, but only long-term administration of MAb IB4 blunted the increased mucosal permeability induced by ischemia/reperfusion. These data suggest that interstitial granulocytes contribute significantly to the mucosal dysfunction associated with reperfusion of the ischemic intestine.
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PMID:Ischemia/reperfusion-induced feline intestinal dysfunction: importance of granulocyte recruitment. 132 98

This study demonstrates ischemic cellular swelling in vivo detected as changes in the concentration of 14C-sucrose pre-perfused into the extracellular space (ECS) as an ECS marker. Microdialysis was utilized as a means of perfusion and measurement of the extracellular concentration of 14C-sucrose ([14C-sucrose]e). Concomitant with an abrupt increase in [K+]e at 1-3 min following the ischemia induction, [14C-sucrose]e was also rapidly elevated. Since sucrose is not taken up by either cells or capillaries, the absolute amount of 14C-sucrose in the ECS must be unchanged. The increase therefore appears to represent a relative decrease in water volume in the ECS resulting from a movement of water into the cells, i.e. cellular swelling. Ca(2+)-free perfusate containing Co2+, which has been shown to block excitatory amino acid release during cerebral ischemia, significantly delayed the increase in [14C-sucrose]e and [K+]e. Kynurenic acid, a broad-spectrum antagonist of excitatory amino acids, administered in situ through the dialysis probe also significantly delayed the increase in [14C-sucrose]e and [K+]e. These findings indicate that the early cellular swelling occurring during cerebral ischemia is a result of massive ionic fluxes mediated by excitatory amino acids which are released by a Ca(2+)-dependent exocytotic process from the nerve terminals.
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PMID:Early cellular swelling during cerebral ischemia in vivo is mediated by excitatory amino acids released from nerve terminals. 132 56

Calcium overload during reperfusion after prolonged ischemia has been associated with the Na(+)-Ca2+ exchange system. It has been proposed that the promotion of Na(+)-Ca2+ exchange at reperfusion may be mediated by Na(+)-H+ exchange. To evaluate whether this hypothesis is applicable for stunned myocardium, we examined the influence of temporary suppression of Na(+)-H+ and/or Na(+)-Ca2+ exchange during early reperfusion in isolated rat hearts. Myocardial stunning was produced by global ischemia for 15 min at 37 degrees C. The initial reperfusate was given during the subsequent 10 min after ischemia, and followed by reperfusion with normal Krebs-Henseleit buffer solution for 40 min. Hemodynamic indices, creatine kinase in coronary effluent, and myocardial water content were measured during reperfusion. The functional recovery of stunned myocardium was improved with higher extracellular Na+ concentration and/or lower Ca2+ concentration of the initial reperfusate. Aortic flow recovery of group II (135 mM Na(+)-0.5 mM Ca2+) was 77.0 +/- 3.4%, which was substantially greater (P < 0.05) than that of other groups: group I (control, 135 mM Na(+)-1.5 mM Ca2+), 68.2 +/- 2.4%; group III (25 mM Na(+)-0.5 mM Ca2+), 48.7 +/- 2.9%; group IV (25 mM Na(+)-1.5 mM Ca2+), 21.6 +/- 1.5%. Administration of amiloride, an inhibitor of Na(+)-H+ exchange, in the initial reperfusate ameliorates cardiac damage and improved aortic flow recovery in a dose-dependent manner (10(-6) M, 70.1 +/- 3.7%; 10(-5) M, 77.3 +/- 1.7%; 10(-4) M, 82.0 +/- 2.1% vs control 68.2 +/- 2.4%).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Possible involvement of Na(+)-H+ exchange in the early phase of reperfusion in myocardial stunning. 133 12

We recently discovered that the endothelium of skeletal muscle capillaries swells in the low-flow ischemia induced by hemorrhagic shock. The present study was undertaken to determine the Na+ transmembrane pathways involved in this swelling, since hypoxic cell swelling is attributed to an influx of Na+ and water. In an initial series of experiments, amiloride (5 mg/kg body wt), which blocks multiple Na+ pathways, was infused intravenously into anesthetized rabbits 30 min prior to shock (40% single-withdrawal hemorrhage). Intravital microscopy of treated capillaries in the rabbit tenuissimus muscle showed that after a 1-h shock period, there was no endothelial cell swelling, as evidenced by no measurable change in the width of red blood cells traversing the capillary. In contrast, the swollen endothelium of untreated capillaries reduced the luminal diameter by 20-25% with a preserved stationary abluminal membrane. The specific effects of amiloride on Na+ transport were investigated with amiloride analogues. Animal pretreatment with 5-(N,N-hexamethylene)amiloride, a selective inhibitor of Na(+)-H+ activity, in a dose of 0.5 mg/kg did not significantly mitigate shock-induced swelling; however, a dose of 1 mg/kg completely prevented it. Phenamil, a selective inhibitor of Na+ channel conductance, even at a potent dosage of 0.5 mg/kg, did not affect swelling. These results suggest a primary role for Na(+)-H+ exchange in endothelial cell swelling during hemorrhagic shock, possibly as a means to regulate cellular pH, which may become acidic during ischemia. Narrowed capillaries with elevated hydraulic resistances could delay and diminish resumption of microcirculatory flow on shock resuscitation.
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PMID:Amiloride-sensitive Na+ pathways in capillary endothelial cell swelling during hemorrhagic shock. 133 33

1H magnetic resonance spectroscopic imaging has been used to obtain metabolite maps of the rat brain. The spin-echo-based technique has been evaluated with respect to water and lipid suppression and sensitivity. Metabolite maps were constructed for choline, creatine + phosphocreatine, amino acids, N-acetyl aspartate, and lactate. A spatial resolution of 3 x 3 mm (in plane) with 7-mm-thick slices was achieved routinely in 60-min (16 x 16 phase encodings) acquisitions. For higher intensity resonances, metabolite maps could be constructed in as little as 10 min. Results from phantoms and from rats under normal and focal ischemia conditions are presented.
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PMID:1H spectroscopic imaging of rat brain at 7 tesla. 135 Jun 55


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