Search Results
Results 351 - 400 of 727
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Fabian R H - - 1998
We examined the effects of the 21-aminosteroid antioxidant U-74389G (16-desmethyl-tirilazad) on the concentration of extracellular superoxide anion following fluid percussion traumatic brain injury (TBI) measured by a cytochrome c-coated electrode and on local cerebral perfusion (CBFld) measured by laser Doppler flowmetry (LDF). U-74389G in a dose of 3 mg/kg reduced ...
Ashwal S - - 1998
BACKGROUND AND PURPOSE: The present studies examined the hypothesis that the distribution of cerebral injury after a focal ischemic insult is associated with the regional distribution of nitric oxide synthase (NOS) activity. METHODS: Based on previous studies that certain anatomically well-defined areas are prone to become either core or penumbra ...
Hikita H - - 1998
BACKGROUND: Beta-endorphin has been reported to play a role in the mechanism of silent myocardial ischemia. OBJECTIVES: Plasma beta-endorphin levels during coronary angioplasty-induced silent and symptomatic myocardial ischemia were compared with those during exercise-induced silent ischemia. METHODS AND RESULTS: The study population consisted of 40 nondiabetic patients with angioplasty-indicated coronary ...
Feng Z C - - 1998
Inspired oxygen (FiO2) was manipulated during the early reperfusion period after global cerebral ischemia (four-vessel occlusion of 20 or 30 min duration) in anesthetized rats. The goal was to determine whether oxygen availability during the early reperfusion period alters recovery of mitochondrial redox state and evoked electrical activity. The effectiveness ...
Katayama Y - - 1998
The effects of hyperglycemia on brain pyruvate dehydrogenase (PDH) and metabolites (ATP, PCr, and lactate) were investigated at 20 min ischemia, 0, 20, and 60 min, and 4 h reperfusion. During reperfusion, PDH activities were suppressed corresponding to the poor recovery of ATP and PCr concentrations and the increase in ...
Benz S - - 1998
BACKGROUND: Ischemia/reperfusion is thought to play an important role in the development of postimplantation pancreatitis after pancreas transplantation and also in the transition of edematous pancreatitis into necrotizing pancreatitis. Previous studies have suggested that impairment of microcirculation and hence tissue oxygenation and energy metabolism may be critical steps in this ...
Doenst T - - 1998
We tested the hypothesis that glycogen levels at the beginning of ischemia affect lactate production during ischemia and postischemic contractile function. Isolated working rat hearts were perfused at physiological workload with bicarbonate buffer containing glucose (10 mmol/L). Hearts were subjected to four different preconditioning protocols, and cardiac function was assessed ...
Leaf D A - - 1998
BACKGROUND: Free radical injury is implicated in the pathogenesis of coronary artery disease, including atherogenesis and reperfusion/injury. Strenuous physical exercise can cause oxidative stress by several mechanisms, including reperfusion/injury. We hypothesize that exercise-induced lipid peroxidation is greater among those with than those without exercise induced myocardial ischemia. METHODS: The effect ...
Stamler A - - 1998
OBJECTIVE: The lung injury regularly associated with cardiopulmonary bypass (CPB) may be linked to gut mucosal dysfunction occurring as the result of mucosal ischemia associated with nonpulsatile CPB. To examine this possibility we postulated that the weak-beta 2 agonist dopexamine would improve gut mucosal blood flow, thereby decreasing gut and ...
Lipscomb D C - - 1998
BACKGROUND AND PURPOSE: Iron-catalyzed radical generation is a potentially significant mechanism by which extensive tissue acidosis exacerbates brain injury during ischemia/reperfusion. We hypothesized that levels of low-molecular-weight (LMW) iron increase during in vivo global cerebral ischemia in a pH-dependent manner, potentially catalyzing oxidant injury. The present study quantified regional differences ...
Detry O - - 1998
BACKGROUND: The aim of this study was to compare the effects of Euro-Collins and University of Wisconsin solutions on pulmonary mitochondrial function after cold ischemia and subsequent warm reperfusion. METHODS: Seventeen pigs underwent lung harvesting after classical lung flush with either University of Wisconsin or Euro-Collins solutions. The mitochondria were ...
Augustin A J - - 1998
The aim of this study was to investigate the extent to which ischemia and reperfusion lead to oxidative damage of the retinal tissue and investigate how ischemic and reperfused retinal tissues react to the application of perfluorooctylbromide (PFOB) and, if this reaction can be influenced by protective drugs such as ...
Kondo T - - 1998
Although several intravital fluorescence microscopic studies demonstrated that microcirculatory derangement is induced during liver ischemia-reperfusion, these data were obtained from randomly selected microvascular areas and microvessels. Repeated observation of the identical microvessels has not been performed yet. Using a specially designed cover glass, it is now possible to relocate desired ...
Kral B G - - 1997
BACKGROUND: This study was done to determine whether cardiovascular reactivity to mental stress is associated with exercise-induced occult ischemia in an asymptomatic population at high risk for premature coronary heart disease (CHD). METHODS AND RESULTS: One hundred fifty-two siblings of persons with premature CHD underwent mental stress testing. Exercise thallium ...
Shipolini A R - - 1997
BACKGROUND: The sarcolemmal Na+/H+ exchanger has been implicated in the pathogenesis of myocardial injury during ischemia/reperfusion. We determined the cardioprotective efficacy of the Na+/H+ exchanger inhibitor HOE-642 (HOE) as an alternative, adjunct, or additive to cardioplegia (CP). METHODS AND RESULTS: In isolated working rat hearts (n=6 per group) subjected to ...
Horie Y - - 1997
The overall objective of this study was to assess the contribution of an altered bioavailability of nitric oxide (NO) to the leukocyte adhesion and hypoxic stress elicited in the liver by gut ischemia-reperfusion (I/R). The accumulation of leukocytes, number of nonperfused sinusoids (NPS), and NADH autofluorescence were monitored (by intravital ...
Kuroda Y - - 1997
BACKGROUND: Ischemic injury of the microvascular endothelium during cold preservation causes a disturbance of vascular microcirculation after reperfusion and results in graft failure. Recently we have shown that oxygenation of the canine pancreas during preservation by the two-layer method extends the period of preserved pancreatic viability. The aim of this ...
Nielsen V G - - 1997
BACKGROUND: Multiple-organ injury often occurs after aortic occlusion-reperfusion. Oxidants derived from xanthine oxidase have been implicated as a source of injury after aortic occlusion-reperfusion. Halogenated anesthetics modify oxidant-mediated injury. The current study determined if halothane modifies hepatocellular enzyme release (e.g., alanine aminotransferase) and circulating lactate after aortic occlusion-reperfusion. METHODS: Rabbits ...
Portman M A - - 1997
OBJECTIVES: The pH of cardioplegic solutions is postulated to affect myocardial protection during neonatal hypothermic circulatory arrest. Neither optimization of cardioplegic pH nor its influence on intracellular pH during hypothermic circulatory arrest has been previously studied in vivo. Thus we examined the effects of the pH of cardioplegic solutions on ...
Vanden Hoek T L - - 1997
Oxidants such as reactive oxygen species (ROS) have been shown to participate in myocardial ischemia/reperfusion injury. While many studies report a burst of ROS at reperfusion, few reports have presented evidence of significant ROS generation during ischemia. Our previous studies of cultured cardiomyocytes indicated that antioxidants are most effective when ...
Norden M A - - 1997
The purpose of this study was to compare the effects of the University of Wisconsin solution plus butanedione monoxime, the University of Wisconsin solution without butanedione monoxime, and saline on the preservation of muscle tissue. Forty-nine rat hindlimbs were amputated and replanted. The study population was subdivided into four groups ...
Pascher A - - 1997
BACKGROUND: Donor pigs transgenic for human decay-accelerating factor (hDAF) were used in a xenogeneic ex vivo liver perfusion model to study the effect of this modification on the development of hyperacute rejection. METHODS: Three transgenic pigs were hepatectomized after hypothermic portal and transaortal gravity perfusion. Livers from six nontransgenic pigs ...
Soares P R - - 1997
BACKGROUND: Ischemic preconditioning (IPC) attenuates acidosis during prolonged ischemia and improves contractile and metabolic parameters during subsequent reperfusion. Glycogen depletion induced by IPC is proposed as a potential mechanism. METHODS AND RESULTS: We studied the influence of manipulations of preischemic glycogen levels (Pre-G, micromol glucose/g wet wt) on contractile and ...
Müller A - - 1997
Disturbances in gap junction distribution and a decrease in the connexin43 content of the heart were shown to occur after myocardial infarction and in ischemic heart disease, respectively. These changes are now thought to play an important role in the genesis of arrhythmias associated with these diseases. It is thought ...
Eleftheriadis E - - 1997
BACKGROUND/AIMS: The hemodynamic disturbances in the cirrhotic liver following severe variceal bleeding and subsequent restoration by blood transfusion is an ischemia/reperfusion injury event which represents the clinical situation of liver dysfunction. Therefore, the aim of this study was to evaluate the microcirculation, oxygenation and energy charge of the cirrhotic rat ...
Askenasy N - - 1997
Interruption of ischemia by brief reperfusions (I/R) is better tolerated by the heart than continuous ischemia. The present study aims to determine the metabolic profiles of isolated rat hearts during intermittent ischemia, the possible cardioprotective role of adenosine and the influence of I/R on intracellular volumes, using multinuclear NMR spectroscopy. ...
O'Hagan K P - - 1997
Activation of the muscle chemoreflex increases sympathetic drive to skeletal muscle in humans. This study investigated whether activation of the muscle chemoreflex augments the renal sympathetic nerve activity (RSNA) response to dynamic exercise in rabbits. The muscle chemoreflex was evoked by hindlimb ischemia during exercise on a motorized treadmill. Seven ...
Tan Q - - 1997
Decreasing progressive dermal ischemia after burning could theoretically limit the amount of skin necrosis. It is controversial whether the use of free radical scavengers could prevent the progressive dermal ischemia of the postburn stasis zone. We evaluated the effect of superoxide dismutase (SOD) on preventing postburn dermal ischemia in animal ...
Gasbarrini A - - 1997
Sensitivity to ischemia and reperfusion injury is a main problem afflicting tissues exposed to a prolonged period of oxygen deprivation. The generation of oxygen free radicals, in particular, is considered a major cause of postischemic reperfusion injury. However, studies on the mechanisms of production of free radicals are limited by ...
Pérez-Pinzón M A - - 1997
Cerebral injury may occur not only during brain ischemia but also during reperfusion afterward. A characteristic event during reperfusion after cerebral ischemia, or reoxygenation after anoxia in hippocampal slices, is hyperoxidation of the electron carriers of the mitochondrial respiratory chain. Earlier studies suggested that mitochondrial hyperoxidation was produced by an ...
Marcassa C - - 1997
OBJECTIVES: We sought to determine whether the amount of myocardial ischemic burden differs in patients with painful or silent myocardial hypoperfusion during exercise testing. BACKGROUND: Whether a lack of symptoms during ischemia reflects an alteration in pain perception or less myocardium in jeopardy remains a controversial issue. METHODS: We studied ...
Libonati J R - - 1997
We examined the effects of two exercise training modalities, i.e., low-intensity endurance and sprint running, on in vitro, isovolumic myocardial performance following ischemia and reperfusion. Rats ran on a treadmill 5 d.wk-1 for 6 wk at the following levels: endurance; 20 m.min-1, 0% grade, 60 min.d-1 and sprint; five 1-min ...
O'Neill M - - 1997
We tested the hypothesis that cardiac ischemia uncouples the beneficial interaction among hyperkalemia, acidosis, and raised plasma catecholamines when these chemicals are changed to mimic their exercise levels. Potassium chloride, lactic acid, and norepinephrine (NE) were infused intravenously for 2 min into anesthetized, artificially ventilated, thoracotomized rabbits during either occlusion ...
Gu J W - - 1997
BACKGROUND: Basic fibroblast growth factor (bFGF) is a mitogenic polypeptide that demonstrates enhanced expression and promotes angiogenesis in animal models of myocardial ischemia and infarction. Elevated levels of bFGF are present in the urine of humans with metastatic tumors, but its expression in human myocardial ischemia is unknown. Thus, we ...
Nagaoka H - - 1997
The diagnostic values of adenosine, dobutamine, and exercise radionuclide ventriculography (RNVG) in the detection of coronary artery disease (CAD), and the characteristics of those patients who showed myocardial ischemia during the infusion of adenosine or dobutamine were assessed in 41 patients with suspected CAD. Sensitivity, specificity, and accuracy, respectively, for ...
Yabe K - - 1997
OBJECTIVE: The purpose of the present study was to examine the effects of preconditioning on glycolysis and oxidative phosphorylation during reperfusion in perfused rat hearts. METHODS: Preconditioning was induced by 5 min of ischemia and 5 min of reperfusion before 40 min of sustained ischemia and subsequent 30 min of ...
Roberts H C - - 1997
The purpose of this study was to compare a new MR macromolecular contrast medium (MMCM), gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA)-24-cascade-polymer, to a well-studied prototype MMCM, for the potential of distinguishing tissues of varying endothelial permeability. Three tissue models of varying capillary permeability were studied in a total of 46 rats: normal ...
Torosian T - - 1997
This study examined the relationship of psychological, cardiac, and general medical history factors to asymptomatic (silent) versus symptomatic myocardial ischemia among 102 patients who underwent treadmill exercise testing and had perfusion imaging indicative of ischemia. During exercise, 68 patients exhibited silent ischemia, and 34 experienced chest pain. Patients with silent ...
Allos S H - - 1997
Although mesenteric venous thrombosis carries a better prognosis than arterial thrombosis, mortality and morbidity are still high. Previous studies have shown that the basic electrical rhythm (BER) of the bowel decreases early after induction of arterial ischemia. Furthermore, our studies have shown that these changes occur prior to pathologic changes ...
O'Donnell K A - - 1997
Ischemia/reperfusion (I/R) injury to the intestinal mucosa occurs in several commonly encountered clinical situations, such as necrotizing enterocolitis and nonocclusive mesenteric insufficiency. No clinically feasible technique is available for mucosal preservation during ischemia. The goal of this work was to determine whether the continuous intraluminal flow of oxygenated perfluorocarbon (PFC) ...
Rosenblum W I - - 1997
BACKGROUND AND PURPOSE: We previously reported that the endothelium-dependent dilation of pial arterioles by either topical acetylcholine (ACh) or bradykinin (BK) was markedly inhibited after 10 minutes of near total ischemia after bilateral carotid occlusion. The present study tests the responses after 10 minutes of reperfusion and investigates the effect ...
Takasu A - - 1997
Endothelin-1 (ET-1) plays an important role in the physiologic or pathophysiologic regulation of cerebral circulation. To evaluate the effects of the newly synthesized ETA receptor-selective antagonist, BQ-485 (N-perhydroazepin-l-ylcarbonyl-Leu-D-Trp-D-Trp-OH), on the cerebral metabolism of oxygen during the delayed cerebral hypoperfusion that follows global cerebral ischemia, we occluded the ascending aorta and ...
Katayama O - - 1997
BACKGROUND: Addition of adenosine to cardioplegic fluid has been shown to improve myocardial tolerance to ischemia. This study was designed to investigate further this phenomenon to evaluate the dose-response and the temperature dependence of the effect of addition of adenosine to St. Thomas' Hospital cardioplegic solution. METHODS: The isolated working ...
Starkopf J - - 1997
OBJECTIVES: Substantial release of bradykinin has been demonstrated to occur during short periods of myocardial ischaemia in various species. The aim of the present study was to investigate the protective effect of bradykinin in ischaemia and whether bradykinin could be involved in ischaemic preconditioning in the rat heart. METHODS: Isolated, ...
Correa S D - - 1997
The role of adenosine triphosphate-sensitive potassium channels in the adaptive response to demand ischemia was tested in 22 patients treated with placebo or glibenclamide before sequential exercise testing or atrial pacing. Glibenclamide did not affect the improvement in signs of ischemia in both protocols, indicating that opening of these channels ...
Huh S K - - 1997
OBJECTIVE: To evaluate the influence of alpha-melanocyte stimulating hormone (alpha-MSH), an anti-inflammatory antagonist of the production and action of proinflammatory cytokines, 26 dogs were divided into four groups and exposed to isolated, reversible brain stem ischemia in the presence or absence of alpha-MSH treatment. METHODS: Brain stem auditory evoked potentials ...
Wikström B G - - 1997
Adenine nucleotides, lactate and pyruvate were monitored by microdialysis in pig hearts, comprising four experimental groups. Two preconditioned groups, one beta-blocked by metoprolol (0.3 mg kg-1 body wt; n = 6) and the other (n = 7) without beta-blockade. Two groups were not preconditioned, one beta-blocked (n = 6) and ...
Nakai A - - 1997
Recirculation following 2 h of focal ischemia due to transient middle cerebral artery (MCA) occlusion has previously been found to be accompanied by an initial, partial recovery of the cellular bioenergetic state and of mitochondrial respiratory functions, with secondary deterioration during the first 2-4 h of reflow. Both the free ...
Baker J E - - 1997
We describe real-time measurement of myocardial oxygen consumption during ischemia in the intact heart. Measurement of extracellular oxygen concentration during myocardial ischemia by spin label oximetry has been limited by ischemia-induced reduction of the neutral, water-soluble nitroxide TEMPONE. We have overcome this problem by encapsulating the nitroxides. Isolated immature (7-10 ...
Nishikawa E - - 1996
The effectiveness of exercise training in patients with silent myocardial ischemia was examined. Forty patients with coronary heart disease (mean age 55 +/- 8 years) were recruited for a 12-week exercise training program. All patients underwent treadmill exercise stress testing, exercise thallium-201 single photon emission computed tomography and left heart ...
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