Search Results
Results 301 - 350 of 725
< 2 3 4 5 6 7 8 9 10 11 12 >
Beardslee M A - - 2000
Electrical uncoupling at gap junctions during acute myocardial ischemia contributes to conduction abnormalities and reentrant arrhythmias. Increased levels of intracellular Ca(2+) and H(+) and accumulation of amphipathic lipid metabolites during ischemia promote uncoupling, but other mechanisms may play a role. We tested the hypothesis that uncoupling induced by acute ischemia ...
Hauer K - - 2000
AIMS: We assessed whether exercise-induced myocardial ischemia during intensive group exercise sessions can be predicted in patients with coronary artery disease and stable angina pectoris. METHODS AND RESULTS: Twenty-three patients underwent cardiac catheterization, 201-thallium scintigraphy, and exercise testing prior to participation in group training sessions. Heart rates and myocardial ischemia ...
Nakamura S - - 2000
To determine pathways of HCO3- reabsorption in the collecting duct of the mouse kidney, the outer medullary collecting duct (OMCD) and the terminal inner medullary collecting duct (IMCDt) were dissected and perfused at 1 to 2 nL/min, and total CO2 was measured by microfluorometry. In the OMCD, net HCO3- flux ...
Abete P - - 2000
OBJECTIVES: To investigate the effects of ischemic preconditioning in hearts from adult and both sedentary and trained senescent rats. BACKGROUND: Ischemic preconditioning does not prevent postischemic dysfunction in the aging heart, probably because of reduction of cardiac norepinephrine release. Exercise training can reverse the age-related decrease of norepinephrine production. METHODS: ...
Uehara A - - 2000
Some electrocardiographic variables, including the degree of maximal ST-segment depression (STD), may not necessarily indicate the severity of exercise-induced myocardial ischemia. The present study examined whether maximal STD correlates with the severity and extent of exercise-induced myocardial ischemia, as assessed by thallium-201 (201Tl) imaging, and which parameter of exercise testing ...
Yüksel M - - 2000
Liver ischaemia may lead to parenchymal damage depending on the duration of the ischaemia. Dimethylsulphoxide (DMSO), a well-known radical oxygen scavenger, is a protective agent against ischaemia/reperfusion injury. In this study we aimed to investigate the role of hepatobiliary scintigraphy (HBSc) in detecting the protective effect of DMSO. Eighteen rabbits, ...
de Lemos J A - - 2000
Accurate, rapid, and simple noninvasive measures of infarct-related artery (IRA) patency are needed to identify patients with failed coronary reperfusion for rescue percutaneous coronary intervention (PCI). Heart-type Fatty Acid Binding Protein (H-FABP) is a small, cytosolic protein found in high concentrations in the myocardium. We evaluated the efficacy of H-FABP ...
Wieland E - - 2000
OBJECTIVES: Expression of immediate early genes has been reported during reperfusion after ischemia in rat livers due to oxygen radical formation. This study investigates in perfused pig livers the effect of the antioxidant idebenone and of cold ischemia time on the gene expression of c-fos and c-jun. DESIGN AND METHODS: ...
Costa F - - 2000
It has been proposed that adenosine is a metabolic signal that triggers activation of muscle afferents involved in the exercise pressor reflex. Furthermore, exogenous adenosine induces sympathetic activation that mimics the exercise pressor reflex, and blockade of adenosine receptors inhibits sympathetic activation induced by exercise. Thus, we hypothesize that adenosine ...
Hong K - - 2000
We investigated the relationship between the effects of ischemic preconditioning (IPC) and Ca(2+) preconditioning (CPC) on reperfusion-induced arrhythmias. In the control group (noPC), Langendorff-perfused rat hearts were subjected to 5-min zero-flow global ischemia (I) followed by 15-min reperfusion (I/R). In ischemic preconditioning groups (IPC), the hearts were subjected to three ...
Larson J L - - 2000
Previous work has shown that treatment with hyperbaric oxygen significantly reduces neutrophil adhesion to postcapillary venules in a rat microcirculation model of ischemia-reperfusion injury. The mechanism of this process is unknown. The purpose of this study was to evaluate the effect of hyperbaric oxygen on neutrophil CD18 adhesion sites by ...
Parent de Curzon O - - 2000
Abnormalities in calcium homeostasis such as calcium overload have been shown to participate in the pathogenesis of myocardial stunning. The goal of this study was to investigate the effects of mibefradil, a mixed T- and L-type calcium channels antagonist on exercise-induced ischemia (i.e., high-flow ischemia). Nine dogs were permanently instrumented ...
Matsubara T - - 2000
OBJECTIVES: This study focused on 1) the determination of the optimal preconditioning (PC) duration, and 2) the protective effect of nicorandil (NC), a hybrid nitrate with a KATP channel opening effect, during a percutaneous transluminal coronary angioplasty (PTCA) model in humans. BACKGROUND: The ischemic PC effect is induced in 180 ...
Symons J D - - 2000
We hypothesized that exercise training preserves endothelium-dependent relaxation, lessens receptor-mediated constriction of coronary resistance arteries, and reduces myocardial contractile dysfunction in response to ischemia. After 10 wk of treadmill running or cage confinement, regional and global indexes of left ventricular contractile function were not different between trained and sedentary animals ...
Ghosh S - - 2000
BACKGROUND: There are data supporting the existence of ischemic preconditioning in man. This study investigated the most effective preconditioning protocol for the human myocardium and whether the second window of ischemic preconditioning (24 h) is as protective as the first window (< or = 2 h). METHODS AND RESULTS: Right ...
Barron H V - - 2000
The mechanism by which ischemia stimulates angiogenesis is unknown. Adenosine is released during myocardial ischemia and may be a mediator of this process. Experimental data suggest that heparin may enhance this effect. The purpose of this open-labeled, placebo-controlled trial was to determine whether repeated intravenous administration of adenosine and heparin ...
Scheller D - - 2000
Taurine and glutamate were monitored by microdialysis technique during various cerebral insults: a. Application of K+ triggered a cortical spreading depression (CSD). Taurine and glutamate increased concomitantly but recovery of glutamate was faster than that of taurine. b. Application of NMDA induced also CSD but only taurine increased. c. Induction ...
Pasini F L - - 2000
Adenosine is an endogenous nucleoside with multiple biological properties which plays a central role in the pathophysiology of tissue ischemia. Adenosine signals an imbalance between oxygen demand and supply, and it initiates responses to redress such a discrepancy. Besides its vasodilating properties, adenosine possesses anti-platelet and anti-neutrophil activities and provides ...
Murase K - - 2000
An accumulation of recent evidence suggests that the mechanism in ischemic preconditioning (IPC) may involve the activation of protein kinase C (PKC) regulatory pathway. In this study, we examined whether the content of 1,2-diacylglycerol (1,2-DAG) and ceramide, which are intracellular second messengers regulating PKC activity, change during IPC in isolated ...
Tolba R H - - 2000
Celsior, a low viscosity and low potassium preservation solution, has recently been tested successfully in the cold preservation of heart, lung, kidney and small intestine. The purpose of the present study was to evaluate the potential of Celsior in the cold preservation of the liver. Livers were harvested from male ...
Zar H A - - 2000
The ability of mild hypothermia (MH; 34 degrees C) to protect against postischemic endothelial injury and decrease reactive oxygen species' (ROS) formation was studied using lucigenin and luminol enhanced chemiluminescence (CL). Lucigenin CL is largely specific for superoxide, while luminol reacts with many ROS. Isolated rat livers perfused under constant ...
Zafrir N - - 1999
BACKGROUND: The relation between aerobic capacity and extent of exercise-induced myocardial ischemia has not been investigated. Fifty patients with coronary artery disease (>/=50% stenosis) without myocardial infarction underwent cardiopulmonary exercise testing followed by quantitative thallium perfusion imaging. Results were compared with those of age- and sex-matched healthy controls with a ...
Kerensky R A - - 1999
This study examined whether the adenosine receptor antagonist theophylline prevents the warm-up phenomenon in patients with stable angina undergoing serial exercise tests. Our findings offer evidence that adenosine does not play a role in the warm-up phenomenon, and indirectly suggest that the warm-up phenomenon does not represent ischemic preconditioning in ...
Takeyoshi I - - 1999
IL-1 and TNF-alpha are known to be pleiotropic cytokines associated with various inflammatory conditions such as small intestinal injury after ischemia-reperfusion. FR167653 has been characterized as a potent suppressant of IL-1 and TNF-alpha production. The effect of FR167653 on intestinal reperfusion injury was investigated in a warm ischemia model of ...
Rao A M - - 1999
Accumulation of arachidonic acid (AA) is greatest in brain regions most sensitive to transient ischemia. Free AA released after ischemia is either: 1) reincorporated into the membrane phospholipids, or 2) oxidized during reperfusion by lipoxygenases and cyclooxygenases, producing leukotrienes (LT), prostaglandins, thromboxanes and oxygen radicals. AA, its metabolite LTC4 and ...
Hegstad A C - - 1999
The present study focuses on myocardial ultrastructural alterations during the early phase of reperfusion. Isolated buffer-perfused rat hearts were exposed to standard perfusion (control group,n = 10); 60 min of global ischemia (n = 10); 60 min of global ischemia followed by 2 min of reperfusion (n = 10); or ...
O'Donnell J M - - 1999
The transport of metabolites between mitochondria and cytosol via the alpha-ketoglutarate-malate carrier serves to balance flux between the two spans of the tricarboxylic acid (TCA) cycle but is reduced in stunned myocardium. To examine the mechanism for reduced transporter activity, we followed the postischemic response of metabolite influx/efflux from mitochondria ...
Crosson C E - - 1999
PURPOSE: Epinephrine is an effective drug for glaucoma treatment. However, the mechanisms responsible for the ocular hypotensive action of this compound are not completely understood. Adenosine is an autacoid released by all cells. This study evaluated the role of adenosine receptor activation in epinephrine-induced changes in ocular function. METHODS: Rabbits ...
Dutkowski P - - 1999
BACKGROUND: ATP resynthesis during reperfusion after liver preservation has been shown to be well correlated with the function of transplanted grafts. Nevertheless, the advantages of a cellular energy charge loading during the preservation period are yet not fully understood. This study evaluates the effects of different nucleotide levels at the ...
Brock R W - - 1999
A normotensive model of hindlimb ischemia-reperfusion in Wistar rats was used to test the hypothesis that microvascular perfusion deficits contribute to the initiation of remote hepatic injury during a systemic inflammatory response. Animals were randomly assigned to one of three groups: 4 h of ischemia with 6 h of reperfusion ...
Hearse D J - - 1999
The aims of this study were to determine whether 1) like ischemic preconditioning, transient exposure to norepinephrine before ischemia exacerbates contracture during ischemia and 2) protection afforded by norepinephrine is stereospecific (receptor mediated). Isolated perfused rat hearts were randomized into five groups (n = 6/group): 1) ischemic preconditioning (3 min ...
Sawaya D E DE - - 1999
BACKGROUND: We have recently shown that hepatic ischemia/reperfusion (I/R) results in rolling and adherence of leukocytes in terminal hepatic venules (THV) followed by hepatic enzyme elevation and tissue destruction. The objective of this study was to determine the effect of ischemic preconditioning on the recruitment of leukocytes in THV after ...
Stambaugh K - - 1999
BACKGROUND: The cardioprotective effect of preconditioning can be exerted within 1 to 2 hours after initial ischemia, termed classical or early preconditioning, or can reappear 24 hours later as second window or late preconditioning. The objective of this study was to study the interaction between late and early preconditioning and ...
Ross S D - - 1999
BACKGROUND: There is evidence that lung ischemia reperfusion injury is a result of the activation of components of the inflammatory cascade. However, the role of neutrophils in lung reperfusion injury continues to be a source of controversy. METHODS: Using an isolated, whole blood-perfused, ventilated rabbit lung model, we sought to ...
Stone P H - - 1999
OBJECTIVES: The purposes of this database study were to determine: 1) the relationship between mental stress-induced ischemia and ischemia during daily life and during exercise; 2) whether patients who exhibited daily life ischemia experienced greater hemodynamic and catecholamine responses to mental or physical stress than patients who did not exhibit ...
Awan M M - - 1999
Isolated, perfused heart preparations suffer an inevitable peri-operative delay (POD) before retrograde perfusion restores coronary flow. By varying this ischaemic period we investigated the threshold of POD-induced inadvertent preconditioning (PC) in the rat heart. Hearts subjected to POD at 37 degrees C increasing from 1, 2, 3, 5, 10 up ...
Tomai F - - 1999
The aim of the present study was to establish whether exercise-induced ischemia triggers the second window of protection in 15 patients with coronary artery disease undergoing 2 consecutive treadmill exercise tests and a third test 24 hours later. Our findings confirm that a first exercise-induced ischemic challenge induces the early ...
Murphy J F - - 1998
Patients who were stable 1 to 6 months after a cardiac event underwent routine exercise testing with thallium scintigraphy. The prognosis of patients with good exercise capacity (Bruce stage 3) was similar whether or not ischemia was demonstrated and similar to patients with reduced exercise capacity and no ischemia, whereas ...
Casella G - - 1998
OBJECTIVES: This study was designed to better understand the functional correlates and the prognostic relevance of exercise-induced painless ischemia relative to painful ischemia in patients with stable coronary artery disease and previous myocardial infarction (MI). BACKGROUND: The usefulness of exercise testing (ET) for predicting cardiac events, years after MI, although ...
Mandapati R - - 1998
BACKGROUND: Ventricular fibrillation (VF) leads to global ischemia of the heart. After 1 to 2 minutes of onset, the VF rate decreases and appears more organized. The objectives of this study were to determine the effects of no-flow global ischemia on nonlinear wave dynamics and establish the mechanism of ischemia-induced ...
Perlini S - - 1998
Adenosine attenuates the myocardial metabolic and contractile responses induced by ss-adrenergic stimulation. Our study was conducted to investigate the longevity of this antiadrenergic action after adenosine exposure. Adenosine (33 micromol/L) was infused into isolated perfused rat hearts for 1, 5, 30, or 60 minutes, and the adrenergic responsiveness (AR) to ...
Billman G E - - 1998
The activation of the ATP-sensitive potassium channel (KATP) during myocardial ischemia leads to potassium efflux, reductions in action potential duration and the formation of ventricular fibrillation (VF). Drugs that inactivate KATP should prevent these changes and thereby prevent VF. However, most KATP antagonists also alter pancreatic channels, which promote insulin ...
Pickelmann S - - 1998
Hemoglobin-based oxygen carriers have been suggested to enhance the formation of oxygen free radicals, especially under conditions of ischemia-reperfusion (I/R), in which activation and adhesion of leukocytes play a pivotal role for propagation of reperfusion injury. This study investigates the effects of the hemoglobin-based oxygen carrier diaspirin-cross-linked hemoglobin (DCLHb) in ...
Gidday J M - - 1998
PURPOSE: Little is known regarding the status and implications of altered retinal blood flow (RBF) following a period of temporary retinal ischemia. We undertook studies to measure acute changes in RBF after ischemia, and the mechanisms responsible for mediating these changes. METHODS: Retinal ischemia was induced in anesthetized, mechanically ventilated ...
Hofmeister E P - - 1998
Multiple studies have demonstrated that muscle poorly tolerates ischemia. When the ischemic state is unduly prolonged, the successfully replanted or revascularized limb undergoes deleterious biochemical reactions that cascade to vessel intimal damage, increased vessel permeability, and lowering of pH. The resultant tissue edema leads to increasing compartment pressures, which not ...
Juvonen T - - 1998
BACKGROUND: This study was undertaken to confirm earlier findings that retrograde cerebral perfusion (RCP) can improve cerebral outcome after prolonged hypothermic circulatory arrest (HCA), and to determine whether RCP with inferior vena caval occlusion, which is more effective in removing particulate emboli, is superior to conventional RCP in enhancing cerebral ...
Sheps D S - - 1998
The objectives of this study were to compare and contrast indicators of ischemia in a well-characterized group of 196 patients with coronary artery disease, documented angiographically or by verified history of myocardial infarction, and a positive exercise test result. Myocardial ischemia occurs frequently in response to everyday stressors in patients ...
Latini S - - 1998
The temporal correlation between adenosine outflow and changes in field excitatory post synaptic potentials (fEPSP) occurring during ischemia-like conditions was investigated in rat hippocampal slices. Five-minute long ischemia-like conditions resulted in a 100% depression of fEPSP amplitude, followed by a complete recovery after 6-7 min of reperfusion. By reducing the ...
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 ...
< 2 3 4 5 6 7 8 9 10 11 12 >