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Shen Weiqun - - 2005
Decreases in total creatine kinase (CK) activity and creatine [Cr] combine to limit the capacity of the failing heart to rapidly re-synthesize ATP (energy reserve). If the loss in energy reserve could be reversed, cardiac contractile reserve may be improved. Here we test whether these changes are reversible during recovery ...
Kisch-Wedel Hille - - 2005
The prostaglandin I2 analogues epoprostenol and iloprost increase left ventricular contractility. Therefore, we hypothesize that the prostaglandin I2 analogues epoprostenol and iloprost improve also left ventricular diastolic function. To test this hypothesis, the effects of epoprostenol and iloprost on left ventricular diastolic function were assessed in vivo and compared to ...
Yao Song T - - 2005
1 The purpose of the present study was to determine whether purines exerted a physiological role in central cardiovascular modulation at the level of the locus coeruleus (LC). 2 In pentobarbitone-anaesthetised Wistar-Kyoto rats, unilateral microinjection of ATP or alpha,beta-methyleneATP into the LC elicited dose-related decreases in blood pressure and heart ...
Mishra Rakesh K - - 2005
OBJECTIVES: The goal of this study was to determine the relationship between changes in cardiac hemodynamics during intravenous adenosine (ADO) infusion, and myocardial blood flow (MBF). BACKGROUND: The relationship between changes in MBF and the peripheral hemodynamic effects during peak adenosine infusion is unknown. METHODS: We studied 348 (age 57 ...
Reichelt Melissa E - - 2005
Adenosine receptors may be important determinants of intrinsic ischemic tolerance. Genetically modified mice were used to examine effects of global A1 adenosine receptor (A1AR) knockout (KO) on function and ischemic tolerance in perfused mouse hearts. Baseline contractile function and heart rate were unaltered by A1AR KO, which was shown to ...
Marin Rodrigo M - - 2005
In isolated rat hearts perfused with HEPES and red blood cell-enriched buffers, we examined changes in left ventricular pressure induced by increases in heart rate or infusion of adenosine to investigate whether the negative force-frequency relation and the positive inotropic effect of adenosine are related to an inadequate oxygen supply ...
Schaddelee Marloes P - - 2004
The objective of this investigation was to characterise the pharmacokinetic-pharmacodynamic correlation of 5'-deoxy-N6-cyclopentyl-adenosine (5'dCPA) in the chronic constriction injury model of neuropathic pain. Following intravenous administration of 5'dCPA (0.30 or 0.75 mg kg(-1)), the time course of the drug concentration in plasma was determined in conjunction with the effect on ...
Burki Nausherwan K - - 2005
Intravenous adenosine for the treatment of supraventricular tachycardia is reported to cause bronchospasm and dyspnea and to increase ventilation in humans, but these effects have not been systematically studied. We therefore compared the effects of 10 mg of intravenous adenosine with placebo in 21 normal subjects under normoxic conditions and ...
Wyon Matthew A - - 2004
The aim of the present study was to examine whether the workload, expressed in oxygen uptake and heart rate, during dance class and rehearsal prepared the dancer for performance. Previous research on the demands of class and performance has been affected by equipment limitations and could only provide limited insight ...
Shen Fu-Ming - - 2004
With a computerized analysis system, blood pressure was recorded continuously in conscious unrestrained spontaneously hypertensive rats. The effects of different adenosine receptor agonists and ATP-sensitive potassium channel opener and blocker on blood pressure variability in spontaneously hypertensive rats were studied. It was found that adenosine, 5'-N-cyclopropyl-carboxamidoadenosine (CPCA, a selective adenosine ...
Ziyatdinova N I - - 2004
The effects of electrical stimulation of the vagus nerve on the negative chronotropic and hypotensive effects of adenosine were studied on adult rats. Intravenous injection of adenosine to control rats significantly reduced the heart rate and induced a transient blood pressure drop followed its increase. Preliminary electrical stimulation of the ...
Konno Takashi - - 2004
We evaluated the activities of 2-alkynyladenosine derivatives, relatively selective adenosine A2 receptor agonists, in the intraocular pressure regulation in rabbits. An adenosine A2 receptor agonist 2-[p-(2-carboxyethyl)phenylethylamino]-5'-N-ethylcarboxamidoadenosine (CGS-21680) decreased intraocular pressure, while another A2 receptor agonist 2-(phenylamino)adenosine transiently increased it. The first group of 2-alkynyladenosine derivatives (1-hexyn-1-yl derivatives) caused a transient ...
Ng Cho - - 2004
OBJECTIVE: To determine the effect of adenosine for the management of persistent pulmonary hypertension of the newborn. DESIGN: Prospective, observational case series report. SETTING: A single, tertiary referral neonatal intensive care unit. PATIENTS: Nine neonates with persistent pulmonary hypertension of the newborn requiring mechanical ventilation and inhaled nitric oxide at ...
Timmers Henri J L M - - 2004
The direct vasodilatory and negative chronotropic effects of adenosine in humans are counterbalanced by a reflex increase in sympathetic nerve traffic. A suggested mechanism for this reflex includes peripheral chemoreceptor activation. We, therefore, assessed the contribution of carotid chemoreceptors to sympatho-excitation by adenosine. Muscle sympathetic nerve activity was recorded during ...
Kisch-Wedel Hille - - 2003
OBJECTIVE: The principal effects of prostaglandin I(2) are vasodilation and inhibition of platelet aggregation induced by a rise in the intracellular second messenger cAMP. In the heart a rise in intracellular myocardial cAMP increases contractility. We examined whether prostaglandin I(2) increases left ventricular contractility in vivo. The effects of epoprostenol ...
Leesar Massoud A - - 2003
OBJECTIVES: The objective of this study was to use electrocardiogram (ECG)-independent parameters to determine whether preconditioning (PC) exists in humans during percutaneous transluminal coronary angioplasty (PTCA). BACKGROUND: Several studies suggest that both ischemia and adenosine induce PC in the human heart during PTCA. However, because almost all of these studies ...
Leong H S - - 2003
Cardiac hypertrophy, induced by chronic pressure or volume overload, is associated with abnormalities in energy metabolism as well as characteristic increases in muscle mass and alterations in the structure of the heart. Hypertrophied hearts display increased rates of glycolysis and overall glucose utilization, but rates of pyruvate oxidation do not ...
Bin Jian-Ping - - 2003
The direct effects of dobutamine on capillary blood volume (VOL) and blood flow velocity (VEL) are not known. We hypothesized that these would be more similar to that of adenosine because of its effects on the beta(2) receptors on the coronary circulation. A total of 9 open-chest anesthetized dogs were ...
Hoffman William E - - 2003
OBJECTIVE: To compare adenosine-, isoflurane-, or desflurane-induced hypotension with and without left anterior descending (LAD) coronary artery constriction for the effects on myocardial tissue oxygen pressure (PmO(2)) in dogs. DESIGN: Prospective, randomized, nonblinded. SETTING: University teaching hospital. PARTICIPANTS: Male nonpurpose-bred dogs (n = 18). INTERVENTIONS: Dogs were anesthetized with 1.5% ...
Rich Preston B - - 2003
BACKGROUND: Extracellular nucleotides mediate many cellular functions and are released in response to mechanical stress in vitro. It is unknown whether adenosine triphosphate (ATP) is released in vivo during mechanical ventilation (MV). We hypothesized that stress from high-pressure MV would increase airway ATP, contributing to MV-associated lung edema. METHODS: Rats ...
Dobson Geoffrey P - - 2003
1. From the smallest shrew or bumble-bee bat to the largest blue whale, heart size varies by over seven orders of magnitude (from 12 mg to 600 kg). This study reviews the scaling relationships between heart design, cellular bioenergetics and mitochondrial efficiencies in mammals of different body sizes. 2. The ...
Mielke Marilyn M Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, - - 2003
Activation of the Na(+)/H(+) exchanger may play an important role in the development of cardiac hypertrophy. Isolated ventricular myocyte studies have suggested that angiotensin II (AII) has direct positive inotropic effect caused by intracellular alkalinization due to increased Na(+)/H(+) exchange, but whether this occurs in the whole heart is unknown. ...
Hua Dongping - - 2003
BACKGROUND: In this study, we evaluated the effects of fructose-1,6-diphosphate (FDP) on high-energy phosphate metabolism during 18-hour hypothermic rabbit-heart preservation. METHODS: Under general anesthesia and artificial ventilation, hearts from 42 adult New Zealand white rabbits were harvested, flushed, and preserved in St. Thomas solution at 4(o)C for 18 hours. In ...
Follath Ferenc - - 2003
The novel calcium sensitizer levosimendan improves myocardial contractility without causing an increase in intracellular calcium and cyclic adenosine monophosphate concentrations. It also has a vasodilator action due to an opening of the adenosine triphosphate-sensitive potassium channels. In a double-blind clinical trial levosimendan was compared with dobutamine in 203 patients with ...
Tawakol Ahmed - - 2003
OBJECTIVE: This study tests the hypothesis that elevated levels of rest myocardial blood flow (MBF), indicative of inefficient aerobic metabolism, will be present in some patients with mitochondrial disorders but structurally normal hearts. BACKGROUND: Regulation of MBF is a complex process closely linked to myocardial energy production. Aerobic metabolism in ...
McConville Patrick - - 2003
BACKGROUND: In the heart, striking functional differences exist after stimulation of the beta1- and beta2-adrenergic receptor (AR) subtypes. These may be linked to differences in metabolic response during beta1- and beta2-AR stimulation. METHODS AND RESULTS: The relation between work and metabolism was examined during selective beta1- and beta2-AR stimulation (beta1 ...
Kojic Zvezdana Z - - 2003
To test whether endothelium-derived nitric oxide (NO) regulates mitochondrial respiration, NO was pharmacologically modulated in isolated mouse hearts, which were perfused at constant flow to sensitively detect small changes in myocardial O2 consumption (MVO2). Stimulation of NO formation by 10 microM bradykinin (BK) increased coronary venous nitrite release fivefold to ...
Rose'Meyer Roselyn B - - 2003
In this study, we investigated the effect of noradrenaline depletion on contractile recovery in rat isolated heart following myocardial ischaemia. Groups tested included control tissues and hearts from reserpinised rats. Reserpine 1 mg/kg s.c. was injected into rats 18 to 24 h prior to experiments. Hearts underwent 15 min global ...
Hoffman W E - - 2003
BACKGROUND: Reports show that glyburide, an adenosine triphosphate sensitive potassium (K+ATP) channel blocker, will reverse the myocardial protective effect of inhalational anesthesia. We evaluated the effect of glyburide on myocardial tissue oxygen pressure (PmO2) in dogs anesthetized with desflurane. METHODS: Twelve dogs were anesthetized with 8% end-tidal desflurane for baseline ...
Agnihotri Arvind K - - 2003
BACKGROUND: Micropump additive systems allow for continuous modification of cardioplegia composition during heart surgery. Although the use of such systems in warm heart surgery is theoretically desirable, the role of the systems has been clinically limited by coronary vasoreactivity with higher potassium concentration and unreliable mechanical arrest at lower potassium ...
Nalos Marek - - 2003
BACKGROUND: Despite aggressive resuscitation shock often results in multiple-organ failure characterized by increased energy demands of organs and decreased ability of effective energy production. The administration of ATP-MgCl(2) as a supportive measure has been investigated in various animal models of ischemia/reperfusion injury and hemorrhagic, endotoxic, and septic shock. INVESTIGATIONS: These ...
Totaro Rocco - - 2002
This study evaluated the effects of two different rates of infusion of echo-contrast agents (ECA) on signal enhancement. A total of 15 patients with insufficient Doppler signal due to inadequate transtemporal acoustic bone window were examined. Signal from the middle cerebral artery was recorded during the IV infusion of Levovist ...
Fabian Matthew J - - 2002
BACKGROUND: The purposes of this study were to determine how clinically relevant levels of acute ethanol (EtOH) influence cerebral perfusion pressure (CPP), cerebral venous O saturation (Scvo ), and systemic hemodynamics after fluid resuscitation from traumatic brain injury (TBI); and to test the hypothesis that the actions of EtOH on ...
Komukai Kimiaki - - 2002
Continuous ATP injection is used clinically for Tl imaging or coronary flow measurement and because the effect on human hemodynamics is unknown, the present study investigated it in 14 patients undergoing heart catheter examination. Continuous ATP injection induced chest symptoms in 13 of the patients and second-degree atrioventricular block in ...
Martin Timothy J - - 2002
The mediators of bronchoconstriction of isolated lungs and trachea from ovalbumen sensitized guinea-pigs to adenosine and ovalbumen were examined using relevant antagonists. Changes in perfusion pressure and tension of paired lung halves and tracheal spiral strips, respectively, were recorded in response to adenosine (1 mM lung, 300 microM trachea), histamine ...
Zheng Xiao Ming - - 2002
BACKGROUND: Caffeine binds to the A2 receptors and inhibits adenosine's action of vasodilation or dipyridamole-induced vasodilation. Patients scheduled for (201)Tl myocardial perfusion using pharmacologic stress with dipyridamole or adenosine are advised to abstain from caffeine for 24 h before the test. This article reports on the residual serum caffeine levels ...
Zima Endre - - 2002
Pericardial fluid accumulates the cardioprotective purine metabolites, as well as the endogenous vasoconstrictor agent endothelin-1 (ET-1). The aim of the present study was to characterize the pericardial concentrations of the purine metabolites adenosine, inosine and hypoxanthine before and after intrapericardial administration of ET-1 to the in situ heart. The closed ...
Kékesi Violetta - - 2002
It has been shown that the adenosine concentration in the pericardial fluid of the normal heart is higher by one order of magnitude than that of the venous plasma. A further increase in the pericardial adenosine concentration was also demonstrated in myocardial ischaemia or hypoxia. It was proposed that pericardial ...
Carlucci F - - 2002
Compared to murine and human hemoglobin, bovine hemoglobin has a less exothermic oxygen binding and delivers oxygen even at low temperatures. This property could improve oxygen availability for myocytes during hypothermic arrest of hearts. The aim of this study was to evaluate the advantage of using cardioplegic solutions enriched with ...
Gutzwiller Jean-Pierre - - 2002
BACKGROUND: Half of the dialysis population suffers from hyperphosphataemia, which is now recognized as a major factor of haemodialysis (HD) morbidity and mortality. Current control is focussed on reducing dietary phosphate intake and diminishing absorption using phosphate binders, whereas control and quantification of phosphate removal by HD is undervalued. The ...
Lucas David G DG - - 2002
BACKGROUND: Elaboration of a number of bioactive substances, including adenosine, occurs in heart failure (HF). Adenosine, through the adenosine subtype 1 (A1) receptor, can reduce renal perfusion pressure and glomerular filtration rate and increase tubular sodium reabsorption, which can affect natriuresis and aquaresis. Accordingly, the present study examined the acute ...
Goldfarb Roy D - - 2002
OBJECTIVE: To determine whether activation of the nuclear enzyme poly(adenosine 5'-diphosphate [ADP]-ribose) synthetase (PARS) contributes to mortality rate, myocardial dysfunction, and cardiovascular collapse in a porcine model of sepsis induced by implantation of an infected clot. DESIGN: Prospective, random animal study. SETTING: Research laboratory at Rush Presbyterian St. Luke's Medical ...
Cerniway Rachael J - - 2002
Myocardial A1 adenosine receptor (A1AR) overexpression protects hearts from ischemia-reperfusion injury; however, the effects during anoxia are unknown. We evaluated responses to anoxia-reoxygenation in wild-type (WT) and transgenic (Trans) hearts with approximately 200-fold overexpression of A1ARs. Langendorff perfused hearts underwent 20 min anoxia followed by 30 min reoxygenation. In WT ...
Dobson Geoffrey P - - 2002
Our aim was to estimate a number of bioenergetic parameters in the beating mouse, rat and guinea pig heart in situ and compare the values to those in hearts of mammals over a 2000-fold range in body mass. For the mouse, rat and guinea pig heart, we report a phosphorylation ...
Thompson Paul D - - 2002
BACKGROUND: Studies on the effect of estrogen on atherosclerotic coronary artery disease (CAD) risk in women have produced conflicting results. Similar confusion, but fewer data, exists on the effect of testosterone on CAD risk in men. METHODS: We used 99mTc sestamibi single-photon emission computed tomography (SPECT) myocardial perfusion imaging to ...
Kilian G - - 2002
Although the role of creatine in muscle metabolism is well understood, there is still uncertainty as to its effects at supplemented levels. With this in mind, this study was designed to investigate the direct effects of commercially available creatine on the isolated rat heart, retrogradely perfused and infused with varying ...
Ikeuchi Yoshihide - - 2002
Ikkai & Ooi [Ikkai, T. & Ooi, T. (1966) Biochemistry 5, 1551-1560] made a thorough study of the effect of pressure on G- and F-actins. However, all of the measurements in their study were made after the release of pressure. In the present experiment in situ observations were attempted by ...
Shah Mrugeshkumar K - - 2002
The mechanism by which purinergic agonist adenosine triphosphate (ATP) and uridine triphosphate (UTP) decrease systemic arterial pressure in the anesthetized mouse was investigated. Intravenous injections of adenosine triphosphate (ATP) and uridine triphosphate (UTP) produced dose-dependent decreases in systemic blood pressure in the mouse. The order of potency was ATP > ...
Vinereanu D - - 2002
Adenosine stress echocardiography was performed in nine patients (58 (+/-3) years, eight women) with documented microvascular angina. Global ventricular function was assessed by Tc(99m) blood pool imaging and Doppler, whereas longitudinal ventricular function was assessed by simultaneous tissue Doppler echocardiography of the lateral mitral annulus. Adenosine was infused incrementally to ...
Ren Yilin - - 2002
BACKGROUND: The macula densa (MD), a plaque of specialized tubular epithelial cells, senses changes in tubular NaCl concentration and sends a signal(s) that controls the resistance of the glomerular afferent arteriole (Af-Art). This mechanism, called tubuloglomerular feedback (TGF), is thought to be important in the homeostasis of body fluids and ...
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