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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 ...
Buus N H - - 2001
BACKGROUND: Myocardial perfusion during adenosine-induced hyperemia is used both in clinical diagnosis of coronary heart disease and for scientific investigations of the myocardial microcirculation. The objective of this study was to clarify whether adenosine-induced hyperemia is dependent on endothelial NO production or is influenced by adrenergic mechanisms. METHODS AND RESULTS: ...
Peart J - - 2001
OBJECTIVES: To characterize the 'anti-ischemic' effects of adenosine metabolism inhibition in ischemic-reperfused myocardium. METHODS: Perfused C57/B16 mouse hearts were subjected to 20 min ischemia 40 min reperfusion in the absence or presence of adenosine deaminase inhibition (50 microM erythro-2-(2-hydroxy-3-nonyl)adenine; EHNA) adenosine kinase inhibition (10 microM iodotubercidin; IODO), or 10 microM ...
Tofovic S P - - 2001
The purpose of this study was to investigate in vivo the effects of modulating the adenosine system on endotoxin-induced release of cytokines and changes in heart performance and neurohumoral status in early, profound endotoxemia in rats. Time/pressure variables of heart performance and blood pressure were recorded continuously, and plasma levels ...
Xia Z - - 2001
Cutaneous burn trauma causes functional inhibition of the heart, but the mechanism is unclear. Using a high dissociation constant (K(D)) calcium indicator TF-BAPTA and 19F MR spectroscopy, the relationship between the changes of cytosolic free calcium and cardiac function after burn trauma was examined. Sprague-Dawley rats received scald (43% TBSA) ...
Sinkovec M - - 2001
Adenosine may be a potential mediator in the pathogenesis of vasovagal syncope. Intravenous adenosine increases sympathetic discharge and provokes vasovagal syncope in sensitive subjects. No data are available for endogenous adenosine. The authors compared the results of head-up tilt-table testing (HUT) (45 minutes at 60 degrees) of three arbitrary groups ...
Meyer T E - - 2001
In the present study, we sought to evaluate whether the antiadrenergic action of adenosine in the heart is altered in pressure overload hypertrophy produced in rats by suprarenal aortic banding. Epicardial and coronary effluent adenosine and inosine concentrations and release were significantly elevated in compensated pressure overload hypertrophy but not ...
Stegen E - - 2001
The effects of adenosine and adenine nucleotides on haemolymph velocity and on heart rate and scaphognathite frequency were investigated in the American lobster Homarus americanus. The infusion of 0.25-2.4 nmol g(-1) min(-1) adenosine produced steady-state concentrations of 2-3 micromol l(-1) adenosine and approximately 80 micromol l(-1) inosine in the haemolymph. ...
Saupe K W - - 2001
In situations such as severe low-flow ischemia, where myocardial work output is low and dependence on anaerobic glycolysis is high, increasing the myocardial supply of glucose and insulin is cardioprotective. Our goal was to determine whether this strategy of "metabolic support" would also be cardioprotective in the moderately hypoperfused heart ...
Alavi-Harati A - - 2001
We have performed studies of the K(0)(L)-->pi(+)pi(-)gamma direct emission ( DE) and inner Bremsstrahlung ( IB) vertices, based on data collected by KTeV during the 1996 Fermilab fixed target run. We find a(1)/a(2) = -0.737+/-0.034 GeV2 for the DE form-factor parameter in the rho-propagator parametrization, and report on fits of ...
Miltényi G - - 2001
Hemodialysis (HD) causes rapid volume shifts and circulatory changes. In chronic renal failure (CRF) Na+/K+ATP-ase is depressed, whereas endogenous digoxin-like factor (EDLF) is elevated. Our aim was to characterize HD-induced cardiovascular adaptation and its possible links to Na+/K+ATP-ase and EDLF. Eleven children with CRF on HD (aged 14.7 +/- 3.7 ...
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