Over the past decade, national and international guidelines have proposed beta-blockers to be used on an equal footing with diuretics for initial therapy of hypertension. This preferred status was supposedly based on evidence documenting a reduction in morbidity and mortality with beta-blocker therapy in hypertension. We systematically analyzed all available ...

Dielectric spectra of the polyalcohols sorbitol and xylitol were measured under isobaric pressures up to 1.8 GPa. At elevated pressure, the separation between the alpha and beta relaxation peaks is larger than at ambient pressure, enabling the beta relaxation times to be unambiguously determined. Taking advantage of this, we show ...

This study was undertaken to investigate the possible negative effect of beta-blockers on skin microcirculation in patients with intermittent claudication and hypertension. Methods and materials In this clinical crossover study, 20 patients with mild to moderate hypertension, treated with long-term beta-blockade, and intermittent claudication or ischemic rest pain, underwent assessment ...

BACKGROUND: Adrenergic receptor blockers used in the treatment of heart failure have distinct receptor affinity profiles. We hypothesized that alpha-adrenergic-blocking effects of carvedilol would limit vasoconstriction in response to adrenergic stimuli when compared with metoprolol. METHODS AND RESULTS: Forearm vascular resistance responses to isometric handgrip and cold pressor test were ...

Our understanding of avian embryonic cardiovascular regulation has been based on studies in chickens. The present study was undertaken to determine if the patterns established in chickens are generally applicable to the emu, a ratite bird species. We studied cardiovascular physiology over the interval from 60% to 90% of the ...

The QT interval corrected for heart rate (QTc) is believed to reflect sympathovagal balance. It has also been established that beta-blockers and dihydropyridine-type calcium channel blockers (DHPCCB) influence the autonomic nervous system. This study tested the hypothesis that QTc interval length is a predictor of the blood pressure reduction induced ...

OBJECTIVE: To investigate the value of the echocardiographic observation of the left ventricular hypertrophy (LVH) in diagnosing myocardial microvascular damage in patients with essential hypertension (EH). METHODS: After intravenous injection with Quanfuxian (a contrast agent consisting of albumin and C3F8 prepared by Nanfang Hospital), the values of A (the maximum ...

Common naturally occurring polymorphisms have been identified in the coding regions of the alpha(1A)-, alpha(2B)-, beta(1)- and beta(2)-adrenoceptor (AR) genes [alpha(1A)-AR R492C, alpha(2B)-AR insertion/deletion (I/D), beta(1)-AR R389G, beta(2)-AR G16R and beta(2)-AR Q27E] and are associated with modified in vivo and in vitro functionality. We tested their possible effects on the ...

High factor VIII (FVIII) is a risk factor for venous thromboembolism (VTE). The pathomechanism by which high FVIII leads to an increased risk of VTE is unknown. Physical activity and infusion of adrenalin provoke a rise in FVIII, which can be blocked by a nonselective beta-blockade. We tested the hypothesis ...

BACKGROUND: A common polymorphism of the beta(1)-adrenergic receptor Arg389Gly markedly affects function in vitro, but little is known about its in vivo significance. METHODS AND RESULTS: Resting and exercise hemodynamic responses were measured in subjects homozygous for Arg389 (n = 21) or Gly389 (n = 13) alleles before and 3 ...

Maximal left ventricular (LV) hydraulic power output (PWR(max)), corrected for preload as PWR(max)/(V(ed))(beta) (where V(ed) is the end-diastolic volume and beta is a constant coefficient), is an index of LV contractility. Whereas preload-adjusted maximal power (PAMP) is usually calculated with beta = 2, there is uncertainty about the optimal value ...

Alterations in general characteristics and morphology of the heart, as well as changes in hemodynamics, myosin heavy chain isoforms, and beta-adrenoceptor responsiveness, were determined in Sprague-Dawley rats at 1, 2, 4, 8, and 16 wk after aortocaval fistula (shunt) was induced by the needle technique. Three stages of cardiac hypertrophy ...

Bovine beta-lactoglobulin was hydrolyzed with trypsin or chymotrypsin before, during and after treatment at 600 MPa and pH 6.8 for 10 min at 30, 37 and 44 degrees C. The extent of beta-lactoglobulin hydrolysis under pressure was noticeably higher than at atmospheric pressure, particularly when chymotrypsin was used. Addition of ...

BACKGROUND: A degree of reduction of heart rate (HR) and blood pressure (BP) values following beta-blocker administration has been shown to indicate beta-blockade effectiveness. Whether this parameter is also useful in the identification of patients with vaso-vagal syncope (VVS) who could benefit from beta-blocker therapy, has not yet been established. ...

AIMS: To assess the tolerability, safety and efficacy of the epoetin beta multidose cartridge formulation, self-administered subcutaneously via a pen device (Reco-Pen), in adult patients with renal anemia. METHODS: Patients receiving maintenance epoetin therapy were switched to the subcutaneous (SC) multidose formulation of epoetin beta (NeoRecormon). The frequency of adverse ...

Recent studies indicate that the human choroid has a considerable capacity to keep blood flow constant despite exercise-induced increases in perfusion pressure. The mechanisms underlying this vasoconstrictor response remain unclear. We hypothesized that pharmacological modulation of the autonomic nervous system may alter the choroidal pressure/flow relationship during squatting. To test ...

The authors used high and low responders to novelty (HRs and LRs, respectively) to examine the effects of noradrenergic injections into the nucleus accumbens using a special radial-maze task. During the 5 successive test days, solvent-treated HRs acquired this task faster than LRs. Isoproterenol (beta-agonist) combined with phenylephrine (alpha-agonist) improved ...

Despite the fact that beta-blockers have been used for the treatment of hypertension for more than 30 years, no study has shown that their use reduces morbidity and mortality in the elderly. To the contrary, the British Medical Research Council trial in the elderly documented that although blood pressure was ...

This study examines the effects of competition and competitiveness on hemodynamics. Cardiovascular activity was measured in 27 men at resting baseline and during a car racing game, which comprised a solo race against time and three races against an experimenter. To assess hematocrit, blood was collected at rest and after ...

OBJECTIVE: The goal of this study was to determine whether the cardiostimulant effects of the endogenous beta(1)-adrenergic receptor (AR) agonist, (-)-norepinephrine are modified by polymorphic (Serine49Glycine [Ser49Gly], Glycine389Arginine [Gly389Arg]) variants of beta(1)-ARs in the nonfailing adult human heart. BACKGROUND: Human heart beta(1)-ARs perform a crucial role in mediating the cardiostimulant ...

OBJECTIVE: We compared the hemodynamic effects of dobutamine and enoximone administration before and after long-term beta-blocker therapy with metoprolol or carvedilol in patients with chronic heart failure (HF). BACKGROUND: Patients with HF on beta-blocker therapy may need hemodynamic support with inotropic agents, and the hemodynamic response may be influenced by ...

OBJECTIVE: To investigate the major cardiovascular effects of human plasma "new pressor protein" (NPP) and how the adrenal medulla contributes to these effects. METHODS: NPP was injected into bioassay rats intravenously, and the effects on blood pressure and cardiac function were investigated. Acute adrenal medullectomy (2MDX), alpha- and beta-adrenergic blockade ...

The beta(3)-adrenergic receptor (beta(3)AR) plays a critical role in lipid metabolism, and thus alterations in its function may be involved in the metabolic syndrome. Indeed, we have found previously that the Trp64Arg amino acid variant of the beta(3)AR is associated with hypertension and higher serum triacylglycerol levels in the Sardinian ...

The identity and amounts of intracellular solutes in the deep-sea bacterium Photobacterium profundum strain SS9 were studied using nuclear magnetic resonance techniques. P. profundum strain SS9, a moderate piezophile which grows optimally at 20-30 MPa primarily accumulated glutamate and betaine, with lesser amounts of alanine, beta-hydroxybutyrate (beta-HB) and oligomers composed ...

In this study we evaluated the contractile characteristics of sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA)1a-expressing hearts ex vivo and in vivo and in particular their response to beta-adrenergic stimulation. Analysis of isolated, work-performing hearts revealed that transgenic (TG) hearts develop much higher maximal rates of contraction and relaxation than wild-type (WT) hearts. ...

The present study was undertaken to assess the effect of hyperthyroidism on stiffness in the common carotid artery (CCA) in patients with Graves' disease (GD) and elucidate the mechanism by which arterial stiffness is increased in hyperthyroidism. The arterial stiffness index beta (stiffness beta) was evaluated in the CCA using ...

1. The aim of the present study was to investigate the effects of alpha-adrenoceptor blockade (phentolamine), beta-adrenoceptor blockade (propranolol), neuropeptide Y(1) receptor blockade and neurogenic blockade (brachial plexus) on endothelium-dependent vasodilation (EDV) in the human forearm. 2. Forty-four young healthy volunteers underwent forearm blood flow (FBF) measurements, using venous occlusion ...

alpha 1-adrenergic receptors (ARs) play a major role in blood pressure regulation. The three alpha 1-AR subtypes (A/C, B, and D) stimulate contraction of isolated arteries, but it is uncertain how different subtypes contribute to blood pressure regulation in the intact animal. We studied the role of the alpha 1A/C ...

In patients with myocardial infarction (MI), an expansion of the remote normal regions of the left ventricle is often observed. However, the characteristics of such regions are not fully understood. Thus, we investigated this issue from the standpoint of myocardial oxidative metabolism using (11)C-acetate PET. METHODS: In 33 patients with ...

According to a model of the turbulent boundary layer that we propose, in the absence of external turbulence the intermediate region between the viscous sublayer and the external flow consists of two sharply separated self-similar structures. The velocity distribution in these structures is described by two different scaling laws. The ...

BACKGROUND: Baroreflex sensitivity declines with age, creating a fall in systolic blood pressure and pulse pressure when standing. If, in addition, blood pressure is reduced as a result of antihypertensive medication, compensatory mechanisms may be inadequate and orthostatic problems may occur. This may be less true in patients on beta-blockers. ...

Cardiovascular regulation is tightly controlled by signaling through G protein-coupled receptors (GPCRs). beta-Adrenergic receptors (ARs) are GPCRs that regulate inotropy and chronotropy in the heart and mediate vasodilation, which critically influences systemic vascular resistance. GPCR kinases (GRKs), including GRK2 (or betaARK1), phosphorylate and desensitize agonist-activated betaARs. Myocardial GRK2 levels are ...

OBJECTIVE: Our objective was to investigate the thermogenic efficacy of single oral doses of the novel beta(3)-adrenergic receptor agonist L-796568 [(R )-N -[4-[2-[[2-hydroxy-2-(3-pyridinyl)ethyl]amino]ethyl]-phenyl]-4-[4-[4-(trifluoromethyl)phenyl]thiazol-2-yl]-benzenesulfonamide, dihydrochloride] in humans. METHODS: Twelve healthy overweight to obese men participated in this 2-center, 3-period, randomized, placebo-controlled, crossover trial. In each period subjects received 250 mg L-796568, ...

The present study was carried out to determine, first, the cardiac beta-adrenergic receptor characteristics of broiler chick embryos exposed to two different CO(2) levels during the last stage of embryonic development, and second, the prophylactic effect of beta(1)-adrenoceptor blocker on right ventricular hypertrophy in broiler chickens. High CO(2) embryos showed ...

The urethral response to a sudden forced dilation was studied in ten healthy male volunteers aged from 27 to 71 years. Measurements were performed from the bladder neck and beyond the region of high pressure using a specially designed probe. The pressure response after dilation showed a characteristic course, which ...

The significance of the anatomical location and age on the urethral response to a sudden forced dilation was studied in 30 healthy males aged 23-85 years. The pressure decay after dilation was fitted with a double exponential function of the form: P(t) = P(equ) + P(alpha)e(-t/tau(alpha) + P(beta)e(t/tau(beta) where P(t) ...

BACKGROUND: This study investigated the changes of catecholamine responsiveness and beta-adrenergic receptor/adenylyl cyclase pathway during acute cardiac transplant rejection. METHODS: Isogeneic Lewis to Lewis and allogeneic Dark Agouti (DA) to Lewis rat cardiac transplants were studied 3 and 5 days after heterotopic intraabdominal transplantation (n=6/group). Myocardial blood flow (MBF), left ...

Congestive heart failure is a leading cause of mortality in developed countries. Myocardial hypertrophy resulting from hypertension often precedes heart failure. Understanding the signaling underlying cardiac hypertrophy and failure is of major interest. Here, we identified Fas receptor activation, a classical death signal causing apoptosis via activation of the caspase ...

In a previous retrospective study, long-term treatment of essential hypertensive patients with a slow-release calcium channel blocker resulted in normal resistance artery structure and endothelial function, which did not occur with a beta-blocker. In the present prospective study, 19 previously untreated essential hypertensive patients (aged 47 +/- 2 years, 75% ...

PURPOSE: To report a case of pheochromocytoma exhibiting an increase in systemic vascular resistance index (SVRI) and decreased cardiac index (CI) after use of labetalol. CLINICAL FEATURES: A 36-yr-old male underwent adrenectomy for pheochromocytoma. Midazolam 5 mg, fentanyl 100 microg and labetalol 20 mg were administrated intravenously for premedication upon ...

BACKGROUND: Treatment of essential hypertensive patients with an AT1 angiotensin receptor antagonist has previously resulted in correction of resistance artery structure and endothelial function, whereas in a parallel group treated with the beta-blocker atenolol there was no improvement of altered vascular structure and function. To test the hypothesis that patients ...

Recently, a functional, negatively inotropic, beta(3)-adrenoceptor was characterized in the human heart. Several studies now suggest that this receptor might play an important role in the pathophysiology of heart failure, by counterbalancing the effects of a beta(1)- and beta(2)-stimulation. Therefore, this review summarizes the rationale and effects of beta-adrenergic blockade ...

BACKGROUND: Celiprolol, a newer beta-blocking agent, has been reported to have vasodilatory capacity which may be due to partial beta-2-receptor agonistic activity or to alpha-receptor antagonistic or central sympathoinhibitory effects. METHODS: To more critically assess the physiologic effects of celiprolol, we measured sympathetic nerve activity to muscle (MSNA), forearm blood ...

AIMS: To investigate the effects of selective beta(2)- and selective beta(3)-adrenoceptor (AR) agonists on prostaglandin (PG) E(2)-induced bladder hyperactivity in conscious free-moving rats. METHODS: Female Sprague-Dawley rats were anesthetized for implantation of bladder, intravenous, and intra-arterial catheters. The effects of a beta(3)-AR agonist (CL316,243) on cystometric and cardiovascular parameters were ...

BACKGROUND: Iron deficiency (ID) results in ventricular hypertrophy, believed to involve sympathetic stimulation. We hypothesized that with ID 1) intravenous norepinephrine would alter heart rate (HR) and contractility, 2) abdominal aorta would be larger and more distensible, and 3) the beta-blocker propanolol would reduce hypertrophy. METHODS: 1) 30 CD rats ...

Nebivolol, compared with classical beta-blockers, exerts a high selectivity for beta-adrenergic receptors and also reduces peripheral vascular resistance by modulating nitric oxide (NO) release. This dual mechanism of action leads to effective control of blood pressure at a low degree of beta-blockade and explains the lack of any interference with ...

Central beta-adrenoreceptors may augment sympathetic outflow. We tested the hypothesis that beta-blockade attenuates central sympathetic outflow by inhibiting central adrenoreceptors. We studied 18 healthy controls (4 female, 14 male; age, 26+/-6 years, body mass index, 23+/-3 kg/m(2)). ECG, brachial, and finger arterial blood pressure, muscle sympathetic nerve activity, and respiration ...

Urapidil, a postsynaptic alpha 1 -adrenergic antagonist, has been reported to improve intraoperative hemodynamic stability, although it has never been used to prevent the hemodynamic response of electroconvulsive therapy (ECT). This study was designed to evaluate the clinical effectiveness of urapidil, as an alternative to labetalol, in preventing the hemodynamic ...

OBJECTIVES: The purpose of this study was to determine whether carvedilol's alpha(1)-adrenoceptor antagonism persists during long-term therapy of patients with congestive heart failure (CHF). BACKGROUND: Carvedilol and metoprolol differ in that carvedilol also antagonizes beta(2)- and alpha(1)-adrenoceptors. We hypothesized that in contrast to metoprolol, carvedilol would increase calf vascular conductance ...

We have shown that chronic treatment with carteolol, a non-selective beta-adrenergic receptor antagonist, improved left ventricular (LV) function and survival in an avian model of dilated cardiomyopathy (DCM). The aim of the present study was to compare ex vivo heart function with and without beta-agonist and antagonist challenge. We investigated ...