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Pinsky D J - - 1997
NO alters contractile and relaxant properties of the heart. However, it is not known whether changes in ventricular loading conditions affect cardiac NO synthesis. To understand this potential contractile-relaxant autoregulatory mechanism, production of cardiac NO in response to mechanical stimuli was measured in vivo using a porphyrinic sensor placed in ...
Zahradníková A - - 1997
Nitric oxide (NO) is an important modulator of many physiological processes, including myocardial contractile function. The understanding of how the production of NO in the myocardium is regulated in response to physiological stimuli and pathological processes is evolving rapidly. The main goal of this minireview is to summarize the current ...
Kawada T - - 1997
Although a cardiac microdialysis technique has made it possible to estimate myocardial interstitial norepinephrine (NE) levels, whether such levels reflect the local NE concentration that would regulate ventricular contractility remains unknown. If such levels indicate locally regulating NE concentration, then ventricular contractility should be a unique function of the interstitial ...
Taegtmeyer H - - 1997
The mammalian myocardium meets its high energy needs through the oxidation of a variety of substrates, chiefly fatty acids. This review examines the hypothesis that efficient energy transfer in the heart occurs through a series of moiety-conserved cycles, which makes the heart an obligatory "omnivore." Ischemia results in a transformation ...
Takamura T - - 1997
It is well known that both local and volatile anesthetics depress myocardial functions. This study was performed to evaluate the combined effects of commonly utilized local anesthetics (bupivacaine, mepivacaine, and lidocaine) and a volatile anesthetic (isoflurane) on heart rate and myocardial contractility in an isolated rat working heart preparation using ...
Cain B S - - 1997
BACKGROUND: Hibernating myocardium has traditionally been characterized in terms of systolic dysfunction. METHODS: We describe a case in which a 75-year-old patient with significant coronary artery disease was operated upon for classic constrictive pericarditis. RESULTS: At sternotomy, there was no evidence of pericarditis, but marked diastolic without systolic dysfunction remained. ...
Tuncok Y - - 1997
1. We measured the ability of glucagon and amrinone, used alone and in combination, to improve the myocardial function in a rat isolated heart model of calcium channel blocker (CCB) cardiotoxicity. 2. Verapamil 10(-4) mol consistently decreased heart rate and cardiac contractile force in our Langendorff rat isolated heart preparations. ...
Paulus W J - - 1997
OBJECTIVES: In the present study, we investigated, in transplant recipients, whether L-arginine (L-arg) potentiates the myocardial contractile effects of receptor-mediated coronary endothelial stimulation. Moreover, because inducible nitric oxide synthase (iNOS) is frequently expressed in transplanted myocardium, we also performed intracoronary infusion of L-arg in the absence of receptor-mediated coronary endothelial ...
Yamamoto S - - 1997
BACKGROUND: The positive inotropic response to beta-adrenergic stimulation is attenuated at the isolated myocyte level in heart failure. Nitric oxide (NO) has a negative inotropic effect and attenuates the response to isoproterenol. It has been suggested that NO synthesis is increased in failing myocytes. However, the pathophysiological consequences after induction ...
Lorenz J N - - 1997
To fully utilize the potential of newly developed mouse models with specific genetic mutations, it is necessary to study the functional consequences of genetic manipulation in the fully intact animal. To this end, the purpose of the present study was to develop and validate a methodology for the study of ...
Sirieix D - - 1997
Metabolic acidosis induces a decrease in the developed force of cardiac muscle by affecting every step of the excitation--contraction coupling pathway. Due to transient worsening in intracellular acidosis, the value of administering sodium bicarbonate therapeutically during acute acidosis has been questioned. An alternative therapeutic drug, Tris-hydroxymethyl aminomethane (THAM) has the ...
Mügge A - - 1997
There is accumulating evidence that estrogen replacement therapy protects against the development of coronary atherosclerosis and myocardial infarction in postmenopausal women. The mechanism of this protective effect is uncertain. The purpose of the present study was to determine whether 17 beta-estradiol acutely modifies vascular smooth muscle contractile responses to various ...
Wang J J - - 1997
A novel force transducer was designed to measure the circumferential regional force developed in the ventricular myocardium in vivo. The transducer is composed of a frame, a carrier bar, and a cantilever spring. Two resistance strain gauges embedded on the spring serve as force-sensing elements. The output of a Wheatstone-bridge ...
Marmor A - - 1997
OBJECTIVES: The present study sought to evaluate the prognostic value of contractile reserve measured noninvasively during dobutamine infusion in patients with severe heart failure. BACKGROUND: In patients with severe heart failure there is a great need for objective criteria to define candidates for heart transplantation or intensive medical treatment. Cardiac ...
Guccione J M - - 1997
Active tension developed while cardiac muscle shortens has been studied extensively under afterloaded isotonic or isovelocity conditions. However, these are not true in vivo loading conditions. To obtain more physiological loading, we controlled sarcomere length to follow the time courses that we observed previously in a beating canine left ventricle. ...
Nagaoka H - - 1997
To assess the prognostic significance of myocardial contractile reserve in patients with idiopathic dilated cardiomyopathy (DCM) without overt heart failure (New York Heart Association functional class I or II), seventy-one patients underwent exercise radionuclide angiography in addition to clinical, radiographic, hemodynamic, and echocardiographic evaluations. Myocardial contractile reserve was assessed as ...
Erdmann E - - 1997
Heart failure is associated with pathobiochemical changes that can reduce the responsiveness of the myocardium to positive inotropic agents. We studied the contractile effects of a range of inotropic agents on papillary muscle strips from healthy and failing human hearts. Specimens were obtained from patients with different grades of heart ...
Domanski Michael J. - - 1997
A number of studies that assessed myocardial contractility by noninvasive means have been conducted in the past. However, many of these studies are limited because they assessed the velocity of fiber shortening-afterload relationship at only a single location in the ventricle, thus assuming uniform contractility throughout the ventricle. This is ...
Calò L - - 1997
Bartter's syndrome (BS) is characterized by arterial normohypotension despite biochemical and hormonal abnormalities generally associated with hypertension. An abnormal intracellular calcium homeostasis due to a reduced capacity to increase intracellular calcium has been demonstrated by us in BS and proposed as the main pathophysiological factor of the vascular hyporeactivity in ...
Koss K L - - 1997
Phospholamban is a regulatory phosphoprotein which modulates the active transport of Ca2+ by the cardiac sarcoplasmic reticular Ca(2+)-ATPase enzyme (SERCA2) into the lumen of the sarcoplasmic reticulum. Phospholamban, which is a reversible inhibitor of SERCA2, represses the enzyme's activity, and this inhibition is relieved upon phosphorylation of phospholamban in response ...
Marmor A - - 1996
Functional status in chronic heart failure is evaluated in general by subjective means, such as the New York Heart Association class, or by invasive techniques difficult to use routinely. The aim of this study was to evaluate noninvasively the contractile reserve in cases of heart failure as a means to ...
Biswas S S - - 1996
BACKGROUND: Little is known about preload-dependent cardiac function after brain death (BD) and subsequent graft preservation. METHODS: A validated model of BD in rabbits was developed and myocardial performance was studied after BD induction and 1 hour of subsequent global hypothermic ischemia using a validated rabbit model and an isolated ...
Heusch G - - 1996
Within a few seconds after a sudden reduction of coronary blood flow regional contractile dysfunction ensues. The mechanisms responsible for the rapid reduction in contractile function during acute myocardial ischemia remain unclear, but may involve a rise in inorganic phosphate. When severe ischemia, such as resulting from a sudden and ...
Keaney J F JF - - 1996
Recent in vitro evidence suggests a role for nitric oxide (NO) in the modulation of myocardial contractility. The specific role of NO in the control of cardiac function in vivo, however, remains unclear. We investigated the effect of NO synthase (NOS) inhibition on myocardial contractility in response to beta-adrenergic stimulation ...
Shah A M - - 1996
Endothelial cells within the heart release a number of substances that modulate myocardial contractile function. These agents include nitric oxide, endothelin, prostanoids, adenylpurines, and other substances that have so far been characterized only in bioassay studies. A notable feature of many of these agents is that they influence contractile behavior ...
Hata K - - 1996
BACKGROUND: The effect of cardiotonic drugs with calcium-sensitizing effect (Ca2+ sensitizers) on cardiac mechanoenergetics is not fully understood. Accordingly, the effects of milrinone (a phosphodiesterase inhibitor) and sulmazole (a calcium sensitizer with a phosphodiesterase-inhibiting effect) on left ventricular mechanics and energetics were studied. METHODS AND RESULTS: In excised, cross-circulated canine ...
Padrini R - - 1996
The aim of the study was to compare the contractile response to ryanodine of human heart preparations taken from right and left ventricles of patients affected by idiopathic (IDCM) and secondary (SCM) end-stage dilated cardiomyopathies. Right and left ventricle myocardial strips were obtained from hearts of patients undergoing orthotopic heart ...
Upton R N - - 1996
The myocardial kinetics and dynamics of thiopental (750 mg over 2 min) were examined in chronically instrumented sheep (five studies in four sheep). The myocardial kinetics were studied by simultaneous rapid sampling of arterial and coronary sinus blood for 30 min. The myocardial kinetics for four of the five studies ...
Pogátsa G - - 1996
Since the first publication of the University Group Diabetes Programme in 1970 the possible deleterious cardiovascular effects of certain hypoglycaemic sulphonylurea products has been well known. In contrast, international knowledge of the advantageous cardiovascular effects of certain sulphonylurea compounds became available recently. Glibenclamide decreases the incidence of fatal myocardial infarction ...
Davidson S B - - 1996
OBJECTIVE: To determine whether sepsis, with or without thyroid hormonal augmentation, induces myocardial tolerance to an oxidant challenge. DESIGN: A prospective, randomized, controlled animal trial. SETTING: University research laboratory. SUBJECTS: Twenty male Sprague-Dawley rats. INTERVENTIONS: After anesthesia, animals underwent cecal ligation and puncture, with or without 3,5,3'-triiodothyronine replacement (3 ng/hr), ...
Tran L - - 1996
Unlike in adult heart, embryonic myocardium works at low PO2 and depends preferentially on glucose. Therefore, activity of the embryonic heart during anoxia and reoxygenation should be particularly affected by changes in glucose availability. Hearts excised from 4-d-old chick embryos were submitted in vitro to strictly controlled anoxia-reoxygenation transitions at ...
Mazer C D - - 1996
We examined the impact of alkali therapy on myocardial contractility in a model of myocardial ischemia in dogs using direct measurements of myocardial contractile function. Myocardial ischemia in the left anterior descending (LAD) artery territory was induced using a perfusion circuit from the internal carotid artery to the LAD artery. ...
Imamura M - - 1996
Antidromic stimulation of cardiac sensory C fibers releases calcitonin gene-related peptide (CGRP), which increases heart rate, contractility, and coronary flow. C-fiber endings are closely associated with mast cells, and CGRP may release mast-cell histamine. Because prejunctional histamine H3-receptors inhibit transmitter release from autonomic nerves, we tested the hypothesis that H3-receptors ...
Goddard C M - - 1996
Decreased ventricular contractility during sepsis lasts much longer than the half-lives of inflammatory mediators that have been suggested to be myocardial depressant factors. Our hypothesis is that blood-borne factors may also cause myocardial structural changes, including damage and death of myocytes, associated with decreased ventricular contractility. We tested this hypothesis ...
Tian R - - 1996
To study the contribution of myocardial energy reserve to the deterioration of cardiac function during the development of heart failure, we defined energy reserve via the creatine kinase (CK) reaction and the isovolumic contractile performance in hearts of cardiomyopathic hamsters at the ages of 1.5, 4, 17, 30 and 43 ...
Barendregt D S - - 1996
The objective of this study was to evaluate the effect of the tine shape of 3 different periodontal probes. One tapered, one parallel-sided and one WHO-probe tine, each with a diameter of 0.5 mm at the tip, were mounted in hinged handles exerting a constant probing force (Brodontic). The handles ...
McMahon W S - - 1996
OBJECTIVES: Comparison of the effects of supraventricular tachycardia-induced dilated cardiomyopathy on left and right ventricular isolated myocyte geometry and function. BACKGROUND: Chronic ventricular tachycardia and supraventricular tachycardia cause left ventricular dilation and dysfunction in humans. However, it is unknown whether supraventricular tachycardia-induced dilated cardiomyopathy is a homogenous process for both ...
Prasad K - - 1996
We investigated the effects of chronic volume overload in the absence or presence of vitamin E supplements on the cardiac function and contractility, cardiac malondialdehyde (MDA)--a lipid peroxidation product--cardiac antioxidant enzyme activity and antioxidant reserve in canine model. The dogs were divided into three groups of seven dogs each: group ...
Tanonaka K - - 1996
The present study was undertaken to determine whether myocardial energy or ion levels are related to oxygen-replenishment-induced recovery of cardiac contractile force after hypoxia. Isolated rat hearts were perfused for 3 to 40 min under hypoxic conditions, followed by 45 min of reoxygenation. Hypoxia induced a cessation of cardiac contractile ...
Naito J - - 1996
Influence of hemodynamic changes in preload, afterload and contractility on myocardial integrated backscatter (IB) was studied in 26 adult mongrel dogs by measuring myocardial IB calibrated with the backscatter from the blood during volume infusion (preload alteration), during aortic constriction (afterload alteration), and during dobutamine or propranolol infusion (contractility alteration). ...
Pihkala J - - 1996
Cardiotoxicity is a potential adverse effect of anthracycline (A) therapy. Radiotherapy (XRT) may also cause a variety of cardiac complications. The purpose of the present study was to evaluate these cardiac side-effects in children and adolescents treated for cancer. We assessed the cardiac status of 91 patients, divided into three ...
Dhalla N S - - 1996
Occlusion of a coronary artery results in myocardial ischemia and subsequent myocardial infarction. Whenever the infarct size is more than 30% of the ventricular wall, the remaining myocardium attempts to compensate for the loss of muscle mass by changing the size and shape of cardiocytes in addition to developing cardiac ...
Dorman B H - - 1995
The direct and interactive effects of phosphodiesterase inhibition (PDEI) and beta-adrenergic receptor (beta AR) stimulation on isolated myocyte contractile function were examined after hypothermic, hyperkalemic, cardioplegic arrest (HHCA) and under normothermic conditions. Left ventricular (LV) myocytes were isolated from porcine hearts and myocyte contractile function was measured under normothermic conditions ...
Keller R S - - 1995
Nitric oxide has been implicated in the regulation of cardiac contractile function as well as the depressed myocardial contractility associated with sepsis and endotoxemia. We examined the effects of nitric oxide synthase (NOS) inhibitors and a nitric oxide generator on contractile responses of left atrial preparations and ventricular myocytes isolated ...
White M - - 1995
BACKGROUND: Ten percent to 20% of potential cardiac donors with brain injury and no previous cardiac history have myocardial dysfunction. We assessed components of the beta-receptor-G-protein-adenylyl cyclase complex as well as the contractile response in 10 explanted acutely failing human hearts (donor heart dysfunction [DHD]) and compared the results with ...
Ross J J - - 1995
This article briefly reviews recent experimental studies which show that beta-adrenergic receptor stimulation produces an important enhancement of the force-frequency relation on myocardial contractility. The basic property of the force-frequency effect to progressively enhance myocardial contractility as heart rate increases is augmented at each level of increasing adrenergic stimulation. This ...
Evangelou A - - 1995
PAF-acether is a phospholipid synthesized by most animal tissues and exerting a strong decrease on the heart's contractile force and coronary flow. PAF-acether (10(-9) and 10(-10)M) was administered to isolated guinea pig hearts perfused via the Langendorff apparatus with Chenoweth solution. Zinc (1.5 microM) is known to benefit heart function ...
Cargill R I - - 1995
STUDY OBJECTIVE: Although some of the cardiovascular responses to hypoxemia are well described, effects on myocardial contractility have not been defined. Such effects are readily assessed by noninvasive techniques and we have therefore evaluated Doppler-phonocardiographic parameters of systolic left ventricular contractility in normal humans rendered hypoxemic. DESIGN: Eight healthy male ...
Mori T - - 1995
1. The aim of the present study was to determine whether antianginal efficacy of semotiadil fumarate (SD-3211), a structurally novel calcium antagonist, is distinct from those of diltiazem, nifedipine and nisoldipine. 2. First, the duration of the inhibitory effects of semotiadil was compared with that of other Ca2+ antagonists in ...
Hare J M - - 1995
Nitric oxide (NO), produced by either constitutive or inducible isoforms of NO synthase (cNOS or iNOS), influences myocardial inotropic and chronotropic responses. This pathway has been studied using NO donors or NOS inhibitors or by immune-mediated stimulation of iNOS. Although inhibition of constitutive NO activity in the heart does not ...
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