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Results 251 - 300 of 518
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Sabir Ian N - - 2008
The experiments investigated the applicability of two established criteria for arrhythmogenicity in Scn5a+/Delta and Scn5a+/- murine hearts modelling the congenital long QT syndrome type 3 (LQT3) and the Brugada syndrome (BrS). Monophasic action potentials (APs) recorded during extrasystolic stimulation procedures from Langendorff-perfused control hearts and hearts treated with flecainide (1 ...
Filas Benjamen A - - 2007
Optical coherence tomography (OCT) was used to investigate morphogenesis of the embryonic chick heart during the first phase of looping (c-looping), as the heart bends and twists into a c-shaped tube. The present study focuses on the morphomechanical effects of the splanchnopleure (SPL), a membrane that has been shown to ...
Sabir Ian N - - 2008
Alternans and arrhythmogenicity were studied in hypokalaemic (3.0 mM K(+)) Langendorff-perfused murine hearts paced at high rates. Epicardial and endocardial monophasic action potentials were recorded and durations quantified at 90% repolarization. Alternans and arrhythmia occurred in hypokalaemic, but not normokalaemic (5.2 mM K(+)) hearts (P<0.01): this was prevented by treatment ...
Ago Tetsuro - - 2007
Excessive reactive oxygen species (ROS) play an important role in the development of cardiac hypertrophy. In contrast, antioxidants scavenge ROS, thereby maintaining the reduced environment of cells and inhibiting hypertrophy in the heart. Thioredoxin1 (Trx1) not only functions as a major antioxidant in the heart but also interacts with important ...
Ruiz-Capillas C - - 2007
Biogenic amine formation and microbiota evolution were assessed in Spanish dry-cured "chorizo" sausage treated with high-pressure (HP) and kept at 2°C. High-pressures did not affect (p<0.05) pH or water activity (a(w)). However, HP treatment did significantly reduce the level of lactic acid bacteria, by <1 logarithmic unit. Microorganism levels remained ...
Sato Yuichi - - 2007
Double chambered right ventricle (DCRV) is a rare form of congenital heart disease in which the right ventricle is divided into a high-pressure inlet site and a low-pressure outlet site by anomalous muscle bands. Whole heart magnetic resonance imaging (MRI) which depicts 3-dimensional anatomy of the heart and coronary arteries ...
Cobb Alexander R - - 2007
Freeze-thaw cycles pose a major physiological challenge for all temperate perennial plants, but monocotyledonous vines face a still greater risk because their few large vessels are especially susceptible to embolism and are not replaced by secondary growth. The genus Smilax is particularly remarkable because it is widespread in the tropics ...
Milberg Peter - - 2007
BACKGROUND: Numerous noncardiovascular drugs prolong repolarization and thereby increase the risk for patients to develop life-threatening tachyarrhythmias of the torsade de pointes (TdP) type. The development of TdP is an individual, patient-specific response to a repolarization-prolonging drug, depending on the repolarization reserve. The aim of the present study was to ...
Karsdorp Petra A - - 2007
The present study was aimed at clarifying whether preattentive processing of heart cues results in biased perception of heart sensations in patients with congenital heart disease (ConHD) who are also highly trait anxious. Twenty-six patients with ConHD and 22 healthy participants categorized heart-related (heart rate) or neutral sensations (constant vibration) ...
Wu Jiun-Yan - - 2007
Electromuscular incapacitating devices (EMDs), such as Tasers, deliver high current, short duration pulses that cause muscular contractions and temporarily incapacitate the human subject. Some reports suggest that EMDs can kill. To help answer the question, "Can the EMD directly cause ventricular fibrillation (VF)?", ten tests were conducted to measure the ...
Zhu Xiaocheng - - 2007
The major developments in pig-to-non-human primate heart xenotransplantation during the past 20 years are summarized, largely through the experience of one investigator. Genetic modifications to organ-source pigs have been important steps in increasing heart xenograft survival from a few minutes in 1986 to 2 to 6 months in 2005.
Supavititpatana Thawatchai - - 2007
Ostrich meat sausages (yor) were subjected to ultra-high pressures of 300, 500 and 700MPa for 40 and 60min at 40 and 60°C. Subsequently the physical properties of the products, colour, released and expressible water, gel strength and stress relaxation as well as their thermal characteristics (by differential scanning calorimeter, DSC) ...
Linask Kersti K - - 2007
Over the past 10 years, key genes involved in specification of left-right laterality pathways in the embryo have been defined. The read-out for misexpression of laterality genes is usually the direction of heart looping. The question of how dextral looping direction occurred mechanistically and how the heart tube bends remains ...
van Wijk Bram - - 2007
Bone morphogenetic proteins (BMP) are involved in the regulation of a plethora of processes underlying cardiovascular development. This review summarizes the effects of BMP and the signaling pathways that regulate the differentiation of cardiomyocytes from mesoderm in the heart-forming region and at the distal borders of the heart tube from ...
Hoyer Kirsten K NMR Laboratory for Physiological Chemistry, Brigham and Women's Hospital, Harvard Medical School, 221 Longwood Ave., BLI 247, Boston, MA 02115, USA. - - 2007
Cardiac-specific transgenesis in the mouse is widely used to study the basic biology and chemistry of the heart and to model human cardiovascular disease. A fundamental difference between mouse and human hearts is the background motor protein: mouse hearts contain predominantly the alphaalpha-myosin heavy chain (MyHC) isozyme while human hearts ...
Bisping Egbert - - 2006
An important event in the pathogenesis of heart failure is the development of pathological cardiac hypertrophy. In cultured cardiomyocytes, the transcription factor Gata4 is required for agonist-induced hypertrophy. We hypothesized that, in the intact organism, Gata4 is an important regulator of postnatal heart function and of the hypertrophic response of ...
Bilir Ayten - - 2006
OBJECTIVE: To compare the inotropic and chronotropic effects of ropivacaine and bupivacaine in an isolated, spontaneously beating rat heart, and to determine the reversal effects of dopexamine on these effects. METHODS: The study was conducted at the Department of Physiology, Medical Faculty, Osmangazi University, Eskisehir, Turkey in November 2001. Fifty ...
Valderrábano Miguel - - 2006
BACKGROUND: During development, AV conduction switches from base-to-apex to apex-to-base conduction after emergence of the conduction system. We hypothesize that after this transition, the bulk of the AV ring, although no longer required for AV conduction, remains transiently able to conduct, providing a potential arrhythmia substrate. We studied AV conduction ...
Gupte Sachin A - - 2006
In the failing heart, NADPH oxidase and uncoupled NO synthase utilize cytosolic NADPH to form superoxide. NADPH is supplied principally by the pentose phosphate pathway, whose rate-limiting enzyme is glucose 6-phosphate dehydrogenase (G6PD). Therefore, we hypothesized that cardiac G6PD activation drives part of the excessive superoxide production implicated in the ...
Perrino Cinzia - - 2006
Human heart failure is a complex clinical syndrome characterized by extensive abnormalities in the beta-adrenergic receptor (betaAR) system. Normalization of betaAR signalling consistently ameliorates cardiac dysfunction and survival in heart failure, suggesting that betaAR dysfunction may be intrinsically linked to the deterioration of cardiac performance. Agonist-dependent phosphorylation of betaARs by ...
Wang Yanggan - - 2006
The early phase of action potential (AP) repolarization is critical to impulse conduction in the heart because it provides current for charging electrically coupled cells. In the present study we tested the impact of heart failure-associated electrical remodeling on AP propagation. Subepicardial, midmyocardial, and subendocardial myocytes were enzymatically dissociated from ...
Satpathy Chhabi - - 2006
Diastolic heart failure occurs when signs and symptoms of heart failure are present but left ventricular systolic function is preserved (i.e., ejection fraction greater than 45 percent). The incidence of diastolic heart failure increases with age; therefore, 50 percent of older patients with heart failure may have isolated diastolic dysfunction. ...
Augustus Ayanna S - - 2006
Long-chain fatty acids (FAs) are the predominant energy substrate utilized by the adult heart. The heart can utilize unesterified FA bound to albumin or FA obtained from lipolysis of lipoprotein-bound triglyceride (TG). We used heart-specific lipoprotein lipase knock-out mice (hLpL0) to test whether these two sources of FA are interchangeable ...
Meijler Frits L - - 2006
Scaling can be defined as the adjustment of a structure, a function, or an organ to the size of the mammalian body. An example is the size of the heart in relation to the size of the body. The duration of the PR interval on the electrocardiogram (atrioventricular delay) in ...
Taber Larry A - - 2006
During early embryogenesis, the heart is a single, relatively straight tube which bends and twists (loops) rightward to create the basic plan of the mature heart. Despite intensive study for many decades, the biophysical mechanisms which drive and regulate cardiac looping have remained poorly understood. This review discusses, from a ...
Vasconcelos C M L - - 2006
This work aims to describe some electrophysiological changes promoted by the aqueous extract (AEx) from Averrhoa carambola leaves in guinea pig heart. The experiments were carried out on isolated heart or on right atrium-ventricle preparations. In 6 hearts, the extract induced many kinds of atrioventricular blocks (1st, 2nd, and 3rd ...
Anversa Piero - - 2005
This review questions the old paradigm that describes the heart as a post-mitotic organ and introduces the notion of the heart as a self-renewing organ regulated by a compartment of multipotent cardiac stem cells (CSCs) capable of regenerating myocytes and coronary vessels throughout life. Because of this dramatic change in ...
McQueen Alfred P - - 2005
Diabetics have worse outcomes than nondiabetics after a variety of cardiac insults. We tested the hypothesis that impaired insulin receptor signaling in myocytes worsens cardiac remodeling and function following injury, even in the absence of hyperglycemia. Mice with cardiomyocyte-restricted knock out of the insulin receptor (CIRKO) and wild type (WT) ...
Amir Gabriel - - 2005
BACKGROUND: Freeze-tolerant fish survive sub-zero temperatures by non-colligatively lowering the freezing temperature of their body fluids using anti-freeze proteins (AFPs). We sought to evaluate and compare the effects of prolonged sub-zero cryopreservation of transplanted rat hearts using AFP I or AFP III. METHODS: Two heterotopic rat heart transplantation protocols were ...
Csont Tamás - - 2005
Pro-inflammatory cytokines have been shown to depress myocardial mechanical function by enhancing peroxynitrite generation in the heart. The contribution of NO synthesized by different NOS isoforms, as well as the contribution of superoxide to this mechanism are still not clear. Isolated working hearts of iNOS(-/-) and wildtype mice were perfused ...
Linask Kersti K - - 2005
During heart organogenesis, the spatiotemporal organization of the extracellular matrix (ECM) undergoes significant remodeling. Because matrix metalloproteinases (MMPs) are known to be key regulators of cell-matrix interactions, we analyzed the role(s) of MMPs, and specifically MMP-2, in early heart development. Both MMP-2 neutralizing antibody and the broad-spectrum MMP inhibitor Ilomastat ...
Antkiewicz Dagmara S - - 2005
The zebrafish (Danio rerio) has become an attractive vertebrate model for studying developmental processes, and is emerging as a model system for studying the mechanisms by which toxic compounds perturb normal development. When exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) shortly after fertilization, zebrafish embryos exhibit pericardial edema and reduced blood flow by ...
Opitz Christiane A - - 2005
Many sarcomeric proteins in the myocardium alter their isoform pattern during perinatal development to adjust to the intensified pump function of the postnatal heart. These changes also involve the giant protein titin/connectin. Here we show by low-percentage polyacrylamide-gel electrophoresis that developmentally regulated switching of cardiac titin/connectin size occurs in the ...
Huang Ran - - 2005
Effects of heart failure on the mechanical function of the heart are difficult to assess experimentally, yet they pose a serious physiological challenge. By integrating modified cellular action potential model based on experimental data of heart failure with modified Hunter-McCulloch-ter Keurs (HMT) mechanical heart cell model, an electromechanical cardiac cell ...
Arce-Fonseca Minerva - - 2005
Destruction of heart tissue in chronic chagasic cardiopathy may be caused by autoimmune recognition of heart tissue. Indirect evidence suggests that there is antigenic cross-reactivity between Trypanosoma cruzi and heart tissue. The objective of this study was to determine whether seric autoantibodies against atrio-ventricular (AV) node and sinus auricular node ...
Zhang Yu - - 2005
This paper presents simulation study of the action potential waveforms of different ventricular cell types based on experimental studies of transmural electrophysiological heterogeneities in control and failing human hearts. The results show that prolonged action potential duration (APD) and APD rate-adaptation are markedly transmural heterogeneous in heart failure than those ...
Xiao Chun-Yang - - 2005
Oxidant stress-induced activation of poly(ADP-ribose) polymerase (PARP) plays a role in the pathogenesis of various cardiovascular diseases. We have now investigated the role of PARP in the process of cardiac remodeling and heart failure in a mouse model of heart failure induced by transverse aortic constriction (banding). The catalytic activity ...
Muniz-Junqueira Maria Imaculada - - 2004
We evaluated the in vitro phagocytic function and the production of microbicidal oxygen radicals by monocytes and neutrophils of 9 Chagas' heart disease subjects with heart failure and 9 without the syndrome in comparison with 11 healthy subjects, by assessing phagocytosis of Saccharomyces cerevisiae and NBT reduction by peripheral blood ...
Buckberg Gerald - - 2004
The Reviews report will establish guidelines that underlie why the "restoration concept" may develop a paradigm shift in thinking, by addressing the geometric underpinnings of heart failure and their evolution. This presentation will (a) show that the underlying structure of the failing dilated heart involves a cardiac architectural change from ...
Fogle Crystelle C - - 2004
INTRODUCTION: Early recognition of the signs and symptoms of a heart attack can lead to reduced morbidity and mortality. METHODS: A workplace intervention was conducted among 523 Montana state health department employees in 2003 to increase awareness of the signs and symptoms of heart attack and the need to use ...
Amir Gabriel - - 2004
The purpose of the present study was to evaluate whether AFPs protect the heart from freezing and improve survival and viability in subzero cryopreservation. Hearts were subject to 5 preservation protocols; University of Wisconsin solution (UW) at 4 degrees C, UW at -1.3 degrees C without nucleation, UW at -1.3 ...
Phoon Colin K L - - 2004
Gene targeting in the mouse has become a standard approach, yielding important new insights into the genetic factors underlying cardiovascular development and disease. However, we still have very limited understanding of how mutations affect developing cardiovascular function, and few studies have been performed to measure altered physiological parameters in mouse ...
Männer Jörg - - 2004
The internal organs of vertebrates show specific anatomical left-right asymmetries. The embryonic heart is the first organ to develop such asymmetries during a process called dextro-looping. Thereby the initially straight heart tube curves toward its original ventral side and the resulting bend becomes displaced toward the right side of the ...
Abdulla R - - 2004
During the first 20 days of development, the human embryo has no cardiovascular structure. Over the next month, the heart and great vessels complete their development and look very much like they will at full gestation. This amazing process transforms isolated angiogenic cell islets into a complex, four-chambered structure. During ...
Ruan Yan-Fei - - 2004
BACKGROUND: Torsade de pointes (TdP) is a form of polymorphic ventricular tachycardia featuring prolonged QT intervals. Female gender is associated with an increased risk of TdP. However, the causes of the sex difference in risk are poorly understood. Recently, transmural dispersion of repolarization (TDR) has been implicated in the genesis ...
Sperry John S - - 2004
A model predicted pit and vessel conductivity, the air-seed pressure for cavitation, and the implosion pressure causing vessel collapse. Predictions were based on measurements from 27 angiosperm species with circular bordered pits and air-seed pressures of 0.2-11.3 MPa. Vessel implosion pressure exceeded air-seed pressure by a safety factor of 1.8 ...
Ward Kathleen - - 2003
The contribution of mitochondria to water-macromolecule proton magnetization transfer (MT) was evaluated in porcine heart tissue. An examination of isolated mitochondria in suspension, at the same concentration as found in heart tissue, revealed MT effects very similar in magnitude and bandwidth to those in intact heart tissue. Disruption of the ...
McMullen Julie R - - 2004
Insulin-like growth factor 1 (IGF1) was considered a potential candidate for the treatment of heart failure. However, some animal studies and clinical trials have questioned whether elevating IGF1 chronically is beneficial. Secondary effects of increased serum IGF1 levels on other tissues may explain these unfavorable results. The aim of the ...
Mispelon Melissa - - 2003
Here we report the effect of a nonpeptide, benzethonium chloride (bztc), on Drosophila melanogaster larval, pupal, and adult heart rates in vivo. Benzethonium chloride reduced the frequency of spontaneous contractions in the D. melanogaster pupal heart, but not in the larval heart or the adult heart as measured in noninvasive ...
Wenning Angela - - 2004
Two tubular hearts propel blood through the closed circulatory system of the medicinal leech. The hearts are myogenic but are driven by a centrally generated motor pattern that controls heart rate and intersegmental coordination. In two consecutive papers, we address the question of how the motor pattern is translated into ...
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