Ursula Ravens

Acute atrial tachyarrhythmia induces angiotensin II type 1 receptor-mediated oxidative stress and microvascular flow abnormalities in the ventricles (2009)

Goette, Andreas, Bukowska, Alicja, Dobrev, Dobromir, Pfeiffenberger, Jan, Morawietz, Henning, Strugala, Denis, ...

Aims Patients with paroxysmal atrial fibrillation (AF) often present with typical angina pectoris and mildly elevated levels of cardiac troponin (non ST-segment elevation myocardial infarction)...

Impaired vascular function in small resistance arteries of LOX-1 overexpressing mice on high-fat diet (2009)

Eichhorn, Birgit, Muller, Gregor, Leuner, Anja, Sawamura, Tatsuya, Ravens, Ursula, Morawietz, Henning

Aims LOX-1 is a major vascular receptor for oxidized low-density lipoprotein (oxLDL). In this study, we analysed the impact of LOX-1 overexpression and high dietary fat intake on vascular function in...

The Registry of the German Competence NETwork on Atrial Fibrillation: patient characteristics and initial management (2009)

Nabauer, Michael, Gerth, Andrea, Limbourg, Tobias, Schneider, Steffen, Oeff, Michael, Kirchhof, Paulus, ...

Aims The aim of this study was to describe the characteristics of patients with atrial fibrillation (AF) enrolled in the Central Registry of the German Competence NETwork on Atrial Fibrillation...

Changes in IK,ACh single-channel activity with atrial tachycardia remodelling in canine atrial cardiomyocytes (2008)

Voigt, Niels, Maguy, Ange, Yeh, Yung-Hsin, Qi, Xiaoyan, Ravens, Ursula, Dobrev, Dobromir, ...

Aims Although atrial tachycardia (AT) remodelling promotes agonist-independent, constitutively active, acetylcholine-regulated K+-current (IK,ACh) that increases susceptibility to atrial fibrillation...

Role of potassium currents in cardiac arrhythmias (2008)

Ravens, Ursula, Cerbai, Elisabetta

Abnormal excitability of myocardial cells may give rise to ectopic beats and initiate re-entry around an anatomical or functional obstacle. As K+ currents control the repolarization process of the...

Outcome parameters for trials in atrial fibrillation: Recommendations from a consensus conference organized by the German Atrial Fibrillation Competence NETwork and the European Heart Rhythm Association (2007)

Kirchhof, Paulus, Auricchio, Angelo, Bax, Jeroen, Crijns, Harry, Camm, John, Diener, Hans-Christoph, ...

Atrial fibrillation (AF), the most common atrial arrhythmia, has a complex aetiology and causes relevant morbidity and mortality due to different mechanisms, including but not limited to stroke,...

Differential phosphorylation-dependent regulation of constitutively active and muscarinic receptor-activated IK,ACh channels in patients with chronic atrial fibrillation (2007)

Voigt, Niels, Friedrich, Adina, Bock, Manja, Wettwer, Erich, Christ, Torsten, Knaut, Michael, ...

Objective: In chronic atrial fibrillation (cAF) the potassium current IK,ACh develops agonist-independent constitutive activity. We hypothesized that abnormal phosphorylation-dependent regulation...

Changes in IK,ACh single channel activity with atrial tachycardia remodeling in canine atrial cardiomyocytes (2007)

Voigt, Niels, Maguy, Ange, Yeh, Yung-Hsin, Qi, Xiaoyan, Ravens, Ursula, Dobrev, Dobromir, ...

Aims Although atrial tachycardia (AT) remodelling promotes agonist-independent, constitutively active, acetylcholine-regulated K+-current (IK,ACh) that increases susceptibility to atrial fibrillation...

Changes in IK,ACh single-channel activity with atrial tachycardia remodelling in canine atrial cardiomyocytes (2007)

Voigt, Niels, Maguy, Ange, Yeh, Yung-Hsin, Qi, Xiaoyan, Ravens, Ursula, Dobrev, Dobromir, ...

Aims Although atrial tachycardia (AT) remodelling promotes agonist-independent, constitutively active, acetylcholine-regulated K+-current (IK,ACh) that increases susceptibility to atrial fibrillation...

Carvedilol blocks beta(2)- more than beta(1)-adrenoceptors in human heart (2006)

Molenaar, Peter, Christ, Torsten, Ravens, Ursula, Kaumann, Alberto

Objective: To understand the basis of the effectiveness of carvedilol in heart failure by determining its specific properties at human heart and beta(2)-adrenoceptors. Methods: The positive inotropic...

Carvedilol blocks beta(2)- more than beta(1)-adrenoceptors in human heart (2006)

Molenaar, Peter, Christ, Torsten, Ravens, Ursula, Kaumann, Alberto

Objective: To understand the basis of the effectiveness of carvedilol in heart failure by determining its specific properties at human heart and beta(2)-adrenoceptors. Methods: The positive inotropic...

Carvedilol blocks {beta}2- more than {beta}1-adrenoceptors in human heart (2006)

Molenaar, Peter, Christ, Torsten, Ravens, Ursula, Kaumann, Alberto

Objective: To understand the basis of the effectiveness of carvedilol in heart failure by determining its specific properties at human heart β1- and β2-adrenoceptors. Methods: The positive...

Functional modulation of the transient outward current Ito by KCNE {beta}-subunits and regional distribution in human non-failing and failing hearts (2006)

Radicke, Susanne, Cotella, Diego, Graf, Eva Maria, Banse, Ulrich, Jost, Norbert, Varró, András, ...

Objectives The function of Kv4.3 (KCND3) channels, which underlie the transient outward current Ito in human heart, can be modulated by several accessory subunits such as KChIP2 and KCNE1–KCNE5....

Human inward rectifier potassium channels in chronic and postoperative atrial fibrillation (2002)

Dobrev, Dobromir, Wettwer, Erich, Kortner, Ariane, Knaut, Michael, Schüler, Stephan, Ravens, Ursula

Objective: We showed recently that the 825T allele of the G-protein β3-subunit C825T polymorphism is associated with large inward rectifier K+ currents IK1 but low acetylcholine-activated K+ current...

L-type calcium current and contractility in ventricular myocytes from mice overexpressing the cardiac {beta}2-adrenoceptor (1999)

Heubach, Jürgen F, Trebeß, Ina, Wettwer, Erich, Himmel, Herbert M, Michel, Martin C, Kaumann, Alberto J, ...

Objectives: The reported increase in basal activity of hearts from transgenic mice (TG4) overexpressing the human β2-adrenoceptor (β2-AR) was explained by spontaneously active β2-ARs that...

Characterization of excitation-contraction coupling in conscious dogs with pacing-induced heart failure (1998)

Neumann, Till, Ravens, Ursula, Heusch, Gerd

Objective: In isolated cardiac preparations of non-failing hearts from different species, including man, there is a positive force–frequency relation which is reversed into a negative relation in...

Tachycardia-induced failure alters contractile properties of canine ventricular myocytes (1996)

Ravens, Ursula, Davia, Kerry, Davies, Crispin H., O'Gara, Peter, Drake-Holland, Angela J., Hynd, John W., ...

Objective Rapid cardiac pacing has been used as a model for experimentally-induced cardiomyopathy. However, its relevance to human heart failure is not clear at present because little is known about...

Transient outward current in human and rat ventricular myocytes (1993)

Wettwer, Erich, Amos, Gregory, Gath, Jennifer, Zerkowski, Hans-Reinhard, Reidemeister, Jürgen-Christoph, Ravens, Ursula

Objective: The aim was to investigate transient outward currents (Ito) in single myocytes isolated from human heart muscle specimens which were obtained either from patients in terminal heart failure...

Identification and characterization of G beta 3s2, a novel splice variant of the G-protein beta 3 subunit.

Rosskopf, Dieter, Manthey, Iris, Habich, Christiane, Kielbik, Marzena, Eisenhardt, Andreas, Nikula, Christiane, ...

The T-allele of a polymorphism (C825T) in the gene for the G-protein beta 3 subunit (GNB3) is associated with cardiovascular and metabolic disorders, distinct cellular features and altered drug...

Expression and function of dipeptidyl-aminopeptidase-like protein 6 as a putative β-subunit of human cardiac transient outward current encoded by Kv4.3

Radicke, Susanne, Cotella, Diego, Graf, Eva Maria, Ravens, Ursula, Wettwer, Erich

Dipeptidyl-aminopeptidase-like protein 6 (DPPX) was recently shown in the brain to modulate the kinetics of transient A-type currents by accelerating inactivation and recovery from inactivation....

Electrophysiological properties of human mesenchymal stem cells

Heubach, Jürgen F, Graf, Eva M, Leutheuser, Judith, Bock, Manja, Balana, Bartosz, Zahanich, Ihor, ...

Human mesenchymal stem cells (hMSC) have gained considerable interest due to their potential use for cell replacement therapy and tissue engineering. One strategy is to differentiate these bone...

Identification and characterization of G beta 3s2, a novel splice variant of the G-protein beta 3 subunit.

Rosskopf, Dieter, Manthey, Iris, Habich, Christiane, Kielbik, Marzena, Eisenhardt, Andreas, Nikula, Christiane, ...

The T-allele of a polymorphism (C825T) in the gene for the G-protein beta 3 subunit (GNB3) is associated with cardiovascular and metabolic disorders, distinct cellular features and altered drug...

Expression and function of dipeptidyl-aminopeptidase-like protein 6 as a putative β-subunit of human cardiac transient outward current encoded by Kv4.3

Radicke, Susanne, Cotella, Diego, Graf, Eva Maria, Ravens, Ursula, Wettwer, Erich

Dipeptidyl-aminopeptidase-like protein 6 (DPPX) was recently shown in the brain to modulate the kinetics of transient A-type currents by accelerating inactivation and recovery from inactivation....

Electrophysiological properties of human mesenchymal stem cells

Heubach, Jürgen F, Graf, Eva M, Leutheuser, Judith, Bock, Manja, Balana, Bartosz, Zahanich, Ihor, ...

Human mesenchymal stem cells (hMSC) have gained considerable interest due to their potential use for cell replacement therapy and tissue engineering. One strategy is to differentiate these bone...

The effects of verapamil and diltiazem on N-, P- and Q-type calcium channels mediating dopamine release in rat striatum

Dobrev, Dobromir, Milde, Alexander S, Andreas, Klaus, Ravens, Ursula

The putative inhibitory effects of verapamil and diltiazem on neuronal non-L-type Ca2+ channels were studied by investigating their effects on either K+- or veratridine-evoked [3H]-dopamine ([3H]-DA)...

Mechanism of block by tedisamil of transient outward current in human ventricular subepicardial myocytes

Wettwer, Erich, Himmel, Herbert M, Amos, Gregory J, Li, Qi, Metzger, Franz, Ravens, Ursula

Tedisamil is a new antiarrhythmic drug with predominant class III action. The aim of the present study was to investigate the blocking pattern of the compound on the transient outward current (Ito)...

The effect of Gi-protein inactivation on basal, and β1- and β2AR-stimulated contraction of myocytes from transgenic mice overexpressing the β2-adrenoceptor

Gong, Haibin, Adamson, Dawn L, Ranu, Hardeep K, Koch, Walter J, Heubach, Jürgen F, Ravens, Ursula, ...

The atria and ventricles of transgenic mice (TGβ2) with cardiac overexpression of the human β2-adrenoceptor (β2AR) were initially reported to show maximum contractility in the absence of β-AR...

Murine ventricular L-type Ca2+ current is enhanced by zinterol via β1-adrenoceptors, and is reduced in TG4 mice overexpressing the human β2-adrenoceptor

Heubach, Jürgen F, Graf, Eva M, Molenaar, Peter, Jäger, Andreas, Schröder, Frank, Herzig, Stefan, ...

The functional coupling of β2-adrenoceptors (β2-ARs) to murine L-type Ca2+ current (ICa(L)) was investigated with two different approaches. The β2-AR signalling cascade was activated either with...

Physiological antagonism between ventricular β1-adrenoceptors and α1-adrenoceptors but no evidence for β2- and β3-adrenoceptor function in murine heart

Heubach, Jürgen F, Rau, Thomas, Eschenhagen, Thomas, Ravens, Ursula, Kaumann, Alberto J

Murine left atrium lacks inotropic β2-adrenoceptor function. We investigated whether β2-adrenoceptors are involved in the cardiostimulant effects of (−)-adrenaline on spontaneously beating right...

Pharmacodynamics of propiverine and three of its main metabolites on detrusor contraction

Wuest, Melinda, Hecht, Juliane, Christ, Torsten, Braeter, Manfred, Schoeberl, Christian, Hakenberg, Oliver W, ...

Besides its antimuscarinic effects, propiverine may possess an additional mode of action. We compared the effects of propiverine, three of its metabolites (M-5, M-6, M-14) and atropine in human, pig...

The time courses of the changes in contractile force and in transmembrane potentials induced by cardiac glycosides in guinea-pig papillary muscle

Lüllmann, H., Ravens, Ursula

1. The effects of ouabain, digoxin, digoxigenin monodigitoxoside, digoxigenin bisdigitoxoside and digitoxigenin bisdigitoxoside on the force of contraction and on the transmembrane action potential...