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adenosine vs verapamil

K-L Habicht, N S Singh, M A Khadeer, R Shimmo, I W Wainer, R Moaddel
Glioblastoma multiforme is an aggressive form of human astrocytoma, with poor prognosis due to multi-drug resistance to a number of anticancer drugs. The observed multi-drug resistance is primarily due to the efflux activity of ATP-Binding Cassette (ABC) efflux transporters such as Pgp, MRP1 and BCRP. The expression of these transporters has been demonstrated in nuclear and cellular membranes of the LN-229 human glioblastoma cell line. Nuclear membrane and cellular membrane fragments from LN-229 cells were immobilized on the IAM stationary phase to create nuclear and cellular membrane affinity chromatography columns, (NMAC(LN-229)) and (CMAC(LN-229)), respectively...
April 25, 2014: Journal of Chromatography. A
Cengizhan Türkoğlu, Muzaffer Oztürk, Farid Aliyev, Inci Firatli, Nilgün Incesoy
BACKGROUND: In this study we evaluate wide QRS complexes observed during pharmacologic termination of supraventricular tachycardias. METHODS: Patients with supraventricular tachycardia, undergoing electrophysiologic study were enrolled. 12 mg of adenosine or 10 mg of verapamil were administered during tachycardia, under continuous monitoring of intaracardiac and surface electrocardiograms. Electrocardiographic features of ventricular ectopy were noted. RESULTS: Seventy-four patients were enrolled...
October 2009: Annals of Noninvasive Electrocardiology
Chinasa Anugwom, Sheryl Sulangi, Robert Dachs
No abstract text is available yet for this article.
June 1, 2007: American Family Physician
Akihiro Takano, Hiroyuki Kusuhara, Tetsuya Suhara, Ichiro Ieiri, Takuya Morimoto, Young-Joo Lee, Jun Maeda, Yoko Ikoma, Hiroshi Ito, Kazutoshi Suzuki, Yuichi Sugiyama
UNLABELLED: P-glycoprotein (P-gp) is a membrane protein that functions as an adenosine triphosphate-dependent efflux pump for xenobiotics at the blood-brain barrier (BBB). Polymorphisms of MDR1 gene have been reported to be associated with the expression level of P-gp. (11)C-Verapamil is considered to be one of the suitable radioligands for evaluating P-gp functions. However, the metabolites of verapamil might complicate the quantitative analysis because of their possible brain penetration...
September 2006: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
Amanda J Zatta, G Paul Matherne, John P Headrick
This study evaluated the ability of A1 and A3 adenosine receptor (AR) agonism, and A1, A2A, A2B and A3AR antagonism (revealing "intrinsic" responses), to modify post-ischemic coronary dysfunction in mouse heart. Vascular function was assessed before and after 20 min global ischemia and 30-45 min reperfusion in Langendorff perfused C57/Bl6 mouse hearts. Ischemic insult impaired coronary sensitivity to the endothelial-dependent dilators ADP (pEC50=6.8+/-0.1 vs. 7.6+/-0.1, non-ischemic) and acetylcholine (pEC50=6...
April 18, 2006: Life Sciences
Chi Hang Lee, Hwee Bee Wong, Huay Cheem Tan, Jun Jie Zhang, Swee Guan Teo, Hean Yee Ong, Adrian Low, Antono Sutandar, Yean Teng Lim
BACKGROUND: Occurrence of no reflow phenomenon during percutaneous coronary intervention (PCI) is associated with increased mortality. Although intracoronary medications can improve coronary flow, the effect on mortality is not known. METHODS: Patients who had PCI for myocardial infarction (MI) at the Singapore National University Hospital from January 2000 to March 2004 were studied. Our analysis stratified patients into three groups according to the occurrence and persistence of no reflow during PCI...
August 2005: Journal of Interventional Cardiology
Kuo-Hung Lin, Chi-Tai Kuo, Nazar Luqman, Kuang-Hung Hsu, Chiun-Li Wang, Tsu-Shiu Hsu, Ying-Shiung Lee
Electrophysiological characteristics of an accessory pathway (AP) with a long ventriculoatrial (VA) interval (arbitrarily defined as > or = 50 ms and absence of continuous electrical activity) and no retrograde decremental property are described in this study. Fifteen patients (group 1) were compared with 171 patients with normal VA conduction (group 2). Mean VA conduction time was 77 +/- 24 versus 34 +/- 12 ms in group 1 versus group 2, respectively. Group 1 patients were older (55 +/- 14 vs 40 +/- 14 years), the male to female ratio was higher (2...
September 2004: Pacing and Clinical Electrophysiology: PACE
Piercarlo Ballo, Daniele Bernabò, Sergio Antonio Faraguti
AIMS: To analyse whether heart rate may affect the efficacy of adenosine, verapamil and carotid sinus massage in terminating symptomatic episodes of paroxysmal supraventricular tachycardia (PSVT) in adults. METHODS AND RESULTS: The study population was selected among 175 adult patients, affected by symptomatic PSVT. One hundred and six of them were considered eligible for the study. Each subject received one of the following treatments: verapamil, 5 mg intravenously (IV) in 5-10 min, followed by 1-5 microg/kg/min; adenosine, 6 mg IV, followed by 12 mg IV after 2-3 min; carotid sinus massage...
August 2004: European Heart Journal
K Jamroziak, P Smolewski, B Cebula, A Szmigielska-Kaplon, Z Darzynkiewicz, T Robak
Prolonged lifespan of monoclonal lymphocytes in B-cell lymphocytic leukemia (B-CLL) arises from their resistance to programmed cell death. In contrast, when cultured in vitro, B-CLL tumour cells rapidly undergo apoptosis. There is mounting evidence that P-glycoprotein (P-gp), an adenosine triphosphate-binding cassette (ABC) family transporter, plays a significant role in the regulation of apoptosis induced by various stimuli. Since P-gp is commonly expressed in B-CLL cells, we aimed to establish whether its expression level influences resistance to spontaneous apoptosis in B-CLL...
2004: Neoplasma
Kang-an Cheng
OBJECTIVE: To compare the safety and efficacy of intravenous adenosine with verapamil in terminating acute episodes of paroxysmal supraventricular tachycardia. METHODS: A randomized, multicenter trial to evaluate dose response in patients receiving adenosine and to compare the effects of adenosine with those of verapamil. A total of 122 patients with a tachycardia electrocardiographically consistent with paroxysmal supraventricular tachycardia were entered into the protocol...
November 2003: Zhonghua Nei Ke za Zhi [Chinese Journal of Internal Medicine]
R D Jones, L N Ruban, I E Morton, S A Roberts, K M English, K S Channer, T H Jones
Testosterone-induced vasodilatation is proposed to contribute to the beneficial effects associated with testosterone replacement therapy in men with cardiovascular disease, and is postulated to occur via either direct calcium channel blockade, or through potassium channel activation via increased production of cyclic nucleotides. We utilised flow cytometry to investigate whether testosterone inhibits the increase in cellular fluorescence induced by prostaglandin F(2alpha) in A7r5 smooth muscle cells loaded with the calcium fluorescent probe indo-1-AM, and to study the cellular mechanisms involved...
September 2003: Journal of Endocrinology
Laurent M Riou, Catherine Ghezzi, Gérald Vanzetto, Alexis Broisat, Jean-Paul Mathieu, René Bontron, Roberto Pasqualini, Daniel Fagret
UNLABELLED: Bis(N-ethoxy,N-ethyldithiocarbamato)nitrido technetium (V) ((99m)Tc) ((99m)TcN-NOET) is a new myocardial perfusion imaging agent currently undergoing phase III clinical trials in the United States and in Europe. (99m)TcN-NOET cellular uptake has been shown to be inhibited by the calcium channel inhibitor verapamil in cultured newborn rat cardiomyocytes. However, the effect of verapamil on in situ (99m)TcN-NOET myocardial uptake remains unknown. Therefore, the aim of this study was to evaluate whether the inhibitory effect of verapamil on the cellular uptake of (99m)TcN-NOET shown in vitro could be reproduced in situ in a canine model of normal and ischemic myocardium...
June 2003: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
Laurent M Riou, Mirta Ruiz, Jayson M Rieger, Timothy L Macdonald, Denny D Watson, Joel Linden, George A Beller, David K Glover
OBJECTIVES: The study was done to determine the effects of propranolol, enalaprilat, verapamil, and caffeine on the vasodilatory properties of the adenosine A(2A)-receptor agonist ATL-146e (ATL). BACKGROUND: ATL is a new adenosine A(2A)-receptor agonist proposed as a vasodilator for myocardial stress perfusion imaging. Beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, and calcium blockers are commonly used for the treatment of coronary artery disease (CAD), and their effect on ATL-mediated vasodilation is unknown...
November 6, 2002: Journal of the American College of Cardiology
Ewa Landwojtowicz, Pierluigi Nervi, Anna Seelig
Extracellular acidification rates (ECARs) in response to eight different drugs activating or inhibiting the ATPase of P-glycoprotein (Pgp) were measured in real time by means of a Cytosensor microphysiometer in MDR1-transfected and corresponding wild-type cell lines, i.e., pig kidney cells (LLC-MDR1 and LLC-PK1) and mouse embryo fibroblasts (NIH-MDR-G185 and NIH3T3). The ECARs showed a bell-shaped dependence on drug concentration (log scale) in transfected cells but were negligibly small in wild-type cells...
June 25, 2002: Biochemistry
Frederic Winnock, Zhidong Ling, Rene De Proft, Sandra Dejonghe, Frans Schuit, Frans Gorus, Daniel Pipeleers
Pancreatic beta-cells express glutamate decarboxylase (GAD), which is responsible for the production and release of gamma-aminobutyric acid (GABA). Over a 24-h culture period, total GABA release by purified rat beta-cells is eightfold higher than the cellular GABA content and can thus be used as an index of cellular GAD activity. GABA release is 40% reduced by glucose (58 pmol/10(3) cells at 10 mM glucose vs. 94 pmol at 3 mM glucose, P < 0.05). This suppressive effect of glucose was not observed when glucose metabolism was blocked by mannoheptulose or 2,4-dinitrophenol; it was amplified when ATP-dependent beta-cell activities were inhibited by addition of diazoxide, verapamil, or cycloheximide or by reduction of extracellular calcium levels; it was counteracted when beta-cell functions were activated by nonmetabolized agents, such as glibenclamide, IBMX, glucagon, or glucacon-like peptide-1 (GLP-1), which are known to stimulate calcium-dependent activities, such as hormone release and calcium-dependent ATPases...
April 2002: American Journal of Physiology. Endocrinology and Metabolism
T C Bania, B Blaufeux, S Hughes, G L Almond, P Homel
UNLABELLED: Calcium chloride (CaCl(2)) is ineffective in severe calcium channel antagonist overdoses. Digoxin increases intracellular calcium by inhibiting the sodium-potassium adenosine triphosphatase enzymes. OBJECTIVE: To examine the effect of calcium and digoxin on the treatment of verapamil toxicity. METHODS: Sixteen dogs were instrumented to monitor hemodynamics. Verapamil toxicity (50% decrease in mean arterial pressure) was induced with verapamil (VER) at 6 mg/kg/hr and maintained for 30 minutes by titrating the VER rate...
October 2000: Academic Emergency Medicine: Official Journal of the Society for Academic Emergency Medicine
H Farghali, E Kmonícková, H Lotková, J Martínek
The aim of this study was to investigate the effects of calcium channel blockers on tertbutyl hydroperoxide (TBH) induced liver injury using isolated perfused rat hepatocytes. Rat hepatocytes were immobilized in agarose threads and perfused with Williams E medium. Hepatocyte injury was induced by the addition of tertbutyl hydroperoxide (1 mM) to the perfusion medium 30 min after the addition of either verapamil or diltiazim. Hepatocyte injury was observed by monitoring the functional and metabolic competence of hepatocytes or by ultrastructural morphological examination of hepatocytes...
2000: Physiological Research
N Shibata, J Morimoto, N Hoshino, T Minouchi, A Yamaji
Factors that affect the absorption of cyclosporin A (CsA) were examined in gentamicin-induced acute renal failure (ARF) rats. In ARF rats, the area under the blood CsA concentration-time curve after oral administration was significantly decreased in comparison with that of control rats; 5.81 +/- 0.55 vs 11.30 +/- 1.59 mg h mL(-1)(mean+/-s.e.m.), respectively, and the relative bioavailabilities in ARF and control rats after oral administration were 15.2% and 43.4%, respectively. The flow rate of bile and the amount of bile acids in ARF rats were markedly decreased to about 61% of control, and 41% of control, respectively...
March 2000: Renal Failure
J P Headrick, J C McKirdy, R J Willis
Metabolic and functional responses to extracellular Mg2+ concentration ([Mg2+]o) were studied in perfused rat heart. Elevations of [Mg2+]o from 1.2 to 2.4, 5.0, and 8.0 mM dose dependently reduced contractile function and myocardial oxygen consumption (MVO2) up to 80%. Intracellular Mg2+ concentration ([Mg2+]i) remained stable (0.45-0.50 mM) during perfusion with 1.2-5. 0 mM [Mg2+]o but increased to 0.81 +/- 0.14 mM with 8.0 mM [Mg2+]o. Myocardial ATP was unaffected by [Mg2+]o, phosphocreatine (PCr) increased up to 25%, and Pi declined by up to 50%...
September 1998: American Journal of Physiology
R K Shepard, A Natale, B S Stambler, M A Wood, D M Gilligan, K A Ellenbogen
The physiology of the escape rhythm (ER) and its response to pharmacological modulation under varying autonomic conditions were studied 48 patients undergoing radiofrequency ablation of the atrioventricular junction (AVJ) for refractory atrial fibrillation. The QRS morphology and cycle length (CL) of the baseline ER were measured 15 minutes postablation. The CL of the ER was measured in response to doses of isoproterenol, atropine, adenosine, lidocaine, and verapamil. The ER QRS was narrow (QRS < 120 ms) in 20 patients and wide (QRS > 120 ms) in 28 patients...
May 1998: Pacing and Clinical Electrophysiology: PACE
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