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https://www.readbyqxmd.com/read/28437860/chronic-inhibition-of-fatty-acid-amide-hydrolase-by-urb597-produces-differential-effects-on-cardiac-performance-in-normotensive-and-hypertensive-rats
#1
Anna Pedzinska-Betiuk, Jolanta Weresa, Marek Toczek, Marta Baranowska-Kuczko, Irena Kasacka, Ewa Harasim-Symbor, Barbara Malinowska
BACKGROUND AND PURPOSE: Fatty acid amide hydrolase (FAAH) inhibitors are postulated to possess anti-hypertensive potential, because their acute injection decreases blood pressure (BP) in spontaneously hypertensive rats (SHR) partially through normalization of cardiac contractile function. Here, we examined whether the potential hypotensive effect of chronic FAAH inhibition by URB597 in hypertensive rats correlates with changes in cardiac performance. EXPERIMENTAL APPROACH: Experiments were performed using perfused hearts and left atria isolated from 8-10 week old SHR, age-matched deoxycorticosterone acetate (DOCA-salt) rats and normotensive controls chronically treated with URB597 (1 mg kg(-1) ) or vehicle...
April 24, 2017: British Journal of Pharmacology
https://www.readbyqxmd.com/read/28410965/permissive-role-of-reduced-inwardly-rectifying-potassium-current-density-in-the-automaticity-of-the-guinea-pig-pulmonary-vein-myocardium
#2
Yayoi Tsuneoka, Masahiko Irie, Yusuke Tanaka, Takahiko Sugimoto, Yuka Kobayashi, Taichi Kusakabe, Keisuke Kato, Shogo Hamaguchi, Iyuki Namekata, Hikaru Tanaka
The electrophysiological properties underlying the automaticity of the guinea pig pulmonary vein myocardium were studied. About 30% of the isolated pulmonary vein tissue preparations showed spontaneous electrical activity, as shown by glass microelectrode recordings from their myocardial layer. The remaining quiescent preparations had a resting membrane potential less negative than that in the left atria. Blockade of the acetylcholine activated potassium current (IK-ACh) by tertiapin induced a depolarizing shift of the resting membrane potential and automatic electrical activity in the pulmonary vein, but not in the atria...
March 28, 2017: Journal of Pharmacological Sciences
https://www.readbyqxmd.com/read/28386845/sub-physiological-oxygen-levels-optimal-for-growth-and-survival-of-human-atrial-cardiac-stem-cells
#3
Deepthi Sreerengam RajendranNair, Jayakumar Karunakaran, Renuka R Nair
Cardiac stem cells reside in niches where the oxygen levels are close to 3%. For cytotherapy, cells are conventionally expanded in ambient oxygen (21% O2) which represents hyperoxia compared to the oxygen tension of niches. Cardiosphere-derived cells (CDCs) are then transplanted to host tissue with lower-O2 levels. The high-O2 gradient can reduce the efficacy of cultured cells. Based on the assumption that minimizing injury due to O2 gradients will enhance the yield of functionally efficient cells, CDCs were cultured in 3% O2 and compared with cells maintained in ambient O2...
April 6, 2017: Molecular and Cellular Biochemistry
https://www.readbyqxmd.com/read/28382232/resveratrol-enhances-the-inotropic-effect-but-inhibits-the-proarrhythmic-effect-of-sympathomimetic-agents-in-rat-myocardium
#4
Jesús Hernandez-Cascales
BACKGROUND: Resveratrol is a cardioprotective agent with known antiarrhythmic effects that has recently been shown to inhibit phosphodiesterase (PDE) enzyme activity. Thus, it is possible that resveratrol increases the inotropic effect of sympathomimetic agents, as PDE inhibitors do but, unlike other PDE inhibitors, its effect may not be accompanied by proarrhythmia due to its antiarrhythmic action. This work is aimed to test this hypothesis. METHODS: This is an "in vitro" concentration-response relationship study...
2017: PeerJ
https://www.readbyqxmd.com/read/28343787/relationship-between-rotors-and-complex-fractionated-electrograms-in-atrial-fibrillation-using-a-novel-computational-analysis
#5
Pedro Adragão, Pedro Carmo, Diogo Cavaco, João Carmo, António Ferreira, Francisco Moscoso Costa, Maria Salomé Carvalho, João Mesquita, Rita Quaresma, Francisco Belo Morgado, Miguel Mendes
INTRODUCTION: Rotors and complex fractionated atrial electrograms (CFAEs) have been suggested as possible therapeutic targets in ablation of atrial fibrillation (AF). The aim of this study was to assess the relationship between rotors and CFAEs in patients with AF. METHODS: We studied 18 patients with AF (mean age 69±8 years, 33% female) who underwent rotor ablation and pulmonary vein isolation. Endocardial mapping was performed with a basket catheter to identify the presence, number and location of rotors and CFAEs...
April 2017: Portuguese Journal of Cardiology: An Official Journal of the Portuguese Society of Cardiology
https://www.readbyqxmd.com/read/28328743/acetylcholine-atropine-interactions-paradoxical-effects-on-atrial-fibrillation-inducibility
#6
Yu Liu, Benjamin J Scherlag, Youqi Fan, Wenfang Xia, He Huang, Sunny S Po
Atropine (ATr) is well known as a cholinergic antagonist, however, at low concentrations ATr could paradoxically accentuate the parasympathetic actions of acetylcholine (ACh). In 22 pentobarbital anesthetized dogs, via a left and right thoracotomy, a leak proof barrier was attached to isolate the atrial appendages (AAs) from the rest of the atria. In Group 1(Ach+ATr+Ach), ACh, 100 mM, was placed on the AA followed by the application of ATr, 2mg/cc. The average AFdur was 17±7 minutes. After ATr was applied to the AA and ACh again tested, the AFdur was markedly attenuated (2±2 minutes, p<0...
March 21, 2017: Journal of Cardiovascular Pharmacology
https://www.readbyqxmd.com/read/28255079/frequency-gradient-within-coronary-sinus-predicts-the-long-term-outcome-of-persistent-atrial-fibrillation-catheter-ablation
#7
Xiaomeng Yin, Ziming Zhao, Lianjun Gao, Dong Chang, Xianjie Xiao, Rongfeng Zhang, Qi Chen, Jie Cheng, Yanzong Yang, Yutao Xi, Yunlong Xia
BACKGROUND: The coronary sinus (CS), as a junction of the atria, contributes to atrial fibrillation (AF) by developing unstable reentry, and isolating the atria by ablation at the CS could terminate AF. The present study evaluated whether AF activities at the CS in a subset of patients contributed to AF maintenance and predicted clinical outcome of ablation. METHODS AND RESULTS: We studied 122 consecutive patients who had a first-time radiofrequency ablation for persistent AF...
March 2, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/28243733/biophysical-and-molecular-comparison-of-sodium-current-in-cells-isolated-from-canine-atria-and-pulmonary-vein
#8
Hector Barajas-Martinez, Robert J Goodrow, Dan Hu, Payal Patel, Mayurika Desai, Brian K Panama, Jacqueline A Treat, Gary L Aistrup, Jonathan M Cordeiro
The collar of the pulmonary vein (PV) is the focal point for the initiation of atrial arrhythmias, but the mechanisms underlying how PV cells differ from neighboring left atrial tissue are unclear. We examined the biophysical and molecular properties of INa in cells isolated from the canine pulmonary sleeve and compared the properties to left atrial tissue. PV and left atrial myocytes were isolated and patch clamp techniques were used to record INa. Action potential recordings from either tissue type were made using high-resistance electrodes...
February 27, 2017: Pflügers Archiv: European Journal of Physiology
https://www.readbyqxmd.com/read/28229413/cardiac-progenitor-cell-extraction-from-human-auricles
#9
Paolo Di Nardo, Francesca Pagliari
For many years, myocardial tissue has been considered terminally differentiated and, thus, incapable of regenerating. Recent studies have shown, instead, that cardiomyocytes, at least in part, are slowly substituted by new cells originating by precursor cells mostly embedded into the heart apex and in the atria. We have shown that an elective region of progenitor cell embedding is represented by the auricles, non-contractile atria appendages that can be easily sampled without harming the patient. The protocol here reported describes how from auricles a population of multipotent, cardiogenic cells can be isolated, cultured, and differentiated...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28223472/overexpression-of-sarcoendoplasmic-reticulum-calcium-atpase-2a-promotes-cardiac-sympathetic-neurotransmission-via-abnormal-endoplasmic-reticulum-and-mitochondria-ca-2-regulation
#10
Julia Shanks, Neil Herring, Errin Johnson, Kun Liu, Dan Li, David J Paterson
Reduced cardiomyocyte excitation-contraction coupling and downregulation of the SERCA2a (sarcoendoplasmic reticulum calcium ATPase 2a) is associated with heart failure. This has led to viral transgene upregulation of SERCA2a in cardiomyocytes as a treatment. We hypothesized that SERCA2a gene therapy expressed under a similar promiscuous cytomegalovirus promoter could also affect the cardiac sympathetic neural axis and promote sympathoexcitation. Stellate neurons were isolated from 90 to 120 g male, Sprague-Dawley, Wistar Kyoto, and spontaneously hypertensive rats...
April 2017: Hypertension
https://www.readbyqxmd.com/read/28219708/novel-technique-to-determine-the-pka-of-clonidine-at-prejunctional-%C3%AE-2-adrenoceptors-in-cardiac-and-vascular-sympathetic-transmission
#11
James A Angus, Pravin Rajasekaran, Christine E Wright
Analytical pharmacology draws heavily on the concept of equilibrium of agonist and silent antagonist concentrations competing at a specific receptor site. This condition breaks down in nerve transmission when transmitter release is inhibited by prejunctional α2-adrenoceptors activated by an agonist such as clonidine. We have developed a method that allows the agonist dissociation constant KA of clonidine to be determined in a robust isolated right atrial assay of mouse, rat and guinea pig. By applying low numbers of field pulses 1-4 to prevent autoinhibitory feedback, clonidine shifted the nerve pulse stimulation-tachycardia curves to the right...
April 5, 2017: European Journal of Pharmacology
https://www.readbyqxmd.com/read/28217229/evaluation-of-the-characteristics-of-rotational-activation-at-high-dominant-frequency-and-complex-fractionated-atrial-electrogram-sites-during-atrial-fibrillation
#12
Koji Kumagai, Kentaro Minami, Daisuke Kutsuzawa, Shigeru Oshima
BACKGROUND: High-dominant frequency (DF) and continuous complex fractionated atrial electrogram (CFAE) sites as surrogates for localized sources maintaining atrial fibrillation (AF) are potential AF ablation targets. This study aimed to evaluate the characteristics of a rotational activation at high-DF and continuous CFAE sites in AF patients. METHODS: Thirty-two consecutive AF patients (5 paroxysmal and 27 non-paroxysmal) underwent ablation using the NavX system...
February 2017: Journal of Arrhythmia
https://www.readbyqxmd.com/read/28155995/sinus-node-dysfunction-and-atrial-fibrillation-a-reversible-phenomenon
#13
REVIEW
Larry R Jackson, Bharath Rathakrishnan, Kristen Campbell, Kevin L Thomas, Jonathan P Piccini, Tristram Bahnson, Jonathan A Stiber, James P Daubert
BACKGROUND: Symptomatic sinus node dysfunction (SND) consists of a variety of manifestations, including tachycardia-bradycardia syndrome. Atrial fibrillation (AF) is commonly associated with SND, which complicates the management of both conditions. This paper reviews the epidemiology, pathophysiology, and clinical trial data investigating therapeutic approaches for treatment of patients with both SND and AF. METHODS: The authors reviewed articles published in English describing the epidemiology, pathophysiology, and therapeutic approaches for patients with SND and AF...
February 3, 2017: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/28133984/new-arylsparteine-derivatives-as-positive-inotropic-drugs
#14
Vito Boido, Marcella Ercoli, Michele Tonelli, Federica Novelli, Bruno Tasso, Fabio Sparatore, Elena Cichero, Paola Fossa, Paola Dorigo, Guglielmina Froldi
Positive inotropic agents are fundamental in the treatment of heart failure; however, their arrhythmogenic liability and the increased myocardial oxygen demand strongly limit their therapeutic utility. Pursuing our study on cardiovascular activities of lupin alkaloid derivatives, several 2-(4-substituted-phenyl)-2-dehydrosparteines and 2-(4-substituted-phenyl)sparteines were prepared and tested for inotropic and chronotropic activities on isolated guinea pig atria. Four compounds (6b, 6e, 7b, and 7f) exhibited significant inotropism that, at the higher concentrations, was followed by negative inotropism or toxicity...
December 2017: Journal of Enzyme Inhibition and Medicinal Chemistry
https://www.readbyqxmd.com/read/28123766/low-incidence-of-left-atrial-delayed-enhancement-with-mri-in-patients-with-af-a-single-centre-experience
#15
John P Bois, James Glockner, Phillip M Young, Thomas A Foley, Seth Sheldon, Darrell B Newman, Grace Lin, Douglas L Packer, Peter A Brady
BACKGROUND: Atrial fibrillation (AF) is the most common sustained atrial arrhythmia. One potential target for ablation is left atrial (LA) scar (LAS) regions that may be the substrate for re-entry within the atria, thereby sustaining AF. Identification of LAS through LA delayed gadolinium enhancement (LADE) with MRI has been proposed. OBJECTIVES: We sought to evaluate LADE in patients referred for catheter ablation of AF. METHODS: Prospective analysis was conducted of consecutive patients who underwent pulmonary vein antrum isolation (PVAI) ablation for AF at a single institution...
2017: Open Heart
https://www.readbyqxmd.com/read/28104073/af-ablation-guided-by-spatiotemporal-electrogram-dispersion%C3%A2-without-pulmonary-vein-isolation-a-wholly-patient-tailored-approach
#16
Julien Seitz, Clément Bars, Guillaume Théodore, Sylvain Beurtheret, Nicolas Lellouche, Michel Bremondy, Ange Ferracci, Jacques Faure, Guillaume Penaranda, Masatoshi Yamazaki, Uma Mahesh R Avula, Laurence Curel, Sabrina Siame, Omer Berenfeld, André Pisapia, Jérôme Kalifa
BACKGROUND: The use of intracardiac electrograms to guide atrial fibrillation (AF) ablation has yielded conflicting results. OBJECTIVES: The authors evaluated the usefulness of spatiotemporal dispersion, a visually recognizable electric footprint of AF drivers, for the ablation of all forms of AF. METHODS: The authors prospectively enrolled 105 patients admitted for AF ablation. AF was sequentially mapped in both atria with a 20-pole PentaRay catheter...
January 24, 2017: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/28100216/antispasmodic-bronchodilator-vasorelaxant-and-cardiosuppressant-effects-of-buxus-papillosa
#17
Arif-Ullah Khan, Shamsher Ali, Anwarul-Hassan Gilani, Manzoor Ahmed, Muhammad Iqbal Choudhary
BACKGROUND: The present research was carried out to investigate pharmacological properties of Buxus papillosa C.K. Schneid. (Buxaceae). METHODS: Buxus papillosa extracts of leaves (BpL), stem (BpS), roots (BpR) and BpL fractions: hexane (BpL-H), aqueous (BpL-A) also plant constituent, cyclomicrobuxine effect were studied in jejunum, atria, aorta and tracheal preparations from rabbit and guine-peg. RESULTS: Ca(++) antagonistic effect of BpS, BpR, BpL-H, BpL-A and cyclomicrobuxine were conclusively suggested, when spontaneous contractions of rabbit jejunal preparation was relaxed along with subsequent relaxation of potassium chloride (80 mM) induced contractions...
January 18, 2017: BMC Complementary and Alternative Medicine
https://www.readbyqxmd.com/read/28091410/molecular-mechanisms-of-increased-heart-rate-in-shenxianshengmai-treated-bradycardia-rabbits
#18
Zhou-Ying Liu, Jian Huang, Na-Na Liu, Min Zheng, Tao Zhao, Bu-Chang Zhao, Yi-Min Wang, Jie-Lin Pu
BACKGROUND: The molecular mechanisms of Shenxianshengmai (SXSM), a traditional Chinese medicine, on bradycardia have been incompletely understood. The study tried to investigate the gene expression profile and proteomics of bradycardia rabbits' hearts after SXSM treatment. METHODS: Twenty-four adult rabbits were randomly assigned in four groups: sham, model, model plus SXSM treatment, and sham plus SXSM treatment groups. Heart rate was recorded in all rabbits. Then, total RNA of atria and proteins of ventricle were isolated and quantified, respectively...
January 20, 2017: Chinese Medical Journal
https://www.readbyqxmd.com/read/28059795/evidence-of-a-cardiovascular-function-for-microtubule-associated-protein-tau
#19
Ashenafi H Betrie, Scott Ayton, Ashley I Bush, James A Angus, Peng Lei, Christine E Wright
Aggregation of tau protein into intracellular deposits is a pathognomonic feature of tauopathies such as Alzheimer's disease (AD) and lowering tau is a prominent therapeutic strategy under development. However, the physiological function of tau protein is not well known, particularly in the periphery. Lowering tau protein risks disrupting its physiological role leading to unwanted effects. In this study, the presence of tau protein in cardiac tissue is confirmed and the functional role in the cardiovascular system and the consequences of its loss were explored...
December 3, 2017: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/28011828/changes-in-p-wave-morphology-after-pulmonary-vein-isolation-insights-from-computer-simulations
#20
Mirabeau Saha, Giulio Conte, Maria Luce Caputo, François Regoli, Rolf Krause, Angelo Auricchio, Vincent Jacquemet
AIMS: Apparently conflicting clinical measurements of P-wave duration (PWD) pre- vs. post-ablation have been reported. To assist the interpretation of these clinical data, we used a computer model of the atria and torso to simulate P waves before and after pulmonary vein (PV) isolation. METHODS AND RESULTS: Twenty ablation patterns were designed (segmental or ipsilateral ablation; five distances to PV sleeves; addition of a roof line or not). Possible PV reconnections were introduced as gaps in the ablation lines...
December 2016: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
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