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https://www.readbyqxmd.com/read/28213506/role-of-apamin-sensitive-calcium-activated-small-conductance-potassium-currents-on-the-mechanisms-of-ventricular-fibrillation-in-pacing-induced-failing-rabbit-hearts
#1
Dechun Yin, Yu-Cheng Hsieh, Wei-Chung Tsai, Adonis Zhi-Yang Wu, Zhaolei Jiang, Yi-Hsin Chan, Dongzhu Xu, Na Yang, Changyu Shen, Zhenhui Chen, Shien-Fong Lin, Peng-Sheng Chen, Thomas H Everett
BACKGROUND: Ventricular fibrillation (VF) during heart failure is characterized by stable reentrant spiral waves (rotors). Apamin-sensitive small-conductance calcium-activated potassium currents (IKAS) are heterogeneously upregulated in failing hearts. We hypothesized that IKAS influences the location and stability of rotors during VF. METHODS AND RESULTS: Optical mapping was performed on 9 rabbit hearts with pacing-induced heart failure. The epicardial right ventricular and left ventricular surfaces were simultaneously mapped in a Langendorff preparation...
February 2017: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/28209766/glycosylated-chromogranin-a-in-heart-failure-implications-for-processing-and-cardiomyocyte-calcium-homeostasis
#2
Anett Hellebø Ottesen, Cathrine R Carlson, William E Louch, Mai Britt Dahl, Ragnhild A Sandbu, Rune Forstrøm Johansen, Hilde Jarstadmarken, Magnar Bjørås, Arne Didrik Høiseth, Jon Brynildsen, Ivar Sjaastad, Mats Stridsberg, Torbjørn Omland, Geir Christensen, Helge Røsjø
BACKGROUND: Chromogranin A (CgA) levels have previously been found to predict mortality in heart failure (HF), but currently no information is available regarding CgA processing in HF and whether the CgA fragment catestatin (CST) may directly influence cardiomyocyte function. METHODS AND RESULTS: CgA processing was characterized in postinfarction HF mice and in patients with acute HF, and the functional role of CST was explored in experimental models. Myocardial biopsies from HF, but not sham-operated mice, demonstrated high molecular weight CgA bands...
February 2017: Circulation. Heart Failure
https://www.readbyqxmd.com/read/28169003/increased-calcium-leak-associated-with-reduced-calsequestrin-expression-in-hyperthyroid-cardiomyocytes
#3
David R de Alba-Aguayo, Natalia Pavón, Martha Mercado-Morales, Miyamin Miranda-Saturnino, Mavil López-Casamichana, Agustin Guerrero-Hernández, Angelica Rueda
INTRODUCTION: Calcium (Ca(2+)) leak during cardiac diastole is chiefly mediated by intracellular Ca(2+) channel/Ryanodine Receptors. Increased diastolic Ca(2+) leak has been proposed as the mechanism underlying the appearance of hereditary arrhythmias. However, little is known about alterations in diastolic Ca(2+) leak and the specific roles played by key intracellular Ca(2+)-handling proteins in hyperthyroidism, a known arrhythmogenic condition. AIM: We sought to determine whether there were modifications in diastolic Ca(2+) leak, based on the recording of Ca(2+) sparks and Ca(2+) waves; we also investigated changes in the expression and activity of key Ca(2+) handling proteins, including ryanodine receptors, Sarco-Endoplasmic Reticulum Ca(2+) ATPase pump and calsequestrin in isolated left-ventricular cardiomyocytes isolated from hyperthyroid rats...
January 23, 2017: Cell Calcium
https://www.readbyqxmd.com/read/28087911/-aortic-stiffness-and-its-influencing-factors-in-patients-with-chronic-kidney-disease
#4
Binxian Ye, Li Zhao, Wei Shen, Yan Ren, Bo Lin, Maosheng Chen, Junda Tang, Xinxin Jiang, Yiwen Li, Qiang He
Objective: To investigate the changes of aortic stiffness and its influencing factors in patients with chronic kidney diseases (CKD). Methods: Eightyfour patients with CKD from Department of Nephrology, Zhejiang Provincial People's Hospital were divided into the dialysis group (CKD stage 5, n=48) and non-dialysis group (CKD stage 3-5, n=36). Clinical data, biochemical parameters and echocardiography findings were collected. SphygmoCor pulse wave analysis system was used to obtain pulse wave analysis (PWA) parameters including central aortic systolic blood pressure (CSP), central pulse pressure (CPP), augmented pressure (AP), augmentation index (AIX), and heart rate 75-adjusted augmentation index (HR75AIX)...
May 25, 2016: Zhejiang da Xue Xue Bao. Yi Xue Ban, Journal of Zhejiang University. Medical Sciences
https://www.readbyqxmd.com/read/27773880/high-calcium-exposure-to-frog-heart-a-simple-model-representing-hypercalcemia-induced-ecg-abnormalities
#5
Itsuro Kazama
By simply adding a high concentration of calcium solution to the surface of the bullfrog heart, we reproduced electrocardiogram (ECG) abnormalities representing those observed in hypercalcemia, such as Osborn waves and shortening of the QT interval. The rise in extracellular calcium concentration may have activated the outward potassium currents during phase 3 of the action potential, and thus decreased its duration. In addition to the known decrease in the duration of phase 2, such changes in phase 3 were also likely to contribute to the shortening of the QT interval...
January 20, 2017: Journal of Veterinary Medical Science
https://www.readbyqxmd.com/read/27694214/dyssynchronous-calcium-removal-in-heart-failure-induced-atrial-remodeling
#6
F Hohendanner, J DeSantiago, F R Heinzel, L A Blatter
We tested the hypothesis that in atrial myocytes from a rabbit left ventricular heart failure (HF) model, spatial inhomogeneity and temporal dyssynchrony of Ca removal during excitation-contraction coupling together with increased Na/Ca exchange (NCX) activity generate a substrate for proarrhythmic Ca release. Ca removal occurs via Ca reuptake into the sarcoplasmic reticulum and extrusion via NCX exclusively in the cell periphery since rabbit atrial myocytes lack transverse tubules. Ca removal kinetics were assessed by the time constant τ of decay of local peripheral subsarcolemmal (SS) and central (CT) action potential (AP)-induced Ca transients (CaTs) recorded in confocal line scan mode (using Fluo-4)...
December 1, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27457951/mechanical-signaling-coordinates-the-embryonic-heartbeat
#7
Kevin K Chiou, Jason W Rocks, Christina Yingxian Chen, Sangkyun Cho, Koen E Merkus, Anjali Rajaratnam, Patrick Robison, Manorama Tewari, Kenneth Vogel, Stephanie F Majkut, Benjamin L Prosser, Dennis E Discher, Andrea J Liu
In the beating heart, cardiac myocytes (CMs) contract in a coordinated fashion, generating contractile wave fronts that propagate through the heart with each beat. Coordinating this wave front requires fast and robust signaling mechanisms between CMs. The primary signaling mechanism has long been identified as electrical: gap junctions conduct ions between CMs, triggering membrane depolarization, intracellular calcium release, and actomyosin contraction. In contrast, we propose here that, in the early embryonic heart tube, the signaling mechanism coordinating beats is mechanical rather than electrical...
August 9, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27372350/effect-of-sphingosine-1-phosphate-on-l-type-calcium-current-and-ca-2-transient-in-rat-ventricular-myocytes
#8
Emmanuel Eroume-A Egom, James S H Bae, Rebecca Capel, Mark Richards, Yunbo Ke, Rebabonye B Pharithi, Vincent Maher, Peter Kruzliak, Ming Lei
Modulation of Ca(2+) homoeostasis in cardiac myocytes plays a major role in beat-to-beat regulation of heart function. Previous studies suggest that sphingosine-1-phosphate (S1P), a biologically active sphingomyelin metabolite, regulates Ca(2+) handling in cardiac myocytes, but the underlying mechanism is unclear. In the present study, we tested the hypothesis that S1P-induced functional alteration of intracellular Ca(2+) handling includes the L-type calcium channel current (ICa,L) via a signalling pathway involving P21-activated kinase 1 (Pak1)...
August 2016: Molecular and Cellular Biochemistry
https://www.readbyqxmd.com/read/27336310/electrophysiology-of-heart-failure-using-a-rabbit-model-from-the-failing-myocyte-to-ventricular-fibrillation
#9
Aditya V S Ponnaluri, Luigi E Perotti, Michael Liu, Zhilin Qu, James N Weiss, Daniel B Ennis, William S Klug, Alan Garfinkel
Heart failure is a leading cause of death, yet its underlying electrophysiological (EP) mechanisms are not well understood. In this study, we use a multiscale approach to analyze a model of heart failure and connect its results to features of the electrocardiogram (ECG). The heart failure model is derived by modifying a previously validated electrophysiology model for a healthy rabbit heart. Specifically, in accordance with the heart failure literature, we modified the cell EP by changing both membrane currents and calcium handling...
June 2016: PLoS Computational Biology
https://www.readbyqxmd.com/read/27222313/inhibition-of-rac1-reduces-store-overload-induced-calcium-release-and-protects-against-ventricular-arrhythmia
#10
Lili Zhang, Xiangru Lu, Le Gui, Yan Wu, Stephen M Sims, Guoping Wang, Qingping Feng
Rac1 is a small GTPase and plays key roles in multiple cellular processes including the production of reactive oxygen species (ROS). However, whether Rac1 activation during myocardial ischaemia and reperfusion (I/R) contributes to arrhythmogenesis is not fully understood. We aimed to study the effects of Rac1 inhibition on store overload-induced Ca(2+) release (SOICR) and ventricular arrhythmia during myocardial I/R. Adult Rac1(f/f) and cardiac-specific Rac1 knockdown (Rac1(ckd) ) mice were subjected to myocardial I/R and their electrocardiograms (ECGs) were monitored for ventricular arrhythmia...
August 2016: Journal of Cellular and Molecular Medicine
https://www.readbyqxmd.com/read/27207297/calcium-wave-propagation-triggered-by-local-mechanical-stimulation-as-a-method-for-studying-gap-junctions-and-hemichannels
#11
Jegan Iyyathurai, Bernard Himpens, Geert Bultynck, Catheleyne D'hondt
Intercellular communication is essential for the coordination and synchronization of cellular processes. Gap junction channels play an important role to communicate between cells and organs, including the brain, lung, liver, lens, retina, and heart. Gap junctions enable a direct route for ions like calcium and potassium, and low molecular weight compounds, such as inositol 1,4,5-trisphosphate, cyclic adenosine monophosphate, and various kinds of metabolites to pass between cells. Intercellular calcium wave propagation evoked by a local mechanical stimulus is one of the gap junction assays to study intercellular communication...
2016: Methods in Molecular Biology
https://www.readbyqxmd.com/read/27073007/a-review-of-the-potential-pathogenicity-and-management-of-frequent-premature-ventricular-contractions
#12
Laurence Laplante, Bruno S Benzaquen
Very frequent premature ventricular complexes (PVCs) may be a reversible cause of dilated cardiomyopathy. Literature on this largely unrecognized entity has increased in the last 15 years. This paper reviews the literature on the consequences of frequent PVCs on myocardial function and management of PVC-associated cardiomyopathy. The authors reviewed articles published in English before June 2015 describing pathophysiology, risk factors, symptoms, time course, treatment, and outcome of cardiomyopathy associated with PVCs...
July 2016: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/27022002/not-your-regular-high-cardiac-dysrhythmias-caused-by-loperamide
#13
Rachel Sarah Wightman, Robert S Hoffman, Mary Ann Howland, Brian Rice, Rana Biary, Daniel Lugassy
OBJECTIVE: Loperamide, a non-prescription anti-diarrheal agent, is a peripheral mu-opioid receptor agonist that is excluded from the blood-brain barrier by p-glycoprotein at therapeutic doses. Overdoses of loperamide penetrate the central nervous system (CNS), leading to abuse. We report cardiac conduction abnormalities and dysrhythmias after ingestion of a recreational supra-therapeutic dose of loperamide confirmed with an elevated blood loperamide concentration. CASE DETAILS: A 48-year-old woman with a history of alcohol and benzodiazepine abuse presented to the emergency department (ED) with somnolence, weakness and slurred speech...
June 2016: Clinical Toxicology
https://www.readbyqxmd.com/read/26972634/vascular-risk-assessment-in-older-adults-without-a-history-of-cardiovascular-disease
#14
REVIEW
P Bambrick, W S Tan, R Mulcahy, G A Pope, J Cooke
Modern cardiovascular risk prediction tools, which have their genesis in the Framingham Heart Study, have allowed more accurate risk stratification and targeting of treatments worldwide over the last seven decades. Better cardiovascular risk factor control during this time has led to a reduction in cardiovascular mortality and, at least in part, to improved life expectancy. As a result, western societies as a whole have seen a steady increase in the proportion of older persons in their populations. Unfortunately, several studies have shown that the same tools which have contributed to this increase cannot be reliably extrapolated for use in older generations...
June 15, 2016: Experimental Gerontology
https://www.readbyqxmd.com/read/26818679/cardiac-expression-of-the-crem-repressor-isoform-crem-ib%C3%AE-c-x-in-mice-leads-to-arrhythmogenic-alterations-in-ventricular-cardiomyocytes
#15
J S Schulte, E Fehrmann, M A Tekook, D Kranick, B Fels, N Li, X H T Wehrens, A Heinick, M D Seidl, W Schmitz, F U Müller
Chronic β-adrenergic stimulation is regarded as a pivotal step in the progression of heart failure which is associated with a high risk for arrhythmia. The cAMP-dependent transcription factors cAMP-responsive element binding protein (CREB) and cAMP-responsive element modulator (CREM) mediate transcriptional regulation in response to β-adrenergic stimulation and CREM repressor isoforms are induced after stimulation of the β-adrenoceptor. Here, we investigate whether CREM repressors contribute to the arrhythmogenic remodeling in the heart by analyzing arrhythmogenic alterations in ventricular cardiomyocytes (VCMs) from mice with transgenic expression of the CREM repressor isoform CREM-IbΔC-X (TG)...
March 2016: Basic Research in Cardiology
https://www.readbyqxmd.com/read/26778902/myocardial-function-in-saudi-adolescents-with-vitamin-d-deficiency-tissue-doppler-imaging-study
#16
Mohamed Matter, Enas El-Sherbiny, Atef Elmougy, Mohamed Abass, Sahar Aldossary, Waleed Abu Ali
Vitamin D deficiency is a common health problem in Saudi Arabia especially in children and adolescents. Many studies have reported the relation between low 25-Hydroxyvitamin D (25(OH)D) levels with cardiovascular diseases risk factors as well as cardiovascular events, including stroke, myocardial infarction, and congestive heart failure. This study was conducted to evaluate the effect of 25(OH)D deficiency on the myocardial function and other echocardiographic variables in adolescent, using tissue Doppler imaging (TDI) and to correlate these parameters with 25(OH)D level...
January 2016: Journal of the Saudi Heart Association
https://www.readbyqxmd.com/read/26764327/garlic-and-heart-disease
#17
REVIEW
Ravi Varshney, Matthew J Budoff
BACKGROUND: Thousands of studies have been published based on animal and human studies evaluating garlic's effects and safety. OBJECTIVE: We reviewed the available literature investigating the effects of garlic supplements on hypertension, hypercholesterolemia, C-reactive protein (CRP), pulse wave velocity (PWV), and coronary artery calcium (CAC), as well as available data on side effects. METHODS: We searched PubMed for all human studies using medical subject heading words through 30 May 2013 and assessed relevant review articles and original studies...
February 2016: Journal of Nutrition
https://www.readbyqxmd.com/read/26687545/mechano-electric-feedback-in-one-dimensional-model-of-myocardium
#18
Nathalie A Vikulova, Leonid B Katsnelson, Alexander G Kursanov, Olga Solovyova, Vladimir S Markhasin
We utilized our earlier developed 1D mathematical model of the heart muscle strand to study contribution of the bilateral interactions between excitation and contraction on the cellular and tissue levels to the local and global myocardium function. Numerical experiments on the model showed that an initially uniform strand, formed on the inherently identical cells, became functionally heterogeneous due to the asynchronous excitation via the electrical wave spread. Mechanical interactions between the cells and the mechano-electric feedback beat-to-beat affect the functional characteristics of coupled cardiomyocytes further, adjusting their electrical and mechanical heterogeneity to the activation timing...
August 2016: Journal of Mathematical Biology
https://www.readbyqxmd.com/read/26676157/an-open-label-parallel-group-study-to-assess-the-effects-of-amlodipine-and-cilnidipine-on-pulse-wave-velocity-and-augmentation-pressures-in-mild-to-moderate-essential-hypertensive-patients
#19
Rama Mohan Pathapati, Sujith Tumkur Rajashekar, Madhavulu Buchineni, Rajesh Kumar Meriga, Chirra Bhakthavasthala Reddy, Kolla Praveen Kumar
INTRODUCTION: Hypertension is a major cardiovascular risk factor, which affects both large and small arteries. Because of the associated morbidity and mortality and the cost to society, it is an important public health challenge. Population based studies have reported that large artery stiffness is an important determinant of cardiovascular events and mortality in general population and in patients with hypertension. This study was designed to compare the effects of 8 weeks blood pressure control using Amlodepine and cilnidipine on haemodynamic parameters and vascular indices in mild to moderate hypertensive patients...
November 2015: Journal of Clinical and Diagnostic Research: JCDR
https://www.readbyqxmd.com/read/26660552/mouse-ecg-findings-in-aging-with-conduction-system-affecting-drugs-and-in-cardiac-pathologies-development-and-validation-of-ecg-analysis-algorithm-in-mice
#20
Mari Merentie, Jukka A Lipponen, Marja Hedman, Antti Hedman, Juha Hartikainen, Jenni Huusko, Line Lottonen-Raikaslehto, Viktor Parviainen, Svetlana Laidinen, Pasi A Karjalainen, Seppo Ylä-Herttuala
Mouse models are extremely important in studying cardiac pathologies and related electrophysiology, but very few mouse ECG analysis programs are readily available. Therefore, a mouse ECG analysis algorithm was developed and validated. Surface ECG (lead II) was acquired during transthoracic echocardiography from C57Bl/6J mice under isoflurane anesthesia. The effect of aging was studied in young (2-3 months), middle-aged (14 months) and old (20-24 months) mice. The ECG changes associated with pharmacological interventions and common cardiac pathologies, that is, acute myocardial infarction (AMI) and progressive left ventricular hypertrophy (LVH), were studied...
December 2015: Physiological Reports
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