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https://www.readbyqxmd.com/read/28821956/effects-of-ageing-on-pro-arrhythmic-ventricular-phenotypes-in-incrementally-paced-murine-pgc-1%C3%AE-hearts
#1
Shiraz Ahmad, Haseeb Valli, Charlotte E Edling, Andrew A Grace, Kamalan Jeevaratnam, Christopher L-H Huang
A range of chronic clinical conditions accompany cardiomyocyte energetic dysfunction and constitute independent risk factors for cardiac arrhythmia. We investigated pro-arrhythmic and arrhythmic phenotypes in energetically deficient C57BL mice with genetic ablation of the mitochondrial promoter peroxisome proliferator-activated receptor-γ coactivator-1β (Pgc-1β), a known model of ventricular arrhythmia. Pro-arrhythmic and cellular action potential (AP) characteristics were compared in intact Langendorff-perfused hearts from young (12-16 week) and aged (> 52 week), wild-type (WT) and Pgc-1β (-/-) mice...
August 18, 2017: Pflügers Archiv: European Journal of Physiology
https://www.readbyqxmd.com/read/28817623/metformin-attenuates-myocardial-ischemia-reperfusion-injury-via-up-regulation-of-antioxidant-enzymes
#2
Xiaoling Wang, Lei Yang, Licheng Kang, Jing Li, Liang Yang, Jincai Zhang, Jie Liu, Mengmeng Zhu, Qiong Zhang, Yanna Shen, Zhi Qi
The objective was to examine the protective effect of metformin (Met) on myocardial ischemia-reperfusion (IR) injury and whether the mechanism was related to the AMPK/ antioxidant enzymes signaling pathway. Rat Langendorff test and H2O2-treated rat cardiomyocytes (H9c2) were used in this study. Met treatment significantly improved left ventricular (LV) function, reduced infarct size and CK-MB release in comparison with IR group. Decreased TUNEL staining positive cells were also observed in IR+Met group ex vivo...
2017: PloS One
https://www.readbyqxmd.com/read/28811127/attenuation-of-sunitinib-induced-cardiotoxicity-through-the-a3-adenosine-receptor-activation
#3
Hardip Sandhu, Samantha Cooper, Afthab Hussain, Christopher Mee, Helen Maddock
Sunitinib is an anti-cancer tyrosine kinase inhibitor associated with severe cardiotoxic adverse effects. Using rat Langendorff heart model and human acute myeloid leukaemia 60 (HL60) cell line we detected the involvement of protein kinase C (PKC) α during Sunitinib-induced cardiotoxicity and the effect of Sunitinib on cancer progression. The cardioprotective and anti-cancer properties of the A3 adenosine receptor agonist 2-chloro-N6-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (IB-MECA) were investigated...
August 12, 2017: European Journal of Pharmacology
https://www.readbyqxmd.com/read/28804678/capacitively-coupled-arrays-of-multiplexed-flexible-silicon-transistors-for-long-term-cardiac-electrophysiology
#4
Hui Fang, Ki Jun Yu, Christopher Gloschat, Zijian Yang, Chia-Han Chiang, Jianing Zhao, Sang Min Won, Siyi Xu, Michael Trumpis, Yiding Zhong, Enming Song, Seung Won Han, Yeguang Xue, Dong Xu, Gert Cauwenberghs, Matthew Kay, Yonggang Huang, Jonathan Viventi, Igor R Efimov, John A Rogers
Advanced capabilities in electrical recording are essential for the treatment of heart-rhythm diseases. The most advanced technologies use flexible integrated electronics; however, the penetration of biological fluids into the underlying electronics and any ensuing electrochemical reactions pose significant safety risks. Here, we show that an ultrathin, leakage-free, biocompatible dielectric layer can completely seal an underlying layer of flexible electronics while allowing for electrophysiological measurements through capacitive coupling between tissue and the electronics, and thus without the need for direct metal contact...
2017: Nature biomedical engineering
https://www.readbyqxmd.com/read/28801645/chronic-intermittent-hypobaric-hypoxia-improves-cardiac-function-through-inhibition-of-endoplasmic-reticulum-stress
#5
Fang Yuan, Li Zhang, Yan-Qing Li, Xu Teng, Si-Yu Tian, Xiao-Ran Wang, Yi Zhang
We investigated the role of endoplasmic reticulum stress (ERS) in chronic intermittent hypobaric hypoxia (CIHH)-induced cardiac protection. Adult male Sprague-Dawley rats were exposed to CIHH treatment simulating 5000 m altitude for 28 days, 6 hours per day. The heart was isolated and perfused with Langendorff apparatus and subjected to 30-min ischemia followed by 60-min reperfusion. Cardiac function, infarct size, and lactate dehydrogenase (LDH) activity were assessed. Expression of ERS molecular chaperones (GRP78, CHOP and caspase-12) was assayed by western blot analysis...
August 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28801595/spectral-characteristics-of-voltage-sensitive-indocyanine-green-fluorescence-in-the-heart
#6
Regina Mačianskienė, Mantė Almanaitytė, Rimantas Treinys, Antanas Navalinskas, Rimantas Benetis, Jonas Jurevičius
Indocyanine green (ICG) fluorescent dye has been approved by the FDA for use in medical diagnostics. Recently, we demonstrated that ICG dye has voltage-sensitive properties with a dual-component (fast and slow) response in the Langendorff-perfused rabbit heart. Here, we extended our studies by showing the different spectral properties of both components for analysis of the fractional change in ICG fluorescence in response to voltage changes. We used light from four LEDs to obtain excitation; emission was measured using an EMCCD camera with band-pass filters and a spectrometer...
August 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28801038/qrs-duration-reflects-underlying-changes-in-conduction-velocity-during-increased-intraventricular-pressure-and-heart-failure
#7
REVIEW
Jorge G Quintanilla, Javier Moreno, Tamara Archondo, José Manuel Alfonso-Almazán, José María Lillo-Castellano, Elena Usandizaga, María Jesús García-Torrent, Cruz Rodríguez-Bobada, Pablo González, Luis Borrego, Victoria Cañadas-Godoy, Juan J González-Ferrer, Nicasio Pérez-Castellano, Julián Pérez-Villacastín, David Filgueiras-Rama
Pressure overload and heart failure electrophysiological remodeling (HF-ER) in pigs are associated with decreased conduction velocity (CV) and dispersion of repolarization, which lead to higher risk of ventricular arrhythmia. This work aimed to establish the correlation between QRS complex duration and underlying changes in CV during increased intraventricular pressure (IVP) and/or HF-ER ex-vivo, and to determine whether QRS duration could be sensitive to an acute increase in left ventricular afterload in-vivo...
August 8, 2017: Progress in Biophysics and Molecular Biology
https://www.readbyqxmd.com/read/28780600/the-anti-influenza-drug-oseltamivir-reduces-atrial-fibrillation-in-an-experimental-whole-heart-model
#8
Gerrit Frommeyer, André Mittelstedt, Julian Wolfes, Christian Ellermann, Simon Kochhäuser, Patrick Leitz, Dirk G Dechering, Lars Eckardt
Recent experimental studies suggested direct effects of the anti-influenza drug oseltamivir on cardiac electrophysiology. We therefore aimed at analyzing potential antiarrhythmic effects of oseltamivir on atrial fibrillation (AF) in an experimental whole-heart model. Twelve rabbit hearts were isolated and Langendorff perfused. Thereafter, hearts were paced at cycle lengths of 350, 250, and 200 ms in the atrium. A standardized protocol employing atrial burst pacing induced AF in 4 of 12 hearts under baseline conditions (33%, 11 episodes)...
August 6, 2017: Naunyn-Schmiedeberg's Archives of Pharmacology
https://www.readbyqxmd.com/read/28766171/cisplatin-and-cisplatin-analogues-perfusion-through-isolated-rat-heart-the-effects-of-acute-application-on-oxidative-stress-biomarkers
#9
Isidora M Stojic, Vladimir I Zivkovic, Ivan M Srejovic, Tamara R Nikolic, Nevena S Jeremic, Jovana N Jeremic, Dragan M Djuric, Nemanja Jovicic, Katarina G Radonjic, Zivadin D Bugarcic, Vladimir L J Jakovljevic, Slobodan S Novokmet
Drug-induced oxidative stress can occur in numerous tissues and organ systems (liver, kidney, ear, nervous system, and cardiovascular system). Cancer therapy with cisplatin is associated with side effects to which oxidative stress may contribute. We have compared the influences of cisplatin (reference compound) and its' analogues (dichloro(1,2-diaminocyclohexane)platinum(II) and chloro(2,2':6',2″-terpyridine)platinum(II)) in a model of isolated rat heart using the Langendorff technique. The production of oxidative stress biomarkers, antioxidant enzymes, myocardial damage, and expression of Bax, OH-1, and SODs were studied...
August 1, 2017: Molecular and Cellular Biochemistry
https://www.readbyqxmd.com/read/28758595/vasodilator-effect-of-angiotensin-1-7-on-vascular-coronary-bed-of-rats-role-of-mas-ace-and-ace2
#10
Patrícia Lanza Moraes, Lucas Miranda Kangussu, Carlos Henrique Castro, Robson As Santos, Anderson José Ferreira, Alvair P Almeida
Angiotensin(Ang)-(1-7) is a biologically active member of the renin-angiotensin system that participates of the regulation of blood pressure. Although Ang-(1-7) is able to potentiate the vasodilator effect of bradykinin in coronary bed of rats, a direct vasodilator effect of Ang-(1-7) in this vascular bed has not been characterized. Thus, the aim of this study was to evaluate the mechanisms involved in the vasodilator effect of Ang-(1-7) in the vasculature of isolated rat hearts perfused according to the Langendorff technique at constant flow...
July 28, 2017: Protein and Peptide Letters
https://www.readbyqxmd.com/read/28758414/modulation-of-n-methyl-d-aspartate-receptors-in-isolated-rat-heart
#11
Ivan M Srejovic, Vladimir I Zivkovic, Tamara R Nikolic, Nevena Jeremic, Isidora Stojic, Jovana Jeremic, Dragan Djuric, Vladimir Jakovljevic
Considering the limited data about the role of N-methyl-D-aspartate receptors (NMDA-R) in cardiovascular system and heart, the aim of the present study was to examine the effects of NMDA and DL-homocysteine thiolacotne (DL-Hcy TLHC), alone and in combinations with glycine, memantine and ifenprodil, in the isolated rat heart. The hearts of Wistar albino rats were retrogradely perfused according to the Langendorff technique at a constant perfusion pressure. The experimental protocol for all experimental groups included the stabilization period, application of estimated substance in duration of 5 minutes, followed by wash-out period in duration of 10 minutes...
July 30, 2017: Canadian Journal of Physiology and Pharmacology
https://www.readbyqxmd.com/read/28755986/investigating-the-involvement-of-glycogen-synthase-kinase-3%C3%AE-and-gap-junction-signaling-in-trpv1-and-remote-hind-preconditioning-induced-cardioprotection
#12
Puneet Kaur Randhawa, Amteshwar Singh Jaggi
Remote ischemic preconditioning (RIPC) is the phenomenon that harnesses the body's endogenous protective mechanisms against prolonged ischemia-reperfusion-induced injury. The present study aimed to explore the involvement of glycogen synthase kinase-3β and gap junction signaling in TRPV1 and remote hind preconditioning-induced cardioprotection. In the present study, four consecutive cycles (5min of ischemia-reperfusion) of remote hind limb preconditioning stimulus were delivered using a blood pressure cuff fastened at the inguinal level of the rat...
July 27, 2017: European Journal of Pharmacology
https://www.readbyqxmd.com/read/28743285/%C3%AE-adrenergic-receptor-camp-pka-signaling-contributes-to-the-intracellular-ca-2-release-by-tentacle-extract-from-the-jellyfish-cyanea-capillata
#13
Qianqian Wang, Hui Zhang, Bo Wang, Chao Wang, Liang Xiao, Liming Zhang
BACKGROUND: Intracellular Ca(2+) overload induced by extracellular Ca(2+) entry has previously been confirmed to be an important mechanism for the cardiotoxicity as well as the acute heart dysfunction induced by jellyfish venom, while the underlying mechanism remains to be elucidated. METHODS: Under extracellular Ca(2+)-free or Ca(2+)-containing conditions, the Ca(2+) fluorescence in isolated adult mouse cardiomyocytes pre-incubated with tentacle extract (TE) from the jellyfish Cyanea capillata and β blockers was scanned by laser scanning confocal microscope...
July 25, 2017: BMC Pharmacology & Toxicology
https://www.readbyqxmd.com/read/28733433/intensive-exercise-training-improves-cardiac-electrical-stability-in-myocardial-infarcted-rats
#14
Horesh Dor-Haim, Chaim Lotan, Michal Horowitz, Moshe Swissa
BACKGROUND: Moderate exercise training has been shown to decrease sudden cardiac death post myocardial infarction. However, the effects of intensive exercise are still controversial. METHODS AND RESULTS: Fourteen myocardial-infarcted rats were divided into sedentary (n=8) and intensive training groups (n=6) and 18 sham control rats to sedentary (n=10) and intensive training groups (n=8). Heart rate variability was obtained at weeks 1 and 8. The inducibility of ventricular tachycardia/fibrillation was assessed in a Langendorff system...
July 21, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/28730389/cardiovascular-effects-of-high-molecular-weight-compounds-of-humic-nature
#15
M V Zykova, M V Belousov, T V Lasukova, A S Gorbunov, L A Logvinova, A M Dygai
The active ingredient extracted from the peat humic substances was characterized by physicochemical parameters evaluated by UV- and IR-spectroscopy, titration, and elemental (C, H, N) analysis. The cardiovascular effects of this ingredient were examined on isolated Langendorff-perfused rat heart. It was found that the active substance in a concentration range of 0.01-0.1 mg/ml produced a vasodilating effect; in addition, it decreased the end-diastolic and left-ventricular developed pressures.
June 2017: Bulletin of Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28725491/ds16570511-is-a-small-molecule-inhibitor-of-the-mitochondrial-calcium-uniporter
#16
Naohiro Kon, Michiko Murakoshi, Aya Isobe, Katsuji Kagechika, Naoki Miyoshi, Takahiro Nagayama
In cardiac myocytes, regulation of mitochondrial Ca(2+) is important for cellular signaling and cardiac contraction. Ca(2+) entry into the mitochondria is mediated by a highly selective Ca(2+) channel called the mitochondrial calcium uniporter, which consists of a pore-forming subunit MCU and regulatory subunits such as MICU1. Although pharmacological regulation of the mitochondrial Ca(2+) influx is a promising approach to controlling the cellular functions, a cell-permeable and specific inhibitor of the mitochondrial calcium uniporter has not yet been developed...
2017: Cell Death Discovery
https://www.readbyqxmd.com/read/28721162/the-influence-of-rapamycin-on-the-early-cardioprotective-effect-of-hypoxic-preconditioning-on-cardiomyocytes
#17
Jiang Wang, YiLiyaer Maimaitili, Hong Zheng, Jin Yu, Hai Guo, Hai-Ping Ma, Chun-Ling Chen
INTRODUCTION: The purpose of this study was to examine the effects of rapamycin on the cardioprotective effect of hypoxic preconditioning (HPC) and on the mammalian target of rapamycin (mTOR)-mediated hypoxia-inducible factor 1 (HIF-1) signaling pathway. MATERIAL AND METHODS: Primary cardiomyocytes were isolated from rat pups and underwent rapamycin and/or HPC, followed by hypoxia/re-oxygenation (H/R) injury. Cell viability and cell injury were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays, and qRT-PCR was used to measure HIF-1α and mTOR mRNA expression...
June 2017: Archives of Medical Science: AMS
https://www.readbyqxmd.com/read/28707739/angiotensin-ii-preconditioning-is-associated-with-increased-pkc%C3%AE%C2%B5-pkc%C3%AE-ratio-and-prosurvival-kinases-in-mitochondria
#18
Rebeca E Nuñez, Sabzali Javadov, Nelson Escobales
Angiotensin II preconditioning (APC) has been shown to reproduce the cardioprotective effects of ischaemic preconditioning (IPC), however, molecular mechanisms mediating the effects of APC remain unknown. In this study, Langendorff-perfused rat hearts were subjected to IPC, APC or both (IPC/APC) followed by ischaemia-reperfusion (IR), to determine translocation of PKCε, PKCδ, Akt, Erk1/2, JNK, p38 MAPK and GSK-3β to mitochondria as an indicator of activation of the protein kinases. In agreement with previous observations, IPC, APC and IPC/APC increased the recovery of left ventricular developed pressure (LVDP), reduced infarct size (IS) and lactate dehydrogenase (LDH) release, compared to controls...
July 14, 2017: Clinical and Experimental Pharmacology & Physiology
https://www.readbyqxmd.com/read/28692548/comparison-of-vernakalant-and-ranolazine-in-atrial-fibrillation
#19
Gerrit Frommeyer, Magdalena Sterneberg, Dirk G Dechering, Simon Kochhäuser, Nils Bögeholz, Michael Fehr, Lars Eckardt
BACKGROUND: Current guidelines recommend vernakalant for pharmacologic cardioversion of recent-onset atrial fibrillation. However, this drug is not established as chronic therapy. METHODS AND RESULTS: In total, 15 rabbit hearts were Langendorff-perfused. A burst pacing protocol-induced atrial fibrillation in 7 of 15 hearts at baseline (10 episodes). Subsequently, a combination of acetylcholine and isoproterenol (ACH/ISO) has been administered to increase occurrence of atrial fibrillation resulting in a reduction of atrial action potential duration (-25 ms, P < 0...
September 2017: Journal of Cardiovascular Medicine
https://www.readbyqxmd.com/read/28690215/-role-of-melatonin-in-calcium-overload-induced-heart-injury
#20
Lingheng Kong, Ming Wei, Na Sun, Juanxia Zhu, Xingli Su
To investigate the role of melatonin in calcium overload-induced heart injury.
 Methods: Thirty-two rats were divided into 4 groups: a control group (Control), a melatonin control group (Mel), a calcium overload group (CaP), and a calcium overload plus melatonin group (Mel+CaP). Isolated Sprague Dawley male rat hearts underwent Langendorff perfusion. Left ventricular developed pressure (LVDP) was calculated to evaluate the myocardial performance. Triphenyltetrazolium chloride staining was used to measure the infarct size of myocardium...
June 28, 2017: Zhong Nan da Xue Xue Bao. Yi Xue Ban, Journal of Central South University. Medical Sciences
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