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https://www.readbyqxmd.com/read/28324970/development-of-data-acquisition-components-for-simultaneous-recording-of-3d-epicardial-and-surface-ecg-signals-in-the-langendorff-perfusion-apparatus
#1
Ryan Wade Selby, Anup Jonchhe, Chen Kaplan, Coeli M Lopes, Behnaz Ghoraani
Sudden Cardiac Death (SCD) claims 7 million lives per year. The importance of myocardial electrogram (EGM) repolarization alternans and surface electrocardiogram (ECG) T-wave alternans is gaining traction for understanding the underlying SCD mechanisms. However, the relationship between the 3D spatial distribution of myocardial EGMs and surface ECG with respect to SCD has yet to be investigated. To make this happen, a modified data acquisition system has been developed and fabricated in conjunction with the Langendorff perfusion system to enable simultaneous recording and analysis of the 3D spatial distribution of myocardial EGMs and the surface ECG...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28316073/arrhythmic-effects-of-epac-mediated-ryanodine-receptor-activation-in-langendorff-perfused-murine-hearts-are-associated-with-reduced-conduction-velocity
#2
Mengye Li, Sandeep Hothi, Samantha C Salvage, Kamalan Jeevaratnam, Andrew A Grace, Christopher L-H Huang
Recent papers have attributed arrhythmic substrate in murine RyR2-P2328S hearts to reduced action potential (AP) conduction velocities (CV), reflecting acute functional inhibition and/or reduced expression of sodium channels. We explored for acute effects of direct Epac (exchange protein directly activated by cAMP)-mediated ryanodine receptor-2 (RyR2) activation on arrhythmic substrate and CV. Monophasic action potential recordings demonstrated that initial steady (8-Hz) extrinsic pacing elicited ventricular tachycardia (VT) in 0 of 18 Langendorff-perfused wild-type mouse ventricles before pharmacological intervention...
March 18, 2017: Clinical and Experimental Pharmacology & Physiology
https://www.readbyqxmd.com/read/28314848/effects-of-late-sodium-current-blockade-on-ventricular-refibrillation-in-a-rabbit-model
#3
Mohammed Ali Azam, Nima Zamiri, Stéphane Massé, Marjan Kusha, Patrick F H Lai, Govind K Nair, Nigel S Tan, Christopher Labos, Kumaraswamy Nanthakumar
BACKGROUND: After defibrillation of initial ventricular fibrillation (VF), it is crucial to prevent refibrillation to ensure successful resuscitation outcomes. Inability of the late Na(+) current to inactivate leads to intracellular Ca(2+) dysregulation and arrhythmias. Our aim was to determine the effects of ranolazine and GS-967, inhibitors of the late Na(+) current, on ventricular refibrillation. METHODS AND RESULTS: Long-duration VF was induced electrically in Langendorff-perfused rabbit hearts (n=22) and terminated with a defibrillator after 6 minutes...
March 2017: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/28299825/fingolimod-gilenya-%C3%A2-in-multiple-sclerosis-bradycardia-atrioventricular-blocks-and-mild-effect-on-the-qtc-interval-something-to-do-with-the-l-type-calcium-channel
#4
Sylvie Pilote, Chantale Simard, Benoit Drolet
Cardiac arrhythmias and ECG abnormalities including bradycardia, prolongation of the QT interval and atrioventricular (AV) conduction blocks have been extensively observed with fingolimod, the first marketed oral drug for treating the relapsing-remitting form of multiple sclerosis. The present study was aiming to further elucidate the effects of fingolimod on cardiac electrophysiology at three different levels; 1) in vitro, 2) ex vivo and 3) in vivo. 1) Patch-clamp experiments in whole cell configuration were performed on Cav 1...
March 16, 2017: Fundamental & Clinical Pharmacology
https://www.readbyqxmd.com/read/28296232/inhibitors-of-soluble-epoxide-hydrolase-minimize-ischemia-reperfusion-induced-cardiac-damage-in-normal-hypertensive-and-diabetic-rats
#5
Oliul Islam, Prashanth Patil, Sumanta K Goswami, Rema Razdan, Mohammed N Inamdar, Mohammed Rizwan, Jubin Mathew, Bora Inceoglu, Kin S Stephen Lee, Sung H Hwang, Bruce D Hammock
AIM: We designed a study to evaluate the cardioprotective effect of two soluble epoxide hydrolase (sEH) inhibitors, 1-(1-propanoylpiperidin-4-yl)-3-(4-trifluoromethoxy)phenyl)urea (TPPU) and trans-4-{4-[3-(4-trifluoromethoxyphenyl)-ureido]cyclohexyloxy}benzoic acid (t-TUCB), in ischemia-reperfusion (IR) model. METHODS: Cardioprotective effects of the sEH inhibitors were evaluated against IR-induced myocardial damage in hearts from normal, hypertensive and diabetic rats using Langendorff's apparatus...
March 15, 2017: Cardiovascular Therapeutics
https://www.readbyqxmd.com/read/28290047/adaptation-to-chronic-continuous-hypoxia-potentiates-akt-hk2-anti-apoptotic-pathway-during-brief-myocardial-ischemia-reperfusion-insult
#6
David Kolar, Milada Gresikova, Petra Waskova-Arnostova, Barbara Elsnicova, Jana Kohutova, Daniela Hornikova, Pavel Vebr, Jan Neckar, Tereza Blahova, Dita Kasparova, Jiri Novotny, Frantisek Kolar, Olga Novakova, Jitka M Zurmanova
Adaptation to chronic hypoxia represents a potential cardioprotective intervention reducing the extent of acute ischemia/reperfusion (I/R) injury, which is a major cause of death worldwide. The main objective of this study was to investigate the anti-apoptotic Akt/hexokinase 2 (HK2) pathway in hypoxic hearts subjected to I/R insult. Hearts isolated from male Wistar rats exposed either to continuous normobaric hypoxia (CNH; 10% O2) or to room air for 3 weeks were perfused according to Langendorff and subjected to 10 min of no-flow ischemia and 10 min of reperfusion...
March 13, 2017: Molecular and Cellular Biochemistry
https://www.readbyqxmd.com/read/28282374/depletion-of-cardiac-catecholamine-stores-impairs-cardiac-norepinephrine-re-uptake-by-downregulation-of-the-norepinephrine-transporter
#7
Michael M Kreusser, Lorenz H Lehmann, Markus Haass, Sebastian J Buss, Hugo A Katus, Dirk Lossnitzer
In heart failure (HF), a disturbed cardiac norepinephrine (NE) homeostasis is characterized by depleted cardiac NE stores, impairment of the cardiac NE re-uptake by the neuronal norepinephrine transporter (NET) and enhanced cardiac NE net release. Reduced cardiac NE content appears to be caused by enhanced cardiac NE net release from sympathetic neurons in HF, triggered by neurohumoral activation. However, it remains unclear whether reduced NE itself has an impact on cardiac NE re-uptake, independent of neurohumoral activation...
2017: PloS One
https://www.readbyqxmd.com/read/28278587/functionality-of-albumin-derived-perfluorocarbon-based-artificial-oxygen-carriers-in-the-langendorff-heart-%C3%A2
#8
Anna Wrobeln, Klaus D Schlüter, Jürgen Linders, Manfred Zähres, Christian Mayer, Michael Kirsch, Katja B Ferenz
The aim of this study was to prove whether albumin-derived perfluorocarbon-based nanoparticles (capsules) can operate as a novel artificial oxygen carrier in a rat Langendorff-heart perfusion model. Hearts perfused with capsules showed increased left ventricular pressure and rate pressure product compared to hearts perfused with pure Krebs-Henseleit (KH)-buffer. The capsules prevented the myocardium from functional fail when in their absence a noxious ischemia was observed. Capsules did not change rheological properties of KH-buffer and could repeatedly reload with oxygen...
February 8, 2017: Artificial Cells, Nanomedicine, and Biotechnology
https://www.readbyqxmd.com/read/28277663/development-of-fluorinated-analogues-of-perhexiline-with-improved-pharmacokinetic-properties-and-retained-efficacy
#9
Chih-Chung Tseng, Hannah Noordali, Monica Sani, Melanie Madhani, Denis M Grant, Michael P Frenneaux, Matteo Zanda, Iain R Greig
We designed and synthesized perhexiline analogues that have the same therapeutic profile as the parent cardiovascular drug but lacking its metabolic liability associated with CYP2D6 metabolism. Cycloalkyl perhexiline analogues 6a-j were found to be unsuitable for further development, as they retained a pharmacokinetic profile very similar to that shown by the parent compound. Multistep synthesis of perhexiline analogues incorporating fluorine atoms onto the cyclohexyl ring(s) provided a range of different fluoroperhexiline analogues...
March 21, 2017: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28276718/insulin-and-gsk3%C3%AE-inhibition-abrogates-the-infarct-sparing-effect-of-ischemic-postconditioning-in-ex-vivo-rat-hearts
#10
Erik Helgeland, Anita Wergeland, Rune M Sandøy, Maren Askeland, Anne Aspevik, Lars Breivik, Anne K Jonassen
OBJECTIVES: Pharmacological treatment of reperfusion injury using insulin and GSK3β inhibition has been shown to be cardioprotective, however, their interaction with the endogenous cardioprotective strategy, ischemic postconditioning, is not known. DESIGN: Langendorff perfused ex vivo rat hearts were subjected to 30 min of regional ischemia and 120 min of reperfusion. For the first 15 min of reperfusion hearts received either vehicle (Ctr), insulin (Ins) or a GSK3β inhibitor (SB415286; SB41), with or without interruption of ischemic postconditioning (IPost; 3 × 30 s of global ischemia)...
February 13, 2017: Scandinavian Cardiovascular Journal: SCJ
https://www.readbyqxmd.com/read/28269065/development-of-matlab-software-to-control-data-acquisition-from-a-multichannel-systems-multi-electrode-array
#11
Erik Messier
A Multichannel Systems (MCS) microelectrode array data acquisition (DAQ) unit is used to collect multichannel electrograms (EGM) from a Langendorff perfused rabbit heart system to study sudden cardiac death (SCD). MCS provides software through which data being processed by the DAQ unit can be displayed and saved, but this software's combined utility with MATLAB is not very effective. MCSs software stores recorded EGM data in a MathCad (MCD) format, which is then converted to a text file format. These text files are very large, and it is therefore very time consuming to import the EGM data into MATLAB for real-time analysis...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268301/pro-arrhythmic-effect-of-heart-rate-variability-during-periodic-pacing
#12
Kanchan Kulkarni, Steven W Lee, Elena G Tolkacheva
Clinically, healthy hearts have been associated with a high ventricular heart rate variability (HRV) while diseased hearts have been known to exhibit low ventricular HRV. Hence, low HRV is suggested to be a marker of cardiac ventricular arrhythmias. Over the past few years, there has been considerable amount of interest in incorporating HRV in pacing to emulate healthy heart conditions and re-stabilize the electrical activity in diseased hearts. Recently, we used single cell numerical simulations to demonstrate that HRV incorporated into periodic pacing promotes alternans formation and thus, can be pro-arrhythmic...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28265681/ischemia-induced-drp1-and-fis1-mediated-mitochondrial-fission-and-right-ventricular-dysfunction-in-pulmonary-hypertension
#13
Lian Tian, Monica Neuber-Hess, Jeffrey Mewburn, Asish Dasgupta, Kimberly Dunham-Snary, Danchen Wu, Kuang-Hueih Chen, Zhigang Hong, Willard W Sharp, Shelby Kutty, Stephen L Archer
Right ventricular (RV) function determines prognosis in pulmonary arterial hypertension (PAH). We hypothesize that ischemia causes RV dysfunction in PAH by triggering dynamin-related protein 1 (Drp1)-mediated mitochondrial fission. RV function was compared in control rats (n = 50) versus rats with monocrotaline-induced PAH (MCT-PAH; n = 60) both in vivo (echocardiography) and ex vivo (RV Langendorff). Mitochondrial membrane potential and morphology and RV function were assessed before or after 2 cycles of ischemia-reperfusion injury challenge (RV-IR)...
March 6, 2017: Journal of Molecular Medicine: Official Organ of the "Gesellschaft Deutscher Naturforscher und Ärzte"
https://www.readbyqxmd.com/read/28258543/reducing-mitochondrial-bound-hexokinase-ii-mediates-transition-from-non-injurious-into-injurious-ischemia-reperfusion-of-the-intact-heart
#14
Rianne Nederlof, Ebru Gürel-Gurevin, Otto Eerbeek, Chaoqin Xie, G Sjoerd Deijs, Moritz Konkel, Jun Hu, Nina C Weber, Cees A Schumacher, Antonius Baartscheer, Egbert G Mik, Markus W Hollmann, Fadi G Akar, Coert J Zuurbier
Ischemia/reperfusion (I/R) of the heart becomes injurious when duration of the ischemic insult exceeds a certain threshold (approximately ≥20 min). Mitochondrial bound hexokinase II (mtHKII) protects against I/R injury, with the amount of mtHKII correlating with injury. Here, we examine whether mtHKII can induce the transition from non-injurious to injurious I/R, by detaching HKII from mitochondria during a non-injurious I/R interval. Additionally, we examine possible underlying mechanisms (increased reactive oxygen species (ROS), increased oxygen consumption (MVO2) and decreased cardiac energetics) associated with this transition...
March 3, 2017: Journal of Physiology and Biochemistry
https://www.readbyqxmd.com/read/28248537/effects-of-bepridil-on-stretch-activated-bkca-channels-and-stretch-induced-extrasystoles-in-isolated-chick-hearts
#15
Honghua Jin, Gentaro Iribe, Keiji Naruse
Various types of mechanosensitive ion channels, including cationic stretch-activated channels (SAC(NS)) and stretch-activated BKca (SAKca) channels, modulate heart rhythm. Bepridil has been used as an antiarrhythmic drug with multiple pharmacological effects; however, whether it is effective for mechanically induced arrhythmia has not been well investigated. To test the effects of Bepridil on SAKca channels activity, cultured chick embryonic ventricular myocytes were used for single-channel recordings. Bepridil significantly reduced the open probability of the SAKca channel (P(O))...
February 28, 2017: Physiological Research
https://www.readbyqxmd.com/read/28244203/decrease-in-long-chain-acylcarnitine-tissue-content-determines-the-duration-of-and-correlates-with-the-cardioprotective-effect-of-methyl-gbb
#16
Janis Kuka, Marina Makrecka-Kuka, Helena Cirule, Solveiga Grinberga, Eduards Sevostjanovs, Maija Dambrova, Edgars Liepinsh
Ischaemia in the heart is accompanied by the accumulation of long-chain acylcarnitines (LCACs) which is one of the multiple factors that contribute to the ischaemia-reperfusion damage development. Long-term pre-treatment that decreases carnitine and LCAC contents also reduces ischaemia-reperfusion (IR) damage; however, the duration of the post-treatment effects is not known. The aim of the study was to assess the post-treatment effects of the carnitine transport (OCTN2) inhibitor, methyl-GBB, on LCAC content and the duration of its cardioprotective effect...
February 28, 2017: Basic & Clinical Pharmacology & Toxicology
https://www.readbyqxmd.com/read/28240274/low-cost-optical-mapping-systems-for-panoramic-imaging-of-complex-arrhythmias-and-drug-action-in-translational-heart-models
#17
Peter Lee, Conrado J Calvo, José M Alfonso-Almazán, Jorge G Quintanilla, Francisco J Chorro, Ping Yan, Leslie M Loew, David Filgueiras-Rama, José Millet
Panoramic optical mapping is the primary method for imaging electrophysiological activity from the entire outer surface of Langendorff-perfused hearts. To date, it is the only method of simultaneously measuring multiple key electrophysiological parameters, such as transmembrane voltage and intracellular free calcium, at high spatial and temporal resolution. Despite the impact it has already had on the fields of cardiac arrhythmias and whole-heart computational modeling, present-day system designs precludes its adoption by the broader cardiovascular research community because of their high costs...
February 27, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28229626/the-role-of-hydrogen-sulfide-in-homocysteine-induced-cardiodynamic-effects-and-oxidative-stress-markers-in-the-isolated-rat-heart
#18
M Stojanovic, V Zivkovic, I Srejovic, V Jakovljevic, N Jeremic, D Djuric
This study aimed to assess the role of H2S in homocysteine-induced cardiodynamic effects in the isolated rat heart. The hearts were retrogradely perfused according to the Langendorff technique. The maximum and minimum rates of pressure in the left ventricle (dp/dt max, dp/dt min), systolic and diastolic left ventricular pressures (SLVP, DLVP), heart rate (HR), and coronary flow (CF) were measured. A spectrophotometrical method was used to measure the following oxidative stress markers: index of lipid peroxidation (thiobarbituric acid reactive substances, TBARS), nitrite level (NO2(-)), superoxide anion radicals (O2(•-)), and hydrogen peroxide (H2O2) concentrations...
December 2016: Physiol Int
https://www.readbyqxmd.com/read/28227282/development-of-matlab-software-to-control-data-acquisition-from-a-multichannel-systems-multi-electrode-array
#19
Erik Messier, Behnaz Ghoraani, Erik Messier, Erik Messier, Behnaz Ghoraani
A Multichannel Systems (MCS) microelectrode array data acquisition (DAQ) unit is used to collect multichannel electrograms (EGM) from a Langendorff perfused rabbit heart system to study sudden cardiac death (SCD). MCS provides software through which data being processed by the DAQ unit can be displayed and saved, but this software's combined utility with MATLAB is not very effective. MCSs software stores recorded EGM data in a MathCad (MCD) format, which is then converted to a text file format. These text files are very large, and it is therefore very time consuming to import the EGM data into MATLAB for real-time analysis...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227084/development-of-data-acquisition-components-for-simultaneous-recording-of-3d-epicardial-and-surface-ecg-signals-in-the-langendorff-perfusion-apparatus
#20
Ryan Wade Selby, Anup Jonchhe, Chen Kaplan, Coeli M Lopes, Behnaz Ghoraani, Ryan Wade Selby, Anup Jonchhe, Chen Kaplan, Coeli M Lopes, Behnaz Ghoraani, Chen Kaplan, Behnaz Ghoraani, Anup Jonchhe, Coeli M Lopes, Ryan Wade Selby
Sudden Cardiac Death (SCD) claims 7 million lives per year. The importance of myocardial electrogram (EGM) repolarization alternans and surface electrocardiogram (ECG) T-wave alternans is gaining traction for understanding the underlying SCD mechanisms. However, the relationship between the 3D spatial distribution of myocardial EGMs and surface ECG with respect to SCD has yet to be investigated. To make this happen, a modified data acquisition system has been developed and fabricated in conjunction with the Langendorff perfusion system to enable simultaneous recording and analysis of the 3D spatial distribution of myocardial EGMs and the surface ECG...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
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