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https://www.readbyqxmd.com/read/28822805/mg53-is-dispensable-for-t-tubule-maturation-but-critical-for-maintaining-t-tubule-integrity-following-cardiac-stress
#1
Caimei Zhang, Biyi Chen, Yihui Wang, Ang Guo, Yiqun Tang, Tahsin Khataei, Yun Shi, William J Kutschke, Kathy Zimmerman, Robert M Weiss, Jie Liu, Christopher J Benson, Jiang Hong, Jianjie Ma, Long-Sheng Song
The cardiac transverse (T)-tubule membrane system is the safeguard for cardiac function and undergoes dramatic remodeling in response to cardiac stress. However, the mechanism by which cardiomyocytes repair damaged T-tubule network remains unclear. In the present study, we tested the hypothesis that MG53, a muscle-specific membrane repair protein, antagonizes T-tubule damage to protect against maladaptive remodeling and thereby loss of excitation-contraction coupling and cardiac function. Using MG53-knockout (MG53-KO) mice, we first established that deficiency of MG53 had no impact on maturation of the T-tubule network in developing hearts...
August 16, 2017: Journal of Molecular and Cellular Cardiology
https://www.readbyqxmd.com/read/28818208/catecholamine-dependent-%C3%AE-adrenergic-signaling-in-a-pluripotent-stem-cell-model%C3%A2-of-takotsubo-cardiomyopathy
#2
Thomas Borchert, Daniela Hübscher, Celina I Guessoum, Tuan-Dinh D Lam, Jelena R Ghadri, Isabel N Schellinger, Malte Tiburcy, Norman Y Liaw, Yun Li, Jan Haas, Samuel Sossalla, Mia A Huber, Lukas Cyganek, Claudius Jacobshagen, Ralf Dressel, Uwe Raaz, Viacheslav O Nikolaev, Kaomei Guan, Holger Thiele, Benjamin Meder, Bernd Wollnik, Wolfram-Hubertus Zimmermann, Thomas F Lüscher, Gerd Hasenfuss, Christian Templin, Katrin Streckfuss-Bömeke
BACKGROUND: Takotsubo syndrome (TTS) is characterized by an acute left ventricular dysfunction and is associated with life-threating complications in the acute phase. The underlying disease mechanism in TTS is still unknown. A genetic basis has been suggested to be involved in the pathogenesis. OBJECTIVES: The aims of the study were to establish an in vitro induced pluripotent stem cell (iPSC) model of TTS, to test the hypothesis of altered β-adrenergic signaling in TTS iPSC-cardiomyocytes (CMs), and to explore whether genetic susceptibility underlies the pathophysiology of TTS...
August 22, 2017: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/28811222/antitussive-antispasmodic-bronchodilating-and-cardiac-inotropic-effects-of-the-essential-oil-from-blepharocalyx-salicifolius-leaves
#3
Jehison Jiménez Hernández, María Inés Ragone, Patricia Bonazzola, Arnaldo L Bandoni, Alicia E Consolini
ETHOPHARMACOLOGY RELEVANCE: Blepharocalyx salicifolius (Kunth) O. Berg (Myrtaceae) is a tree native to Argentina and Uruguay that grows and is cultivated along the riverside of the Rio de la Plata. The leaves of this plant species, locally known as "anacahuita" are used in South America to prepare infusions for the empiric treatment of cough and bronchospasm, as well as diarrhoea and other intestinal disorders. Although previous phytochemical studies have been performed with the essential oil extracted from Blepharocalyx salicifolius, pharmacological evidence supporting its traditional use is still lacking...
August 12, 2017: Journal of Ethnopharmacology
https://www.readbyqxmd.com/read/28803741/the-cardiovascular-toxicity-of-triadimefon-in-early-life-stage-of-zebrafish-and-potential-implications-to-human-health
#4
Hong-Cui Liu, Tian-Yi Chu, Li-Li Chen, Wen-Jun Gui, Guo-Nian Zhu
The health risk of triadimefon (TF) to cardiovascular system of human is still unclear, especially to pesticide suicides population, occupational population (farmers, retailers and pharmaceutical workers), and special population (young children and infants, pregnant women, older people, and those with compromised immune systems) who are at a greater risk. Therefore, firstly we explored the toxic effects and possible mechanism of cardiovascular toxicity induced by TF using zebrafish model. Zebrafish at stage of 48 h post fertilization (hpf) exposed to TF for 24 h exhibited morphological malformations which were further confirmed by histopathologic examination, including pericardial edema, circulation abnormalities, serious venous thrombosis and increased distance between the sinus venosus (SV) and bulbus arteriosus (BA) regions of the heart...
August 10, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28770696/left-main-coronary-artery-atresia-in-a-child-a-case-report-and-review-of-the-literature
#5
Tomohiro Hayashi, Kenji Waki, Yoshio Arakaki
Congenital atresia of the left coronary artery is a very rare condition. We report a case of a 13-year-old boy who was followed-up at our outpatient clinic from 6 months of age because of heart murmur. He had no symptoms for more than 10 years, and his left ventricular contraction was normal. Exercise electrocardiogram was performed at 7 and 10 years of age, and ST depression was not observed. He presented with chest pain and syncope on exertion at the ages of 11 and 12 years, respectively, and ST depression on exercise electrocardiogram was detected for the first time at 13 years of age...
August 3, 2017: Cardiology in the Young
https://www.readbyqxmd.com/read/28757442/endothelin-receptor-mediated-ca-2-signaling-in-coronary-arteries-after-experimentally-induced-ischemia-reperfusion-injury-in-rat
#6
Sarah Brøgger Kristiansen, Kristian A Haanes, Majid Sheykhzade, Lars Edvinsson
BACKGROUND: Acute myocardial infarction is one of the leading causes of death. It is caused by a blockage of a coronary artery leading to reduced blood flow to the myocardium and hence ischemic damage. In addition, a second wave of damage after the flow has been restored, named reperfusion injury greatly exacerbate the damage. For the latter, no medical treatment exist. In this study the aim was to characterize Ca(2+) sensitivity in coronary arteries following experimental ischemia/reperfusion injury...
July 27, 2017: Journal of Molecular and Cellular Cardiology
https://www.readbyqxmd.com/read/28738671/inertial-flywheel-resistance-training-and-muscle-oxygen-saturation
#7
Rafael Timón, Jesús G Ponce-González, José L González-Montesinos, Guillermo Olcina, Alejandro Pérez-Pérez, José Castro-Piñero
BACKGROUND: The inertial flywheel device causes an increase in eccentric overload during training. The aim was to study muscle oxygen saturation produced during an inertial flywheel squat training, comparing it with a barbell squat training. METHODS: Twelve male adults performed a barbell squat training (3 x 8 reps, 75-80% 1RM) and a flywheel squat training (3 x 8 reps, all-out). Muscle oxygen saturation (%SmO2), total hemoglobin (tHb), reoxygenation, heart rate (HR), lactate, vertical jumps, maximal voluntary isometric contraction and rated perceived exertion (RPE) were studied...
July 24, 2017: Journal of Sports Medicine and Physical Fitness
https://www.readbyqxmd.com/read/28734932/a-pyridone-derivative-activates-serca2a-by-attenuating-the-inhibitory-effect-of-phospholamban
#8
Manami Kaneko, Hisato Yamamoto, Hiroki Sakai, Yusuke Kamada, Toshiki Tanaka, Shuji Fujiwara, Synsuke Yamamoto, Hiroki Takahagi, Hideyuki Igawa, Shizuo Kasai, Masakuni Noda, Makoto Inui, Tomoyuki Nishimoto
The cardiac sarco/endoplasmic reticulum Ca(2+)-dependent ATPase 2a (SERCA2a) plays a central role in Ca(2+) handling within cardiomyocytes and is negatively regulated by phospholamban (PLN), a sarcoplasmic reticulum (SR) membrane protein. The activation of SERCA2a, which has been reported to improve cardiac dysfunction in heart failure, is a potential therapeutic approach for heart failure. Therefore, we developed a novel small molecule, compound A and characterized it both in vitro and in vivo. Compound A activated the Ca(2+)-dependent ATPase activity of cardiac SR vesicles but not that of skeletal muscle SR vesicles that lack PLN...
July 19, 2017: European Journal of Pharmacology
https://www.readbyqxmd.com/read/28721030/regular-physical-exercise-improves-cardiac-autonomic-and-muscle-vasodilatory-responses-to-isometric-exercise-in-healthy-elderly
#9
Adriana de Oliveira Sarmento, Amilton da Cruz Santos, Ivani Credidio Trombetta, Marciano Moacir Dantas, Ana Cristina Oliveira Marques, Leone Severino do Nascimento, Bruno Teixeira Barbosa, Marcelo Rodrigues Dos Santos, Maria do Amparo Andrade, Anna Myrna Jaguaribe-Lima, Maria do Socorro Brasileiro-Santos
The objective of this study was to evaluate cardiac autonomic control and muscle vasodilation response during isometric exercise in sedentary and physically active older adults. Twenty healthy participants, 10 sedentary and 10 physically active older adults, were evaluated and paired by gender, age, and body mass index. Sympathetic and parasympathetic cardiac activity (spectral and symbolic heart rate analysis) and muscle blood flow (venous occlusion plethysmography) were measured for 10 minutes at rest (baseline) and during 3 minutes of isometric handgrip exercise at 30% of the maximum voluntary contraction (sympathetic excitatory maneuver)...
2017: Clinical Interventions in Aging
https://www.readbyqxmd.com/read/28720715/ischemic-preconditioning-does-not-alter-muscle-sympathetic-responses-to-static-handgrip-and-metaboreflex-activation-in-young-healthy-men
#10
Anthony V Incognito, Connor J Doherty, Jordan B Lee, Matthew J Burns, Philip J Millar
Ischemic preconditioning (IPC) has been hypothesized to elicit ergogenic effects by reducing feedback from metabolically sensitive group III/IV muscle afferents during exercise. If so, reflex efferent neural outflow should be attenuated. We investigated the effects of IPC on muscle sympathetic nerve activity (MSNA) during static handgrip (SHG) and used post-exercise circulatory occlusion (PECO) to isolate for the muscle metaboreflex. Thirty-seven healthy men (age: 24 ± 5 years [mean ± SD]) were randomized to receive sham (n = 16) or IPC (n = 21) interventions...
July 2017: Physiological Reports
https://www.readbyqxmd.com/read/28717924/hypertrophic-cardiomyopathy-and-the-myosin-mesa-viewing-an-old-disease-in-a-new-light
#11
REVIEW
Darshan V Trivedi, Arjun S Adhikari, Saswata S Sarkar, Kathleen M Ruppel, James A Spudich
The sarcomere is an exquisitely designed apparatus that is capable of generating force, which in the case of the heart results in the pumping of blood throughout the body. At the molecular level, an ATP-dependent interaction of myosin with actin drives the contraction and force generation of the sarcomere. Over the past six decades, work on muscle has yielded tremendous insights into the workings of the sarcomeric system. We now stand on the cusp where the acquired knowledge of how the sarcomere contracts and how that contraction is regulated can be extended to an understanding of the molecular mechanisms of sarcomeric diseases, such as hypertrophic cardiomyopathy (HCM)...
July 17, 2017: Biophysical Reviews
https://www.readbyqxmd.com/read/28717163/titin-mediated-thick-filament-activation-through-a-mechanosensing-mechanism-introduces-sarcomere-length-dependencies-in-mathematical-models-of-rat-trabecula-and-whole-ventricle
#12
Lorenzo Marcucci, Takumi Washio, Toshio Yanagida
Recent experimental evidence in skeletal muscle demonstrated the existence of a thick-filament mechanosensing mechanism, acting as a second regulatory system for muscle contraction, in addition to calcium-mediated thin filament regulation. These two systems cooperate to generate force, but the extent to which their interaction is relevant in physiologically contracting muscle was not yet assessed experimentally. Therefore, we included both regulatory mechanisms in a mathematical model of rat trabecula and whole ventricle...
July 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28706255/mitsugumin-29-regulates-t-tubule-architecture-in-the-failing-heart
#13
Robert N Correll, Jeffrey M Lynch, Tobias G Schips, Vikram Prasad, Allen J York, Michelle A Sargent, Didier X P Brochet, Jianjie Ma, Jeffery D Molkentin
Transverse tubules (t-tubules) are uniquely-adapted membrane invaginations in cardiac myocytes that facilitate the synchronous release of Ca(2+) from internal stores and subsequent myofilament contraction, although these structures become disorganized and rarefied in heart failure. We previously observed that mitsugumin 29 (Mg29), an important t-tubule organizing protein in skeletal muscle, was induced in the mouse heart for the first time during dilated cardiomyopathy with heart failure. Here we generated cardiac-specific transgenic mice expressing Mg29 to model this observed induction in the failing heart...
July 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28699532/modulation-of-heart-rate-by-acute-or-chronic-aerobic-exercise-potential-effects-on-blood-pressure-control
#14
Carme Perez-Quilis, J Derek Kingsley, Kabir Malkani, Gianfranco Cervellin, Giuseppe Lippi, Fabian Sanchis-Gomar
It was initially assumed that heart rate and arterial blood pressure were modulated by normal respiration and muscle contraction. The arterial baroreflex, an inverse relationship between blood pressure and heart rate, was later reported. Nonetheless, it was then assumed that those responses involved vagal modulation. We summarize available evidence on the modulation of heart rate by acute or chronic aerobic exercise as well as its potential implications on BP control. Numerous studies have tried to clarify whether aerobic exercise modifies neurally-mediated vasoconstriction, but they report contradictory results...
July 10, 2017: Current Pharmaceutical Design
https://www.readbyqxmd.com/read/28698364/loss-of-mouse-cardiomyocyte-talin-1-and-talin-2-leads-to-%C3%AE-1-integrin-reduction-costameric-instability-and-dilated-cardiomyopathy
#15
Ana Maria Manso, Hideshi Okada, Francesca M Sakamoto, Emily Moreno, Susan J Monkley, Ruixia Li, David R Critchley, Robert S Ross
Continuous contraction-relaxation cycles of the heart require strong and stable connections of cardiac myocytes (CMs) with the extracellular matrix (ECM) to preserve sarcolemmal integrity. CM attachment to the ECM is mediated by integrin complexes localized at the muscle adhesion sites termed costameres. The ubiquitously expressed cytoskeletal protein talin (Tln) is a component of muscle costameres that links integrins ultimately to the sarcomere. There are two talin genes, Tln1 and Tln2. Here, we tested the function of these two Tln forms in myocardium where Tln2 is the dominant isoform in postnatal CMs...
July 25, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28694237/phase-transitions-during-compression-and-decompression-of-clots-from-platelet-poor-plasma-platelet-rich-plasma-and-whole-blood
#16
Xiaojun Liang, Irina Chernysh, Prashant K Purohit, John W Weisel
Blood clots are required to stem bleeding and are subject to a variety of stresses, but they can also block blood vessels and cause heart attacks and ischemic strokes. We measured the compressive response of human platelet-poor plasma (PPP) clots, platelet-rich plasma (PRP) clots and whole blood clots and correlated these measurements with confocal and scanning electron microscopy to track changes in clot structure. Stress-strain curves revealed four characteristic regions, for compression-decompression: (1) linear elastic region; (2) upper plateau or softening region; (3) non-linear elastic region or re-stretching of the network; (4) lower plateau in which dissociation of some newly made connections occurs...
July 8, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28677887/inferior-lead-discordance-in-ventricular-arrhythmias-a-specific-marker-for-certain-arrhythmia-locations
#17
Andres Enriquez, Rajeev K Pathak, Pasquale Santangeli, Jackson Jeikai Liang, Mohammed Al Rawahi, Tatsuya Hayashi, Danielle Muser, David S Frankel, Gregory Supple, Robert Schaller, David Lin, Saman Nazarian, Erica Zado, Francis E Marchlinski, Fermin C Garcia
BACKGROUND: Most idiopathic ventricular arrhythmias (VAs) originate from the outflow tracts and are characterized by an inferior axis on the 12-lead ECG. A group of patients will exhibit inferior lead discordance (ILD), demonstrating a positive QRS in lead II with negative QRS in III or the opposite finding. METHODS AND RESULTS: We identified patients undergoing ablation of idiopathic premature ventricular contractions (PVCs) or ventricular tachycardia (VT) between 2013 and 2015...
July 5, 2017: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/28673260/gene-expression-variations-in-high-altitude-adaptation-a-case-study-of-the-asiatic-toad-bufo-gargarizans
#18
Weizhao Yang, Yin Qi, Bin Lu, Liang Qiao, Yayong Wu, Jinzhong Fu
BACKGROUND: Genome-wide investigation of molecular mechanisms for high-altitude adaptation has attracted great attention in the last few years. In order to understand the contribution of gene expression level variations to high-altitude adaptation in Asiatic toads (Bufo gargarizans), we implemented a reciprocal transplant experiment between low- and high-altitude sites and sequenced 12 transcriptomes from brain, heart, and liver tissues. RESULTS: A large number of genes with expression differences (DEGs) between high- and low-altitude individuals (193 fixed and 844 plastic) were identified, and the majority of them were tissue specific...
July 3, 2017: BMC Genetics
https://www.readbyqxmd.com/read/28671972/diaphragm-a-mnemonic-to-describe-the-work-of-breathing-in-patients-with-respiratory-failure
#19
Aiman Tulaimat, William E Trick
BACKGROUND: The assessment of the work of breathing in the definitions of respiratory failure is vague and variable. OBJECTIVE: Identify a parsimonious set of signs to describe the work of breathing in hypoxemic, acutely ill patients. METHODS: We examined consecutive medical ICU patients receiving oxygen with a mask, non-invasive ventilation, or T-piece. A physician inspected each patient for 10 seconds, rated the level of respiratory distress, and then examined the patient for vital signs and 17 other physical signs...
2017: PloS One
https://www.readbyqxmd.com/read/28639137/the-frank-starling-law-a-jigsaw-of-titin-proportions
#20
REVIEW
Vasco Sequeira, Jolanda van der Velden
The Frank-Starling Law dictates that the heart is able to match ejection to the dynamic changes occurring during cardiac filling, hence efficiently regulating isovolumetric contraction and shortening. In the last four decades, efforts have been made to identify a common fundamental basis for the Frank-Starling heart that can explain the direct relationship between muscle lengthening and its increased sensitization to Ca(2+). The term 'myofilament length-dependent activation' describes the length-dependent properties of the myofilaments, but what is(are) the underlying molecular mechanism(s) is a matter of ongoing debate...
June 2017: Biophysical Reviews
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