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Cardiac mechanics

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https://www.readbyqxmd.com/read/27926871/in%C3%A2-vivo-visualization-of-cardiomyocyte-apicobasal-polarity-reveals-epithelial-to-mesenchymal-like-transition-during-cardiac-trabeculation
#1
Vanesa Jiménez-Amilburu, S Javad Rasouli, David W Staudt, Hiroyuki Nakajima, Ayano Chiba, Naoki Mochizuki, Didier Y R Stainier
Despite great strides in understanding cardiac trabeculation, many mechanistic aspects remain unclear. To elucidate how cardiomyocyte shape changes are regulated during this process, we engineered transgenes to label their apical and basolateral membranes. Using these tools, we observed that compact-layer cardiomyocytes are clearly polarized while delaminating cardiomyocytes have lost their polarity. The apical transgene also enabled the imaging of cardiomyocyte apical constriction in real time. Furthermore, we found that Neuregulin signaling and blood flow/cardiac contractility are required for cardiomyocyte apical constriction and depolarization...
December 6, 2016: Cell Reports
https://www.readbyqxmd.com/read/27926853/a-dynamical-threshold-for-cardiac-delayed-afterdepolarization-mediated-triggered-activity
#2
Michael B Liu, Christopher Y Ko, Zhen Song, Alan Garfinkel, James N Weiss, Zhilin Qu
Ventricular myocytes are excitable cells whose voltage threshold for action potential (AP) excitation is ∼-60 mV at which INa is activated to give rise to a fast upstroke. Therefore, for a short stimulus pulse to elicit an AP, a stronger stimulus is needed if the resting potential lies further away from the INa threshold, such as in hypokalemia. However, for an AP elicited by a long duration stimulus or a diastolic spontaneous calcium release, we observed that the stimulus needed was lower in hypokalemia than in normokalemia in both computer simulations and experiments of rabbit ventricular myocytes...
December 6, 2016: Biophysical Journal
https://www.readbyqxmd.com/read/27925233/quantification-and-analysis-of-leaflet-flutter-on-biological-prosthetic-cardiac-valves
#3
Artur H de F Avelar, Jean A Canestri, Camila Bim, Maíra G M Silva, Rudolf Huebner, Marcos Pinotti
The use of porcine or bovine pericardium biological cardiac valves has as its main disadvantage a relatively short lifespan, with failures due to calcification and fatigue. Increasing these valves' durability constitutes a great challenge. An understudied phenomenon is the effect of flutter, an oscillation of the leaflets that can cause regurgitation and accelerate calcification and fatigue. As a starting point to study how to reduce or prevent these oscillations, a method was developed to quantify the flutter frequencies occurring at the point of the valve's full opening...
December 7, 2016: Artificial Organs
https://www.readbyqxmd.com/read/27924974/mir-155-regulates-high-glucose-induced-cardiac-fibrosis-via-the-tgf-%C3%AE-signaling-pathway
#4
Dong Zhang, Yongchun Cui, Bin Li, Xiaokang Luo, Bo Li, Yue Tang
Cardiac fibrosis, as a pathological process, plays an important role in various cardiac diseases. microRNA-155 (miR-155) is one of the most important miRNAs, and previous studies have shown that it is a regulatory factor in various fibrotic diseases. However, the mechanism by which miR-155 affects myocardial fibrosis remains unclear. In this study, we aim to establish the biological function of miR-155 in myocardial fibrosis induced by diabetes in mice. We used normal C57BL/6 wild type (WT) and miR-155 knockout (KO) mice to establish the diabetic model by intraperitoneal injection of streptozotocin, and we utilized echocardiography to evaluate the cardiac function at 30 and 60 days post-modeling...
December 7, 2016: Molecular BioSystems
https://www.readbyqxmd.com/read/27924221/targeting-mll1-h3k4-methyltransferase-activity-to-guide-cardiac-lineage-specific-reprogramming-of-fibroblasts
#5
Liu Liu, Ienglam Lei, Hacer Karatas, Yangbing Li, Li Wang, Leonid Gnatovskiy, Yali Dou, Shaomeng Wang, Li Qian, Zhong Wang
Generation of induced cardiomyocytes (iCMs) directly from fibroblasts offers a great opportunity for cardiac disease modeling and cardiac regeneration. A major challenge of iCM generation is the low conversion rate. To address this issue, we attempted to identify small molecules that could potentiate the reprogramming ability towards cardiac fate by removing inhibitory roadblocks. Using mouse embryonic fibroblasts as the starting cell source, we first screened 47 cardiac development related epigenetic and transcription factors, and identified an unexpected role of H3K4 methyltransferase Mll1 and related factor Men1 in inhibiting iCM reprogramming...
2016: Cell Discovery
https://www.readbyqxmd.com/read/27924170/use-of-a-respiratory-volume-monitor-to-assess-respiratory-competence-in-cardiac-surgery-patients-after-extubation
#6
Stephan Ianchulev, Diane Ladd, C Marshall MacNabb, Lizeng Qin, Nathan Marengi, Jenny Freeman
BACKGROUND: Patients who have undergone cardiac surgery are generally mechanically ventilated postoperatively. Early postoperative extubation is currently recommended in anesthesia guidelines. No current technology can accurately, non-invasively, measure respiratory competence after extubation. Pulse oximetry has been helpful, but this is a late indicator of respiratory compromise. A novel, non-invasive, respiratory volume monitor (RVM) has been shown to deliver accurate continuous, real-time minute ventilation (MV), tidal volume (TV) and respiratory rate (RR) measurements and provide an objective measure of respiratory competence...
January 2017: Journal of Clinical Medicine Research
https://www.readbyqxmd.com/read/27924060/a-novel-mechanism-underlies-atrazine-toxicity-in-quails-coturnix-coturnix-coturnix-triggering-ionic-disorder-via-disruption-of-atpases
#7
Jia Lin, Hui-Xin Li, Lei Qin, Zheng-Hai Du, Jun Xia, Jin-Long Li
The widely used atrazine has been reported to exhibit extensive ecological hazards. Due to the biological accumulation, atrazine elicits widespread toxic effects on different organisms. However, true proof for the mechanism of atrazine-induced toxicity is lacking. To determine the potential mechanism by which atrazine exerted toxic effects, quails were treated with atrazine (0, 50, 250 and 500 mg/kg) by gavage administration for 45 days. Atrazine significantly increased the histological alterations and serum creatine kinase, lactate dehydrogenase and choline esterase levels...
December 4, 2016: Oncotarget
https://www.readbyqxmd.com/read/27923445/daily-exercise-prevents-diastolic-dysfunction-and-oxidative-stress-in-a-female-mouse-model-of-western-diet-induced-obesity-by-maintaining-cardiac-heme-oxygenase-1-levels
#8
Brian Bostick, Annayya R Aroor, Javad Habibi, William Durante, Lixin Ma, Vincent G DeMarco, Mona Garro, Melvin R Hayden, Frank W Booth, James R Sowers
OBJECTIVE: Obesity is a global epidemic with profound cardiovascular disease (CVD) complications. Obese women are particularly vulnerable to CVD, suffering higher rates of CVD compared to non-obese females. Diastolic dysfunction is the earliest manifestation of CVD in obese women but remains poorly understood with no evidence-based therapies. We have shown early diastolic dysfunction in obesity is associated with oxidative stress and myocardial fibrosis. Recent evidence suggests exercise may increase levels of the antioxidant heme oxygenase-1 (HO-1)...
January 2017: Metabolism: Clinical and Experimental
https://www.readbyqxmd.com/read/27922691/microarray-expression-profiles-of-genes-in-lung-tissues-of-rats-subjected-to-focal-cerebral-ischemia-induced-lung-injury-following-bone-marrow-derived-mesenchymal-stem-cell-transplantation
#9
Yue Hu, Liu-Lin Xiong, Piao Zhang, Ting-Hua Wang
Ischemia-induced stroke is the most common disease of the nervous system and is associated with a high mortality rate worldwide. Cerebral ischemia may lead to remote organ dysfunction, particular in the lungs, resulting in lung injury. Nowadays, bone marrow-derived mesenchymal stem cells (BMSCs) are widely studied in clinical trials as they may provide an effective solution to the treatment of neurological and cardiac diseases; however, the underlying molecular mechanisms remain unknown. In this study, a model of permanent focal cerebral ischemia-induced lung injury was successfully established and confirmed by neurological evaluation and lung injury scores...
December 6, 2016: International Journal of Molecular Medicine
https://www.readbyqxmd.com/read/27922664/expression-of-bcl-2-and-micrornas-in-cardiac-tissues-of-patients-with-dilated-cardiomyopathy
#10
Yong Wang, Min Li, Li Xu, Ju Liu, Dong Wang, Quan Li, Lili Wang, Peijie Li, Shanliang Chen, Tianqi Liu
Dilated cardiomyopathy (DCM) is associated with sudden cardiac death and heart failure, resulting in a significant medical burden. The mechanisms underlying the pathogenesis of DCM remain elusive. In the present study, human cardiac tissues from patients with DCM and healthy donors were collected and their pathology was examined. The expression levels of apoptosis regulator Bcl-2 and fibrosis-associated microRNAs were also evaluated. Extensive myocardial fibrosis and apoptosis in DCM cardiac tissues was observed...
December 2, 2016: Molecular Medicine Reports
https://www.readbyqxmd.com/read/27922334/ionizing-radiation-impairs-endogenous-regeneration-of-infarcted-heart-an-in-vivo-18-f-fdg-pet-ct-and-99m-tc-tetrofosmin-spect-ct-study-in-mice
#11
Lan Luo, Kodai Nishi, Yoshishige Urata, Chen Yan, Al Shaimaa Hasan, Shinji Goto, Takashi Kudo, Zhao-Lan Li, Tao-Sheng Li
Epidemiological studies have suggested that ionizing radiation increases cardiovascular disease risk, but the relevant mechanism is poorly understood. We recently demonstrated that adult mice exposed to whole-body irradiation with 3 Gy gamma rays significantly decreases the number and quality of cardiac stem cells. To further determine if radiation impairs myocardial regenerative potency, a myocardial infarction model was established in adult C57BL/6 mice by ligating the left anterior descending artery approximately 6 h after sham- or whole-body gamma irradiation (0 or 3 Gy)...
December 6, 2016: Radiation Research
https://www.readbyqxmd.com/read/27922120/regulation-of-human-cardiac-potassium-channels-by-full-length-kcne3-and-kcne4
#12
Geoffrey W Abbott
Voltage-gated potassium (Kv) channels comprise pore-forming α subunits and a multiplicity of regulatory proteins, including the cardiac-expressed and cardiac arrhythmia-linked transmembrane KCNE subunits. After recently uncovering novel, N-terminally extended (L) KCNE3 and KCNE4 isoforms and detecting their transcripts in human atrium, reported here are their functional effects on human cardiac Kv channel α subunits expressed in Xenopus laevis oocytes. As previously reported for short isoforms KCNE3S and KCNE4S, KCNE3L inhibited hERG; KCNE4L inhibited Kv1...
December 6, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27921112/-gastroenterological-diseases-as-triggers-of-chest-pain
#13
J Labenz, C Labenz
BACKGROUND: Non-cardiac chest pain is very common and gastroenterological diseases are one of the most important causes. The frequency distribution of the underlying causes depends on the sector of the healthcare system in which it is ascertained. In individual cases it must always be taken into consideration that detection of coronary heart disease, for example, does not exclude another origin of chest pain. OBJECTIVE: This article provides a systematic review of gastroenterological diseases that can cause chest pain...
December 5, 2016: Der Internist
https://www.readbyqxmd.com/read/27920725/controlled-reperfusion-strategies-improve-cardiac-hemodynamic-recovery-after-warm-global-ischemia-in-an-isolated-working-rat-heart-model-of-donation-after-circulatory-death-dcd
#14
Emilie Farine, Petra Niederberger, Rahel K Wyss, Natalia Méndez-Carmona, Brigitta Gahl, Georg M Fiedler, Thierry P Carrel, Hendrik T Tevaearai Stahel, Sarah L Longnus
Aims: Donation after circulatory death (DCD) could improve cardiac graft availability, which is currently insufficient to meet transplant demand. However, DCD organs undergo an inevitable period of warm ischemia and most cardioprotective approaches can only be applied at reperfusion (procurement) for ethical reasons. We investigated whether modifying physical conditions at reperfusion, using four different strategies, effectively improves hemodynamic recovery after warm ischemia. Methods and Results: Isolated hearts of male Wistar rats were perfused in working-mode for 20 min, subjected to 27 min global ischemia (37°C), and 60 min reperfusion (n = 43)...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27920655/deep-vein-thrombosis-as-initial-manifestation-of-whipple-disease
#15
Mônica Souza de Miranda Henriques, Alexandre Rolim da Paz, Ana Beatriz Person Gaertner, Cibelle Ingrid Stephen Melo, Priscyanne Lins Filgueiras, Rafaella Alencar Jerome
INTRODUCTION: Wipple disease (WD) is a rare chronic disease caused by the bacillus Tropheryma whipplei. Constitutive, rheumatologic, gastrointestinal, cardiac, cerebral, lymphatic, cutaneous, and ophthalmological signs are possible systemic symptoms. However, thrombotic manifestations are rarely described as "stroke-like syndrome" or arterial thrombosis. Diagnosis is based on clinical manifestations and pathological examination. Laboratory findings may include anemia, leukocytosis, and thrombocytosis...
September 2016: Case Reports in Gastroenterology
https://www.readbyqxmd.com/read/27920591/left-atrial-myxomectomy-with-intraoperative-severe-mitral-regurgitation-and-complicated-postoperative-course-case-report
#16
Nareg Minaskeian, Patrick P Hu
Primary cardiac tumors are a rare occurrence with myxomas accounting for about half of the benign tumors. Once diagnosed, surgical resection is the standard of care. Our case describes a female in her 50s who underwent a myxoma resection under cardiopulmonary bypass via biatrial approach. Intraoperatively, the thin septal crux between the wall of the aorta and mitral valve was damaged during resection, requiring stem cell tissue matrix for repair. The patient also developed severe mitral regurgitation suggesting infarct to the left coronary system during resection, subsequently receiving a mechanical mitral valve and a saphenous vein bypass graft...
2016: Clinical Medicine Insights. Case Reports
https://www.readbyqxmd.com/read/27920122/microrna-33-controls-adaptive-fibrotic-response-in-the-remodeling-heart-by-preserving-lipid-raft-cholesterol
#17
Masataka Nishiga, Takahiro Horie, Yasuhide Kuwabara, Kazuya Nagao, Osamu Baba, Tetsushi Nakao, Tomohiro Nishino, Daihiko Hakuno, Yasuhiro Nakashima, Hitoo Nishi, Fumiko Nakazeki, Yuya Ide, Satoshi Koyama, Masahiro Kimura, Ritsuko Hanada, Tomoyuki Nakamura, Tsukasa Inada, Koji Hasegawa, Simon J Conway, Toru Kita, Takeshi Kimura, Koh Ono
RATIONALE: Heart failure (HF) and atherosclerosis share the underlying mechanisms of chronic inflammation followed by fibrosis. A highly conserved microRNA (miR), miR-33 is considered as a potential therapeutic target for atherosclerosis because it regulates lipid metabolism and inflammation. However, the role of miR-33 in HF remains to be elucidated. OBJECTIVE: To clarify the role of miR-33 involved in HF. METHODS AND RESULTS: We first investigated the expression levels of miR-33a/b in human cardiac tissue samples with dilated cardiomyopathy...
December 5, 2016: Circulation Research
https://www.readbyqxmd.com/read/27919338/effects-of-ionizing-radiation-on-the-heart
#18
Marjan Boerma, Vijayalakshmi Sridharan, Xiao-Wen Mao, Gregory A Nelson, Amrita K Cheema, Igor Koturbash, Sharda P Singh, Alan J Tackett, Martin Hauer-Jensen
This article provides an overview of studies addressing effects of ionizing radiation on the heart. Clinical studies have identified early and late manifestations of radiation-induced heart disease, a side effect of radiation therapy to tumors in the chest when all or part of the heart is situated in the radiation field. Studies in preclinical animal models have contributed to our understanding of the mechanisms by which radiation may injure the heart. More recent observations in human subjects suggest that ionizing radiation may have cardiovascular effects at lower doses than was previously thought...
October 2016: Mutation Research
https://www.readbyqxmd.com/read/27918847/left-ventricular-compressions-improve-hemodynamics-in-a-swine-model-of-out-of-hospital-cardiac-arrest
#19
Kenton L Anderson, Maria G Castaneda, Susan M Boudreau, Danny J Sharon, Vikhyat S Bebarta
INTRODUCTION: We hypothesized that chest compressions located directly over the left ventricle (LV) would improve hemodynamics, including coronary perfusion pressure (CPP), and return of spontaneous circulation (ROSC) in a swine model of cardiac arrest. METHODS: Transthoracic echocardiography (echo) was used to mark the location of the aortic root and the center of the left ventricle on animals (n = 26) which were randomized to receive chest compressions in one of the two locations...
December 5, 2016: Prehospital Emergency Care
https://www.readbyqxmd.com/read/27917819/pulsatile-flow-conditioning-of-three-dimensional-bioengineered-cardiac-ventricle
#20
Nikita M Patel, Ravi K Birla
Current physical stimuli mechanical stretch bioreactor studies focus on conditioning planar and/or tubular engineered cardiac constructs. The current 3D bioreactor models in cardiac tissue engineering use differential pressure loading for structural support as opposed to conditioning. The development of the pulsatile flow conditioned ventricle (PFCV) provides a 3D mechanical stretch conditioning method to generate pump function in the engineered cardiac left ventricle. The study utilizes a chitosan bioengineered open ventricle scaffold, to produce the in vitro PFCV model...
December 5, 2016: Biofabrication
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