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https://www.readbyqxmd.com/read/28742609/the-efficacy-of-dynamic-contract-relax-stretching-on-delayed-onset-muscle-soreness-among-healthy-individuals-a-randomized-clinical-trial
#1
Yanfei Xie, Beibei Feng, Kedi Chen, Lars L Andersen, Phil Page, Yuling Wang
OBJECTIVE: To evaluate the efficacy of dynamic contract-relax stretching on delayed-onset muscle soreness (DOMS) in the calf muscle of healthy individuals. DESIGN: Randomized clinical trial. SETTING: Research laboratory. PARTICIPANTS: Three groups of 16 healthy participants (n = 48) were recruited by convenience sampling. INTERVENTIONS: Three sets of resisted bilateral heel-raising exercises until exhaustion were conducted to initiate DOMS...
July 21, 2017: Clinical Journal of Sport Medicine: Official Journal of the Canadian Academy of Sport Medicine
https://www.readbyqxmd.com/read/28725529/recent-progress-on-piezoelectric-and-triboelectric-energy-harvesters-in-biomedical-systems
#2
REVIEW
Qiang Zheng, Bojing Shi, Zhou Li, Zhong Lin Wang
Implantable medical devices (IMDs) have become indispensable medical tools for improving the quality of life and prolonging the patient's lifespan. The minimization and extension of lifetime are main challenges for the development of IMDs. Current innovative research on this topic is focused on internal charging using the energy generated by the physiological environment or natural body activity. To harvest biomechanical energy efficiently, piezoelectric and triboelectric energy harvesters with sophisticated structural and material design have been developed...
July 2017: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
https://www.readbyqxmd.com/read/28714118/body-wall-structure-in-the-starfish-asterias-rubens
#3
Liisa M Blowes, Michaela Egertová, Yankai Liu, Graham R Davis, Nick J Terrill, Himadri S Gupta, Maurice R Elphick
The body wall of starfish is composed of magnesium calcite ossicles connected by collagenous tissue and muscles and it exhibits remarkable variability in stiffness, which is attributed to the mechanical mutability of the collagenous component. Using the common European starfish Asterias rubens as an experimental animal, here we have employed a variety of techniques to gain new insights into the structure of the starfish body wall. The structure and organisation of muscular and collagenous components of the body wall were analysed using trichrome staining...
September 2017: Journal of Anatomy
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
#4
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/28670352/flow-and-transport-effect-caused-by-the-stalk-contraction-cycle-of-vorticella-convallaria
#5
Jiazhong Zhou, Sangjin Ryu, David Admiraal
Vorticella convallaria is a protozoan attached to a substrate by a stalk which can contract in less than 10 ms, translating the zooid toward the substrate with a maximum Reynolds number of ∼1. Following contraction, the stalk slowly relaxes, moving the zooid away from the substrate, which results in creeping flow. Although Vorticella has long been believed to contract to evade danger, it has been suggested that its stalk may contract to enhance food transport near the substrate. To elucidate how Vorticella utilizes its contraction-relaxation cycle, we investigated water flow caused by the cycle, using a computational fluid dynamics model validated with an experimental scale model and particle tracking velocimetry...
May 2017: Biomicrofluidics
https://www.readbyqxmd.com/read/28643702/surface-magnetism-of-l10-copt-alloy-first-principles-predictions
#6
Zhenyu Liu, Guofeng Wang
We used the first-principles density functional theory (DFT) to predict the magnetic properties of (1 0 0), (0 0 1), (1 0 1), (1 1 0), and (1 1 1) surfaces of L10 ordered CoPt alloy. Our results indicate that bulk-terminated CoPt surfaces exhibit magnetic moment higher than that of bulk CoPt crystal and surface magnetic anisotropy favoring in-plane magnetization. Moreover, our DFT calculations predict that Pt prefers to segregate to the outermost layer of all these five CoPt surfaces with energy gain in the range of 0...
September 6, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28624852/vasoconstrictor-responsiveness-in-contracting-human-muscle-influence-of-contraction-frequency-contractile-work-and-metabolic-rate
#7
Nicholas T Kruse, William E Hughes, Kenichi Ueda, Darren P Casey
PURPOSE: The aim of this study was to examine whether independent effects exist between contractile work and metabolic demand (VO2m) on vasoconstrictor responsiveness (i.e., functional sympatholysis) under different contraction durations matched for total contractile work in exercising human skeletal muscle. METHODS: Ten young men performed rhythmic forearm contractions at 10 and 15% of maximum voluntary contraction (MVC) which consisted of muscle contractions using the same duty cycle but altering the duration of the contraction-relaxation cycles of exercise and included: 1) fast frequency contractions at 10% MVC (FFC10%) using a contraction relaxation cycle at 1:2 s; 2) slow frequency contractions at 10% MVC (SFC10%) at 2:4 s; and 3) SFC at 15% MVC (SFC15%) at 2:4 s...
August 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28596242/smooth-muscle-function-and-myosin-polymerization
#8
Pasquale Chitano, Lu Wang, Gabrielle Y Y Tin, Mitsuo Ikebe, Peter D Paré, Chun Y Seow
Smooth muscle is able to function over a much broader length range than striated muscle. The ability to maintain contractility after a large length change is thought to be due to an adaptive process involving restructuring of the contractile apparatus to maximize overlap between the contractile filaments. The molecular mechanism for the length-adaptive behavior is largely unknown. In smooth muscle adapted to different lengths we quantified myosin monomers, basal and activation-induced myosin light chain (MLC) phosphorylation, shortening-velocity, power-output and active force...
June 8, 2017: Journal of Cell Science
https://www.readbyqxmd.com/read/28376365/bioacoustic-enabled-patterning-of-human-ipsc-derived-cardiomyocytes-into-3d-cardiac-tissue
#9
Vahid Serpooshan, Pu Chen, Haodi Wu, Soah Lee, Arun Sharma, Daniel A Hu, Sneha Venkatraman, Adarsh Venkataraman Ganesan, Osman Berk Usta, Martin Yarmush, Fan Yang, Joseph C Wu, Utkan Demirci, Sean M Wu
The creation of physiologically-relevant human cardiac tissue with defined cell structure and function is essential for a wide variety of therapeutic, diagnostic, and drug screening applications. Here we report a new scalable method using Faraday waves to enable rapid aggregation of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) into predefined 3D constructs. At packing densities that approximate native myocardium (10(8)-10(9) cells/ml), these hiPSC-CM-derived 3D tissues demonstrate significantly improved cell viability, metabolic activity, and intercellular connection when compared to constructs with random cell distribution...
July 2017: Biomaterials
https://www.readbyqxmd.com/read/28373957/comparative-study-the-expression-of-calcium-cycling-genes-in-bombay-duck-harpadon-nehereus-and-beltfish-trichiurus-lepturus-with-different-swimming-activities
#10
Hui Zhang, Gilbert Audira, Yuan Li, Weiwei Xian, Muhammed Muhsin Varikkodan, Chung-Der Hsiao
The contraction and relaxation events of the muscle is mediated by the coordination of many important calcium cycling proteins of ryanodine receptor (RYR), troponin C (TNNC), parvalbumin (PVALB), sarcoendoplasmic reticulum calcium transport ATPase (SERCA) and calsequestrin (CASQ). In higher vertebrates, the expression level of calcium cycling proteins are positively correlated to the muscle contraction/relaxation ability of the cell. In this study, we used RNAseq to explore the expression profile of calcium cycling genes between two marine fish of Bombay duck (Harpadon nehereus) and beltfish (Trichiurus lepturus) with poor and robust swimming activities, respectively...
June 2017: Genomics Data
https://www.readbyqxmd.com/read/28274093/canonical-transient-receptor-potential-channels-and-their-link-with-cardio-cerebro-vascular-diseases
#11
REVIEW
Xiong Xiao, Hui-Xia Liu, Kuo Shen, Wei Cao, Xiao-Qiang Li
The canonical transient receptor potential channels (TRPCs) constitute a series of nonselective cation channels with variable degrees of Ca²⁺ selectivity. TRPCs consist of seven mammalian members, TRPC1, TRPC2, TRPC3, TRPC4, TRPC5, TRPC6, and TRPC7, which are further divided into four subtypes, TRPC1, TRPC2, TRPC4/5, and TRPC3/6/7. These channels take charge of various essential cell functions such as contraction, relaxation, proliferation, and dysfunction. This review, organized into seven main sections, will provide an overview of current knowledge about the underlying pathogenesis of TRPCs in cardio/cerebrovascular diseases, including hypertension, pulmonary arterial hypertension, cardiac hypertrophy, atherosclerosis, arrhythmia, and cerebrovascular ischemia reperfusion injury...
March 10, 2017: Biomolecules & Therapeutics
https://www.readbyqxmd.com/read/28235365/titanium-dioxide-modulation-of-the-contractibility-of-visceral-smooth-muscles-in-vivo
#12
Olga V Tsymbalyuk, Anna M Naumenko, Oleksandr O Rohovtsov, Mykola A Skoryk, Ivan S Voiteshenko, Valeriy A Skryshevsky, Tamara L Davydovska
Electronic scanning microscopy was used in the work to obtain the image and to identify the sizes of titanium dioxide (TiO2) nanoparticles 21 ± 5 nm. The qualitative and quantitative elemental analysis of the preparations of the caecum, antrum, myometrium, kidneys, and lungs of the rats, burdened with titanium dioxide, was also performed. It was established using the tenzometric method in the isometric mode that the accumulation of titanium dioxide in smooth muscles of the caecum resulted in the considerable, compared to the control, increase in the frequency of their spontaneous contractions, the decrease in the duration of the contraction-relaxation cycle, and the decrease in the indices of muscle functioning efficiency (the index of contractions in Montevideo units (MU) and the index of contractions in Alexandria units (AU))...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28212795/nanojunctions-of-the-sarcoplasmic-reticulum-deliver-site-and-function-specific-calcium-signaling-in-vascular-smooth-muscles
#13
A M Evans
Vasoactive agents may induce myocyte contraction, dilation, and the switch from a contractile to a migratory-proliferative phenotype(s), which requires changes in gene expression. These processes are directed, in part, by Ca(2+) signals, but how different Ca(2+) signals are generated to select each function is enigmatic. We have previously proposed that the strategic positioning of Ca(2+) pumps and release channels at membrane-membrane junctions of the sarcoplasmic reticulum (SR) demarcates cytoplasmic nanodomains, within which site- and function-specific Ca(2+) signals arise...
2017: Advances in Pharmacology
https://www.readbyqxmd.com/read/28164457/isometric-thermogenesis-at-rest-and-during-movement-a-neglected-variable-in-energy-expenditure-and-obesity-predisposition
#14
REVIEW
A G Dulloo, J L Miles-Chan, J-P Montani, Y Schutz
Isometric thermogenesis as applied to human energy expenditure refers to heat production resulting from increased muscle tension. While most physical activities consist of both dynamic and static (isometric) muscle actions, the isometric component is very often essential for the optimal performance of dynamic work given its role in coordinating posture during standing, walking and most physical activities of everyday life. Over the past 75 years, there has been sporadic interest into the relevance of isometric work to thermoregulatory thermogenesis and to adaptive thermogenesis pertaining to body-weight regulation...
February 2017: Obesity Reviews: An Official Journal of the International Association for the Study of Obesity
https://www.readbyqxmd.com/read/28097712/force-generation-by-titin-folding
#15
Zsolt Mártonfalvi, Pasquale Bianco, Katalin Naftz, György G Ferenczy, Miklós Kellermayer
Titin is a giant protein that provides elasticity to muscle. As the sarcomere is stretched, titin extends hierarchically according to the mechanics of its segments. Whether titin's globular domains unfold during this process and how such unfolded domains might contribute to muscle contractility are strongly debated. To explore the force-dependent folding mechanisms, here we manipulated skeletal-muscle titin molecules with high-resolution optical tweezers. In force-clamp mode, after quenching the force (<10 pN), extension fluctuated without resolvable discrete events...
July 2017: Protein Science: a Publication of the Protein Society
https://www.readbyqxmd.com/read/28091624/paracrine-cross-talk-between-skeletal-muscle-and-macrophages-in-exercise-by-pgc-1%C3%AE-controlled-bnp
#16
Regula Furrer, Petra S Eisele, Alexander Schmidt, Markus Beer, Christoph Handschin
Activation of resident and infiltrating immune cells is a central event in training adaptation and other contexts of skeletal muscle repair and regeneration. A precise orchestration of inflammatory events in muscle fibers and immune cells is required after recurrent contraction-relaxation cycles. However, the mechanistic aspects of this important regulation remain largely unknown. We now demonstrate that besides a dominant role in controlling cellular metabolism, the peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α) also has a profound effect on cytokine expression in muscle tissue...
January 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28008669/r-type-ca-2-channels-couple-to-inhibitory-neurotransmission-to-the-longitudinal-muscle-in-the-guinea-pig-ileum
#17
Eileen S Rodriguez-Tapia, Vinogran Naidoo, Matthew DeVries, Alberto Perez-Medina, James J Galligan
What is the central question of this study? Subtypes of enteric neurons are coded by the neurotransmitters they synthesize, but it is not known whether enteric neuron subtypes might also be coded by other proteins, including calcium channel subtypes controlling neurotransmitter release. What is the main finding and its importance? Our data indicate that guinea-pig ileum myenteric neuron subtypes may be coded by calcium channel subtypes. We found that R-type calcium channels are expressed by inhibitory but not excitatory longitudinal muscle motoneurons...
March 1, 2017: Experimental Physiology
https://www.readbyqxmd.com/read/27881388/hyperglycemia-induces-defective-ca2-homeostasis-in-cardiomyocytes
#18
Andrea Sorrentino, Giulia Borghetti, Yu Zhou, Antonio Cannata, Marianna Meo, Sergio Signore, Piero Anversa, Annarosa Leri, Polina Goichberg, Khaled Qanud, Jason T Jacobson, Thomas H Hintze, Marcello Rota
Diabetes and other metabolic conditions characterized by elevated blood glucose constitute important risk factors for cardiovascular disease. Hyperglycemia targets myocardial cells rendering ineffective mechanical properties of the heart, but cellular alterations dictating the progressive deterioration of cardiac function with metabolic disorders remain to be clarified. In the current study, we examined the effects of hyperglycemia on cardiac function and myocyte physiology by employing mice with high blood glucose induced by administration of streptozotocin, a compound toxic to insulin-producing β-cells...
January 1, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27822383/neuronal-nitric-oxide-synthase-in-hypertension-an-update
#19
REVIEW
Yin Hua Zhang
Hypertension is a prevalent condition worldwide and is the key risk factor for fatal cardiovascular complications, such as stroke, sudden cardiac death and heart failure. Reduced bioavailability of nitric oxide (NO) in the endothelium is an important precursor for impaired vasodilation and hypertension. In the heart, NO deficiency deteriorates the adverse consequences of pressure-overload and causes cardiac hypertrophy, fibrosis and myocardial infarction which lead to fatal heart failure and sudden cardiac death...
2016: Clinical Hypertension
https://www.readbyqxmd.com/read/27796576/cardiac-inotropy-lusitropy-and-ca-2-handling-with-major-metabolic-substrates-in-rat-heart
#20
Zai Hao Zhao, Jae Boum Youm, Yue Wang, Jeong Hoon Lee, Jae Hwi Sung, Joon-Chul Kim, Sun Hee Woo, Chae Hun Leem, Sung Joon Kim, Lan Cui, Yin Hua Zhang
Fatty acid (FA)-dependent oxidation is the predominant process for energy supply in normal heart. Impaired FA metabolism and metabolic insufficiency underlie the failing of the myocardium. So far, FA metabolism in normal cardiac physiology and heart failure remains undetermined. Here, we evaluate the mechanisms of FA and major metabolic substrates (termed NF) on the contraction, relaxation, and Ca(2+) handling in rat left ventricular (LV) myocytes. Our results showed that NF significantly increased myocyte contraction and facilitated relaxation...
November 2016: Pflügers Archiv: European Journal of Physiology
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