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Long Liang, Christopher Jones, Shaohua Chen, Bo Sun, Yang Jiao
Collagen networks play an important role in coordinating and regulating collective cellular dynamics via a number of signaling pathways. Here, we investigate the transmission of forces generated by contractile cells in 3D collagen-I networks. Specifically, the graph (bond-node) representations of collagen networks with collagen concentrations of 1, 2 and 4 mg ml(-1) are derived from confocal microscopy data and used to model the network microstructure. Cell contraction is modeled by applying correlated displacements at specific nodes of the network, representing the focal adhesion sites...
October 25, 2016: Physical Biology
Ibrahim J Domian, Hanry Yu, Nikhil Mittal
In this essay the authors argue that chamber pressure dominates the biomechanics of the contraction cycle of the heart, while tissue stiffness dominates the relaxation cycle. This appears to be an under-recognized challenge in cardiac tissue engineering. Optimal approaches will involve constructing chambers or modulating the stiffness of the scaffold/substrate in synchrony with the beating cycle.
October 24, 2016: Advanced Healthcare Materials
Takeshi Kinoshita, Masashi Tawa, Tomoaki Suzuki, Yoshinari Aimi, Tohru Asai, Tomio Okamura
OBJECTIVES: The present study was designed to evaluate the association between chronic kidney disease and the endothelial function of internal thoracic artery (ITA) grafts in patients undergoing coronary bypass surgery. An isometric tension study was performed in ITA strips obtained during surgery. Concentration-response curves for acetylcholine (ACh) and sodium nitroprusside were constructed in ITA strips partially precontracted with phenylephrine under the inhibition of cyclooxygenase...
September 23, 2016: Journal of Thoracic and Cardiovascular Surgery
Jeffrey J Widrick, Matthew Alexander, Benjamin Sanchez, Devin Gibbs, Genri Kawahara, Alan Beggs, Louis Kunkel
Sapje zebrafish lack the protein dystrophin and are the smallest vertebrate model of Duchenne muscular dystrophy (DMD). Their small size makes them ideal for large-scale drug discovery screens. However, the extent that sapje mimic the muscle dysfunction of higher vertebrate models of DMD is unclear. We used an optical birefringence assay to differentiate affected dystrophic sapje larvae from their unaffected siblings and then studied trunk muscle contractility at 4-7 days post fertilization. Preparation cross-sectional area (CSA) was similar for affected and unaffected larvae, yet tetanic forces of affected preparations were only 30-60% of normal...
October 7, 2016: Physiological Genomics
Luca Fusi, Valentina Percario, Elisabetta Brunello, Marco Caremani, Pasquale Bianco, Joseph D Powers, Massimo Reconditi, Vincenzo Lombardi, Gabriella Piazzesi
KEY POINTS: Myosin filament mechanosensing determines the efficiency of the contraction by adapting the number of switched ON motors to the load. Accordingly, the unloaded shortening velocity (V0 ) is already set at the end of the latency relaxation (LR), ∼10 ms after the start of stimulation, when the myosin filament is still in the OFF state. Here the number of actin-attached motors per half-myosin filament (n) during V0 shortening imposed either at the end of LR or at the plateau of the isometric contraction is estimated from the relation between half-sarcomere compliance and force during the force redevelopment after the shortening...
October 20, 2016: Journal of Physiology
Riccardo Bientinesi, Cesare Mancuso, Maria Martire, Pier Francesco Bassi, Emilio Sacco, Diego Currò
Voltage-gated type 7 K(+) (KV7 or KCNQ) channels regulate the contractility of various smooth muscles. With this study, we aimed to assess the role of KV7 channels in the regulation of human detrusor contractility, as well as the gene and protein expression of KV7 channels in this tissue. For these purposes, the isolated organ technique, RT-qPCR, and Western blot were used, respectively. XE-991, a selective KV7 channel blocker, concentration-dependently contracted the human detrusor; mean EC50 and Emax of XE-991-induced concentration-response curve were 14...
October 19, 2016: Naunyn-Schmiedeberg's Archives of Pharmacology
Josef Donnerer, Ingrid Liebmann
Allyl isothiocyanate (AITC, mustard oil, 50-200 µmol/l), depending on specific dosages, inhibited the cholinergic twitch response in the longitudinal muscle-myenteric plexus (LMMP) strip of the guinea-pig ileum. AITC also induced short-lasting contractile responses, and decreases of the basal tone of the LMMP strip at low concentrations and increases at high concentrations. Hexamethonium, a blocker of nicotinic ganglionic transmission, was able to prevent the AITC-evoked inhibitory effect, an effect that was also observed with the opioid antagonist naloxone...
October 19, 2016: Pharmacology
Francisco J Rios, Katie Y Hood, A Karvey, Karla B Neves, Panagiota Anyfanti, Ryszard Nosalski, Livia L Camargo Ll, Augusto C Montezano, Rhian M Touyz
OBJECTIVE: TRPM7 is cation channel with intrinsic kinase activity important for cellular Mg homeostasis. We recently showed that TRPM7-kinase plays a role in aldosterone-mediated vascular effects and inflammation. Here we explored the putative role of TRPM7-kinase in cardiac fibrosis and vascular function in aldosterone-induced hypertension in mice. DESIGN AND METHOD: Wild-type (WT) or heterozygote TRPM7-kinase domain (TRPM7+/-) mice were treated with infused aldosterone (600 μg/Kg/day) and NaCl 1% in drinking water (aldo/salt) for 4 weeks...
September 2016: Journal of Hypertension
Justin Parreno, Sneha Raju, Po-Han Wu, Rita A Kandel
Chondrocyte culture as a monolayer for cell number expansion results in dedifferentiation whereby expanded cells acquire contractile features and increased actin polymerization status. This study determined whether the actin polymerization based signaling pathway, myocardin-related transcription factor-a (MRTF-A) is involved in regulating this contractile phenotype. Serial passaging of chondrocytes in monolayer culture to passage 2 resulted in increased gene and protein expression of the contractile molecules alpha-smooth muscle actin, transgelin and vinculin compared to non-passaged, primary cells...
October 14, 2016: Matrix Biology: Journal of the International Society for Matrix Biology
Li-Jie Wang, Wei-Dong Liu, Liang Zhang, Ke-Tao Ma, Lei Zhao, Wen-Yan Shi, Wen-Wen Zhang, Ying-Zi Wang, Li Li, Jun-Qiang Si
Niflumic acid (NFA) is a novel gap junction (GJ) inhibitor. The aim of the present study was to investigate the effect of NFA on GJ communication and the expression of connexin (Cx) in vascular smooth muscle cells (VSMCs) of mesenteric arterioles of spontaneously hypertensive rats (SHR). Whole‑cell patch clamp recording demonstrated that NFA at 1x10‑4 M significantly inhibited the inward current and its effect was reversible. The time for charging and discharging of cell membrane capacitance (Cinput) reduced from 9...
September 26, 2016: Molecular Medicine Reports
Wangde Dai, Elissa Cheung, Rick J Alleman, Justin B Perry, Mitchell E Allen, David A Brown, Robert A Kloner
PURPOSE: Dysfunctional mitochondria are considered to be the major source of intracellular reactive oxygen species and play a central role in the pathophysiology of myocardial ischemia/reperfusion. This study sought to determine effects of mitochondria-targeted cytoprotective peptide SBT-20 on myocardial infarct size in two different models of ischemia/reperfusion. METHODS: For in vivo studies, anesthetized Sprague Dawley rats were subjected to 30 min of coronary artery occlusion followed by 3 h of reperfusion...
October 17, 2016: Cardiovascular Drugs and Therapy
M Hirschvogel, M Bassilious, L Jagschies, S M Wildhirt, M W Gee
A model for patient-specific cardiac mechanics simulation is introduced, incorporating a 3-dimensional finite element model of the ventricular part of the heart which is coupled to a reduced-order 0-dimensional closed-loop vascular system, heart valve and atrial chamber model.The ventricles are modeled by a nonlinear orthotropic passive material law. The electrical activation is mimicked by a prescribed parametrized active stress acting along a generic muscle fiber orientation. Our activation function is constructed such that the start of ventricular contraction and relaxation as well as the active stress curve's slope are parameterized...
October 15, 2016: International Journal for Numerical Methods in Biomedical Engineering
P Kalbe
The reform of occupational insurance medical treatment in 2011 also resulted in many changes for occupational insurance consultants in private practice. The transformation of the physicians participating in treatment status (H-Arzt) to accident insurance consultant status (D-Arzt) has resulted in a significant increase in numbers in outpatient fields, which in some cases leads to increased competition. The tentative flexibilization of the conditions for participation of a D‑Arzt is welcomed but must be broadened to safeguard the future...
October 14, 2016: Der Unfallchirurg
Eduardo Fernández-Martínez, Héctor Ponce-Monter, Luis E Soria-Jasso, Mario I Ortiz, José-Antonio Arias-Montaño, Guillermo Barragán-Ramírez, Cynthia Mayén-García
Uterine relaxation is crucial during preterm labor. Phosphodiesterase-4 (PDE-4) inhibitors have been proposed as tocolytics. Some thalidomide analogs are PDE-4 inhibitors. The aim of this study was to assess the uterus-relaxant properties of two thalidomide analogs, methyl 3-(4-nitrophthalimido)-3-(3,4-dimethoxyphenyl)-propanoate (4NO2PDPMe) and methyl 3-(4-aminophthalimido)-3-(3,4-dimethoxyphenyl)-propanoate (4APDPMe) and were compared to rolipram in functional studies of spontaneous phasic, K⁺-induced tonic, and Ca(2+)-induced contractions in isolated pregnant human myometrial tissues...
October 7, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Sofya Kulikova, Lucie Hertz-Pannier, Ghislaine Dehaene-Lambertz, Cyril Poupon, Jessica Dubois
The volume fraction of water related to myelin (fmy) is a promising MRI index for in vivo assessment of brain myelination, that can be derived from multi-component analysis of T1 and T2 relaxometry signals. However, existing quantification methods require rather long acquisition and/or post-processing times, making implementation difficult both in research studies on healthy unsedated children and in clinical examinations. The goal of this work was to propose a novel strategy for fmy quantification within acceptable acquisition and post-processing times...
2016: PloS One
Junqi Huang, Ting Gang Chew, Ying Gu, Saravanan Palani, Anton Kamnev, Douglas S Martin, Nicholas J Carter, Robert Anthony Cross, Snezhana Oliferenko, Mohan K Balasubramanian
Many eukaryotes assemble a ring-shaped actomyosin network that contracts to drive cytokinesis. Unlike actomyosin in sarcomeres, which cycles through contraction and relaxation, the cytokinetic ring disassembles during contraction through an unknown mechanism. Here we find in Schizosaccharomyces japonicus and Schizosaccharomyces pombe that, during actomyosin ring contraction, actin filaments associated with actomyosin rings are expelled as micron-scale bundles containing multiple actomyosin ring proteins. Using functional isolated actomyosin rings we show that expulsion of actin bundles does not require continuous presence of cytoplasm...
October 13, 2016: ELife
Marcin Kunecki, Wojciech Płazak, Tomasz Roleder, Jolanta Biernat, Tomasz Oleksy, Piotr Podolec, Krzysztof Stanisław Gołba
BACKGROUND: Ischemic preconditioning (IPC) and postconditioning (POC) are the novel strategies of attaining cardioprotection against ischemia/reperfusion (I/R) injury. Previous studies suggested the role of opioid pathway, however the class of opioid receptors responsible for this effect in humans remains unknown. The aim of the study was to assess the influence of opioids on simulated I/R injury outcomes in the human myocardium. METHODS: Trabeculae of the human right atrium were electrically driven in organ bath and subjected to simulated I/R injury...
October 13, 2016: Cardiology Journal
Kathirvel Gopalakrishnan, Amar S More, Gary D Hankins, Tatiana N Nanovskaya, Sathish Kumar
Approximately 20% of pregnant women smoke despite intentions to quit. Smoking cessation drugs, such as nicotine replacement therapy (NRT) and bupropion, are recommended treatments. Adverse cardiovascular outcomes in offspring have raised concerns about NRT's safety during pregnancy. However, the effect of bupropion is unknown. Using a rat model, we determined whether NRT and bupropion interventions during pregnancy are safer than continued smoking on offspring's cardiovascular function. Male offspring of controls and dams exposed to cigarette smoke (1...
October 12, 2016: Reproductive Sciences
Daniel A Hernandez, Christina M Bennett, Lyubov Dunina-Barkovskaya, Tatjana Wedig, Yassemi Capetanaki, Harald Herrmann, Gloria M Conover
In the hearts of patients bearing nebulette mutations, a severe general disorganization in cardiomyocytes of the extrasarcomeric desmin intermediate filament system is frequently observed. However, the molecular and functional relationship between the desmin cytoskeleton and nebulette-containing sarcomeres is still unclear. Here we report a high-affinity in vitro interaction between nebulette and desmin filaments. A major interaction site has been mapped to the desmin α-helical rod domain indicating that the filament core is directly involved in the binding of nebulette...
October 12, 2016: Molecular Biology of the Cell
Mustapha Bouhrara, Richard G Spencer
A number of central nervous system (CNS) diseases exhibit changes in myelin content and magnetic resonance longitudinal, T1, and transverse, T2, relaxation times, which therefore represent important biomarkers of CNS pathology. Among the methods applied for measurement of myelin water fraction (MWF) and relaxation times, the multicomponent driven equilibrium single pulse observation of T1 and T2 (mcDESPOT) approach is of particular interest. mcDESPOT permits whole brain mapping of multicomponent T1 and T2, with data acquisition accomplished within a clinically realistic acquisition time...
October 8, 2016: NeuroImage
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