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https://www.readbyqxmd.com/read/28334543/-functional-impact-of-herg-from-physiological-role-to-target-of-anticancer-therapy
#1
Júlia Šatková, Markéta Bébarová
The human ether-à-go-go related gene (hERG; officially designated as KCNH2) encodes the structure of protein forming α-subunit of voltage-gated ion channel which conducts the rapid component of delayed rectifier K+ current (IKr). This current plays an important role namely in the cardiac repolarization. Mutations in hERG result in inherited arrhythmogenic syndromes characterized by a lenghtening or shortening of QT interval on the electrocardiogram and by an increased occurrence of life-threatening arrhythmias...
2017: Vnitr̆ní Lékar̆ství
https://www.readbyqxmd.com/read/28334024/opposite-effects-of-5-ht-akh-and-octopamine-on-the-crop-contractions-in-adult-drosophila-melanogaster-evidence-of-a-double-brain-gut-serotonergic-circuitry
#2
Paolo Solari, Nicholas Rivelli, Francescaelena De Rose, Lorenzo Picciau, Ludovico Murru, John G Stoffolano, Anna Liscia
This study showed that in adult Drosophila melanogaster, the type of sugar-either present within the crop lumen or in the bathing solution of the crop-had no effect on crop muscle contraction. What is important, however, is the volume within the crop lumen. Electrophysiological recordings demonstrated that exogenous applications of serotonin on crop muscles increases both the amplitude and the frequency of crop contraction rate, while adipokinetic hormone mainly enhances the crop contraction frequency. Conversely, octopamine virtually silenced the overall crop activity...
2017: PloS One
https://www.readbyqxmd.com/read/28333386/myofilaments-movers-and-rulers-of-the-sarcomere
#3
Brian Leei Lin, Taejeong Song, Sakthivel Sadayappan
Striated cardiac and skeletal muscles play very different roles in the body, but they are similar at the molecular level. In particular, contraction, regardless of the type of muscle, is a precise and complex process involving the integral protein myofilaments and their associated regulatory components. The smallest functional unit of muscle contraction is the sarcomere. Within the sarcomere can be found a sophisticated ensemble of proteins associated with the thick filaments (myosin, myosin binding protein-C, titin, and obscurin) and thin myofilaments (actin, troponin, tropomyosin, nebulin, and nebulette)...
March 16, 2017: Comprehensive Physiology
https://www.readbyqxmd.com/read/28333173/functional-and-volumetric-analysis-of-the-pectoralis-major-muscle-after-submuscular-breast-augmentation
#4
Ana Claudia Roxo, Fabio Xerfan Nahas, Nadia Cristina Pinheiro Rodrigues, José Inácio Salles, Victor Rodrigues Amaral Cossich, Claudio Cardoso de Castro, Jose Horacio Aboudib, Ruy Garcia Marques
Background: Dual plane breast augmentation is a technical variation of the submuscular plane described as a technique that reduces contour deformities due to contraction of the pectoralis major muscle and lower risk of double-bubble deformity associated with breast ptosis. Despite improvement in the aesthetic aspect, there is still no consensus whether this technique affects the function of the pectoralis major muscle. Objectives: The aim of this study was to correlate functional with volumetric changes associated with dissection of the muscle origin in submuscular breast augmentation...
January 20, 2017: Aesthetic Surgery Journal
https://www.readbyqxmd.com/read/28332745/5-ht4-receptors-facilitate-cholinergic-neurotransmission-throughout-the-murine-gastrointestinal-tract
#5
V Pauwelyn, R A Lefebvre
BACKGROUND: In the gastrointestinal tract of several species, facilitating 5-HT4 receptors were proposed on myenteric cholinergic neurons innervating smooth muscle by in vitro study of the effect of the selective 5-HT4 receptor agonist prucalopride on submaximal cholinergic contractions. This was not yet established in the murine gastrointestinal tract. METHODS: In circular smooth muscle strips from murine fundus, jejunum and colon, contractions were induced by electrical field stimulation in the presence of guanethidine, L-NAME and for colon also MRS 2500...
March 23, 2017: Neurogastroenterology and Motility: the Official Journal of the European Gastrointestinal Motility Society
https://www.readbyqxmd.com/read/28332714/phosphate-increase-during-fatigue-affects-crossbridge-kinetics-in-intact-mouse-muscle-at-physiological-temperature
#6
M Nocella, G Cecchi, B Colombini
Actomyosin ATP hydrolysis during muscle contraction releases inorganic phosphate, increasing [Pi ] in the myoplasm. Experiments in skinned fibres at low temperature (10-12°C) have shown that [Pi ] increase depresses isometric force and alters the kinetics of actomyosin interaction. However, Pi effects decrease with temperature and this raises the question of Pi role under physiological conditions. The present experiments were made to investigate this point. Intact fibre bundles isolated from the flexor digitorum brevis of C57BL/6 mice were stimulated with a series of tetanic contractions at 1...
March 23, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28332633/structural-insights-into-the-nucleotide-base-specificity-of-p2x-receptors
#7
Go Kasuya, Yuichiro Fujiwara, Hisao Tsukamoto, Satoshi Morinaga, Satoshi Ryu, Kazushige Touhara, Ryuichiro Ishitani, Yuji Furutani, Motoyuki Hattori, Osamu Nureki
P2X receptors are trimeric ATP-gated cation channels involved in diverse physiological processes, ranging from muscle contraction to nociception. Despite the recent structure determination of the ATP-bound P2X receptors, the molecular mechanism of the nucleotide base specificity has remained elusive. Here, we present the crystal structure of zebrafish P2X4 in complex with a weak affinity agonist, CTP, together with structure-based electrophysiological and spectroscopic analyses. The CTP-bound structure revealed a hydrogen bond, between the cytosine base and the side chain of the basic residue in the agonist binding site, which mediates the weak but significant affinity for CTP...
March 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28332149/biomechanical-cadaveric-comparison-of-patellar-ligament-suture-protected-by-a-steel-cable-versus-a-synthetic-cable
#8
P Bouget, C Breque, J S Beranger, J P Faure, F Khiami, T Vendeuvre
BACKGROUND: Purpose and hypothesis: Patellar ligament rupture is a rare disabling pathology requiring a surgical ligament suture protected by a frame. The gold standard is the steel cable, but its rigidity and the necessity of a surgical re-intervention for its removal render it unsatisfactory. The objective of this paper is to quantify the mechanical protection provided by the terylene® in comparison with steel. METHODS: Twenty-four knees of 12 fresh frozen cadaveric subjects were divided into 2 homogeneous groups (terylene and steel) of 12 knees (mean age = 69...
December 2017: Journal of Experimental Orthopaedics
https://www.readbyqxmd.com/read/28332107/mechanisms-driving-gender-differences-in-asthma
#9
REVIEW
Hubaida Fuseini, Dawn C Newcomb
PURPOSE OF REVIEW: Many phenotypes of asthma exist, ranging from mild asthma with onset during childhood to severe asthma with later onset, making asthma a broad disease with different pathologies. A gender disparity exists in asthma prevalence. As adults, women have an increased asthma prevalence compared to men. Further, women are more likely to have severe asthma and a later onset of asthma compared to men. Here, we review clinical and animal studies that have defined the role of sex hormones in airway inflammation, smooth muscle contraction, mucus production, and airway mechanics associated with asthma pathogenesis...
March 2017: Current Allergy and Asthma Reports
https://www.readbyqxmd.com/read/28331221/relationship-between-joint-torque-and-muscle-fascicle-shortening-at-various-joint-angles-and-intensities-in-the-plantar-flexors
#10
Atsuki Fukutani, Jun Misaki, Tadao Isaka
Because it is difficult to measure tendon length changes directly in humans, tendon length changes during dynamic movement have been evaluated indirectly from changes in muscle fascicle length and joint angle. The purpose of this study was to examine the validity of the indirect method. Twitch contractions of the ankle plantar flexors were evoked isometrically in eight subjects. Twitch contractions evoked by singlet, doublet, and triplet stimulations were conducted at dorsiflexion 20° (DF20), plantar flexion 0° (PF0), and plantar flexion 20° (PF20)...
March 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28331075/myosin-activity-drives-actomyosin-bundle-formation-and-organization-in-contractile-cells-of-the-c-elegans-spermatheca
#11
Alison C E Wirshing, Erin J Cram
Stress fibers, contractile actomyosin bundles, are important for cellular force production and adaptation to physical stress and have been well-studied within the context of cell migration. However, less is known about actomyosin bundle formation and organization in vivo and in specialized contractile cells, such as smooth muscle and myoepithelial cells. The Caenorhabditis elegans spermatheca is a bag-like organ of 24 myoepithelial cells that houses the sperm and is the site of fertilization. During ovulation, spermathecal cells are stretched by oocyte entry and then coordinately contract to expel the fertilized embryo into the uterus...
March 22, 2017: Molecular Biology of the Cell
https://www.readbyqxmd.com/read/28329460/model-based-comparison-of-the-normal-and-fontan-circulatory-systems-part-iii
#12
Raymond L Watrous, Alvin J Chin
BACKGROUND: For patients with the Fontan circulatory arrangement, angiotensin-converting enzyme inhibition, guanylate cyclase activation, phosphodiesterase 5 inhibition, and endothelin receptor antagonism have so far resulted in little or no improvement in [Formula: see text] or peak cardiac index (CI), suggesting that our understanding of the factors that most impact the exercise hemodynamics is incomplete. METHODS: To facilitate comparisons with clinical reports of the exercise performance of preadolescent Fontan patients, we rescaled our previously reported computational models of a two-year-old normal child and similarly aged Fontan patient, extended our Fontan model to capture the nonlinear relationship between flow and resistance quantified from previous computational fluid dynamic analyses of the total cavopulmonary connection (TCPC), and added respiration as well as skeletal muscle contraction...
March 2017: World Journal for Pediatric & Congenital Heart Surgery
https://www.readbyqxmd.com/read/28327785/ultrastructural-alterations-in-schistosoma-mansoni-juvenile-and-adult-male-worms-after-in-vitro-incubation-with-primaquine
#13
Reem Osama A Kamel, Fatma El-Zahraa Anwar Bayaumy
BACKGROUND: Praziquantel has been cited as the only drug for treating schistosomiasis. However, concerns over drug resistance have encouraged the search for novel drug leads. The antimalarial drug primaquine possesses interesting anti-schistosmal properties. OBJECTIVES: This study is the first to document the potential role of primaquine as a schistosomicide and the ultrastructural changes induced by primaquine on juvenile or adult male worms of Schistosoma mansoni...
April 2017: Memórias do Instituto Oswaldo Cruz
https://www.readbyqxmd.com/read/28327410/mitochondria-control-acute-and-chronic-responses-to-hypoxia
#14
G S McElroy, N S Chandel
There are numerous mechanisms by which mammals respond to hypoxia. These include acute changes in pulmonary arterial tone due to smooth muscle cell contraction, acute increases in respiration triggered by the carotid body chemosensory cells, and chronic changes such as induction of red blood cell proliferation and angiogenesis by hypoxia inducible factor targets erythropoietin and vascular endothelial growth factor, respectively. Mitochondria account for the majority of oxygen consumption in the cell and have recently been appreciated to serve as signaling organelles required for the initiation or propagation of numerous homeostatic mechanisms...
March 19, 2017: Experimental Cell Research
https://www.readbyqxmd.com/read/28327161/rehabilitation-of-hand-function-after-spinal-cord-injury-using-a-novel-handgrip-device-a-pilot-study
#15
Haydn Hoffman, Tiffany Sierro, Tianyi Niu, Melanie E Sarino, Majid Sarrafzadeh, David McArthur, V Reggie Edgerton, Daniel C Lu
BACKGROUND: Activity-based therapy (ABT) for patients with spinal cord injury (SCI), which consists of repetitive use of muscles above and below the spinal lesion, improves locomotion and arm strength. Less data has been published regarding its effects on hand function. We sought to evaluate the effects of a weekly hand-focused therapy program using a novel handgrip device on grip strength and hand function in a SCI cohort. METHODS: Patients with SCI were enrolled in a weekly program that involved activities with the MediSens (Los Angeles, CA) handgrip...
March 21, 2017: Journal of Neuroengineering and Rehabilitation
https://www.readbyqxmd.com/read/28326563/early-structural-and-functional-signature-of-3-day-human-skeletal-muscle-disuse-using-the-dry-immersion-model
#16
Rémi Demangel, Loïc Treffel, Guillaume Py, Thomas Brioche, Allan F Pagano, Marie-Pierre Bareille, Arnaud Beck, Laurence Pessemesse, Robin Candau, Claude Gharib, Angèle Chopard, Catherine Millet
Microgravity and hypoactivity are associated with skeletal muscle deconditioning. The decrease of muscle mass is an exponential decay with major changes in the first days. The purpose of the study was to dissect out the effects of a short-term 3-day dry immersion (DI) on human quadriceps muscle function and structure. The DI model, by suppressing all support zones, accurately reproduces the effects of microgravity. Twelve healthy volunteers (32 ± 5 yrs) completed 3 days of DI. Muscle function was investigated through maximal voluntary contraction (MVC) tests and muscle viscoelasticity...
March 22, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28326550/from-neuron-to-behavior-sensory-motor-coordination-of-zebrafish-turning-behavior
#17
REVIEW
Keiko Umeda, Wataru Shoji
Recent development of optogenetics brought non-invasive neural activation in living organisms. Transparent zebrafish larva is one of the suitable animal models for this technique, which enables us to investigate neural circuits for behaviors based on a whole individual nervous system. In this article we review our recent finding that suggests sensory-motor coordination in larval zebrafish escape behavior. When water vibration stimulates mechanosensory Rohon-Beard (RB) neurons, intra-spinal reflex circuit launches contralateral trunk muscle contraction that makes rapid body curvature for turning...
March 21, 2017: Development, Growth & Differentiation
https://www.readbyqxmd.com/read/28326439/a-distinct-functional-distribution-of-%C3%AE-and-%C3%AE-motoneurons-in-the-rat-trigeminal-motor-nucleus
#18
Yukako Morita-Isogai, Hajime Sato, Mitsuru Saito, Eriko Kuramoto, Dong Xu Yin, Takeshi Kaneko, Takashi Yamashiro, Kenji Takada, Seog Bae Oh, Hiroki Toyoda, Youngnam Kang
Gamma-motoneurons (γMNs) play a crucial role in regulating isometric muscle contraction. The slow jaw-closing during mastication is one of the most functional isometric contractions, which is developed by the rank-order recruitment of alpha-motoneurons (αMNs) in a manner that reflects the size distribution of αMNs. In a mouse spinal motor nucleus, there are two populations of small and large MNs; the former was identified as a population of γMNs based on the positive expression of the transcription factor estrogen-related receptor 3 (Err3) and negative expression of the neuronal DNA-binding protein NeuN, and the latter as that of αMNs based on the opposite pattern of immunoreactivity...
March 22, 2017: Brain Structure & Function
https://www.readbyqxmd.com/read/28325813/aging-effects-of-caenorhabditis-elegans-ryanodine-receptor-variants-corresponding-to-human-myopathic-mutations
#19
Katie Nicoll Baines, Célia Ferreira, Philip M Hopkins, Marie-Anne Shaw, Ian A Hope
Delaying the decline in skeletal muscle function will be critical to better maintenance of an active life-style in old age. The skeletal muscle ryanodine receptor, the major intracellular membrane channel through which calcium ions pass to elicit muscle contraction, is central to calcium ion balance, and is hypothesized to be a significant factor for age-related decline in muscle function. The nematode Caenorhabditis elegans is a key model system for the study of human aging and strains with modified C. elegans ryanodine receptors corresponding to human myopathic variants linked with malignant hyperthermia and related conditions were generated...
March 21, 2017: G3: Genes—Genomes—Genetics
https://www.readbyqxmd.com/read/28325731/effects-of-genetic-deletion-of-soluble-5-nucleotidases-nt5c1a-and-nt5c2-on-ampk-activation-and-nucleotide-levels-in-contracting-mouse-skeletal-muscles
#20
Samanta Kviklyte, Didier Vertommen, Xavier Yerna, Harriet Andersén, Xiufeng Xu, Philippe Gailly, Mohammad Bohlooly-Y, Jan Oscarsson, Mark H Rider
AMP-activated protein kinase (AMPK) plays a key role in energy homeostasis and is activated in response to contraction-induced ATP depletion in skeletal muscle via a rise in intracellular AMP/ADP concentrations. AMP can be deaminated by AMP-deaminase to IMP, which is hydrolysed to inosine by cytosolic 5'-nucleotidase-II (NT5C2). AMP can also be hydrolysed to adenosine by cytosolic 5'-nucleotidase-IA (NT5C1A). Previous gene silencing and overexpression studies indicated control of AMPK activation by NT5C enzymes...
March 21, 2017: American Journal of Physiology. Endocrinology and Metabolism
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