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https://www.readbyqxmd.com/read/29677344/interaction-between-pilocarpine-and-ripasudil-on-intraocular-pressure-pupil-diameter-and-the-aqueous-outflow-pathway
#1
Reiko Yamagishi-Kimura, Megumi Honjo, Takashi Komizo, Takashi Ono, Akiko Yagi, Jinhee Lee, Kazunori Miyata, Tomokazu Fujimoto, Toshihiro Inoue, Hidenobu Tanihara, Junko Nishida, Takatoshi Uchida, Yuka Araki, Makoto Aihara
Purpose: To explore interactions between pilocarpine and the ROCK inhibitor, ripasudil, on IOP and pupil diameter in human eyes, and morphological and functional changes in outflow tissues in vitro. Methods: IOP and pupil diameter were measured after pilocarpine and/or ripasudil, which were topically applied in healthy subjects. Human trabecular meshwork (HTM) cells were used in a gel contraction assay, for the evaluation of phosphorylation of myosin light chain and cofilin, and immunostaining for cytoskeletal proteins...
April 1, 2018: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/29677129/assessment-of-dry-epidermal-electrodes-for-long-term-electromyography-measurements
#2
Momona Yamagami, Keshia M Peters, Ivana Milovanovic, Irene Kuang, Zeyu Yang, Nanshu Lu, Katherine M Steele
Commercially available electrodes can only provide quality surface electromyography (sEMG) measurements for a limited duration due to user discomfort and signal degradation, but in many applications, collecting sEMG data for a full day or longer is desirable to enhance clinical care. Few studies for long-term sEMG have assessed signal quality of electrodes using clinically relevant tests. The goal of this research was to evaluate flexible, gold-based epidermal sensor system (ESS) electrodes for long-term sEMG recordings...
April 20, 2018: Sensors
https://www.readbyqxmd.com/read/29676836/visually-induced-analgesia-in-a-deep-tissue-experimental-pain-model-a-randomised-cross-over-experiment
#3
M J van Selm, W I Gibson, M J Travers, G L Moseley, D Hince, B M Wand
BACKGROUND: Visualizing one's own painful body part appears to have an effect on reported pain intensity. Furthermore, it seems that manipulating the size of the viewed image can determine the direction and extent of this phenomenon. When visual distortion has been applied to clinical populations the analgesic effects have been in opposition to those observed in some experimental pain models. To help resolve this problem we explored the effect of visualisation and magnification of the visual image on reported pain using a delayed onset muscle soreness (DOMS) pain model...
April 20, 2018: European Journal of Pain: EJP
https://www.readbyqxmd.com/read/29676616/laboratory-practical-to-study-the-differential-innervation-pathways-of-urinary-tract-smooth-muscle
#4
Benjamin E Rembetski, Caroline A Cobine, Bernard T Drumm
In the mammalian lower urinary tract, there is a reciprocal relationship between the contractile state of the bladder and urethra. As the bladder fills with urine, it remains relaxed to accommodate increases in volume, while the urethra remains contracted to prevent leakage of urine from the bladder to the exterior. Disruptions to the normal contractile state of the bladder and urethra can lead to abnormal micturition patterns and urinary incontinence. While both the bladder and urethra are smooth-muscle organs, they are differentially contracted by input from cholinergic and sympathetic nerves, respectively...
June 1, 2018: Advances in Physiology Education
https://www.readbyqxmd.com/read/29676609/generation-of-life-in-a-test-tube-albert-szent-gyorgyi-bruno-straub-and-the-discovery-of-actin
#5
Jack A Rall
This is a story about a great scientist, luck, great discovery that changed the future direction of muscle research, war, a clandestine war mission, postwar politics, and an attempt to rewrite scientific history. Albert Szent-Gyorgyi, at 44 yr of age, won the Nobel Prize in 1937 for his work on vitamin C and the establishment of the groundwork of the citric acid cycle. He now wanted to investigate one of the fundamental aspects of life and settled on the study of muscle contraction. The Szent-Gyorgyi laboratory in Hungary during World War II demonstrated that contraction could be reproduced in vitro by threads consisting of just two proteins, myosin and the newly discovered protein by Bruno Straub that they called actin...
June 1, 2018: Advances in Physiology Education
https://www.readbyqxmd.com/read/29676416/self-plied-and-twist-stable-carbon-nanotube-yarn-artificial-muscles-driven-by-organic-solvent-adsorption
#6
Kaiyun Jin, Silan Zhang, Susheng Zhou, Jian Qiao, Yanhui Song, Jiangtao Di, Dengsong Zhang, Qingwen Li
Artificial yarn/fiber muscles have recently attracted considerable interest for various applications. These muscles can provide large-stroke tensile and torsional actuations, resulting from inserted twists. However, tensional tethering of twisted muscles is generally needed to avoid muscle snarling and untwisting. In this paper a carbon nanotube (CNT) yarn muscle that is tethering-free and twist-stable is reported. The yarn muscle is prepared by allowing the self-plying of a coiled CNT yarn. When driven by acetone adsorption, this muscle shows decoupled actuations, which provide fast and reversible ∼13...
April 20, 2018: Nanoscale
https://www.readbyqxmd.com/read/29675685/laplace-based-modeling-of-fiber-orientation-in-the-tongue
#7
Arnold D Gomez, Nahla Elsaid, Maureen L Stone, Jiachen Zhuo, Jerry L Prince
Mechanical modeling of tongue deformation plays a significant role in the study of breathing, swallowing, and speech production. In the absence of internal joints, fiber orientations determine the direction of sarcomeric contraction and have great influence over real and simulated tissue motion. However, subject-specific experimental observations of fiber distribution are difficult to obtain; thus, models of fiber distribution are generally used in mechanical simulations. This paper describes modeling of fiber distribution using solutions of Laplace equations and compares the effectiveness of this approach against tractography from diffusion tensor magnetic resonance imaging...
April 19, 2018: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/29674667/a-mixed-periodic-paralysis-myotonia-mutant-p1158s-imparts-ph-sensitivity-in-skeletal-muscle-voltage-gated-sodium-channels
#8
Mohammad-Reza Ghovanloo, Mena Abdelsayed, Colin H Peters, Peter C Ruben
Skeletal muscle channelopathies, many of which are inherited as autosomal dominant mutations, include myotonia and periodic paralysis. Myotonia is defined by a delayed relaxation after muscular contraction, whereas periodic paralysis is defined by episodic attacks of weakness. One sub-type of periodic paralysis, known as hypokalemic periodic paralysis (hypoPP), is associated with low potassium levels. Interestingly, the P1158S missense mutant, located in the third domain S4-S5 linker of the "skeletal muscle", Nav1...
April 19, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29674523/efficient-high-throughput-screening-by-er-ca-2-measurement-to-identify-inhibitors-of-ryanodine-receptor-ca2-release-channels
#9
Takashi Murayama, Nagomi Kurebayashi, Mari Ikegami-Yuasa, Shuichi Mori, Yukina Suzuki, Ryunosuke Akima, Haruo Ogawa, Junji Suzuki, Kazunori Kanemaru, Hideto Oyamada, Yuji Kiuchi, Masamitsu Iino, Hiroyuki Kagechika, Takashi Sakurai
Genetic mutations in ryanodine receptors (RyRs), Ca2+-release channels in the sarcoplasmic reticulum essential for muscle contractions, cause various skeletal muscle and cardiac diseases. Because the main underlying mechanism of the pathogenesis is overactive Ca2+ release by gain-of-function of the RyR channel, inhibition of RyRs is expected to be a promising treatment for these diseases. Here, to identify inhibitors specific to skeletal muscle type 1 RyR (RyR1), we developed a novel high-throughput screening (HTS) platform using time-lapse fluorescence measurement of Ca2+ concentrations in the endoplasmic reticulum (ER) ([Ca2+]ER)...
April 19, 2018: Molecular Pharmacology
https://www.readbyqxmd.com/read/29673831/association-of-hypovitaminosis-d-with-triceps-brachii-muscle-fatigability-among-older-women-findings-from-the-epidos-cohort
#10
G Duval, Y Rolland, A M Schott, H Blain, P Dargent-Molina, S Walrand, G Duque, C Annweiler
BACKGROUND: Vitamin D affects physical performance in older adults. Its effects on muscles, notably on muscle strength, remain unclear. The objective of this cross-sectional study was to determine whether hypovitaminosis D is associated with triceps brachii muscle fatigability in community-dwelling older women. METHODS: A randomized subset of 744 women aged ≥75years from the EPIDOS cohort was categorized into two groups according to triceps brachii muscle fatigability, defined as loss of strength >5% between two consecutive maximal isometric voluntary contractions...
May 2018: Maturitas
https://www.readbyqxmd.com/read/29673242/study-of-muscle-contraction-induced-by-electrical-pulse-stimulation-and-nitric-oxide-in-c2c12-myotube-cells
#11
In Ho Lee, Yoon Jeong Lee, Hyobin Seo, Yi Seul Kim, Ju-Ock Nam, Byung-Duk Jeon, Tae-Dong Kwon
PURPOSE: This study aimed to examine the independent effect of electrical pulse stimulation(EPS) and nitric oxide(NO) on muscle contraction and their synergistic or combined effect on contraction phenomenon using C2C12 mouse skeletal muscle cells. METHODS: Some differentiated C2C12 myotube cells were untreated (control). Other cells did not receive EPS and did receive 0.5, 1.0, or 2.0 mM of the NO donor, S-nitroso-N-acetyl-penicillamine (SNAP; -E/S0.5, -E/S1.0, and -E/S2...
March 30, 2018: Journal of Exercise Nutrition & Biochemistry
https://www.readbyqxmd.com/read/29673065/insight-into-tetrodotoxin-blockade-and-resistance-mechanisms-of-na-v-1-2-sodium-channel-by-theoretical-approaches
#12
Lei Xu, Dayu Li, Junjie Ding, Li Pan, Xiaoqin Ding
Nav 1.2, a member of voltage-gated sodium channels (Nav s) that are responsible for the generation and propagation of action potentials along the cell membrane, and play a vital role in the process of information transmission within the nervous system and muscle contraction, is preferentially expressed in the central nervous system. As a potent and selective blocker of Nav s, tetrodotoxin (TTX) has been extensively studied in biological and chemical sciences, whereas the detailed mechanism by which it blocks nine Nav 1 channel subtypes remain elusive...
April 19, 2018: Chemical Biology & Drug Design
https://www.readbyqxmd.com/read/29672226/high-intensity-muscle-metaboreflex-activation-attenuates-cardiopulmonary-baroreflex-mediated-inhibition-of-muscle-sympathetic-nerve-activity
#13
Keisho Katayama, Jasdeep Kaur, Benjamin E Young, Thales C Barbosa, Shigehiko Ogoh, Paul J Fadel
Previous studies have shown that muscle sympathetic nerve activity (MSNA) is reduced during low- and mild-intensity dynamic leg exercise. It has been suggested that such inhibition is mediated by loading of the cardiopulmonary baroreceptors and that this effect is overridden by muscle metaboreflex activation with higher intensity exercise. However, limited data are available regarding the interaction between the cardiopulmonary baroreflex and the muscle metaboreflex. Therefore, we tested the hypothesis that cardiopulmonary baroreflex-mediated inhibition of MSNA is attenuated during high intensity muscle metaboreflex activation...
April 19, 2018: Journal of Applied Physiology
https://www.readbyqxmd.com/read/29672220/environmental-hypoxia-favors-myoblast-differentiation-and-fast-phenotype-but-blunts-activation-of-protein-synthesis-after-resistance-exercise-in-human-skeletal-muscle
#14
Olouyomi Gnimassou, Rodrigo Fernández-Verdejo, Matthew Brook, Damien Naslain, Estelle Balan, Mariwan Sayda, Jessica Cegielski, Henri Nielens, Anabelle Decottignies, Jean-Baptiste Demoulin, Kenneth Smith, Philip J Atherton, Marc Francaux, Louise Deldicque
We hypothesized that a single session of resistance exercise performed in moderate hypoxic (FiO2 : 14%) environmental conditions would potentiate the anabolic response during the recovery period spent in normoxia. Twenty subjects performed a 1-leg knee extension session in normoxic or hypoxic conditions. Muscle biopsies were taken 15 min and 4 h after exercise in the vastus lateralis of the exercised and the nonexercised legs. Blood and saliva samples were taken at regular intervals before, during, and after the exercise session...
April 19, 2018: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
https://www.readbyqxmd.com/read/29671103/role-of-ca-2-in-changing-active-force-during-intermittent-submaximal-stimulation-in-intact-single-mouse-muscle-fibers
#15
Lisa D Glass, Arthur J Cheng, Brian R MacIntosh
Fatigue of single mouse fibers during repeated high-frequency stimulation results initially from decreased Ca2+ sensitivity while free myoplasmic calcium concentration ([Ca2+ ]m ) increases, followed by decreasing [Ca2+ ]m . Recovery of active force with low-frequency stimulation is slow and persistent fatigue results from low [Ca2+ ]m . However, the consequences of intermittent submaximal contractions are not known. The aim of the present study was to investigate the changes in [Ca2+ ]m and active force during intermittent submaximal contractions and subsequent recovery...
April 18, 2018: Pflügers Archiv: European Journal of Physiology
https://www.readbyqxmd.com/read/29670564/biometric-and-emotion-identification-an-ecg-compression-based-method
#16
Susana Brás, Jacqueline H T Ferreira, Sandra C Soares, Armando J Pinho
We present an innovative and robust solution to both biometric and emotion identification using the electrocardiogram (ECG). The ECG represents the electrical signal that comes from the contraction of the heart muscles, indirectly representing the flow of blood inside the heart, it is known to convey a key that allows biometric identification. Moreover, due to its relationship with the nervous system, it also varies as a function of the emotional state. The use of information-theoretic data models, associated with data compression algorithms, allowed to effectively compare ECG records and infer the person identity, as well as emotional state at the time of data collection...
2018: Frontiers in Psychology
https://www.readbyqxmd.com/read/29669825/single-cardiac-ventricular-myosins-are-autonomous-motors
#17
Yihua Wang, Chen-Ching Yuan, Katarzyna Kazmierczak, Danuta Szczesna-Cordary, Thomas P Burghardt
Myosin transduces ATP free energy into mechanical work in muscle. Cardiac muscle has dynamically wide-ranging power demands on the motor as the muscle changes modes in a heartbeat from relaxation, via auxotonic shortening, to isometric contraction. The cardiac power output modulation mechanism is explored in vitro by assessing single cardiac myosin step-size selection versus load. Transgenic mice express human ventricular essential light chain (ELC) in wild- type (WT), or hypertrophic cardiomyopathy-linked mutant forms, A57G or E143K, in a background of mouse α-cardiac myosin heavy chain...
April 2018: Open Biology
https://www.readbyqxmd.com/read/29668388/neuromuscular-changes-of-the-aged-human-hamstrings
#18
Eric A Kirk, Kevin J Gilmore, Charles L Rice
Despite the life-long importance for posture and locomotion, neuromuscular properties of the hamstrings muscle have not been explored with adult ageing. The purpose was to assess and compare age-related effects on contractile function, spinal motor neuron output expressed as motor unit (MU) discharge rates in the hamstrings of 11 young (26 {plus minus} 4 y) and 10 old (80 {plus minus} 5 y) men. Maximal voluntary isometric contractions (MVC), stimulated contractile properties, surface and intramuscular electromyography (EMG) from sub-maximal to MVC were recorded in the biceps femoris (BF) and semimembranosus-semitendinosus (SS) muscles...
April 18, 2018: Journal of Neurophysiology
https://www.readbyqxmd.com/read/29668386/neck-muscle-biomechanics-and-neural-control
#19
Jason Bradley Fice, Gunter P Siegmund, Jean-Sebastien Blouin
The mechanics, morphometry, and geometry of our joints, segments and muscles are fundamental biomechanical properties intrinsic to human neural control. The goal of our study was to investigate if the biomechanical actions of individual neck muscles predicts their neural control. Specifically, we compared the moment direction & variability produced by electrical stimulation of a neck muscle (biomechanics) to their preferred activation direction & variability (neural control). Subjects sat upright with their head fixed to a 6-axis load cell and their torso restrained...
April 18, 2018: Journal of Neurophysiology
https://www.readbyqxmd.com/read/29668385/functional-properties-of-human-muscle-spindles
#20
Vaughan G Macefield, Thomas P Knellwolf
Muscle spindles are ubiquitous encapsulated mechanoreceptors found in most mammalian muscles. There are two types of endings, primary and secondary, and both are sensitive to changes in muscle length and velocity, with the primary endings having a greater dynamic sensitivity. Unlike other mechanoreceptors in the somatosensory system, muscle spindles are unique in possessing motor innervation, via  motoneurons (fusimotor neurons), that control their sensitivity to stretch. Much of what we know about human muscles spindles comes from studying the behavior of their afferents via intraneural microelectrodes (microneurography) inserted into accessible peripheral nerves...
April 18, 2018: Journal of Neurophysiology
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