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https://www.readbyqxmd.com/read/29656163/myofibrilar-functional-dysregulation-in-fish-a-new-biomarker-of-damage-to-pesticides
#1
Andrea C Crupkin, Fernando G Iturburu, Marcos Crupkin, Mirta L Menone
Endosulfan (ES) modifies the ultrastructure of skeletal muscle fibers and causes changes to the swimming behavior of fish. The objectives of the present work were to evaluate, in fishes of Australoheros facetus, 1) the integrity of myofibrils (Mf) by the analysis of SDS-PAGE profiles, and 2) the functionality of Mf through the microscopically monitoring of the contraction and changes in Mg2+ Ca2+ - ATPase and Mg2+ (EGTA) -ATPase activities. As expected, after the addition of the contraction buffer, control fish Mf contracted...
April 12, 2018: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/29655450/nature-and-action-of-antibodies-in-myasthenia-gravis
#2
REVIEW
Robert L Ruff, Robert P Lisak
This article discusses antibodies associated with immune-mediated myasthenia gravis and the pathologic action of these antibodies at the neuromuscular junctions of skeletal muscle. To explain how these antibodies act, we consider the physiology of neuromuscular transmission with emphasis on 4 features: the structure of the neuromuscular junction; the roles of postsynaptic acetylcholine receptors and voltage-gated Na+ channels and in converting the chemical signal from the nerve terminal into a propagated action potential on the muscle fiber that triggers muscle contraction; the safety factor for neuromuscular transmission; and how the safety factor is reduced in different forms of autoimmune myasthenia gravis...
May 2018: Neurologic Clinics
https://www.readbyqxmd.com/read/29655446/practical-anatomy-of-the-neuromuscular-junction-in-health-and-disease
#3
REVIEW
Hiroshi Nishimune, Kazuhiro Shigemoto
Neuromuscular junctions (NMJs) form between nerve terminals of spinal cord motor neurons and skeletal muscles, and perisynaptic Schwann cells and kranocytes cap NMJs. One muscle fiber has one NMJ, which is innervated by one motor nerve terminal. NMJs are excitatory synapses that use P/Q-type voltage-gated calcium channels to release the neurotransmitter acetylcholine. Acetylcholine receptors accumulate at the postsynaptic specialization called the end plate on the muscle fiber membrane, the sarcolemma. Proteins essential for the organization of end plates include agrin secreted from nerve terminals, Lrp4 and MuSK receptors for agrin, and Dok-7 and rapsyn cytosolic proteins in the muscle...
May 2018: Neurologic Clinics
https://www.readbyqxmd.com/read/29652764/our-surgical-repair-for-macrostomia-with-two-novel-small-triangular-flaps-long-term-follow-up-and-results
#4
Jumpei Tsumoto, Keisuke Imai, Takeshi Masuoka, Daisuke Sakahara, Koji Kawamoto, Songsu Kang, Masayuki Komune
BACKGROUND: The surgical methods for repairing congenital macrostomia should be carefully selected from both functional and aesthetic points of view. The surgical correction of macrostomia results in normal orbicularis oris function and symmetry of the repaired lip. Herein, we report our novel technique and the results obtained, assessed retrospectively. METHODS: Twelve primary cases of macrostomia underwent surgical repair between 1996 and 2013. The age at operation ranged from 3 to 78 months...
March 28, 2018: Plastic and Reconstructive Surgery
https://www.readbyqxmd.com/read/29652692/potential-roles-of-vascular-endothelial-growth-factor-during-skeletal-muscle-hypertrophy
#5
Kimberly A Huey
Vascular endothelial growth factor (VEGF) deletion in adult mouse muscle fibers contributes to impaired contractile and muscular adaptations to a hypertrophic stimulus suggesting a critical role in adult muscle growth. This review will explore the hypothesis that VEGF is essential for adult muscle growth by impacting inflammatory processes, satellite-endothelial cell interactions, and contractile protein accumulation by functioning within known hypertrophic signaling pathways including insulin-like growth factor-1 (IGF-1-Akt) and Wnt-ß-catenin...
April 12, 2018: Exercise and Sport Sciences Reviews
https://www.readbyqxmd.com/read/29651864/exogenous-skeletal-muscle-satellite-cells-promote-the-repair-of-levator-palpebrae-superioris-mechanical-damage-in-rat
#6
Lin Ye, Yuanyuan Yao, Hui Guo, Yun Peng
AIM OF THE STUDY: Blepharoptosis is a drooping of the upper eyelid, usually due to dysfunction of the levator palpebrae superioris (LPS). Recently, skeletal muscle satellite cells (SSCs) have been reported to promote the repair of damaged skeletal muscle. This study aims to investigate the potential contribution of exogenous SSCs to the regeneration of mechanically damaged LPS. MATERIALS AND METHODS: Thirty-two rats were randomly divided into four groups, including control group, SSCs-treated group, SSCs-treated injury group and non-treated injury group...
April 13, 2018: Connective Tissue Research
https://www.readbyqxmd.com/read/29649184/immunopathological-characterization-of-muscle-biopsy-samples-from-immune-mediated-necrotizing-myopathy-patients
#7
Qiong Wang, Yue Li, Suqiong Ji, Fang Feng, Bitao Bu
BACKGROUND Immune-mediated necrotizing myopathy (IMNM) is a relatively new proposed category of idiopathic inflammatory myopathies (IIMs), characterized by the presence of abundant necrotic muscle fibers, myophagocytosis, and sparse inflammatory infiltrates. The aim of our study was to analyze the immunopathological characteristics of IMNM by detecting biopsy samples from a cohort of patients, and to delineate the pathways involved in the pathogenesis. MATERIAL AND METHODS A retrospective evaluation of muscle biopsy samples, clinical and laboratory data, and immunohistochemical analysis of macrophages MHC-I and MAC, was performed for all patients diagnosed as having IMNM but without a prior exposure to statins...
April 12, 2018: Medical Science Monitor: International Medical Journal of Experimental and Clinical Research
https://www.readbyqxmd.com/read/29649068/is-exercise-the-right-medicine-for-dystrophic-muscle
#8
Hannah R Spaulding, Joshua T Selsby
INTRODUCTION: Duchenne muscular dystrophy (DMD) is a neuromuscular disease caused by a dystrophin protein deficiency. Dystrophin functions to stabilize and protect the muscle fiber during muscle contraction, thus the absence of functional dystrophin protein leads to muscle injury. DMD patients experience progressive muscle necrosis, loss of function, and ultimately succumb to respiratory failure or cardiomyopathy. Exercise is known to improve muscle health and strength in healthy individuals as well as positively impact other systems...
April 11, 2018: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/29629427/reference-values-for-shear-wave-elastography-of-neck-and-shoulder-muscles-in-healthy-individuals
#9
Caroline Ewertsen, Jonathan Carlsen, Mohammed Aftab Perveez, Henrik Schytz
Purpose: to establish reference values for ultrasound shear-wave elastography for pericranial muscles in healthy individuals (m. trapezius, m. splenius capitis, m. semispinalis capitis, m. sternocleidomastoideus and m. masseter). Also to evaluate day-to-day variations in the shear-wave speeds and evaluate the effect of the pennation of the muscle fibers, ie scanning parallel or perpendicularly to the fibers. Materials and Methods: 10 healthy individuals (5 males and 5 females) had their pericranial muscles examined with shear-wave elastography in two orthogonal planes on two different days for their dominant and non-dominant side...
January 2018: Ultrasound International Open
https://www.readbyqxmd.com/read/29627324/from-excitation-to-intracellular-ca-2-movements-in-skeletal-muscle-basic-aspects-and-related-clinical-disorders
#10
REVIEW
Bruno Allard
In skeletal muscle fiber, excitation-contraction coupling corresponds to the sequence of events occurring from action potential firing to initiation of contraction by an increase in cytosolic Ca2+ . These events are elicited in response to excitation of the motor neuron which induces trains of action potentials in the muscle cell that spread along the sarcolemma and in depth along the T-tubule membrane. Depolarization of the T-tubule membrane induces a conformational change in a protein complex, called the dihydropyridine receptor, which opens a calcium channel anchored in the membrane of the sarcoplasmic reticulum, called the ryanodine receptor, in charge of release of Ca2+ ions that activate contractile proteins...
March 9, 2018: Neuromuscular Disorders: NMD
https://www.readbyqxmd.com/read/29626373/sex-dimorphism-of-substrate-utilization-differences-in-skeletal-muscle-mitochondrial-volume-density-and-function
#11
David Montero, Klavs Madsen, Anne-Kristine Meinild-Lundby, Fredrik Edin, Carsten Lundby
Fat oxidation during exercise is higher in females than males. We sought to determine whether sex differences in substrate metabolism are paralleled by distinct skeletal muscle mitochondrial volume density and oxidative capacity. Whole-body substrate (fat, carbohydrate (CHO)) utilization during submaximal treadmill running was assessed and skeletal muscle biopsies were taken to determine mitochondrial volume density (MitoVD ) and function in healthy young females (n = 12) and males (n = 12) matched by aerobic exercise capacity (VO2max ) and exercise performance...
April 6, 2018: Experimental Physiology
https://www.readbyqxmd.com/read/29625506/factors-associated-with-delayed-bleeding-after-resection-of-large-nonpedunculated-colorectal-polyps
#12
Timothy R Elliott, Zacharias P Tsiamoulos, Siwan Thomas-Gibson, Noriko Suzuki, Leonidas A Bourikas, Ailsa Hart, Paul Bassett, Brian P Saunders
BACKGROUND:  Delayed bleeding is the most common significant complication after piecemeal endoscopic mucosal resection (p-EMR) of large nonpedunculated colorectal polyps (NPCPs). Risk factors for delayed bleeding are incompletely defined. We aimed to determine risk factors for delayed bleeding following p-EMR. METHODS:  Data were analyzed from a prospective tertiary center audit of patients with NPCPs ≥ 20 mm who underwent p-EMR between 2010 and 2012...
April 6, 2018: Endoscopy
https://www.readbyqxmd.com/read/29623933/electroacupuncture-and-moxibustion-promote-regeneration-of-injured-sciatic-nerve-through-schwann-cell-proliferation-and-nerve-growth-factor-secretion
#13
Lin-Na Hu, Jin-Xin Tian, Wei Gao, Jing Zhu, Fang-Fang Mou, Xiao-Chun Ye, Yu-Pu Liu, Ping-Ping Lu, Shui-Jin Shao, Hai-Dong Guo
Using electroacupuncture and moxibustion to treat peripheral nerve injury is highly efficient with low side effects. However, the electroacupuncture- and moxibustion-based mechanisms underlying nerve repair are still unclear. Here, in vivo and in vitro experiments uncovered one mechanism through which electroacupuncture and moxibustion affect regeneration after peripheral nerve injury. We first established rat models of sciatic nerve injury using neurotomy. Rats were treated with electroacupuncture or moxibustion at acupoints Huantiao (GB30) and Zusanli (ST36)...
March 2018: Neural Regeneration Research
https://www.readbyqxmd.com/read/29621305/biomarkers-associated-with-low-moderate-and-high-vastus-lateralis-muscle-hypertrophy-following-12-weeks-of-resistance-training
#14
Christopher B Mobley, Cody T Haun, Paul A Roberson, Petey W Mumford, Wesley C Kephart, Matthew A Romero, Shelby C Osburn, Christopher G Vann, Kaelin C Young, Darren T Beck, Jeffrey S Martin, Christopher M Lockwood, Michael D Roberts
We sought to identify biomarkers which delineated individual hypertrophic responses to resistance training. Untrained, college-aged males engaged in full-body resistance training (3 d/wk) for 12 weeks. Body composition via dual x-ray absorptiometry (DXA), vastus lateralis (VL) thickness via ultrasound, blood, VL muscle biopsies, and three-repetition maximum (3-RM) squat strength were obtained prior to (PRE) and following (POST) 12 weeks of training. K-means cluster analysis based on VL thickness changes identified LOW [n = 17; change (mean±SD) = +0...
2018: PloS One
https://www.readbyqxmd.com/read/29620464/the-effect-of-the-wooden-breast-myopathy-on-sarcomere-structure-and-organization
#15
Sandra G Velleman, Daniel L Clark, Jeffrey R Tonniges
The wooden breast (WB) has been classically identified by the phenotypic presence of a wood-like pectoralis major (p. major) muscle. The WB-affected p. major muscle is characterized by necrotic muscle fibers and the replacement of muscle with connective tissue, water, and fat. The objective of the current study was to determine the effect of the WB myopathy on sarcomere organization by transmission electron microscopy. Sarcomere structure and organization were examined in two broiler lines with a high incidence of WB (Lines A and B) and another broiler line without WB (Line C)...
March 2018: Avian Diseases
https://www.readbyqxmd.com/read/29617946/long-term-selection-of-chickens-for-body-weight-alters-muscle-satellite-cell-behaviors
#16
A E Geiger, M R Daughtry, C M Gow, P B Siegel, H Shi, D E Gerrard
Muscle satellite cells (SC) are resident stem-like cells that play an integral role in skeletal muscle growth and repair. Understanding how SC maintain their identities and dynamic properties is critical to animal growth. However, the genetic and environmental factors governing SC behaviors and the underpinning mechanisms remain unknown. To explore whether genetic selection influences SC behaviors, we used 2 lines of chickens selected for over 50 generations with over a 10-fold difference in body weight at 56 d of age-the Virginia high weight selection (HWS) and low weight selection (LWS) lines...
April 3, 2018: Poultry Science
https://www.readbyqxmd.com/read/29615556/ethanol-exposure-causes-muscle-degeneration-in-zebrafish
#17
Elizabeth C Coffey, Maggie E Pasquarella, Michelle F Goody, Clarissa A Henry
Alcoholic myopathies are characterized by neuromusculoskeletal symptoms such as compromised movement and weakness. Although these symptoms have been attributed to neurological damage, EtOH may also target skeletal muscle. EtOH exposure during zebrafish primary muscle development or adulthood results in smaller muscle fibers. However, the effects of EtOH exposure on skeletal muscle during the growth period that follows primary muscle development are not well understood. We determined the effects of EtOH exposure on muscle during this phase of development...
March 9, 2018: Journal of Developmental Biology
https://www.readbyqxmd.com/read/29614796/voluntary-exercise-positively-affects-the-recovery-of-long-nerve-gap-injury-following-tube-bridging-with-human-skeletal-muscle-derived-stem-cell-transplantation
#18
Hiroya Seta, Daisuke Maki, Akihito Kazuno, Ippei Yamato, Nobuyuki Nakajima, Shuichi Soeda, Yoshiyasu Uchiyama, Tetsuro Tamaki
The therapeutic effects of voluntary exercise on the recovery of long-gap nerve injury following the bridging of an acellular conduit filled with human skeletal muscle-derived stem cells (Sk-SCs) have been described. Human Sk-SCs were sorted as CD34⁺/45- (Sk-34) cells, then cultured/expanded under optimal conditions for 2 weeks. Surgery to generate a long-gap sciatic nerve injury was performed in athymic nude mice, after which the mice were divided into exercise (E) and non-exercise (NE) groups. The mice were housed in standard individual cages, and voluntary exercise wheels were introduced to the cages of the E group one week after surgery...
April 2, 2018: Journal of Clinical Medicine
https://www.readbyqxmd.com/read/29609262/-multiple-factors-analysis-of-early-postpartum-pelvic-floor-muscles-injury-in-regenerated-parturients
#19
M Li, J Shi, Q P Lü, F H Wei, T Z Gai, Q Feng
Objective: To investigate the risk factors for multiparous pelvic floor muscles injury during 6-8 weeks after delivery. Method: From June 2015 to April 2017, 1917 women (1 523 primigravidas and 294 multiparas) were accepted postpartum pelvic floor function screening during 6-8 weeks after delivery in Beijing Hospital.Pelvic examination and pelvic floor muscle strength testing were carried out in these women.All the data were analyzed with multivariate logistic regression method to explore the related factors for postpartum pelvic floor muscle injury...
March 20, 2018: Zhonghua Yi Xue za Zhi [Chinese medical journal]
https://www.readbyqxmd.com/read/29600773/source-sink-mismatch-causing-functional-conduction-block-in-re-entrant-ventricular-tachycardia
#20
REVIEW
Edward J Ciaccio, James Coromilas, Andrew L Wit, Nicholas S Peters, Hasan Garan
Ventricular tachycardia (VT) caused by a re-entrant circuit is a life-threatening arrhythmia that at present cannot always be treated adequately. A realistic model of re-entry would be helpful to accurately guide catheter ablation for interruption of the circuit. In this review, models of electrical activation wavefront propagation during onset and maintenance of re-entrant VT are discussed. In particular, the relationship between activation mapping and maps of transition in infarct border zone thickness, which results in source-sink mismatch, is considered in detail and supplemented with additional data...
January 2018: JACC. Clinical Electrophysiology
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