Read by QxMD icon Read

Fast twitch

Carolyn J Baglole, Feng Liang, Hussein Traboulsi, Angela Rico de Souza, Christian Giordano, Josephine T Tauer, Frank Rauch, Basil J Petrof
BACKGROUND: Osteogenesis imperfecta (OI) is most often caused by mutations in type I collagen genes. Respiratory complications have been largely attributed to spine and ribcage deformities. We hypothesized that direct involvement of the pulmonary parenchyma and/or diaphragm by the disease may occur. METHODS: In Col1a1Jrt/+ mice, a model of severe dominant OI, mean linear intercept length (Lm) was used to assess distal airspace size. Cross-sectional area (CSA) and myosin heavy chain (MyHC) phenotype of diaphragm muscle fibers, as well as contractile properties, were determined...
March 14, 2018: Pediatric Research
Mehmet E Yalvac, Jakkrit Amornvit, Lei Chen, Kimberly M Shontz, Sarah Lewis, Zarife Sahenk
Neurotrophin 3 (NT-3) has well-recognized effects on peripheral nerve and Schwann cells, promoting axonal regeneration and associated myelination. In this study, we assessed the effects of AAV.NT-3 gene therapy on the oxidative state of the neurogenic muscle from the TremblerJ (TrJ ) mice at 16 weeks post-gene injection and found that the muscle fiber size increase was associated with a change in the oxidative state of muscle fibers towards normalization of the fiber type ratio seen in the wild type. NT-3-induced fiber size increase was most prominent for the fast twitch glycolytic fiber population...
March 9, 2018: Gene Therapy
William B Stoughton, Jianrong Li, Cindy Balog-Alvarez, Joe N Kornegay
Introduction Duchenne muscular dystrophy (DMD) and golden retriever muscular dystrophy (GRMD) are X-linked disorders caused by mutations in the DMD gene. Autophagy was recently identified as a secondary therapeutic target for DMD. We hypothesized that autophagy would be reduced in GRMD. Methods Autophagic gene and protein expression was assessed in normal and GRMD skeletal muscles and correlated with phenotypic biomarkers. Results Muscles were differentially affected. Autophagy gene levels were lower than normal in the GRMD cranial sartorius (CS) but similar in the vastus lateralis (VL)...
March 7, 2018: Muscle & Nerve
Hongbo Gao, Yi-Fan Li
Denervation induces skeletal muscle atrophy, which primarily impairs oxidative slow twitch fibers. The underlying mechanism of this phenomenon, however, remains to be addressed. We hypothesize that denervation-induced fiber-specific atrophy may result from the distinct activities of different signaling pathways that are involved in protein synthesis and degradation in fast- and slow-twitch fibers. In this study, 1-month-old male mice were subjected to unilateral sciatic denervation for 4 days. Fast-twitch muscle extensor digitorum longus (EDL) and slow-twitch muscle soleus were collected from the denervated side and the control side of hind limbs...
February 2018: Physiological Reports
Jennifer Chu, Frans Bruyninckx, Duncan V Neuhauser
Introduction: Favourable pain relief results on evoking autonomous twitches at myofascial trigger points with Electrical Twitch Obtaining Intramuscular Stimulation (ETOIMS). Aim: To document autonomic nervous system (ANS) dysfunction in Complex Regional Pain Syndrome (CRPS) from blood pressure (BP) and pulse/heart rate changes with ETOIMS. Methods and materials: A patient with persistent pain regularly received serial ETOIMS sessions of 60, 90, 120 or ≥150 min over 24 months...
July 2017: BMJ Innovations
Neil T Smith, Ana Soriano-Arroquia, Katarzyna Goljanek-Whysall, Malcolm J Jackson, Brian McDonagh
Age-related loss of muscle mass and function is associated with increased frailty and loss of independence. The mechanisms underlying the susceptibility of different muscle types to age-related atrophy are not fully understood. Reactive oxygen species (ROS) are recognised as important signalling molecules in healthy muscle and redox sensitive proteins can respond to intracellular changes in ROS concentrations modifying reactive thiol groups on Cysteine (Cys) residues. Conserved Cys residues tend to occur in functionally important locations and can have a direct impact on protein function through modifications at the active site or determining protein conformation...
February 10, 2018: Journal of Proteomics
Casper Skovgaard, Danny Christiansen, Peter M Christensen, Nicki W Almquist, Martin Thomassen, Jens Bangsbo
The aim of the present study was to examine whether improved running economy with a period of speed endurance training and reduced training volume could be related to adaptations in specific muscle fibers. Twenty trained male (n = 14) and female (n = 6) runners (maximum oxygen consumption (VO2 -max): 56.4 ± 4.6 mL/min/kg) completed a 40-day intervention with 10 sessions of speed endurance training (5-10 × 30-sec maximal running) and a reduced (36%) volume of training. Before and after the intervention, a muscle biopsy was obtained at rest, and an incremental running test to exhaustion was performed...
February 2018: Physiological Reports
Leonit Kiriaev, Sindy Kueh, John W Morley, Kathryn N North, Peter J Houweling, Stewart I Head
A striking pathological feature of dystrophinopathies is the presence of morphologically abnormal branched skeletal muscle fibers. The deterioration of muscle contractile function in Duchenne muscular dystrophy is accompanied by both an increase in number and complexity of these branched fibers. We propose that when number and complexity of branched fibers reaches a critical threshold, "tipping point" the branches in and of themselves are the site of contraction-induced rupture. In the present study, we use the dystrophic mdx mouse and littermate controls to study the pre-diseased dystrophic fast-twitch EDL muscle at 2-3-weeks, the peak myonecrotic phase at 6-9 weeks and finally "old" at 58-112 weeks...
February 7, 2018: American Journal of Physiology. Cell Physiology
Karsten Keller
Sarcopenia is a very common, but frequently overlooked and undertreated geriatric syndrome comprising pronounced muscle mass and strength/performance loss. Estimated prevalence is between 5 and 40% in the general population, accompanied by an exponential incline with increasing age. Sarcopenia is connected to atrophy and loss of muscle fibers and motor units, affecting primarily the fast-twitch muscle fibers und their motor units. Fast-twitch muscle fibers seem to be more prone to failure of function and loss over time...
February 6, 2018: Wiener Medizinische Wochenschrift
P S Sharp, N Tyreman, K Jones, T Gordon
Selective survival of small motor nerve fibers and their neuromuscular contacts in the SOD1G93A transgenic mouse model of amyotrophic lateral sclerosis (ALS) suggests that smaller regenerated nerve fibers are more able to sustain reformed nerve-muscle connections as functionally intact motor units (MUs). The sciatic nerve was crushed unilaterally in SOD1G93A transgenic mice at 40 days of age and contractile forces of reinnervated muscles and their MUs were recorded at 90 days in order to determine the capacities of the nerves to regenerate and to form and retain functional neuromuscular connections...
January 30, 2018: Neurobiology of Disease
Mariko Matsubara, Haruka Tohara, Koji Hara, Hiromichi Shinozaki, Yasuhiro Yamazaki, Chiaki Susa, Ayako Nakane, Yoko Wakasugi, Shunsuke Minakuchi
Purpose: This study was aimed to examine the effectiveness of a high-speed jaw-opening exercise, which targets the contraction of fast-twitch muscle fibers, in improving swallowing function. Subjects and methods: Twenty-one subjects (mean age 74.0±5.7 years) with dysphagia-related symptoms, such as coughing or choking during eating, performed the exercise. None of the included subjects had neurological symptoms or history of surgery that could cause significant dysphagia...
2018: Clinical Interventions in Aging
H P Patel, A Dawson, L D Westbury, G Hasnaoui, H E Syddall, S Shaw, A A Sayer, C Cooper, E M Dennison
Sarcopenia and osteoporosis are associated with poor health outcomes in older people. Relationships between muscle and bone have typically been reported at a functional or macroscopic level. The aims of this study were to describe the relationships between muscle morphology and bone health among participants of the Hertfordshire Sarcopenia Study (HSS). 105 older men, mean age 72.5 (SD 2.5) years, were recruited into the HSS. Whole body lean mass as well as appendicular lean mass, lumbar spine and femoral neck bone mineral content (BMC) and bone mineral density (BMD) were obtained through dual-energy X-ray absorptiometry scanning...
January 25, 2018: Calcified Tissue International
Jordan Bunda, William Gittings, Rene Vandenboom
Phosphorylation of the myosin regulatory light chain (RLC) by skeletal myosin light chain kinase (skMLCK) potentiates rodent fast twitch muscle but is an ATP requiring process. Our objective was to investigate the effect of skMLCK-catalyzed RLC phosphorylation on the energetic cost of contraction and the contractile economy (ratio of mechanical output to metabolic input) of mouse fast muscle in vitro (25° C). To this end, extensor digitorum longus (EDL) muscles from Wildtype and from skMLCK devoid (skMLCK-/-) mice were subjected to repetitive low-frequency stimulation (10 Hz for 15 s) to produce staircase potentiation of isometric twitch force after which muscles were quick frozen for determination of high-energy phosphate consumption (HEPC)...
January 4, 2018: Journal of Experimental Biology
Masato Yamauchi, Masahito Yamamoto, Kei Kitamura, Sumiharu Morita, Ryotaro Nagakura, Satoru Matsunaga, Shinichi Abe
In an attempt to clarify the function of the suboccipital muscles, we performed morphological observation of the suboccipital muscles for variations in the muscle belly and compared the morphology of their muscle fibers in terms of cross-sectional area by immunostaining with anti-myosin heavy chain antibodies. The cadavers of 25 Japanese individuals were used: 22 for morphological examinations and three for histological examinations. Among samples of the rectus capitis posterior major muscle (RCPma) and rectus capitis posterior minor muscle (RCPmi), 86...
December 2017: Anatomy & Cell Biology
Konark Bisht, Stefan Klumpp, Varsha Banerjee, Rahul Marathe
A human pathogen, Neisseria gonorrhoeae (NG), moves on surfaces by attaching and retracting polymeric structures called Type IV pili. The tug-of-war between the pili results in a two-dimensional stochastic motion called twitching motility. In this paper, with the help of real-time NG trajectories, we develop coarse-grained models for their description. The fractal properties of these trajectories are determined and their influence on first passage time and formation of bacterial microcolonies is studied. Our main observations are as follows: (i) NG performs a fast ballistic walk on small time scales and a slow diffusive walk over long time scales with a long crossover region; (ii) there exists a characteristic persistent length l_{p}^{*}, which yields the fastest growth of bacterial aggregates or biofilms...
November 2017: Physical Review. E
Shudai Lin, Xiran Lin, Zihao Zhang, Mingya Jiang, Yousheng Rao, Qinghua Nie, Xiquan Zhang
Copy number variations (CNVs), which cover many functional genes, are associated with complex diseases, phenotypic diversity and traits that are economically important to raising chickens. The sex-determining region Y-box 6 (Sox6) plays a key role in fast-twitch muscle fiber differentiation of zebrafish and mice, but it is still unknown whether SOX6 plays a role in chicken skeletal muscle development. We identified two copy number polymorphisms (CNPs) which were significantly related to different traits on the genome level in chickens by AccuCopy® and CNVplex® analyses...
January 17, 2018: Genes
Ariba Siddiqi, Sridhar Poosapadi Arjunan, Dinesh Kant Kumar
This study describes a new model of the force generated by tibialis anterior muscle with three new features: single-fiber action potential, twitch force, and pennation angle. This model was used to investigate the relative effects and interaction of ten age-associated neuromuscular parameters. Regression analysis (significance level of 0.05) between the neuromuscular properties and corresponding simulated force produced at the footplate was performed. Standardized slope coefficients were computed to rank the effect of the parameters...
January 16, 2018: Medical & Biological Engineering & Computing
J Matthew Kuczmarski, Jeff M Hord, Yang Lee, Vinicius Guzzoni, Dinah Rodriguez, Matthew S Lawler, Erika L Garcia-Villatoro, Dylan Holly, Patrick Ryan, Kristian Falcon, Marcela Garcia, Mariana Janini Gomes, James D Fluckey, John M Lawler
Mechanical unloading stimulates rapid changes in skeletal muscle morphology, characterized by atrophy of muscle fiber cross-sectional area (CSA) and a partial fiber-type shift from slow to fast-twitch. Recent studies revealed that oxidative stress contributes to activation of FoxO3a, proteolytic signaling and unloading-induced muscle atrophy via translocation of the mu-splice variant of neuronal nitric oxide synthase (nNOSμ) and activation of FoxO3a. Yet, there is limited understanding of the role of reactive oxygen species (ROS) on the Akt-mTOR pathway signaling during unloading...
January 8, 2018: Experimental Physiology
Angela J Gaboardi, Jochen Kressler, Teresa K Snow, Edward M Balog
INTRODUCTION: Because impaired excitation-contraction coupling and reduced sarcoplasmic reticulum Ca2+ release may contribute to the age-associated decline in skeletal muscle strength, we investigated the effect of aging on RyR1 regulation by physiological channel ligands. METHODS: [3 H]Ryanodine binding to membranes from 8 and 26 month old Fischer 344 extensor digitorum longus (EDL) and soleus muscles was used to investigate the effects of age on RyR1 modulation by Ca2+ and calmodulin (CaM)...
January 9, 2018: Muscle & Nerve
Maria Vromans, Pouran Faghri
This investigation aimed to determine the force and muscle surface electromyography (EMG) responses to different frequencies of electrical stimulation (ES) in two groups of muscles with different size and fiber composition (fast- and slow-twitch fiber proportions) during a fatigue-inducing protocol. Progression towards fatigue was evaluated in the abductor pollicis brevis (APB) and vastus lateralis (VL) when activated by ES at three frequencies (10, 35, and 50Hz). Ten healthy adults (mean age: 23.2 ± 3.0 years) were recruited; participants signed an IRB approved consent form prior to participation...
December 5, 2017: European Journal of Translational Myology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"