Signal transducer and activator of transcription 3 (STAT3) is involved in cytokine- and nutrient-induced insulin resistance. The role of STAT3 in the development of skeletal muscle insulin resistance and type 2 diabetes (T2D) pathogenesis is incompletely defined. We tested the hypothesis that STAT3 signaling contributes to skeletal muscle insulin resistance in T2D. Protein abundance and phosphorylation of STAT3 signaling molecules were determined in skeletal muscle biopsy specimens from BMI- and age-matched overweight individuals with normal glucose tolerant (NGT) and T2D patients. The direct role of STAT3 in the development of lipid-induced skeletal muscle insulin resistance was determined using small interfering (si)RNA. Phosphorylated STAT3, phosphorylated Janus kinase 2 (JAK2), and suppressor of cytokine signaling 3 (SOCS3) protein abundance was increased in skeletal muscle from T2D patients. STAT3 phosphorylation positively correlated with free fatty acid level and measures of insulin ...
Disclosed is a composition for promoting local muscle growth or slowing down or preventing local muscle atrophy, which composition contains a polypeptide in the C2 region of the enterotoxin Staphylococcus aureus and a myostatin polypeptide. By means of the composition, the defect in the prior art of only systemic muscle growth being possible has been overcome so as to achieve effects of promoting local muscle growth, or slowing down or preventing local muscle atrophy.
Muscle chart series - just charts at muscles. Skeletal Muscle Chart allowed in order to my personal website, in this particular time period I will demonstrate about Skeletal muscle chart.. And after this, this is the initial graphic, skeletal muscle chart, skeletal muscle diagram, skeletal muscle diagram labeled, skeletal muscle diagram quiz, skeletal muscle diagram worksheet, skeletal muscle diagram posterior, skeletal muscle mass chart, skeletal muscle measurement chart, skeletal muscle identification chart, skeletal muscle flow chart :. ...
Studying Rac1. The activation of Rac1 causes reorganization of cell components creating "highways" that allow other proteins such as glucose transport 4 or GLUT4 to relocate to the cell membrane and allow sugar from blood to enter skeletal muscle cells for processing. Consequently, Rac1 shows increased activity in response to insulin and exercise promoting the metabolism and storage of sugar in skeletal muscle. Harrison suspects that the dysfunction of Rac1 may play a large role in insulin resistance, and his lab is looking to better understand the dysfunction of skeletal muscle physiology that may contribute to insulin resistance. To study insulin resistance, Harrison is currently comparing Rac1 activity in skeletal muscle cells and skeletal muscle tissue of lean and obese mice. Learn more about Rac1, GO TO ARTICLE.. Harrison has always been drawn to human health, and is particularly intrigued by how adaptable the human body is. He completed his undergraduate degree and Masters in Exercise ...
Antioxidants are assumed to provide numerous benefits, including better health, a reduced rate of aging, and improved exercise performance. Specifically, antioxidants are commonly "prescribed" by the media, supplement industry, and "fitness experts" for individuals prior to training and performance, with assumed benefits of improved fatigue resistance and recovery. This has provoked expansion of the supplement industry which responded by creation of a plethora of products aimed at facilitating the needs of the active individual. However, what does the experimental evidence say about the efficacy of antioxidants on skeletal muscle function? Are antioxidants actually as beneficial as the general populous believes? Or, could they in fact lead to deleterious effects on skeletal muscle function and performance? This Mini Review addresses these questions with an unbiased look at what we know about antioxidant effects on skeletal muscle, and what we still need to know before conclusions can be made. ...
C57BL/6-GFP Mouse Skeletal Muscle Microvascular Endothelial Cells from Creative Bioarray are isolated from C57BL/6-Tg (CAG-EGFP) 1Osb/J mouse skeletal muscle tissue of pathogen-free laboratory mice. C57BL/6-GFP Mouse Skeletal Muscle Microvascular Endothelial Cells are grown in T25 tissue culture flasks pre-coated with gelatin-based coating solution for 2 min and incubated in Creative Bioarray Culture Complete Growth Medium generally for 3-7 days. Cultures are then expanded. Prior to shipping, cells are detached from flasks and immediately cryo-preserved in vials. Each vial contains at least 1x10^6 cells per ml and are delivered frozen. The method we use to isolate endothelial cells was developed based on a combination of established and our proprietary methods. These cells are pre-coated with PECAM-1 antibody, following the application of magnetic pre-coated with secondary antibody ...
Poststroke plantar flexor muscle weakness has been attributed to muscle atrophy and impaired activation, which cannot collectively explain the limitations in force-generating capability of the entire muscle group. It is of interest whether changes in poststroke plantar flexor muscle fascicle length and pennation angle influence the individual force-generating capability and whether plantar flexor weakness is due to uniform changes in individual muscle force contributions. Fascicle lengths and pennation angles for the soleus, medial, and lateral gastrocnemius were measured using ultrasound and compared between ten hemiparetic poststroke subjects and ten healthy controls. Physiological cross-sectional areas and force contributions to poststroke plantar flexor torque were estimated for each muscle. No statistical differences were observed for any muscle fascicle lengths or for the lateral gastrocnemius and soleus pennation angles between paretic, nonparetic, and healthy limbs. There was a significant
Human muscle cell line - human body diagram at muscles. Human Muscle Cell Line encouraged for you to our website, on this period I am going to teach you with regards to Human muscle cell line.. Now, this can be a very first image, human muscle cell line, human muscle cell line atcc, human smooth muscle cell line, human skeletal muscle cell line atcc, human cardiac muscle cell line, human heart muscle cell line, human vascular smooth muscle cell line, human airway smooth muscle cell line, human skeletal muscle myoblast cell line, immortalized human skeletal muscle cell line :. ...
TY - JOUR. T1 - Effects of intermittent pressure imitating rolling manipulation on calcium ion homeostasis in human skeletal muscle cells. AU - Zhang, Hong. AU - Liu, Howe. AU - Lin, Qing. AU - Zhang, Guohui. AU - Mason, David C.. PY - 2016/8/26. Y1 - 2016/8/26. N2 - Background: Homeostasis imbalance of intracellular Ca2+ is one of the key pathophysiological factors in skeletal muscle injuries. Such imbalance can cause significant change in the metabolism of Ca2+-related biomarkers in skeletal muscle, such as superoxide dismutase (SOD), malondialdehyde (MDA) and creatine kinase (CK). Measurements of these biomarkers can be used to evaluate the degree of damage to human skeletal muscle cells (HSKMCs) injury. Rolling manipulation is the most popular myofascial release technique in Traditional Chinese Medicine. The mechanism of how this technique works in ameliorating muscle injury is unknown. This study aimed to investigate the possible Ca2+ mediated effects of intermittent pressure imitating ...
Mouse Skeletal Muscle Cells are isolated form normal mouse skeletal muscle tissue. T25 flasks is required for cell adhension to the culture vessels. Grow cells in ECM-coated culture vessels with 5% CO2. Each vial contains at least 1x10^6 cells per ml ...
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Skeletal muscle mass and strength are crucial determinants of health. Muscle mass loss is associated with weakness, fatigue, and insulin resistance. In fact, it is predicted that controlling muscle atrophy can reduce morbidity and mortality associated with diseases such as cancer cachexia and sarcopenia. We analyzed gene expression data from muscle of mice or human patients with diverse muscle pathologies and identified LMCD1 as a gene strongly associated with skeletal muscle function. We transiently expressed or silenced LMCD1 in mouse gastrocnemius muscle or in mouse primary muscle cells and determined muscle/cell size, targeted gene expression, kinase activity with kinase arrays, protein immunoblotting, and protein synthesis levels. To evaluate force, calcium handling, and fatigue, we transduced the flexor digitorum brevis muscle with a LMCD1-expressing adenovirus and measured specific force and sarcoplasmic reticulum Ca2+ release in individual fibers. Finally, to explore the relationship between
In DMD and many other types of muscular dystrophies, cardiac and skeletal muscles are both compromised. The interplay between heart disease and skeletal muscle disease remains to be fully appreciated. It is generally agreed that normalizing skeletal muscle function alone cannot halt heart disease (Muntoni et al. 1995; Towbin et al. 1993; Townsend et al. 2007; Zhu et al. 2002). Limb muscles and respiratory muscles (in particular, the diaphragm) are auxiliary pumps that promote venous return. When skeletal muscle contractility is severely compromised (such as in m-dko mice), cardiac output will decrease as a consequence of reduced venous return. This seems to suggest that treating skeletal muscle alone should increase cardiac output and improve heart function. If left unchecked, severe skeletal muscle disease will aggravate cardiomyopathy. This argument is supported by findings from two clinical studies (Hunsaker et al. 1982; Matsuda et al. 1977). Hunsaker et al. (1982) followed nine ambulant DMD ...
The use of hormone replacement therapy (HRT) is a potential treatment to relieve symptoms of menopause and prevent the onset of disease such as osteoporosis in postmenopausal women. Although estrogen has a possible protective effect against exercise-induced skeletal muscle damage, it is unclear if HRT enhances estrogen receptor (ER) transcriptional activity in skeletal muscle at rest and following resistance exercise. We sought to evaluate changes in the gene expression of ER coregulators (SRC-1 and SMRT) and markers of skeletal muscle damage (CK, LDH, and TNF-α) in postmenopausal women following a high-intensity resistance exercise bout. Fourteen postmenopausal women were divided into two groups: Control, women not using HRT (n=6, 59±4 yr, 63±17 kg), or HRT, women using traditional HRT (n=8, 59±4 yr, 89±24 kg). Both groups performed 10 sets of 10 maximal eccentric repetitions of single-leg extension on the Cybex dynamometer at 60°/s with 20 second rest periods between sets. Muscle ...
Previous studies have shown that nitric oxide synthase (NOS), the enzyme that catalyzes the formation of nitric oxide (NO), is expressed in skeletal muscle. The aim of the present study was to test the hypothesis that NO can modulate glucose metabolism in slow- and fast-twitch skeletal muscles. Calcium-dependent NOS was detected in skeletal muscle, and the enzyme activity was greater in fast-type extensor digitorum longus (EDL) muscles than in slow-type soleus muscles. Both the neuronal-type (nNOS) and endothelial-type (eNOS) enzymes are expressed in resting skeletal muscles. However, nNOS protein was only detected in EDL muscles, whereas eNOS protein contents were comparable in soleus and EDL muscles. NOS expression in muscle cryosections (diaphorase histochemistry) was located in vascular endothelium and in muscle fibers, and the staining was greater in type lib than in type I and Ha fibers. The macrophage-type inducible NOS (iNOS) was not detected in resting muscle, but endotoxin treatment ...
TY - JOUR. T1 - Age- and stroke-related skeletal muscle changes a review for the geriatric clinician. AU - Sions, Jaclyn Megan. AU - Tyrell, Christine M.. AU - Knarr, Brian A.. AU - Jancosko, Angela. AU - Binder-Macleod, Stuart A.. PY - 2012/7/1. Y1 - 2012/7/1. N2 - Independently, aging and stroke each have a significant negative impact on skeletal muscle, but the potential cumulative effects of aging and stroke have not been explored. Optimal interventions for individuals post-stroke may include those that specifically target skeletal muscle. Addressing changes in muscles may minimize activity limitations and enhance participation post stroke. This article reviews the impact of aging and stroke on muscle morphology and composition, including fiber atrophy, reductions in muscle cross-sectional area, changes in muscle fiber distributions, and increases in intramuscular fat. Relationships between changes in muscle structure, muscle function, and physical mobility are reviewed. Clinical ...
Mitochondrial dysfunction develops in skeletal muscle with aging and may contribute to insulin resistance, which increases cardiovascular risk. A link between skeletal muscle insulin resistance and perturbed mitochondrial fusion and fission has been suggested but not proven. Optic Atrophy 1 (OPA1) is an inner mitochondrial membrane protein that plays a fundamental role in mitochondrial fusion, quality control and respiratory function. OPA1 levels are reduced in muscle from elderly subjects; however, the specific roles of OPA1 in the aging muscle have not been studied. We, therefore, generated a mouse model with inducible deletion of the OPA1 gene in skeletal muscle of adult C57Bl6 mice, by crossing OPA1 floxed mice with HSA-Cre (ERT2) mice (KO). Four-week-old KO and wild-type (WT) mice were treated with tamoxifen for 5 days to induce recombination, resulting in a 60% reduction in OPA1 protein levels 8 weeks after treatment (12-wk-old mice). OPA1 deficiency resulted in altered mitochondrial ...
It has been demonstrated that skeletal muscle adaptions, including muscle fibers transition, angiogenesis, and mitochondrial biogenesis are involved in the regular exercise-induced improvement of endurance capacity and metabolic status. Herein, we investigated the effects of pterostilbene (PST) supplementation on skeletal muscle adaptations to exercise training in rats. Six-week-old male Sprague Dawley rats were randomly divided into a sedentary control group (Sed), an exercise training group (Ex), and exercise training combined with 50 mg/kg PST (Ex + PST) treatment group. After 4 weeks of intervention, an exhaustive running test was performed, and muscle fiber type transformation, angiogenesis, and mitochondrial content in the soleus muscle were measured. Additionally, the effects of PST on muscle fiber transformation, paracrine regulation of angiogenesis, and mitochondrial function were tested in vitro using C2C12 myotubes. In vivo study showed that exercise training resulted in significant increases
Combining detailed musculoskeletal models and simulations with empirical data allows for the estimation of quantities that can greatly enhance our understanding of specific functional roles during dynamic movements [28,29,51]. Although anatomical and EMG studies can provide insight into muscle classification relative to gait events (e.g. stance versus swing phase), a detailed understanding of a muscles functional role(s) requires additional quantities that are not readily obtained using experimental techniques. The musculotendon force and mechanical work data generated in this study enable the determination of specific muscle mechanical roles such as motor, brake, strut or spring during gait [19-21]. These roles provide important information regarding how energy flows through the limb and generates the required external work during movement. Muscle functional roles were also mainly insensitive to optimization approach or gait type (table 4).. However, there were some subtle differences between ...
Quantification of skeletal muscle damage in response to injurious stretch-shortening cycles (SSCs) would be beneficial in elucidating the effect of different biomechanical exposures on the amount of muscle damage. Purpose: To investigate the effect of stretch-shortening cycle range of motion (ROM) on skeletal muscle damage in rats. Methods: Testing was performed on the dorsiflexor muscles of Spra
TY - JOUR. T1 - Validity of ultrasound muscle thickness measurements for predicting leg skeletal muscle mass in healthy Japanese middle-aged and older individuals. AU - Takai, Yohei. AU - Ohta, Megumi. AU - Akagi, Ryota. AU - Kato, Emika. AU - Wakahara, Taku. AU - Kawakami, Yasuo. AU - Fukunaga, Tetsuo. AU - Kanehisa, Hiroaki. PY - 2013/9/25. Y1 - 2013/9/25. N2 - Background: The skeletal muscle mass of the lower limb plays a role in its mobility during daily life. From the perspective of physical resources, leg muscle mass dominantly decreases after the end of the fifth decade. Therefore, an accurate estimate of the muscle mass is important for the middle-aged and older population. The present study aimed to clarify the validity of ultrasound muscle thickness (MT) measurements for predicting leg skeletal muscle mass (SM) in the healthy Japanese middle-aged and older population.Findings: MTs at four sites of the lower limb and the bone-free lean tissue mass (LTM) of the right leg were determined ...
We are interested in how skeletal muscle processes fat and its effect on insulin resistance. This is an important question since insulin resistance predates and predicts type 2 diabetes. We know that if pharmaceutical grade lipid is infused into people, they develop insulin resistance. Thus, we would like to infuse pharmaceutical grade lipid into trained subjects, believing that trained subjects will develop less insulin resistance, less decline in muscle energy function, and less accumulation of fat metabolites than untrained subjects. For comparing the effects of the pharmaceutical grade fat infusion, we will also have a group of trained and untrained subjects given a control (glycerol) infusion. Glycerol is basically the same as pharmaceutical grade lipid infusion without the lipid component.. Three visits will be required. The first visit will involve measurement of fitness. A second visit will involve measurement of insulin resistance. The third visit will involve an inpatient stay, with a ...
|P|Skeletal Muscle is a peer-reviewed, open access, online journal that publishes articles investigating molecular mechanisms underlying the biology of skeletal muscle. A wide range of skeletal muscle biology is included: development, metabolism, the regulation of mass and function, aging, degeneration, dystrophy and regeneration. The emphasis is on understanding adult skeletal muscle, its maintenance, and its interactions with non-muscle cell types and regulatory modulators.|/P| |P|Skeletal Muscle aims to provide a venue for the publication of novel, cutting-edge research and technological developments involving the application of molecular biology, cellular biology, and biochemistry-based approaches, and to answer questions relevant to the understanding of skeletal muscle.|/P|
- know that the main function of muscle is movement - know what the word contract/contraction means - know where you find skeletal muscle - know what the term myocyte is - know that skeletal muscle cells are as long as the belly of the muscle - know that the word striation means stripped or stripes - be able to identify striations - be able to identify skeletal muscle by its morphological characteristics This packet is about the histology of skeletal muscle. This packet will show you the morphological characteristics of skeletal muscle tissue that you need to know in order to identify it under a microscope. You will also learn about the basic functions of skeletal muscle in here as well.
1 Introduction Adult rodent skeletal muscles are composed of four types of myofibers (Bassel-Duby and Olson, 2006; Schiaffino and Reggiani, 1996; 2011), which are present in different proportions in different muscles. Slow-twitch (Type I) fibers have fatigue resistance properties by virtue of large numbers of mitochondria. The remaining three types are fast-twitch (Type II) fibers, subclassified as types IIA, IIX, and IIB. Of these, type IIA fibers exhibit the slowest shortening velocity and display fatigue resistance due to a high density of mitochondria. Conversely, type IIB fibers have the fastest shortening velocity and exhibit exercise intolerance due to a low density of mitochondria, while type IIX fibers are intermediate. Although the predominant fiber types in each muscle are determined during embryonic and fetal myogenesis (Agbulut et al., 2003; Lu et al., 1999), functional adaptations can lead to the alteration of these proportions through changes in gene expression (Oh et al., 2005; Swoap et
Most athletes stretch as part of their training regimen and it is commonly believed that this practice prevents muscle injury. We tested this belief using an animal model, in situ mouse extensor digitorum longus (EDL) muscle. One lower hindlimb was slowly stretched for 1 min on alternate days for 12 days; the other leg served as a control. The mouse was lightly anaesthetized during the stretching protocol (isofluorane). Both legs were tested in situ by measuring maximum isometric force and Show moreMost athletes stretch as part of their training regimen and it is commonly believed that this practice prevents muscle injury. We tested this belief using an animal model, in situ mouse extensor digitorum longus (EDL) muscle. One lower hindlimb was slowly stretched for 1 min on alternate days for 12 days; the other leg served as a control. The mouse was lightly anaesthetized during the stretching protocol (isofluorane). Both legs were tested in situ by measuring maximum isometric force and maximum ...
Definition of skeletal muscle cell in the Legal Dictionary - by Free online English dictionary and encyclopedia. What is skeletal muscle cell? Meaning of skeletal muscle cell as a legal term. What does skeletal muscle cell mean in law?
Schrauwen, P., Xia, J., Walder, K., Snitker, S. and Ravussin, E. 1999, A novel polymorphism in the proximal UCP3 promoter region: effect on skeletal muscle UCP3 mRNA expression and obesity in male non-diabetic Pima Indians, International journal of obesity, vol. 23, no. 12, pp. 1242-1245, doi: 10.1038/sj.ijo.0801057. ...
Skeletal muscle atrophy is thought to result from hyperactivation of intracellular protein degradation pathways including autophagy and the ubiquitin-proteasome system. actin (HSA) MLN2238 promoter (KO mice) and subjected them to denervation. The plantaris muscles a fast-twitch glycolytic skeletal muscle from both KO and control (KO mice showed resistance to denervation at 7 d after denervation (Fig.?1B-D; Fig. S2A). However the soleus muscles from KO mice and control mice exhibited comparable muscle mass and myofiber size at 14 d after denervation. Notably dead myofibers were frequently observed in the KO soleus muscles at 14 d (Fig.?1C). The enhanced cell death at 14 d most likely contributes to the shrinking of the soleus muscle of KO mice. The phenotypes of soleus muscles of KO mice at 14 d after denervation are coincident with the previous study.4 However the phenotypes at a period earlier than 14 d after denervation were not investigated in that study. Thus our finding seemed to reflect ...
OBJECTIVE Fat metabolism is increasingly implicated in the pathogenesis of type 2 diabetes. Endurance training has been shown to prevent hepatic steatosis and to alter skeletal muscle fat metabolism, and regional free fatty acid (FFA) uptake adaptations were suggested as a mechanism. Thus, we tested whether endurance training modifies the uptake of plasma FFAs occurring in the liver and in skeletal muscle during anabolic, i.e., hyperinsulinemic, conditions. RESEARCH DESIGN AND METHODS Trained and untrained healthy male subjects underwent positron emission tomography scanning of the liver and thigh regions, with the FFA analog 14(R,S)-[(18)F]fluoro-6-thia-heptadecanoic acid, during euglycemic hyperinsulinemia. Tracer influx rate constants in skeletal muscle (MK(i)) and liver (LK(i)) were multiplied by plasma FFA levels to obtain FFA uptake for skeletal muscle (MFU) and liver (LFU), respectively. RESULTS Athletes showed increased Vo(2max) (P | 0.0001), insulin-mediated glucose disposal (M value, 61 +/
Results. Coffee appears to induce autophagy, meaning that it upregulates the activity. This can prevent the accumulation of damaged protein and cellular components, optimizing function.. Two components of coffee, chlorogenic acid and caffeic acid appear to increase skeletal muscle glucose transport into the cell. It also increases sensitivity to insulin.. Finally, coffee intake attenuates the loss of muscle mass and strength that occurs with age. It also appears to increase the regenerative capacity of skeletal muscle in the aging adult.. Conclusions. Coffee appears to have multiple beneficial effects on skeletal muscle.. Regarding autophagy, coffee appears to help the body sweep up the damaged cellular products which can improve overall cellular activity.. It improves insulin sensitivity and glucose uptake, important not only for physical activity but for disease prevention.. Finally, it blunts the age-related skeletal muscle loss effects that occur naturally, known as sarcopenia, and may ...
Mitochondria play a key role in the energy metabolism in skeletal muscle. A new concept has emerged suggesting that impaired mitochondrial oxidative capacity in skeletal muscle may be the underlying defect that causes insulin resistance. According to current knowledge, the causes and the underlying molecular mechanisms at the origin of decreased mitochondrial oxidative capacity in skeletal muscle still remain to be elucidated. The present review focuses on recent data investigating these issues in the area of metabolic disorders and describes the potential causes, mechanisms and consequences of mitochondrial dysfunction in the skeletal muscle.
It is concluded that: Plasma leucine decreased and plasma and muscle ammonia increased following sprint exercise and more so in in males than females. Such changes might counteract a possible sprint exercise-induced stimulation of muscle protein synthesis. There was some activation of mTOR signalling in skeletal muscle following sprint exercise and more so in females than males. The larger increase in serum insulin and lower decrease in plasma leucine in females might have contributed to the enhanced signalling response in females. Oral ingestion of essential amino acids and carbohydrates, as compared to placebo, resulted in a markedly higher activation of Akt/mTOR signalling in skeletal muscle following sprint exercise. In contrast to the hypothesis, an oral ingestion of essential amino acids and carbohydrates did not result in an increased activation of hVps34 in skeletal muscle. However, this does not exclude the permissive role of hVps34 in mediating the amino acidinduced activation of ...
The endurance exercise-training program induced substantial improvements in peak exercise capacity and work capacity in the study population at 3 and 12 months of training compared with control patients. The hypothesis that older patients condition predominantly by noncardiac adaptations is supported by the fact that the increases in peak aerobic exercise capacity were mediated primarily by an increase in peak exercise AVo2 Diff with no measurable increase in peak exercise cardiac output. The increase in peak AVo2 Diff was associated with adaptations of skeletal muscle fiber size, capillarity, and SDH activity with only subtle alterations in cardiac performance and no discernible alterations of peripheral arterial blood flow. The skeletal muscle adaptations consisted of an increased oxidative enzyme activity and an increased capillary density after 3 months of conditioning and an increased muscle fiber cross-sectional area after 12 months of conditioning. However, although directional changes of ...
Muscles are a specialized body part that produces movement or locomotion in animals. The muscle is comprised (largely) of muscle tissues. A muscle tissue is made up of muscle cells, which in turn, consist of several myofibrils. The myofibril is the contractile thread of a muscle. Each myofibril is comprised of repeating sections of sarcomere. The sarcomere is composed of long fibrous proteins that slide past each other resulting in the appearance of dark and light bands under the microscope. The sarcomere is regarded as the basic structural unit of a muscle. Animal muscles are of three different types: (1) skeletal muscles, (2) smooth muscles, and (3) cardiac muscles. The skeletal muscles may be classified into fast twitch fibers and slow twitch fibers. The human body has approximately 650 skeletal muscles.1 The smooth muscles in turn may be subdivided into single-unit (unitary) smooth muscles and multiunit smooth muscles. The cardiac muscles are the muscles of the heart. These three types of ...
TY - JOUR. T1 - MicroRNA-23a has minimal effect on endurance exercise-induced adaptation of mouse skeletal muscle. AU - Wada, Shogo. AU - Kato, Yoshio. AU - Sawada, Shuji. AU - Aizawa, Katsuji. AU - Park, Jong Hoon. AU - Russell, Aaron P.. AU - Ushida, Takashi. AU - Akimoto, Takayuki. PY - 2014. Y1 - 2014. N2 - Skeletal muscles contain several subtypes of myofibers that differ in contractile and metabolic properties. Transcriptional control of fiber-type specification and adaptation has been intensively investigated over the past several decades. Recently, microRNA (miRNA)-mediated posttranscriptional gene regulation has attracted increasing attention. MiR-23a targets key molecules regulating contractile and metabolic properties of skeletal muscle, such as myosin heavy-chains and peroxisome proliferator-activated receptor gamma, coactivator 1 alpha (PGC-1α). In the present study, we analyzed the skeletal muscle phenotype of miR-23a transgenic (miR-23a Tg) mice to explore whether forced ...
Skeletal Muscle Diagram - See more about Skeletal Muscle Diagram, skeletal muscle diagram, skeletal muscle diagram labeled, skeletal muscle diagram quiz, skeletal muscle diagram worksheet
Skeletal muscle constitutes a large part of the human body. It is a hierarchically organized heterogeneous tissue and is composed of muscle fiber bundles, muscle fibers, myofibrils and myofilaments. Since muscle cells are terminally differentiated, they have limited capacity to renew themselves. Only new cells can fuse with muscle fibers and increase the size and volume of skeletal muscle. Myosatellite cells or satellite cells are small, mononuclear progenitor cells with virtually no cytoplasm. They are located in between the sarcolemma and basement membrane of terminally-differentiated muscle fibers. Satellite cells are precursors to skeletal muscle cells, and are able to give rise to satellite cells or differentiated skeletal muscle cells. They are normally found in silent state in adult muscle, but act as a reserve cell population that is able to proliferate in response to injury and give rise to regenerated muscle and to more satellite cells. Formation of the new muscular tissue is called ...
INTRODUCTION The injury caused by reperfusion of ischemic skeletal muscle is mediated by the membrane attack complex of complement (C) . This C activation results from local classical pathway activation after deposition of IgM in injured muscle, an event analogous to C deposition in the mucosa of the gut during reperfusion . Our past analysis has indicated that the injury is not uniform even within a single microscopic section. This study was performed to elucidate the exact site of IgM and C deposition on muscle injured by ischemia and reperfusion. MATERIALS AND METHODS C57Bl/6 mice were subjected to 2 h of tourniquet-induced hindlimb ischemia followed by reperfusion for 0-6 h. Three muscle groups (vastus, gastrocnemius, and soleus) of varying fast-myosin content were compared for muscle fiber damage and C deposition. Adjacent paraffin-embedded cross-sections were immunostained to correlate C3 deposition with muscle fiber type as defined by monoclonal antibodies. RESULTS Muscle injury after
The aims of this study were to investigate the mechanisms underlying (1) the ageing-related motor handicap at the whole muscle, cellular, contractile protein and myonuclear levels; and (2) ageing-related differences in muscle adaptability.. In vivo muscles function was studied in the knee extensors. Decreases were observed in isokinetic and isometric torque outputs in old age in the sedentary men and women and elite master sprinters. A 20-week long specific sprint and resistance training successfully improved the maximal isometric force and rate of force development in a subgroup of master sprinters.. In vitro measurements were performed in muscle biopsies from the vastus lateralis muscle. Immunocytochemical and contractile measurements in single membrane permeabilized muscle fibres demonstrated ageing- and gender-related changes at the myofibrillar level. In sedentary subjects, data showed a preferential decrease in the size of muscle fibres expressing type IIa MyHC in men, lower force ...
AS160 is an Akt substrate of 160 kDa implicated in the regulation of both insulin- and contraction-mediated GLUT4 translocation and glucose uptake. The effects of aerobic exercise and subsequent insulin stimulation on AS160 phosphorylation and the binding capacity of 14-3-3, a novel protein involved in the dissociation of AS160 from GLUT4 vesicles, in human skeletal muscle are unknown. Hyperinsulinemic-euglycemic clamps were performed on seven men at rest and immediately and 3 h after a single bout of cycling exercise. Skeletal muscle biopsies were taken before and after the clamps. The insulin sensitivity index calculated during the final 30 min of the clamp was 8.0 ± 0.8, 9.1 ± 0.5, and 9.2 ± 0.8 for the rest, postexercise, and 3-h postexercise trials, respectively. AS160 phosphorylation increased immediately after exercise and remained elevated 3 h after exercise. In contrast, the 14-3-3 binding capacity of AS160 and phosphorylation of Akt and AMP-activated protein kinase were only ...
Muscle wasting is a severe complication of critical illness [1]. Puthucheary et al. reported a steady decrease in skeletal muscle mass of almost 20% during the first 10 days of intensive care unit (ICU) admission [2]. Loss of muscle has been associated with longer duration of mechanical ventilation and higher ICU and hospital mortality [3-5]. If patients survive, they exhibit long-term functional disability with a great impact on quality of life for as long as 5 to 8 years after admission [6-8]. However, many patients already have a low muscle quantity upon admission to the ICU. In two retrospective studies as much as 60-70% of patients had low muscle quantity as assessed on computed tomography (CT) scans on ICU admission, and low muscle quantity at ICU admission was associated with a higher mortality [9, 10].. Not only the quantity, but also the quality of muscle seems important [11]. Along with a decline in muscle mass, fatty infiltration of muscles or myosteatosis has been identified as a ...
Skeletal muscle weakness can delay the discontinuation of mechanical ventilation and, even in patients who survive, persists for years after hospital discharge impairing quality of life. Older patients with IAV infection have higher rates of respiratory distress and are at increased risk for developing skeletal muscle dysfunction. An expanding body of literature reports that skeletal muscle dysfunction develops very soon after the onset of critical illness, suggesting it is triggered by an active signaling process. In preliminary experiments, we found that aged mice develop more severe and prolonged skeletal muscle dysfunction during IAV infection. Proteostasis is at the center of protein function and encompasses all cellular processes that regulate protein folding, misfolding, unfolding, degradation and repair. Our studies suggest that endocrine signals from the injured lung during IAV infection can disrupt skeletal muscle proteostasis pathways and contribute to skeletal muscle dysfunction. We ...
Local and systemic skeletal muscle degeneration is a common consequence of envenomations due to snakebites and mass bee attacks. Phospholipases A2 (PLA2) are important myotoxic components in these venoms, inducing a similar pattern of degenerative events in muscle cells. Myotoxic PLA2s bind to acceptors in the plasma membrane, which might be lipids or proteins and which may differ in their affinity for the PLA2s. Upon binding, myotoxic PLA2s disrupt the integrity of the plasma membrane by catalytically dependent or independent mechanisms, provoking a pronounced Ca2+ influx which, in turn, initiates a complex series of degenerative events associated with hypercontraction, activation of calpains and cytosolic Ca2+-dependent PLA2s, and mitochondrial Ca2+ overload. Cell culture models of cytotoxicity indicate that some myotoxic PLA2s affect differentiated myotubes in a rather selective fashion, whereas others display a broad cytolytic effect. A model is presented to explain the difference between ...
An important pending question in neuromuscular biology is how skeletal muscle cells decipher the stimulation pattern coming from motoneurons to define their phenotype as slow or fast twitch muscle fibers. We have previously shown that Cav1.1 acts as a voltage sensor for activation of IP3-dependent Ca2+ signals that regulate gene expression. ATP released by muscle cells after electrical stimulation via pannexin-1 channels plays a key role in this process.. We show now, that stimulation frequency determines both ATP release and IP3 production in adult skeletal muscle and that Cav1.1 and pannexin-1 co-localize in the transverse tubules. Both ATP release and increased IP3 was seen in FDB fibers stimulated with 270 pulses at 20 Hz, but not at 90 Hz. 20 Hz stimulation induces transcriptional changes related to fast-to-slow muscle fiber phenotype transition that required ATP release. Addition of 30 µM ATP to FDB fibers induces the same transcriptional changes observed after 20 Hz stimulation. Myotubes ...
TY - JOUR. T1 - Myogenic, matrix and growth factor mRNA expression in human skeletal muscle: effect of contraction intensity and feeding. AU - Agergaard, Jakob. AU - Reitelseder, Søren. AU - Pedersen, T.G.. AU - Doessing, Simon. AU - Schjerling, Peter. AU - Langberg, Henning. AU - Miller, Benjamin F. AU - Aagaard, P. AU - Kjær, Michael. AU - Holm, Lars. PY - 2013/3/20. Y1 - 2013/3/20. N2 - INTRODUCTION: We examined short-term (3-hour) and long-term (12-week) training effects after heavy load [HL; 70% 1RM] and light load (LL; 16% 1RM) exercise. METHODS: mRNA expression of genes involved in skeletal muscle remodeling were analyzed and muscle activity (EMG measurements) was measured. RESULTS: Relative muscle activity differed between HL and LL resistance exercise, whereas median power frequency was even, suggesting an equal muscle-fiber-type recruitment distribution. mRNA expression of Myf6, myogenin, and p21 was mostly increased, and myostatin was mostly depressed by HL resistance exercise. No ...
Skeletal Muscle Cell Diagram - See more about Skeletal Muscle Cell Diagram, skeletal muscle cell diagram, skeletal muscle cell picture
TY - JOUR. T1 - Reduced short- and long-latency afferent inhibition following acute muscle pain. T2 - A potential role in the recovery of motor output. AU - Burns, Emma. AU - Chipchase, Lucinda Sian. AU - Schabrun, Siobhan May. N1 - © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: [email protected] PY - 2016/7/1. Y1 - 2016/7/1. N2 - OBJECTIVE: . Corticomotor output is reduced in response to acute muscle pain, yet the mechanisms that underpin this effect remain unclear. Here the authors investigate the effect of acute muscle pain on short-latency afferent inhibition, long-latency afferent inhibition, and long-interval intra-cortical inhibition to determine whether these mechanisms could plausibly contribute to reduced motor output in pain.DESIGN: . Observational same subject pre-post test design.SETTING: . Neurophysiology research laboratory.SUBJECTS: . Healthy, right-handed human volunteers (n = 22, 9 male; mean age ± standard ...
Context/Objective: The aim of this study was to evaluate the regulation of the fuel partitioning and energy metabolism in skeletal muscle during lipid overfeeding in healthy men. Design/Participants/Intervention: Thirty-nine healthy volunteers were overfed for 56 days with a high-fat diet (3180 kJ/d). Energy metabolism (indirect calorimetry) was characterized in the fasting state and during a test meal before and at the end of the diet. Skeletal muscle biopsies were taken at day 0 and day 56. Main Outcome Measures: Change in gene expression, mitochondrial respiration, nicotinamide adenine dinucleotide (NAD(+)) content, and acetylation of peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1 alpha) in skeletal muscle was measured. Results: Overfeeding increased body weight (+2.6 kg) and fat mass concomitantly with a shift in the use of substrates as energy fuel toward preferential oxidation of carbohydrates instead of lipids. Changes in lipid metabolic gene expression supported this
Insulin is an important anabolic hormone. Its signaling through Akt promotes maintenance or increases in muscle mass by activating mTOR, the classic master-regulator of protein synthesis and by decreasing proteolysis. High-fat diet-induced obesity impairs insulin-sensitivity and decreases insulin-stimulated mTOR signaling to its target p70S6k. AMP-activated protein kinase (AMPK) blocks mTOR activity, protein synthesis and muscle growth, and AMPK is activated by high-fat diet feeding, suggesting that it may play a role in high-fat diet-induced resistance of mTOR to insulin stimulation. Therefore, we hypothesized that a loss of AMPK activity through the loss of skeletal muscle LKB1 (the primary AMPK activator in skeletal muscle), would prevent the attenuation of insulin-induced mTOR signaling with high-fat diet-induced obesity. To test this, skeletal muscle specific LKB1 knockout (KO) and wild-type littermate (WT) mice were fed a standard chow diet (SD) or a high-fat diet (HFD) for 14 weeks. ...
In skeletal muscle, an accumulation of lipid droplets (LDs) in the subsarcolemmal space is associated with insulin resistance, but the underlying mechanism is not clear. We aimed to investigate how the size, number and location of LDs are associated with insulin sensitivity and muscle fiber types, and are regulated by aerobic training and treatment with an erythropoiesis-stimulating agent (ESA) in healthy young untrained males. LD analyses were performed by quantitative transmission electron microscopy and insulin sensitivity was assessed by a hyperinsulinemic euglycemic clamp. At baseline, we found that only the diameter (and not the number) of individual subsarcolemmal LDs was negatively associated with insulin sensitivity (R2 = 0.20, P = 0.03, n = 29). Despite 34% (P = 0.004) fewer LDs, the diameter of individual subsarcolemmal LDs was 20% (P = 0.0004) larger in type 2 fibers than in type 1 fibers. Furthermore, aerobic training decreased the size of subsarcolemmal LDs in the type 2fibers, and ...
In skeletal muscle, an accumulation of lipid droplets (LDs) in the subsarcolemmal space is associated with insulin resistance, but the underlying mechanism is not clear. We aimed to investigate how the size, number and location of LDs are associated with insulin sensitivity and muscle fiber types, and are regulated by aerobic training and treatment with an erythropoiesis-stimulating agent (ESA) in healthy young untrained males. LD analyses were performed by quantitative transmission electron microscopy and insulin sensitivity was assessed by a hyperinsulinemic euglycemic clamp. At baseline, we found that only the diameter (and not the number) of individual subsarcolemmal LDs was negatively associated with insulin sensitivity (R2 = 0.20, P = 0.03, n = 29). Despite 34% (P = 0.004) fewer LDs, the diameter of individual subsarcolemmal LDs was 20% (P = 0.0004) larger in type 2 fibers than in type 1 fibers. Furthermore, aerobic training decreased the size of subsarcolemmal LDs in the type 2fibers, and ...
Impaired locomotor performance is caused by complex, multi-faceted problems where changes in the nervous, muscular, and skeletal systems are all integrated and dependent on one another in a way that makes diagnosis and interventions difficult to access and implement. Specifically, muscle properties such as musculoskeletal architecture (e.g. muscle fascicle length, pennation angle, muscle thickness, and moment arm), fiber composition, and material properties, as well as motor unit recruitment ha...[Read full text]Impaired locomotor performance is caused by complex, multi-faceted problems where changes in the nervous, muscular, and skeletal systems are all integrated and dependent on one another in a way that makes diagnosis and interventions difficult to access and implement. Specifically, muscle properties such as musculoskeletal architecture (e.g. muscle fascicle length, pennation angle, muscle thickness, and moment arm), fiber composition, and material properties, as well as motor unit ...
Objective. Common variants in FTO (the fat-mass and obesity-associated gene) associate with obesity and type 2 diabetes. The regulation and biological function of FTO mRNA expression in target tissue is unknown. We investigated the genetic and non-genetic regulation of FTO mRNA in skeletal muscle and adipose tissue, and their influence on in vivo glucose and fat metabolism. Research Design and Methods. The FTO rs9939609 polymorphism was genotyped in two twin cohorts: 1) 298 elderly twins aged 62-83 years with glucose tolerance ranging from normal to type 2 diabetes and 2) 196 young (25-32 years) and elderly (58-66 years) non-diabetic twins examined by a hyperinsulinemic euglycemic clamp including indirect calorimetry. FTO mRNA expression was determined in subcutaneous adipose tissue (n=226) and skeletal muscle biopsies (n=158). Results. Heritability of FTO expression in both tissues was low, and FTO expression was not influenced by FTO rs9939609 genotype. FTO mRNA expression in skeletal muscle ...
Taken together, our results of maintained oxidative capacity in CHF require three considerations. First, the fact that the concentration or activity of several enzymes of the Krebs cycle and of certain electron transport chain complexes like the cytochrome oxidase (21)have been found lowered in skeletal muscle from patients with CHF does not imply a decreased overall oxidative function since mitochondria are functioning well above their limitation threshold for most of their enzymatic complexes (22), in line with the cytochrome oxidase excess already largely documented (23). A limitation at the level of the Krebs cycle is an unlikely explanation despite the decrease in CS we and others found (6,24)because neither CS nor the Krebs cycle are rate-controlling mitochondrial respiration (22,25). Indeed, numerous extra-mitochondrial reasons also explain the high-energy phosphate abnormalities in CHF. High-energy phosphate abnormalities observed in CHF skeletal muscle may result from intrinsic or ...
Previous studies have shown that diabetes adversely affects breathing and respiratory functions. However, in the past, researchers have not differentiated diaphragm muscle cells and the muscle cells of limb skeletal muscle in their studies. Now, researchers from the University of Missouri have found that diaphragm muscle cells and other skeletal muscle cells behave differently - a finding that could influence future research on respiratory ailments associated with diabetes.
Exercise increases the strength of skeletal muscles by enlarging the cells and changing the interaction between nerves and muscles, according to Scientific American. Muscle cells that undergo regular...
The expression of receptors and the mitogenic response to PDGF by C2 myoblasts, derived from adult mouse skeletal muscle, was investigated. Employing 125I-PDGF binding assays, we showed that the cells exhibit high level binding of PDGF-BB (approximately 165 x 10(3) molecules/cell at saturation) and much lower binding of the PDGF-AA and PDGF-AB (6-12 x 10(3) molecules/cell at saturation). This indicates that the C2 myoblasts express high levels of PDGF receptor beta-subunits and low levels of alpha-subunits. PDGF-BB enhances the proliferation of C2 cells maintained in 2% FCS by about fivefold. PDGF-AB had a moderate effect on cell proliferation (less than twofold) and PDGF-AA had no effect. Inverse effects of PDGF isoforms on the frequency of differentiated myoblasts were observed; the frequency of myosin-positive cells was reduced in the presence of PDGF-BB while PDGF-AA and PDGF-AB had no effect. PDGF may thus act to increase the number of myoblasts that participate in muscle regeneration ...
Figure 2: Histopathology related to injury. (a) cross-section of normal healthy TA muscle from a wild-type mouse. Skeletal muscle fibers are multinucleated and the nuclei stain blue; the sarcoplasm of each cell stains pink. (b) cross-section from a wild-type TA after injury. There was only minimal evidence of perivascular inflammation (arrows) in the wild-type tissue after injury. (c) cross-section from TA muscle of an mdx mouse. Even without injury, there is mild inflammation, slight increase in endomysial connective tissue, heterogeneity in fiber size, and many centrally nucleated fibers (CNFs, open arrows), all indicative of ongoing degeneration/regeneration within the muscle. (d) cross-section from an mdx TA after injury. Even with a protocol that produces mild changes in morphology to healthy muscle, the mdx muscle suffers much more damage, such as myonecrosis, myophagocytosis, and foci of inflammation surrounding individual muscle fibers (closed arrows). Scale bar = 40 μm ...
Although high-throughput studies of gene expression have generated large amounts of data, most of which is freely available in public archives, the use of this valuable resource is limited by computational complications and non-homogenous annotation. To address these issues, we have performed a complete re-annotation of public microarray data from human skeletal muscle biopsies and constructed a muscle expression compendium consisting of nearly 3000 samples. The created muscle compendium is a publicly available resource including all curated annotation. Using this data set, we aimed to elucidate the molecular mechanism of muscle aging and to describe how physical exercise may alleviate negative physiological effects ...
The lesson looks in-depth at the structure and function of skeletal, cardiac and smooth muscle. It explains how the muscles work.
The ability of a muscle to shorten and produce force is crucial for locomotion, posture, balance and respiration. During a contraction, myosin heads on the myosin filament propel the actin filament via ATP hydrolysis, resulting in shortening of the muscle and/or force generation. The maximal shortening velocity of a muscle fibre is largely determined by the myosin ATPase activity, while maximal force is primarily determined by the cross-sectional area. Since most muscles are pennate rather than parallel-fibred and work at different lever ratios, muscle architecture and joint-tendon anatomy has to be taken into account to obtain the force and velocity characteristics of a muscle. Additionally, the recruitment of agonistic and antagonistic muscles will contribute to the torque generated during a contraction. Finally, tendon compliance may impact on the rate of force rise and force generated if it is such that the muscle contraction proceeds in the ascending limb of the length-tension relation. ...
Abstract. Skeletal muscle fibre types are determined by the activity of motor neurons, hormones, stretch and probably cell lineage. The electrical activity of the motor neurons might, through an unknown pathway, influence the expression of a unique set of muscle specific genes in the different fibre types.. MRF4 is a member of a family of myogenic basic helix-loop-helix transcription factors (bHLH) that is important for the development of muscle fibres. These transcription factors are also suggested to be important in adult muscle, where they might be a possible link between electrical activity and expression of muscle specific genes. The myogenic bHLH transcription factors MyoD and myogenin has been shown to possible be involved in the regulation of fibre type specificity. This role is also proposed for MRF4, based on the high amount of MRF4 mRNA that is expressed in all adult skeletal muscle types and that it seems to be preferentially expressed in slow fibre types.. In this thesis I wanted to ...
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AppliedStemCell eCommerce Platform Human Skeletal Muscle Cells cDNA (DMD) [ASD-9042] - Catalog Number ASD-9042 Quantity 20 reactions Product Information Description Applied StemCells cDNA is synthesized from a highly pure and intact total RN
Looking for Skeletal muscles? Find out information about Skeletal muscles. A striated, voluntary muscle attached to a bone and concerned with body movements Explanation of Skeletal muscles
A Serine/Threonine kinase, mTOR, is a cellular target of rapamycin and plays a role in cellular growth and proliferation by regulating translation through the phosphorylation of 4E-BP1 and S6K. Here, I investigated the function of mTOR for the activation of newly found S6K1 homologue, S6K2, and for the regulation of skeletal muscle myotube growth. My results showed that S6K2 requires mTOR and its kinase activity for its activation. Amino acid and nuclear-cytoplasmic shuttling of mTOR were shown to be required for S6K2 activation. Skeletal myogenesis is a well-coordinated process composed of the determination of myogenic lineage of somitic stem cell, cell cycle withdrawal, the expression of myogenic specific genes and the fusion of myoblasts to form multinucleated myotubes. Skeletal myofibers also undergo hypertrophy with work overload, characterized by size increase and biochemical changes. I showed that the IGF-I-mediated skeletal muscle hypertrophy requires mTOR and its kinase activity, as ...
Skeletal muscle is able to respond to a range of stimuli, including stretch and increased load, by increasing in diameter and length in the absence of myofiber division. This type of cellular growth (hypertrophy) is a highly complex process involving division of muscle precursor cells (myoblasts) and their fusion to existing muscle fibers as well as increased protein synthesis and decreased protein degradation. Underlying the alterations in protein levels are increases in a range of specific mRNAs including those coding for structural proteins and proteins that regulate the hypertrophic process. Seven days of passive stretch in vivo of tibialis anterior (TA) muscle has been shown to elicit muscle hypertrophy. We have identified a cDNA corresponding to an mRNA that exhibits increased expression in response to 7 days of passive stretch imposed on TA muscles in vivo. This 944-bp novel murine transcript is expressed primarily in cardiac and skeletal muscle and to a lesser extent in brain. ...
Around 30% of women and 15% of men in the United States over 60 years self-report that they are unable to lift or carry 10 pounds, and ~ 50% of women and 40% of men report difficulty in stooping, crouching, or kneeling [1]. Further, more than 40% of seniors have limitations in performing one or more daily tasks (e.g., walking two to three blocks, transferring from sitting to standing) that are essential for maintaining physical independence [1]. While many factors contribute to reductions in physical function, one contributor is skeletal muscle impairments (e.g., muscle weakness) [2]. While the nervous system is widely recognized for its role in coordination, its role in determining the performance characteristics of aged skeletal muscle has largely been understudied. Historically, it was believed that the reductions in muscle performance were primarily resultant of age-associated adaptations in skeletal muscle (e.g., muscle atrophy). However, the vast range of motions and forces that humans can achieve
The decline in functional performance and restriction of adaptability represents the hallmark of skeletal muscle pathologies. The characteristic loss in muscle mass, coupled with a decrease in strength and force output, has been associated with a selective activation of apoptotic pathways and a general reduction in survival mechanisms. Aging and genetic diseases, such as muscular dystrophies, amyotrophic lateral sclerosis, cancer and AIDS, are characterized by alterations in metabolic and physiological parameters, progressive weakness in specific muscle groups, modulation in muscle-specific transcriptional mechanisms and persistent protein degradation. The inability to regenerate and repair the injured muscle is another serious complication in muscle pathologies. Tissue remodeling is therefore an important physiological process, which allows skeletal muscle to respond to environmental demands and to undergo adaptive changes in cytoarchitecture and protein composition, in response to a variety of stimuli
TY - JOUR. T1 - Effects of forward trunk lean on hamstring muscle kinematics during sprinting. AU - Higashihara, Ayako. AU - Nagano, Yasuharu. AU - Takahashi, Kazumasa. AU - Fukubayashi, Toru. PY - 2015/8/9. Y1 - 2015/8/9. N2 - Abstract: This study aimed to investigate the effects of forward trunk lean on hamstring muscle kinematics during sprinting. Eight male sprinters performed maximal-effort sprints in two trunk positions: forward lean and upright. A three-dimensional musculoskeletal model was used to compute the musculotendon lengths and velocity of the biceps femoris long head, semitendinosus, and semimembranosus muscles during the sprinting gait cycle. The musculotendon lengths of all the three hamstring muscles at foot strike and toe-off were significantly greater during the forward trunk lean sprint than during the upright trunk sprint. In addition, a positive peak musculotendon lengthening velocity was observed in the biceps femoris long head and semimembranosus muscles during the late ...
While performing a unilateral muscle contraction, electrical muscle activity also arises in the contralateral homologous muscle, muscle group, or limb. When the muscle contraction induces muscle fatigue, females show not only a greater resistance than males but also a reduced contralateral muscle activation. The study aimed at investigating whether, during a high-intensity 30-s unilateral maximal effort isometric leg extension exercise, the contralateral non-exercising limb (NEL) knee extensor muscle activation would differ between females and males. Twenty participants, 11 females (23.80 ± 2.15 years old) and 9 males (26.50 ± 2.45 years old), performed a unilateral 30-s exercise while surface electromyography (sEMG) was measured from the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF) on both limbs. The maximal voluntary contraction (MVC) was measured for both the exercising limb (EL) and the NEL before (MVC PRE) and after (MVC POST) the 30-s exercise to assess muscle fatigue.
The purpose of this study was to determine whether certain chemokines, which are highly expressed in injured skeletal muscle, are involved in the repair and functional recovery of the muscle after traumatic injury. In wild-type control mice, mRNA transcripts of macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and monocyte chemoattractant protein (MCP)-1 as well as their major receptors, CC
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Aging is associated with decreased muscle mass and functional capacity, which in turn decrease quality of life. The number of citizens over the age of 65 years in the Western world will increase by 50 % over the next four decades, and this demographic shift brings forth new challenges at both societal and individual levels. Only a few longitudinal studies have been reported, but whey protein supplementation seems to improve muscle mass and function, and its combination with heavy strength training appears even more effective. However, heavy resistance training may reduce adherence to training, thereby attenuating the overall benefits of training. We hypothesize that light load resistance training is more efficient when both adherence and physical improvement are considered longitudinally. We launched the interdisciplinary project on Counteracting Age-related Loss of Skeletal Muscle Mass (CALM) to investigate the impact of lifestyle changes on physical and functional outcomes as well as everyday ...
maropice.com Page 19: Lovely Muscles In Arm Beautiful Skeletal Muscle Tissue Beautiful Cardiac Anatomy Inspirational Brain Physiology Luxury where is Prostate Located muscles of arm ppt muscles in arm contracting muscles of arm ppt muscles in arm and hand muscles in arm abduction - Human Anatomy
Fast-twitch skeletal muscles are specialized for in vivo motor functions that require high power (mastication and load lifting), high speed (eyelid blink), or a combination of the two (withdrawal reflexes and escape responses). Those functions that rely on high power often involve tetanic stimulation of the effector muscles, resulting in sustained force generation even during tetani that are not fused, which is the physiological norm (McMahon, 1984; Biewener, 2016). Taking escape responses as an example, there is a clear adaptive advantage to rapid initiation of a forceful ballistic contraction, which to a degree is achieved by expression of skeletal muscle myosin isoforms that exhibit fast or super-fast turnover rates in their interactions with actin (Rome and Lindstedt, 1998; Hoh, 2002). Rapid delivery of Ca2+ to the myoplasm during excitation-contraction coupling is another mechanism that would presumably speed the rate of force development and contribute to an early increase in the ability ...
Following laparotomy and retroperitoneal dissection, dogs increase skeletal muscle proteolysis and excrete increased quantities of nitrogen in the urine. Pretreatment with a cyclo-oxygenase inhibitor (Ibuprofen) diminished this response in the 5 animals studied to date. More animals are required to make firm conclusions as to the effectiveness of this therapy on post traumatic metabolism.*HYDROLYSIS
Mitochondrial function in human skeletal muscle declines with age. Most evidence for this decline comes from studies that assessed mitochondrial function indirectly, and the impact of such deterioration with respect to physical function has not been clearly delineated. We hypothesized that mitochondrial respiration in permeabilized human muscle fibers declines with age and correlates with phosphocreatine postexercise recovery rate (kPCr), muscle performance, and aerobic fitness. Mitochondrial respiration was assessed by high-resolution respirometry in saponin-permeabilized fibers from vastus lateralis muscle biopsies of 38 participants from the Baltimore Longitudinal Study of Aging (BLSA; 21 men, age 24-91 years) who also had available measures of peak oxygen consumption (VO2max ) from treadmill tests, gait speed in different tasks, 31 P magnetic resonance spectroscopy, isokinetic knee extension, and grip strength ...
Skeletal muscle: Skeletal muscle, in vertebrates, most common of the three types of muscle in the body. Skeletal muscles are attached to bones by tendons, and they produce all the movements
In this study of randomly selected older individuals, persons with diabetes had slower gait speed and, despite having a larger muscle calf area, had lower muscle strength, muscle power, and muscle quality than persons without diabetes. In multivariable analyses adjusted for muscle density, muscle strength, muscle power, and muscle quality, the difference in gait speed between persons with and without diabetes was attenuated up to 25 and 15% in the 4- and 400-m tests, respectively, suggesting that impaired lower-limb skeletal muscle performance is an important contributor to mobility limitation in older patients with type 2 diabetes.. Our findings extend the results of previous studies, providing new insight into the complex and multifactorial biological pathways linking diabetes and walking impairment in older persons. Type 2 diabetes has been associated with muscle atrophy and weakness in different clinical (26) and population-based samples (10), and diabetic neuropathy involving motor neurons ...
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
Macrophage PPARγ is required for normal skeletal muscle and hepatic insulin sensitivity and full antidiabetic effects of thiazolidinediones: PPARγ is required f
The muscular system can be broken down into three types of muscles: skeletal, smooth and cardiac. Skeletal muscles are the only voluntary muscle tissue in the human body and control every action that a person consciously performs. As the muscular system impacts so many of the functions necessary to sustain life, any muscle disorder can cause health problems, ranging from minor to severe. Not only do muscular disorders affect mobility, but can result in many other functional abnormalities, such as the inability to breath, swallow or speak. Causes of muscle disorders include injury or overuse, such as sprains or strains, cramps or tendinitis, a genetic disorder, such as muscular dystrophy, cancers, inflammation, such as myositis, diseases of nerves that affect muscles, infections, and certain medicines. Calf muscle - The calf muscle, on the back of the lower leg, is actually made up of two muscles: the gastrocnemius and the soleus. The gastrocnemius is the larger calf muscle, forming the bulge ...
Skeletal muscle adaptation to fatty acid depends on coordinated actions of the PPARs and PGC1 alpha: implications for metabolic disease.
Regulation Of Lipid Utilisation In Skeletal Muscle During Exercise In Humans bog: Titel: Regulation Of Lipid Utilisation In Skeletal Muscle During Exerc...
Principle objective of this lecture is to presentation on Skeletal Muscle Tissue. Here Summarize the distinguishing characteristics of the different muscle
During passive lower limb movement, active use of the upper limbs increases unintentional lower limb muscle activation. We hypothesized that faster movement frequencies would amplify lower limb muscle activation during upper limb exertion but would not affect lower limb muscle activation when the upper limbs were relaxed. We studied 10 healthy participants exercising on a recumbent stepping machine that mechanically coupled the four limbs via handles and pedals. Participants exercised at four frequencies (30, 60, 90, 120 steps/min) under four conditions of active and passive movement. Self-driven lower limb motion resulted in greater muscle activation compared to externally driven lower limb motion. Muscle activation amplitude increased with frequency for all conditions except for externally driven stepping. These results indicate that fast upper limb movement facilitates neuromuscular recruitment of lower limb muscles during stepping tasks. If a similar effect occurs in neurologically impaired ...
Resistance exercise (RE) can improve the overall quality of life and reduce the symptoms of many clinical disorders, including obesity, type II diabetes mellitus [1], coronary heart disease, and stroke [2]. The effects of RE on skeletal muscle are mediated by activation of muscle-specific signaling cascades that increase muscle mass [3], cytoskeletal protein levels, and the force of contraction without increasing the number of myofibers [4]. Exercise-induced transcription of genes involved in growth, vascularization, and metabolism [5-8] indicates that large-scale changes in transcriptional regulation play a key role in muscle remodeling, inducing growth responses and metabolic shifts.. Exercise also appears to help reset circadian rhythms in shift-workers, travelers who have changed time zones, and people with sleep disorders [9-13]. Circadian rhythms are approximately 24-hour fluctuations in gene regulation, physiology, and behavior that have evolved to optimize daily cycles of sleep, ...
Video articles in JoVE about muscular dystrophies include Isometric and Eccentric Force Generation Assessment of Skeletal Muscles Isolated from Murine Models of Muscular Dystrophies, Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease, Analysis of Zebrafish Larvae Skeletal Muscle Integrity with Evans Blue Dye, Transplantation of Induced Pluripotent Stem Cell-derived Mesoangioblast-like Myogenic Progenitors in Mouse Models of Muscle Regeneration, In Situ Immunofluorescent Staining of Autophagy in Muscle Stem Cells, In Vivo Modeling of the Morbid Human Genome using Danio rerio, Analysis of Skeletal Muscle Defects in Larval Zebrafish by Birefringence and Touch-evoke Escape Response Assays, Isolation and Immortalization of Patient-derived Cell Lines from Muscle Biopsy for Disease Modeling, Dos and Donts in the Preparation of Muscle Cryosections for Histological Analysis, Analysis of Embryonic and Larval Zebrafish Skeletal Myofibers from Dissociated Preparations,
Maréchal, Georges ; Beckersbleukx, G.. [Effects of nitric oxide on force-velocity relationship of striated skeletal musculature of the mouse].64th Conference of the Societe-de-Physiologie (LILLE(France), Sep 18-20, 1996). In: Archives of Physiology and Biochemistry : the journal of metabolic diseases, Vol. 104, no. 4, p. D72 (1996 ...
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
Because of conflicting expert opinions, there are either 639 or 640 skeletal muscles in the human body depending on who you ask. The definition of what constitutes a distinct muscle is still up for debate.References:Drstandley: Muscular System, Number of Muscles in the Human Body, Types of Muscle
Skeletal muscle mass is regulated by a complex array of signaling pathways. TGF-β-activated kinase 1 (TAK1) is an important signaling protein, which regulates context-dependent activation of multiple intracellular pathways. However, the role of TAK1 in the regulation of skeletal muscle mass remains unknown. Here, we report that inducible inactivation of TAK1 causes severe muscle wasting, leading to kyphosis, in both young and adult mice.. Inactivation of TAK1 inhibits protein synthesis and induces proteolysis, potentially through upregulating the activity of the ubiquitin-proteasome system and autophagy. Phosphorylation and enzymatic activity of AMPK are increased, whereas levels of phosphorylated mTOR and p38 MAPK are diminished upon inducible inactivation of TAK1 in skeletal muscle. In addition, targeted inactivation of TAK1 leads to the accumulation of dysfunctional mitochondria and oxidative stress in skeletal muscle of adult mice. Inhibition of TAK1 does not attenuate denervation-induced ...
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Immunochemical analysis of C protein isoform transitions during the development of chicken skeletal muscle is an eagle-i resource of type Journal article at eagle-i Network Shared Resource Repository.
It is traditionally assumed that intensities of more than 60% of one-repetition maximum (1 RM) are required for significant muscle growth (hypertrophy) (Schoenfeld, 2013). Fry, in his well-known work of 2004, goes a step further. Even though he gives a range of 40-95% of 1RM for hypertrophy training, he emphasizes the range of 80-85% of 1 RM as optimal hypertrophy (Fry, 2004).. The classic argument considers the mechanical stress and subsequent exhaustion of muscle fibers as being primarily responsible for muscle growth. Furthermore, it is assumed that the muscle fibers are recruited according to the principle of size, e.g. as the load increases, stronger units are being addressed. Under the above-mentioned intensity, the largest motor units (type II muscle fibers) are not activated and thus cannot (optimally) be trained. However, according to research, these fibers have a 50% higher growth potential and are thus indispensable for optimal muscle or strength building (Schoenfeld, ...
The Skeletal Muscles There are about 650 muscles in the human body The Skeletal Muscles There are about 650 muscles in the human body. They enable us to move, maintain posture and generate heat. In this section we will only study a sample of the major muscles. There are about 650 muscles in the human body. They enable us to move, maintain posture and generate heat. In this unit will only study a sample of the major muscles.
... Barnes B.R., T.C. Selix, D.C. Wright, and B.W. Craig. Ball State University, Muncie, IN.The purpose of this investigation was to determine the effects of a glucocorticoid-antagonist (RU486) on insulin-like-growth-factor-1 (IGF1)stimulated glucose transport following two weeks of hindlimb suspension (HS) on 100 gm male rats. After two weeks of HS and/or oral RU486 administration the animals were anesthetized, and the soleus (SOL) and extensor digitorum longus (EDL) muscles isolated and clamped at their resting length. Following an incubation series to prepare the muscle, the muscle was incubated in radioactive 3-O-methylglucose for 10 min. in the presence/absence of 75 ng/ml of IGF1, digested with 0.5 NaOH, and the amount of glucose transported measured. Two weeks of RU486 treatment significantly (P:5 0.05) elevated IGF1-stimulated glucose transport of SOL (0.576 ± 0.071 vs ...
Alterations in skeletal muscle morphology in glucose-tolerant elderlyhypertensive men: relationship to development of hypertension and heartrate. ...