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Single muscle fiber

Avadhesh Kumar, Shalini Kaushal, Neelu Verma, Deepti Chandra
The treatment of gingival recession defects is indicated for esthetic and functional reasons to reduce root sensitivity, to remove muscle pull, to create or augment keratinized tissue, and to prevent disease progression. The presence of sufficient amount of periosteum adjacent to gingival recession defects makes it a suitable graft. The adult human periosteum is a highly vascular connective tissue with immense regenerative potential. It contains fibroblasts, osteogenic progenitor cells, and stem cells as a result of which it has the ability to differentiate into fibroblast, osteoblast, chondrocytes, adipocytes, and skeletal myocytes...
September 2016: Journal of Oral Biology and Craniofacial Research
Donald B Sanders, Janice M Massey
OBJECTIVE: To determine if single-fiber EMG (SFEMG) jitter accurately reflects change in severity in myasthenia gravis (MG). METHODS: We reviewed jitter and outcome data from all MG patients in our clinic who had at least 2 jitter measurements in the extensor digitorum (ED) or frontalis muscle. RESULTS: Change in all parameters of jitter measured with SFEMG electrodes predicted clinical change with acceptable accuracy. Absolute and percentage change in mean MCD were equally accurate in predicting clinical change and were more accurate than change in the proportion of fiber pairs with blocking or normal jitter...
October 19, 2016: Muscle & Nerve
Sampath K Gollapudi, Murali Chandra
Many studies have demonstrated that depressed myofilament Ca(2+) sensitivity is common to dilated cardiomyopathy (DCM) in humans. However, it remains unclear whether a single determinant-such as myofilament Ca(2+) sensitivity-is sufficient to characterize all cases of DCM because the severity of disease varies widely with a given mutation. Because dynamic features dominate in the heart muscle, alterations in dynamic contractile parameters may offer better insight on the molecular mechanisms that underlie disparate effects of DCM mutations on cardiac phenotypes...
2016: Frontiers in Physiology
Antonio Carlos Abramo, Thiago Paoliello Alves Do Amaral, Bruno Pierotti Lessio, Germano Andrighetto De Lima
BACKGROUND: The purpose of this study is to establish a relationship between the skin lines on the upper third of the face in cadavers, which represent the muscle activity in life and the skin lines achieved by voluntary contraction of the forehead, glabellar, and orbital muscles in patients. METHODS: Anatomical dissection of fresh cadavers was performed in 20 fresh cadavers, 11 females and 9 males, with ages ranging from 53 to 77 years. Subcutaneous dissection identified the muscle shape and the continuity of the fibers of the eyebrow elevator and depress muscles...
October 14, 2016: Aesthetic Plastic Surgery
Hannah Ogilvie, Nicola Cacciani, Hazem Akkad, Lars Larsson
Intensive care unit (ICU) patients are often overtly subjected to mechanical ventilation and immobilization, which leads to impaired limb and respiratory muscle function. The latter, termed ventilator-induced diaphragm dysfunction (VIDD) has recently been related to compromised heat shock protein (Hsp) activation. The administration of a pharmacological drug BGP-15 acting as a Hsp chaperone co-inducer has been found to partially alleviate VIDD in young rats. Considering that the mean age in the ICU is increasing, we aimed to explore whether the beneficial functional effects are also present in old rats...
2016: Frontiers in Physiology
Angela Zissler, Peter Steinbacher, Reinhold Zimmermann, Stefan Pittner, Walter Stoiber, Arne C Bathke, Alexandra M Sänger
BACKGROUND: Muscle injuries are among the most common sports-related lesions in athletes; however, optimal treatment remains obscure. Extracorporeal shock wave therapy (ESWT) may be a promising approach in this context, because it has gained increasing importance in tissue regeneration in various medical fields. HYPOTHESIS: ESWT stimulates and accelerates regenerative processes of acute muscle injuries. STUDY DESIGN: Controlled laboratory study...
October 11, 2016: American Journal of Sports Medicine
Fausto Antonio Panizzolo, Andrew J Maiorana, Louise H Naylor, Lawrence G Dembo, David G Lloyd, Daniel J Green, Jonas Rubenson
BACKGROUND: Alterations in skeletal muscle function and architecture have been linked to the compromised exercise capacity characterizing chronic heart failure (CHF). However, how passive skeletal muscle force is affected in CHF is not clear. Understanding passive force characteristics in CHF can help further elucidate the extent to which altered contractile properties and/or architecture might affect muscle and locomotor function. Therefore, the aim of this study was to investigate passive force in a single muscle for which non-invasive measures of muscle size and estimates of fiber force are possible, the soleus (SOL), both in CHF patients and age- and physical activity-matched control participants...
2016: PeerJ
Jianbo Yang, Chao Ding, Xujie Dai, Tengfei Lv, Tingbing Xie, Tenghui Zhang, Wen Gao, Jianfeng Gong, Weiming Zhu, Ning Li, Jieshou Li
BACKGROUND: Intestinal fibrosis is a late complication of pelvic radiotherapy. Epithelial-to-mesenchymal transition (EMT) plays an important role in tissue fibrosis. The aim of this study was to examine the effect of soluble dietary fiber on radiation-induced intestinal EMT and fibrosis in a mouse model. MATERIALS AND METHODS: Apple pectin (4% wt/wt in drinking water) was administered to wild-type and pVillin-Cre-EGFP transgenic mice with intestinal fibrosis induced by a single dose of abdominal irradiation of 10 Gy...
September 22, 2016: JPEN. Journal of Parenteral and Enteral Nutrition
Ben Douglas Perry, Victoria L Wyckelsma, Robyn M Murphy, Collene H Steward, Mitchell Anderson, Itamar Levinger, Aaron C Petersen, Michael John McKenna
Physical training increases skeletal muscle Na(+),K(+)-ATPase (NKA) and improves exercise performance, but the effects of inactivity per se on NKA in human muscle are unknown. We investigated the effects of 23-days unilateral lower limb suspension (ULLS) and subsequent 4-weeks resistance training (RT) on muscle function and NKA in six healthy adults, measuring quadriceps muscle peak torque; fatigue and venous [K(+)] during intense one-legged cycling exercise; and skeletal muscle NKA content ([(3)H]ouabain binding) and NKA isoform abundances (immunoblotting) in muscle homogenates (α1-3, β1-2) and in single fibers (α1-3, β1)...
September 15, 2016: Journal of Applied Physiology
Lorenzo Marcucci, Takumi Washio, Toshio Yanagida
Muscle contractions are generated by cyclical interactions of myosin heads with actin filaments to form the actomyosin complex. To simulate actomyosin complex stable states, mathematical models usually define an energy landscape with a corresponding number of wells. The jumps between these wells are defined through rate constants. Almost all previous models assign these wells an infinite sharpness by imposing a relatively simple expression for the detailed balance, i.e., the ratio of the rate constants depends exponentially on the sole myosin elastic energy...
September 2016: PLoS Computational Biology
Francesco Bombelli, Ludovico Lispi, Sandro Costanzi Porrini, Manlio Giacanelli, Chiara Terracciano, Roberto Massa, Antonio Petrucci
OBJECTIVES: Weakness and fatigue are frequent symptoms in myotonic dystrophy type 1 (DM1), mainly as a result of muscle impairment. However, neuromuscular junction (NMJ) abnormalities could play an additional role in determining these manifestations. We aimed to document the possible NMJ involvement in DM1. PATIENTS AND METHODS: In order to substantiate this hypothesis we performed low rate repetitive nerve stimulation (RNS) and single fiber electromyography (SFEMG), in 14 DM1 subjects...
November 2016: Clinical Neurology and Neurosurgery
Brittany A Edgett, Jacob T Bonafiglia, Brittany L Baechler, Joe Quadrilatero, Brendon J Gurd
This study examined changes in LRP130 gene and protein expression in response to an acute bout of sprint-interval training (SIT) and 6 weeks of SIT in human skeletal muscle. In addition, we investigated the relationships between changes in LRP130, SIRT3, and PGC-1α gene or protein expression. Fourteen recreationally active men (age: 22.0 ± 2.4 years) performed a single bout of SIT (eight, 20-sec intervals at ~170% of VO2peak work rate, separated by 10 sec of rest). Muscle biopsies were obtained at rest (PRE) and 3 h post-exercise...
September 2016: Physiological Reports
Nicholas A Kurniawan, Bart E Vos, Andreas Biebricher, Gijs J L Wuite, Erwin J G Peterman, Gijsje H Koenderink
Tissues and cells sustain recurring mechanical loads that span a wide range of loading amplitudes and timescales as a consequence of exposure to blood flow, muscle activity, and external impact. Both tissues and cells derive their mechanical strength from fibrous protein scaffolds, which typically have a complex hierarchical structure. In this study, we focus on a prototypical hierarchical biomaterial, fibrin, which is one of the most resilient naturally occurring biopolymers and forms the structural scaffold of blood clots...
September 6, 2016: Biophysical Journal
Gregory D Cartee, Edward B Arias, Carmen S Yu, Mark W Pataky
One exercise session can induce subsequently elevated insulin sensitivity that is largely attributable to greater insulin-stimulated glucose uptake by skeletal muscle. Because skeletal muscle is a heterogeneous tissue comprised of diverse fiber types, our primary aim was to determine exercise effects on insulin-independent and insulin-dependent glucose uptake by single fibers of different fiber types. We hypothesized that each fiber type featuring elevated insulin-independent glucose uptake immediately post-exercise (IPEX) would be characterized by increased insulin-dependent glucose uptake at 3...
September 6, 2016: American Journal of Physiology. Endocrinology and Metabolism
Martin O Bohlen, Susan Warren, Michael J Mustari, Paul J May
In this study, two points related to the pattern of innervation of the extraocular muscles were explored. 1. Species differences exist in the location of the motoneurons supplying multiply innervated fibers (MIFs) and singly innervated fibers (SIFs) in eye muscles. MIF motoneurons are located outside the extraocular nuclei in primates, but are intermixed with SIF motoneurons within rat extraocular nuclei. To test whether this difference is related to visual capacity and frontal placement of eyes, we injected retrograde tracers into the medial rectus muscle of the cat, a highly visual, non-primate with frontally placed eyes...
September 2, 2016: Journal of Comparative Neurology
Haruo Sugi, Maki Yamaguchi, Tetsuo Ohno, Takakazu Kobayashi, Shigeru Chaen, Hiroshi Okuyama
During muscle contraction, myosin heads (M) bound to actin (A) perform power stroke associated with reaction, AMADPPi → AM + ADP + Pi. In this scheme, A • M is believed to be a high-affinity complex after removal of ATP. Biochemical studies on extracted protein samples show that, in the AM complex, actin-binding sites are located at both sides of junctional peptide between 50K and 20K segments of myosin heavy chain. Recently, we found that a monoclonal antibody (IgG) to the junctional peptide had no effect on both in vitro actin-myosin sliding and skinned muscle fiber contraction, though it covers the actin-binding sites on myosin...
2016: PloS One
Kirkwood E Personius, Barbara S Slusher, Susan B Udin
UNLABELLED: At birth, each mammalian skeletal muscle fiber is innervated by multiple motor neurons, but in a few weeks, all but one of those axons retracts (Redfern, 1970) and differential activity between inputs controls this phenomenon (Personius and Balice-Gordon, 2001; Sanes and Lichtman, 2001; Personius et al., 2007; Favero et al., 2012). Acetylcholine, the primary neuromuscular transmitter, has long been presumed to mediate this activity-dependent process (O'Brien et al., 1978), but glutamatergic transmission also occurs at the neuromuscular junction (Berger et al...
August 24, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Giorgos K Sakellariou, Timothy Pearson, Adam P Lightfoot, Gareth A Nye, Nicola Wells, Ifigeneia I Giakoumaki, Richard D Griffiths, Anne McArdle, Malcolm J Jackson
Age-related skeletal muscle dysfunction is the underlying cause of morbidity that affects up to half the population aged 80 and over. Considerable evidence indicates that oxidative damage and mitochondrial dysfunction contribute to the sarcopenic phenotype that occurs with aging. To examine this, we administered the mitochondria-targeted antioxidant mitoquinone mesylate [[10-(4,5-dimethoxy-2-methyl-3,6-dioxo-1,4-cyclohexadien-1-yl)decyl] triphenylphosphonium; 100 μM] to wild-type C57BL/6 mice for 15 wk (from 24-28 mo of age) and investigated the effects on age-related loss of muscle mass and function, changes in redox homeostasis, and mitochondrial organelle integrity and function...
August 22, 2016: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
Greg J Grosicki, Robert A Standley, Kevin A Murach, Ulrika Raue, Kiril Minchev, Paul M Coen, Anne B Newman, Steven Cummings, Tamara Harris, Stephen Kritchevsky, Bret H Goodpaster, Scott Trappe
We examined single muscle fiber contractile function of the oldest-old (3F/2M, 89 ± 1 yr old) enrolled in The Health, Aging, and Body Composition Study (The Health ABC Study). Vastus lateralis muscle biopsies were obtained and single muscle fiber function was determined (n = 105) prior to myosin heavy chain (MHC) isoform identification with sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cross-sectional area of MHC I muscle fibers (5,576 ± 333 μm(2); n = 58) was 21% larger (P < 0.05) than MHC IIa fibers (4,518 ± 386 μm(2); n = 47)...
October 1, 2016: Journal of Applied Physiology
Monica Llano-Diez, Arthur J Cheng, William Jonsson, Niklas Ivarsson, Håkan Westerblad, Vic Sun, Nicola Cacciani, Lars Larsson, Joseph Bruton
BACKGROUND: Critical illness myopathy is an acquired skeletal muscle disorder with severe myosin loss and muscle weakness frequently seen in intensive care unit (ICU) patients. It is unknown if impaired excitation-contraction coupling contributes to the muscle weakness. METHODS: We used a unique ICU model where rats were deeply sedated, post-synaptically pharmacologically paralyzed, mechanically ventilated and closely monitored for up to ten days. Single intact fibers from the flexor digitorum brevis muscle were isolated and used to measure force and free myoplasmic [Ca(2+)] ([Ca(2+)]i) during tetanic contractions...
August 10, 2016: Critical Care: the Official Journal of the Critical Care Forum
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