• The Journal of Korean Physical Therapy
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• 제13권1호
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• pp.237-243
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• 2001

Skeletal muscle cells are activated by ${\alpha}$-motorneurons which release acetylcholine at the neuromuscular junction. This results in a local depolarization of surface membrane which triggers an action potential. The action potential propagates along the surface membrane and also into the T-tubule system. In the triads T-tubules are in close connection with the terminal cisternae of the sarcoplasmic reticulum(SR). The action potential activaies T-tubule voltage sensors(DHP receptors). which activates SR Ca$^{2+}$ release channels(ryanodinc receptors). Ca$^{2+}$ have a key role in skeletal muscle in that an increase of free myoplasmic Ca$^{2+}$ concentration. The process of coupling chemical and electrical signals at the cell surface to the intracellular release of Ca$^{2+}$and ultimate contraction of muscle fibers is termed excitation-contraction coupling(ECC). Coupling of cel1 surface signals to intracellular Ca$^{2+}$ release proceeds by several mechanisms in skeletal muscle cells. This review focus on sarcopiasmic reticulum(SR) Ca$^{2+}$ releasing mechanisms from sarcoplasmic reticulum in the skeletal muscle. The mechanisms include DCCR, CICR, and HCR.

• Food Science and Biotechnology
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• 제16권1호
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• pp.49-54
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• 2007

The effects of hydrostatic pressure (HP) treatment on the physicochemical, morphological, and textural properties of bovine semitendinosus (ST) muscle were assessed. Based on SDS-PAGE, the decrease in HP-treated ST muscle protein solubility in 0.1 M KCl buffer (pH 7.0) was attributable to a reduction in the levels of sarcoplasmic protein, and the protein solubility decrease observed in 0.6 M KCl buffer (PH 7.0) was attributable to a reduction in the levels of myosin heavy-chain and actin. Scanning electron microscope (SEM) observations showed that muscle fibers became finer and more compact with increasing pressures. The shear force and hardness of ST muscle pressurized to 300 MPa decreased significantly (p<0.05), however samples pressurized at 100 and 500 MPa exhibited a significant increase in both attributes relative to the control sample (p<0.05).

• Applied Microscopy
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• 제50권
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• pp.9.1-9.8
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• 2020

The fine structural characteristics of cardiac muscle cells and its myofibril organization in the orb web spider N. clavata were examined by transmission electron microscopy. Although myofibril striations are not remarkable as those of skeletal muscles, muscle fibers contain multiple myofibrils, abundant mitochondria, extensive sarcoplasmic reticulum and transverse tubules (T-tubules). Myofibrils are divided into distinct sarcomeres defined by Z-lines with average length of 2.0 ㎛, but the distinction between the A-band and the I-bands is not clear due to uniform striations over the length of the sarcomeres. Dyadic junction which consisted of a single T-tubule paired with a terminal cisterna of the sarcoplasmic reticulum is found mainly at the A-I level of sarcomere. Each cell is arranged to form multiple connections with neighboring cells through the intercalated discs. These specialized junctions include three types of intercellular junctions: gap junctions, fascia adherens and desmosomes for heart function. Our transmission electron microscopy (TEM) observations clearly show that spider's cardiac muscle contraction is controlled by neurogenic rather than myogenic mechanism since each cardiac muscle fiber is innervated by a branch of motor neuron through neuromuscular junctions.

• Asian-Australasian Journal of Animal Sciences
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• 제28권8호
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• pp.1171-1177
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• 2015

The objective of this study was to establish the optimum protocol for the isolation and culture of porcine muscle satellite cells. Mononuclear muscle satellite cells are a kind of adult stem cell, which is located between the basal lamina and sarcolemma of muscle fibers and is the primary source of myogenic precursor cells in postnatal muscle. Muscle satellite cells are a useful model to investigate the mechanisms of muscle growth and development. Although the isolation and culture protocols of muscle satellite cells in some species (e.g. mouse) have been established successfully, the culture system for porcine muscle satellite cells is very limited. In this study, we optimized the isolation procedure of porcine muscle satellite cells and elaborated the isolation and culture process in detail. Furthermore, we characterized the porcine muscle satellite cells using the immunofluorecence. Our study provides a reference for the isolation of porcine muscle satellite cells and will be useful for studying the molecular mechanisms in these cells.

• 대한간호학회지
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• 제26권2호
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• pp.271-280
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• 1996

The purpose of this study was to determine the effect of periodic walking during hindlimb suspension on the mass, relative weight, fiber type distribution and cross-sectional area of Type I and II fibers in the developing Type II plantaris muscle. To examine the effectiveness of periodic walking on mass and fiber size, the hindlimbs of young female Wistar rats were suspended (HS group) and half of these rats walked on a treadmill for 45 min／day(15 min every 4 hours) at 5 meters／min at a 15 degree grade(HS-W group) After seven days of hindlimb suspension, the plantaris muscle wet weight was 28.40％ significantly smaller（P＜0.005） and relative plantaris muscle weight was 26.97％ smaller compared with those of control rats（P＜0.05）. The plantaris muscle wet weight and the relative plantaris muscle weight increased by 46.60％ and 49.23％ respectively with periodic walking, moreover. the plantaris muscle wet weight and the relative plantaris muscle weight of the HS-W rats recovered to the level of the control rats. No change was observed in fiber type percentage of the developing plantaris muscle following one week of hindlimb suspension or periodic walking during hindlimb suspension. Type I and II fiber cross-sectional areas of the developing plantaris muscle were 42.51％ and 43. 68％ lower in the HS group than in the control group（p＜0.0001）, Type I and II fiber cross-sectional areas of the developing plantaris were 30.82％ and 45.97％ greater in the HS-W group than in the HS group（p＜0.0001）, whereas Type I and II fiber cross-sectional area of HS-W group were less than those of the control group（P＜0.0001） The results suggest that periodic walking can attenuate developing plantaris muscle atrophy induced by hindlimb suspension.

• 한국전문물리치료학회지
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• 제17권1호
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• pp.77-85
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• 2010

This study was conducted to find the effects of scapular taping on muscle activities of the scapular rotators and upper trapezius pain in subjects with upper trapezius pain. Fifteen male subjects were recruited from Yonsei University for this study. Muscle activity of upper trapezius, lower trapezius, and serratus anterior was measured using surface electromyography. Visual analog scale was used for measuring upper trapezius pain. The subjects were asked to maintain $90^{\circ}$ shoulder flexion position with holding a 1 kg dumbbell in standing position. Scapular taping was applied over the muscle belly of the upper trapezius and attached parallel with the lower trapezius muscle fibers. For normalization, % maximal voluntary isometric contraction (%MVIC) was conducted. Paired t-test was applied to compare the muscle activities of scapular rotator and upper trapezius pain before and after applying the scapular taping. The muscle activity of the upper trapezius muscle and serratus anterior decreased significantly after tape application (p<.05). However, no significant difference was observed in lower trapezius muscle. The level of pain in the upper trapezius muscle significantly decreased after tape application (p<.05). The results of this study suggest that scapular taping can be used an additional therapy for reducing muscle activity of upper trapezius, serratus anterior and upper trapezius pain during shoulder flexion in patient with upper trapezius pain.

• 대한물리의학회지
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• 제10권1호
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• pp.71-82
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• 2015

PURPOSE: The aim of this study is to compare changes in the thickness of the gluteus medius muscle fiber between chronic low back pain(clbp) with gluteus medius weakness and healthy subject. METHODS: Ultrasound imaging was used to measure in the thickness of each fiber of the gluteus medius muscle based on maximal muscle contraction during abduction motion of the hip joint in a healthy group (11 subjects) and a chronic CLBP group (21 subjects). An independent t-test was performed to analyze the difference of thickness in each fiber of the gluteus medius muscle and the rate of changes in the fibers in the two groups. RESULTS: The fiber thickness changes in the gluteus medius muscle were significantly lower for the posterior fiber in the CLBP group compared to the healthy group (p<0.01). The changes in rate of difference of thickness the posterior part of the gluteus medius muscle was significantly lower in the CLBP group than in the healthy group (p<0.05). CONCLUSION: The findings of this study CLBP patients with weakness of the gluteus medius muscle that lower for the posterior fiber's difference of thickness and rate of change in the CLBP group compared to the healthy group. Indicate that rehabilitation of CLBP patients with weakness of the gluteus medius muscle should consider the functions of posterior fiber of the gluteus medius muscle.

• 대한수의학회지
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• 제34권3호
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• pp.435-439
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• 1994

The present observation was focussed mainly on the histopathological and immunohistochemical finding of the tumor developing from the outside of rat uterus wall. In gross finding, this tumor were a oval form mass and 0.75cm and 1cm in greatest demension. The sectioned surface showed uniform, solid, gray-white. In histopathological finding, the tumor showed the form of lymphoid nodule-like structure and was composed of the cells with karryorrhexis, karyolysis and necrosis in the central zone, mature cells in the paracentral zone, and concentric layers of compressed, flattened and atrophied smooth muscle fibers by the proliferating of the cells closely resembling endometrial stromal ells in the peripheral zone and a few smaller nodule-like structure in certain areas of the peripheral zone. In immunohistochemical observations, the proliferating cells presents only among the concentric layers of the smooth muscle fibers in the peripheral zone. Labeling index of proliferating cells in the peripheral zone was $4.34{\pm}1.28%$. These tumor cells did not metastasized in another orgns and labeling index was low, So it was concluded that this tumor was benign stomal sarcoma.

• 대한수의학회지
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• 제33권2호
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• pp.301-308
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• 1993

Three or 7day old piglets were infected experimentally with different encephalomyocarditis virus isolates to detect the viral antigen by the immunoperoxidase technique and to observe strain difference in their pathogenecity in newborn pigs by comparing clinical signs and pathologic lesions. Clinical signs of the infected pigs were different depending on the virus strain, pig age and infection route. Encephalomyocarditis virus(EMCV) NVSL-PR isolate was more pathogenic than MN-25 and MN-30 isolate. Three day old piglets showed more severe illness than 7 day old piglets. Predominant clinical signs were sudden death without noticeable clinical signs and dyspnea manifested as heavy abdominal breathing. Contact-infection from infected piglets to controls was observed in the oro-nasally infected group but not the intramuscular group. Common necropsy findings of dead piglets in both age groups infected with MN-25 and NVSL-PR were accumulation of excessive fluid in the body cavities and mild to diffuse necrotic areas observed in the hearts and occasionally in the livers. Microscopically, myocarditis with inflammatory cell infiltration, necrosis of the myocardial muscle fibers and occasional mineralization were observed along with interstitial pneumonia and centrolobular necrosis in the liver. Using an immunoperoxidase technique, viral antigen was detected in myocardial muscle fibers of piglets infected with EMCV.

• Journal of Ginseng Research
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• 제43권3호
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• pp.475-481
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• 2019

Background: The ginsenoside Rg1 has been shown to exert various pharmacological activities with health benefits. Previously, we have reported that Rg1 promoted myogenic differentiation and myotube growth in C2C12 myoblasts. In this study, the in vivo effect of Rg1 on fiber-type composition and oxidative metabolism in skeletal muscle was examined. Methods: To examine the effect of Rg1 on skeletal muscle, 3-month-old mice were treated with Rg1 for 5 weeks. To assess muscle strength, grip strength tests were performed, and the lower hind limb muscles were harvested, followed by various detailed analysis, such as histological staining, immunoblotting, immunostaining, and real-time quantitative reverse transcription polymerase chain reaction. In addition, to verify the in vivo data, primary myoblasts isolated from mice were treated with Rg1, and the Rg1 effect on myotube growth was examined by immunoblotting and immunostaining analysis. Results: Rg1 treatment increased the expression of myosin heavy chain isoforms characteristic for both oxidative and glycolytic muscle fibers; increased myofiber sizes were accompanied by enhanced muscle strength. Rg1 treatment also enhanced oxidative muscle metabolism with elevated oxidative phosphorylation proteins. Furthermore, Rg1-treated muscles exhibited increased levels of anabolic S6 kinase signaling. Conclusion: Rg1 improves muscle functionality via enhancing muscle gene expression and oxidative muscle metabolism in mice.