• 한국축산식품학회지
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• 제40권1호
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• pp.132-144
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• 2020

The aim of this study was to optimize staining procedures for muscle fiber typing efficiently and rapidly in bovine and porcine skeletal muscles, such as longissimus thoracis, psoas major, semimembranosus, and semitendinosus muscles. The commercially available monoclonal anti-myosin heavy chain (MHC) antibodies and fluorescent dye-conjugated secondary antibodies were applied to immunofluorescence histology. Two different procedures, such as cocktail and serial staining, were adopted to immunofluorescence analysis. In bovine muscles, three pure types (I, IIA, and IIX) and one hybrid type, IIA+IIX, were identified by the cocktail procedure with a combination of BA-F8, SC-71, BF-35, and 6H1 anti-MHC antibodies. Porcine muscle fibers were typed into four pure types (I, IIA, IIX, and IIB) and two hybrid types (IIA+IIX and IIX+IIB) by a serial procedure with a combination of BA-F8, SC-71, BF-35, and BF-F3. Unlike for bovine muscle, the cocktail procedure was not recommended in porcine muscle fiber typing because of the abnormal reactivity of SC-71 antibody under cocktail procedure. Within the four antibodies, combinations of two or more anti-MHC antibodies allowed us to distinguish pure fiber types or all fiber types including hybrid types. Application of other secondary antibodies conjugated with different fluorescent dyes allowed us to get improved image resolution that clearly distinguished hybrid fibers. Muscle fiber characteristics differed depending on species and muscle types.

• Applied Microscopy
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• 제25권4호
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• pp.26-51
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• 1995

The present study was designed to examine effect of long term weight-training on aging atrophy in the rat skeletal muscle. Male rats of 8, 15, and 24 month old were used. Each age groups included control and weight-training for 5 months by using body press apparatus. The histo- and cytochemical, ultrastructural and stereological changes in aging skeletal muscles of the rat were observed in the present study. During the training period the body weight and muscular weight in all groups except the rectus femoris and the gastrocnemius in young age groups remained constant, but muscular weights were increased in the rectus femoris and the gastrocnemius muscles in young age groups. In trained rat, the volume density of muscle fiber type IIA and IIB were increased, but those of type IIC was decreased. Type I remained constant in 8 and 15 month old age groups, but reduced in the tibialis anterior and the gastrocnemius muscles in the 24 month old groups. Some histotological and ultrastructural changes associated with age were found: numerical increase of cytiplasmic vacuoles, lysosomes, lipofuscins, and irregularity of myofibrils. At 24 month old groups some unusual formation of contraction band and muscle splitting were observed. After weight-training, ultrastructural degenerative changes occured in the type I muscle fiber, such as splitting of muscle fiber, disorganization of myofilaments, swelling of mitochondria, accumulation of many lipid droplets, appearance of many lysosomes and residual bodies and necrotic fibers, in the old age groups. But, in the type II muscle fibers hypertrophy of muscle fiber appeared without any noticible damage as the type I. The activities of $Mg^{++}$ -ATPase decreased with age and this enzyme activities in the trained rat were significantly decreased with age. Activities of the acid phosphatase were increased with age and significantly in the trained rat. In stereological analysis, volume density of the myofibrils and the tubular system were increased, on the other hand there mitochondrial capacity was decreased. These experimental results suggested that old rats are not susceptible to be affected by weight-training as young rats, and that physical capacity of the rats must be considered when old rats are exercised for training.

• Journal of Magnetics
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• 제17권3호
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• pp.225-228
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• 2012

Muscle contusion usually results from a direct blunt impact and is frequently associated with contact sports. Muscle contusion results from microscopic muscle fiber and capillary disruption causing a microhemorrhage dissecting torn fibers and remaining viable muscle fibers. Recent studies concluded that some physical methods, including pulsed ultrasound (PU) and pulsed electromagnetic field (PEMF) treatment, accelerate and facilitate wound healing, improve scar quality and have beneficial effects on muscle and tendon healing. However, there are few studies on the effects of the early use of physical methods, such as PU and PEMF, on the expression of neurotrophic factors. The objective of this study was to investigate the effects of the early application of PU and PEMF, measured through the expression of BDNF in the muscles (gastrocnemius) and spinal cords of rats after skeletal muscle contusion. In the spinal cords and muscles, there was a significant increase of BDNF expression in the PEMF and PU groups, a greater increase was found in the PEMF group than in the PU group. In conclusion, PEMF is a useful therapeutic method that improves muscle healing after muscle contusion.

• Journal of Yeungnam Medical Science
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• 제16권1호
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• pp.125-130
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• 1999

저자들은 최근 25세 여자 환자로 뚜렷한 가족력이 없으면서 3-4세경부터 발생한 근육의 강직현상과 현저한 근비대소견이 있는 환자를 경험하였다. 임상적으로 타진성 근긴장증을 보이고 전기생리적 검사로 새끼손가락 외향근에서의 운동과 반복신경자극에서 복합근육활동전위의 감소를 보였으며, 이두박근의 근생검 소견상 용적이 증가된 근섬유와 중심핵화현상이 관찰되었다. 환자는 mexiletin 경구 투여후 근육의 강직현상이 다소 호전되었다. 이에 문헌고찰과 함께 Becker형 선천성 근긴장증 1례를 보고하는 바이다.

• 동의생리병리학회지
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• 제22권6호
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• pp.1454-1461
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• 2008

In oriental medicine, it is known that Eucommiae Cortex (EC) has strengthening and rehabilitative effects on the bone-muscle dysfunction. This study aimed to evaluate the effect of EC on the skeletal muscle atrophy. The muscle atrophy was induced by unilateral transection of the sciatic nerve in Sprague-Dawley rats. EC (water-extract, 170mg/100 g body weight) was treated once a day for 12 days. In this study, the effect of EC examined the muscle weight of hind limb, cross section areas of muscle fibers, fiber type compositions, apoptosis related factors (Bax and Bcl-2). EC reduced muscle atrophy in soleus (SOL), medial gastrocnemius (MGT), extensor digitorum longus, and tibialis posterior significantly in the damaged hind limb. EC increased type-I muscle fibers and decreased type-II muscle fibers significantly in SOL of the damaged hind limb. EC enlarged cross section areas of type-I and type-II muscle fibers significantly in SOL. EC enlarged cross section areas of type-I and type-II muscle fibers significantly in. EC reduced apoptotic nuclei and atrophic muscle fibers in SOL and MGT. EC reduced Bax positive muscle nuclei in SOL and MGT. EC up-regulated Bcl-2 positive muscle fibers in SOL and MGT. These results suggest that EC has an anti-atrophic effect and anti-apoptotic effect against myonuclear apoptosis induced by the peripheral nerve damage.

• Animal Bioscience
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• 제35권6호
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• pp.847-857
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• 2022

Objective: The effects of maternal undernutrition during midgestation on muscle fiber histology, myosin heavy chain (MyHC) expression, methylation modification of myogenic factors, and the mammalian target of rapamycin (mTOR) signaling pathway in the skeletal muscles of prenatal and postnatal goats were examined. Methods: Twenty-four pregnant goats were assigned to a control (100% of the nutrients requirement, n = 12) or a restricted group (60% of the nutrients requirement, n = 12) between 45 and 100 days of gestation. Descendants were harvested at day 100 of gestation and at day 90 after birth to collect the femoris muscle tissue. Results: Maternal undernutrition increased (p<0.05) the fiber area of the vastus muscle in the fetuses and enhanced (p<0.01) the proportions of MyHCI and MyHCIIA fibers in offspring, while the proportion of MyHCIIX fibers was decreased (p<0.01). DNA methylation at the +530 cytosine-guanine dinucleotide (CpG) site of the myogenic factor 5 (MYF5) promoter in restricted fetuses was increased (p<0.05), but the methylation of the MYF5 gene at the +274,280 CpG site and of the myogenic differentiation (MYOD) gene at the +252 CpG site in restricted kids was reduced (p<0.05). mTOR protein signals were down-regulated (p<0.05) in the restricted offspring. Conclusion: Maternal undernutrition altered the muscle fiber type in offspring, but its relationship with methylation in the promoter regions of myogenic genes needs to be elucidated.

• 대한전기학회논문지:전력기술부문A
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• 제48권11호
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• pp.1476-1478
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• 1999

A musculotendon model is proposed to predict muscle force during muscle fatigue due to the continuous functional electrical stimulation(FES). Muscle fatigue dynamics can be modeled as the electrical admittance of muscle fibers and included in activation dynamics based on the{{{{ { Ca}^{2+ } }}}} kinetics. The admittance depends on the fatigue variable that monotonically increase or decrease if electrical pulse exists or not, and on the stimulation parameters and the number of applied pulses. In the response of the change in activation the normalized Hill-type contraction dynamics connected with activation dynamics decline the muscle shortening velocity and thus its force under muscle fatigue. The computer simulation shows that the proposed model can express the muscle fatigue and its recovery without changing any stimulation parameters.

• Applied Microscopy
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• 제27권3호
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• pp.333-346
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• 1997

The ischemia and reperfusion injury of the skeletal muscles is caused by generation of reactive oxygen during ischemia and reperfusion. It is well known that over 4 hours of ischemia injures the skeletal muscles irreversibly. The author has demonstrated the effects of SOD (superoxide dismutase), DMTU (dimethyl thiourea) and ischemic preconditioning on ultrastructural changes of the muscle fibers in the rectus femoris muscles after 4 hours of ischemia and 1 day and 3 days of reperfusion. A total of 72 healthy Sprague-Dawley rats weighing from 200 gm to 250 gm were used as experimental animals. Under urethane(1.15 g/kg, IP, 2 times) anesthesia, lower abdominal incision was done and the left common iliac artery was occluded by using vascular clamp for 4 hours. The left rectus femoris muscles were obtained at 1 and 3 days after the removal of vascular clamp. The SOD (15,000 unit/kg) or DMTU (500 mg/kg) were administered intraperitoneally at 1 hour before induction of ischemia. The ischemic preconditioned group underwent three episodes of 5 minutes occlusion and 5 minutes reperfusion followed by 4 hours of ischemia and 1 day and 3 days of reperfusion. The specimens were sliced into $1mm^3$ and prepared by routine methods for electron microscopic observation. All specimens were stained with uranyl acetate and lead citrate and then observed with Hitachi-600 transmission electron microscope. The results were as follows: 1. SOD or DMTU alone did not affect the ultrastructure of muscle fibers in the rectus femoris muscles. The electron density of mitochondrial matrix was decreased by ischemic preconditioning. 2. Dilated cisternae of sarcoplasmic reticulum, triad, mitochondria and the loss of myofilament in the sarcomere were observed in the 4 hours ischemia and 1 day reperfused rectus femoris muscles. Markedly changed sarcoplasmic reticulum, triad, disordered or loss of myofilament, indistinct A-band and I-band, and irregular electron lucent M -line and Z-line are seen in the 4 hours ischemia and 3 days reperfused rectus femoris muscles. 3. SOD reduced the changes of organelles in the muscle fibers of the 4 hours ischemia and 1 day reperfused rectus femoris muscles of the rats, but SOD did not affect the changes of muscle fibers in the 4 hours ischemia and 3 days reperfused muscles. On the other hand, DMTU markedly attenuated considerably the ultrastructural change of the 4 hours ischemia and 1 day or 3 days reperfused rectus femoris muscles. 4. By the ischemic preconditioning, the change was attenuated remarkably in the 4 hours ischemia and 1 day reperfused rectus femoris muscles. As the ischemic reperfused changes of muscle fibers were regenerated or recovered by ischemic preconditioning, the ultrastructures of them were similar to those of normal control in the 4 hours ischemia and 3 days reperfused rectus formoris muscles. Consequently, it is suggested that DMTU is stronger inhibitor to ischemic reperfused change than SOD. The ischemia and reperfusion-induced muscular damage is remarkably inhibited by ischemic preconditioning.

• BMB Reports
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• 제53권5호
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• pp.278-283
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• 2020

Muscle fibers are generally formed as multinucleated fibers that are differentiated from myoblasts. Several reports have identified transcription factors and proteins involved in the process of muscle differentiation, but the roles of microRNAs (miRNAs) in myogenesis remain unclear. Here, comparative analysis of the miRNA expression profiles in mouse myoblasts and gastrocnemius (GA) muscle uncovered miR-3074-3p as a novel miRNA showing markedly reduced expression in fully differentiated adult skeletal muscle. Interestingly, elevating miR-3074-3p promoted myogenesis in C2C12 cells, primary myoblasts, and HSMMs, resulting in increased mRNA expression of myogenic makers such as Myog and MyHC. Using a target prediction program, we identified Caveolin-1 (Cav1) as a target mRNA of miR-3074-3p and verified that miR-3074-3p directly interacts with the 3' untranslated region (UTR) of Cav1 mRNA. Consistent with the findings in miR-3074-3p-overexpressing myoblasts, knockdown of Cav1 promoted myogenesis in C2C12 cells and HSMMs. Taken together, our results suggest that miR-3074-3p acts a positive regulator of myogenic differentiation by targeting Cav1.

• Anatomy and Cell Biology
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• 제56권1호
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• pp.145-149
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• 2023

Agenesis or congenital hypoplasia of skeletal muscles occurs infrequently but may occur with specific conditions such as Poland syndrome. The trapezius muscle can vary in the extent of its bony attachments or may have additional slips, however congenital absence or hypoplasia is extremely rare. There are only a few reports of partial or complete absence of the trapezius muscle. Two cases of bilateral absence of the trapezius were both in males and were accompanied by the absence of additional muscle in the pectoral girdle. Herein, we describe a case of a 56-year-old male cadaver with bilateral hypoplasia of the trapezius. The muscle was largely represented by atrophied muscle fibers with an abundance of fibrotic or fatty connective tissue. This subject had very minor hypoplasia of the left pectoralis major muscle, but the remaining muscles of the pectoral girdle were normal. The spinal accessory nerve terminated in the sternocleidomastoid muscle on both sides, failing to reach the trapezius. We interpret these findings to be consistent with a minor variant of Poland syndrome.