• Korean Journal of Agricultural Science
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• v.45 no.1
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• pp.50-57
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• 2018

Meat comes from the skeletal muscles of farm animals, such as pigs, chickens, and cows. Skeletal muscles are composed of many muscle fibers. Muscle fibers are categorized into three types, fiber type I, IIA, and IIB, based on their contractile speed and metabolic properties. Different muscle fiber types have different biochemical, physiological, and biophysical characteristics. Especially, the characteristics of muscle fiber type I and IIB are opposite to each other. Muscle fiber type I has a relatively strong oxidative metabolic trait and a higher content of lipids. In contrast to fiber type I, muscle fiber type IIB has a strong glycolytic metabolic trait and a relatively lower content of lipids and a higher content of glycogen. Muscle fiber type IIA has intermediate properties between fiber type I and IIB. Thus, muscles with different fiber type compositions exhibit different ante- and post-mortem muscle characteristics. In particular, the different metabolic traits of muscles due to the different compositions of the fiber types strongly affect the biochemical and physiological processes during the conversion of muscle to meat and subsequently influence the quality of the meat. Therefore, understating muscle metabolism and muscle fiber characteristics is very important when discussing the traits of meat quality. This review is an overview on basic muscle metabolism, muscle fiber characteristics, and their influence on meat quality and finally provides a comprehensive understanding about the fundamental traits of muscles and meat quality.

• Journal of Acupuncture Research
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• v.18 no.1
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• pp.170-185
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• 2001

Objective : This experimental study was designed to investigate the effect of Chaenomelis fructus herbal acupuncture on the soleus muscle and tibialis anterior muscle of hindlimb-suspended rats. The measurement have been performed on the composition of type I, type IIa and type IIb muscle fibers in the soleus muscle and tibialis anterior muscie - histochemical study. Materials and Methods : Sprague-Dawley rats weighing about 250g were subjected to hindlimb suspension and divided into six groups; 1. Normal group: normai group 2. Control group: group of hindlimb suspension for 7 days 3. NT group: non-treatment group for 2 or 4 weeks after 7days of hindlimb suspension. 4. EX gtoup: running exercise group for 2 or 4 weeks after 7days of hindlimb suspension. 5. HA group: administration of Chaenomelis fructus herbal acupuncture during 2 or 4 weeks after 7 days of hindlimb suspension. 6. EXHA group: administration of Chaenomelis fructus herbal acupuncture and running exercise during 2 or 4 weeks after 7 days of hindlimb suspension. Results Results : 1. The composition of type I muscle fibers in the soleus muscle significantly increased in 2 or 4 weeks HA and EXHA groups more than control group, and the composition of type IIa muscle fibers in the soleus muscle significantly decreased in 2 or 4 weeks HA and EXHA goups more than control group. 2. The composition of type I muscie fibers in the tibialis anterior muscle significantly increased in 2 or 4 weeks HA and EXHA groups more than control group, and the composition of type IIb muscle fibers in the soleus muscle significantly decreased in 2 or 4 weeks HA and EXHA groups more than control group. 3. The size of type I muscle fibers in the soleus muscle significantly increased in 2 or 4 weeks HA and EXHA groups more than control group, and the size of type IIa muscle fibers in the soleus muscle significantly increased in 2 weeks EXHA group and 4 weeks HA and EXHA groups more than control group. 4. The size of type I, IIa muscle fibers in the tibialis anterior muscle significantly increased in 2 or 4weeks HA, EXHA and EX groups more than control group, and the size of type IIb muscle fibers significantly increased in 2 weeks EXHA group and 4 weeks HA, EXHA and EX groups more than control group. 5. The capiliaries number per fiber of muscle fibers in the soleus and tibialis anterior muscle showed no differences in all experimental groups more than control group. Conclusion : According to the above results, it is shown that Chaenomelis fructus herbal acupuncture could be effective in the treatment of muscle atrophy.

• Journal of Korean Academy of Nursing
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• v.36 no.7
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• pp.1232-1241
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• 2006

Purpose: The purpose of this study was to examine the effects of cerebral ischemia on Type I(soleus) and Type II(plantaris, gastrocnemius) muscles, and to determine the effects of isometric contraction training by electro- stimulation on Type I and II muscles in cerebral ischemia model rats. Method: Twenty-five male Sprague-Dawley rats were randomly divided into four groups: ST(stroke), STES(stroke+electrostimulation), SH(sham) and SHES (sham+electrostimulation). The ST and STES groups received a transient right middle cerebral artery occlusion operation. The SH and SHES groups received a sham operation. The STES and SHES groups had daily isometric contraction training by electrostimulation(100Hz, 45mA, 7.5V) on hindlimb muscles for 7days. Result: Plantaris and gastrocenmius muscle weight, myofibrillar protein contents of soleus and gastrocnemius, and the muscle fiber cross-sectional area of gastrocnemius in the ST group significantly decreased compared with the SH group. Soleus, plantaris, gastrocnemius muscle weight, myofibrillar protein contents of soleus and gastrocnemius, and the Type I muscle fiber cross-sectional area of soleus and the Type II muscle fiber cross-sectional area of gastrocnemius in the STES group significantly increased compared with the 57 group. Conclusion: Hindlimb muscle atrophy occurs after acute stroke and isometric contraction training by electrostimulation during early stages of a stroke attenuates muscle atrophy of Type I and Type II muscles.

• Journal of Korean Academy of Nursing
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• v.26 no.2
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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.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.1 no.2
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• pp.21-30
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• 2003

The purpose of this study was to know the effect of aquatic-exercise on muscle atrophy which induced by steroid injection. The forty-eight Sparague-Dawley adult male rats were assigned to the 4 groups; GroupI(distilled water injection), GroupII(steroid injection), GroupIII(distilled water injection and aquatic exercise), GroupIV(steroid injection and aquatic exercise). We observed their body weight, histological change by PAS stein. The results of this study were as follows; 1. After 2 weeks, the change of weights appeared that non-steroid injection groups increase weight and steroid injection groups decreased weight hasty. after 4 weeks, weights recovered from weight before test. It was possible to explain the change of weight by type II muscle fiber increase. 2. In histological change of muscle fibers, atrophy didn't observed in test group I, because type II muscle fibers were developed well. we observed not only injury of muscle fiber and muscle atrophy but specifically grouping type I muscle fiber in test group II. normal arrangement of muscle fibers were visible in test group and type II muscle fibers increased. we could observe muscle recovery because of type II muscle fibers increase in test group IV. therefore, it was seem that type II cell was recovering through aquatic exercise.

• Journal of Life Science
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• v.23 no.12
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• pp.1509-1515
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• 2013

The term lipotoxicity has been used to describe how excess lipid accumulation leads to cellular dysfunction and death in non-adipose tissues, including skeletal muscle. While lipotoxicity has been found in cultured skeletal muscle cells with high-fat feeding, the consequences of lipotoxicity in vivo are still unknown, particularly in Type-I muscle, which is metabolically affected by lipotoxicity. The aim of this study was to investigate the effects of a high-fat diet on changes in the morphology and apoptotic protein expression of Type-I muscle loss in rats. The rats were fed either a high-fat diet or a normal diet for six weeks, and then lipid accumulation, inflammation response, and nucleus infiltration were measured, and PARP protein expression was cleaved by Oil Red O staining, H & E staining, and Western blot, respectively. Lipid accumulation, inflammation response, nucleus infiltration, and cleaved PARP protein expression were significantly (p<0.05) higher in the high-fat diet group than they were in the normal diet group. The weight of Type-I muscle tended to be lower in the high-fat diet group compared to the normal diet group, but the difference was not statistically significant. These results indicate that a high-fat diet triggers cell death in Type-I muscle via lipotoxicity, which suggests that a high-fat diet may be associated with sarcopenia.

• Journal of Korean Academy of Nursing
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• v.32 no.5
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• pp.727-734
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• 2002

This study was to determine the effect of DHEA administration before, during, and after dexamethasone treatment on body weight and TypeI,II muscle weight of rat receiving dexamethasone treatment. Method: Wistar rats were divided into 6 groups: control(C), dexamethasone(D), DHEA administration for 3days after dexamethasone treatment for 7days(7D+3DH), dexamethasone treatment for 7days after DHEA administration for 3days(3DH+7D), DHEA administration during dexamethasone treatment for 4days after dexamethasone treatment for 3days(3D+4DDH), DHEA administration during dexamethasone treatment for 7days(7DDH). Dexamethasone was injected by subcutaneously daily at a dose of 5mg/kg. DHEA was orally administered daily at a dose of 5mg/kg for 7 days. Soleus(TypeI) muscle, and both plantaris and gastro- cnemius(TypeII) muscles were dissected on the 7th day of experiment. Result: Body weight of both 3DH+7D group and 3D+4DDH group increased significantly compared with that of 7D group. Body weight of 7D+3DH group decreased significantly compared with that of 7D group, 7DDH group, 3DH+7D group and 3D+4DDH group. Muscle weight of both plantaris and gastro- cnemius tended to decrease compared with that of 7D group. Muscle weight of 7DDH group, 3D+4DDH group and 3DH+7D group increased significantly compared with that of 7D+3DH group. Muscle weight of gastrocnemius of both 3DH+7D group and 3D+4DDH group increased significantly compared with that of 7D group. Conclusion: Based on these results, it can be suggested that DHEA administration before and during dexamethasone treatment can increase both body weight and mass of atrophied TypeII muscle induced by dexa- methasone treatment.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.1 no.1
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• pp.73-85
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• 2003

The purpose of this study is to discuss and analyze the change of GLUT-4 and muscle fiber type of streptozotocin(STZ)-diabetic rats over a period of 6 weeks. We divided into four groups; I(aquatic exercise and feeding of Cordyceps militaris; n=6), test group II(feeding of Cordyceps miliaris; n=6), test group III(aquatic exercise; n=6), control group IV(non-treatment; n=6). After experimenting we measured the blood glucose, body weight, muscle fiber type and GLUT-4 protein content. The change of glucose levels decreased greater in group I than the other group. The body weight gain was lower in the all groups. The change femoris muscle fiber type, the size of muscle fiber TypeII lessened more than the one of Type I in group IV. Decrease of muscle fiber size more diminishment in group I than the other group. GLUT-4 protein quantity decrease in group IV compared to normal group. It was significantly increased in group. I, III compared to group IV. But there was more increase in group I (p<.001). These results suggest that GLUT-4 and muscle fiber type II decrease in STZ-diabetic rats and that when we apply aquatic exercise and feeding of Cordyceps militaris in diabetic rats over a period 6 weeks, it is increase GLUT-4 and the increase of insulin sensitivity of peripheral tissue. So it is considered to be helpful in improvement of glucose homeostasis and in prevent from muscle atrophy resulted from complication.

• Journal of Korean Biological Nursing Science
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• v.4 no.2
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• pp.19-40
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• 2002

The purpose of this study was to determine the effect of DHEA on Type I(soleus) and II muscles(plantaris, gastrocnemius) in a focal brain ischemia model rat. Thirty-seven male Sprague-Dawley rats with $200{\sim}250g$ body weights were randomly divided into four groups : CINS(cerebral ischemia + normal saline), CIDH(cerebral ischemia + DHEA), SHNS(sham + normal saline), SHDH (sham + DHEA). Both the CINS and CIDH groups were undergone a transient right middle cerebral artery occlusion operation. In the SHNS and SHDH groups, a sham operation was done. DHEA was administered daily at a dose of 0.34mmol/kg, and normal saline was administered daily at the same dose by intraperitoneal injection for 7days after operation. Cerebral infarction in the CINS and CIDH groups was identified by staining with 2% triphenyltetrazolium chloride solution for 60 minutes. The data were analyzed by Kruskal-Wallis test and Mann-Whitney U test using the SPSSWIN 9.0 program. The results were summarized as follows: 1) The muscle weights of soleus(Type I), plantaris and gastrocnemius(Type II) in CINS group were significantly less than those of the SHNS group(p<.01). The muscle fiber cross-sectional area of the CINS group was significantly less than that of the SHNS group in Type I muscle fiber of the soleus and Type II muscle fiber of the plantaris and gastrocnemius(p<.05). The myofibrillar protein content of the CINS group was significantly less than that of the SHNS group in the left gastrocnemius and right soleus(p<.05). 2) The muscle weights of the soleus, plantaris and gastrocnemius except the unaffected side of the plantaris in the CIDH significantly increased compared to those of the CINS group(p<.05). The muscle fiber cross-sectional area of the CIDH group significantly increased compared to that of the CINS group in Type II muscle fiber of the plantaris and gastrocnemius(p<.05). The myofibrillar protein content of the CIDH group significantly increased compared to that of the CINS group in the left soleus(p<.05). 3) On the post-op 8 day, the body weight of the CINS group was significantly less than that of the CIDH, SHNS and SHDH groups(p<.01). Total diet intake of the CINS and CIDH groups was significantly less than that of the SHNS and SHDH groups(p<.01). Based on these results, it was identified that muscle atrophy could be induced during the 7 days after cerebral infarction, and DHEA administration during the early stage of cerebral infarction might attenuate muscle atrophy.

• Journal of Korean Academy of Nursing
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• v.23 no.2
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• pp.207-223
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• 1993

Inpatients are mostly occupied in bed with restricted activity, nearly all patient populations are at risk for the occurrence of skeletal muscle atrophy due to decreased level of activity. Restriction of mobility is far greater in pediatric patients compared with adult patients since almost all the activities of daily living is performed by parents or caregivers. It could be assumed that pediatric patients are more vulnerable to skeletal muscle atrophy than adult patients, however, there have been no attempts to reduce the atrophy of developing muscle. Therefore it is important to determine the effect of exercise in developing muscle during decreased activity. The purpose of this study was to determine the effect of periodic weight support during hindlimb suspension on the mass and cross-sectional area of Type I and II fibers in developing soleus(Type I ) muscle. To examine the effectiveness of periodic weight support activity in maintaining mass and fiber size. the hindlimb of young female Wistar rats was suspended(HS) and half of these rats walked on a treadmill for 45min / day(15min every 4h) at 5m / min at a 15 grade(HS-WS). After 7days of hindlimb suspension, soleus wet weight was 28. 57% smaller and relative soleus weight was 28. 21% smaller in comparison with con-trol rats (p〈0.05) Soleus wet weight and relative soleus weight increased by 67.72% and 71.43% each with periodic weight support activity during hindlimb suspension (p〈0.01, p〈0.005), moreover soleus wet weight and relative soleus weight of the HS -WS rats were greater than those of the control group. No change was observed in fiber type percentage of the developing soleus muscle after 1 week of hindlimb suspension plus weight support activity. Type I and II fiber cross-sectional areas of the developing soleus muscle were 50.45% and 43.39% lower in the HS group than in the control group (p〈0.0001), type I and II fiber cross-sectional areas of the developing soleus were 24.49% and 29.93% greater in the HS - WS group than in the HS rats (p〈0.0001), whereas Type I and II fiber cross-sectional areas of HS - WS group were less than those of the control group, The results suggest that periodic weight support activity can ameliorate developing soleus muscle atrophy induced by hindlimb suspension, even in type II fibers that would not have been expected to be recruited by this type of neuromuscular demand. Clinical experimental study is needed to deter-mine the effect of periodic weight bearing exercise on developing atrophied leg muscle based on these results.