• Diabetes and Metabolism Journal
• /
• v.42 no.6
• /
• pp.488-495
• /
• 2018

Background: Skeletal muscle plays a major role in glucose metabolism. We investigated the association between thigh muscle mass, insulin resistance, and incident type 2 diabetes mellitus (T2DM) risk. In addition, we examined the role of body mass index (BMI) as a potential effect modifier in this association. Methods: This prospective study included 399 Japanese Americans without diabetes (mean age 51.6 years) who at baseline had an estimation of thigh muscle mass by computed tomography and at baseline and after 10 years of follow-up a 75-g oral glucose tolerance test and determination of homeostasis model assessment of insulin resistance (HOMA-IR). We fit regression models to examine the association between thigh muscle area and incidence of T2DM and change in HOMA-IR, both measured over 10 years. Results: Thigh muscle area was inversely associated with future HOMA-IR after adjustment for age, sex, BMI, HOMA-IR, fasting plasma glucose, total abdominal fat area, and thigh subcutaneous fat area at baseline (P=0.033). The 10-year cumulative incidence of T2DM was 22.1%. A statistically significant interaction between thigh muscle area and BMI was observed, i.e., greater thigh muscle area was associated with lower risk of incident T2DM for subjects at lower levels of BMI, but this association diminished at higher BMI levels. Conclusion: Thigh muscle mass area was inversely associated with future insulin resistance. Greater thigh muscle area predicts a lower risk of incident T2DM for leaner Japanese Americans.

• Journal of Korean Neurosurgical Society
• /
• v.61 no.4
• /
• pp.509-515
• /
• 2018

Objective : In Asians, kneeling and squatting are the postures that are most often induce common peroneal neuropathy. However, we could not identify a compatible compression site of the common peroneal nerve (CPN) during hyper-flexion of knees. To evaluate the course of the CPN at the popliteal area related with compressive neuropathy using magnetic resonance imaging (MRI) scans of healthy Koreans. Methods : 1.5-Tesla knee MRI scans were obtained from enrolled patients and were retrospectively reviewed. The normal populations were divided into two groups according to the anatomical course of the CPN. Type I included subjects with the CPN situated superficial to the lateral gastocnemius muscle (LGCM). Type II included subjects with the CPN between the short head of biceps femoris muscle (SHBFM) and the LGCM. We calculated the thickness of the SHBFM and posterior elongation of this muscle, and the LGCM at the level of femoral condyles. In type II, the length of popliteal tunnel where the CPN passes was measured. Results : The 93 normal subjects were included in this study. The CPN passed through the "popliteal tunnel" formed between the SHBFM and the LGCM in 36 subjects (38.7% type II). The thicknesses of SHBFM and posterior portions of this muscle were statistically significantly increased in type II subjects. The LGCM thickness was comparable in both groups. In 78.8% of the "popliteal tunnel", a length of 21 mm to <40 mm was measured. Conclusion : In Korean population, the course of the CPN through the "popliteal tunnel" was about 40%, which is higher than the Western results. This anatomical characteristic may be helpful for understanding the mechanism of the CPNe by posture.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.23 no.2
• /
• pp.171-178
• /
• 2007

Botulinum toxin type A (BTX-A) has a local effect at the neuromuscular junction by blocking acetylcholine release and thus causing paralysis and atrophy of the affected muscles. In dentistry, Botulinum toxin type A(BTX-A) is used for the treatment of masseteric hypertrophy, temporomandibular disorder, and severe bruxism related neurologic disorder. We hypothesized that the muscle atrophy after BTX-A injection into masseter muscle in growing rats, could affect the jaw growth. The purpose of this study was to determine the effects of the BTX-A injected into the masseter muscle on the jaw growth in rats. Rats were divided into four groups(group 1; control group, group 2; saline injection group, group 3; BTX-A injection group, group 4; baseline control group). Group 4 was sacrificed at the beginning of the experiment to provide baseline values of jaw measurements. The weight, length and width of jaw in those groups were measured every weeks. This study reported that the mandibular body length, condylar length, coronoid process length, anterior region height, coronoid process height and condylar height of the jaw in BTX-A injection group were shorter than those of the control and saline injection groups(P<0.05). In conclusion, BTX-A injected into the masseter muscle may affect the undergrowth of the jaw in rats.

• Journal of Korean Academy of Nursing
• /
• v.39 no.5
• /
• pp.632-640
• /
• 2009

Purpose: The purpose of this study was to examine the effect of DHEA (Dehydroepiandrosterone) on muscle weight and Type I and II fiber cross-sectional area of affected and unaffected hindlimb muscles in rats with neuropathic pain induced by unilateral peripheral nerve injury. Methods: Neuropathic pain was induced by ligation and cutting of the left L5 spinal nerve. Adult male Sprague-Dawley rats were randomly assigned to one of two groups: The DHEA group (n=10) had DHEA injections daily for 14 days, and the Vehicle group (n=10) had vehicle injections daily for 14 days. Withdrawal threshold, body weight, food intake and activity were measured every day. At 15 days all rats were anesthetized and soleus, plantaris and gastrocnemius muscles were dissected from the both hindlimbs. Body weight, food intake, activity, muscle weight and Type I, II fiber cross-sectional area of the dissected muscles were measured. Results: The DHEA group showed significant increases (p<.05), as compared to the vehicle group for muscle weight of the unaffected plantaris, and in Type II fiber cross-sectional area of the gastrocnemius muscle. The DHEA group demonstrated a higher pain threshold than the vehicle group whereas total diet intake and activity score were not significantly different between the two groups. Conclusion: DHEA administration for 14 days attenuates unaffected plantaris and gastrocnemius muscle atrophy.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.38 no.1
• /
• pp.57-62
• /
• 2014

Most analytical models of the human body have focused on conscious responses. A patellar tendon reflex, a representative example of spinal reflexes, occurs without a neural command. Muscle forces and activation of the quadriceps femoris muscles in healthy adults during patellar tendon reflex are identified in this study. The model is assumed to move in the sagittal plane, and the thigh and the trunk are assumed to be fixed in a sitting position so that the shank can move similar to a pendulum. The knee joint is modeled as a revolute joint, and the ankle joint is modeled as a fixed joint so that the shank and the foot can be regarded as one rigid body. Muscle forces are calculated following the inverse dynamic approach. Kinematic data obtained from an experiment (Mamizuka, 2007) are used as input data. Muscle activations are identified using a Hill-type muscle model. The obtained simulation results are compared with experimental results for validating the model and the underlying assumptions.

• Asian-Australasian Journal of Animal Sciences
• /
• v.29 no.9
• /
• pp.1331-1337
• /
• 2016

The aim of this study was to compare the growth performance, fiber characteristics of the pectoralis major muscle, and meat quality characteristics in the heavy weight (HW) and random bred control (RBC) quail lines and genders. The HW male exhibited more than two times greater body (245.7 vs 96.1 g, p<0.05) and pectoralis major muscle (PMW; 37.1 vs 11.1 g, p<0.05) weights compared to the RBC female. This growth performance in the HW line was associated with a greater muscle fiber area (1,502 vs $663.0{\mu}m^2$, p<0.001) compared to the RBC line. Greater muscle mass of the HW male was accompanied by a higher percentage of type IIB fiber compared to the HW female (64.0% vs 51.0%, p<0.05). However, muscle fiber hyperplasia (increase in fiber number) has had a somewhat limited effect on PMW between the two lines. On the other hand, the HW line harboring a higher proportion of type IIB fiber showed rapid pH decline at the early postmortem period (6.23 vs 6.41, p<0.05) and lighter meat surface (53.5 vs 47.3, p<0.05) compared to the RBC line harboring a lower proportion of type IIB fiber. There were no significant differences observed in the measurement of water-holding capacity including drip loss (2.74% vs 3.07%, p>0.05) and cooking loss (21.9% vs 20.4%, p>0.05) between the HW and RBC lines. Therefore, the HW quail line developed by selection from the RBC quail, was slightly different in the meat quality characteristics compared to the RBC line, and a marked difference was found in growth performance between the two quail lines.

• Food Science of Animal Resources
• /
• v.36 no.6
• /
• pp.819-828
• /
• 2016

Muscle fiber characteristics account for meat quality and muscle fibers are mainly classified into three or more types according to their contractile and metabolic properties. However, the majority of previous studies on bovine skeletal muscle are based on myosin ATPase activity. In the present study, the differences in the characteristics of muscle fibers classified by the expression of myosin heavy chain (MHC) among four bovine skeletal muscles such as longissimus thoracis (LT), psoas major (PM), semimembranosus (SM) and semi-tendinosus (ST) and their relationships to beef quality were investigated. MHCs 2x, 2a and slow were identified by LC-MS/MS and IIX, IIA and I fiber types were classified. PM, which had the smallest size and highest density of fibers regardless of type, showed the highest myoglobin content, CIE $L^*$, $a^*$, $b^*$ and sarcomere length (p<0.05), whereas ST with the highest composition of IIX, showed high shear force and low sarcomere length (p<0.05). The correlation coefficients between muscle fiber characteristics and meat quality showed that type IIX is closely related to poor beef quality and that a high density of small-sized fibers is related to redness and tenderness. Therefore, the differences in meat quality between muscles can be explained by the differences in muscle fiber characteristics, and especially, the muscles with good quality are composed of more small-sized fibers regardless of fiber type.

• Journal of Korean Medicine Rehabilitation
• /
• v.19 no.1
• /
• pp.11-21
• /
• 2009

Objectives : This study was performed to investigate the effects of Semen Persicae(SP) on muscle type change and vascularization effect by measuring expression of Myosin heavy chain (MHC) and Vascular endothelial growth factor (VEGF) protein in the Middle cerebral artery occlusion(MCAo) rats. Methods : The middle cerebral artery was occluded, SP extraction was administrated for 4 days. The effects of SP on muscle type change and vascularization were measured. Results : 1. VEGF protein expressions in the Semen Persicae oral administration group of MCAo group were increased compared to the control group. 2. There were no significant difference between the Semen Persicae oral administration of MCAo group and the control group in MHC isoform (Type I, Type IIa) expression change. Conclusions : The present study demonstrates the effect of Semen Persicae in the vascularizing after ischemia, but has no significant effect in musle type change and the improvement of musle atrophy.

• The Journal of Korean Physical Therapy
• /
• v.19 no.5
• /
• pp.65-76
• /
• 2007

Purpose: It is generally accepted that smooth muscle contraction is triggered by intracellular $Ca^{2+}$ ($[Ca^{2+}]_i$) released from intracellular $Ca^{2+}$ stores such as sarcoplasmic teticulum (SR) and from the extracellular space. The increased $[Ca^{2+}]^i$ can phosphorylate the 20,000 dalton myosin light chain $(MLC_{20})$ by activating MLC kinase (MLCK), and this initiates smooth muscle contraction. In addition to the $[Ca^{2+}]_i$MACK-tension pathway, a number of intracellular signal molecules, including mitogen-activated protein kinase (MAPK), protein kinase C (PKC) and others, play important roles in the regulation of smooth muscle contraction. However, the mechanisms regulating contraction of depletion of SR $Ca^{2+}$ in mouse gastric smooth muscle strips is not still clear. Methods: To investigate the rotes of $Ca^{2+}$ influx and SR $Ca^{2+}$ release channel on gastric motility, isometric contraction and $[Ca^{2+}]_i$ were examined in mouse gastric smooth muscle strips. Results: High KCl, ryanodine, an activator of $Ca^{2+-}$induced $Ca^{2+}$ release channel, and cyclopiazonic acid (CPA), an inhibitor of SR $Ca^{2+-}$ATPase evoked a sustained increase in muscle contraction and $[Ca^{2+}]_i$. These increases induced by high KCl, ryanodine, and CPA were partially blocked by application of verapamil ($10{\mu}M$), a L-type $Ca^{2+}$ channel inhibitor. Additionally, in $Ca^{2+-}$free solution (1 mM EGTA), ryanodine and CPA had no effect contraction and $[Ca^{2+}]_i$ in fundic muscle strips. Conclusion: These results that extracellular $Ca^{2+}$ influx and depletion of SR trigger $Ca^{2+}$ influx through verapamil-sensitive $Ca^{2+}$ channel, and extracellular and SR $Ca^{2+}$ store may functionally involve in the subcellular $Ca^{2+}$ mobilization in mouse gastric muscle.

• Journal of the Korean Society of Physical Medicine
• /
• v.12 no.1
• /
• pp.75-81
• /
• 2017

PURPOSE: The purpose of this study was to compare the activity of the abductor hallucis (AbdH) muscle during short foot exercise (SFE) using foot orthosis (SFE-FO) and the windlass effect (SFO-WE) while sitting and in a one-leg standing position. METHODS: We recruited fourteen subjects with normal feet for this study. Surface electromyography (EMG) was used to measure the muscle activity of the AbdH muscle during SFE, SFE-FO, and SFE-WE while sitting and in a one-leg standing position. Three trials consisting of a 5 s hold for each of the three exercises were performed to measure the EMG activity of the AbdH muscle. Exercise type and position were randomly assigned. Two-way repeated-measures ANOVA was used to analyze the effects of exercise type (SFE vs. SFE-FO vs. SFE-WE) and position (sitting vs. one-leg standing position) on AbdH muscle activity. A statistical significance was set at ${\alpha}=.05$. RESULTS: The EMG activity of AbdH muscle in the SFE-WE exercise was significantly greater than that during SFE and SFE-FO in both exercise positions (p<.001). In addition, the EMG activity of the AbdH muscle in the one-leg standing position was significantly higher than that while sitting (p<.001) during all three exercises. CONCLUSION: These results suggest that SFE-WE is a more effective strengthening exercise than SFE or SFE-FO for activating the AbdH muscle.