• Molecules and Cells
• /
• v.24 no.3
• /
• pp.441-444
• /
• 2007

Despite the importance of cell fate decisions regulated by epigenetic programming, no experimental model has been available to study transdifferentiation from myoblasts to smooth muscle cells. In the present study, we show that myoblast cells can be induced to transdifferentiate into smooth muscle cells by modulating their epigenetic programming. The DNA methylation inhibitor, zubularine, induced the morphological transformation of C2C12 myoblasts into smooth muscle cells accompanied by de novo synthesis of smooth muscle markers such as smooth muscle ${\alpha}$-actin and transgelin. Furthermore, an increase of p21 and decrease of cyclinD1 mRNA were observed following zebularine treatment, pointing to inhibition of cell cycle progression. This system may provide a useful model for studying the early stages of smooth muscle cell differentiation.

• Biomedical Science Letters
• /
• v.29 no.4
• /
• pp.296-301
• /
• 2023

This study was conducted to induce muscle loss using dexametasone and then use the extract to determine its effectiveness in a muscle loss animal model. Animal experimental groups were divided by five groups. Changes in the weight of the animals were measured for a total of 5 weeks. After animal sacrifice, muscle mass was measured, and animal behavior evaluation was conducted using grip strength test and pole test. The expression levels of MAFbx protein was measured using muscle samples. Oral administration of Fomes fomentarius extract was effective in suppressing muscle atropy and increasing muscle, which was confirmed through animal behavior evaluation and muscle-related protein expression.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 1999.05a
• /
• pp.33-38
• /
• 1999

Muscle based face image synthesis is one of the most realistic approach to realize life-like agent in computer. Facial muscle model is composed of facial tissue elements and muscles. In this model, forces are calculated effecting facial tissue element by contraction of each muscle strength, so the combination of each muscle parameter decide a specific facial expression. Now each muscle parameter is decided on trial and error procedure comparing the sample photograph and generated image using our Muscle-Editor to generate a specific race image. In this paper, we propose the strategy of automatic estimation of facial muscle parameters from 2D marker movement using neural network. This also 3D motion estimation from 2D point or flow information in captered image under restriction of physics based fare model.

• Journal of Korean Academy of Nursing
• /
• v.34 no.1
• /
• pp.150-159
• /
• 2004

Purpose: The purpose of this study was to determine the effect of DHEA on hindlimb muscles(soleus, plantaris and gastrocnemius) in a focal brain ischemia model rat. Method: Twenty-seven male Sprague-Dawley rats were randomly divided into three groups: CINS(cerebral ischemia + normal saline), CIDH(cerebral ischemia + DHEA), or SHNS(sham + normal saline). Both the CINS and CIDH groups underwent a transient right middle cerebral artery occlusion operation. In the SHNS group, a sham operation was done. 0.34mmol/kg DHEA was administered daily by an intraperitoneal injection for 7days. Results: The muscle weight, muscle fiber cross-sectional area of the Type I muscle fiber of soleus and Type II muscle fiber of plantaris and gastrocnemius, myofibrillar protein content of gastrocnemius, and muscle strength in the CINS group decreased compared with the SHNS group. The muscle weight, muscle fiber cross-sectional area of the Type II muscle fiber of plantaris and gastrocnemius, myofibrillar protein content of soleus, and muscle strength in the CIDH group increased compared with the CINS group. Conclusion: It was identified that muscle atrophy could be induced during 7 days after a cerebral infarction, and DHEA administration during the early stages of a cerebral infarction might attenuate muscle atrophy.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.1566-1571
• /
• 2003

PGO(Powered Gait Orthosis) mounted with pneumatic muscle as an actuator is upgraded model from RGO(Replicate Gait Orthosis) for paraplegia patients to walk easy and safe. Pneumatic muscles supply powers to both hip joint during PGO gait. The objective of this research is to develop the PGO gait simulation model. Dynamic model of PGO linkage system is processed. Mathematical model of pneumatic muscle was developed and combined it with PGO linkage system. Developed simulation model will be used as a tool for evaluation of the efficiency of pneumatic muscle and for analysis the PGO system.

• Journal of the Korean Society for Precision Engineering
• /
• v.30 no.6
• /
• pp.650-657
• /
• 2013

This study uses a muscle activation sensor and elbow joint model to develop an estimation algorithm for human elbow joint torque for use in a human-robot interface. A modular-type MVS (Muscle Volume Sensor) and calibration algorithm are developed to measure the muscle activation signal, which is represented through the normalization of the calibrated signal of the MVS. A Hill-type model is applied to the muscle activation signal and the kinematic model of the muscle can be used to estimate the joint torques. Experiments were performed to evaluate the performance of the proposed algorithm by isotonic contraction motion using the KIN-COM$^{(R)}$ equipment at 5, 10, and 15Nm. The algorithm and its feasibility for use as a human-robot interface are verified by comparing the joint load condition and the torque estimated by the algorithm.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.52 no.9
• /
• pp.560-567
• /
• 2003

EMG recordings of the electrical activity of muscle have proved to be a valuable tool in studying muscle function and reflex activity. SP(silent period) is elicited by a electrical stimulation on the chin during isometric contraction of jaw muscle. This paper proposes a model of the inhibitory reflex mechanism of jaw muscle after electrical stimulation. The SPs of jaw muscle after a electrical stimulation to the chin were divided into SP1 and SP2. SP1 is produced by the activation of periodontal receptors. The activation of nociceptors contributes to the SP2. As a result, the EMG signal generated by a proposed a model of inhibitory reflex mechanism is similar to real both EMG signal including SP1 and SP2. The present study have shown differences of SP1 and SP2 induced by inhibitory reflex mechanism.

• The Korea Journal of Herbology
• /
• v.38 no.5
• /
• pp.31-37
• /
• 2023

Objective : This study was conducted to investigate the muscle-improving and therapeutic effects of Boehmeria platanifolia (BP) in a mouse model of dexamethasone-induced muscle atrophy. Methods : Muscle atrophy was induced in C57BL/6 mice by intraperitoneal administration of dexamethasone for 12 days. BP extract was administered orally at doses of 100 mg/kg and 200 mg/kg for 19 days, starting 7 days before the intraperitoneal administration of dexamethasone. Mice were weighed during the experimental period, and muscle strength and muscle weight were measured at the end of the experiment. The gastrocnemius (GASTROC) muscles of mice were isolated and the cross-sectional area (CSA) of the muscle fibers was measured after H&E staining. Results : Dexamethasone-induced muscle atrophy mice had a decrease in body weight compared to normal mice, and BP-administrated mice did not show significant change in body weight compared with a control group. Muscle strength in mice with induced muscle atrophy was reduced compared to normal and significantly increased with BP administration and positive control. In addition, the weight of the quadriceps (QUAD) muscle and fiber size of the GASTROC muscle, which was reduced in sarcopenia-induced mice, was increased by BP. Conclusion : BP extract increased muscle strength, muscle weight, and muscle fiber size in dexamethasone-induced muscle atrophy mice. This suggests that the efficacy of BP extracts in improving muscle strength and preventing and treating sarcopenia may be beneficial for the development of potential therapeutic or functional products.

• Proceedings of the KSME Conference
• /
• 2000.04a
• /
• pp.261-267
• /
• 2000

A mathematical model was developed to calculate the muscle force of lower extremity during the gait. We constructed a model of human locomotion, which includes a muscle-skeletal system with 7 segments and 16 lower limb muscles. Using a optimization technique, muscle forces variation of the lower extremity during the gait were generated and its result was verified by comparing a experimental results of EMG analysis. Moreover. the walking movement of the model could be compared quantitatively with those of experimental studies in human by inverse dynamics.

• Proceedings of the KIEE Conference
• /
• 1998.07b
• /
• pp.611-613
• /
• 1998

A structure of musculotendon model with a fatigue profile is investigated. The Hill-type musculotendon model can predicts the decline in muscle force for a given fatigue profile. It consists of nonlinear activation and contraction dynamics based on the physiological concepts. It is normalized for generalization to deal with the various muscles. Muscle force generated by continuous tetanic electrical monophasic pulsewidth modulation stimulation is decreased in time. A fatigue profile is expressed by a function of intramuscular acidification and applied to the relationship between muscle force and shortening velocity in contraction dynamics. The results of computer simulation are well matched with data in a literature which are isometrically performed for knee extension muscles. Also change in optimal fiber length has an effect only on muscle time, constant not on the steady-state tetanic force.