• Journal of Physiology & Pathology in Korean Medicine
• /
• v.17 no.6
• /
• pp.1463-1467
• /
• 2003

In the present study, the effects of Ginseng radix and Ophiopogonis tuber on field potentials in rat hippocampal slices and cardiac muscle slices were investigated by multi-channel extracellular recording using MED64 system. The field potentials in the brain slices represent synaptic transmission and nerve excitability, and the field potentials in heart muscles represent muscle contractility. The present results show that the aqueous extract of Ginseng radix enhanced field potentials in the both hippocampal slices and cardiac muscle slices. In contrast, the aqueous extract Ophiopogonis tuber exerted no significant effect on the field potentials in the hippocampal slices and cardiac muscle slices. These results suggest the possibility that Yin-Yang theory could be studied in relation with excitability in neurons and muscles.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.37 no.5
• /
• pp.56-62
• /
• 2000

In this paper, an automatic extraction of the blood flow contour from cardiac MRI is proposed. By using the GVF snake which has wider capture range than the conventional snake, and by automatically generating the initial points along the outside of the contour of the zero GVF field in the edge image of the cardiac MRI, the blood flow contour can be automatically extracted, even when the contours have boundary concavities due to the papillary muscles, without any manual initialization of the experts. Experiments are conducted on the various real cardiac MRIs including noise and papillary muscles, and the proposed method is proved to be efficient in automatic extraction of the blood contours even if they have the boundary concavities.

• Journal of Veterinary Clinics
• /
• v.17 no.1
• /
• pp.70-75
• /
• 2000

This study was undertaken to find out the effect of lead on histopathological changes in rat. Thirty female Wistar rats, 7 weeks old, were divided into a control and two experimental groups. The control was received normal diet. The two experimental groups were received diets contaminated artificially with 10 or 5,000 ug/g of lead administration group, histopathological changes were observed in the kidney, liver, heat, brain and lung from the 4th week of experiment. Desquamation of renal epithelia and inclusion bodies in the epithelia of renal tubules were demonstrated in the kidneys. But the liver did not show acid-fast inclusion body. Degeneration of cardiac muscles were seen. The number of mast cells were increased in the cardiac muscles. Darkly stained neurons in the cerebral cortex, some inflammatory cells around meningeal vessels and distended Virchow-Robin spaces were observed.

• The Korean Journal of Physiology
• /
• v.21 no.2
• /
• pp.179-189
• /
• 1987

Since it has been known that ryanodine has a potent negative inotropic effect on the cardiac muscle contractility (Jenden and Fairhurst, 1968), ryanodine has been a subject of intensive research (Frank and Sleator, 1975; Jones et al, 1978; Sutko et al, 1985). However, the underlying mechanism for the ryanodine dependent negative inotropic effect is still uncertain. In this study, the effects of ryanodine on the generation and relaxation of contracture due to Na-withdrawal and on the force-frequency relationship of heart muscles isolated from rats and guinea pigs were measured in an effort to understand the underlying mechanism of the ryanodine-induced negative inotropy. Results are summerized as follows: 1 ) Ryanodine significantly reduced the contractility of heart muscles produced at low frequency of stimulation, but showed a little effect on the contractility at high frequency stimulation. 2) Ryanodine, at the concentrations ranging from $10^{-6}\;M$ to $10^{-8}\;M$, had no significant effect on the Na-dependent relaxation of Na-withdrawl contracture. 3) Ryandoine significantly reduced the amplitude of the Na-withdrawl contracture, and this inhibitory effect was reinforced by procaine, antiagonized by caffeine and high potassium. From these results, it may be concluded that the negative inotropic effect of ryanodine is mainly due to an inhibition of calcium release from sarcoplasmic reticulum.

• Applied Microscopy
• /
• v.50
• /
• pp.9.1-9.8
• /
• 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.

• Journal of Chest Surgery
• /
• v.16 no.3
• /
• pp.272-280
• /
• 1983

With respect to controversial opinions concerning the nitroglycerin effects on cardiac muscle the direct nitroglycerin actions were thoroughly studied in isolated papillary muscles, atrial preparations and coronary strips of rabbits. Isometric active tension of papillary muscles developed at $35^{\circ}C$ upon electric stimulation at a rate of 60/min, was not affected by nitroglycerin up to a concentration of 10mg/L Higher concentrations of nitroglycerin, however, reduced action tension progressively. This depression of mechanical activity is accompanied by a decrease in oxygen consumption as measured by means of a flow respirometer. Resting oxygen uptake, on the other hand, remained unchanged. Similarly active tension of spontaneously beating atrial preparations also declined at a nitroglycerin concentration of more than 10 mg/L, whereas the sinus frequency did not change up to 40 mg/L. In contrast, rabbit coronary strips are much more sensitive to nitroglycerin and relax in a range of 10-100 ug/L of nitroglycerin concentration. The results indicate that the pharmacologic effects of nitroglycerin in coronary disease are due to vascular actions, because the plasma levels of nitroglycerin attainable in human therapy are not sufficiently high to directly influence the myocardium.

• Korean Journal of Exercise Nutrition
• /
• v.13 no.1
• /
• pp.15-21
• /
• 2009

Ergogenic aids are substances, devices, and practices that enhance an individual's energy use and production, and recovery from fatigue. L-carnitine increases enhance performance and aerobic capacity by stimulating lipid oxidation in muscle cells during long term exercise. L-carnitine is a well known and widely used ergogenic aid. In the present study, the effect of L-carnitine at concentrations of 100 nM, 1 μM, 10 μM, and 100 μM on the amplitude of field potential in rat cardiac muscle slices was measured using multi-channel extracellular recording (MED 64) system. In the present result, L-carnitine was shown to enhance field potential as a does-dependent manner. The increasing effect of the L-carnitine on field potential was not affected by application of the glibenclamide, an ATP-dependant K⁺ channel antagonist. The increasing effect of L-carnitine on field potential was suppressed by application of the diazoxide, an ATP-dependent K⁺ channel agonist. Present data show that L-carnitine potentiates field potentials by inhibition on ATP-dependant K⁺ channel in cardiac muscles. The enhancing effect of the L-carnitine on the field potential in cardiac muscles can be suggested as one of the underlying mechanism of ergogenic aid of the L-carnitine.

• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.8
• /
• pp.1297-1304
• /
• 2007

We conducted a series of investigations in order to elucidate role of nutritional status in regulating GLUT expression and energy metabolism in porcine muscle. Firstly, the role of mild undernutrition in regulating muscle GLUT gene expression and function was studied in growing pigs (3 wk of age) on a high (H) or low (L) food intake (H = 2L) at $35^{\circ}C$ or $26^{\circ}C$. Low food intake selectively upregulates GLUT1 and GLUT4 gene expression; mRNA levels were elevated in longissimus dorsi (L. dorsi) and rhomboideus muscles but not in diaphragm or cardiac muscles. Our next step was to determine whether dietary lysine, a major primary limiting amino acid in diets for pigs, affects muscle GLUT4 expression. Pigs of 6 wk of age were pair-fed a control or low lysine (LL) diet. The control diet contained optimal amounts of all essential amino acids, including 1.15% lysine. The LL diet was similar but contained only 0.70% lysine. GLUT4 mRNA expression was upregulated by the LL diet in L. dorsi and rhomboideus muscles, whereas that in cardiac muscle was unaffected. GLUT4 protein abundance was also higher in rhomboideus muscle of animals on the LL diet. We conducted another investigation in order to elucidate effects of the LL diet on post-GLUT4 glucose metabolism. Activity of hexokinase was unaffected by dietary lysine levels while that of citrate synthase was higher both in L. dorsi and rhomboideus muscles of pigs fed on the LL diet. Glucose 6-phosphate content was higher in L. dorsi msucle in the LL group. Glycogen content was higher both in L. dorsi and rhomboideus muscles in the LL group. Further, we determined the effects of dietary lysine levels on accumulation of intramuscular fat (IMF) in L. dorsi muscle of finishing pigs. A low lysine diet (lysine content was 0.40%) meeting approximately 70% of the requirement of lysine was given to finishing pigs for two months. IMF contents in L. dorsi of the pigs given the low lysine diet were twice higher than those of the pigs fed on a control diet (lysine content was 0.65%). Finally, we proved that a well known effect of breadcrumbs feeding to enhance IMF of finishing pigs could be attributed to shortage of amino acids in diets including breadcrumbs.

• Journal of the Korea Society of Computer and Information
• /
• v.24 no.2
• /
• pp.157-161
• /
• 2019

In this paper, the researcher investigated whether strengthening the back muscles affects the quality of chest compressions during cardiopulmonary resuscitation by university students. A total of 50 students majoring in healthcare were included from September 2018 to November. The participants performed chest compressions during cardiopulmonary resuscitation (CPR) for 2 min after back muscle strength was measured. Then, after adequate rest, the participants repeated the back muscle strength measurements and chest compressions after taping the erector spinae muscle. The paired t-test was performed to analyze changes in chest compression quality after taping. As results, taping enhanced back muscle strength and positively affected the depth of chest compressions and the compression to recoil ratio. Taping also increased confidence and lowered fatigability during chest compressions, so the participants preferred being taped while performing chest compressions. Based on these results, taping could help emergency room medical personnel specialized in CPR to enhance the quality of CPR and relieve back pain and fatigability by strengthening the back muscles.

• Proceedings of the Korean Biophysical Society Conference
• /
• 2001.06a
• /
• pp.61-61
• /
• 2001

Triadin is a ryanodine receptor and calsequestrin binding protein located in junctional sarcoplasmic reticulum of striated muscles. In the present study, mouse cardiac triadin cDNAs have been identified by cDNA library screening and RT-PCR. The deduced aa sequences show that the three isoforms consist of 277, 293 and 305 aa giving rise to the molecular weights of approximately 31,414,33,066, and 34,328 respectively.(omtted)