• 대한약리학회지
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• 제19권1호
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• pp.15-35
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• 1983

Although it has been well known that ventricular fibrillation is the most important complication during hypothermia, much investigation has failed to show the exact nature of the etiology of ventricular fibrillation. Recently, there has been considerable research on the relationship between sympathetic activity and ventricular fibrillation under hypothermia. Cardiac muscle normally contains a certain amount of norepinephrine and the dramatic effect of this catecholamines on the cardiac muscle is well documented. It is, therefore, conceivable that cardiac catecholamines might exert an influence on the susceptibility of heart muscle to tachycardia, ventricular fibrillation and arrhythmia, under hypothermia. Hypothermia itself is stress enough to increase tonus of sympatheticoadrenal system. The normal heart is supplied by an autonomic innervation and is subjected to action of circulating catecholamines which may be released from the heart. If the reaction of the heart associated with a variable amount of cardiac catecholamines is. permitted to occur in the induction of hypothermia, the action of this agent on the heart has not to be differentiated from the direct effects of cooling. The studies presented in this paper were designed to provide further information about the cardio-physiological effects of reduced body temperature, with special reference to the role of catecholamines in ventricular fibrillation. Healthy cats, weighing about 3 kg, were anesthetized with pentobarbital(30 mg/kg) intraperitoneally. The trachea was intubated and the endotracheal tube was connected to a C.F. Palmer type A.C. respirator. Hypothermia was induced by immersing the cat into a ice water tub and the rate of body temperature lowering was $1^{\circ}C$ per 5 to 8 min. Esophageal temperature and ECG (Lead II) were simultaneously monitored. In some cases the blood pH and serum sodium and potassium were estimated before the experiment. After the experiment the animals were killed and the hearts were excised. The catecholamines content of the cardiac muscle was measured by the method of Shore and Olin (1958). The results obtained are summarized as follows. 1) In control animal the heart rate was slowed as the temperature fell and the average pulse rates of eight animals were read 94/min at $31^{\circ}C$, 70/min at $27^{\circ}C$ and 43/min at $23^{\circ}C$ if esophageal temperature. Ventricular fibrillation was occurred with no exception at a mean temperature of $20.3^{\circ}C(21-l9^{\circ}C)$. The electrocardiogram revealed abnormal P waves in each progressive cooling of the heart. there was, ultimately, a marked delay in the P-R interval, QRS complex and Q-T interval. Inversion of the T waves was characteristic of all animals. The catecholamines content of the heart muscle excised immediately after the occurrence of ventricular fibrillation was about thirty percent lower than that of the pre-hypothermic heart, that is, $1.0\;{\mu}g/g$ wet weight compared to the prehypothermic value of $1.41\;{\mu}g/g$ wet weight. The changes of blood pH, serum sodium and potassium concentration were not remarkable. 2) By the adrenergic receptor blocking agent, DCI(2-3 mg/kg), given intramuscularly thirty minutes before hypothermia, ventricular fibrillation did not occur in one of five animals when their body temperature was reduced even to $16^{\circ}C$. These animals succumbed at that low temperature, and the changes of heart rate and loss of myocardial catecholamines after hypothermia were similar to those of normal animals. The actual effect of DCI preventing the ventricular fibrillation is not predictable. 3) Administration of reserpine(1 mg/kg, i.m.) 24 hours Prior to hypothermia disclosed reduced incidence of ventricular fibrillation, that is, six of the nine animals went into fibrillation at an average temperature of $19.6^{\circ}C$. By reserpine myocardial catecholamines content dropped to $0.045\;{\mu}g/g$ wet weight. 4) Bretylium pretreatment(20 mg/kg, i.m.), which blocks the release of catecholamines, Prevented the ventricular fibrillation under hypothermia in four of the eight cats. The pulse rate, however, was approximately the same as control and in some cases was rather slower. 5) Six cats treated with norepinephrine(2 mg/kg, i.m.) or DOPA(50 mg/kg) and tranylcypromine(10 mg/kg), which tab teen proved to cause significant increase in the catecholamines content of the heart muscle, showed ventricular fibrillation in all animals under hypothermia at average temperature of $21.6^{\circ}C$ and the pulse rate increased remarkably as compared with that of normal. Catecholamines content of cardiac muscle of these animals markedly decreased after hypothermia but higher than control animals. 6) The functional refractory periods of isolated rabbit atria, determined by the paired stimulus technique, was markedly shortened by administration of epinephrine, norepinephrine and isoproterenol. 7) Adrenergic beta-blocking agents, such as pronethalol, propranolol and sotalol(MJ-1999), inhibited completely the shortening of refractory period induced by norepinephrine. 8) Pretreatment with either phenoxftenbamine or phentolamine, an adrenergic alphatlocking agent, did not modify the decrease in refractory period induced by norepinephrine. From the above experiment it is possible to conclude that catecholamines play an important role in producing ventricular fibrillation under hypothermia. The shortening of the refractorf period of cardiac muscle induced by catecholamines mar be considered as a partial factor in producing ventriculr fibrillaton and to be mediated by beta-adrenergic receptor.

• Asian-Australasian Journal of Animal Sciences
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• 제19권12호
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• pp.1799-1808
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• 2006

This study was designed to explore the effects of marbling on meat quality characteristics and intramuscular connective tissue of beef longissimus muscle. Chemical determinations, histological and mechanical measurements were performed on the raw and cooked meat at d 4 postmortem. The results showed that crude fat, collagen, fiber diameter and maximum transition temperature of intramuscular connective tissue increased (p<0.05) with the increase of marbling score. The cooking losses, collagen solubility, WBSF and perimysial thickness decreased (p<0.05) with the increasing marbling. WBSF correlated (p<0.05) with moisture, crude fat, collagen, cooking losses, sarcomere length and perimysial thickness. The development of marbling results in the decline in cooking losses, the avoidance of sarcomere shortening, and the disorganization of the perimysia, which accounts for the improvement of beef tenderness.

• The Korean Journal of Physiology
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• 제25권1호
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• pp.17-26
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• 1991

Single smooth muscle cells of the rabbit pulmonary artery were isolated by treatment with collagenase and elastase. Using the patch clamp technique, potassium channel activity was recorded from the inside-out membrane patch. The channel had a sin히e channel conductance of about 360 pS in symmetrical concentration of K on both sides of the patch, 150 mM, and had a linear current-voltage relationship. During the application of 10 mM tetraethylammonium (TEA) to the intracellular membrane surface, the amplitude of single channel current was reduced and very rapid flickering appeared. The open probability $(P_0)$ of this channel was increased by increasing positivity of the potential across the patch membrane, with e-fold increase by 20 mV depolarization, and by increasing the internal $Ca^{2+}$ concentration. These findings are consistent with those of large conductance Ca-activated K channels reported in other tissues. But the shortening of the mean open time by increasing $[Ca^{2+}]_i$, was an unexpected result and one additional closed state which might be arisen from a block of the open channel by Ca binding was suggested. The $P_0-membrane$ potential relationship was modulated by internal pH. Decreasing pH reduced $P_0$. Increasing pH not only increased $P_0$ but also weakened the voltage dependency of the channel opening. The modulation of Ca-activated K channel by pH was thought to be related to the mechanism of regulation of vascular tone by the pH change.

• Archives of Plastic Surgery
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• 제49권5호
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• pp.633-641
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• 2022

Introduction In chronic facial palsy, synkinetic muscle overactivity and shortening causes muscle stiffness resulting in reduced movement and functional activity. This article studies the role of multimodal therapy in improving outcomes. Methods Seventy-five facial palsy patients completed facial rehabilitation before being successfully discharged by the facial therapy team. The cohort was divided into four subgroups depending on the time of initial attendance post-onset. The requirement for facial therapy, chemodenervation, or surgery was assessed with East Grinstead Grade of Stiffness (EGGS). Outcomes were measured using the Facial Grading Scale (FGS), Facial Disability Index, House-Brackmann scores, and the Facial Clinimetric Evaluation scale. Results FGS composite scores significantly improved posttherapy (mean-standard deviation, 60.13 ± 23.24 vs. 79.9 ± 13.01; confidence interval, -24.51 to -14.66, p < 0.0001). Analysis of FGS subsets showed that synkinesis also reduced significantly (p < 0.0001). Increasingly, late clinical presentations were associated with patients requiring longer durations of chemodenervation treatment (p < 0.01), more chemodenervation episodes (p < 0.01), increased doses of botulinum toxin (p < 0.001), and having higher EGGS score (p < 0.001). Conclusions This study shows that multimodal facial rehabilitation in the management of facial palsy is effective, even in patients with chronically neglected synkinesis. In terms of the latency periods between facial palsy onset and treatment initiation, patients presenting later than 2 years were still responsive to multimodal treatment albeit to a lesser extent, which we postulate is due to increasing muscle contracture within their facial muscles.

• 대한치과보철학회지
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• 제40권2호
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• pp.193-200
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• 2002

For the purpose of decreasing the chair time in implant cases, the time needed to loosening and fastening the screw must be shortened. Nowadays, the two typical designs of screw head are slot and hexa form. This study aimed at the shortening of loosening and fastening time by modifying the slot and hexa form. Total of twelve dentists participate in these experiments, four of them were experienced and eight of them were novice dentists. 1. There were many differences in the speeds of screw loosening and fastening between personal experiences. Experienced dentists are faster than novice dentists. 2. There were many differences in the speeds by angulation of the implant, by the conditions of the muscle tonicity. 3. Revised slot and hexa Heads show the slightly shortened time for acrew looseing and fastening.

• 한국임상수의학회지
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• 제17권2호
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• pp.505-509
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• 2000

A five-month old female dog was presented to Teaching Anilmal Hospital, Gyeongasng National University for femur fracture. Previously the dog had been presented to a local hospital. Orthopedic and blood examinations were conducted. There was absent response of conscious propri- oception. The dog stood knuckled onto the digits and had hock dropped, but showed no117a1 values in WBC.RBC, Hb, PCV, BUN, Creatine, Glucose, Cholesterol, AST and ALT. Plain radioaraphs were taken and there were abundant periosteal reaction and malalignment of fragments. The dog was anesthetized and prepared for aseptic surgery. Joshi external fixator and half pins were applied(uni lateral). AT 8 weeks after surgery, the pins were removed from the bone. The fracture was well healed wish no evidence of original fracture line. but mild muscle atropy and shortening of femur were found.

• 한국축산식품학회:학술대회논문집
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• 한국축산식품학회 2000년도 정기총회 및 제25차 춘계학술발표회
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• pp.123-123
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• 2000

• 대한정형도수물리치료학회지
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• 제3권1호
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• pp.29-42
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• 1997

The theory of plyometric exercise was introduced by Soviet Jump Coach Yuri Verhoshanski in 1967. Plyo comes from the Greek word pleythein, which means to increase. Plyo is the Greek word for "more", while metric means "to measure". The practical definition of plyometrics is a quick powerful movement involving a prestretching or countermovement that activates the stretch-shortening cycle. The purpose of plyometric training is to heighten the excitability of the nervous system for improved reactive ability of the neuromuscular system. The success of plyometric exercise is based on the utilization of the serial elastic properties and stretch-reflex properties of the muscle.

• Clinical and Experimental Pediatrics
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• 제55권9호
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• pp.350-353
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• 2012

An 18-year-old boy was admitted with chest discomfort, nausea, and dyspnea at rest. At the age of 3 years, he underwent muscle biopsy and dystrophin gene analysis owing to an enlarged calf muscle and elevated serum kinase level (6,378 U/L) without overt weakness; based on the results, Becker muscular dystrophy (BMD) was diagnosed. The dystrophin gene showed deletion of exons 45 to 49. He remained ambulant and could step upstairs without significant difficulties. A chest roentgenogram showed cardiomegaly (cardiothoracic ratio, 54%), and his electrocardiogram (ECG) showed abnormal ST-T wave, biatrial enlargement, and left ventricular hypertrophy. The 2-dimensional and M-mode ECGs showed a severely dilated left ventricular cavity with diffuse hypokinesis. The systolic indices were reduced, including fractional shortening (9%) and ejection fraction (19%). Despite receiving intensive medical treatment, he died from congestive heart failure 5 months after the initial cardiac symptoms. We report a case of BMD with early-onset dilated cardiomyopathy associated with deletion of exons 45 to 49. Early cardiomyopathy can occur in BMD patients with certain genotypes; therefore, careful follow-up is required even in patients with mild phenotypes of BMD.

• 한국운동역학회지
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• 제14권1호
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• pp.161-172
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• 2004

본 연구의 목적은 각기 다른 수직 점프 동작 시 근육의 길이와 근육의 수축속도 변화를 비교 분석하는데 있다. 피험자의 운동학적 변인들을 분석하기 위해 2대의 고감도 카메라를 (60 Hz, Panasonic AG455) 사용하여 점프 동작을 촬영하였다. 대퇴직근, 내측광근, 외측광근, 중간광근, 대퇴이두근(단두), 내측과 외측 비복근의 길이와 근수축 속도는 Brand et al. (1982)에 의해 제시되어진 하지근 기시 정지점의 3차원 좌표값과 동작분석을 통한 하지 분절간의 회전 및 변환행렬을 사용하여 측정되어졌다. 일반적인 근육 길이와 수축속도의 변화 형태는 각기 다른 점프간에 매우 유사한 형태를 보였다. 상승기 초기에 대퇴사두근의 길이가 최대인것으로 나타났으며, 이에 반해 대퇴이두근과 내외측 비복근은 공중 동작이 발생하는 시점에 근의 길이가 최대인 것으로 나타났다. 근육의 길이 변화 범위는 대퇴직근이 35.9에서 47.5 cm, 외측광근이 29.4에서 38.8 cm, 중간광근이 31.5에서 38.0 cm, 내측광근이 30.9에서 38.6 cm, 대퇴이두근이 21.3에서 39.1 cm, 외측비복근이 31.4에서 33.5 cm, 내측비복근이 30.5에서 33.2 cm인 것으로 나타났다. SQ와 CMJ에서는 대퇴사두근의 최대 단축성 수축 속도와 대퇴이두근과 내외측 비복근의 최대 신장성 수축이 공중동작이 발생하기 바로 전에 이루어졌다. 대퇴사두근의 최대 신장성 수축과 대퇴이두근과 내외측 비복근의 최대 단축성 수축은 일반적으로 피험자가 착지하는 순간에 발생되어졌다. 그러나 HJ와 DJ에서는 대퇴사두근의 최대 신장성 추축과 대퇴이두근과 내외측 비복근의 최대 신장성 수축이 하강기 초반에 발생되어졌다.