• The Korean Journal of Physiology
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• 제30권2호
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• pp.289-297
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• 1996

Excitatory amino acids (EAA) are thought to play an important role in producing cell death associated with ischemic and traumatic spinal cord injury. The present study was carried out to determine if the response characteristics of spinal sensory neurons in segments adjacent to degeneration sites induced by EAA are altered following these morphological changes. Intraspinal injections of quisqualic acid (QA) produced neuronal degeneration and spinal cavitation of gray matter. The severity of lesions was significantly attenuated by pretreatment with a non-NMDA antagonist NBQX. In extracellular single unit recordings, dorsal horn neurons in QA injected animal showed the increased mechanosensitivity, which included a shift to the left in the stimulus-response relationship, an increased background activity and an increase in the duration of after-discharge responses. Neuronal responses, especially the C-fiber response, to suprathreshold electrical stimulation of sciatic nerve also increased in most cases. These results suggest that altered functional states of neurons may be responsible for sensory abnormalities, e.g. allodynia and hyperalgesia, associated with syringomyolia and spinal cord injury.

• The Korean Journal of Pain
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• 제11권2호
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• pp.294-298
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• 1998

The feature of neuropathic pain may occur in the absence of any apparent stimulus and be exaggerated in either amplitude or duration. Peripheral nerve injury may produce neuropathic pain and opioids have been shown to be relatively unsatisfactory for the treatment of most cases of neuropathic pain. The NMDA receptor system is involved in transmission and modulation of nociceptive information. We treated patients with severe pain, hyperaesthesia and allodynia with epidural injection of NMDA receptor antagonist, ketamine (10 mg) and morphine (0.5 mg) or other opioid. The combinations provided effective pain management in 23 patients with neuropathic pain.

• 감성과학
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• 제21권1호
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• pp.115-128
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• 2018

디자인 과정과 실제 공간을 사용함에 있어 공간감을 이해하는 것이 매우 중요한 역할을 하는데, 동일한 공간이라도 어떻게 디자인하느냐에 따라 공간의 깊이감에 대한 지각이 달라질 수 있다. 공간의 3차원적인 속성인 넓이, 깊이, 높이 중 넓이와 높이감에 대한 이론과 연구들에 비해 깊이감에 대한 이론이나 연구는 상대적으로 적은데 이는 넓이나 높이에 비해 공간의 깊이감이 초래하는 효과에 대한 관심이 부족했던 원인으로 보인다. 본 연구는 Computer Graphic으로 제작한 실내공간을 대상으로 시선추적장치를 이용하여 깊이감에 대한 지각과정을 이해하고자 하였다. 44명의 실내디자인 전공 학생들이 실험에 참가하여 마주보이는 벽면에 깊이감을 자극하는 구성요소를 달리한 3개의 이미지를 보며 가장 깊어보이는 공간을 탐색하였다. 그 결과 3개의 이미지간에 주시시간의 차이가 나타났고, 가장 깊어 보이는 공간에 대한 응답에 따라서도 주의집중에 통계적으로 유의미한 차이가 발견되었다. 본 연구는 깊이감에 영향을 끼치는 요인과 기존 정설에 대한 정량적인 타당성을 제시하고, 이상적인 공간의 깊이감을 얻을 수 있는 디자인 방법 개발 등에 도움이 될 것으로 본다.

• The Korean Journal of Physiology
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• 제16권1호
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• pp.13-23
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• 1982

Effects of external pH and potassium concentrations on the electrical and mechanical properties were investigated on rabbit papillary muscle. Papillary muscles were perfused in horizontal chamber with Tris Tyrode solutions and action potential along with isometric tension was recorded simultaneously. Potassium concentrations were varied between 1 and 12 mM at low(6.9), normal(7.4) and high (7.9) external pH. The following results were obtained: 1) On rasing the potassium concentration from 1 to 12 mM resting membrane potentials decreased from $-88.8{\pm}2.8$ to $-66.4{\pm}1.2\;mV$ at normal pH and the amplitude of action potential decreased from $115.1{\pm}0.7$ to $97.5{\pm}2.8\;mV$. On lowering the potassium concentration, membrane hyperpolarized and at 1 mM potassium concentration resting potentials were $-107{\pm}2.2\;mV$. Duration of action potential especially $APD_{60}{\sim}APD_{90}$ increased($APD_{90}$: $214{\pm}15.8\;ms$ at 1 mM $K^+$ to $287{\pm}18.1\;ms$ at 12 mM $K^+$). 2) During acidosis membranes hyperpolarized by more than 20 mV within 1 min. and then slow recovery was observed during the following 10 min. During alkalosis membranes depolarized about 10 mV, which were maintained until washing with normal Tyrode solutions. 3) On lowering the external pH(7.9-6.5), duration of action potential increased progressively and it was most prominent at pH 6.5 and $K^+$ 1mM. 4) Magnitude of developed tension was $0.6{\pm}0.14\;g/mm^2$ at normal pH and potassium concentration (stimulus frequency : 60/min). Relative isometric tension to normal value increased along the increment of stimulus frequency($44.2{\pm}4.2%$ at 6/min to $271{\pm}86.7%$ at 180/min). Force-frequency relations were altered quantitatively during the perfusion with different external pH solutions. 5) Developed tension did not show marked variation within the range of $2{\sim}8\;mM$ potassium concentrations. Positive inotropism was observed at less than 2 mM $K^+$ and negative inotropism beyond 12 mM $K^+$ concentrations. From the above results we concluded that the effects of potassium ion concentration on electrical and mechanical properties of rabbit papillary muscle are related to the changes in surface negative charge due to acid base disturbances.

• The Korean Journal of Physiology and Pharmacology
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• 제11권1호
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• pp.1-7
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• 2007

Altered environmental gravity, including both hypo- and hypergravity, may result in space adaptation syndrome. To explore the characteristics of this adaptive plasticity, the expression of immediate early gene c-fos mRNA in the vestibular related tissues following an exposure to hypergravity stimulus was determined in rats. The animals were subjected to a force of 2 g (twice earth's gravity) for 1, 3, or 12 h, and were examined poststimulus at 0, 2, 6, 12, and 24 h. RT-PCR (reverse transcription polymerase chain reaction) and real-time quantitative RT-PCR were adopted to analyze temporal changes in the expression of c-fos mRNA. The hypergravity stimulus increased the expression of c-fos mRNA in the vestibular ganglion, medial vestibular nucleus, inferior vestibular nucleus, hippocampus, cerebellum, and cortex. The peak expression occurred at 0 h poststimulation in animals stimulated with hypergravity for 1 h, and at 6 h poststimulus in those stimulated for 3 h. In contrast, those stimulated for 12 h exhibited dual peaks at 0 and 12 h poststimulus. Bilateral labyrinthectomy markedly attenuated the degree of c-fos mRNA expression. Glutamate receptor antagonist also dramatically attenuated the degree of c-fos mRNA expression. These results indicate that expression of c-fos mRNA in response to hypergravity occurs in the vestibular related tissues of the central nervous system, in which peripheral vestibular receptors and glutamate receptors play an important role. The temporal pattern of c-fos mRNA expression depended on the duration of the hypergravity stimulus.

• The Korean Journal of Physiology
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• 제17권2호
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• pp.169-176
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• 1983

It is well known that the acupuncture has been used effectively for the relief of certain types of pain. Although the precise mechanism of action of acupuncture analgesia is unknown, it is generally accepted that their analgesic properties are related to the activation of endogenous opiate system in central nervous system. And it is suggested that pain-relieving properties of acupunture may be related to a stimulation of peripheral nerve underlying the acupuncture point on the skin. However, the efficacy of acupuncture has no relationship between the site of pain and the acupuncture point. Consequently, the present study was undertaken to investigate electroacupuncture analgesia in relation to the site of peripheral nerve stimulation. Cats were decerebrated ischemically and the flexion reflex as an index of pain was elicited by stimulating the sural nerve (20V, 0.5 msec duration) and recored as a compound action potential from the nerve innervated to the posterior biceps femoris muscle in the ipsilateral hindlimb. Bilateral common peroneal nerve and contralateral superficial radial nerve were selected as the site of peripheral nerve stimulation. For the stimulation of peripheral nerve, a stimulus of 20 V intensity, 2 msec-duration and 2 Hz-frequency was applied for 60 min respectively. The results obtained are summarized as follows: 1) Both stimulation of contralateral common peronal nerve and contralateral superficial radial nerve did not change the flexion reflex and there were no significant differences between them. 2) Stimulation of ipsilateral common peroneal nerve markedly depress the flexion reflex, the effect being reversed by naloxone application. These results suggest that stimulation of ipsilateral common peroneal nerve has the analgesic effect but both stimulation of contralteral common peroneal nerve and contralateral superficial radial nerve to the pain site where flexion reflex was elicited have no analgesic effect.

• The Korean Journal of Physiology
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• 제15권2호
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• pp.73-81
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• 1981

Experiments were conducted in ischemic decerebrate cats to study the effects of electroacupuncture and electrical stimulation of peripheral nerve on pain reaction. Flexion reflex was used as an index of pain. The reflex was elicited by stimulating the sural nerve(20 V, 0.5 msec duration) and recorded as a compound action potential from the nerve innervated to the semitendinosus muscle. Electroacupuncture was performed, using a 23-gauge hyperdermic needle, on the tsusanli point in the lateral upper tibia of the ipsilateral hindlimb. The common peroneal nerve was selected as a peripheral nerve which may be associated with electroacupuncture action, as it runs through the tissue portion under the tsusanli point. Both for electroacupuncture and the stimulation of common peroneal nerve a stimulus of 20 V-intensity, 2 msec-duration and 2 Hz-frequency was applied for 60 min. The results are summerized as follows: 1) The electroacupuncture markedly depressed the flexion reflex; this effect was eliminated by systemic application of naloxone $(0.02{\sim}0.12\;mg/kg)$, a specific narcotic antagonist. 2) Similarly, the electrical stimulation of the common peroneal nerve significantly depressed the flexion reflex, the effect being reversed by naloxone. 3) When most of the afferent nerves excluding sural nerve in the ipsilateral hindlimb were cut, the effect of electroacupuncture on the flexion reflex was not observed. Whereas direct stimulation of the common peroneal nerve at the proximal end from the cut resulted in a significant reduction of the flexion reflex, again the effect was reversible by naloxone application. 4) Transection of the spinal cord at the thoracic 12 did not eliminate the effect of peripheral nerve stimulation on the flexion reflex and its reversal by naloxone, although the effect was significantly less than that in the animal with spinal cord intact. These results suggest that: 1) the analgesic effect of an electroacupuncture is directly mediated by the nervous system and involves morphine-like substances in CNS, 2) the site of analgesic action of electroacupuncture resides mainly in the brainstem and in part in the spinal cord.

• 한국의학물리학회지:의학물리
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• 제19권1호
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• pp.73-79
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• 2008

망막색소변성(retinitis pigmentosa: RP)과 연령 관련 황반변성(age-related Macular Degeneration: AMD)은 망막변성으로 인해 실명에 이르는 대표적인 질환이며 망막이식장치의 개발을 통해 치료될 수 있다고 간주되고 있다. 최근에 국내에서도 망막이식장치 개발을 위한 연구팀이 조직되었다. 성공적인 망막이식장치 개발을 위하여 여러 가지 선결요소가 필요하지만 그 중 한 가지가 이식장치에 인가할 전기자극을 최적화하는 것이다. 변성망막의 전기적 특성은 정상 망막과 다르리라 예측되므로 우리는 장차 개발될 망막 이식장치에 인가할 전기자극 최적화를 위한 가이드라인을 제공하기 위해 정상 망막과 변성 망막의 전압자극 파라미터에 관한 실험을 하였다 망막을 분리한 후 망막절편을 신경절세포 층이 다채널전극의 표면을 향하게 하여 전극에 붙인다 in-vitro 상태에서 망막 신경절세포의 전기신호를 기록하기 위해 전극 직경: $30{\mu}m$, 전극간 거리: $200{\mu}s$, 전극 임피던스 1kHz 에서 $50k{\Omega}$인 8행 8열의 다채널전극을 사용하였다. 다채널전극의 60채널 중 두 채널을 자극전극과 접지로 사용하여 단극전기자극을 인가하였고 나머지 전극을 기록전극으로 사용하였다. 가한 전기자극은 전압자극으로 전하균형을 맞춘 이상성자극을 아노딕 사각파를 먼저 주고 캐쏘딕 사각파가 나중에 나오는 형태로 두 사각파간의 지체는 없도록 하였으며 동일한 자극을 2초 간격으로 50회 반복하여 인가하였다. 다양한 전기자극을 사용하였는 바 첫째는 사각파의 크기를 달리하였다 $(0.5{\sim}3V)$. 둘째는 사각파의 시간을 달리하였다 $(100{\sim}1,200{\mu}s)$. 전하밀도는 옴의 법칙과 쿨롱의 법칙을 이용하여 계산하였다. 전기자극으로 유발된 반응은 50회 자극에 대한 평균치를 얻은 후 자극 후 히스토그램(PSTH)을 그려 분석하였다. 전압자극의 크기를 $0.5{\mu}3V$로 달리하였을 때 믿을 만한 망막신경절세포가 유발되는 자극은 1.5V이었고 이때 계산된 전하밀도의 역치는 $2.123mC/cm^2$이었다. 전압의 크기를 2V로 고정하고 자극 지속시간을 $100{\sim}1,200{\mu}s$로 달리하였을 때 믿을 만한 망막신경절세포가 유발되는 자극의 역치는 $300{\mu}s$에서 관찰되었다. 이때 계산된 전하밀도의 역치는 $1.698mC/cm^2$이었다. L-(1)-2-amino-4-phosphonobutyric acid (APB)을 사용하여 ON-경로를 차단한 후에 전기자극을 인가하였을 때도 자극에 의해 망막신경절 세포의 반응이 유발되는 것을 확인하였다. APB-변성망막에서 전압의 크기를 2V로 고정하고 자극 지속시간을 $100{\sim}1,200{\mu}s$로 달리하였을 때 믿을 만한 망막신경절세포가 유발되는 자극의 역치는 $300{\mu}s$에서 관찰되었으며 이는 정상망막의 결과와 같았다. 추후 APB-변성망막을 가지고 좀더 실험이 진행되어야 정상망막과 변성망막의 전하밀도에 관한 명료한 비교가 가능할 것이다.

• IMMUNE NETWORK
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• 제5권2호
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• pp.117-123
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• 2005

The immune response to any stimulus is complex, requiring coordinated action by several types of cells in a tightly regulated sequence. Thus, a physical stress such as exercise may act at any number of points in the complex sequence of events collectively termed the immune response. Although exercise causes many propound changes in parameters of immune function, the nature and magnitude of such changes rely on several factors including the immune parameters of interest; type, intensity, and duration of exercise; fitness level or exercise history of the subject; environmental factors such as ambient temperature and humidity. Although regular moderate exercise appears to be important factor for increasing immunity, Athletes are susceptible to illness, in particular upper respiratory track infection, during periods of intense training and after competition. In addition, in elite athletes, frequent illness is associated with overtraining syndrome, a neuroendocrine disorder resulting from excessive training. Through this paper, we want to investigate the effects of exercise on the immunosuppression such as exercise induced lymphopenia, asthma, anaphylaxis, URT (upper respiratory track), and TB (tuberculosis) infection. and also, we want to suggest a direct mechanism, protection and therapy of exercise induced immunosuppression.

• Journal of Oral Medicine and Pain
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• 제8권1호
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• pp.5-31
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• 1983

Author studied the changes of experimental bite marks using a special apparatus which was equipped with adults human resin dental model(in accordance with the time elapsed). The experimental bite marks were made in the forearm of 20 healthy men and in the buttock of 10 Durac pigs with various pressure. In making the experimental bite marks, the left forearm was pressed with a load of 70kgs and 130kgs for 3 seconds, and 5 of the 10 pigs were sacrigiced immediately after making the bite marks. Through visual examinations, photographs and rubber base impressions of bite marks, following results were obtained : 1. The durations of measurable indentation of the experimental bite marks in the forearm of living human subject were depended upon the degree of the pressure and the length of the pressure time applied in making the bite marks. 2. As a physiological responds to a physical stimulus of biting, indentation, bruising, edema and subepithelial bleeding were observed in the experimental bite marks in the forearm of living human. And the experimental bite marks in the buttok of pigs which were sacrificed immediately after making the bite showed only indentation and subepithelial bleeding in addition to postmortem changes. 3. The duration of measurable indentation of the experimental bite marks in the buttock of pigs which were sacrificed immediatly after making the bite were much longer than those of the living pigs. 4. All of the measurements of the experimental bite marks were not matched completly with those of the model which was used in making the bite marks.