• 폴리머
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• 제34권3호
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• pp.185-190
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• 2010

전기방사공정에 의해 고분자의 나노 크기의 섬유를 만드는 기술로 널리 사용되어졌으며, 제작된 나노섬유는 그 높은 표면적과 형태학적 특성때문에 조직재생 공학분야에서 많이 사용되어져 왔다. 본 연구에서는 기존의 전기방사공정을 개선한 복합전기장을 이용하여 생분해성/생체적합성 poly(${\varepsilon}$-caprolactone) (PCL) 마이크로/나노섬유를 제작하였고, 기존의 나노섬유의 배열성보다 제어가 가능한 배열성을 갖는 공정시스템을 통하여 보다 우수한 배열성을 갖는 PCL 나노섬유를 제작하였다. 고배열된 PCL 나노섬유는 신경세포 재생을 위한 세포담체로서의 가능성을 확인하고자 신경세포(PC-12)를 배양하였으며 그 결과 높은 배열성을 갖은 PCL 나노섬유 매트에서 신경세포의 배열성이 얻어짐을 확인하였다.

• The Korean Journal of Physiology
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• 제21권2호
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• pp.313-321
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• 1987

To investigate whether the cervical sympathetics contains specific secretory fibers for the salivary glands, reflex salivation was evoked and the role of the sympathetics or the reflex was examined in ketamine-anesthetized cat. Stimulation of the central end of the glossopharyngeal nerve produced a copious secretion from the submaxillary gland and the response was not affected by the section of the cervical sympathetics or by the administration of phenoxybenzamine, whereas the response was abolished by severing the chorda tympani or by the administration of atropine. The salivary response was always associated with an increase in glandular blood flow. Both salivary and blood flow responses were decreased markedly by the superimposed stimulation of the cervical sympathetics or by the administration of norepinephrine. The decreased submaxillary blood flow always preceded the decrease in salivary flow on stimulation of the cervical sympathetics and the decreased blood flow recovered prior to the salivary flow upon cessation of the sympathetic stimulation. The inhibitory effects of the sympathetics and norepinephrine were completely abolished by the pretreatment with phenoxybenzamine. These results indicate that the glossopharyngeal nerve is one of the afferent limbs of the submaxillary salivary reflex and the chorda tympani is the only efferent limb of the reflex pathway. Thus, it is suggested that the cervical sympathetics does not contain the specific secretory fibers for the gland, but plays a role in inhibiting the reflex secretion by decreasing the blood flow to the gland.

• Clinical Pain
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• 제19권2호
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• pp.80-89
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• 2020

Objective: We compared the regenerative effects of microcurrent therapy (MT) according to the type of electric current, which were direct current microcurrent therapy (DCMT) and alternating current microcurrent therapy (ACMT) on atrophied calf muscle in cast-immobilized rabbit. Method: Rabbits were allocated into control group (sham MT), ACMT group, and DCMT group. Before starting treatment, right gastrocnemius (GCM) muscle was immobilized by cast for 2 weeks. Compound muscle action potential of tibial nerve in nerve conduction study, circumference of calf muscle using a ruler, and thickness of medial and lateral GCM muscle measured by ultrasound, cross sectional area (CSA), and proliferating cell nuclear antigen (PCNA) ratios (%) of muscle fibers were measured on the immunohistochemical analysis. Results: The mean atrophic changes (%) in right medial and lateral GCM muscle thickness, right calf circumference, and amplitude of CMAP of the right tibial nerve in ACMT group and DCMT group were significantly lower than those in control group, respectively (p<0.05). The mean CSA (μm²) of type I and type II and PCNA ratios (%) of medial and lateral GCM muscle fibers in ACMT group and DCMT group were significantly greater than those in control group, respectively (p<0.05). There were no significant differences between the ACMT group and DCMT group at all parameters. Conclusion: This study demonstrated that ACMT and DCMT showed better regeneration effect than sham MT. Microcurrent may be effective in regeneration of atrophied muscle regardless of the type of current.

• The Korean Journal of Physiology
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• 제29권2호
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• pp.309-321
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• 1995

In the present study, the relationship between the somatosympathetic reflexes and arterial blood pressure responses to electrical stimulation of the peripheral nerve was investigated in cats anesthetized with ${\alpha}-chloralose$. Single sympathetic postganglionic fiber activities were recorded from the hindlimb muscle and skin nerves and also from the cervical and abdominal sympathetic chains. Effects of the morphine on responses of the sympathetic nerve and arterial blood pressure to activation of the peripheral $A{\delta}-$ and C-afferent nerves were analyzed. The following results were obtained. 1) Arterial blood pressure was depressed by peripheral AS-afferent stimulation (A-response) and was elevated during C-afferent activation (C-response). 2) Intravenously administered morphine enhanced the C-response while the A-response decreased insignificantly, Only the C-response was decreased by intrathecal morphine. 3) All the ten recorded cutaneous sympathetic fibers showed periodic discharge pattern similar to respiratory rhythm and five of them also showed cardiac-related rhythm. However, most of the muscular sympathetic fibers had cardiac-related rhythm and only four fibers showed respiratory rhythm. 4) Morphine decreased the sympathetic C-reflex elicited by the peripheral C-afferent activation and the abdominal sympathetic A-reflex was also decreased by morphine. From the above results, it was concluded that supraspinal mechanisms were involved in the enhanced arterial pressor response to peripheral C-afferent activation by intravenous morphine.

• The Korean Journal of Physiology
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• 제25권1호
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• pp.87-99
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• 1991

In order to elucidate whether capsaicin applied topically acts as a pain-producing subastance or as a tastant, neuronal activities of the chorda tympani nerve(CN), lingual nerve(LN), solitary tract nucleus(STN), and trigeminal nucleus(TGN) were recorded while thermal and taste stimuli, and capsaicin were being applied topically, and algesics intra-arterially to the tongue of cats anesthetized with ${\alpha}-chloralsoe$. In addition, the STN neurons were examined after wheat germ agglutinin-horseradish peroxidase(WGA-HRP) was applied to the CN. The CN fibers responded to taste and thermal stimuli, algesics, and capsaicin. Responses to capsaicin were significantly correlated with those to taste and thermal stimuli. The LN fibers mainly responded to mechanical and thermal stimuli, algesics, and capsaicin. Responses to capsaicin were significantly correlated with those to algesics. The STN neurons responded to taste and thermal stiumli, algesics, and capsaicin. Responses to capsaicin were significantly correlated with those to taste and thermal stiumli in somewhat different fashion from those of the CN fibers. The TGN neurons mainly responded to mechanical stimuli, algesics, and capsaicin. Correlations between responses to capsaicin and any others were not significant. After WGA-HRP was applied to the CN, the STN neurons which receive input from the CN were identified largely in the medio-ventral portion to the solitary tract. These results suggest that capsaicin produce taste as well as pain sensation. Sensory information evoked by capsaicin can be conveyed to the STN, especially medio-ventral portion, via the CN as gustatory information on the one hand, and to the STN or TGN via the LN as noxious information on the other. In addiation, the noxious information may be conveyed to the STN via the CN.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제30권1호
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• pp.1-16
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• 2004

The use of artificial nerve conduit containing viable Schwann cells is one of the most promising strategies to repair the peripheral nerve injury. To fabricate an effective nerve conduit whose microstructure and internal environment are more favorable in the nerve regeneration than existing ones, a new three-dimensional Schwann cell culture technique using $Matrigel^{(R)}$. and dorsal root ganglion (DRG) was developed. Nerve conduit of three-dimensionally arranged Schwann cells was fabricated using direct seeding of freshly harvested DRG into a $Matrigel^{(R)}$ filled silicone tube (I.D. 1.98 mm, 14 mm length) and in vitro rafting culture for 2 weeks. The nerve regeneration efficacy of three-dimensionally cultured Schwann cell conduit (3D conduit group, n=6) was assessed using SD rat sciatic nerve defect of 10 mm, and compared with that of silicone conduit filled with $Matrigel^{(R)}$ and Schwann cells prepared from the conventional plain culture method (2D conduit group, n=6). After 12 weeks, sciatic function was evaluated with sciatic function index (SFI) and gait analysis, and histomorphology of nerve conduit and the innervated tissues of sciatic nerve were examined using image analyzer and electromicroscopic methods. The SFI and ankle stance angle (ASA) in the functional evaluation were $-60.1{\pm}13.9$, $37.9^{\circ}{\pm}5.4^{\circ}$ in 3D conduit group (n=5) and $-87.0{\pm}12.9$, $32.2^{\circ}{\pm}4.8^{\circ}$ in 2D conduit group (n=4), respectively. And the myelinated axon was $44.91%{\pm}0.13%$ in 3D conduit group and $13.05%{\pm}1.95%$ in 2D conduit group to the sham group. In the TEM study, 3D conduit group showed more abundant myelinated nerve fibers with well organized and thickened extracellular collagen than 2D conduit group, and gastrocnemius muscle and biceps femoris tendon in 3D conduit group were less atrophied and showed decreased fibrosis with less fatty infiltration than 2D conduit group. In conclusion, new three-dimensional Schwann cell culture technique was established, and nerve conduit fabricated using this technique showed much improved nerve regeneration capacity than the silicone tube filled with $Matrigel^{(R)}$ and Schwann cells prepared from the conventional plain culture method.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제32권4호
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• pp.295-307
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• 2006

Styela clava, called non-native tunicate or sea squirt, is habitat which include bays and harbors in Korea and several sites in the sea faced world. We fabricate cellulose membrane nerve conduit (CMNC) from this native sea squirt skin, and evaluate the capacity of promoting peripheral nerve regeneration in the rat sciatic nerve defect model. After processing the pure cellulose membrane from the sea squirt skin as we already published before, CMNC was designed as a non-tubular sheet with 14 mm length and 4 mm width. Total eleven male Spraque-Dawley rats (12 weeks, weighing 250 to 300g) were divided into sham group (n=2), silicone tube grafted control group (n=3) and experimental group (n=6). Each CMNC grafted nerve was evaluated after 4, 8 and 12 weeks in the experimental group, and after 12 weeks, sciatic function was evaluated with sciatic function index (SFI) and gait analysis, and histomorphology of nerve conduit and the innervated tissues of sciatic nerve were all examined using image analyzer and electromicroscopic methods in the all groups. The regenerated axon and nerve sheath were found only in the inner surface of the CMNC after 4 weeks and became more thicker after 8 and 12 weeks. In the TEM study, CMNC grafted group showed more abundant organized myelinated nerve fibers with thickened extracellular matrix than silicone conduit grafted group after 12 weeks. The sciatic function index (SFI) and ankle stance angle (ASA) in the functional evaluation were $-47.2{\pm}3.9$, $35.5^{\circ}{\pm}4.9^{\circ}$ in CMNC grafted group (n=2) and $-80.4{\pm}7.4$, $29.2^{\circ}{\pm}5.3^{\circ}$ in silicone conduit grafted group (n=3), respectively. And the myelinated axon was 41.59% in CMNC group and 9.51% in silicone conduit group to the sham group. The development of a bioactive CMNC to replace autogenous nerve grafts offers a potential and available approach to improved peripheral nerve regeneration. As we already published before, small peptide fragment derived from the basement membrane matrix proteins of squirt skin, which is a kind of anchoring protein composed of glycocalyx, induced the effective axonal regeneration with rapid growth of Schwann cells beneath the inner surface of CMNC. So the possibilities of clinical application as a peripheral nerve regeneration will be able to be suggested.

• 대한치과마취과학회지
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• 제9권2호
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• pp.108-115
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• 2009

Trauma to any nerve may lead to persistent paresthesia. Trauma to the nerve sheath can be produced by the needle. The patient frequently reports the sensation of an electric shock throughout the distribution of the nerve involved. It is difficult for the type of needle used in dental practice to actually sever a nerve trunk or even its fibers. Trauma to the nerve produced by contact with the needle is all that is needed to produce paresthesia. Hemorrhage into or around the neural sheath is another cause. Bleeding increases pressure on the nerve, leading to paresthesia. Injection of local anesthetic solutions contaminated by alcohol or sterilizing solution near a nerve produces irritation; the resulting edema increases pressure in the region of the nerve, leading to paresthesia. Persistent paresthesia can lead to injury to adjacent tissues. Biting or thermal or chemical insult can occur without a patient's awareness, until the process has progressed to a serious degree. Most paresthesias resolve in approximately 8 weeks without treatment. In most situations paresthesia is only minimal, with the patient retaining most sensory function to the affected area. In these cases there is only a very slight possibility of self injury. But, the patient complaints the discomfort symptoms of paresthesia, such as causalgia, neuralgiaform pain and anesthesia dolorosa. Most paresthesias involve the lingual nerve, with the inferior alveolar nerve a close second. This is the report of a case, that had the persistent paresthesia care on left lingual & buccal shelf regions after the lingual and long buccal nerve block anesthesia.

• Journal of Korean Biological Nursing Science
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• 제4권1호
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• pp.101-112
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• 2002

Peripheral nerve injury results in plastic changes in the dorsal ganglia (DRG) and spinal cord, and is often complicated with neuropathic pain. The mechanisms underlying these changes are not known, but these changes seem to be most likely related to the neurotrophic factors. This study investigated the effects of mechanical peripheral nerve injury on expression of brain-derived neurotrophic factor(BDNF) in the DRG and spinal cord in rats. 1) Bennett model and Chung model groups showed significantly increased percentage of small, medium and large BDNF-immunoreactive neurons in the ipsilateral $L_4$ DRG compared with those in the contralateral side at 1 and 2 weeks of the injury. 2) In the ipsilateral $L_5$ DRG of the Chung model, percentage of medium and large BDNF-immunoreactive neurons increased significantly at 1 week, whereas that of large BDNF-immunoreactive neurons decreased at 2 week when compared with those in the contralateral side. The intensity of immunoreactivity of each neuron was lower in the ipsilateral than in the contralateral DRG. 3) In the spinal cord, the Bennett and Chung model groups showed a markedly increased BDNF-immunoreactivity in axonal fibers of both superficial and deeper laminae. The present study demonstrates that peripheral nerve injury in neuropathic models altered the BDNF expression in the DRG and spinal cord. This may suggest important roles of BDNF in sensory abnormalities after nerve injury and in protecting the large-sized neurons in the damaged DRG.

• 대한수의학회지
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• 제40권1호
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• pp.1-16
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• 2000

Nowadays, mongolian gerbil is notably utilized for the research of brain and water deprivation because of a congenital incomplete willis circle structure in the brain, audiogenic seizure in low noise, and special cholesterol metabolism without water absorption for a long time. In this study, we are intend to identify the morphological changes of the catecholaminergic neuron of brain according to the time lapse in the condition of long term water deprivation. 55 mongolian gerbil were divided 10 groups(control, 1, 2, 3, 4, 5, 10, 15, 20, 42th day water deprivation group), of which each group include 5 mongolian gerbils and 5 normal mongolian gerbils in control group were also used for brain atlas as a control. The brains were observed by the immunohistochemical stain using the TH, DBH and PMNT antibody. The results were as followings; 1. The nerve fibers of the TH-immunoreactive neuron were observed only in the and corpus striatum of the telencephalon. 2. Intensity of the immunostain of the nerve fiber in the cerebral cortex and corpus striatum was decreased gradually day by day after water deprivation. 3. The TH-immunoreactive nerve cells were observed in the paraventricular and periventricular nucleus of the 3rd ventricular in the hypothalamus of mongolian gerbil but the number of nerve cells were decreased from the first day of the water deprivation to the 10th day and increased until the 20th day, after than redecreased from the 20th day by the continuous water deprivation. The number of nerve fibers in this area were increased in the first day, but decreased from the 2nd day of water deprivation. The shape and density of the dopamine secreting cells in the brain of mongolian gerbil by the immunoreactive stain were changed in the continuous water deprivation. In this results, we can conclude that dopamine concerned in the water metabolism of mongolian gerbil, and mongolian gerbil could be used as an animal model for the research of water deprivation.