• The Journal of Advanced Prosthodontics
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• 제9권5호
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• pp.371-380
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• 2017

PURPOSE. The aim of this study is to evaluate and compare the stress distribution in Locator attachments in mandibular two-implant overdentures according to implant locations and different loading conditions. MATERIALS AND METHODS. Four three-dimensional finite element models were created, simulating two osseointegrated implants in the mandible to support two Locator attachments and an overdenture. The models simulated an overdenture with implants located in the position of the level of lateral incisors, canines, second premolars, and crossed implant. A 150 N vertical unilateral and bilateral load was applied at different locations and 40 N was also applied when combined with anterior load at the midline. Data for von Mises stresses in the abutment (matrix) of the attachment and the plastic insert (patrix) of the attachment were produced numerically, color-coded, and compared between the models for attachments and loading conditions. RESULTS. Regardless of the load, the greatest stress values were recorded in the overdenture attachments with implants at lateral incisor locations. In all models and load conditions, the attachment abutment (matrix) withstood a much greater stress than the insert plastic (patrix). Regardless of the model, when a unilateral load was applied, the load side Locator attachments recorded a much higher stress compared to the contralateral side. However, with load bilateral posterior alone or combined at midline load, the stress distribution was more symmetrical. The stress is distributed primarily in the occlusal and lateral surface of the insert plastic patrix and threadless area of the abutment (matrix). CONCLUSION. The overdenture model with lateral incisor level implants is the worst design in terms of biomechanical environment for the attachment components. The bilateral load in general favors a more uniform stress distribution in both attachments compared to a much greater stress registered with unilateral load in the load side attachments. Regardless of the implant positions and the occlusal load application site, the stress transferred to the insert plastic is much lower than that registered in the abutment.

• 대한소아치과학회지
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• 제32권1호
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• pp.101-108
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• 2005

혼합 치열기에서 유치의 탈락 및 영구치의 맹출 과정이 순조롭게 이루어지는 것은 중요한 일이다. 맹출 중인 치아는 인접치 유무, 유치의 흡수속도, 유치의 조기상실, 만기잔존, 국소병소나 입술, 혀, 저작근 등의 다양한 요인들에 의해 영향 받을 수 있으며, 이러한 요소들 사이의 균형이 깨지게 되면 인접치 간의 관계가 변하고 심각한 부정교합이 초래될 수 있다. 본 증례는 유치열 및 혼합치열을 가진 어린이들에서 상하악 구치부 교합면에 접착된 교합 거상 금속 스플린트(bite raising metal splint)가 치열에 미친 영향에 대해 보여주고 있다. 이들은 스플린트로 인한 유치의 만기잔존으로 영구치 맹출에 방해를 받거나, 전치부 개방교합, 제 1대구치의 저위 맹출 등 혼합 치열기 발달에 큰 영향을 받고 있었다. 치료로써 고속 핸드피스를 이용하여 스플린트를 제거하고 주기적 점검을 통해 교합변화 및 영구치 맹출 양상을 관찰하였다.

• 대한한의학회지
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• 제23권3호
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• pp.134-144
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• 2002

Objective : The purpose of this study was to investigate the effect of Jukryuk and Saengkang-juices on cerebral vascular ischemia (CVI) of the middle cerebral artery (MCA). Method : By admiuistration Jukryuk and Saengkang-juices, we compared treated groups with untreated groups, in view of five points as follows: 1) cerebral damage; 2) damaged area of ischemia; 3) cerebral edema; 4) the number of neuronal cells adjacent to the areas damaged by ischemia; and 5) the number of neuronal cells adjacent to the areas damaged by ischemia Results : In this experiment, the effect of Jukryuk and Saengkang-juices was determined by inducing cerebral vascular ischemia after occluding the middle cerebral artery (MCA) in mice, and making observations and comparisons such as alterations in damaged areas and neuronal cellular changes in the brain. Conclusions : According to the above results, Jukryuk and Saengkang-juices can protect the cerebral vascular ischemia.

• Biomolecules & Therapeutics
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• 제7권3호
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• pp.234-241
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• 1999

The present study assessed the cerebroprotective effect of platelet-activating factor(PAF) antagonists in transient cerebral ischemia of rats. Right middle cerebral artery (MCA) of Sprague-Dawley rats was occluded for 2 hours using an intraluminal filament technique, and was reperfused for 6 hours following cerebral ischemia. The infarct area of seven coronal brain slices was measured morphometrically following stain ing in the 2% 2,3,5-triphenyltetrazolium chloride solution. The changes in regional cerebral blood flow (rCBF) and pial arteriolar diameter were measured by laser-Doppler flowmetry and by a videomicroscopy, respectively. The infarct size was significantly reduced by PAF antagonists, BN 52021 and CV-6209, which were administered i.p. 10 min before MCA occlusion. Pretreatment with PAF antagonists significantly restored the changes in pial arterial diameter as well as those in rCBF during the period of cerebral ischemia-reperfusion. PAF antagonists significantly inhibited the inducible nitric oxide synthase activity in the pial arteries ipsilateral to ischemia. These results suggest that PAF antagonists exert a cerebroprotective effect against ischemic brain damage through an improvement of postocclusive cerebral blood flow.

• The Korean Journal of Physiology and Pharmacology
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• 제17권6호
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• pp.485-491
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• 2013

The present study was designed to investigate the putative effect of neurosteroid modulation on global ischaemia-reperfusion-induced cerebral injury in mice. Bilateral carotid artery occlusion followed by reperfusion, produced a significant rise in cerebral infarct size along with impairment of grip strength and motor coordination in Swiss albino mice. Administration of carbamazepine (16 mg/kg, i.p.) before global cerebral ischaemia significantly attenuated cerebral infarct size and improved the motor performance. However, administration of indomethacin (100 mg/kg, i.p.) attenuated the neuroprotective effect of carbamazepine. Mexiletine (50 mg/kg, i.p.) did not produce significant neuroprotective effect. It may be concluded that the neuroprotective effect of carbamazepine may be due to increase in synthesis of neurosteroids perhaps by activating enzyme ($3{\alpha}$ HSD) as indomethacin attenuated the neuroprotective effect of carbamazepine. The sodium channel blocking effect of carbamazepine may not be involved in neuroprotection as mexiletine, a sodium channel blocker, did not produce significant neuroprotective effect.

• 동의생리병리학회지
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• 제17권1호
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• pp.64-70
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• 2003

Jaeumgenby-tang(JGT) have been used in oriental medicine for many centuries as a therapeutic agent of vertigo caused by deficiency of qi(氣) and blood(血). Effect of Aurantii Fructus(AF) take off the phlegm by promoting the circulation of qi, Gastrodae Rhizoma(GR) has effects treating for headache, vertigo by calming the liver and suppressing hyperactivity of the liver-yang(陽). And, I designed to investigate whether injection of JGT adding AFㆍGR extract(JGTAG) affects cytotoxicity in vitro, cerebral hemodynamics [regional cerebral blood flow(rCBF), pial arterial diameter(PAD), mean arterial blood pressure(MABP)] in normal and cerebral ischemia rats by MCA occlusion method. The changes of rCBF and MABP were determinated by laser-doppler flowmetry(LDF), and the change of PAD was determinated by video microscope and width analyzer. The results were as follows in normal rats; JGTAG was not cytotoxicity in brain cells. And JGTAG was significantly increased rCBF, PAD and MABP. This results suggest that JGTAG increased significantly rCBF by dilating PAD. And the results were as follows in cerebral ischemic rats; The changes of rCBF and PAD were increased stably by treatment with JGTAG(10mg/kg, i.v.) during the period of cerebral reperfusion, and pretreatment with propranolol and indomethacin were increased JGT AG induced increase of rCBF and PAD during the period of cerebral reperfusion. We suggest that JGTAG has an anti-ischemic effect through the improvement of cerebral hemodynamics.

• The Korean Journal of Physiology
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• 제9권2호
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• pp.23-31
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• 1975

The effects of ethanol intravenously administered on the mean arterial blood pressure and heart rate responses to electrical stimulation of vagus nerve and the hypothalamus were studied in the cats. Also investigated were the effects of ethanol on the cardiovascular responses to bilateral carotid occlusion and to intravenously injected epinephrine and acetylcholine separately. The results obtained from the present study were as follows; 1. In 1.0 ml/kg and 2.0 ml/kg of ethanol infused groups the mean arterial blood pressure increased gradually and reached plateaus in 10 minutes after ethanol infusion while no marked changes in blood pressure were observed in 0.5 ml/kg of ethanol infused group. 2. The pressor responses elicited by the electrical stimulation of the hypothalamus were depressed directly proportionally to amount of ethanol infused. In 0.5 ml/kg of ethanol infused group the pressor response was reduced to 84.5% of control value and it declined to 17.0% of control in 2.0 ml/kg of ethanol infused group. 3. After ethanol administration the heart rate decreased slightly and also was decreased positive chronotropic effect elicited by hypothalamic stimulation. In several cases even negative chronotropic responses were observed during electrical stimulation in the hypothalamus. 4. Since the pressor responses to bilateral carotid occlusion was reduced by ethanol administration it is suggested that activity of baroreceptor is inhibited by ethanol. 5. No changes were observed in the negative chronotropic effect Produced by electrical stimulation of the vegus nerve of ethanol infused animal. And cardiovascular responses to intravenously injected epinephrine and acetylcholine were not influenced by ethanol either.

• Journal of Korean Neurosurgical Society
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• 제49권1호
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• pp.1-7
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• 2011

Objective: Glutamate is a key excitatory neurotransmitter in the brain, and its excessive release plays a key role in the development of neuronal injury. In order to define the effect of nimodipine on glutamate release, we monitored extracellular glutamate release in real-time in a global ischemia rat model with eleven vessel occlusion. Methods: Twelve rats were randomly divided into two groups: the ischemia group and the nimodipine treatment group. The changes of extracellular glutamate level were measured using microdialysis amperometric biosensor, in coincident with cerebral blood flow (CBF) and electroencephalogram. Nimodipine (0.025 ${\mu}g$/100 gm/min) was infused into lateral to the CBF probe, during the ischemic period. Also, we performed Nissl staining method to assess the neuroprotective effect of nimodipine. Results: During the ischemic period, the mean maximum change in glutamate concentration was $133.22{\pm}2.57\;{\mu}M$ in the ischemia group and $75.42{\pm}4.22\;{\mu}M$ (p<0.001) in the group treated with nimodipine. The total amount of glutamate released was significantly different (P<0.001) between groups during the ischemic period. The %cell viability in hippocampus was $47.50{\pm}5.64$ (p<0.005) in ischemia group, compared with sham group. But, the %cell viability in nimodipine treatment group was $95.46{\pm}6.60$ in hippocampus (p<0.005). Conclusion: From the real-time monitoring and Nissl staining results, we suggest that the nimodipine treatment is responsible for the protection of the neuronal cell death through the suppression of extracellular glutamate release in the 11-VO global ischemia model of rat.

• Asian Pacific Journal of Cancer Prevention
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• 제15권21호
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• pp.9391-9394
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• 2014

Purpose: To evaluate the effect of internal-external percutaneous transhepatic biliary drainage (IEPTBD) for patients with malignant obstructive jaundice. Methods: During the period of January 2008 and July 2013, internal-external drainage was performed in 42 patients with malignant obstructive jaundice. During the procedure, if the guide wire could pass through the occlusion and into the duodenum, IEPTBD was performed. External drainage biliary catheter was placed if the occlusion was not crossed. Newly onset of infection, degree of bilirubin decrease and the survival time of patients were selected as parameters to evaluate the effect of IEPTBD. Results: Twenty newly onset of infection were recorded after procedure and new infectious rate was 47.6%. Sixteen patients with infection (3 before, 13 after drainage) were uncontrolled after procedure, 12 of them (3 before, 9 after drainage) died within 1 month. The mean TBIL levels declined from 299.53 umol/L before drainage to 257.62 umol/L after drainage, while uninfected group decline from 274.86 umol/L to 132.34 umol/Lp (P < 0.5). The median survival time for uninfected group was 107 days, and for infection group was 43 days (P < 0.05). Conclusions: The IEPTBD drainage may increase the chance of biliary infection, reduce bile drainage efficiency and decrease the long-term prognosis, and the external drainage is a better choice for patients with malignant obstructive jaundice need to biliary drainage.

• 대한치과보철학회지
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• 제32권3호
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• pp.431-443
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• 1994

As the dental arch is the curve connecting the cusp tip of tooth, the dental arch form, composing of the occlusion, is one the important factors of occlusal reconstruction. Many studies about the horizontal dental arch form have been reported, but until now, it is unclear to infer the position of the teeth in dental arch form, to evaluate the effect of the horizontal dental arch form on chewing movement. The purpose of this study is to make objective criteria to infer the position of the teeth in dental arch. In this study, 100 subjects with individdual normal occlusion were evaluated. By multiple regression analysis on the basis of the relation of the canine and the first molar, the positions of teeth in dental arch were inferred. According to buccolingual relationship of maxillary to mandibular posterior teeth, the dental arch forms were classified into five groups, i, e. the normal group, the group which the maxillary second molar positions buccal side, the group which the maxillary premolars position buccal side, the group which the maxillary premolar position lingual side. From the results, objective criterial to infer the positons of the first premolar, the second premolar, the second molar in dental arch were made.