침전법에 의한 알루미나 분말제조 IV.ZrO₂의 분산에 의한 Al₂O₃/ZrO₂ 복합체의 제조 및 기계적 특성

홍기곤,이홍림,이형직,이호순 연세대학교 산업기술연구소 1992 논문집 Vol.24 No.2

In this study, a precipitation method, one of the most effective liquid phase reaction, was adopted in order to prepare high-tech Al₂O₃/ZrO₂ composite ceramics. Al₂(SO₄)₃·18H₂O, ZrOCl₂·8H₂O and YCl₃·6H₂O were used as starting materials and NH₄OH as a precipitation agent. Fine powders were prepared at optimum calcination condition. Sinterability of each fine powder and the effects of ZrO₂ on the grain size and mechanical properties of Al₂O₃ were investigated. The composition of Al₂O₃/ZrO₂ composites was fixed as Al₂O₃-15v/o ZrO₂(+3m/o Y₂O₃). The effect of MgO on the grain size of Al₂O₃ZrO₂ ceramics was also investigated.

Fluoxetine이 Schedule-Induced Polydipsia가 유발된 백서 뇌에서 Tyrosine Hydroxylase 발현에 미치는 영향

이기철,이정호,최영민,정주호,정홍경,이용민,김도형,이대환 大韓神經精神醫學會 2001 신경정신의학 Vol.40 No.2

연구목적: Fluoxetine은 serotonin을 매개하여 간접적으로 dopamine 신경전달기능을 억제한다고 추정되고 있다. 또한 운동장애에서 운동기능의 악화를 유발한다고 알려져 있다. 그러나 신경세포체에서 fluoxetine이 dopamine에 어떠한 영향을 주는지는 아직까지 확실치 않다. 저자들은 schedule-induced polydipsia를 유발시킨 백서 뇌의 흑질, 복부피개영역, 미상핵에서 tyrosine hydroxylase(TH) 발현이 저하됨을 발견하였다. 이를 통해서 fluoxetine이 백서 뇌의 dopamine 기능에 긍정적인지 혹은 부정적인지를 규명하고자 하였다. 방법: 4주간의 schedule-induced polydipsia 과정을 거친 백서에서 면역죄치화학적인 방법으로 흑질, 복부피개영역, 미상핵의 tyrosine hydroxylase 발현이 저하됨을 확인한 후, 실험동물들에게 fluoxetine 10mg/kg를 3주간 복강내 주사하였다. 실험백서들을 희생시켜 뇌 조직을 적출하여, TH 면역조직화학 염색법을 이용하여 흑질, 복부피개영역, 그리고 미상핵의 TH 면역반응세포를 관찰하고 이를 정상백서와 비교하였다. 결과: 1) 다갈증이 유발된 백서의 흑질, 복부피개영역, 미상핵에서 tyrosine hydroxylase 발현이 정상백서 보다 저하됨을 관찰하였다. 2) 3주간에 걸친 fluoxetine 투여후 흑질, 복부피개영역, 미상핵의 tyrosin hydroxylase 발현이 다시 증가하는 소견을 보였다. 결론: Fluoxetine 만성투여가 흑질, 복부피개영역 그리고 미상핵의 tyrosin hydroxylase를 증가시키는 소견을 얻었다. 이러한 결과는 임상에서 dopamine 결핍과 연관된 질환들에서 fluoxetine을 만성투여하면 운동기능을 포함한 증상들의 개선을 가져올 수도 있다고 추정된다. Objective: It has been suggested that fluoxetine inhibits the dopaminergic neurotransmission by serotonergic mediation. And also, it has been shown to inhibit synthesis of DOPA in dopamine-rich areas of the rat forebrain. These dopamine-antagonistic capacity of fluoxetine is only supported by anecdotal report that the increased amount of motor disability in patients with idiopathic Parkinson's disease after exposure to fluoxetine. However, there is still no evidence of the direct effect of fluoxetine on dopaminergic neuronal cell body in the substantia nigra, VTA, caudate & putamen. This study was designed to evaluate the effects of fluoxetine in rat brain which showed decreased numbers of dopaminergic neuronal cell body induced by schedule-induced polydipsia(SIP). Method: We incidentally found that 4 weeks of schedule-induced polydipsic rats revealed the suppression of tyrosine hydroxylase expression in the substantia nigra, VTA, caudate & putamen with the immunohistochemistric measures. After 3 weeks of intraperitoneal injection of 10mg/kg of fluoxetine to the schedule induced polydipsic rats, the tyrosine hydroxylase expression was also measured with immunohistochemistry. We compared the tyrosine hydroxylase expression among the normal control, the polydipsic rats, and the rats with fluoxetine treatment. Results: 1) By contrast with the control, the polydipsic rats revealed the evidence of decreased tyrosine hydroxylase expression in the substantia nigra, VTA, caudate & putamen. 2)After daily injection of fluoxetine for 3 weeks, the polydipsic rats showed increment of tyrosine hydroxyase expression in those areas. Conclusions: In previous studies, a great deal of results suggest that fluoxetine negatively influence the dopaminergic systems indirectly via serotonergic activation such as inhibition of dopamine synthesis or transport system. Although our results are obtained from rodents, we suggest that fluoxetine directly and positively enhance the dopamine system in the substantia nigra, VTA, caudate & putamen. The chronic adminstration of fluoxetine may be helpful to dopamine-depleted condition in clinical situations. We anticipate the replication studies of our findings and well-controlled clinical trial.

에탄올을 장기간 섭취한 백서에서 Acamprosate 투여가 Nitric Oxide Synthase 발현에 미치는 영향

정홍경,이기철,이정호,이승휘,이희제,정주호 대한생물치료정신의학회 2002 생물치료정신의학 Vol.8 No.1

에탄올이 백서의 해마에서 Neuropeptide Y 발현에 미치는 영향

정홍경,이기철,이정호,이희제,정주호,이주영 대한생물치료정신의학회 2002 생물치료정신의학 Vol.8 No.1

한국 정신장애의 역학 조사 연구[I] : 각 정신장애의 유병률

조맹제,함봉진,김장규,박강규,정은기,서동우,김선욱,조성진,이준영,홍진표,최용성,박종익,이동우,이기철,배재남,신정호,정인원,박종한,배안,이충경 大韓神經精神醫學會 2004 신경정신의학 Vol.43 No.4

Objectives : This study aims to estimate the prevalence of the DSM-IV psychiatric disorders in Korean population using the Korean version of Composite International Diagnostic Interview (K-CIDI). Methods : Subjects were selected by taking multi-stage, cluster samples of 7,867 adult household residents, 18 to 64 years of age, in ten catchment areas. Total 78 trained interviewers administered the K-CIDI to the selected respondents, from June 1 to November30,2001. Results : Total 6,275 respondents completed the interview. Some 33.5% of respondents reported at least one lifetime disorder, 20.6% reported at least one-year disorder, and 16.7% reported at least one-month disorder. The most common lifetime disorders were alcohol abuse/dependence (17.24%), nicotine dependence/withdrawal (11.19%), specific phobia (5.16%), and major de-pressive disorder (4.25%). The lifetime prevalence of substance abuse/dependence (0.25%) and schizophrenia (0.16%) was very low. Nicotine and alcohol use disorder showed very high male/female ratio. Mood disorder and anxiety disorder were more prevalent among female than male. Conclusion : The prevalence of psychiatric disorders was high. In comparison with other studies, remarkable differences in distributions of psychiatric disorders across the areas and times were observed.

Mannitol 투여에 의한 핍뇨성 급성 신부전 1례

이홍준,나기찬,정은경,박상기 朝鮮大學校 附設 醫學硏究所 1992 The Medical Journal of Chosun University Vol.17 No.2

Mannitol, a hexahydroxy chemically related to mannose, is a non-electrolytic, osmotic agent, It has been known that mannitol may cause serious life-threatening situation if administered in a patient with renal problem. Recently, it has been published that mannitol itself may be nephrotoxic in a patient without preexisting nephrologic disorders. We experienced a case of acute oliguric renal failure caused by long use of mannitol in order to reduce intracranial pressure and cerebral edema after operation of left posterior communicating aneurysm, and reported with recent literature review.

Risperidone이 백서의 억제된 자발적 교대행동에 미치는 영향

이기철,이정호,김진규,정홍경,천강훈,류정환,최영민,전성일 대한생물치료정신의학회 1998 생물치료정신의학 Vol.4 No.2

Objectives : Recently, some case reports have shown that risperidone is effective to refractory obsessive-compulsive disorder. Possible explanations for efficacy of risperidone in refractory obsessive-compulsive disorder maybe due to that it is both serolonin and dopamine receptor antagonist. On the basis of serotonin-dopamine interaction hypothesis, a biological etiology of obsessive-compulsive disorder, the effect of risperidone was evaluated to the suppressed spontaneous alternation behaviour of animal model of obsessive-compulsive disorder in rats. Methods : The apparatus for spontaneous alternation behaviour was a black plexiglas T-maze with distinctive black and white goal boxes. Black gullotine doors separated the start box and the goal boxes from the main body of the T-maze Small cups were placed in the corners of both goal boxes(all arms measured 50×10cm) 24 hours prior to experiment, rats(Spraque-Dawley) were food-deprived. The food-deprived rats were put into T-maze, in which both goal boxes were baited with small amounts of chocolate milk. Each rat was given 2 set of 7 trials during which it was placed in the start box and allowed to choose the one of the goal boxes for checked. After baseline of the number of choices of spontaneous alternation behaviour was stabilized, the pontaneous alternation disrupted by nonselective 5-HT agonist, 5-MeODMT (1.25mg/kg/IP). The experimental animals were stratified into 5 groups, fluoxetine(10mg/kg/IP), risperidone(0.1mg/Kg/IP), haloperidol(0.1㎎/Kg/IP), fluoxetine(10mg/Kg) with haloperidol(0.1 mg/Kg), and saline(0.5cc/IP) control group. Each drugs were injected for 21 days as a chronic treatment. The protective effects were evaluated on the nest day of discontinuation of the each drugs among 5 groups. Results : 1) After 21 days of the drug treatment, the risperidone group and the fluoxetine group showed significant difference from the haloperidol group and the saline control group on the protection of the 5-MeODMT induced suppression of spontaneous alternation behaviour. 2) The fluoxetine group and fluoxetine with haloperidol group showed significant difference between before and after treatment in the protection of 5-MeODMT induced suppression of spontaneous alternation behaviour. The risperidone group also showed significant difference between before and after treatment in the protection of 5-MeODMT induced suppression of spontaneous alternation behaviour, but the protective effect of risperidone was superior to fluoxetine. Conclusion : These findings suggest that both risperidone and fluoxetine have a favorable effect in the protection of 5-MeODMT induced suppression of spontaneous alternation behaviour. We think that risperidone can be possible alternatives to SSRIs in the treatment of refractory obsessive-compulsive disorder in clinical situation.

세로토닌성 항우울제가 백서의 Schedule-Induced Polydipsia에 미치는 영향

이기철,이정호,박중섭,최영민,전성일,정홍경,하준명,정재현 대한생물치료정신의학회 1999 생물치료정신의학 Vol.5 No.2

Object : Schedule-induced polydipsia is considered as an animal model of obsessive-compulsive disorder inrats. The authors evaluated the chronic effects of fluoxetine and clomipramine as serotonergic antidepressants and haloperidol as dopaminergic antagonist on the schedule-induced polydipsia in rat.Methods : Spraque-Dawley rats weighing 200-250gm were individually housed, maintained and allowed free access to water for 1 week. And then the rats were placed on a restricted diet. To induce polydipsia, rats were placed in automatic cage where a pellet dispenser automatically dispensed 90mg pellets on a fixed-time 60 seconds(FT 60s) feeding schedule over 150-minute test session for a day. Water was available at all times during the feeding schedule in automatic cage. After 4 weeks of daily exposure to the FT 60s feeding schedule, experimental rats met a predetermined criterion for polydipsic behavior(greater than 3 times of water per session on average). 4 groups of rats were administered fluoxetine(5mg/kg/i.p.), clomipramine(5mg/kg/i.p.), haloperidol(0.1mg/kg/i.p.), vehicle(1cc/kg/i.p.) for 3 weeks. Rats were tested once a week to access schedule induced polydipsic behavior. The chronic effects of experimental drugs on schedule induced polydipsic behavior were analyzed with repeated analysis of variance and Scheffe test as a post-hoc comparison.In order to measure water consumption in non-polydipsic food-deprived rats, a separate group of rats(N=8) were individually housed and given a single bolus(14.5 gm) of food per day which maintained them at their average body weight.Results and Conclusion : The results were as follows ;1) After 4 weeks of daily feeding procedure with fixed time schedule for 60 seconds per day, the experimental group showed significant differences than the control in the amount of water consumption as compared with their baseline water intakes. At the same periods, there were no differences between the experimental group and the control in body weight. 2) The clomipramine treated group and the fluoxetine treated group showed significant decrease in the amount of water intake as compared with their baseline of polydipsic water intakes for 3 weeks of treatment. However, the haloperidol treated group and the vehicle control group showed no changes of amounts of water intake for 3 weeks of treatment as compared with their baseline of polydipsic water intakes. 3) At 2 weeks of drug treatment, clmipramine treated group(16.88±6.51ml) and the fluoxetine treated group(22.50±10.35ml) showed significantly lower amounts of water intake than the haloperidol treated group (41.25±7.06ml) or vehicle control group(37.50±12.54ml). And also the clomipramine treated group(13.75±5.18ml) and the fluoxetine treated group(18.75±3.54ml) showed significantly lower amounts of water intake than the haloperidol group(35.00±11.65ml) and the vehicle control(34.38±6.78ml) at 3 weeks of drug treatment. Above findings suggest that the fixed time feeding procedure for schedule-induced polydipsia as an animal model of obsessive compulsive disorder was effective to the evaluation of pharmacological challenge study. The author confirmed that schedule-induced polydipsia was successfully decreased for 3 weeks of administration of clomipramine and fluoxetine but there was no response to haloperidol.

위팔동정맥루 구제를 위한 노쪽피부정맥의 지연 표재전위 : A Case Report

이홍기,박훤겸,남영수,백홍규,전순호 대한혈관외과학회 2004 Vascular Specialist International Vol.20 No.1

침전법에 의한 알루미나 분말의 제조 Ⅰ. 알루미나 분말의 제조 및 특성

홍기곤,이홍림 연세대학교 산업기술연구소 1990 논문집 Vol.22 No.1

In this study, a precipitation method, one of the most effective liquid phase reaction methods, was adopted in order to prepare high-tech Al₂O₃ceramics. Al₂(SO₄)₃·18H₂O was used as a starting material and NH₄OH as a precipitation agents. Various types of metal hydroxides were obtained by precipitation method at the pH condition between 7 and 11. Fine powders were prepared at optimum calcination condition after the properties of metal hydroxides on heat-treatment temperature were examined. The phases of aluminum hydroxides were changed from amorphous aluminum hydroxide to pseudo-boehmit of AlOOH form and bayerite, gibbsite, hydragillite and nordstrandite of Al(OH)₃form with increasing pH. Purity, average particle size and specific surface areas of α-Al₂O₃powders were 99.99%, 0.74-1.49 ㎛ and 11.1-17.4㎡/g, respectively α-Al₂O₃powders prepared in this study were soft agglomerates, and, therefore, average particle sizes were remarkably reduced to 0.06 - 0.12 ㎛ by mechanical crushing.