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.

포토센서를 이용한 풋고추 선별시스템 개발

이성범,최홍기 안성산업대학교 2002 論文集 Vol.33 No.-

The green pepper grading system was developed by recognizing length and the curved segment, Number of grading classification and factors were chosen based on the survey results of farmers. Results were summarized as following. 1. Ninety percent of surveyed farmers grade the green pepper into two classes manually according to the length, curved segment, and color. And about 10% of green peppers are being shipped without being graded, because of its highly labor intensive process. 2. Prototype having two rows of grading system (dimension : 1400×400×700mm) consists of four parts, i.e, pepper supplying device which sends one or two peppers with constant interval, separating device which carries one unit of pepper, grading device which recognizes a pepper according to the length and curved segment by the photo sensor, and discharging and control system which consists of sensors and operating pneumatic cylinder. 3. The bucket elevator type supplying system showed the best performance and it had a 30×60mm size plate mounted with 70˚angle. 4. The performance of the developed grading system showed the success rate of 97.4%. Various shapes of stalk were main error source in photo sensing. 5. The grading rate of the two-row prototype was 34kg/hr, about half of the manual operation. And its grading error was 8.3%, and it was about 20% less than the largest error of manual operation.

위팔동정맥루 구제를 위한 노쪽피부정맥의 지연 표재전위 : A Case Report

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

급성 백혈병 관해유도요법후 발생한 다발성 비장농양 1예

이홍기,김선운,박경동,이현성,주영돈,손창학 인제대학교 2000 仁濟醫學 Vol.21 No.1

Splenic abscess is a rare illness. Its incidence has ranged from 0.14 to 0.7 % in various autopsies conducted in the US. Even in the most recently published articles, diagnosis was made only in autopsies in 37 % of the cases. While splenic abscess may arise occasionally from contiguous spread of infection or direct trauma to the spleen, usually it develops with hematogenous spread or infection. But, bacterial endocarditis is the most common cause. RUQ pain of abdomen developed in only half of series. Splenomegaly, fever and leucocytosis was also present. When splenic abscesses are being considered in a differential diagnosis, CT scan of the abdomen has been the most sensitive diagnostic tool. Streptococcal species are the most common bacterial isolates from splenic abscesses, S. aureus is the next most common. Salmonella species are seen commonly in patients with sickle cell hemoglobinopathy. Because of the high mortality related for splenic abscess, the treatment of choice is splenectomy with adjunctive antibiotics. However, percutaneous drainage has been successful alternative. We reported a 19-years old female patient who had splenic abscess after remission induction chemotherapy of acute leukemia, successfully treated with splenectomy.

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.

항결핵 치료과정에서 호전되었다가 악화된 뇌 결핵종 1예 보고

이대훈,유진홍,강미자,김홍기,김선화,고동훈,천지성,유원종 대한화학요법학회 1997 대한화학요법학회지 Vol.15 No.3

In spite of nationmide tuberculosis control program, tuberculosis is still prevalent in Korea. Accordingly, tuberculous meningitis also poses one of the main trouble some problems. Recently, We experienced a perplexing case of tuberculous menin-gitis and tubercdoma in a 24-year old female patient. She was admitted to our hospital owing to meningeal irritation sign, aphasia, VI nerve palsy, and ,fever. CSF analysis showed a finding consistent with that of presumptive tuberculous meningitis.. Initial MRI of the brain revealed a large mass(tuhercu1oma) on left parieto-temporal area. Antitubeculous regimen(1soniazid (INH), rifampin(RMP), ethambutol(EMB), pyrazinamide(PZA)} of meningeal dose was given immediately, and her symptoms and signs were dramatically disappeared with a few days after treatment. She was discharged with improved condition and under maintenance treatment of tuberculosis. Follow-up one year after treatment. revealed that the previous lesion was nearly diminished. She showed no symptom at all until she recognized a total blindness of sudden onset on her left eye a t the 18th month of treatment. Brain MRI checked at that time showed multiple masses of tuberculoma scattered over the brain base and one of them invaded left optic nerve. In our opinion, the cause of relapse in this patient might he explained by the selection and ultimate replication of a minor population of resistant strain. Although such relapse is an extremely rare event, we think that we should always pay attention to this possible resistance problem every time we meet patients with tuberculous meningitis.