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천마의 GABA-benzodiazepine 수용체 복합체에 대한 조절작용
하정희,이동웅,어경윤,하정상,김현주,용철순,허근 영남대학교 약품개발연구소 1998 영남대학교 약품개발연구소 연구업적집 Vol.8 No.-
Methanol extract of G. elata inhibited the binding of [³H]Ro15-1788, a selective benzodiazepine receptor antagonist, to benzodiazepine receptor of rat cortices. Saturation experiments followed by Scatchard analysis of the results showed that the inhibition of [³H]Ro15-1788 binding by G. elata. appeared to be competitive. These competitive inhibiton of the butanol fraction was observed to be higher than the methanol extract. Methanol extract of G. elata inhibited a [³H]flunitrazepam, a selective benzodiazepine receptor agonist, binding to benzodiazepine receptor. GABA significantly enhanced the inhibition of [³H]flunitrazepam binding by G. elata, and these "positive GABA shift" supported the strong possibility of agonistic activity to benzodiazepine receptor. Butanol fraction was observed to be higher than crude extract by methanol in an agonistic activity to benzodiazepine receptor, furthermore enhanced the binding of [³H]SR95531 to GABA_(A) receptor. Butanol fraction of G. elata significantly diminished the pentylenetetrazole-induced lethality of mice. From these results, it can be concluded that substance or substances with neurochemical properties characteristic of a benzodiazepine receptor agonist may be important components, and contribute to the anticonvulsant property of G. elata.
홍윤철,임현술,하은희,정규철,조희숙,박혜숙,이용애 大韓産業醫學會 1998 대한직업환경의학회지 Vol.10 No.4
Health Risk Appraisal(HRA) is usually defined as a process by which we expect of individual's chances of death or acquiring specific diseases within a defined period of time. The concept of worksite as an area of health maintenance and promotion is newly developing. Our movement for health promotion of employees has been increasingly known in the worksite. The aim of this study is to develop health risk appraisal tools about health promotion at the worksite for employees. We performed this study by two steps; one step was to develop a HRA questionnaire of worksites in Korea, another was to evaluate the reliability of the questionnaire. For developing HRA questionnaire, we reviewed scientific examples at first, and then weighted the score by delphi. To evaluate the reliability of developed questionnaire, we carried out survey by test-retest method. A total of 131 employees completed HRA questionnaire on two times. The results are as follows. The total score of health risk in unhealthy workers was higher than that of healthy workers. The range of test-retest reliability of responses to the questionnaire was 0.57-0.94. Therefore it seems that this questionnaire was very suitable to assess the health behavior of workers. In conclusion, the developed HRA questionnaire can be used as a tool for evaluating health behavior and for providing health counseling materials.
김태하,박용철,이효진,김동화,박준건,김성준,이미연 한국환경과학회 2004 한국환경과학회지 Vol.13 No.12
Seasonal variation of biogeochemical characteristics was determined in Lake Shihwa from October 2002 to August 2003. When the lake was artificially constructed for the freshwater reservoir in 1988, the development of the strong haline density stratification resulted in two-layered system in water column and hypoxic/anoxic environment prevailed in the bottom layer due to oxidation of accumulated organic matters in the lake. Recently, seawater flux to the lake through the sluice has been increased to improve water quality in the lake since 2000, but seasonal stratification and hypoxic bottom layer of the lake still developed in the summer due to the nature of artificially enclosed lake system. As the lake is still receiving tremendous amount of organic matters and other pollutants from neighboring streams during the rainy summer season, limited seawater flux sluicing into the lake may not be enough for the physical and biogeochemical mass balance especially in the summer. The excess of accumulated organic matters in the bottom layer apparently exhausted dissolved oxygen and affected biogeochemical distributions and processes of organic and inorganic compounds in the stratified two-layered environment in the summer. During the summer, ammonia and dissolved organic carbon remarkably increased in the bottom layer due to the hypoxic/anoxic condition in the bottom layer. Phosphate also increased as the result of benthic flux from the bottom sediment. Meanwhile, dissolved organic carbon showed the highest value at the upstream area and decreased along the salinity gradient in the lake. In addition to the sources from the upstream, autochthonous origin of particulate organic carbon from algal bloom in the lake might be more important for sustaining aggravated water quality and development of deteriorated bottom environment in the summer. The removal of trace metals could be attributed to scavenging by strong insoluble metal-sulfide compounds in the hypoxic/anoxic bottom layer in the summer.
지속성 외래 복막투석 환자에서 염증 지표와 고해상도 B 모드 경동맥 초음파 소견의 연관성에 관한 연구
송현용,송영수,안철우,강신욱,최규헌,하성규,이현철,이호영,한대석 대한신장학회 2002 Kidney Research and Clinical Practice Vol.21 No.2
배 경 : 저알부민혈증 및 C-반응 단백(C-reactive protein, CRP)이 증가된 지속성 외래 복막투석 환자의 사망률이 높은 정확한 이유는 밝혀져 않다. 혈액투석 환자에서처럼 복막투석 환자에서 저알부민혈증 및 염증반응이 심혈관계 질환 위험인자 인지 알아보고자 하였다. 방 법: 비당뇨병성 말기 신부전, 지속성 외래 복막투석 환자 93명의 심혈관계 질환 위험인자들과 복막 투과 특성 및 알부민, CRP 등의 염증지표에 따라 고해상도 초음파를 이용한 경동맥내막-중간막 두께, 내막-중간막 면적, 플라크의 유무 등을 단면적으로 비교하였다. 결 과: 복막 투과 특성은 고투과막군 14명, 중간 고투과막군 38명, 중간 저투과막군 31명, 저투과막군 10명으로 각 군간의 경동맥 내막-중간막 두께, 플라크 유무 및 내막-중간막 면적의 차이는 없었다. 기존 관상동맥 질환 환자는 8예(8.6%)로 내막-중간막 두께는 관상동맥 질환이 없는 환자보다 증가되었고(0.79±0.21 vs 0.60±0.11 mm, p<0.05) 플라크 형성은 더 많이 보이나 통계적 유의성은 없었다(75.0 vs 63.5%, p>0.05). 혈청 알부민치와 경동맥 내막-중간막 면적은 역상관관계를 보였다(r=-0.27, p<0.05). 저알부민혈증 환자(혈청 알부민 <3.5 g/dL)는 정상 알부민혈증 환자보다 내막-중간막 두께가 증가되었고(0.67±0.15 vs 0.61±0.12 mm, p<0.05), 플라크도 유의하게 많았다(68.0 vs 55.8%, p<0.05). 혈청 CRP치와 경동맥 내막-중간막 면적은 양의 상관관계가 있었으며(r=0.21, p<0.05) CRP가 높은 환자(≥0.8 mg/dL, n=18)에서플라크가 많이 관찰되었으나(65.8 vs 50.0%, p<0.05) 경동맥 내막-중간막 두께 및 내막-중간막면적은 양군간에 차이가 없었다. 다변량 회귀 분석상 경동맥 내막-중간막 두께에 영향을 미치는 인자는 고령, 높은 CRP, 기존 심혈관계질환, 낮은 혈청 알부민 순이였다. 결 론 : 복막투석 환자에서 고해상도 초음파를 이용한 경동맥 내막-중간막 두께 측정은 심혈관계 질환 유무 예측의 비침습적 검사가 될 수 있고 저알부민혈증 및 높은 CRP과 같은 만성염증 지속상태가 복막투석 환자에서 죽상 동맥 경화증의 발생을 증가시킨다고 가정할 수 있다. Background : Continuous ambulatory peritoneal dialysis(CAPD) patients with low albumin(LA) and signs of inflammation reflected by increased C-reactive protein(CRP) level have an increased mortality, but the mechanism of this phenomenon is not clear yet. Methods : To answer whether LA and inflammation also enhance cardiovascular risk in CAPD patients, we performed cross sectional study measuring carotid artery intima-media thickness(IMT), calculated intima-media area(cIM area) and the presence of plaque by high-resolution B-mode ultrasonography in 93 non-diabetic CAPD patients. Results : Patients with coronary artery disease (CAD, n=8) had significantly increased IMT(0.79± 0.21 mm vs. 0.60±0.11 mm, p<0.05) and higher prevalence of carotid plaques(75.0% vs. 63.5%) compared to the non-CAD patients. Significant inverse correlation was observed between serum albumin (SA) level and cIM area(r=-0.27, p<0.05). Those patients with LA(SA <3.5 g/dL) had significantly increased IMT compared to non-LA patients(0.67±0.15 mm vs 0.61±0.12 mm, p<0.05). Prevalence of carotid plaques was also significantly higher in LA patients (68.0% vs. 55.8%, p<0.05). CRP level revealed a significant positive correlation with cIM area(r=0.21, p< 0.05). Patients with high CRP(≥0.8 mg/dL, n=18) had higher prevalence of carotid plaques (65.8% vs. 50.0%, p<0.05) compared to those patients with CRP <0.8 mg/dL, but IMT and cIMT area were not different. By multivariate logistic regression analysis, old age, high CRP, history of CAD and low SA were the independent risk factors affecting IMT. Conclusion : Our study strongly suggests that low albumin and chronic inflammatory state of CAPD patients could be associated with increasing atherosclerotic cardiovascular disease. (Korean J Nephrol 2002;21(2):285-294)
뇌 동맥류를 동반한 Takayasu's Arteritis 1례 : 증례 보고 Case Report
이하우,홍순기,한용표,허철,김헌주 대한신경외과학회 1992 Journal of Korean neurosurgical society Vol.21 No.5
A Case of Takayasu's arteritis associated with intracranial aneurysm is described. We discussed the clinical features, radiologic findings of the case, and reviewed the literatures of this disease entity.
탄화물 입자 강화 7075 Al 합금 기지 복합재료의 미끄럼마멸 특성 연구
강석하,박형철,강신철,김용석 국민대학교 생산기술연구소 2002 공학기술논문집 Vol.25 No.-
Effects of the type and volume fraction of carbide-particle-reinforcements on dry sliding wear behavior of 7075 Al alloy matrix composites were investigated. SiC, TiC and B₄C reinforced 7075 Al alloy matrix composites were manufactured by a pressureless infiltration technique and wear tested. Wear tests were carried out using a pin-on-disk wear tester with varying loads of 3N-160N at a constant sliding velocity of 0.2m/s. AISI 52100 bearing steel ball was a counterpart of the composites. Wear resistance of the composites was always higher than that of the monolithic alloy except the TiC reinforced 7075 Al matrix composite. The resistance increased with the increase of volume fraction of the reinforcing particles. Among the composites, the TiC reinforced composite had the lowest wear resistance and the B4C reinforced composite showed the highest wear resistance.
탄화물 입자 강화 7075 Al 합금 기지 복합재료의 미끄럼마멸 특성에 미치는 기지 합금 변형의 영향
강석하,강신철,김용석 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.4
Sliding wear behavior of 7075 Al alloy matrix composites was investigated. Reinforcements of the composite were SiC, TiC, and B_(4)C particles with various size and volume fractions. Sliding wear tests were carried out in an ambient atmosphere using a pin-on-disk wear tester with various loads of 5N-150N against a bearing steel ball counterpart. The composites showed higher wear resistance than the monolithic matrix alloy. Sliding wear of the composites proceeded by a grinding mechanism at low loads and by a delamination of a deformed layer at high loads. Wear resistance of the composites increased with the size and volume fraction of the reinforcements, and the increase was more significant at high applied loads. Deformation of the matrix was found to control the wear at high loads. The effect of heat treatment and reinforcement variation including size, volume fraction and species on the wear was discussed in connectin with the deformation of the matrix. (Received September 19, 2003)
정규철,이용애,홍윤철,조희숙,박혜숙,임현술,하은희 이화여자대학교 환경문제연구소 1998 이화환경연구 Vol.2 No.-
Health Risk Appraisal(HRA) is usually defined as a process by which we expect of individual's chances of acquiring specific diseases within a defined period of time. The concept of worksite as an area of health maintenance and promotion is newly developing. Our movement for health promotion of employees has been increasingly known in the worksite. The aim of this study is to develop health risk appraisal tools about health promotion at the worksite for employees. We performed this study by two steps: one step was to develop a HRA questionnaire of worksites in Korea, another was to evaluate the reliability of the questionnaire. For developing HRA questionnaire, we reviewed scientific examples at first, and then weighted the score by delphi. To evaluate the reliability of developed questionnaire, we carried out survey by test-retest method. A total of 131 employees completed HRA questionnaire on two times. The results are as follows. The total score of health risk in unhealthy workers was higher than that of healthy workers. The range of test-retest reliability of responses to the questionnaire was 0.57-0.94. Therefore it seems that this questionnaire was very suitable to assess the health behavior of workers. In conclusion, the developed HRA questionnaire can be used as a tool for evaluating health behavior and for providing health counseling materials.
가토의 하악골 연장시 Sodium fluoride 투여가 골형성에 미치는 영향
김용하,설정현,변우목,김정철,우상현,강무석 大韓成形外科學會 1999 Archives of Plastic Surgery Vol.26 No.4
The purpose of this study was to improve bone formation and shorten the period involved in distraction osteogenesis using sodium fluoride (NaF). This has been used in managing osteoporosis for several decades. This study was carried out on 40 New Zealand white rabbits. Twenty animals were used for a control group (no medication) and 20 for the experimental group. NaF 1 mg/kg/day was administered to each experimental animal via drinking water beginning 4 weeks prior to surgery and continued until sacrifice for examination. A distraction device was applied to the left mandible along a plane perpendicular to the direction of osteotomy. After a 5-day latent period, the mandibles were lengthened at 1 mm per 24 hours for 10 days. Five rabbits from each group were sacrificed on the 1st day, 2nd week, 4th week and 8th week of the consolidation period. After lengthening, all the rabbits developed a severe cross-bite. By the 4th week, cortical continuity was seen. Bone densities at the site of bony lengthening were measured by quantitative computer tomography (QCT) and dual X-ray absorptiometry (DXA). The results were as follows: the measurements of the experimental group were significantly higher than of the control group by the 1st day of the consolidation period (p<0.05) and insignificantly higher after the 2nd week. Histologically, in the experimental group, there were more osteoblasts, increased and thickened trabeculae and more mature lamellar bones than in the control group. This study showed that osteogenesis of the experimental group was significantly higher during and immediately after distraction. Our study suggested that the use of NaF could improve bone formation and decrease the period of distraction osteogenesis if a safe dose and method of fluoride administration can be determined for growing humans.