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본 논문에서는 정상류형 혈액 펌프의 일종인 축류형 혈액 펌프를 이용하여 혈액 펌프 시스템을 설계하였다. 이 시스템은 혈액 펌프, 신호 획득부, 인터페이스부, 신호 처리부로 구성되어 있고, 혈압과 심박수를 이용하여 혈압과 혈류량을 적절히 제어함으로써 좌심실의 기능을 보조할 목적으로 연구되었다. 전동 펌프가 회전할 때 생체내의 순환조건에 알맞도록 혈액 펌프의 회전수, 혈액 펌프에 걸리는 부하와 압력 정보를 적용하여 실험식을 만들어 제어에 이용하였으며 설계 제작된 모의 순환장치로써 실험한 결과 모의 혈관 내에서 적절한 혈압과 혈류의 제어가 가능하였고, 혈구의 변화량 실험 결과는 임시의 목적으로 사용가능함을 알 수 있었다. This paper outlines the development of a non-pulsatile axial flow type blood pump control system. By utilizing blood pressure and heart rate, this system can assist the left ventricle in controlling blood pressure and blood volume. The system is comprised of a blood pump, signal sensor, signal interface, and signal-processing component. A control algorithm is also proposed which can control non-pulsatile, continuous blood flow in the human circulatory system. To facilitate the control required fur non-pulsatile blood pump in a physiological system, an experimental control rule was developed utilizing ECG and blood pressure data, both of which are easily detectable variables in the bods. The system was then tested using a mock-up circulation system and we found that it is possible that this systems could be temporarily used in clinic.
We investigated the effects of a free radical scavenger (EGb 761) and zinc in experimentally induced ischemic injury in the cat retina. Total retinal ischemia for 90 min was produced in the left eyes of 40 cats by raising intraocular pressure. In group 1, 10 cats were used as control. The free radical scavenger (EGb 761, 100 mg/kg) in group 2 (10 cats)and zinc chloride (250㎍/kg) in group 3 (10 cats) were administered intravenously at the end of ischemia. In group 4, both EGb 761 (100 mg/kg) and zinc chloride (250㎍/kg) were infected into 10 cats. ERG and a histologic study were performed 1 h, 1 day, 3 days, 1 week and 2 weeks after ischemia. The amplitude of the ERG b-wave was 62.73±0.32, 84.31±6.10, 83.65 ±12.23 and 102.4±14.27%, and the summed amplitude of oscillatory potentials was 66.16±16.42, 99.44±14.92, 95.45±6.42 and 99.62±12.32% in each group 2 weeks after ischemia. There was no significant effect in animals that received zinc alone (group 3) by the end of 1 week but some additive effect in combining EGb 761 and zinc chloride (group4) 1 h after ischemia. These findings suggest that the free radical scavenger EGb 761 may efficiently protect the retina from ischemic injury and zinc may have an additive effect when combined with a radical scavenger.
This study was designed to evaluate the efficacy of dynamic parameters, such as correlation dimension D2, by comparing spectral electroencephalographic (EEG) parameters. These parameters are used to estimate the depth of halothane anesthesia as defined by the presence of body movement in response to a tail clamp. Six rats were used and each of them was exposed to halothane sequentially at the concentrations of 0%, 0.5%, 1.0% and 1.5% for 30 min. A tail clamp was applied every five min and the movements were recorded at each concentration level. The spectral parameters and the dynamic parameters were derived from 20-sec and 10-sec segments, respectively, from the last 5-mins of EEG recording at each concentration level. Correlation coefficients between the parameters and the movements were calculated. Standardized values of three parameters, betas power, median power frequency (MPF), and D2 were derived by calcu-lation based on the number of animals showing the movement in response to a tail clamp. The betaL power had the largest correlation coefficient to spontaneous movement and to the response to a tail clamp than any other band parameter. MPF had a better correlation with the movement than 90% spectral edge frequency. Among the dynamic parameters, D2 on the parietal cortex had a better correlation with the movement. The level of deviation and variation of standardized D2, MPF, and betas were significant (p < 0.01). The order of deviation and variation was; betaL power>MPF>D2. The correlation dimension serves as a better index for the depth of halothane anesthesia defined in forms of a response to external stimulation.
미세변화 신증후군에서 세포면역지표의 변화를 분석하여 이 질환의 발병기전의 규명에 도움을 주고자 본 연구를 시행하였다. 대상 환아는 1995년 1월부터 1995년 12월 사이에 경북대학교병원 소아과에서 경피적 신생검상 미세변화신증후군으로 확진되었고, 최근 3개월간 면역억제제를 사용하지 않은 환아 19예 (연령: 2-15세)로 하였고, 대조군으로는 정상 소아 10예로 하였다. 대상환아들로 부터 재발과 관해후 1개월에 말초혈액중 T-helper와 T-suppressor 비율을 측정하고, 혈청 가용성 IL-2 수용체 (sIL-2 R)를 측정하여서 다음의 결과를 얻었다. 1.미세변화 신증후군 환아에서 재발과 관해에 따른 sIL-2 R의 유의한 변화는 없었다. 2.말초혈액의 T-suppressor는 재발 및 관해시에 정상 대조군에 비하여 유의하게 증가되었으며 (p<0.01), 특히 재발시에 이의 증가가 뚜렷하였다. 3.재발시 T-suppressor의 증가는 cyclophosphamide의 사용여부와 무관하였고, 혈청 알부민과 콜레스테롤 치와도 유의한 상관관계가 없었다. 결론적으로 미세변화 신 증후군의 발병은 T-suppressor의 증가와 관련이 있는 것 같으며, 이는 면역억제제투여나 신증후군 자체에 의한 이차적인 변화는 아닌 것으로 생각된다.
Prolonged Regional Nerve Blockade from Implantable pellets Containing Mixture of Local Anesthetics and Biodegradable Polymer Background: The Currently available local anesthetics have limitations in action duration. The duration ranges from 3 to 8 hours. Long acting anesthetic agents are particularly desirable to manage postoperative pain, relieve severe pain associated with terminal cancer, and for nerve blocks carried out in pain clinics. In this paper mixture of local anesthetics was formulated into cylindrical pellet using biodegradable polymer and its efficacy and safety was evaluated. Methods: Pellets were prepared by modified melting process with biodegradable polyester 30 wt%, bupivacaine 35 wt%, lidocaine 35 wt% and dexamethasone 0.05 wt% of polymer and drug. In vitro release kinetics of local anesthetics from pellet were determined in PBS at pH 7.4. 37℃, and the released local anesthetics were analyzed by HPLC. Nine male Sprague Dawley weighing 300∼350 gm were implanted with pellets along the sciatic nerve and the sensory blockade was assessed by an analgesiometer. The duration data were analyzed by paired t-test using SAS 6.11 Results: Local anesthetics were released in a controlled manner in vitro. In general, 40~50% of the drug released for the first day, and thereafter approximately 5% released daily. Sensory blockade lasted to beyond 2 days at the dose of 7 mg/100 g bupivacaine and lidocaine respectively. All of the animals exhibited no systemic toxicity and complete recovery. Conclusions: The results indicated that the mixture pellet demonstrated efficient and safe in prolongation of sensory blockade for significant period of time. The mechanisms underlying the mixture effect are under investigation. (Korean J Anesthesiol 1998; 34; 493∼478)
Background : Nail lacquer strengthens and protects the nail plate by preventing excess loss of moisture' and providing a hard surface. On the other hand, it may produce allergic contact and ir-ritant dermatitis, paronychial and nail bed inflammation and infection, dystrophic nails and only-cholysis. Objective : The purpose of study was to investigate the effect of the nail lacquer on the barrier function of the nail. Methods : The study population consisted of 25 healthy young subjects who had not applied the nail lacquer to the nail for the last 3 months. Nail lacquer was applied to the left thumb and middle fingernail for 6 weeks and then removed by acetone. Transonychial water loss(TOWL) of the treated left fingernails and the untreated corresponding right fingernails was measured with an Evaporimeter. Lipids of the nails were extracted from distal nail cuttings and analysed by thin layer chromatography. Results : 1. Before application of the nail lacquer, there was no difference In TOWL between the left and right fingernails while the TOWL of the thumb nail was higher than that of the middle fin-gernail with a statistical significance(p<0.05). 2. The TOWL of the left fingernails, measured 1 day, 2, 4 and 6 weeks after application of the nail lacquer, was lower than that of the entreated right fingernails with a statistical signifi-cance(p<0.05). 3. The TOWL of the left fingernails, measured 1, 3 and 7 days after removal of the nail lac-quer by acetone, was not different statistically from that of the untreated right fingernails. 4. Lipid analysis demonstrated that the cholesterol content was higher in the left fingernail which had been covered with nail lacquer than in the untreated right fingernail. 5. There was no clinical adverse effect observed during application of the nail lacquer or after removal of it. Conclusion : According to the results of the study, nail lacquer has some occlusive effects on transonychial water evaporation. Because increased cholesterol content may be due to perturba-tions of barrier function, further studies of the effect of the nail lacquer on the barrier function of the nail will be needed. (Kor J Dermatol 1997;35(1):82∼89)
Obijectives : The spontaneous tendency to arterial hypotension in cirrhotic patients makes adequate hemodialysis therapy extremely difficult. Hemedialysis in these patients may produce intradialytic hypotension, limiting the amount of ultrafiltration. These patients are also at high risk for gastrointestinal bleeding, which can be exacerbated by anticoagu-lation. Recently peritoneal dialysis has been sug-gested for the management of this population. Methods : Seven patients with chronic renal failure and liver cirrhosis treated by CAPD are described. Six of the seven patients were complicated by ascites on starting CAPD. Hepatocellular carcinoma was identified in one patient. Three had been transferred from hemodialysis for henmodynamic intolerance, one far vascular access problem. All PD catheters were surgically placed. Results : The hemodynamic tolerance was excellent in all patients. Four patients developed bleeding immediately after catheter insertion. Two patients developed early leaks and one patient late leak. Four patients had a decline in serum albumin level of 0.5 gm/dL or more during the course of chronic PD. Peritonitis occurred on average at 8.7 month interval. Three episodes of catheter removal occurred in 148 patient-months of PD(0.24 per patient-year). Four patients died while maintained on PD; three deaths were due to hepatic encephalopathy on PD far dura-tion of 4 to 60 months and the fourth was due to Perironitis after 24 months of PD. One patient died due to malnutrition after 2 months on switching to hemodialysis because of peritonitis after 32 months of PD. Conclusion : Early mechanical complications after catheter insertion(bleeding, leak) were more common than usual. But CAPD was better tolerab1e than hemodialysis and may be a reasonable choice with an acceptable survival rate in end-stage renal disease patients with preexisting liver cirrhosis.
The inhibitory effect of cyclosporin A (CsA) on nitric oxide production is not related to the immunosuppressive action of the drug, but to the renal toxicity and arterial hyper-tension. In this study the experimental interventions to reverse the inhibition of nitric oxide production by cyclosporin A in rat aortic smooth muscle cells were examined. CsA inhibited the accumulation of nitrite, the stable end product of nitric oxide, in cul-ture media in a concentration (0.1∼100㎍/ml)-dependent manner. The inhibitory effect of CsA on nitrite accumulation were not antagonized by arginine (10 mM), a substrate of nitric oxide synthase, nor by calcium ionophore A23187 (7□). Forskolin, an activator of adenlate cyclase, weich enhanced iNOS induction at transcriptional level, completely re-versed the inhibitory action of CsA on nitrite accumulation. However, PMA (2 nM) and PDB (50 nM), PKC activators, increased the inhibitory action of CsA on nitrite accumulation. From these results, it is suggested that cyclic AMP-elevating agents may be candidates of therapeutic agents in prevention and treatment of renal toxicity and arterial hypertension induced by CsA. Among conventional antihypertensive drugs, calcium channel blockers and α-blockers are preferred to βblockers.
Purpose : Recent studies suggest that nimodipine, a potent calcium-channel blocker, may improve neurological outcome after experimental hypoxia-ischemic brain injury. This study was conducted to evaluate the therapeutic effect of nimodipine on hypoxia-ischemia in immature rat brain. Methods : Seven-day postnatal rats were subjected to hypoxia-ischemia by unilateral common carotid artery occlusion combined with 2 hours of hypoxia(in 8% oxygen at an ambient tempera-ture of 36℃). Then 20 rats received an intraventricular injection of nimodipine while the remaining 23 rats were injected with saline. Histologic examinations and morphometric analyses of brain tissue specimens were carried out 2 weeks after the hypoxia-ischemia. Resu1ts : Histopathological analysis of each rat showed that the brains of the nimodipine-treated animals were less damaged when compared with control rats treated with saline. Fifty percent of nimodipine treated rats but only 13% of saline-treated rats revealed normal histologic findings(p<0.05). Gliosis &/or nerve cell necrosis were observed, over three brain lobes in 15% of nimodi-pine-treated rats and 57% of saline-treated rats respectively(p<0.05). At the level of dorsal hippocampus, saline-treated rats revealed 0.18±0.17mm smaller ipsilateral cerebral hemispheres than contralateral hemispheres to artery disections but nimodipine-treated rats showed only 0.07±0.14mm smaller hemispheres(p<0.05). The difference between contralateral and ipsilateral cerebral cortex was 0.4±0.36mm in saline-treated rats and 0.11±0.14mm in nimo-dipine-treated rats(.p<0.05). The contraction of cerebral hemisphere and cortex were significantly reduced in nimodipine-treated rats. Conclusion : The finding indicates that post-insult nimodipine treatment in the immature rat decreases the extent of hypoxic-ischemic brain damage. (J Korean Pediatr Soc 1999;42:1552-1558)
인공고관절 전치환술후 무균성 해리조직에서 Cytokine의 mRNA 발현과 Metalloproteinase의 생성 인공관절 전치환술후 장기간 수명을 결정하는 가장 중요한 요소는 인공관절에서 발생한 마모입자를 탐식한 활성화된 탐식세포에 의한 생물학적 반응에 의한 것이다. 본 연구의 목적은 이러한 무균성 해리조직에서 여러종류의 cytokine의 전령 RNA 수준에서 유전자 발현을 규명하고 부가하여 이들과 세포외기질의 분해 및 섬유화와 관계된 제 2형 및 제 9형 metalloproteinase의 생성을 밝혀냄으로써 생물학적 반응의 병인을 규명하고자 하는 것이다. 실험군으로는 시멘트형 인공관절 전치환술 후 무균성 해리로 인하여 재치환술이 필요로 한 5명의 환자에서 채취한 5례의 무균성 해리 조직을 사용하였으며 대조군으로는 2례의 대퇴 정복 골절시 인공관절 치환술이 필요로 한 환자의 고관절 활액막을 사용하였다. 이들 조직에서 총 RNA를 추출하고 역 전사하여 상보적인 DNA를 만든 후 interleukin (IL)-1α, IL-1β, IL-2 receptor (2R) , IL-4, IL-5, IL-8, IL-10, transforming growth factor-beta (TGF-β, and interferon-gamma (IFN-r)의 oligonucleotide primer와 연쇄 중합반응으로 중폭한 후 전기영동으로 발현정도를 관찰하였으며 제 2형 및 9형 metalloproteinase는 gelatin을 이용한 zymographic analysis로 분석하였다. 보조적으로 이들 조직에서 어떠한 세포가 주로 작용을 하는가 알아보기 위해 탐식세포에 특이적인 CD-69 monoclonal antibody를 이용하여 면역조직염색하였으며 활성화된 세포의 미세변화를 관찰하기 위해 전자 현미경 검사를 시행하였다. 지금까지 알려진 IL-1β, IL-8, TGF-β 이외에도 IL-2R, IL-10의 유전자발현이 관찰되었다. 제 2형 및 제 9형 metalloproteinase의 생성이 관찰되었으며 무균성 해리조직에서 대부분의 세포는 CD-68 항체에 양성인 대식세포이었다. 전자현미경 소견으로는 큰 세포핵을 가진 많은 lysosome구조를 가진 세포내 소 물질들이 발견되었으며 금속이나 폴리에틸렌 입자들이 증명되었고 세포막이 불규칙하며 주름져 있었으나, 세포의 비가역적인 변화는 관찰되지 않았다. 결론적으로 무균성해리조직에서 마모입자는 탐식한 활성화된 대식세포에서 인공관절 주위의 골용해 및 세포의 기질변성이나 섬유화로 인한 무균성해리의 국소병변에서 지금까지 밝혀진 cytokine 이외에도 국소의 항염증성 반응에 관계가 있다고 밝혀진 IL-10 및 TGF-β가 증명됨으로써 이들의 염증성 및 항염증성 cytokine의 균형이 중요하며, 항염증성 cytokine을 이용하여 이러한 국소병변의 치료에도 응용을 할 수 있다고 사료되었다. IL-2R의 유전자 발현은 인공고관절 치환술 후 발생되는 무균성 해리에 T-임파구의 관련 가능성을 시사하였으나, 이 병인에 대한 면역체계의 완전한 활성화에 대해서는 추가 연구가 필요할 것으로 사료되었다. The aim of the present study was to investigate the mRNA expression of several cytokines which were not reported previously from interface tissues around loose cemented acetabulum to obtain better understanding of the biological mechanisms connected with aseptic loosening and osteolysis of THA. We investigated mRNA expression for several cytokines (interleukin-1 alpha [IL-1α], IL-1β, IL-2, IL-2 receptor[2R], IL-4, IL-5, IL-8, IL-10, transforming growth factor-beta [TGF-β], and interferon-gamma [IFN-r]) by reverse transcription-polymerase chain reaction (RT-PCR) and release of metalloproteinase (MMP)-2 and MMP-9 from the cement-bone interface tissues around five loose polyethylene acetabular components. We did not include TNF-α and IL-6 because the biologic effect of the former is so similar to that of IL-1, and the latter fails to stimulate prostaglandin E2 or collagenase production by fibroblsts or synovial cells. Expression of mRNA for IL- 1β was detected in four, IL-2R and IL-8 in three, IL-10 and TGF-β in two of five interface tissues . No expression of mRNA for IL- lα, IL-2, IL-4, IL-5, and IFN-r was detected. Zymographic analysis for gelatinase/type IV collagenase revealed gelatinolytic bands corresponding to metalloproteinase(MMP)-2 and MMP-9 in cement-bone interface tissues. Activated cells phagocytose particles in cement-bone interface tissues expressed more cytokines mRNA than previously known to be related to periprosthetic bone resorption, and secreted metalloproteinases associated with extracellular matrix degradation and fibrosis.