Toluene, Xylene, Trichloroethylene 투여가 흰쥐의 시상하부와 뇌하수체의 GnRH, GnRH Receptor, Pit-1 유전자 발현에 미치는 영향

기노석,이종태,강대성,김대환,이채관,이헌,전진호,김정호,이채언 大韓産業醫學會 1998 대한직업환경의학회지 Vol.10 No.2

The workplace exposure of chemicals has steadily increased, therefore the concern for subsequent effect on reproductive outcome has been an important issue in occupational medicine. In previous studies, higher rates of spontaneous abortion, reduced fertility and menstrual disorder among women, and an impairement of sperm quantity and quality among men have been associated with a wide variety of chemical agents. This study was conducted to evaluate the effects of toluene, xylene and trichloroethylene(TCE) injection on the mRNA levels of GnRH, GnRH receptor and Pit-1 genes in male rats hypothalamus and pituitary and the effects on the plasma levels of FSH, LH, prolactin and testosterone. Sprague-Dawley male rats were divided into five groups of five each according to concentration of toluene, xylene and TCE. The rats were injected subcutaneously to 0, 50, 100, 200, 400 mg/kg body weight/day of toluene, xylene and TCE, respectively for 6 days. Rat brains were excised and hypothalamus and pituitary were separated. Reverse transcription-polymerase chain reaction (RT-PCR) and RNase protection assay(RPA) were used to evaluate the GnRH, GnRH receptor and Pit-1 mRNA levels. Plasma concentrations of FSH, LH, prolactin and testosterone were assayed by radioimmunoassay(RIA). The results were as follows; 1. GnRH, GnRH receptor and Pit-1 mRNA levels in toluene and xylene injected groups, and GnRH receptor mRNA levels in TCE injected group were lowered dose-dependently. Especially, GnRH receptor and Pit-1 mRNA levels in 200mg/kg of toluene injected group, and GnRH, GnRH receptor and Pit-1 mRNA levels in 400mg/kg of toluene injected group were significantly lower than control group (p<0.05). GnRH receptor and Pit-1 mRNA levels in 400mg/kg of xylene injected group, and GnRH receptor mRNA levels in 400mg/kg of TCE injected group were significantly lower than control group(p<0.05). 2. The plasma levels of prolactin and testosterone in 400mg/kg of toluene injected group, and LH in 100, 200 and 400mg/kg of xylene injected group, and testosterone in 400 mg/kg of TCE injected group were significantly lower than control group(p<0.05). In conclusion, we speculated that toluene and xylene affected reproductive system secondarily through hypothalamus-pituitary axis, and TCE affected directly through steroidogenesis. And we recommended that further study for assessment of the reproductive toxicity of mixed organic solvent exposures should be conducted.

Slide Session : OS-IFD-07 ; Infectious Disease : In Vitro Antiviral Activity of Ribavirin Against Severe Fever with Thrombocytopenia Syndrome Virus

( Myung Jin Lee ),( Kye Hyung Kim ),( Jong Youn Yi ),( Su Jin Choi ),( Chung Jong Kim ),( Nak Hyun Kim ),( Kyoung Ho Song ),( Pyoeng Gyun Choi ),( Ji Hwan Bang ),( Wan Beom Park ),( Eu Suk Kim ),( San 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

In Vitro Antiviral Activity of Ribavirin Against Severe Fever with Thrombocytopenia Syndrome Virus Myung Jin LEE1, Kye-Hyung KIM1, Jongyoun YI2, SuJin CHOI1, Chung-Jong KIM1, Nak- Hyun KIM1, Kyoung-Ho SONG1, Pyoeng Gyun CHOI1, Ji-Hwan BANG1, Wan Beom PARK1, Eu Suk KIM1, Sang-Won PARK1, Hong Bin KIM1, Nam Joong KIM1, Myoung- Don OH1 Seoul National University College of Medicine, Korea1, Pusan National University School of Medicine, Korea2 Background: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by a novel Bunyavirus, severe fever with thrombocytopenia syndrome virus (SFTSV). No effective antiviral therapy is proven yet, but clinical use of ribavirin (RBV) has been tried. We investigated the antiviral effect of RBV against SFTSV in vitro. Methods: To test for cytotoxicity of RBV, Vero cells were treated with different concentrations of RBV (3.90 to 500 μg/mL, two-fold dilution) and analyzed by cell viability MTS assay 48h post-infection. To determine antiviral activity of RBV against SFTSV, Vero cells were infected with SFTSV strain Gangwon/Korea/2012 at 100 TCID50 (50% tissue culture infective dose) per well in a 96-well plate, and RBV was added at the concentrations showing no or minimal cytotoxicity. Viral RNAs were extracted from the culture supernatants and quantifi ed using one-step real-time reverse transcription- PCR to amplify the partial large segment of SFTSV. Statistical analysis was done by one-way ANOVA with Tukey`s post hoc test. Results: Cytotoxicity due to RBV was not observed at RBV concentration =31.3 μg/ mL. Viral RNAs at 24h post-RBV treatment were reduced with increasing RBV concentrations (1-32 μg/mL), compared with those of mock-treated cells (P <0.01, Figure). Half maximal inhibitory concentration (IC50) of RBV was 3.69 μg/mL at 24h post-RBV treatment. Conclusions: Our study shows that RBV has antiviral effect against SFTSV in a dose-dependent manner. Further studies are required to evaluate the effi cacy of RBV in SFTS.

생분해성 다공질 Calcium Phosphate 세라믹스의 제조

이경주,이중환,김석영 嶺南大學校 工業技術硏究所 1995 工業技術硏究所論文集 Vol.23 No.2

When porous calcium phosphate ceramics are used as a bone graft substitute, it is known that new tissue or blood vessel is grown into the porous implant due to their excellent biocompatibility. In this study, the most chemically stable β-crystalline form of calcium metaphosphate, Ca(PO₃)₂is prepared by the controlled thermolysis of monocalcium phosphate, Ca(H₂PO₄)₂. The diameter of cylindrical pores formed during cooling was controlled by a holding time at the melting point of a monocalcium phosphate and by the change of a recrystallization temperature, to obtain the most appropriate size(about 200㎛) of pores. It was observed that the increasing holding time at the melting point of monocalcium phosphate results in the decreases of pore sizes.

HELLP증후군의 임상양상과 예후에 관한 연구

이창환,손성경,이석수,이윤이 충남대학교 의과대학 지역사회의학연구소 1999 충남의대잡지 Vol.26 No.2

The syndrome of hemolysis, elevated liver enzymes and low platelet count during pregnancy (HELLP syndrome) is recognized as a serous, multisystemic disease and associated with poor maternal and perinatal outcome. The purpose of this study is to elevate the clinical appearance and the maternal and perinatal outcome with HELLP syndrome. It was a retrospective study that maternal outcome and perinatal variables and the clinical course of eight cases HELLP syndrome in 234 cases with pregnancy induced hypertension who visited the Department of Obstetrics and Gynecology, Chungnam National University Hospital from January 1995 to December 1998. The results were as follows; 1. The incidence of the HELLP syndrome among patient with pregnancy induced hypertension was 3.4%(8/234) and mean age, mean gestational age was each 29.7 year-old, 36.7 weeks and there was 3 primigravidas and 5 multipara(38% vs 62%). 2. In the abnormal elevated laboratory finding on admission, mean platelet count, sGOT, sGPT, total bilirubin, LDH, BUN, and creatinine was each as 74,000/㎣, 2231U/ℓ, 1941U/ℓ, 1.7mg/㎗, 10951U/ℓ, 22.3mg/㎗ and 2.0mg/㎗. 3. About the coagulation system, PT and aPTT were all within the normal limit but in 38% of patient with HELLP syndrome fibrinogen was decreased, in 50% FDP was increased and in 25% patient was made diagnosis of DIC. 4. The 6 cases were perceived as immediate delivery, one case was vaginal delivery only and others cesarean section and maternal complication was placenta abruption, severe pulmonary edema, acute renal insufficiency, acute toxic hepatitis and cardiomyopathy but there was no maternal mortality in all cases. 5. The mean birth weight 2,374g, 50% of fetus were delivered before 38 weeks, the IUGR was found in 25% and the perinatal mortality rate was 25%. 6. Neonatal complication was neonatal asphyxia, RDS(> 2 grade), sepsis, hyperbilirubinemia, hypermagnesemia, TTN and major handicaps of PVL. These findings suggest that infants born to HELLP syndrome mother have an increased need for resuscitation at delivery and aggressive management for mothers. Thus obstetricians should be identified promptly and need for appropriate management of nowborn infant and mothers with HELLP syndrome.

CFRP 복합재 적층판의 파괴메카니즘에 관한 연구

이권범,박환규,홍석주,김기형 조선대학교 동력자원연구소 1996 動力資源硏究所誌 Vol.18 No.1

In this study, when CFRP lamimates are subjected to static loading by the indentation of steel ball to examine a failure mechanism of lamimates, the fracture surface of interlaminar delamination generated at interfaces is investigated by the scanning electron microscopy (SEM). When orthotropic CFRP laimates stacked with two interface are subjected to static loading, interlaminar delaminations extend from the loading side to delamination edge even at any interface, and the fracture surface fo interlaminar delamination generated at two interfaces is symmertrically formed. In the CFRP laminates, the fracture mechanism sppears mainly to be the mixed mode(modes Ⅰ+Ⅱ), and the ratio of mixed mode varies partially. After the fracture initiates at the interface near the loading side with mode Ⅰ, the mixed mode gradually developes, but the total surface at the opposite plane to the loading side fractures with the mixed mode(modes Ⅰ+Ⅱ). While transverse cracks are generated, the direction of shear stresses reverses itself ar the delaminated surface, clarified by the hackle direction of fracture surface.

임베디드 OS를 사용한 개선된 Network Attached Storage 개발

이성화,문석환 제주한라대학 2003 論文集 Vol.27 No.-

Generally. 90% of data saved in disks by current companies are sometimes the ones not being used at all. The sudden increase of data are led to the expansion of companies' storages especially the capacity of the discs. However, from the standpoint of the companies. they cannot expand the capacity of the disc recklessly. Therefore. instead of importing expensive foreign products. it is necessary to develop high quality products of cheap price so that the small and medium companies can also introduce without difficulty. The device suggested from this study is Network Attached Storage system. It is the same concept with the existing File Server. It has capability of keeping all the data, yet. it is different technology compared to the existing concept. T! his product's operative system was developed to be fit for the product that it is the best-suited product in its efficiency. And in order to lower the cost of the product. I have used ATP disc. And to enhance the credibility of the product. I have stablized the system by using RAID technology. Also in order to minimize down time. I have enabled the system to drive within 5 minutes. The technology suggested from this study can be applied to wherever the large capacity media storage and the network occurred same time is wanted such as education-related department and etc.

다공질 실리콘 카바이드의 제작 및 광발광 성질

이기환,오제직,최석남,박병빈,이태호,김영유 공주대학교 사범대학 과학교육연구소 1998 과학교육연구 Vol.29 No.1

p-type α-SiC(4H, 6H, 15R polytype)를 사용하여 다공질 실리콘(porous silicon; PS)의 제작방법과 유사하게 HF/H₂O/C₂H??OH 용액에서 전기화학적으로 에칭을 하여 광발광 특성을 가지는 다공질 실리콘 카바이드(porous silicon carbide; PSC)를 제작하였다. PSC의 다공질의 분포는 전류밀도가 증가할수록 증가하고 다공질의 크기는 감소하였으며 광발광(photoluminescence; PL) 스펙트럼의 분석을 통해 전극 표면에서의 산화반응은 공급되는 전자의 양과 전류밀도에 의존하며 전류밀도가 증가할수록 전극의 산화반응은 억제된다는 결과를 얻었다. Porous silicon carbide(PSC) having photoluminescence(PL) can be prepared by a technique very similar to that used in porous silicon preparation, by electrochemical etching of crystalline p-type α-SiC(4H, 6H, 15R polytype) in ?? solution. The results show that porous distribution increase with increasing of the current densities while pore size decrease with that. Through the PL spectra analysis anodic oxidation of electrode surface was dependent on the amount of provided electrons and the current densities and inhibited with increasing of the current densities.

유전자 불안정성의 기전과 임상적 적용

이석환 대한대장항문학회 2004 Annals of Coloproctolgy Vol.20 No.1

다중처리 시스템에서 향상된 부하분산에 관한 연구

이성화,문석환 제주한라대학 2001 論文集 Vol.25 No.-

In this thesis, an advanced load balancing algorithm for distributed systems is presented. The distributed parallel processing has emerged as a key technology in modern computers for higher performance and lower costs. In ideal case, the performance of a distributed system will increase linearly with the number of processors. But actually, the performance curve is not ideal because of the saturation effect. In distributed systems, processors have different work loads for instance, some of the processors are idle while others are still working. This causes a degradation of the system performance. The load balancing is conducted by transferring some task from heavily loaded processors to lightly loaded processors. In this paper, an advanced load balancing algorithm in nth order Hypercube distributed system has been proposed. The new algorithm uses centralized load-balancing to avoid blocking phenomenon and processor thrashing, and shows the results which makes loads to approach average value of loads. The new algorithm is compared with several other algorithm and it shows a merit in cost function value.

포르피린증 환자에서 보인 가역적 자기공명영상소견 1례

강석윤,마효일,곽규환,이상암 대한신경과학회 1998 대한신경과학회지 Vol.16 No.2