해마절편 모델에서 kainic acid에 의해 유발된 산화적 스트레스에 미치는 melatonin의 신경보호 효과

Dept. of Medical Science/석사[한글] [영문]The brain is organ with an high oxygen consumption where a lot of free radicals are present there. These free radicals attack proteins, lipids, and DNA that consist of intracellular elements to modify, damage and finally cause various diseases. In order to protect the cells and organs from diseases by this oxidative damage, the importance of antioxidant is getting increased. Melatonin, one of the free radical scavengers, is known as an antioxidant that removes the reactive oxygen species (ROS) effectively in various oxidative damage models. It is regarded as a terminal antioxidant because melatonin makes stabilized end product from melatonin by removing free radicals not through oxidation-reduction cycle.The purpose of this study is to demonstrate the effectiveness of melatonin on kainic acid (KA)-induced oxidative stresses that affect various neurodegenerative diseases. The melatonin by different concentrations and secreted melatonin from cultured pineal gland were used in organotypic hippocampal slice cultures (OHSCs) model that causes oxidative damage by using KA. Postnatal 6~8 day rats were used for OHSCs model, and slices were cultured for 3 weeks. 5 μΜ KA was treated to cultured tissues for 18 hours, and neuronal damage and ROS formation from KA by were observed measuring PI uptake and spectrum of 2’,7’- dichlorohydrofluorescein diacetate (DCFH-DA) .To observe protective effects of melatonin, two experiments were carried out. First, KA- injured OHSCs model was treated with 0.01, 0.1 and 1 mΜ of melatonin to measure the effects of melatonin by different concentrations,. Second, the co-culture method together with KA injured OHSCs was used to observe the effects of melatonin that was secreted from pineal cells.Study Ⅰ demonstrated that 0.1 and 1 mΜ of melatonin protected neuronal cell death effectively at 24 and 48 hours after melatonin treatment after measuring the PI uptake. Besides, by measuring intact cells using cresyl violet staining, the measured data correlated with PI uptake at 48 hours after melatonin treatment. After measuring the DCFH-DA spectrum, ROS formation in 0.01, 0.1 and 1 mM melatonin treated groups after 24 hours were less than KA group. In order to detect the protein expression levels of 5-lipoxigenase (5-LO), caspase-3, calmodulin and superoxide dismutase-2 (SOD-2), western blot was carried out. 5-LO, caspase-3, calmodulin, and SOD-2 expression have similar tendency. All of the expressions increased in KA-induced injury group and melatonin treated groups had reduced expressions compared to the KA-injued group.Study Ⅱ, neuronal cell death decreased at 48 hours after the treatment with melatonin co-culture using fetal and adult pineal cells. PI uptake and cresyl violet staining was carried out from this method to detect the neuronal cell death and intact neuronal cells,. Fetal and adult pineal cells co-cultured groups significantly protected neurons from neuronal cell death by KA-injury. For measuring DCFH-DA, the spectrum was decreased at 24 hours after co-culturing fetal and adult pineal cells. The expression of 5-LO, caspase-3, calmodulin, and SOD-2 significantly decreased by fetal and adult cells compared with KA only-treated group. Therefore, these results demonstrated that melatonin that was secreted from pineal cells was effective for attenuating oxidative damage.Based on the result, it is suggested that melatonin is effective on KA-induced oxidative stress in OHSCs model.ope

지방자치단체의 재정성과가 선거에 미치는 영향 : 기초자치단체장 선거를 중심으로

학위논문(석사)--서울대학교 행정대학원 :행정학과(정책학전공),2007.Maste

Financial status and voting behavior in local government: do residents respond to the financial status and operations of local government?

정부의 재정상태가 주민들의 투표행위에 어떠한 영향을 미치게 되는지에 대해서는 두 가지 이론이 대립된다. 재정상태를 건전하게 유지함으로써 투표에서 이득을 보게 된다는 견해가 있는 반면, 방만한 재정운영이 오히려 득표를 증가시킨다는 주장이 있다. 본 연구는 이와 같이 대립되는 견해에 해답의 근거를 제공하고자 지방자치단체의 재정성과에 따라 지역주민의 투표행위가 어떻게 변화하는지를 실증자료를 사용하여 살펴보았다. 우리나라 기초자치단체의 자료를 사용하여 재정상태 및 운영과 현직단체장의 득표율을 분석한 결과, 이들 사이에는 부(負)의 상관관계가 있는 것으로 나타났다. 이것은 곧, 지방재정을 효율적으로 운영하는 단체장 보다는 비효율적으로 운영하는 단체장이 더 인기가 있다는 것을 의미한다. 이러한 결과는 자치단체장들이 다음번 선거를 의식하여 방만하고 느슨한 재정운영을 한다는 주장을 뒷받침 해주고 있다. There are two theories set up in opposition concerning the effect of the financial status of local government on the voting behavior of residents. There are the assertions that maintaining sound financial status or by making use of loose financial operations can positively affect voting behavior. This paper shows how the voting behavior of residents changes according to the financial performance of local government by using positive material for providing the basis for opposition opinion. There is a negative correlation based on analysis that financial status, operations, and percentage share of the vote for the incumbent head of local government by using lower local government resources. This means that the local government head that inefficiently operates local finance is more popular than the one who does so efficiently. This result supports the assertion that local government heads operate loose finances thinking of the next election