• 보건행정학회지
• /
• 제27권4호
• /
• pp.273-275
• /
• 2017

It has been forty years since the implementation of National Health Insurance (NHI) in South Korea. Following the 1977 legislature mandating medical insurance for employees and dependents in firms with more than 500 employees, South Korea expanded its health insurance to urban residents in 1989. Resultantly, total expenses of the National Health Insurance Service (NHIS) have greatly increased from 4.5 billion won in 1977 to 50.89 trillion won in 2016. With multiple insurers merging into the NHI system in 2000, a single-payer healthcare system emerged, along with separation policy of prescribing and dispensing. Following such reform, an emerging financial crisis required injections from the National Health Promotion Fund. Forty years following the introduction of the NHI system, both praise and criticism have been drawn. In just 12 years, the NHI achieved the fastest health population coverage in the world. Current medical expenditure is not high relative to the rest of the Organization for Economic Cooperation and Development. The quality of acute care in Korea is one of the best in the world. There is no sign of delayed diagnosis and/or treatment for most diseases. However, the NHI has been under-insured, requiring high-levels of out-of-pocket money from patients and often causing catastrophic medical expenses. Furthermore, the current environmental circumstances of the NHI are threatening its sustainability. Low birth rate decline, as well as slow economic growth, will make sustainment of the current healthcare system difficult in the near future. An aging population will increase the amount of medical expenditure required, especially with the baby-boomer generation of those born between 1955 and 1965. Meanwhile, there is always the problem of unification for the Korean Peninsula, and what role the health insurance system will have to play when it occurs. In the presidential election, health insurance is a main issue; however, there is greater focus on expansion and expenditure than revenue. Many aspects of Korea's NHI system (1977) were modeled after the German (1883) and Japanese (1922) systems. Such systems were created during an era where infections disease control was most urgent and thus, in the current non-communicable disease (NCD) era, must be redesigned. The Korean system, which is already forty years old, must be redesigned completely. Although health insurance benefit expansion is necessary, financial measures, as well as moral hazard control measures, must also be considered. Ultimately, there are three aspects that we must consider when attempting redesign of the system. First, the health security system must be reformed. NHI and Medical Aid must be amalgamated into one system for increased effectiveness and efficiency of the system. Within the single insurer system of the NHI must be an internal market for maximum efficiency. The NHIS must be separated into regions so that regional organizers have greater responsibility over their actions. Although insurance must continue to be imposed nationally, risk-adjustment must be distributed regionally and assessed by different regional systems. Second, as a solution for the decreasing flow of insurance revenue, low premium level must be increased to an appropriate level. Likewise, the national reserve fund (No. 36, National Health Insurance Act) must be enlarged for re-unification preparation. Third, there must be revolutionary reform of benefit package. The current system built a focus on communicable diseases which is inappropriate in this NCD era. Medical benefits must not be one-time events but provide chronic disease management. Chronic care models, accountable care organization, patient-centered medical homes, and other systems that introduce various benefit packages for beneficiaries must be implemented. The reimbursement system of medical costs should be introduced to various systems for different types of care, as is the case with part C (Medicare Advantage Program) of America's Medicare system that substitutes part A and part B. Pay for performance must be expanded so that there is not only improvement in quality of care but also medical costs. Moreover, beneficiaries of the NHI system must be aware of the amount of their expenditure through a deductible payment system so that spending can be profiled and monitored. The Moon Jae-in Government has announced its plans to expand the NHI system; however, it is important that a discussion forum is created so that more accurate analysis of the NHI, its environments, and current status of health care system, can take place for reforming NHI.

• 원예과학기술지
• /
• 제33권2호
• /
• pp.202-209
• /
• 2015

본 연구는 수삽을 이용한 'Campbell Early' 포도나무의 발아 특성 관찰을 통해 눈의 내재 휴면 타파를 위한 저온축적과의 관계를 구명하고, 저온에 노출되는 동안 눈의 발달 양상을 관찰하여 발아와 휴면에 대한 기초자료를 마련하고자 하였다. 만개 120일 후(낙엽기 : 10월 7일)부터 시료를 수집하여 수삽하였으며, 만개 후 125일부터 온도가 $7.2^{\circ}C$도 이하로 내려가 CU 축적이 시작되었다. 발아율은 만개 150일 이후부터 100% 발아하였으나 165일 이후 수집된 가지에 비해 최초 발아까지의 기간이 2배 이상 소요되어 발아속도가 현저히 떨어졌다. 즉, 만개 165일 이후에는 100% 발아할 뿐만 아니라 발아 소요일수가 짧아 내재 휴면이 완전히 타파된 것으로 판단되었다. 이 기간 동안 CH 모델과 Utah 모델에 의한 저온 적산 값 계산 시, 각각 321h와 442CU로 조사되었다. 또한 이 시기 이후부터 주아의 생존율이 급격히 감소하였고, 제 1 부아의 생존율은 시기적인 차이 없이 90% 수준으로 높게 유지되었다. 화아형성이 이루어진 눈을 대상으로 조사된 주아 대비 부아의 비율은 내재 휴면이 타파되기 이전인 만개 후 150일에는 1:0.23으로 주아의 비율이 월등히 높았으나, 내재 휴면이 타파된 이후 최종적으로 만개후 255일에 이르러서는 1:1.54로 주아에 비해 부아의 비율이 높게 나타났다. 액아의 생존율 및 화아형성율과의 각 조사항목 간 상관분석에서는 주아에서만 상관관계가 인정되어 주아의 생존율 자체는 시기와 가장 밀접한 관련을 나타내었고, 주아의 생존율과 화아형성률 사이에 높은 정의 상관관계가 나타났다.

• 원예과학기술지
• /
• 제29권5호
• /
• pp.420-432
• /
• 2011

방울토마토(Lycopersicon esculentum cv. Koko) 재배 온실에 피해를 주는 온실가루이 개체군(Trialeurodes vaporariorum (Westwood))의 온도 발육 모형과 암컷 성충 산란 모형을 작성하여 시설 내 대기 중 온도와 미기상 온도인 잎 뒷면 온도를 적용한 DYMEX 프로그램(호주 CSIRO에서 개발한 미리 탑재된 모듈들을 사용하는 모의 실험 프로그램)으로 밀도 변동을 모의 실험하였다. 온도에 따라 상이한 발육 기간과 산란수를 각각 표준화시킨 발육 완료 분포 모형과 연령 특이적 산란수와 생존율을 비선형 회귀 모형에 적합시켜 밀도 변동 모의 실험을 하였다. 실제 줄내림 방식의 방울 토마토에서 토마토 식물체를 3위치(상단: 지상 1.6m 이상, 중단: 지상 0.9-1.2m 사이, 하단: 지상 0.3-0.5m 사이)로 나누어 각 위치별로 온실 내 대기 중 온도와 잎 뒷면 온도를 기록하였다. 온실 내 대기 중 온도와 잎 뒷면 온도간의 상관 관계를 비선형 회귀로 적합하여, 온실 내 미기상 온도 자료를 만들었다. 온실 내 미기상 온도 자료인 잎 뒷면 최대 온도는 대기 중 최대 온도보다 항상 낮게 유지되고 있었으며, 하단, 상단, 중단의 순으로 온도가 낮아지는 현상을 보였다. 모의 실험을 위한 시기와 초기 이입 밀도의 설정은 황색 점착 트랩을 이용하여 실제 온실에서 이입되는 시기(6월초)에 유인된 암컷 성충 10마리를 사용하였다. 온실 내 대기 중 온도 자료와 잎 뒷면 온도 자료를 각각 이용하여 온실가루이 유충의 발육 모형과 성충의 산란 모형을 DYMEX 프로그램으로 모의 실험하였다. 모의 실험 결과 검증을 위해 대기 중 온도와 잎뒷면 온도를 조사한 온실에서 토마토 식물체 3위치별, 각태별 온실가루이 밀도의 육안 조사도 실시하였다. 알의 경우 크기로 인해 육안 조사 대상에서 제외되었다. 육안 조사 결과와 육안 조사 시기의 DYMEX 모의 실험 결과값을 상관 분석하였다. 육안 조사 온실가루이 밀도와 잎 뒷면 온도를 이용한 모의 실험 결과 밀도가 모든 발육태에서 항상 양의 상관 관계를 보였다. 육안 조사 결과 밀도 변동 패턴도 방울토마토 잎 뒷면 온도를 이용한 모의 실험 결과 밀도 변동 패턴과 유사하였다. 본 연구 결과 방울토마토 온실에서 온실가루이 개체군 밀도 변동의 적절한 예측을 위해서는 잎 뒷면 온도를 고려해야 하는 것으로 나타났다.

• 생태와환경
• /
• 제40권1호
• /
• pp.130-142
• /
• 2007

본 연구에서는 용담댐의 탁수 방류로 인한 하류 하천의 영향을 알아보기 위하여 생태계 건강성 평가 모델, 물리적 서식지 평가 모델, 해부학적 건강성 평가 모델을 적용하였다. 건강성 평가 결과 $S1{\sim}S4$의 생태계 건강도는 평균 43으로 최적${\sim}$ 양호 상태였고, 물리적 서식지 건강도는 평균 154로 양호상태로 나타나 건강도가 양호하게 유지되고 있는 것으로 나타났다. 한편 개체의 건강도를 평가하는 해부학적 건강도 평가 결과 10개 메트릭에서 이상증상이 나타나지 않아 어류 건강성에 대한 영향은 없는 것으로 판단되었다. 한편, 부유물의 증가에 따른 어류 아가미의 전자현미경적 영향 분석을 위해 탁도 처리군 및 대조군의 비교분석 결과에 따르면, 어류 아가미에서 많은 부유물 미세 입자가 관찰되어 고탁도에 장기간 노출될 경우 건강성에 영향을 미칠 가능성이 있을 것으로 사료되었다. 또한, 탁도 증가에 따른 부유사 이동에 의한 어류의 물리적 서식지 영향 분석(특히, 하상 매몰도 및 하상특성 분석)을 위해 서식지 건강성 평가모델을 적용 평가한 결과에 따르면, 대상 조사지역$(S1{\sim}S4)$이 대조군 지역(C1, C2)보다 더 좋은 것으로 나타났다. 즉, 부유사의 증가는 현재의 결과로는 서식지 건강도에 영향을 주지 않는 것으로 나타나 어류의 먹이사슬, 산란장 및 서식처에 대한 부정적 영향은 없는 것으로 사료되었다. 한편, 이런 결과는 단기간 연구 결과에 의한 현재 상태의 건강도 평가의 결과이지만 향후 탁수가 지속될 경우 수 환경이 어떻게 변할 것인가에 대해서는 사후 지속적인 모니터링이 이루어져야 하며, 향후 $3{\sim}5$년 후의 지속적인 모니터링을 실시할 경우 용담댐 건설에 의한 생태 건강도가 어떻게 변할 것인지에 대한 정보를 제공하기 때문에 지속적인 모니터링이 요구된다.

• 생태와환경
• /
• 제40권2호
• /
• pp.184-192
• /
• 2007

본 연구는 국내 5대강 수계 중 하나인 섬진강 수계의 6개 지점을 선정하여 수체 안정기인 2005년 4월과 6월, 2회에 걸친 조사를 실시하여 섬진강의 생태 건강성을 진단하였다. 생물통합지수(Index of Biological Integrity, IBI)모델 분석은 국내 특성에 맞게 수정 보완된 10개 다변수 메트릭 모델(Multimetric model)을 이용하였고, 정성적 서식지 평가 지수(Qualitative Habitat Evaluation Index, QHEI) 분석은 국내 하천 특성에 맞게 변형한 11개의 다변수 메트릭 모델을 적용하였으며, 이 화학적 수질 분석은 섬진강 수계의 환경부 측정망 지점 자료 중, 2002년부터 2005년까지 4년간 측정된 자료를 이용하였다. 섬진강의 생물통합지수는 33(n=12)로서 "보통${\sim}$양호상태" (Fair${\sim}$Good)로 나타났다. 지점별 모델값은 지점 5에서 40 "양호상태" (Good)로 생물통합지수가 가장 양호한 지점으로 나타난 반면에 지점 3은 23 "악화${\sim}$보통상태" (Poor${\sim}$Fair)로 생물통합지수가 가장 악화된 지점으로 나타났다. 서식지 건강성 지수는 평균 109(n=6)으로 "일부훼손상태"(Marginal)로 나타났으며, 지점별 모델값은 지점 6에서 136으로 "양호상태" (Suboptimal), 지점 3은 54로서 "악화${\sim}$일부훼손상태" (Poor${\sim}$Marginal)로 나타났다. 이 화학적 수질자료의 지점별 분석에 따르면, 지난 4년간 평균 BOD와 COD값은 각각 1.3 mg $L^{-1}$(범위: $0.9{\sim}1.8$ mg $L^{-1}$)과 3.3 mg $L^{-1}$ (범위: $2.8{\sim}4.0$ mg $L^{-1}$)로 나타나 유기물에 의한 화학적 오염은 적은 것으로 나타났다. TN과 TP의 평균값은 각각 2.5 mg $L^{-1}$과 0.067 mg $L^{-1}$로 나타나 영양염류는 상 하류간 큰 영향을 미치지 않는 것으로 나타났다. 본 연구에서 산정된 생물통합지수와 정성적 서식지 평가, 이 화학적 수질 분석에 따르면, 섬진강의 수환경은 5대강 수계 중 어류가 서식함에 있어 가장 적합한 상태인 것으로 나타나, 서식지 교란과 화학적 오염으로부터 계속적으로 보호되어야 할 것으로 사료되었다.

• 생태와환경
• /
• 제43권3호
• /
• pp.428-436
• /
• 2010

본 연구는 태화강 수계 14개 지점을 선정하고, 2009년 5월과 9월 2차례 조사를 실시하여 이 화학적 수질, 물리적 서식지 분석을 통하여 어류 분포특성 및 생태 건강도를 진단하였다. 생물통합지수(Index of Biological Integrity, IBI)모델 분석은 국내 하천의 특성에 맞게 수정 보완하여 8개 다변수 메트릭 모델을 이용하였고, 물리적 서식지 평가 지수(Qualitative Habitat Evaluation Index, QHEI)분석은 11개의 다변수 메트릭 모델을 적용하였다. 이 화학적 수질 분석은 태화강 수계의 환경부 수질 측정망 자료 중 2000년부터 2009년까지 10년간의 자료를 이용하여 분석하였다. 태화강의 지난 10년간 평균 BOD 값은 $1.7\;mg\;L^{-1}$로서 Ib(좋음) 등급을 보였고, $0.1{\sim}31.8\;mg\;L^{-1}$의 넓은 변이폭을 보였다. COD 값은 $3.6\;mg\;L^{-1}$로서 역시 큰 변이를 보였고($0.4{\sim}33\;mg\;L^{-1}$) TN의 평균값은 $2.8\;mg\;L^{-1}$ (범위: $0.1{\sim}14.8\;mg\;L^{-1}$)로 나타났으며, TP의 평균값은 $96.8\;{\mu}g\;L^{-1}$ (범위: $0{\sim}1675\;{\mu}g\;L^{-1}$)로 나타났다. 태화강의 물리적 서식지 평가 지수 값은 67.5로 "보통상태"(C)에서 164.5 "양호상태"(B)의 분포를 보이는 것으로 나타났다. 본류의 QHEI 값은 T9 지점 이후 하류로 갈수록 울산시의 영향으로 감소하는 것으로 나타났다. 태화강의 1, 2차 조사 결과 평균 26.1(n=14)로 "양호상태"(B)로 나타났다. 태화강 수계의 본류는 울산 시내를 관통하면서 점오염원 및 비점오염원의 영향을 받아 하류로 갈수록 건강성이 악화되는 경향을 보였다. 태화강 수계의 IBI, QHEI, 이 화학적 수질을 살펴보면 서식지질과 수질의 악화로 본류는 하류로 갈수록 건강성 이 감소하는 것으로 나타났다.

• 한국수학교육학회지시리즈E:수학교육논문집
• /
• 제25권2호
• /
• pp.403-430
• /
• 2011

본 연구에서는 고등학생 6명을 대상으로 CAS 그래핑 계산기를 활용한 수업이 대수 영역에 대한 학생들의 개념 이해에 어떤 영향을 주는지 알아보고, 협동 수업에서 학생들이 방정식, 부등식, 함수의 개념을 각각 어떻게 연결 짓는지 살펴보았다. 또한 CAS 그래핑 계산기를 활용한 수업 이후 학생들의 수학적 태도가 어떻게 변화되었는지 알아보았다. 연구 결과 그래핑 계산기는 학생들이 지필로 푼 문제를 확인하고 그 결과를 비교할 수 있도록 하며, 지필로 푼 문제에 대한 즉각적인 피드백을 제공하여 학생들이 방정식과 일차 부등식을 자기 반성적으로 학습하도록 도와주었다. 이차 부등식에서는 학생들이 기존에 암기하고 있었던 공식으로 문제를 푸는 것에 한계를 느끼게 함으로써 기존에 가지고 있었던 잘못된 개념을 수정하고 이차 함수를 통하여 이차 부등식의 근본적인 개념을 이해하도록 도와주었다. 함수에서는 함수의 정의를 여러 가지 문자와 수식을 이용하여 빠르게 파악할 수 있게 하였으며, 함수에 대한 직관적인 이해를 가능하게 하였다. 또한 그래핑 계산기의 활용은 방정식, 부등식, 함수 영역 간의 연결을 가능하게 도와주었고, 학생들에게 수학의 유용성과 실용성을 느낄 수 있게 하였다. 그리고 학생들의 수학적 태도를 긍정적으로 변화시켰다.

• Asia pacific journal of information systems
• /
• 제20권2호
• /
• pp.125-155
• /
• 2010

Ontologies have been adopted in various business and scientific communities as a key component of the Semantic Web. Despite the increasing importance of ontologies, ontology developers still perceive construction tasks as a challenge. A clearly defined and well-structured methodology can reduce the time required to develop an ontology and increase the probability of success of a project. However, no reliable knowledge-engineering methodology for ontology development currently exists; every methodology has been tailored toward the development of a particular ontology. In this study, we developed a Graduation Screen Ontology (GSO). The graduation screen domain was chosen for the several reasons. First, the graduation screen process is a complicated task requiring a complex reasoning process. Second, GSO may be reused for other universities because the graduation screen process is similar for most universities. Finally, GSO can be built within a given period because the size of the selected domain is reasonable. No standard ontology development methodology exists; thus, one of the existing ontology development methodologies had to be chosen. The most important considerations for selecting the ontology development methodology of GSO included whether it can be applied to a new domain; whether it covers a broader set of development tasks; and whether it gives sufficient explanation of each development task. We evaluated various ontology development methodologies based on the evaluation framework proposed by G$\acute{o}$mez-P$\acute{e}$rez et al. We concluded that METHONTOLOGY was the most applicable to the building of GSO for this study. METHONTOLOGY was derived from the experience of developing Chemical Ontology at the Polytechnic University of Madrid by Fern$\acute{a}$ndez-L$\acute{o}$pez et al. and is regarded as the most mature ontology development methodology. METHONTOLOGY describes a very detailed approach for building an ontology under a centralized development environment at the conceptual level. This methodology consists of three broad processes, with each process containing specific sub-processes: management (scheduling, control, and quality assurance); development (specification, conceptualization, formalization, implementation, and maintenance); and support process (knowledge acquisition, evaluation, documentation, configuration management, and integration). An ontology development language and ontology development tool for GSO construction also had to be selected. We adopted OWL-DL as the ontology development language. OWL was selected because of its computational quality of consistency in checking and classification, which is crucial in developing coherent and useful ontological models for very complex domains. In addition, Protege-OWL was chosen for an ontology development tool because it is supported by METHONTOLOGY and is widely used because of its platform-independent characteristics. Based on the GSO development experience of the researchers, some issues relating to the METHONTOLOGY, OWL-DL, and Prot$\acute{e}$g$\acute{e}$-OWL were identified. We focused on presenting drawbacks of METHONTOLOGY and discussing how each weakness could be addressed. First, METHONTOLOGY insists that domain experts who do not have ontology construction experience can easily build ontologies. However, it is still difficult for these domain experts to develop a sophisticated ontology, especially if they have insufficient background knowledge related to the ontology. Second, METHONTOLOGY does not include a development stage called the "feasibility study." This pre-development stage helps developers ensure not only that a planned ontology is necessary and sufficiently valuable to begin an ontology building project, but also to determine whether the project will be successful. Third, METHONTOLOGY excludes an explanation on the use and integration of existing ontologies. If an additional stage for considering reuse is introduced, developers might share benefits of reuse. Fourth, METHONTOLOGY fails to address the importance of collaboration. This methodology needs to explain the allocation of specific tasks to different developer groups, and how to combine these tasks once specific given jobs are completed. Fifth, METHONTOLOGY fails to suggest the methods and techniques applied in the conceptualization stage sufficiently. Introducing methods of concept extraction from multiple informal sources or methods of identifying relations may enhance the quality of ontologies. Sixth, METHONTOLOGY does not provide an evaluation process to confirm whether WebODE perfectly transforms a conceptual ontology into a formal ontology. It also does not guarantee whether the outcomes of the conceptualization stage are completely reflected in the implementation stage. Seventh, METHONTOLOGY needs to add criteria for user evaluation of the actual use of the constructed ontology under user environments. Eighth, although METHONTOLOGY allows continual knowledge acquisition while working on the ontology development process, consistent updates can be difficult for developers. Ninth, METHONTOLOGY demands that developers complete various documents during the conceptualization stage; thus, it can be considered a heavy methodology. Adopting an agile methodology will result in reinforcing active communication among developers and reducing the burden of documentation completion. Finally, this study concludes with contributions and practical implications. No previous research has addressed issues related to METHONTOLOGY from empirical experiences; this study is an initial attempt. In addition, several lessons learned from the development experience are discussed. This study also affords some insights for ontology methodology researchers who want to design a more advanced ontology development methodology.

• Asia pacific journal of information systems
• /
• 제24권2호
• /
• pp.233-253
• /
• 2014

Can the stock market really be predicted? Stock market prediction has attracted much attention from many fields including business, economics, statistics, and mathematics. Early research on stock market prediction was based on random walk theory (RWT) and the efficient market hypothesis (EMH). According to the EMH, stock market are largely driven by new information rather than present and past prices. Since it is unpredictable, stock market will follow a random walk. Even though these theories, Schumaker [2010] asserted that people keep trying to predict the stock market by using artificial intelligence, statistical estimates, and mathematical models. Mathematical approaches include Percolation Methods, Log-Periodic Oscillations and Wavelet Transforms to model future prices. Examples of artificial intelligence approaches that deals with optimization and machine learning are Genetic Algorithms, Support Vector Machines (SVM) and Neural Networks. Statistical approaches typically predicts the future by using past stock market data. Recently, financial engineers have started to predict the stock prices movement pattern by using the SNS data. SNS is the place where peoples opinions and ideas are freely flow and affect others' beliefs on certain things. Through word-of-mouth in SNS, people share product usage experiences, subjective feelings, and commonly accompanying sentiment or mood with others. An increasing number of empirical analyses of sentiment and mood are based on textual collections of public user generated data on the web. The Opinion mining is one domain of the data mining fields extracting public opinions exposed in SNS by utilizing data mining. There have been many studies on the issues of opinion mining from Web sources such as product reviews, forum posts and blogs. In relation to this literatures, we are trying to understand the effects of SNS exposures of firms on stock prices in Korea. Similarly to Bollen et al. [2011], we empirically analyze the impact of SNS exposures on stock return rates. We use Social Metrics by Daum Soft, an SNS big data analysis company in Korea. Social Metrics provides trends and public opinions in Twitter and blogs by using natural language process and analysis tools. It collects the sentences circulated in the Twitter in real time, and breaks down these sentences into the word units and then extracts keywords. In this study, we classify firms' exposures in SNS into two groups: positive and negative. To test the correlation and causation relationship between SNS exposures and stock price returns, we first collect 252 firms' stock prices and KRX100 index in the Korea Stock Exchange (KRX) from May 25, 2012 to September 1, 2012. We also gather the public attitudes (positive, negative) about these firms from Social Metrics over the same period of time. We conduct regression analysis between stock prices and the number of SNS exposures. Having checked the correlation between the two variables, we perform Granger causality test to see the causation direction between the two variables. The research result is that the number of total SNS exposures is positively related with stock market returns. The number of positive mentions of has also positive relationship with stock market returns. Contrarily, the number of negative mentions has negative relationship with stock market returns, but this relationship is statistically not significant. This means that the impact of positive mentions is statistically bigger than the impact of negative mentions. We also investigate whether the impacts are moderated by industry type and firm's size. We find that the SNS exposures impacts are bigger for IT firms than for non-IT firms, and bigger for small sized firms than for large sized firms. The results of Granger causality test shows change of stock price return is caused by SNS exposures, while the causation of the other way round is not significant. Therefore the correlation relationship between SNS exposures and stock prices has uni-direction causality. The more a firm is exposed in SNS, the more is the stock price likely to increase, while stock price changes may not cause more SNS mentions.

• 한국동물번식학회:학술대회논문집
• /
• 한국동물번식학회 2000년도 국제심포지움
• /
• pp.10-12
• /
• 2000

Members of the glycoprotein family, which includes CG, LH, FSH and TSH, comprise two noncovalently linked $\alpha$- and $\beta$-subunits. Equine chorionic gonadotropin (eCG), known as PMSG, has a number of interesting and unique characteristics since it appears to be a single molecule that possesses both LH- and FSH-like activities in other species than the horse. This dual activity of eCG in heterologous species is of fundamental interest to the study of the structure-function relationships of gonadotropins and their receptors. CG and LH $\beta$ genes are different in primates. In horse, however, a single gene encodes both eCG and eLH $\beta$-subunits. The subunit mRNA levels seem to be independently regulated and their imbalance may account for differences in the quantities of $\alpha$ - and $\beta$ -subunits in the placenta and pituitary. The dual activities of eCG could be separated by removal of the N-linked oligosaccharide on the $\alpha$-subunit Asn 56 or CTP-associated O-linked oligosaccharides. The tethered-eCG was. efficiently secreted and showed similar LH-like activity to the dimeric eCG. Interestingly, the FSH-like activity of the tethered-eCG was increased markedly in comparison with the native and wild type eCG. These results also suggest that this molecular can implay particular models of FSH-like activity not LH-like activity in the eCG/indicate that the constructs of tethered molecule will be useful in the study of mutants that affect subunit association and/or secretion. A single-chain analog can also be constructed to include additional hormone-specific bioactive generating potentially efficacious compounds that have only FSH-like activity. The LH/CG receptor (LH/CGR), a membrane glycoprotein that is present on testicular Leydig cells and ovarian theca, granulosa, luteal, and interstitial cells, plays a pivotal role in the regulation of gonadal development and function in males as well as in nonpregnant and pregnant females. The LH/CGR is a member of the family of G protein-coupled receptors and its structure is predicted to consist of a large extracellular domain connected to a bundle of seven membrane-spanning a-helices. The LH/CGR phosphorylation can be induced with a phorbol ester, but not with a calcium ionophore. The truncated form of LHR also was down-regulated normally in response to hCG stimulation. In contrast, the cell lines expressing LHR-t63I or LHR-628, the two phosphorylation-negative receptor mutant, showed a delay in the early phase of hCG-induced desensitization, a complete loss of PMA-induced desensitization, and an increase in the rate of hCG-induced receptor down-regulation. These results clearly show that residues 632-653 in the C-terminal tail of the LHR are involved in PMA-induced desensitization, hCG-induced desensitization, and hCG-induced down-regulation. Recently, constitutively activating mutations of the receptor have been identified that are associated with familial male-precocious puberty. Cells expressing LHR-D556Y bind hCG with normal affinity, exhibit a 25-fold increase in basal cAMP and respond to hCG with a normal increase in cAMP accumulation. This mutation enhances the internalization of the free and agonist-occupied receptors ~2- and ~17-fold, respectively. We conclude that the state of activation of the LHR can modulate its basal and/or agonist-stimulated internalization. Since the internalization of hCG is involved in the termination of hCG actions, we suggest that the lack of responsiveness detected in cells expressing LHR-L435R is due to the fast rate of internalization of the bound hCG. This statement is supported by the finding that hCG responsiveness is restored when the cells are lysed and signal transduction is measured in a subcellular fraction (membranes) that cannot internalize the bound hormone.