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        검색결과 21

        1.
        2019.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study aimed to examine the effect of a mild elevation in serum cholesterol level in a porcine coronary overstretch restenosis model using a balloon angioplasty catheter or drug-eluting coronary stent. Pigs were divided into two groups and were fed a commercial normal diet (CND, n = 4) or a high-fat diet (HFD, n = 4) for 5 weeks. Coronary overstretch injury by balloon angioplasty or stent implantation was induced in the left anterior descending and left circumflex artery after 1 week of feeding. Histopathological analysis was performed at 4 weeks after coronary injury. During the experiment, the total cholesterol level in the HFD group increased by approximately 44.9% (from 65.9 ± 3.21 mg/dL at baseline to 95.5 ± 9.94 mg/dL at 5 weeks). The lumen area in the CND group was reduced in comparison with that in the HFD group after balloon angioplasty. After stent implantation, the injury score showed no significant difference. There were significant differences in the neointimal area (2.7 ± 0.33 mm2 in the CND group vs. 3.3 ± 0.34 mm2 in the HFD group, p<0.05), lumen area (2.6 ± 0.54 mm2 in the CND group vs. 2.0 ± 0.33 mm2 in the HFD group, p<0.05), and percent area stenosis (52.0 ± 7.96% in the CND group vs. 62.4 ± 5.15% in the HFD group, p<0.05). Body weight change was not different between the two groups. Increased serum cholesterol level activated vascular smooth muscle cell proliferation in the porcine coronary overstretch model.
        4,000원
        2.
        2019.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Acute myocardial infarction (AMI) is considered the major cause of mortality in the world. Tremendous animal studies are performed to develop novel therapeutics, and this study aimed to induce porcine myocardial infarction model by using polyethylene terephthalate (PET). Coronary guidewire was placed in left anterior descending artery (LAD). The balloon angioplasty catheter was inserted at the back of the PET. The balloon catheter was carefully pushed forward, until the balloon marker was located in mid-LAD. Coronary angiography was performed pre- and post-occlusion at 28 days by C-arm. Histologic analysis of heart tissue was performed 28 days after inducing AMI. Thirty three pigs were anesthetized and underwent percutaneous coronary catheterization. All pigs were successfully embolized in mid-LAD by PET. Fifteen pigs died due to ventricular fibrillation during post-anesthetic recovery time, and overall experiment mortality was 45.5%. In 2,3,5- triphenyl tetrazolium chloride staining, gross finding of the ischemic heart lesion showed firm and white area of infarction associated with the apex and left ventricular posterior wall. Infarct on H&E-stained sections demonstrated a region without myocytes and rich with cardiomyocyte with atypical nuclei. Successful induction of AMI by using PET may provide the pathophysiological information of ischemic heart disease and improvement of therapy development for AMI.
        4,000원
        3.
        2016.10 구독 인증기관·개인회원 무료
        The structural diversity and localization of cell surface glycosphingolipids (GSLs), including gangliosides, in glycolipid-enriched microdomains (GEMs) render them ideally suited to play important roles in mediating cell recognition, adhesion, interactions, receptor function, and signaling. Gangliosides, sialic acid-containing GSLs, are most abundant in the nerve tissues. The quantity and expression pattern of gangliosides in brain change drastically throughout development and these changes are mainly regulated through stage-specific expression of glycosyltransferase genes. However, roles of gangliosides in neuronal differentiation of mesenchymal stem cells (MSCs) is unclear. We previously demonstrated for the first time that the glycosyltransferase genes during mouse embryogenesis. So, we investigated the effects of ganglioside gene in differentiation of adipose-derived MSCs (AD-MSCs). GM2 and GD3 ganglioside synthease were increased during neuronal differentiation of AD-MSCs. This study showed that the differentiation of neuronal marker was decreased on the first step of ganglioside synthase UDP-glucose ceramide glucosyltransferase(UGCG) and knock downed GM2 sythase (B4GALNT1). The result of suggested that GM2 and GD3 might be important roles in the neural differentiation of mini-pig AD-MSCs. This work was carried out with the funding of the cooperative research Program for Agriculture Science & Technology Development[Project No. PJ00999901], the Rural Development Adiministration, the KRIBB Research Initiative Program[KGM4251622].
        4.
        2012.12 구독 인증기관 무료, 개인회원 유료
        Flavonoids have a range of biological activities, including anti-allergic, anti-inflammatory, anti-microbial, and anti-cancer activities, as demonstrated by in vitro studies. In this study, we investigated whether luteolin can be applied to suppression of lipopolysaccharide (LPS)-stimulated inflammatory responses in murine macrophages. Luteolin was found to reduce nitric oxide (NO) production in LPS-stimulated Raw 264.7 cells. In addition, expression of inducible nitric oxide synthetase (iNOS), cyclooxygenase-2 (COX-2), and pro-inflammatory cytokine tumor necrotic factor-α (TNF-α) at the mRNA and protein levels were decreased. These inhibitory effects were found to be caused by the blockade of nuclear factor kappa-light- chain-enhancer of activated B cells (NF-κB) activation and phosphorylation of mitogen-activated protein (MAP) kinase family, extracellular signal-regulated kinases 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), and p38 MAP kinase. In addition, pre-treatment with luteolin resulted in reduced ganglioside expression levels and inhibited expression of GT1b in Raw 264.7 cells. On the basis of these observations, we suggest that luteolin has potential as an anti-inflammatory drug candidate, and ganglioside GT1b may play a role in the inflammatory process.
        4,000원
        5.
        2012.10 구독 인증기관 무료, 개인회원 유료
        The objective of this study is to investigate the relationship between anaerobic・aerobic exercise intensity and hand steadiness. Based on physiological analysis the conceptual model explaining that both increased anaerobic and aerobic exercise intensity reduce hand steadiness is suggested, which is verified through the experiment with 20 subjects. Hand steadiness is the critical contributor to having an effect on the job performance just as in the rifle shooting and archery in sports, and the microscope-related job requiring hand steadiness in industries, and so forth. In anaerobic exercise experiment the hand steadiness is measured through hand steadiness tester having 9 different diameter holes after each subject exerts 25%, 50%, 75%, and 100% of maximum back strength measured by back muscle dynamometer. In aerobic exercise condition after they do jumping jack, it is evaluated at each time heart rate reaches 115%, 130%, and 145% of reference heart rate measured in no exercise. The findings are that an increased intensity in both types of exercises tend to decrease hand steadiness, but hand steadiness at 25% of maximum back strength and 115% of reference heart rate is rather higher than at no exercise. Just as the association between cognitive stress and job performance has upside-down U form, so does the relation of physical loading to hand steadiness, which means that a little exercise has a tendency to improve hand steadiness compared to one in no exercise condition .
        4,000원
        6.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this paper is to suggest the strategical lifting postures able to alleviate imbalanced EMG amplitude leading to an increase in low back muscle fatigue while lifting asymmetric load dynamically. Eleven male subjects are required to lift symm
        4,000원
        7.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is aimed to show that an asymmetric load in the frontal plane leads to an increase in low back loading and fatigue in comparison with a symmetric load when workers lift an external weight by investigating previous studies and verifying the phen
        4,000원
        8.
        2012.06 구독 인증기관·개인회원 무료
        The coupling of autophagy and endoplasmic reticulum (ER) stress has been implicated in a variety of biological processes. However, little is known regarding the involvement of the autophagy/ER stress pathway in early embryogenesis or the underlying mechanism (s). Here, we showed that the developmental competence of in vitro-produced (IVP) bovine embryos was highly dependent on the autophagy/ER stress balance. Although relative abundances of autophagy-associated gene transcripts, including LC3, Atg5, and Atg7 transcripts, were high in oocytes and throughout the early stages of preattachment development, extensive autophagosome formation was only detected in fertilized embryos. Using inducer and inhibitor of autophagy, we showed that transient elevation of autophagic activity during early preattachment development greatly increased the blastocyst development rate, trophectoderm cell numbers, and blastomere survival; these same parameters were reduced by both inhibition and prolonged induction of autophagy. Interestingly, the induction of autophagy reduced ER stress and associated damage, while the developmental defects in autophagy-inhibited embryos were significantly alleviated by ER stress inhibitor treatment, indicating that autophagy is a negative regulator of ER stress inearly embryos. Collectively, these results suggest that early embryo genesis of IVP bovine embryos depends on an appropriate balance between autophagy and ER stress. These findings may increase our understanding of important early developmental events by providing compelling evidence concerning the tight association between autophagy and ER stress, and may contribute to the development of strategies for the production of IVP bovine blastocysts with high developmental competence.
        9.
        2012.06 구독 인증기관·개인회원 무료
        Autophagy is known to be involved in a variety of biological processes. However, relatively a little is known regarding oocyte maturation and preimplantation development in mammals. Thus, the current study was conducted to investigate the role of autophagy in oocyte maturation and subsequent preimplantation development in pigs. Porcine oocytes were matured in the presence or absence of 1 μM rapamycin, an autophagy inducing agent, fertilized in vitro, and cultured to blastocyst stage. From Western blotting analysis, we found that active form LC3 was detected during in vitro maturation (IVM) period, suggesting the possible role of autophagy in oocyte maturation. Interestingly, treatment of rapamycin during IVM significantly increased nuclear maturation compared to control group. Importantly, rapamycin-assisted IVM greatly improved monospermic fertilization and blastocyst development rates compared to control embryos. In addition, we also found that cell number and blastomere survival in blastocysts were markedly increased in rapamycin treatment group, which was further evidenced by both elevation of anti-apoptotic transcript Bcl-XL and decrease of pro-apoptotic transcript Bax. Collectively, these results strongly suggest that induction of autophagy may contribute to the completion of nuclear and cytoplasmic maturation of porcine oocytes.
        10.
        2011.10 구독 인증기관·개인회원 무료
        Despite of the presence of estradiol-17β (E2) in ovarian follicles, its role(s) in in vitro maturation (IVM) is still largely unknown, especially in pigs. Thus, the current study was conducted to investigate the effect of E2 on in vitro maturation (IVM) of porcine oocytes and subsequent preimplantation development using in vitro fertilization (IVF)- or somatic cell nuclear transfer (SCNT)-derived embryos. To define the effects of E2 on IVM and early embryogenesis, porcine oocytes were matured in the presence or absence of E2, fertilized in vitro and cultivated to blastocyst stage. Compared to control group, the production of MII oocytes was significantly increased by treatment with E2, accompanying with the increase in MPF content and ERK phosphorylation, and monospermic fertilization and blastocyst development rates were also greatly elevated in the E2-treated oocytes. In addition, the advantageous role of E2 was also found in blastomere survival, which was further evidenced by both elevation of anti-apoptotic transcript Bcl-XL and decrease of pro-apoptotic transcript Bax. Furthremore, these positive effects of E2 were highly reproducible in early development of SCNT embryos. Collectively, the current study strongly suggests that E2 can be used as a efficient IVM supplement leading to successful nuclear/cytoplasmic maturatioin in pigs.
        11.
        2011.10 구독 인증기관·개인회원 무료
        Successful early embryogenesis of somatic cell nuclear transfer (SCNT) embryos is very important to produce cloned animals. However, poor preimplantation development of SCNT embryos has been a major obstacle to the generation of cloned animals due to a lack of understanding of developmental events and underlying mechanism(s). In the current study, we show that production of SCNT embryos with high developmental competence is dependent on the fusion method. Electrofusion causes spontaneous egg activation, accompanied by an increase in intracellular Ca2+ and improper nuclear remodeling, whereas Sendai virus (SV)-mediated fusion greatly reduces these events. In addition, SV-SCNT increased the blastocyst development rate and trophectoderm cell number compared to electrofusion-mediated SCNT (E-SCNT). In particular, expression of ER stress-associated genes and blastomere apoptosis were significantly increased in E-SCNT embryos, which could be alleviated by inhibition of ER stress or by using the SV-mediated fusion method. Taken together, these results strongly suggest that SV is a useful fusion material for improvement of preimplantation development of SCNT embryos through reduction of ER stress-associated apoptosis.
        14.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        전문가시스템의 성공을 좌우하는 지식추출은 주요 애로공정 중의 하나로 알려져 있다. 설상가상으로 전문가의 부재, 새로운 또는 복잡한 문제 등 영역의 특성상 전문가시스템 개발은 실패할 수 있다. 이러한 문제점을 극복하기 위하여 본 논문에서는 KACE 구조를 제안하였다. 본 구조는 작업 발생기, 작업 실행기, 작업 평가기, 규칙 발생기와 전문가시스템 등 5개의 주요 요소로 구성되어 있다. 이 구조를 이용하여 NP-complete인 일정계획 문제에 대한 전문가
        4,000원
        15.
        2008.11 구독 인증기관 무료, 개인회원 유료
        전문가시스템의 성공을 좌우하는 지식추출은 주요 애로공정 중의 하나로 알려져 있다. 설상가상으로 전문가의 부재, 새로운 또는 복잡한 문제 등 영역의 특성상 전문가시스템 개발은 실패할 수 있다. 이러한 문제점을 극복하기 위하여 본 논문에서는 KACE구조를 제안하였다. 본 구조는 작업 발생기, 작업 실행기, 작업 평가기, 규칙 발생기와 전문가시스템 등 5개의 주요 요소로 구성되어 있다. 이 구조를 이용하여 NP-complete인 일정계획 문제에 대한 전문가시스템이 어떻게 구축될 수 있는가를 예시하였다.
        4,000원
        16.
        2007.09 구독 인증기관 무료, 개인회원 유료
        본 연구는 소 배반포의 내부 세포괴로부터 다능성(pluripotency)을 지닌 배아 줄기 세포(embryonic stem cell) 또는 그 유사 세포를 분리 및 배양함으로써 줄기 세포 관련 분야의 기반 기술을 확립하고자 하였다. 소 체외수정란을 10~12일간 체외배양하여 생산된 부화 배반포를 세포분열이 불활성화된 생쥐 태아 섬유아 세포(mouse embryonic fibroblast, MEF) 위에서 배양하여 콜로니 형성을 유도하였으며, 이들로부터 내부 세포괴 유래의 형태를 지닌 것만을 광학현미경 하에서 물리적으로 분리하여 약 5~7일 간격으로 계대배양을 실시하였다. 이러한 방법을 통하여 배아 줄기 유사 세포의 특성을 40계대 이상 유지하는 2개의 세포주를 확립하였다. 각각의 세포주들은 높은 alkaline phosphatase(AP) 활성을 지니고 있었으며, 형광 면역 염색법과 PCR 기법을 사용하여 Oct-4, Nanog, STAT3, SSEA3 및 SSEA4의 발현을 관찰할 수 있었다. 이러한 결과를 종합하여 볼 때 ,본 연구에서는 소 배반포로부터 배아 줄기 세포주를 확립하는 제반 기술이 확립되었다고 판단되며, 향후 관련 분야 연구에 활용될 수 있을 것으로 기대된다.
        4,000원
        19.
        2003.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This research deals with an object-oriented task description(OOTD) method to solve problems such as being hard to understand and a lack of description in existing task description methods. The OOTD method includes an object-oriented task structure diagram
        4,000원
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