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        검색결과 525

        221.
        2013.10 구독 인증기관·개인회원 무료
        We have identified novel ricin-type (R-type) lectin by sequencing of random clones from cDNA library of the coleopteran beetle, T.molitor. The cDNA sequence is comprised of 495 bp encoding a protein of 164 amino acid residues and shows 49% identity with galectin of Tribolium castaneum. Bioinformatics analysis shows that the amino acid residues from 35 to 162 belong to ricin-type β-trefoil structure. The transcript was significantly upregulated after early hours of injection with peptidoglycans derived from Gram (+) and Gram (-) bacteria, beta-1, 3 glucan from fungi and an intracellular pathogen, L. monocytogenes suggesting putative function in innate immunity.
        224.
        2012.06 구독 인증기관 무료, 개인회원 유료
        The influenza virus is an important respiratory risk affecting humans, and effective treatments are needed. Some oriental medicines are currently applied for treatment of common colds as well as influenza infection. Previous studies have reported that the therapeutic properties of MA-128 are effective for treatment of psoriasis antiasthmatic and atopic dermatitis. In this study, we investigated the therapeutic properties of the novel herbal medicine, MA-128, for treatment of influenza virus infection by oral administration. MA-128 is an active natural biological compound from herbal-marine origin. The results showed that oral administration of MA-128 in mice could confer a survival benefit against Type A influenza virus infection. Daily oral administration of MA-128 resulted in delayed death in infected mice for three days against mouse adapted H3N2 (A/Philippines/2/82). However, it protected more than 60% of mice from lethal infection of 2009 pandemic H1N1 (A/Korea/CJ01/2009) influenza virus. In addition, lung viral titers were significantly reduced at seven days post infection (~100 times) compared with mock-treated mice and viruses were cleared at 9 dpi only in the MA-128 treated groups. This study demonstrated the potential of the novel herbal medicine, MA-128, as an herbal remedy against influenza A viruses.
        4,000원
        225.
        2012.06 구독 인증기관·개인회원 무료
        Hyperacture rejection (HAR) of pig organs, upon xenotransplantation into primates, could partly be overcome by knocking out the alpha-Gal gene. However, xenotransplanted organs may still undergo immunological acture rejection (AR) or acute vascular rejection (AVR). Among several genes involved in AR and AVR, the hCD47 evades the monocyte/ macrophage mediated phagocytosis by identifying the self/non-self signal (CD47-SIRPa) whereas hTFPI participates in the regulation of coagulation pathway by acting upstream of the thrombin. In this study, we investigated hCD47 and hTFPI as two possible candidates for avoiding AR and AVR, respectively upon pig-to-human xenotransplantation. A co-expression vector for hCD47 and hTFPI was constructed using 2A peptides system (F2A) and transfected into the porcine kidney cell line (PK-15). The transfected cells stably expressed both hCD47 and hTFPI mRNA and proteins. Co-culture of non-transfected, hCD47-transfected, hTFPI-transfected or hCD47+hTPFI-transfected PK15 cells with natural killer (NK) cells, monocytes and macrophages confirmed the cytotoxic effect of hCD47 and revealed a synergistic effect of hCD47 and hTFPI co-transfection. There was an attractive survivability of 25~30% on each type of innate immune cell, NK cell and macrophage. These results suggest that transgenic pigs, genetically modified for hCD47 and hTFPI may be useful for overcoming xenograft rejection. Furthermore, cotransfection with hTFPI may enhance the cytotoxic effect of hCD47, possibly by assisting the hCD47-SIRPa binding by an unknown mechanism.
        226.
        2012.06 구독 인증기관·개인회원 무료
        Phosphoprotein Enriched in Astrocytes (PEA15) is a 15kD-sized intracellular signaling protein, highly expressed in astrocytes and constitutively expressed in peripheral tissues. Recently it was found that PEA15 expression was elevated in patients suffering type 2 diabetes and suggested to be involved in the syndrome of insulin resistance. To investigate the functional role of PEA15 for the control of blood glucose level, we produced a transgenic pig over-expressing mouse PEA15 (mPEA15). As a model animal, pig has many advantages. They have a higher fecundity and a short generation time and are physiologically similar to human. Using the transgenic pig, we carried out a series of experiments to establish a link between PEA15 expression and the insulin resistance. Our results suggested that, compared with control pig, mPEA15 pig has, (1) a higher blood resistin level, (2) a lower cell membrane-embeded GLUT4 level, and (3) a lower glucose clearing ability based on oral glucose tolerance test (OGTT). When our results combined, it can be concluded that mPEA15 over-expressing pig has many symptoms of insulin resistance and these pigs will become a useful disease model to investigate diabetes mellitus in the near future.
        227.
        2012.06 구독 인증기관·개인회원 무료
        Polycystic ovarian syndrome (PCOS) is a heterogeneous syndrome associated with follicle growth arrest, dysregulated sex hormone profile, hyperthecosis and insulin resistance. Chemerin, a novel adipokine, is associated with obesity and metabolic syndrome. Although obese women and in PCOS subjects have elevated plasma chemerin levels, whether and how chemerin is involved in the regulation of follicular growth/steroidogenesis and pathogenesis of PCOS is unknown. Our objective is to better understand the complex regulatory mechanisms involved in the control of these processes and gain insights in their dysregulation in the pathogenesis of PCOS. We hypothesize that: (a) hyperandrogenism induces small and medium antral follicle growth arrest and ovarian structural changes, resulting from granulosa cell and oocyte apoptosis and theca cell survival, and (b) chemerin regulates follicular growth and steroidogenesis and contributes to the pathogenesis of PCOS. Using immature rats (day 13~15 for follicle culture and day 21~24 for granulosa cells culture) and a chronically androgenized rat model [dihydrotestosterone (DHT); 83 μg daily, day 21~105] which recapitulates the reproductive and metabolic phenotypes of human PCOS, we have examined the granulosa cell expression patterns of chemerin and its receptor CMKLR1 and their steroidogenic and follicle growth capability. DHT treatment resulted in decreased follicle numbers in preantral to preovulatory stages and absence of corpus luteum, but increased numbers of condensed atypical follicles. Atypical follicles, constituted predominantly of theca cells, exhibited high expression of calpain and down‐regulation of the cytoskeletal protein substrates vimentin, fodrin and β‐tubulin. Granulosa cell aromatase expression was significantly down‐regulated, a response accompanied by increased activated caspase‐3 content and DNA fragmentation. While PTEN levels were considerably higher in granulosa cells in the PCOS rats than controls, phospho‐Akt (Ser473) content was lower. In addition, DHT also activated granulosa cell caspase‐3, decreased XIAP, PARP and phospho‐Akt contents and induced apoptosis in vitro, responses that could be attenuated by forced expression of XIAP. These findings are consistent with our hypothesis that dysregulated follicular growth in PCOS is associated with changes in follicular growth dynamics and follicle cell fate, a consequence of dysregulated interactions of pro‐survival (p‐Akt, XIAP, PARP) and proapoptotic (calpain, PTEN, caspase‐3) modulators in a cell‐specific manner. Chemerin and CMKLR1 were expressed in granulosa cells and negatively regulated by gonadotropin in vivo and in vitro. Serum and ovarian chemerin levels in DHT‐treated rats were elevated, and associated with arrested early antral follicular growth, remodeling of the follicle wall and decreased expression of p450 side‐chain cleavage enzyme (p450- scc), aromatase and hydroxysteroid dehydrogenases. Recombinant chemerin inhibited FSH ‐ induced estradiol secretion in granulosa cells from DHT‐treated rats in vitro. Chemerin also suppressed basal and FSH‐ and GDF9‐induced follicle growth and estradiol/ progesterone production in preantral follicle cultures. Moreover, chemerin suppressed FSH‐induced p450scc/aromatase expression and progesterone/estradiol secretion in immature rat granulosa cells in vitro. These studies demonstrate that chemerin is a novel negative regulator in FSH‐induced follicular growth and steroidogenesis and support the notion that the dysregulation of chemerin expression and function contributes to pathogenesis of PCOS. Our observations also suggest that this chronically androgenized rat model may be useful not only for studies on the long term effects of androgen on folliculogenesis, but also on the pathophysiology of PCOS. * This work was supported by grants from the Canadian Institutes of Health Research (CIHR; MOP‐119381) and the World Class University (WCU) program through the Ministry of Education, Science and Technology funded by the National Research Foundation of Korea (R31‐10056).
        228.
        2012.05 구독 인증기관·개인회원 무료
        In the process of revising the tachinid subgenus Linnaemya Robineau-Desvoidy of South Korea, three species are recognized as new to the country: Linnaemya pallidohirta Chao, L. scutellaris (Malloch) and L. lateralis (Townsend). They belong to the oralis species group of the subgenus. L. scutellaris (Malloch) and L. lateralis very closely resemble each other so that they need to be identified with caution. We here provide detailed redescriptions and illustrations with their diagnostic characters indicated.
        231.
        2011.12 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to determine the effect of macrophages on growth of human colon cancer cells. The results showed that co-culture of colon cancer cells with macrophages inhibited the growth of colon cancer cells (HCT116 and SW620) depending on the number of macrophages, RAW 264.7 cells, and activated THP-1 cells accompanied by down regulation of pSTAT3 in cancer cells. We also found that expression and release of cancer cell growth inhibitory cytokines, IL-1 receptor antagonist (IL-1ra) and IL-10, was increased in macrophages. Blocking of the STAT3 pathway with specific inhibitor and siRNA of STAT3 abolished the growth of colon cancer cells and expression of IL-1ra and IL-10. In addition, neutralization of IL-1ra and IL-10 with antibodies resulted in reversal of macrophage-induced inhibition of cancer cell growth. These data showed that IL-1ra and IL-10 released from macrophages inhibit growth of colon cancer cells through inhibition of the STAT3 pathway.
        4,500원
        236.
        2011.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        To perform imaging observations of optically red objects such as high redshift quasars and brown dwarfs, the Center for the Exploration of the Origin of the Universe (CEOU) recently developed an optical CCD camera, Camera for QUasars in EArly uNiverse (CQUEAN), which is sensitive at 0.7-1.1 μm. To enable observations with long exposures, we develop an auto-guiding system for CQUEAN. This system consists of an off-axis mirror, a baffle, a CCD camera, a motor and a differential decelerator. To increase the number of available guiding stars, we design a rotating mechanism for the off-axis guiding camera. The guiding field can be scanned along the 10 arcmin ring offset from the optical axis of the telescope. Combined with the auto-guiding software of the McDonald Observatory, we confirm that a stable image can be obtained with an exposure time as long as 1200 seconds.
        4,000원
        237.
        2011.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present results of two-color VR photometry of the intermediate polar RXS J1803. The data were aquired using the Korean 1-m telescope located at Mt. Lemmon, USA. Different "high" and "low" luminosity states, similar to other intermediate polars, were discovered. No statistically significant variability of the color index with varying luminosity was detected. The orbital variability was found to be not statistically significant. Spin maxima timings were determined, as well as the photometric ephemeris for the time interval of our observations. The spin period variations, caused by interaction of the accretion structure with the rotating magnetic white dwarf, were also detected. These variations are of complicated character, and their study requires further observations. We determine the color transformation coefficients for our photometric systems, and improve on the secondary photometric standards.
        4,000원
        238.
        2011.06 구독 인증기관 무료, 개인회원 유료
        In all living organisms, respiration may lead to oxidative stress, a state where increased formation of reactive oxygen species overwhelms host protection and subsequently induces DNA damage, lipid peroxidation, and protein denaturation. As a phenolic acid, chlorogenic acid occurs ubiquitously in food. It has been proven to have a number of biological effects in vitro and in vivo, including antioxidant, anti-inflammatory, and anticarcinogenic properties. Therefore, to some extent, chlorogenic acid can promote human health, and hopefully provide new methods for treatment of chronic disease. Recent studies have focused on the antioxidant properties of dietary polyphenols. The in vitro data often conflict with results obtained from in vivo studies on the antioxidant capacity of plasma or the resistance of plasma and lipoproteins to oxidation ex vivo after consumption of polyphenol-rich foods by human subjects. These inconsistencies are likely explained by the limited bioavailability of dietary polyphenols and their extensive metabolism in humans. Polyphenols exert multifaceted actions, and any clinical application using these substances should be based on a precise understanding of the physiologically relevant mechanisms.
        4,000원
        239.
        2011.06 구독 인증기관 무료, 개인회원 유료
        The dissemination process of agricultural research and development (R&D) results has somewhat different characteristics from that of typical R&D results. However, these characteristics are not adequately considered on the basis of an examination of the current performance system, the resulting management plans, and strategies for the application and dissemination of the results of agricultural R&D in Korea. The performance evaluation indicator exposed the problem of the inadequate consideration of the characteristics of each of these areas, particularly the lack of unified R&D-related institutions and the inadequacy of the system to monitor outcomes. To address these shortcomings in the agricultural R&D programs in Korea, the policies pertaining to agricultural R&D performance, results management, and dissemination in the U.S. and Japan were examined. Based on these investigations, we proposed strategies to improve the agricultural R&D policies in Korea.
        6,900원
        240.
        2011.06 구독 인증기관 무료, 개인회원 유료
        This study describes the development of a web-based system that collects all data generated in the research conducted to set pre-harvest residue limits (PHRLs) for agricultural product safety control. These data, including concentrations of pesticide residues, limit of detection, limit of quantitation, recoveries, weather charts, and growth rates, are incorporated into a database, a regression analysis of the data is performed using statistical techniques, and the PHRL for an agricultural product is automatically computed. The development and establishment of this system increased the efficiency and improved the reliability of the research in this area by standardizing the data and maintaining its accuracy without temporal or spatial limitations. The system permits automatic computation of the PHRL and a quick review of the goodness of fit of the regression model. By building and analyzing a database, it also allows data accumulated over the last 10 years to be utilized.
        6,600원