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        검색결과 1,644

        581.
        2011.12 구독 인증기관 무료, 개인회원 유료
        Endocrine disrupting chemicals (EDCs) have detrimental effects on human health. Among these EDCs, bisphenol A (BPA) binds to estrogen receptors (ERs) to stimulate estrogen-mediated responses. BPA is assumed to disrupt the reproductive and developmental system of humans. In addition, BPA has recently been suspected as a risk of carcinogenesis. Because BPA can cause abnormal estrogen-mediated response in the organism, exposure to BPA may stimulate growth of estrogen-dependent breast cancers in human. In breast cancer, cyclin E and cyclin-dependent kinase inhibitor p27 are important in G1/S phase transition during cell cycle progression. In this study, using an MTT assay, we investigated the effect of BPA on proliferation of MCF-7 breast cancer cells in vitro. In addition, we also analyzed the transcriptional levels of cyclin E and p27 following treatment with BPA using semi-quantitative RT-PCR. As a result, treatment with BPA resulted in significant induction of breast cancer cell growth, compared to a vehicle. BPA caused alterations of cyclin E and p27 mRNA expression. Expression of cyclin E was increased by BPA, while p27 was decreased at 24 h after treatment with BPA in MCF-7 breast cancer cells. Taken together, these collective results suggest that exposure to BPA induced breast cancer cell proliferation with deregulation of the cell cycle. A further study is required in order to determine the effects of BPA on the carcinogenic process in in vivo models.
        4,000원
        582.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A voltammetric assay of phenol ions was investigated using three electrode systems of graphite pencil working, reference and counter electrodes. Under optimum analytical parameters, square wave stripping working ranges were attained at a mili range of 10~80 mg/L and a micro range of 20~90 ug/L using seawater electrolyte. The developed sensor was applied to tap water and the human body system of a smoker. It was found that the methods can be applied to in vivo fluid or medicinal diagnosis.
        4,000원
        583.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Human resource theories of becoming entrepreneurs or self-employed rather than finding employment are compared as applied to fit the occupational data of technological entrepreneurs and technology jobs. The human capital theory posits that technological e
        4,000원
        584.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Job stress weakens physical ability causing the diseases related to working condition, decreases a production level, and increases mistakes and accidents. This study examined the relationship between job stress and human error, and focused on the moderating effect of age and maintenance type on the relationship between job stress and human error. The study used a quantitative design based on the 450 questionnaires of maintenance personnel in the Air force. The results of multiple regression analysis showed that physiological and psychological stress responses have positively related with human error. In moderating effect test, age appeared to impact on the relationship between physiological/behavioral stress and human error.
        4,000원
        586.
        2011.11 구독 인증기관 무료, 개인회원 유료
        This paper reviewed the relationship between job stress and human error, and the moderating effect of age and maintenance type on the relationship between job stress and human error in maintenance personnel. Based on the responses from 450 maintenance personnels, the results of multiple regression analysis showed that physiological and psychological stress responses have positively related with human error. In moderating effect test, age appeared to impact on the relationship between physiological/behavioral stress and human error.
        4,200원
        587.
        2011.11 구독 인증기관·개인회원 무료
        The aim of this study was to investigate the antitumor activity of solvent fractions from Auricularia auricula-judae 70% ethanol extract and confirmed the active components of dichloromethane fraction showing a potent antitumor activity than other fractions in the broncheoalveolar and gastric cancer cells. The solvent fractions of Auricularia auricula-judae extract, inhibited the growth proliferation of tumor cells in dose-dependent manner. The principle components of dichloromethane fraction were 5,11,17,23-tetrakis (1,1-dimethyl)-28-methoxypentacyclo [19.3.1.1 (3,7).1 (… (65.85%) and diazane (6.17%). The antitumor active components, diazane and gibberellic acid (GA3) were identified in this fraction by GC-MS analysis and lower antitumor activities than dichloromethane fraction. The unknown components of dichloromethane fraction were responsible for its cytotoxic effects on tumor cells. Based on IC50 value, gibberellic acid was little cytotoxic itself. According to PCR amplification, the apoptosis of tumor cells were induced by the down-regulation of Bcl-2 and over-expression of P53 on the presence of solvent fractions, diazane and gibberellic acid. Thus, these findings suggest that the dichloromethane might be used as functional feed additive that suppress the tumor growth in the body than other solvent fractions of Auricularia auricula-judae extracts.
        588.
        2011.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We investigated the inhibitory effects of solvent extracts from Ailanthus altissima in A549 human lung cancer cell. A. altissima has been recognized as a traditional healthy food due to its various biological activities against hypertension, strokes, fever, pain, neuralgia, inflammation, and cancer effects. Recently, it has been reported that the extracts of various wild vegetables show strong anti-cancer properties by induction of apoptosis. However, the mechanisms of their cytotoxicity in human lung cancer cells have been poorly understood. The present study was investigated the effects of solvent extracts from A. altissima on cell growth and apoptosis on A549 human lung cancer cells. A treatment of A. altissima inhibited the growth of A549 cells in a dose-dependent manner by inducing apoptosis. Especially, the chloroform fraction showed the highest anti-cancer effect among five kinds of fractions. And also, induction of apoptosis by chloroform fraction were associated with down-regulation of Bcl-2, and up-regulation of pro-apoptotic Bax expression. From these results, A. altissima may have a therapeutic potential in human lung cancer cells and as a functional food.
        4,000원
        589.
        2011.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        For investigate intracellular function and role of genes in the biological processes, various gene delivery methods into cell have been developed. Many studies performed to construct optimum conditions of gene delivery into cells and tissues. In this study, we examined efficiency of gene delivery-complexed with cationic lipid vector in human cancer cell lines. GFP plasmids were complexed with cationic lipid and transfected into human cancer cell lines at different concentrations. And then, expression of GFP was analysed with fluorescent microscope and FACS. To determine efficiency of gene delivery, we investigated GFP expression level in various cancer cell lines. GFP expression cells were not shown in hepatocellular carcinoma cell line HepG2 and lung carcimona cell line A549 after 24hr transfection, while, GFP expression cells were observed at 500ng concentration after 48hr transfection. In colorectal carcinoma cell line HCT116, GFP expression cells were observed at 100ng and 500ng concentrations after 24hr transfection and slightly increased at 48hr. After transfection into ovary adenocarcinoma cell line SKOV3, we could found that many cells expressed GFP at 500ng concentration after 24hr and highly elevated GFP expression cells after 48hr. For further evaluate gene expression level, we confirmed GFP expression level by using FACS analysis after 48hr transfection. As a result, HepG2 was expressed GFP in very low level at 10ng, 100ng, and 500ng concentrations. We also identified that GFP was expressed low level at 10ng and 100ng in HCT116 and A549, but highly increased at 500ng concentration to 14.19% and 16.57%, respectively. In case of SKOV3, GFP expression was highly elevated to 13.14% at 100ng and 58.10% at 500ng compared with 10ng transfection. By Comparing efficiency of gene expression among cancer cell lines, GFP expression was similar with cell lines at 10ng transfection, but significantly differed from cell lines at 500ng higher concentration. Additionally, GFP expression level of SKOV3 was showed about 10 fold higher than HepG2, and about 4 fold higher than HCT116 and A549 at 500ng. These results demonstrated that efficiency of gene delivery-complexed with cationic lipid vector was the highest in SKOV3, while HepG2 was showed the lowest efficiency. Taken together, we could determined that efficiency of gene delivery into cells differed from each human cancer cell lines. Our study suggest that cellular properties should be considered in gene delivery-complexed with cationic lipid vector to improve cellular expression efficiency of gene.
        4,300원
        590.
        2011.10 구독 인증기관·개인회원 무료
        Urokinas type plasminogen activator (uPA) has been used as a therapeutic agent for treating human diseases such as thrombosis. Attempts to transgenically overexpress the uPA in animal bioreactors have been hampered due to side effects associated with this functional protein hormone on homeostasis. Recently, chicken has been emerged as a potential candidate for use as bioreactor to produce proteins of pharmaceutical importance. Since this species has low homology uPA sequence with mammals, we hypothesized that chicken could be used as a potential bioreactor for production of human uPA. In this study, using replication‐defective Murine Leukemia Virus (MLV)‐based retrovirus vectors encapsidated with Vesicular Stomatitis Virus G Glycoprotein (VSV‐G), we attempted to make transgenic chicken expressing human uPA (huPA). The recombinant retrovirus was injected beneath the blastoderm of non‐incubated chicken embryos (stage X, at laying). After 21 days of incubation (at hatching), all of the 38 living chicks that assayed, were found to express the vector‐encoded huPA gene in various organs and tissues, which was under the control of the Rous Sarcoma Virus (RSV) or Cytomegalovirus (CMV) promoter. Using specific primer set for huPA, PCR and RTPCR analyses of gDNA isolated from these samples demonstrated these chickens were transgenic for huPA. Furthermore, successful germ line transmission of huPA transgene was confirmed and next generation whole body huPA transgenic chickens were also produced. We also assayed huPA protein titer in blood (17.1 IU/ml) and eggs (4.4 IU/ml) of whole body huPA transgenic chicken. Thus, our results demonstrated that chicken could be used as bioreactors to produce huPA.
        591.
        2011.10 구독 인증기관·개인회원 무료
        The production of transgenic animals using somatic cell nuclear transfer (SCNT) has been widely described. A critical problem in the production of transgenic animals is the uncontrolled constitutive expression of the foreign gene which occasionally results in serious physiological disorders in the transgenic animal. In this study, we designed three different expression vectors that express the hEPO gene. hEPO is a hormone produced by the kidney that promotes the formation of red blood cells by the bone marrow. For the in vitro production of transgenic embryos, the different expression vectors were transduced into holstein ear fibroblast cells, respectively, and GFP expressed donor cells were transferred into enucleated oocytes, and then the reconstructed SCNT embryos were developed into pre-implantation stage. From three replicates, GFP expressed 112 transgenic SCNT embryos were produced. When their cleavage rate and blastocyst rate were compared with non-transgenic SCNT embryos, the results were presented into 73.2% vs. 76.9% and 26.8% vs. 30.6%, respectively, there were no differences. Also, total cell number and ICM cell numbers of day 8 blastocysts were statistically not different between the transgenic SCNT groups (120.6±7.9 and 31.4±8.2) and control SCNT group (128.3±4.8 and 35.3±4.0). The GFP expression levels were presented consecutively high during the culture of transgenic SCNT embryos. By analysis of semi-quantitative RT-PCR, the relative expression levels of hEPO mRNA and pluripotent gene were determined. These results demonstrated that the hEPO expressed transgenic bovine embryos can be efficiently produced in vitro by SCNT technique, while their potential of cloned animal production have to be examined in further study.
        592.
        2011.10 구독 인증기관·개인회원 무료
        Stem cell therapy is undoubtedly the most promising therapeutic approach for neurological disorders. Adipose tissue is ubiquitous and it can be easily harvested in large quantities under local anesthesia with little patient discomfort, making adipose tissue into the ideal large-scale source for research on clinical applications. In this study we monitored the neuronal cell differentiation potential of human adipocyte in the following condition; i) N2 medium containing 200 uM ascorbic acid (AA) and/or 10 uM flavonoid (F) and ⅱ) N2 medium containing AA and/or 10 ng/ml brain derived neurotrophic factor (BDNF) and/or, 200 ng/ml sonic hedgehog (SHH) plus 100 ng/ml fibroblast growth factor (FGF) 8. Adipose stem cells were cultured in above described differentiation condition for three weeks. RT-PCR analysis demonstrated that the mRNA levels of neuronal cell markers in differentiated adipose stem cells. Under the culture condition using N2 medium containing AA, the expression level of nestin (neural progenitor marker) m- RNA was high in all groups, while those of Neuro D, and LEP and FABP4 (adipocyte marker) mRNA were significantly decreased. Also, the addition of BDNF or SHH+FGF8 in N2 medium containing AA enhanced the neural cell differentiation from adipose stem cells, the expression level of Map2 (mature neuron) mRNA was increased, and that of TH (dopaminergic neuron marker) mRNA was high. In addition, we confirmed that the flavonoid addition has effect on the increase of Map2 expression. These results demonstrate that our designed culture condition has effect on the neural cell differentiation of adipose stem cells and this stimulatory effect may be further enhanced by transplantation.
        593.
        2011.10 구독 인증기관·개인회원 무료
        The generation of patient-specific pluripotent stem cells has the potential to accelerate the implementation of stem cells for clinical treatment of degenerative diseases. This study was to examine the in vitro neuron cell differentiation characteristics of our established human (h) iPS cells (IMR90-iPS-1~2) derived from human somatic cells. For the neuron differentiation, well grown hiPS colonies were recovered by collagenase treatment and then suspended cultured in a non-adherent bacteriological culture dish using human embryonic stem (hES) cell culture medium for 4 days. Embryoid bodies were plated and cultured in serum-free ITSFN (insulin/transferrin/selenium/fibronectin) medium for 8 days to select neural precursor cells. Then selected neuronal cells were dissociated, plated onto poly-L-ornithin/laminin coated dish at a concentration of 2 x 105 cells/cm2 and expanded in N2 medium containing 20 ng/ml bFGF, 200 ng/ml SHH and 100 ng/ml FGF-8 for 7 days. For the final differentiation step involved removing agents and culturing for 14 days in 20 ng/ml BDNF added N2 medium. In the neural precursor stage, >90% of nestin positive cells and >50% NCAM positive cells were obtained. Also, in final differentiation step, we confirmed the high percent (>80%) of mature neuron tubulin-β positive cells and approximately >20% of tyrosine hydroxylase positive cells. Also, these results were confirmed by RT-PCR. These results indicated that hiPS cells have potential to generate specific neuron differentiation and especially TH+ neuron was also can be obtained, and thus hiPS-derived neural cells might be an usable source for the study of neuro-degenerative disease.
        594.
        2011.10 구독 인증기관·개인회원 무료
        Several human leukocyte subsets including natural killer (NK) cells, cytotoxic T lymphocytes (CTL), and polymorphonuclear neutrophils (PMN) participate in cellular immune responses directed against vascularized pig-to-human xenografts. As these leukocytes express the death receptor Fas either constitutively (PMN) or upon activation (NK, CTL), we explored in vitro whether the transgenic expression of membrane-bound human Fas ligand (mFasL) on porcine fetal fibroblasts is a valuable strategy to protect porcine xenografts. cDNA of mFasL carrying the deletion at the cleavage site with metalloproteinase and lacking the death domain in its cytoplasmic tail was subcloned into pCAGGS expression vector driven by the chicken β-actin promoter containing blastidin- resistance cassette. The mFasL expression vector was transfected into mini-pig fetal fibroblasts by lipofection method. Blastidin-resistant cells were screened by PCR and FISH. The expression of mFasL was confirmed by Western blot and FACS with the mouse anti-human FasL antibody. Interaction of two transgenic clonal cell lines with human leukocytes was analyzed using functional assay for cytotoxicity. mFasL expressed on porcine fetal fibroblasts protected porcine fetal fibroblasts against killing mediated by human NK cells. The rate of NK cell mediated cytotoxicity was significantly reduced in transgenic clonal cells (54±10.80%) compared to normal minipig fetal fibroblasts. This result indicated that grafts of transgenic pigs expressing mFasL could control the cellular immune response to xenografts, and create a window of opportunity to facilitate xenograft survival.
        595.
        2011.10 구독 인증기관·개인회원 무료
        Pigs may be considered as a suitable organ source for its characteristics in xenotransplantation if significant immunological barriers can be overcome. However, xenograft could be rejected by T cells, especially CD8+ cytotoxic T lymphocytes (CTL)-mediated response, because these elements show great cytotoxicity against xenograft by recognizing Swine Leukocyte Antigen (SLA)-I. Human cytomegalovirus (HCMV) encodes unique short (US) 11 gene, which interferes with cellular immune responses by inducing rapid degradation of newly synthesized heavy chains (HC) of MHC class I from endoplasmic reticulum (ER) to the cytosol. In this study we established two US11 clonal cell lines by transfection into minipig fetal fibroblasts and confirmed the integration of US11 gene by PCR and FISH. The reduction of Swine Leukocyte Antigen (SLA)-I which was expressed on the cell surface by US11 was also detected by flow cytometry assay. The level (14.6 % to 21.2%) of SLA-I expression in US11 clonal cell lines was decreased relative to the control. The reconstructed embryos were produced with these clonal cells and transferred to nine surrogate gilts. Ultrasound examination of recipient surrogates on days 35 after embryo transfer confirmed established pregnancies in two recipients. One recipient delivered one piglet with normal birth weight. PCR analysis revealed that transgene vector was integrated in the offspring genome. Transgene-expression analysis and CTL assay are currently underway. The present results show that transgenic pig was produced with US11 cDNA for controlling cell-mediated rejection. This result indicated that grafts of transgenic pigs expressing human cytomegalovirus protein US11 could control the cellular immune response to xenografts, and create a window of opportunity to facilitate xenograft survival. This research was supported by the BioGreen 21 Program (#20110301-061-541- 001-05-00), Rural Development Administration, Republic of Korea.
        596.
        2011.10 구독 인증기관·개인회원 무료
        The vast majority of embryo generated by Assisted Reproductive Technologies (ART) do not result in a live offspring and a multiple birth is the single biggest health risk associated with human fertility treatment, and the used of frozen embryos increased for medical or personal reasons. However, practical and ethical reasons might hamper study of human embryos. Therefore, animal models are necessary to elucidate the molecular and morphological changes during development. In the serial experiments, we employed mouse embryos and a Cdx-inducible ES cell system that transdifferentiates into TS cells. We found aberrant gene expression profiles including apoptosis associated (Bcl2), lineage formation related genes (Cdx-2, Tcfap2c, Oct4, and Nanog), and/or mitochondrial DNA replication related genes (mt-cox-1, mt-cox-2, Polg, Polg2, Tfam) in mouse embryos that showed developmentally retardation between morula to blastocyst transition or post implantation development after embryo transfer to surrogate mothers, compared to control embryos. To determine direct interaction between knockdown genes via siRNA approach and putative down-stream genes involved in blastocyst formation and further development, we carried out qPCR and Chip assay in either mouse embryos or the ES cells. qPCR and Chip assay results showed target gene directly bound to promoter regions of down-regulated genes in TS cells. In conclusion, we suggested that an increased understanding of epigenetic regulation of early embryonic development through animal models may ultimately lead to better methodologies for selecting more competent embryos and and/or protocols for augmenting embryos viability.
        597.
        2011.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Growing evidence indicates that oxidized low density lipoprotein (LDL) may promote atherogenesis. Therefore, inhibition of LDL oxidation may impede this process. The inhibitory effected on the susceptibility of human LDL to Cu²+ or macrophages induced oxidation was investigated by monitoring thiobarbituric acid reactive substances (TBARS). Organosulfur compounds of garlic oil contains diallyldisulfide, diallyltrisulfide, diallyltetrasulfide, and diallyl pentasulfide in order. Garlic oil inhibited LDL oxidation by Cu²+, or macrophages in a dose dependently, with a 20~60 μg, as increased TBARS assay. Garlic oil, at 60 μM, almost completely inhibited macrophages induced increase in electrophoretic mobility of LDL. When compared with several other antioxidants, probucol showed highest ability,and then garlic oil showed a much higher ability than natural occurring antioxidants, α-tocopherol and ascorbic acid. The results suggested that garlic oil might play the inhibitory effects in the process of LDL oxidation.
        4,000원
        598.
        2011.09 구독 인증기관 무료, 개인회원 유료
        Eugenol (4-allyl-2-methoxyphenol) is a naturally occurring phenolic compound that is widely used in dentistry as a component of zinc oxide eugenol cement that is commonly applied to the mouth environment. Cisplatin is one of the most potent known anticancer agents and shows significant clinical activity against a variety of solid tumors. This study was undertaken to investigate the synergistic apoptotic effects of co-treatments with eugenol and cisplatin on human melanoma (G361) cells. To investigate whether this co-treatment efficiently reduces the viability of G361 cells compared with each single treatment, an MTT assay was conducted. The induction and augmentation of apoptosis were confirmed by DNA electrophoresis, Hoechst staining and an analysis of DNA hypoploidy. Western blot analysis and immunofluorescent staining were also performed to evaluate the expression levels and the translocation of apoptosis-related proteins following this co-treatment. Furthermore, proteasome activity and mitochondrial membrane potential (MMP) changes were also assayed. The results indicated that a co-treatment with eugenol and cisplatin induced multiple pathways and processes associated with an apoptotic response in G361 cells including nuclear condensation, DNA fragmentation, a reduction in MMP and proteasome activity, the increase and decrease of Bax and Bcl-2, a decreased DNA content, the release of cytochrome c into the cytosol, the translocation of AIF and DFF40 (CAD) into the nucleus, and the activation of caspase-9, caspase-7, caspase-3, PARP and DFF45 (ICAD). In contrast, separate treatments of 300 μM eugenol or 3 μM cisplatin for 24 h did not induce apoptosis. Our present data thus suggest that a combination therapy of eugenol and cisplatin is a potential treatment strategy for human melanoma.
        4,000원
        599.
        2011.09 구독 인증기관 무료, 개인회원 유료
        Eugenol is an essential oil found in cloves and cinnamon that is used widely in perfumes. However, the significant anesthetic and sedative effects of this compound have led to its use also in dental procedures. Recently, it was reported that eugenol induces apoptosis in several cancer cell types but the mechanism underlying this effect has remained unknown. In our current study, we examined whether the cytotoxic effects of eugenol upon human melanoma G361 cells are associated with cell cycle arrest and apoptosis using a range of methods including an XTT assay, Hoechst staining, immunocytochemistry, western blotting and flow cytometry. Eugenol treatment was found to decrease the viability of the G361 cells in both a time- and dose-dependent manner. The induction of apoptosis in eugenol-treated G361 cells was confirmed by the appearance of nuclear condensation, the release of both cytochrome c and AIF into the cytosol, the cleavage of PARP and DFF45, and the downregulation of procaspase-3 and -9. With regard to cell cycle arrest, a time-dependent decrease in cyclin A, cyclin D3, cyclin E, cdk2, cdk4, and cdc2 expression was observed in the cells after eugenol treatment. Flow cytometry using a FACScan further demonstrated that eugenol induces a cell cycle arrest at S phase. Our results thus suggest that the inhibition of G361 cell proliferation by eugenol is the result of an apoptotic response and an S phase arrest that is linked to the decreased expression of key cell cycle-related molecules.
        4,000원
        600.
        2011.09 구독 인증기관 무료, 개인회원 유료
        Endothelial cells are a vital constituent of most mammalian organs and are required to maintain the integrity of these tissues. These cells also play a major role in angiogenesis, inflammatory reactions, and in the regulation of thrombosis. Angiogenesis facilitates pulp formation and produces the vessels which are essential for the maintenance of tooth homeostasis. These vessels can also be used in bone and tissue regeneration, and in surgical procedures to place implants or to remove cancerous tissue. Furthermore, endothelial cell regeneration is the most critical component of the tooth generation process. The aim of the present study was to stimulate endothelial regeneration at a site of acute cyclophosphamide (CP)-induced endothelial injury by treatment with human umbilical cord-derived endothelial/mesenchymal stem cells (hEPCs). We randomly assigned 16 to 20-week-old female NOD/SCID mice into three separate groups, a hEPC (1 × 105 cells) transplanted, 300mg/kg CP treated and saline (control) group. The mice were sacrificed on days 5 and 10 and blood was collected via the abdominal aorta for analysis. The alanine transaminase (ALT), aspartate aminotransferase (AST), serum alkaline phosphatase (s-ALP), and albumin (ALB) levels were then evaluated. Tissue sections from the livers and kidneys were stained with hematoxylin and eosin (HE) for microscopic analysis and were subjected to immunohistochemistry to evaluate any changes in the endothelial layer. CP treatment caused a weight reduction after one day. The kidney/body weight ratio increased in the hEPC treated animals compared with the CP only group at 10 days. Moreover, hEPC treatment resulted in reduced s-ALP, AST, ALT levels compared with the CP only group at 10 days. The CP only animals further showed endothelial injuries at five days which were recovered by hEPC treatment at 10 days. The number of CD31-positive cells was increased by hEPC treatment at both 5 and 10 days. In conclusion, the CP-induced disruption of endothelial cells is recovered by hEPC treatment, indicating that hEPC transplantation has potential benefits in the treatment of endothelial damage.
        4,000원