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        검색결과 31

        1.
        2019.03 구독 인증기관 무료, 개인회원 유료
        The arrest of Meng Wanzhou, CFO of international telecom giant Huawei Technologies, have fired up political and diplomatic commotions around the world. Meng’s arrest in Vancouver based on several indictment charges accused by the US government against Meng particularly situated Canada in a precarious position of standing strong as an ally of the US, but also avoiding needless enragement of China. Because the US filed a formal extradition request to Canada, Canada’s federal Minister of Justice has to determine whether Meng’s extradition hearing will take place, by examining legal prongs under the US-Canada Extradition Treaty. The international communities will be watching closely of this contentious extradition case that will certainly have huge implications on diplomatic, economic and political relationships between the Western world and China.
        3,000원
        2.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        ZAR1은 척추동물의 초기 배아 발달에 영향을 미치는 유전자로 알려져 있다. 본 연구는 두록 수퇘지 112두에서 ZAR1 유전자의 SNP을 발굴하고 ZAR1 유전자의 인트론 Single nucleotide polymorphism(SNP)과 정액의 운동학적 특성들과의 연관성을 규명하였다. 돼지의 정액 운동학적 특성을 분석하기 위해서 운동성(motility, MOT), 직선운동 속도(straight-line velocity, VSL), 곡선운동 속도(curvilinear velocity, VCL), 평균운동 속도(average path velocity, VAP), 직진성(linearity, LIN), 선형성(straightness, STR), 측두 이동거리(amplitude of lateral head displacement, ALH) 및 머리 진동수(beat cross frequency, BCF)를 측정 하였다. SNP을 탐색하기 위해서 돼지의 혈액에서 genomic DNA를 추출하여 PCR(polymerase chain reaction)을 통해 시퀀싱 분석을 하여 유전자형을 분석하였다. 그 결과 ZAR1의 non-coding 영역인 인트론에서 SNP 3개를 확인 했으며 각 각 인트론 2 영역에서 g.2435T>C, 인트론3 영역에서 g.2605G>A, g.4633A>C 변이를 보였다. g.2435T>C, g.2605G>A는 각 각 MOT(p<0.01)와 VSL(p< 0.05)에서 높은 연관성을 나타냈고 g.4633A>C는 MOT, VCL, VSL, VAP, ALH에서 높은 연관성을 나타냈다(p<0.01). 본 연구 에서는 ZAR1 유전자의 SNP이 돼지 정액의 운동학적 특성들에 영향을 미치는 것으로 나타났다. 이러한 결과는 ZAR1이 우수한 수퇘지들에서 번식능력이 높은 개체를 선발할 수 있는 후보유전자로 제시하며 다양한 돼지의 품종과 더 많은 두수를 확보하여 검증연구를 통해 우수한 능력의 수퇘지에서 활력이 좋은 개체를 선발하는 분자마커 연구의 기초자료로 사용이 가능하다.
        4,000원
        3.
        2018.11 구독 인증기관·개인회원 무료
        Thiamethoxam (TMX) is a neonicotinoid insecticide. Residues of TMX have been detected in various crops. Although it has specific high toxicity to insects and is designed to exterminate them, the toxicity has also found in mammals recently. Differ from acetylcholine toxicity, TMX has peroxide toxicity in mammals. Matured oocytes have the capacity of fertilization, but oocytes own abundant mitochondria and its maturation is vulnerable to reactive oxygen species (ROS). Excessive production of reactive oxygen species (ROS) can override antioxidant defenses, produce oxidative stress and DNA damage that triggers apoptosis and necrosis in organisms. However little is known about the harm of ROS induced by TMX during oocytes maturation. Here, bovine germ-vesicle (GV) oocytes were cultured to metaphase of the second meiosis (MII) stage in vitro with or without TMX. During this process, oocytes were evaluated by various methods. Microscopic examination showed that 1.6 mM TMX significantly inhibited the maturation process in which oocytes were arrested before MI stage or between MI and MII stage. Correspond to this two periods, immunofluorescence staining and enzyme activity analysis showed that active CDC25 and CDC2 reduced in TMX group compared to control; time lapse and immunofluorescence staining gave results that Cyclin B could not be degraded, actin cap could not form, and Bub3 could not be removed from kinetochores. In addition, MII oocytes exposed to TMX showed disordered chromosomes and spindle. To study further, oocytes cultured for 24 h were analyzed. On the one hand, these oocytes in TMX group accumulated more ROS and produced significantly decreased mitochondrial membrane potential and increased apoptotic signal compared to control by methods of quantities for dichlorodihydrofluorescein diacetate (DCHFDA), 5,5′,6,6′-Tetrachloro-1,1′,3,3′-tetraethyl-imidacarbocyanine iodide and Annexin-V, but the level of γH2AX protein in TMX group did not decline significantly compared with control. On the another hand, these oocytes were activated to be parthenogenetic embryos and cultured. Assessment for embryo development showed decreased rates of cleavage, morula and blastocyst in TMX group compared to control in vitro. In conclusion, these results suggest that ROS induced by TMX results in dysfunction of mitochondria and apoptosis, which block bovine oocytes to MI stage, trap them at AI/TI stage and trigger disordered chromosomes and spindle at MII stage. Additionally, MII oocytes with poor qualities result from TMX lose abilities to cleavage and develop to be morulae and blastocysts.
        4.
        2018.06 구독 인증기관 무료, 개인회원 유료
        Codium fragile (Suringar) Hariot is an edible green seaweed that belong to the Codiaceae family and has been used in Oriental medicine for the treatment of enterobiasis, dropsy, and dysuria. Methanol extract of codium fragile has anti-oxidant, anti-inflammatory and anti-cancer properties, although the anti-cancer effect on oral cancer has not yet been reported. In this study, we investigated the anti-cancer activity and the mechanism of cell death by methanol extracts of Codium fragile (MeCF) on human FaDu hypopharyngeal squamous carcinoma cells. Our data showed that MeCF inhibits cell viability in a dose-dependent manner, and markedly induced apoptosis, as determined by the MTT assay, Live/Dead assay, and DAPI stain. In addition, MeCF induced the proteolytic cleavage of procaspase -3, -7, -9 and poly(ADP-ribose) polymerase(PARP), and upregulated or downregulated the expression of mitochondrial-apoptosis factor, Bax(pro-apoptotic factor), and Bcl-2(anti-apoptotic factor), . Futhermore, MeCF induced a cell cycle arrest at the G1/S phase through suppressing the expression of the cell cycle cascade proteins, p21, CDK4, CyclinD1, and phospho-Rb. Taken together, these results indicated that MeCF inhibits cell growth, and this inhibition is mediated by caspase- and mitochondrial-dependent apoptotic pathways through cell cycle arrest at the G1/S phase in human FaDu hypopharyngeal squamous carcinoma cells. Therefore, methanol extracts of Codium fragile can be provided as a novel chemotherapeutic drug due to its growth inhibition effects and induction of apoptosis in human oral cancer cells.
        4,000원
        5.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Purpose: The aim of this study was to examine the effect of repeated simulation and role rotation in a cardiac arrest simulation on learning immersion, learning confidence, and simulation satisfaction. Methods: This study was the descriptive survey and 199 nursing students completed a cardiac arrest simulation-based education program developed by the researcher. Participants repeated the simulation 3 times. Data were analyzed using time series, ANOVA, t-test with SPSS 21.0 program. Results: Over than 2 times was effective frequency of repetition of simulation. There were no differences in learning immersion, learning confidence and satisfaction after simulation due to rotation. Additionally, there were no differences in satisfaction after simulation. However, participants in the lead nursing role in simulation had less learning immersion and learning confidence compared to those not in the lead role. Conclusion: The results indicate that repeted use of the cardiac arrest simulation improved clinical practice; however, role rotation did not impact learning immersion or learning confidence. Even though there was no effect of role rotation, the results did indicate that experience as a leader in simulation is associated with less learning immersion and confidence. These results suggest the need to carefully debrief the lead nursing student. Further, in order to prevent nursing instructor burn-out and encourage participation of students in learning, future work should examine increased repetition frequency.
        4,000원
        6.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Colorectal cancer is a major cause of morbidity and mortality that accounts for over 9% of all incidences of cancer. Additionally, colorectal cancer is widely recognized as an environmental disease related to ill-defined cultural, social and lifestyle factors including physical activity, obesity, cigarette smoking and heavy alcohol consumption. Accordingly, natural phytochemicals and extracts have attracted attention because of their beneficial biological effects. Coenzyme Q10 (CoQ10) is a common supplementary medicine applied to increase bioenergetic capacity in various diseases. Therefore, in this study, we investigated whether CoQ10 treatment has any inhibitory effects and its related cellular mechanisms in human colon cancer HCT116 cells. A MTT assay revealed that CoQ10 slightly decreased the proliferation of HCT116 cells; however, glutathione- and superoxide dismutase- activity were unchanged in response to CoQ10 treatment. A DCF-DA assay revealed that CoQ10 slightly increased ROS release of HCT116 cells. However, in a nitric oxide (NO) assay, CoQ10 significantly increased NO production in a dose-dependent manner. The results of western blot analysis revealed that the protein levels of Bax, p21 and p53 were increased, whereas the protein level of Bcl2 was decreased suggesting that the CoQ10-mediated inhibitory mechanism is associated with apoptotic signaling. Taken together, our findings indicate that CoQ10 has an inhibitory effect on the growth of colon cancer cells via NO production that is associated with regulation of factors involved in apoptotic signaling including Bax, Bcl2, p21 and p53.
        4,000원
        8.
        2015.03 구독 인증기관 무료, 개인회원 유료
        Shikonin, a major ingredient in the traditional Chinese herb Lithospermumerythrorhizon, exhibits multiple biological functions including antimicrobial, anti-inflammatory, and antitumor effects. It has recently been reported that shikonin displays antitumor properties in many cancers. This study was aimed to investigate whether shikonin could inhibit oral squamous carcinoma cell (OSCC) growth via mechanisms of apoptosis and cell cycle arrest. The effects of shikonin on the viability and growth of OSCC cell line, SCC25 cells were assessed by MTT assay and clonogenic assays, respectively. Hoechst staining and DNA electrophoresis indicated that the shikonin-treated SCC25 cells were undergoing apoptosis. Western blotting, immunocytochemistry, confocal microscopy, flow cytometry, MMP activity, and proteasome activity also supported the finding that shikonin induces apoptosis. Shikonin treatment of SCC25 cells resulted in a time- and dose-dependent decrease in cell viability, inhibition of cell growth, and increase in apoptotic cell death. The treated SCC25 cells showed several lines of apoptotic manifestation as follows: nuclear condensation; DNA fragmentation; reduced MMP and proteasome activity; decrease in DNA contents; release of cytochrome c into cytosol; translocation of AIF and DFF40 (CAD) onto the nuclei; a significant shift in Bax/Bcl-2 ratio; and activation of caspase-9, -7, -6, and -3, as well as PARP, lamin A/C, and DFF45 (ICAD). Shikonin treatment also resulted in down-regulation of the G1 cell cycle-related proteins and up-regulation of p27KIP1. Taken together, our present findings demonstrate that shikonin strongly inhibits cell proliferation by modulating the expression of the G1 cell cycle-related proteins, and that it induces apoptosis via the proteasome, mitochondria, and caspase cascades in SCC25 cells.
        4,200원
        9.
        2014.03 구독 인증기관 무료, 개인회원 유료
        Several studies have shown that curcumin, which is derived from the rhizomes of turmeric, possesses antimicrobial, antioxidant and anti-inflammatory properties. The antitumor properties of curcumin have also now been demonstrated more recently in different cancers. This study was undertaken to investigate the modulation of cell cycle-related proteins and the mechanisms underlying apoptosis induction by curcumin in the SCC25 human tongue squamous cell carcinoma cell line. Curcumin treatment of the SCC25 cells resulted in a time- and dose-dependent reduction in cell viability and cell growth, and onset of apoptotic cell death. The curcumin-treated SCC25 cells showed several types of apoptotic manifestations, such as nuclear condensation, DNA fragmentation, reduced MMP and proteasome activity, and a decreased DNA content. In addition, the treated SCC25 cells showed a release of cytochrome c into the cytosol, translocation of AIF and DFF40/CAD into the nuclei, a significant shift in the Bax/Bcl-2 ratio, and the activation of caspase-9, caspase-7, caspase-6, caspase-3, PARP, lamin A/C, and DFF45/ICAD. Furthermore, curcumin exposure resulted in a downregulation of G1 cell cycle-related proteins and upregulation of p27KIP1. Taken together, our findings demonstrate that curcumin strongly inhibits cell proliferation by modulating the expression of G1 cell cycle-related proteins and inducing apoptosis via proteasomal, mitochondrial, and caspase cascades in SCC25 cells.
        4,200원
        10.
        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
        11.
        2011.03 구독 인증기관 무료, 개인회원 유료
        Heat shock protein 90 (Hsp90) is ATPase-directed molecular chaperon and affects survival of cancer cell. Inhibitory effect of Hsp90 by inducing cell cycle arrest and apoptosis in the cancer cell was reported. However, its role during oocyte maturation and early embryo development is very insufficient. In this study, we traced the effects of Hsp90 inhibitor, 17-allylamino-17-demethoxygeldanamycin (17-AAG), on meiotic maturation and early embryonic development in pigs. We also investigated several indicators of developmental potential, including structural integrity, gene expression (Hsp90-, cell cycle-, and apoptosis-related genes), and apoptosis, which are affected by 17-AAG. Then, we examined the roles of Hsp90 inhibitor on viability of primary cells in pigs. Porcine oocytes were cultured in the NCSU-23 medium with or without 17-AAG for 44 h. The proportion of GV arrested oocytes was significantly different between the 17-AAG treated and untreated group (78.2 vs 34.8%, p<0.05). After completion of meiotic maturation, the proportion of MII oocytes was lower in the 17-AAG treated group than in the control group (27.9 vs 71.0%, p<0.05). After IVF, the percentage of penetrated oocytes was significantly lower in the 17-AAG treated group (25.2%), resulting in lower normal pronucleus formation (2PN of 14.6%). Therefore, the inhibition of meiotic progression by Hsp90 inhibitor played a critical role in fertilization status. Porcine embryo were cultured in the PZM-3 medium with or without 17-AAG for 6 days. In result, significant differences in developmental potential were detected between the embryos that were cultured with or without 17-AAG. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) showed that the number of containing fragmented DNA at the blastocyst stage increased in the 17-AAG treated group compared with control (7.5 vs 4.4, respectively). Blastocysts that developed in the 17-AAG treated group had low structural integrity and high apoptotic nuclei than those of the untreated control, resulting in decrease the embryonic qualities of preimplantation porcine blastocysts. The mRNA expressions of cell cycle-related genes were down-regulated in the 17-AAG treated group compared with control. Also, the expression of the pro-apoptotic gene Bax increased in 17-AAG treated group, whereas expression of the anti-apoptotic gene Bcl-XL decreased. However, the expression of ER stress-related genes did not changed by 17-AAG. Cultured pESF cells were treated with or without 17-AAG and used for MTT assay. The results showed that viability of pESF cells were decreased by treatment of 17-AAG (2 μM) for 24 hr. These results indicated that 17-AAG decreased cell proliferation and increased cell death. Expression patterns Hsp90 complex genes (Hsp70 and p23), cell cycle-related genes (cdc2 and cdc25c) and apoptosis-related genes (Bax and Bcl-XL) were significantly changed by using RT-PCR analysis. The spliced form of pXbp-1 product (pXbp-1s) was detected in the tunicamycin (TM) treated cells, but it is not detected in 17-AAG treated cells. In conclusion, Hsp90 appears to play a direct role in porcine early embryo developmental competence including structural integrity of blastocysts. Also, these results indicate that Hsp90 is closely associated with cell cycle- and apoptosis-related genes expression in developing porcine embryos.
        4,500원
        12.
        2011.03 구독 인증기관 무료, 개인회원 유료
        Chios gum mastic (CGM) is produced from Pistiacia lentiscus L var chia, which grows only on Chios Island in Greece. CGM is a kind of resin extracted from the stem and leaves, has been used for many centuries in many Mediterranean countries as a dietary supplement and folk medicine for stomach and duodenal ulcers. CGM is known to induce cell cycle arrest and apoptosis in some cancer cells. This study was undertaken to investigate the alteration of the cell cycle and induction of apoptosis following CGM treatment of HL-60 cells. The viability of the HL-60 cells was assessed using the MTT assay. Hoechst staining and DNA electrophoresis were employed to detect HL-60 cells undergoing apoptosis. Western blotting, immunocytochemistry, confocal microscopy, FACScan flow cytometry, MMP activity and proteasome activity analyses were also employed. CGM treatment of HL-60 cells was found to result in a dose- and time-dependent decrease in cell viability and apoptotic cell death. Tested HL-60 cells showed a variety of apoptotic manifestations and induced the downregulation of G1 cell cycle-related proteins. Taken collectively, our present findings demonstrate that CGM strongly induces G1 cell cycle arrest via the modulation of cell cycle-related proteins, and also apoptosis via proteasome, mitochondrial and caspase cascades in HL-60 cells. Hence, we provide evidence that a natural product, CGM could be considered as a novel therapeutic for human leukemia.
        4,000원
        13.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The trace element nutrient selenium discharges its well-known nutritional anti-tumor activity. Converging data from epidemiological, ecological and clinical studies have shown that selenium can decrease the risk for some types of human cancers, especially those of the prostate, lung, and colon. Mechanistic studies have indicated that selenium has many desirable attributes of chemoprevention targeting cancer cells through DNA single strand breaks, the induction of reactive oxygen species. However, there is no reports about the relationship between methylseleninic acid (MSeA), one of methylselenol metabolites and cell cycle arrest in LNCaP human prostate cancer cells. Our data showed that MSeA arrested G1/S pahse of cell cycle arrest and inhibited DNA synthesis in LNCaP cells and those cellular events by MSeA were due to the induction of p27 protein which is a well-known cyclin-dependent kinase inhibitor. Taken together, cell cycle arrest occurred by MSeA may contribute to the growth-inhibition of prostate cancer cells.
        4,000원
        14.
        2009.06 구독 인증기관 무료, 개인회원 유료
        The Maillard Reaction Products (MRPs) such as Glucose-tyrosine (Glu-Tyr) and Xylose-arginine (Xyl-Arg) have antioxidant, antimutagenic, and antibacterial effects. However, to date, still little is known about the other biological effects of the MRPs. In this study, we investigated whether the fructose-tyrosine MRP, 2,4-bis(p-hydroxyphenyl)-2-butenal (Fru-Tyr), could modulate cell cycle progression and NF-κB activity, and thereby induce apoptotic cell death of colon cancer cells. Treatment with different concentrations (10-40 μg/ ml) of Fru-Tyr for 24 h inhibited colon cancer cell (SW620 and HCT116) growth followed by induction of G2/M phase cell cycle arrest and apoptosis in a dose-dependent manner. We also found that Fru-Tyr suppressed tumor necrosis factor-alpha (TNF-α)-induced NF-κB transcriptional activity. Moreover, Fru-Tyr induced the expression of apoptotic gene, cleaved caspse-3. These results suggest that Fru-Tyr inhibited colon cancer cell growth through induction of G2/M phase cell cycle arrest and apoptotic cell death by modulating of NF-κB.
        4,000원
        16.
        2007.06 구독 인증기관 무료, 개인회원 유료
        Previous studies have shown that BMI-1026 is a potent inhibitor of the cyclin-dependent kinases (cdk). In cell culture, the compound also arrests G2/M strongly and G1/S and S weakly. Two key kinases, cdk1 (p34cdc2 kinase) and mitogen-activated protein (MAP) kinase (erk1 and 2), perform crucial roles during oocyte maturation and, later, metaphase II (MII) arrest. In mammalian oocytes, both kinases are activated gradually around the time of germinal vesicle breakdown (GVBD) and maintain high activity in eggs arrested at metaphase II. In this study, we examined the effects of BMI-1026 on GVBD and MII arrest in mouse oocytes. BMI-1026 inhibited GVBD of immature oocytes and activated MII-arrested oocytes in a concentration-dependent manner, with more than 90% of oocytes exhibiting GVBD inhibition and MII activation at 100 nM. This is approximately 500~1,000 times more potent than the activity reported for the cdk inhibitors roscovitine (~50 M) and butyrolactone (~100 M). Based on the results of previous in vitro kinase assays, we expected BMI-1026 to inhibit only cdk1 activation in oocytes and eggs, not MAP kinase. However, in our cell-based system, it inhibited the activity of both kinases. We also found that the effect of BMI-1026 is reversible. Our results suggest that BMI-1026 inhibits GVBD and activates MII-arrested oocytes efficiently and reversibly and that it also inhibits both cdk1/histone H1 kinase and MAP kinase in mouse oocytes.
        4,000원
        18.
        2005.10 KCI 등재 구독 인증기관·개인회원 무료
        뻐ny studìes have shown the anti-proli ferative effects of irondeprivation on cancer cell s‘ but the effects 01' iron-chelators on oral cancer have not been clearly elucidated , To investigate the effects of an iron chelato r, desferrioxamine( 01"O).on the growth of ilIllTIortali zed human o1'al ke ratinocytes(IHOK), primary oraJ cancer cel ls(HN4)‘ metastatic oral cancer cell s(HN12) , and human skin keratìnocytes(HaCaT) in the MTr assay, three-dimensional(3D) raft cul tmes, Western blott ing, cell cycJ e analysis‘ nuclear staining‘ and cytochrome c expression for apoptosis s ig naling pathway were used OFO inhibited the growth of immortalized IHOK and HaCaT and mal ignant HN4 and HN12 keratinocytes in a time- and dose-dependent manner according to the MTT assay, The 3D organotypic cu l tu re also revealed that OF'O-treated cells showed less epithelial maturation, less surface keratinizati on‘ and de creased epithelia l thickness, The major mechanìsm of growth inhìbition with the micromolar 0 1"0 treatment was by the induction of apoptosis‘ which was supported by nuclear OAPI staining, ONA fragmentation analysis, and J10w cytometric analysis for sub-Gl phase ar rest and Annexin V-1"ITC stainìng, Furthermore‘ Bax expression in creased together with p53 and p21WAF1!CIPl, whìle the Bcl-2 expression decreased in the immortalized and malig nant keratinocytes treated with 01"0 , Time-dependent cytochrome c from mitochondria was observed in D1"O-treated [l-IOK and 0 1'머 cancel‘ ceJJ s, and was accompanied by the activation of caspase-3 in IHOK cells. These resu lts demonstrate that 0 1"0 has growth inhibitory effects on immortalized and malignant oral keratinocyLes Lhrough the induction of apoptosis and suggest that further evaluation of OFO as a potcntial thcrapcutic agent for human oral precancerous and cancerous lesions is warranted
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