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Search Results: 1 - 10 of 17920 matches for " Kyung-Hee Chun "
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Effect of L-Deprenyl on the Putrescine Level and Neuronal Damage after Transient Global Cerebral Ischemia in Gerbils  [PDF]
Hyung Lee, Yeun-Kyung Chu, Joon-Ho Shon, Kyung-Hee Chun, Jee-In Kim, Seong-Ryong Lee
International Journal of Organic Chemistry (IJOC) , 2017, DOI: 10.4236/ijoc.2017.72014
Abstract: L-Deprenyl is selective and irreversible monoamine oxidase B inhibitor, known to have neuroprotective properties. Putrescine, one of polyamine, is thought to be important in the neuronal cell damage associated with various type of excitatory neurotoxicity. We examined the effects of L-deprenyl on the changes in putrescine level and neuronal damage after transient global ischemia in ger-bils. Male Mongolian gerbils weighing 65 - 75 g were used in the experiment. Global ischemia was induced by occlusion of common carotid arteries for 3 min to observe neuronal injury in hippocampal pyramidal cells. L-Deprenyl group was given 10 mg/kg of L-deprenyl intraperitoneally immediately after, 3 h and 6 h after global ischemia. Treated animals were processed in parallel with ischemic animals receiving saline as a vehicle and with sham- operated controls. Hippocampal putrescine level was increased by global ischemia and inhibited by L-deprenyl treatment. In histological findings, counts of viable neurons were made in the pyramidal cell layer of the hippocampal CA1 area 3 days after ischemic insult. The number of viable neurons in the pyramidal cell layer of CA1 area was significantly increased in animals treated with L-deprenyl compared to vehicle-treated ischemic animals (p < 0.05). In terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick endlabeling (TUNEL) assay, semiquantitative analysis of dark-brown neuronal cells was made in the hippocampal CA1 area. There was also a significant difference in the degree of TUNEL staining in the hippocampal CA1 area between vehi-cle-treated and L-deprenyl-treated animals (p < 0.05). These data show L-deprenyl is effective as a prophylactic treatment for neuronal injury when it is administrated before ischemia but a further study need to know the effects of administration of L-deprenyl after ischemia and at given times after reper-fusion.
Galectin-3 Facilitates Cell Motility in Gastric Cancer by Up-Regulating Protease-Activated Receptor-1(PAR-1) and Matrix Metalloproteinase-1(MMP-1)
Seok-Jun Kim, Ji-Young Shin, Kang-Duck Lee, Young-Ki Bae, Il-Ju Choi, Seok Hee Park, Kyung-Hee Chun
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0025103
Abstract: Background Galectin-3 is known to regulate cancer metastasis. However, the underlying mechanism has not been defined. Through the DNA microarray studies after galectin-3 silencing, we demonstrated here that galectin-3 plays a key role in up-regulating the expressions of protease-activated receptor-1(PAR-1) and matrix metalloproteinase-1(MMP-1) PAR-1 thereby promoting gastric cancer metastasis. Methodology/Principal Findings We examined the expression levels of Galectin-3, PAR-1, and MMP-1 in gastric cancer patient tissues and also the effects of silencing these proteins with specific siRNAs and of over-expressing them using specific lenti-viral constructs. We also employed zebrafish embryo model for analysis of in vivo gastric cancer cell invasion. These studies demonstrated that: a) galectin-3 silencing decreases the expression of PAR-1. b) galectin-3 over-expression increases cell migration and invasion and this increase can be reversed by PAR-1 silencing, indicating that galectin-3 increases cell migration and invasion via PAR-1 up-regulation. c) galectin-3 directly interacts with AP-1 transcriptional factor, and this complex binds to PAR-1 promoter and drives PAR-1 transcription. d) galectin-3 also amplifies phospho-paxillin, a PAR-1 downstream target, by increasing MMP-1 expression. MMP-1 silencing blocks phospho-paxillin amplification and cell invasion caused by galectin-3 over-expression. e) Silencing of either galectin-3, PAR-1 or MMP-1 significantly reduced cell migration into the vessels in zebrafish embryo model. f) Galectin-3, PAR-1, and MMP-1 are highly expressed and co-localized in malignant tissues from gastric cancer patients. Conclusions/Significance Galectin-3 plays the key role of activating cell surface receptor through production of protease and boosts gastric cancer metastasis. Galectin-3 has the potential to serve as a useful pharmacological target for prevention of gastric cancer metastasis.
MicroRNA let-7a suppresses breast cancer cell migration and invasion through downregulation of C-C chemokine receptor type 7
Seok-Jun Kim, Ji-Young Shin, Kang-Duck Lee, Young-Ki Bae, Ki Sung, Seok Nam, Kyung-Hee Chun
Breast Cancer Research , 2012, DOI: 10.1186/bcr3098
Abstract: The expression of CCR7, its ligand CCL21, and let-7a was detected in breast cancer cell lines and in breast cancer patient tissues. Synthetic let-7a and an inhibitor of let-7a were transfected into MDA-MB-231 and MCF-7 breast cancer cells, respectively, and cell proliferation, cell migration, and invasion assays were performed. To confirm the fact that 3'UTR of CCR7 is a direct target of let-7a, a luciferase assay for the reporter gene expressing the let-7a binding sites of CCR7 3'UTR was used. An in vivo invasion animal model system using transparent zebrafish embryos was also established to determine the let-7a effect on breast cancer cell invasion.First, a higher expression of both CCR7 and CCL21 in malignant tissues than in their normal counterparts from breast cancer patients was observed. In addition, a reverse correlation in the expression of CCR7 and let-7a in breast cancer cell lines and breast cancer patient tissues was detected. Synthetic let-7a decreased breast cancer cell proliferation, migration, and invasion, as well as CCR7 protein expression in MDA-MB-231 cells. The let-7a inhibitor reversed the let-7a effects on the MCF-7 cells. The 3'UTR of CCR7 was confirmed as a direct target of let-7a by using the luciferase assay for the reporter gene expressing let-7a CCR7 3'UTR binding sites. Notably, when analyzing in vivo invasion, MDA-MB 231 cells after synthetic let-7a transfection were unable to invade the vessels in zebrafish embryos.The results from the present study suggest that targeting of CCL21-CCR7 signaling is a valid approach for breast cancer therapy and that let-7a directly binds to the 3'UTR of CCR7 and blocks its protein expression, thereby suppressing migration and invasion of human breast cancer cells. Furthermore, the present study underscores the therapeutic potential of let-7a as an antitumor and antimetastatic manager in breast cancer patients.Breast cancer is the most common cancer in women and is ranked second only to lung cancer in
Plant RNA binding proteins for control of RNA virus infection
Sung Un Huh,Kyung-Hee Paek
Frontiers in Physiology , 2013, DOI: 10.3389/fphys.2013.00397
Abstract: Plant RNA viruses have effective strategies to infect host plants through either direct or indirect interactions with various host proteins, thus suppressing the host immune system. When plant RNA viruses enter host cells exposed RNAs of viruses are recognized by the host immune system through processes such as siRNA-dependent silencing. Interestingly, some host RNA binding proteins have been involved in the inhibition of RNA virus replication, movement, and translation through RNA-specific binding. Host plants intensively use RNA binding proteins for defense against viral infections in nature. In this mini review, we will summarize the function of some host RNA binding proteins which act in a sequence-specific binding manner to the infecting virus RNA. It is important to understand how plants effectively suppress RNA virus infections via RNA binding proteins, and this defense system can be potentially developed as a synthetic virus defense strategy for use in crop engineering.
His or Her Parents? Perceived Parental Approval of Romantic Relationships Among College Students and Their Partners
Kyung-Hee Lee,Andrea V. R. Swenson,Sylvia Niehuis
Interpersona : An International Journal on Personal Relationships , 2010,
Abstract: Using social capital theory, this study of 194 dating couples examined the connection between parents’ approval of the dating relationship (reported by each couple member for his/her own parents and the partner’s parents) and participants’ relationship distress. The Actor-Partner-Interdependence Model within Structural Equation Modeling served as the data-analytic tool. Results showed that, in support of the theory, relationship approval from strong ties (one’s own parents) and from weak ties (one’s partner’s parents) manifested themselves differently in romantic relationships. Specifically, both men’s and women’s perception of relationship approval from their own parents (strong ties) and from their partner’s parents (weak ties) negatively predicted couple members’ own relationship distress. Moreover, path coefficients between men’s and women’s strong ties and their own relationship distress were roughly twice as large as those between men’s and women’s weak ties and their relationship distress. Findings were less clear for the association between perceptions of relationship approval from one’s own and one’s partner’s parents and the dating partners’ relationship distress. The findings are discussed in light of prior research and theory on social capital.
Charting a Moral Life: The Influence of Stigma and Filial Duties on Marital Decisions among Chinese Men who Have Sex with Men
Wayne T. Steward, Pierre Miège, Kyung-Hee Choi
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0071778
Abstract: Introduction Stigma constitutes a critical challenge to the rising rates of HIV among Chinese men who have sex with men (MSM). It reduces willingness to disclose one’s sexual orientation and can lead to concurrent sexual partnerships. Disclosure decisions are also affected by cultural norms that place pressures on sons to marry. In this manuscript, we characterize how stigma and cultural factors influenced Chinese MSM’s decisions around disclosure and marriage. We seek to show that MSM’s actions were motivated by moral considerations, even when those choices posed HIV transmission risks. Methods We conducted qualitative interviews with 30 MSM in Beijing, China. Interviews were audio-recorded, transcribed, and translated into English for analysis. Transcripts were coded using a procedure that allowed for themes to emerge organically. Results Participants struggled with feelings of shame and believed that others possessed stigmatizing attitudes about homosexuality. They had experienced relatively little discrimination because they infrequently disclosed their MSM status. In response to marital pressures, participant had to reconcile same-sex attractions with filial expectations. Their choices included: not being involved with women; putting on the appearance of a heterosexual relationship by marrying a lesbian; or fulfilling family expectations by marrying a heterosexual woman. Regardless of the decision, many rooted the justifications for their choices in the considerations they had given to others’ needs. Conclusion The growing epidemic among MSM in China requires action from the public health community. As programs are scaled up to serve these men, it is critical to remember that MSM, who often fear social sanction if they were to reveal their sexual orientation, continue to face the same pressures from culturally normative social duties as heterosexual men. Interventions must find ways to help men navigate a balance between their own needs and the responsibilities they feel toward their parents and others.
Understanding of Ultrasonic Assisted Machining with Diamond Grinding Tool  [PDF]
Kyung-Hee Park, Yun-Hyuck Hong, Kyeong-Tae Kim, Seok-Woo Lee, Hon-Zong Choi, Young-Jae Choi
Modern Mechanical Engineering (MME) , 2014, DOI: 10.4236/mme.2014.41001

In this work, machining test was carried out in various machining conditions using ultrasonic vibration capable CNC machine. For work material, alumina ceramic (Al2O3) was used while for tool material diamond electroplated grinding wheel was used. To evaluate ultrasonic vibration effect, grinding test was performed with and without ultrasonic vibration in same machining condition. In ultrasonic mode, ultrasonic vibration of 20 kHz was generated by HSK 63 ultrasonic actuator. On the other hand, grinding forces were measured by KISTLER dynamometer. And an optimal sampling rate for grinding force measurement was obtained by a signal processing and frequency analysis. The surface roughness of the ceramic was also measured by using stylus type surface roughness instrument and atomic force microscope (AFM). Besides, the scanning electron microscope (SEM) was used for observation of surface integrality.

Myocardial scarring on cardiovascular magnetic resonance in asymptomatic or minimally symptomatic patients with “pure” apical hypertrophic cardiomyopathy
Kim Kyung-Hee,Kim Hyung-Kwan,Hwang In-Chang,Lee Seung-Pyo
Journal of Cardiovascular Magnetic Resonance , 2012, DOI: 10.1186/1532-429x-14-52
Abstract: Background Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) enables state-of-the-art in vivo evaluations of myocardial fibrosis. Although LGE patterns have been well described in asymmetrical septal hypertrophy, conflicting results have been reported regarding the characteristics of LGE in apical hypertrophic cardiomyopathy (ApHCM). This study was undertaken to determine 1) the frequency and distribution of LGE and 2) its prognostic implication in ApHCM. Methods Forty patients with asymptomatic or minimally symptomatic pure ApHCM (age, 60.2 ± 10.4 years, 31 men) were prospectively enrolled. LGE images were acquired using the inversion recovery segmented spoiled-gradient echo and phase-sensitive inversion recovery sequence, and analyzed using a 17-segment model. Summing the planimetered LGE areas in all short axis slices yielded the total volume of late enhancement, which was subsequently presented as a proportion of total LV myocardium (% LGE). Results Mean maximal apical wall thickness was 17.9±2.3mm, and mean left ventricular (LV) ejection fraction was 67.7 ± 8.0%. All but one patient presented with electrocardiographic negative T wave inversion in anterolateral leads, with a mean maximum negative T wave of 7.2 ± 4.7mm. Nine patients (22.5%) had giant negative T waves, defined as the amplitude of ≥10mm, in electrocardiogram. LGE was detected in 130 segments of 30 patients (75.0%), occupying 4.9 ± 5.5% of LV myocardium. LGE was mainly detected at the junction between left and right ventricles in 12 (30%) and at the apex in 28 (70%), although LGE-positive areas were widely distributed, and not limited to the apex. Focal LGE at the non-hypertrophic LV segments was found in some ApHCM patients, even without LGE of hypertrophied apical segments. Over the 2-year follow-up, there was no one achieving the study end-point, defined as all-cause death, sudden cardiac death and hospitalization for heart failure. Conclusions LGE was frequently observed not only in the thickened apex of the heart but also in other LV segments, irrespective of the presence or absence of hypertrophy. The simple presence of LGE on CMR was not representative of adverse prognosis in this population.
Up-regulated expression of l-caldesmon associated with malignancy of colorectal cancer
Kim Kyung-Hee,Yeo Seung-Gu,Kim Won Ki,Kim Dae Yong
BMC Cancer , 2012, DOI: 10.1186/1471-2407-12-601
Abstract: Background Caldesmon (CaD), a major actin-associated protein, is found in smooth muscle and non-muscle cells. Smooth muscle caldesmon, h-CaD, is a multifunctional protein, and non-muscle cell caldesmon, l-CaD, plays a role in cytoskeletal architecture and dynamics. h-CaD is thought to be an useful marker for smooth muscle tumors, but the role(s) of l-CaD has not been examined in tumors. Methods Primary colon cancer and liver metastasis tissues were obtained from colon cancer patients. Prior to chemoradiotherapy (CRT), normal and cancerous tissues were obtained from rectal cancer patients. Whole-tissue protein extracts were analyzed by 2-DE-based proteomics. Expression and phosphorylation level of main cellular signaling proteins were determined by western blot analysis. Cell proliferation after CaD siRNA transfection was monitored by MTT assay. Results The expression level of l-CaD was significantly increased in primary colon cancer and liver metastasis tissues compared to the level in the corresponding normal tissues. In cancerous tissues obtained from the patients showing poor response to CRT (Dworak grade 4), the expression of l-CaD was increased compared to that of good response group (Dworak grade 1). In line with, l-CaD positive human colon cancer cell lines were more resistant to 5-fluorouracil (5-FU) and radiation treatment compared to l-CaD negative cell lines. Artificial suppression of l-CaD increased susceptibility of colon cancer cells to 5-FU, and caused an increase of p21 and c-PARP, and a decrease of NF-kB and p-mTOR expression. Conclusion Up-regulated expression of l-CaD may have a role for increasing metastatic property and decreasing CRT susceptibility in colorectal cancer cells.
朴春根,Kim Kyung-hee,Lee Sang-hyun,Lee Seung-kyu
植物保护学报 , 2007,
Abstract: 为了分析韩国栗疫病的抗病品种和感病品种的遗传变异和抗病性的筛选,利用抗病性的快速检测法和RAPD(randomamplifiedpolymorphicDNA)方法对13个栗树品种进行了抗病性检测和RAPD标记分析。抗病性的快速检测选出了5个抗病品种、5个感病品种和3个中度抗病(或中度感病)品种,并且这一结果与该品种的田间表现相一致。利用筛选的12个随机引物,扩增了100个多态性RAPD片段,但未发现与抗病性或感病性相关的特异RAPD片段。聚类分析结果表明,12个品种大致分为抗病、感病和中度抗病(或中度感病)等3个大组,并与抗病性的快速检测结果基本一致。抗病品种"MANSEKI"表现出了相对于12个品种较远的亲缘关系。
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