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Search Results: 1 - 10 of 23035 matches for " Ji Hae Park "
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Cobalt chloride stimulates phosphoinositide 3-kinase/Akt signaling through the epidermal growth factor receptor in oral squamous cell carcinoma
Heon Ryu,Mi; Hee Park,Jeong; Eun Park,Ji; Chung,Jin; Hun Lee,Chang; Ryoun Park,Hae;
Biocell , 2010,
Abstract: tumor cells are often found under hypoxic conditions due to the rapid outgrowth of their vascular supply, and, in order to survive hypoxia, these cells induce numerous signaling factors. akt is an important kinase in cell survival, and its activity is regulated by the upstream phosphoinositide 3-kinase (pi3k) and receptor tyrosine kinases (rtks). in this study, we examined akt activation and rtks/pi3k/akt signaling using the hypoxia-mimetic cobalt chloride in oral squamous carcinoma cells. cobalt chloride increases akt phosphorylation in both a dose- and time-dependent manner. blocking the activation of the pi3k/akt pathway using ly294002 abolished akt activation in response to cobalt chloride, suggesting that akt phosphorylation by cobalt chloride is dependent on pi3k. in addition, activation of the pi3k/akt pathway seems to rely on the epidermal growth factor receptor (egfr), since the inhibition of egfr attenuated cobalt chloride-induced akt activation. the results in this study also demonstrate that cobalt chloride increases egfr protein levels and induces oral squamous cell carcinoma cells to enter s phase.
Potent Anti-Diabetic Effects of MHY908, a Newly Synthesized PPAR α/γ Dual Agonist in db/db Mice
Min Hi Park, Ji Young Park, Hye Jin Lee, Dae Hyun Kim, Daeui Park, Hyoung Oh Jeong, Chan Hum Park, Pusoon Chun, Hyung Ryong Moon, Hae Young Chung
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0078815
Abstract: Peroxisome proliferator-activated receptor (PPAR) α/γ dual agonists have been developed to alleviate metabolic disorders and have the potential to be used as therapeutic agents for the treatment of type 2 diabetes. In this study, we investigated the effects of a newly synthesized PPAR α/γ dual agonist, 2-[4-(5-chlorobenzo [d] thiazol-2-yl) phenoxy]-2-methylpropanoic acid (MHY908) on type 2 diabetes in vitro and in vivo. To obtain initial evidence that MHY908 acts as a PPAR α/γ dual agonist, ChIP and reporter gene assays were conducted in AC2F rat liver cells, and to investigate the anti-diabetic effects and molecular mechanisms, eight-week-old, male db/db mice were allowed to eat ad libitum, placed on calorie restriction, or administered MHY908 (1 mg or 3 mg/kg/day) mixed in food for 4 weeks. Age-matched male db/m lean mice served as non-diabetic controls. It was found that MHY908 enhanced the binding and transcriptional activity of PPAR α and γ in AC2F cells, and it reduced serum glucose, triglyceride, and insulin levels, however increased adiponectin levels without body weight gain. In addition, MHY908 significantly improved hepatic steatosis by enhancing CPT-1 levels. Remarkably, MHY908 reduced endoplasmic reticulum (ER) stress and c-Jun N-terminal kinase (JNK) activation in the livers of db/db mice, and subsequently reduced insulin resistance. The study shows MHY908 has beneficial effects on type 2 diabetes by simultaneously activating PPAR α/γ and improving ER stress, and suggests that MHY908 could have a potent anti-diabetic effect as a PPAR α/γ dual agonist, and potential for the treatment of type 2 diabetes.
Molecular Study of Dietary Heptadecane for the Anti-Inflammatory Modulation of NF-kB in the Aged Kidney
Dae Hyun Kim, Min Hi Park, Yeon Ja Choi, Ki Wung Chung, Chan Hum Park, Eun Ji Jang, Hye Jin An, Byung Pal Yu, Hae Young Chung
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0059316
Abstract: Heptadecane is a volatile component of Spirulina platensis, and blocks the de novo synthesis of fatty acids and ameliorates several oxidative stress-related diseases. In a redox state disrupted by oxidative stress, pro-inflammatory genes are upregulated by the activation of NF-kB via diverse kinases. Thus, the search and characterization of new substances that modulate NF-kB are lively research topics. In the present study, heptadecane was examined in terms of its ability to suppress inflammatory NF-kB activation via redox-related NIK/IKK and MAPKs pathway in aged rats. In the first part of the study, Fischer 344 rats, aged 9 and 20 months, were administered on average approximately 20 or 40 mg/Kg body weight over 10 days. The potency of heptadecane was investigated by examining its ability to suppress the gene expressions of COX-2 and iNOS (both NF-κB-related genes) and reactive species (RS) production in aged kidney tissue. In the second part of the study, YPEN-1 cells (an endothelial cell line) were used to explore the molecular mechanism underlying the anti-inflammatory effect of heptadecane by examining its modulation of NF-kB and NF-kB signal pathway. Results showed that heptadecane exhibited a potent anti-oxidative effect by protecting YPEN-1 cells from tert-butylhydroperoxide induced oxidative stress. Further molecular investigations revealed that heptadecane attenuated RS-induced NF-kB via the NIK/IKK and MAPKs pathways in YPEN-1 cells and aged kidney tissues. Based on these results, we conclude that heptadecane suppresses age-related increases in pro-inflammatory gene expressions by reducing NF-kB activity by upregulating the NIK/IKK and MAPKs pathways induced by RS. These findings provide molecular insight of the mechanisms by which heptadecane exerts its antiinflammatory effect in aged kidney tissues. We conclude that heptadecane suppresses age-related increases in pro-inflammatory gene expressions then travel upstream set by step by reducing NF-kB activity by downregulating the NIK/IKK and MAPKs pathways induced by RS.
The Novel PPAR α/γ Dual Agonist MHY 966 Modulates UVB–Induced Skin Inflammation by Inhibiting NF-κB Activity
Min Hi Park, Ji Young Park, Hye Jin Lee, Dae Hyun Kim, Ki Wung Chung, Daeui Park, Hyoung Oh Jeong, Hye Rim Kim, Chan Hum Park, So Ra Kim, Pusoon Chun, Youngjoo Byun, Hyung Ryong Moon, Hae Young Chung
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0076820
Abstract: Ultraviolet B (UVB; 290~320nm) irradiation-induced lipid peroxidation induces inflammatory responses that lead to skin wrinkle formation and epidermal thickening. Peroxisome proliferator-activated receptor (PPAR) α/γ dual agonists have the potential to be used as anti-wrinkle agents because they inhibit inflammatory response and lipid peroxidation. In this study, we evaluated the function of 2-bromo-4-(5-chloro-benzo[d]thiazol-2-yl?)phenol (MHY 966), a novel synthetic PPAR α/γ dual agonist, and investigated its anti-inflammatory and anti-lipid peroxidation effects. The action of MHY 966 as a PPAR α/γ dual agonist was also determined in vitro by reporter gene assay. Additionally, 8-week-old melanin-possessing hairless mice 2 (HRM2) were exposed to 150 mJ/cm2 UVB every other day for 17 days and MHY 966 was simultaneously pre-treated every day for 17 days to investigate the molecular mechanisms involved. MHY 966 was found to stimulate the transcriptional activities of both PPAR α and γ. In HRM2 mice, we found that the skins of mice exposed to UVB showed significantly increased pro-inflammatory mediator levels (NF-κB, iNOS, and COX-2) and increased lipid peroxidation, whereas MHY 966 co-treatment down-regulated these effects of UVB by activating PPAR α and γ. Thus, the present study shows that MHY 966 exhibits beneficial effects on inflammatory responses and lipid peroxidation by simultaneously activating PPAR α and γ. The major finding of this study is that MHY 966 demonstrates potential as an agent against wrinkle formation associated with chronic UVB exposure.
Inhibitory Effect of mTOR Activator MHY1485 on Autophagy: Suppression of Lysosomal Fusion
Yeon Ja Choi, Yun Jung Park, Ji Young Park, Hyoung Oh Jeong, Dae Hyun Kim, Young Mi Ha, Ji Min Kim, Yu Min Song, Hyoung-Sam Heo, Byung Pal Yu, Pusoon Chun, Hyung Ryong Moon, Hae Young Chung
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0043418
Abstract: Autophagy is a major degradative process responsible for the disposal of cytoplasmic proteins and dysfunctional organelles via the lysosomal pathway. During the autophagic process, cells form double-membraned vesicles called autophagosomes that sequester disposable materials in the cytoplasm and finally fuse with lysosomes. In the present study, we investigated the inhibition of autophagy by a synthesized compound, MHY1485, in a culture system by using Ac2F rat hepatocytes. Autophagic flux was measured to evaluate the autophagic activity. Autophagosomes were visualized in Ac2F cells transfected with AdGFP-LC3 by live-cell confocal microscopy. In addition, activity of mTOR, a major regulatory protein of autophagy, was assessed by western blot and docking simulation using AutoDock 4.2. In the result, treatment with MHY1485 suppressed the basal autophagic flux, and this inhibitory effect was clearly confirmed in cells under starvation, a strong physiological inducer of autophagy. The levels of p62 and beclin-1 did not show significant change after treatment with MHY1485. Decreased co-localization of autophagosomes and lysosomes in confocal microscopic images revealed the inhibitory effect of MHY1485 on lysosomal fusion during starvation-induced autophagy. These effects of MHY1485 led to the accumulation of LC3II and enlargement of the autophagosomes in a dose- and time- dependent manner. Furthermore, MHY1485 induced mTOR activation and correspondingly showed a higher docking score than PP242, a well-known ATP-competitive mTOR inhibitor, in docking simulation. In conclusion, MHY1485 has an inhibitory effect on the autophagic process by inhibition of fusion between autophagosomes and lysosomes leading to the accumulation of LC3II protein and enlarged autophagosomes. MHY1485 also induces mTOR activity, providing a possibility for another regulatory mechanism of autophagy by the MHY compound. The significance of this study is the finding of a novel inhibitor of autophagy with an mTOR activating effect.
A single nucleotide polymorphism in CAPN1 associated with marbling score in Korean cattle
Hyun Cheong, Du-Hak Yoon, Byung Park, Lyoung Kim, Joon Bae, Sohg Namgoong, Hae Lee, Chang Han, Ji Kim, Il-Cheong Cheong, Hyoung Shin
BMC Genetics , 2008, DOI: 10.1186/1471-2156-9-33
Abstract: By direct DNA sequencing in 24 unrelated Korean cattle, we identified 39 sequence variants within exons and their flanking regions in CAPN1. Among them, 12 common polymorphic sites were selected for genotyping in the beef cattle (n = 421). Statistical analysis revealed that a polymorphism in the 3'UTR (c.2151*479C>T) showed significant association with MS (Pcor. = 0.02).Our findings suggest that polymorphisms in CAPN1 might be one of the important genetic factors involved in carcass quality in beef cattle, although it could be false positive association.Genetic improvement has long been considered an important factor in the competitiveness of beef cattle production. Identification of the genes and/or polymorphisms underlying quantitative/qualitative traits, and an understanding of how these genes/polymorphisms interact with the environment or with other genes affecting economic traits might be the keys to successful application of marker-assisted selection in the commercial animal population. As one of these economic traits, marbling is intramuscular fat that gives meat flavor and tenderness. Thus, an increase in the degree of marbling raises the level of meat quality.Calpain is a ubiquitous cytoplasmic cysteine protease, the activity of which is absolutely dependent on calcium [1]. Two genes of calpain (CAPN1 [macro-calpain] and CAPN2 [mili-calpain]) have been identified [2]. CAPN1 degrades myofibrillar proteins under postmortem conditions and appears to be the primary enzyme in the postmortem tenderization process [3-6]. Regulation of CAPN1 activity has been correlated with variation in meat tenderness, and previous studies also identified a quantitative trait locus influencing meat tenderness on chromosome 29 where CAPN1 lies [7-9].In the CAPN1 gene, more than 100 single nucleotide polymorphisms (SNPs) have been identified in Bos indicus or Bos taurus [8,10,11] (S. N. White and T. Smith, unpublished data). Among them, four polymorphisms, two non-synonymous SNPs (
Preparation of Thiophene-Fused and Tetrahydroquinoline-Linked Cyclopentadienyl Titanium Complexes for Ethylene/α-Olefin Copolymerization
Sung Hun Kim,Ji Hae Park,Bo Geun Song,Seung-Woong Yoon,Min Jeong Go,Junseong Lee,Bun Yeoul Lee
Catalysts , 2013, DOI: 10.3390/catal3010104
Abstract: A synthetic scheme was developed for the large-scale preparation of a dimethylthiophene-fused and tetrahydroquinaldine-linked dimethylcyclopentadienyl titanium complex ( 2), which is a high-performance homogeneous Ziegler catalyst. 2,3,4,5-Tetramethyl-4,5-dihydrocyclopenta[ b]thiophen-6-one was prepared without chromatography purification on the 40-g scale in a laboratory setting, from which the ligand precursor for 2 was obtained in 65% yield on a 50-g scale in a one-pot without the need for chromatography purification. Metallation was achieved in a high yield (78%) through reaction of the dilithiated compound with TiCl 4. Many derivatives were prepared by employing the same synthetic scheme as applied for 2. Among them, the titanium complex prepared from 2-methyl-4,5-dimethyl-6-(2- n-butyl-2,3,4,5-tetrahydroquinolin-8-yl)-4 H-cyclopenta[ b]thiophene exhibited an exceptionally high activity. Under commercially relevant high-temperature polymerization conditions (160 °C), this compound showed a higher activity than 2 (126 × 10 6 g/molTi?h versus 72 × 10 6 g/molTi?h), albeit with the formation of a polymer of slightly lower molecular weight ( M w, 159,000 versus 218,000) and with a slightly lower 1-octene content (9.3 mol% versus 12 mol%).
Abnormal Neural Processing during Emotional Salience Attribution of Affective Asymmetry in Patients with Schizophrenia
Seon-Koo Lee, Ji Won Chun, Jung Suk Lee, Hae-Jeong Park, Young-Chul Jung, Jeong-Ho Seok, Jae-Jin Kim
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0090792
Abstract: Aberrant emotional salience attribution has been reported to be an important clinical feature in patients with schizophrenia. Real life stimuli that incorporate both positive and negative emotional traits lead to affective asymmetry such as negativity bias and positivity offset. In this study, we investigated the neural correlates of emotional salience attribution in patients with schizophrenia when affective asymmetry was processed. Fifteen patients with schizophrenia and 14 healthy controls were scanned using functional magnetic resonance imaging (fMRI) while performing an emotion judgment task in which two pictures were juxtaposed. The task consisted of responding to affective asymmetry condition (ambivalent and neutral) and affective symmetry conditions (positive and negative), and group comparisons were performed for each condition. Significantly higher activity in the medial prefrontal cortex and inferior frontal gyrus was observed for the ambivalent condition than for the other conditions in controls, but not in patients. Compared with controls, patients showed decreased activities in the dorsolateral prefrontal cortex, dorsal anterior cingulate cortex, insula, and putamen for the ambivalent condition, but no changes were observed for the neutral condition. Multiple prefrontal hypoactivities during salience attribution of negativity bias in schizophrenia may underlie deficits in the integrative processing of emotional information. Regional abnormalities in the salience network may be the basis of defective emotional salience attribution in schizophrenia, which is likely involved in symptom formation and social dysfunction.
Effects of Band Therapy Using Music on Grasping Power, Depression, and Personal Relationships in Nursing-Home-Dwelling Elderly Individuals  [PDF]
Eun Kyung Chang, Heeok Park, Miran Jung, Hae Kyeong Lee, Jieun Park, Mijung Park, Minsuk Gang
Open Journal of Nursing (OJN) , 2016, DOI: 10.4236/ojn.2016.611092
Abstract: The current study examined the effects of band therapy using music on grasping power, depression, and personal relationships among residents of a nursing home. Thirty subjects participated in the study. The band therapy included greetings, warm-up exercises with music, singing with dance, playing instruments, closing speech, and stretching with background music. Band therapy was held for 40 minutes once per week, for a total of four sessions, in the activity room of the nursing home. Findings showed that grasping power, depression, and personal relationships were improved at posttest, but the differences were not statistically significant. A better study design to compare the effects of band therapy with the other group, and a more simple and repeated intervention for the elderly to follow without stress might be necessary.
Mpulse Breakdown Strength of Nano-ZnO/XLPE Nanocomposite Material on Temperature Rise  [PDF]
Min-Hae Park, Kee-Joe Lim
Modeling and Numerical Simulation of Material Science (MNSMS) , 2013, DOI: 10.4236/mnsms.2013.31B008
Abstract: Development of new materials using composite materials has been much interest. XLPE is a kind of power cable in high voltage insulation. Recently research for cable insulating material has shown that nano-size filler added to XLPE is electrically and physically stable. In this paper, Impulse strength was measured in XLPE that composite by adding na-no-ZnO with different mass proportions. There is positive and negative impulse voltage. However, there is no differ-ence between them on the film specimen. Therefore we tested only positive voltage. In order to understand temperature properties of XLPE nanocomposite sample, experiment of impulse breakdown strength were measured at room temper-ature and maximum allowable temperature (90℃). From this result, it can be considered that the breakdown strength of addition of th


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