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Search Results: 1 - 10 of 21187 matches for " Kwang Hoon Song "
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Insights into the Molecular Evolution of HslU ATPase through Biochemical and Mutational Analyses
Kwang Hoon Sung, Hyun Kyu Song
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0103027
Abstract: The ATP-dependent HslVU complexes are found in all three biological kingdoms. A single HslV protease exists in each species of prokaryotes, archaea, and eukaryotes, but two HslUs (HslU1 and HslU2) are present in the mitochondria of eukaryotes. Previously, a tyrosine residue at the C-terminal tail of HslU2 has been identified as a key determinant of HslV activation in Trypanosoma brucei and a phenylalanine at the equivalent position to E. coli HslU is found in T. brucei HslU1. Unexpectedly, we found that an F441Y mutation in HslU enhanced the peptidase and caseinolytic activity of HslV in E. coli but it showed partially reduced ATPase and SulA degradation activity. Previously, only the C-terminal tail of HslU has been the focus of HslV activation studies. However, the Pro315 residue interacting with Phe441 in free HslU has also been found to be critical for HslV activation. Hence, our current biochemical analyses explore the importance of the loop region just before Pro315 for HslVU complex functionality. The proline and phenylalanine pair in prokaryotic HslU was replaced with the threonine and tyrosine pair from the functional eukaryotic HslU2. Sequence comparisons between multiple HslUs from three different biological kingdoms in combination with biochemical analysis of E. coli mutants have uncovered important new insights into the molecular evolutionary pathway of HslU.
Prevalence of Metabolic Syndrome according to Sasang Constitutional Medicine in Korean Subjects
Kwang Hoon Song,Sung-Gon Yu,Jong Yeol Kim
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/646794
Abstract: Metabolic syndrome (MS) is a complex disorder defined by a cluster of abdominal obesity, atherogenic dyslipidemia, hyperglycemia, and hypertension; the condition is recognized as a risk factor for diabetes and cardiovascular disease. This study assessed the effects of the Sasang constitution group (SCG) on the risk of MS in Korean subjects. We have analyzed 1,617 outpatients of Korean oriental medicine hospitals who were classified into three SCGs, So-Yang, So-Eum, and Tae-Eum. Significant differences were noted in the prevalence of MS and the frequencies of all MS risk factors among the three SCGs. The odds ratios for MS as determined via multiple logistic regression analysis were 2.004 for So-Yang and 4.521 for Tae-Eum compared with So-Eum. These results indicate that SCG may function as a significant risk factor of MS; comprehensive knowledge of Sasang constitutional medicine may prove helpful in predicting susceptibility and developing preventive care techniques for MS.
Association of the Apolipoprotein A5 Gene ?1131T>C Polymorphism with Serum Lipids in Korean Subjects: Impact of Sasang Constitution
Kwang Hoon Song,Sung-Gon Yu,Seongwon Cha,Jong Yeol Kim
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/598394
Abstract: Apolipoprotein A5 (APOA5) was identified as a strong modulator of serum lipids. Moreover, an APOA5 gene −1131T>C polymorphism has been associated with serum lipids, but the results are inconsistent according to ethnic and racial groups. We have genotyped and analyzed 1,619 outpatients of Korean oriental medicine hospitals who were classified into three Sasang constitution groups (SCGs), So-Yang (SY), So-Eum (SE), and Tae-Eum (TE). There were no significant difference in the distribution of the APOA5 −1131T>C genotype among the three SCGs. Subjects with the C allele in SY and TE showed significantly lower serum high-density lipoprotein cholesterol (HDL-C) and higher triglyceride (TG) levels than noncarriers of the C allele. These results show the differences in the prevalence of decreasing serum HDL-C and elevating serum TG levels along with APOA5 −1131T>C polymorphism according to SCG and suggest that SCG may act as a significant risk factor for hypo-HDL-C-emia and hypertriglyceridemia susceptibility.
Reconstruction of the Head and Neck Region Using Lower Trapezius Musculocutaneous Flaps
Soo Kwang Yoon,Seung Han Song,Nakheon Kang,Yeo-Hoon Yoon
Archives of Plastic Surgery , 2012, DOI: http://dx.doi.org/10.5999/aps.2012.39.6.626
Abstract: Background Recent literature has indicated that free flaps are currently considered thepreferred choice for head and neck reconstruction. However, head and neck cancer patients arefrequently treated with chemoradiotherapy, which is often associated with a poor general andlocal condition, and thus, such patients are ineligible for free flap reconstruction. Therefore,other reconstruction modalities should be considered.Methods We used lower trapezius musculocutaneous (LTMC) flap based on the dorsal scapularartery to reconstruct head and neck defects that arose from head and neck cancer in 8 patients.All of the patients had undergone preoperative chemoradiotherapy.Results There were no complications except one case of partial flap necrosis; it was treatedwith secondary intention. Healing in the remaining patients was uneventful without hematoma,seroma, or infection. The donor sites were closed primarily.Conclusions The LTMC flap is the preferred flap for a simple, reliable, large flap with a widearc of rotation and minor donor-site morbidity. The authors recommend this versatile islandflap as an alternative to microvascular free tissue transfer for the reconstruction of defects inthe head and neck region, for patients that have undergone preoperative chemoradiotherapy.
Geometrically Controlled Asymmetric Division of CD4+ T Cells Studied by Immunological Synapse Arrays
Hong-Ryul Jung, Kwang Hoon Song, John T. Chang, Junsang Doh
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0091926
Abstract: Similar to stem cells, na?ve T cells undergo asymmetric division following activation. While asymmetric division of T cells has been shown to be an important mechanism for the generation of lymphocyte fate diversity during immune responses, key factors that influence whether T cells will undergo symmetric or asymmetric divisions are not completely understood. Here, we utilized immunological synapse arrays (ISAs) to begin to dissect mechanisms of asymmetric T lymphocyte division. ISAs are protein micropatterned surfaces composed of two segregated regions, activation sites and adhesion fields. Activation sites are small spots presenting activation signals such as anti-CD3 and anti-CD28, and adhesion fields are the remaining regions surrounding activation sites immobilized with interintercel adhesion molecule 1 (ICAM-1). By varying the size and the distance between the activation sites and measuring the incidence of asymmetric cell divisions, we found that the distance between activation sites is an important regulator of asymmetric division. Further analysis revealed that more symmetric divisions occurred when two nascent daughter cells stably interacted with two distinct activation sites throughout and following cytokinesis. In contrast, more asymmetric divisions occurred when only one daughter cell remained anchored on an activation site while the other daughter became motile and moved away following cytokinesis. Together, these results indicate that TCR signaling events during cytokinesis may repolarize key molecules for asymmetric partitioning, suggesting the possibility that the density of antigen presenting cells that interact with T cells as they undergo cytokinesis may be a critical factor regulating asymmetric division in T cells.
In Vitro and In Vivo Genotoxicity Assessment of Aristolochia manshuriensis Kom.
Youn-Hwan Hwang,Taesoo Kim,Won-Kyung Cho,Hye Jin Yang,Dong Hoon Kwak,Hyunil Ha,Kwang Hoon Song,Jin Yeul Ma
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/412736
Abstract: Arisolochiae species plants containing aristolochic acids I and II (AA I and AA II) are well known to cause aristolochic acid nephropathy (AAN). Recently, there are various approaches to use AAs-containing herbs after the removal of their toxic factors. However, there is little information about genotoxicity of Arisolochiae manshuriensis Kom. (AMK) per se. To obtain safety information for AMK, its genotoxicity was evaluated in accordance with OECD guideline. To evaluate genotoxicity of AMK, we tested bacterial reverse mutation assay, chromosomal aberration test, and micronucleus test. Here, we also determined the amounts of AA I and II in AMK (2.85 ± 0.08 and 0.50 ± 0.02 mg/g extract, resp.). In bacterial reverse mutation assay, AMK dose-dependently increased revertant colony numbers in TA98, TA100 and TA1537 regardless of metabolic activation. AMK increased the incidence of chromosomal aberration in Chinese hamster ovary-K1 cells, but there was no statistically significant difference. The incidences of micronucleus in bone marrow erythrocyte were significantly increased in mice after oral administration of AMK (5000 mg/kg), comparing with those of vehicle group (<0.05). The results of three standard tests suggest that the genotoxicity of AMK is directly related to the AAs contents in AMK.
A Novel Herbal Medicine KIOM-MA Exerts an Anti-Inflammatory Effect in LPS-Stimulated RAW 264.7 Macrophage Cells
You-Chang Oh,Won-Kyung Cho,Yun Hee Jeong,Ga Young Im,Aeyung Kim,Youn-Hwan Hwang,Taesoo Kim,Kwang Hoon Song,Jin Yeul Ma
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/462383
Abstract: KIOM-MA was recently reported as a novel herbal medicine effective for atopic dermatitis and asthma. In this study, we have demonstrated the inhibitory effect of KIOM-MA on proinflammatory mediator produced in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. KIOM-MA significantly inhibited the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) as well as nitric oxide (NO) and prostaglandin E2 (PGE2). Consistent with the inhibitory effect on PGE2, KIOM-MA suppresses the LPS-induced migration of macrophages and gelatinase activity and the expression of matrix metalloprotease-9 (MMP-9) in a dose-dependent manner. Additionally, KIOM-MA showed a strong suppressive effect on the inflammatory cytokines production such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). We also found that KIOM-MA inhibits the activation of nuclear factor-κB (NF-κB) and represses the activity of extracellular signal-regulated kinase (ERK), p38, and c-Jun NH2-terminal kinase (JNK) mitogen-activated protein kinases (MAPKs). Taken together, we elucidated the mechanism of anti-inflammatory effect of KIOM-MA using RAW 264.7 cells stimulated by LPS.
Performance of Transient Elastography for the Staging of Liver Fibrosis in Patients with Chronic Hepatitis B: A Meta-Analysis
Young Eun Chon, Eun Hee Choi, Ki Jun Song, Jun Yong Park, Do Young Kim, Kwang-Hyub Han, Chae Yoon Chon, Sang Hoon Ahn, Seung Up Kim
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0044930
Abstract: Background Transient elastography (TE), a non-invasive tool that measures liver stiffness, has been evaluated in meta-analyses for effectiveness in assessing liver fibrosis in European populations with chronic hepatitis C (CHC). However, these data cannot be extrapolated to populations in Asian countries, where chronic hepatitis B (CHB) is more prevalent. In this study, we performed a meta-analysis to assess the overall performance of TE for assessing liver fibrosis in patients with CHB. Methods Studies from the literature and international conference abstracts which enrolled only patients with CHB or performed a subgroup analysis of such patients were enrolled. Combined effects were calculated using area under the receiver operating characteristic curves (AUROC) and diagnostic accuracy values of each study. Result A total of 18 studies comprising 2,772 patients were analyzed. The mean AUROCs for the diagnosis of significant fibrosis (F2), severe fibrosis (F3), and cirrhosis (F4) were 0.859 (95% confidence interval [CI], 0.857–0.860), 0.887 (95% CI, 0.886–0.887), and 0.929 (95% CI, 0.928–0.929), respectively. The estimated cutoff for F2 was 7.9 (range, 6.1–11.8) kPa, with a sensitivity of 74.3% and specificity of 78.3%. For F3, the cutoff value was determined to be 8.8 (range, 8.1–9.7) kPa, with a sensitivity of 74.0% and specificity of 63.8%. The cutoff value for F4 was 11.7 (range, 7.3–17.5) kPa, with a sensitivity of 84.6% and specificity of 81.5%. Conclusion TE can be performed with good diagnostic accuracy for quantifying liver fibrosis in patients with CHB.
Abnormal Liver Stiffness Assessed Using Transient Elastography (Fibroscan?) in HIV-Infected Patients without HBV/HCV Coinfection Receiving Combined Antiretroviral Treatment
Sang Hoon Han, Seung Up Kim, Chang Oh Kim, Su Jin Jeong, Jun Yong Park, Jun Yong Choi, Do Young Kim, Sang Hoon Ahn, Young Goo Song, Kwang-Hyub Han, June Myung Kim
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0052720
Abstract: Background and Aims Liver stiffness measurement (LSM) using transient elastography (Fibroscan?) can identify individuals with potential underlying liver disease. We evaluated the prevalence of abnormal LSM values as assessed using LSM and its predictors in HIV-infected asymptomatic patients receiving combined antiretroviral treatment (cART) without HBV/HCV coinfection. Methods We prospectively recruited 93 patients who had consistently been undergoing cART for more than 12 months at Severance Hospital in Seoul, Republic of Korea, from June to December 2010. LSM values >5.3 kPa were defined as abnormal. Results Thirty-nine (41.9%) had abnormal LSM values. On multivariate correlation analysis, the cumulative duration of boosted and unboosted protease inhibitors (PIs) were the independent factors which showed a negative and positive correlation to LSM values, respectively (β = –0.234, P = 0.023 and β = 0.430, P<0.001). In multivariate logistic regression analysis, the cumulative exposure duration of boosted-PIs and γ-glutamyltranspeptidase levels were selected as the independent predictors which showed a negative and positive correlation with abnormal LSM values, respectively (odds ratio [OR], 0.941; 95% confidence interval [CI], 0.889–0.997; P = 0.039 and OR, 1.032; 95% CI, 1.004–1.060; P = 0.023). Conclusion The high percentage of HIV-infected asymptomatic patients receiving cART without HBV/HCV coinfection had abnormal LSM values. The cumulative exposure duration of boosted-PIs and γ-GT level were independent predictors which showed a negative and positive correlation with abnormal LSM values, respectively.
Liver Stiffness Value-Based Risk Estimation of Late Recurrence after Curative Resection of Hepatocellular Carcinoma: Development and Validation of a Predictive Model
Kyu Sik Jung, Ji Hong Kim, Seung Up Kim, Kijun Song, Beom Kyung Kim, Jun Yong Park, Do Young Kim, Sang Hoon Ahn, Do Chang Moon, In Ji Song, Gi Hong Choi, Young Nyun Park, Kwang-Hyub Han
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0099167
Abstract: Background Preoperative liver stiffness (LS) measurement using transient elastography (TE) is useful for predicting late recurrence after curative resection of hepatocellular carcinoma (HCC). We developed and validated a novel LS value-based predictive model for late recurrence of HCC. Methods Patients who were due to undergo curative resection of HCC between August 2006 and January 2010 were prospectively enrolled and TE was performed prior to operations by study protocol. The predictive model of late recurrence was constructed based on a multiple logistic regression model. Discrimination and calibration were used to validate the model. Results Among a total of 139 patients who were finally analyzed, late recurrence occurred in 44 patients, with a median follow-up of 24.5 months (range, 12.4–68.1). We developed a predictive model for late recurrence of HCC using LS value, activity grade II-III, presence of multiple tumors, and indocyanine green retention rate at 15 min (ICG R15), which showed fairly good discrimination capability with an area under the receiver operating characteristic curve (AUROC) of 0.724 (95% confidence intervals [CIs], 0.632–0.816). In the validation, using a bootstrap method to assess discrimination, the AUROC remained largely unchanged between iterations, with an average AUROC of 0.722 (95% CIs, 0.718–0.724). When we plotted a calibration chart for predicted and observed risk of late recurrence, the predicted risk of late recurrence correlated well with observed risk, with a correlation coefficient of 0.873 (P<0.001). Conclusion A simple LS value-based predictive model could estimate the risk of late recurrence in patients who underwent curative resection of HCC.
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