e-Poster : Acute urticaria: histopathological analysis of 17 patients (초)

( Sang Hee Lee ),( Yuri Choi ),( Sang Eun Lee ),( Mi Ryung Roh ) 대한피부과학회 2010 초록집 Vol.48 No.20

Effects of Medicinal herb Extracts and their Components on Steatogenic Hepatotoxicity in Sk-hep1 Cells

Choi, You-Jin,Yoon, Yu-Jin,Choi, Ho-Sung,Park, So-Ra,Oh, Se-Hee,Jeong, Se-Mi,Suh, Hyo-Ryung,Lee, Byung-Hoon Korean Society of ToxicologyKorea Environmental Mu 2011 Toxicological Research Vol.27 No.4

Herbal medicines are widely used in many countries for the treatment of many diseases. Although the use of herb extracts as alternative medicine is growing, their toxicological properties have not been thoroughly investigated. In this study, we have investigated the effects of water and ethanol extracts of 18 herbs on the hepatic lipid metabolism and steatogenic hepatotoxicity. Ethanol extracts of Cirsium japonicum, Carthamus tinctorius, Rehmanniae glutinosa (preparata), Polygala tenuifolia, Foeniculum vulgare, Polygonum multiflorum, and Acorus gramineus and water extracts of Polygonum multiflorum and Rehmanniae glutinosa induced lipid accumulation in Sk-hep1 human hepatoma cells as determined by Nile red staining. These extracts increased the luciferase activity of sterol regulatory element (SRE) and decreased that of peroxisome proliferator response element (PPRE), indicating the possibilities of enhanced fatty acid synthesis and decreased fatty acid oxidation. To identify the components responsible for the fat accumulation, we tested 50 chemicals isolated from the nine herbs. Apigenin, luteolin, pectolinarin and lupeol from Cirsium japonicum, 8-methoxypsoralen and umbelliferone from Foeniculum vulgare and pomonic acid and jiocerebroside from Rehmanniae glutinosa significantly increased the accumulation of lipid droplets. These results suggest that ethanol extracts of Cirsium japonicum, Carthamus tinctorius, Rehmanniae glutinosa (preparata), Polygala tenuifolia, Foeniculum vulgare, Polygonum multiflorum, and Acorus gramineus and water extracts of Polygonum multiflorum and Rehmanniae glutinosa can cause fatty liver disease by decreasing ${\beta}$-oxidation of fatty acid and increasing lipogenesis.

Effect of Proton Beam Radiation on Bulbil Yield and Gibberellins of Chinese Yam(Dioscorea opposita Thunb.)

Sang-Kuk Kim,Hong-Jib Choi,Kye-Ryung Kim,In-Jung Lee,Hak-Yoon Kim 韓國作物學會 2011 Korean journal of crop science Vol.56 No.3

The study was carried out to evaluate the affect of proton beam radiation on production of bulbil and tuber including change of endogenous gibberellins, of Dioscorea opposita Thunb. The yield of bulbils and tubers from non- and irradiated D. opposita Thunb at doses of 5, 10, 15 and 20 Gy were determined. Endogenous gibberellins were also quantified by GC/MS analysis. D. opposita tubers irradiated at 15 Gy produced higher bulbil production than non-irradiated plants. Enlarged bulbil (above size diameter 4 mm) was significantly increased at 15 Gy. Bioactive endogenous GA4 was dominant in bulbils and tubers irradiated with proton beam rather than GA1 . Major gibberellins biosynthetic pathways in bulbils and tubers of D. opposita plants were non C-13 hydroxylation route. From the results of this study, 15 Gy proton beam radiation was suggested as an optimal dose that can produce high amounts of bulbil for mass production of D. opposita plant.

Prognostic Value of Metabolic Tumor Volume Measured by $^{18}F$-FDG PET/CT in Locally Advanced Head and Neck Squamous Cell Carcinomas Treated by Surgery

Choi, Kyu-Ho,Yoo, Ie-Ryung,Han, Eun-Ji,Kim, Yeon-Sil,Kim, Gi-Won,Na, Sae-Jung,Sun, Dong-Il,Jung, So-Lyung,Jung, Chan-Kwon,Kim, Min-Sik,Lee, So-Yeon,Kim, Sung-Hoon The Korea Society of Nuclear Medicine 2011 핵의학 분자영상 Vol.45 No.1

Purpose We assessed the prognostic value of metabolic tumor volume (MTV) measured using$^{18}F$-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) inpatients with locally advanced head and neck squamous cell carcinoma (HNSCC). $Methods$ We retrospectively reviewed 56 patients (51 men, five women; mean age $56.0{\pm}8.8$years) who had locally advanced HNSCC and underwent FDG PET/CT for initial evaluation. All patients had surgical resection and radiotherapy with or without concurrent chemotherapy. The peak standardized uptake value ($SUV_{peak}$) and MTV of the target lesion, including primary HNSCC andmetastatic cervical lymph nodes, were measured from FDG PET/CT images. We compared $SUV_{peak}$, MTV, and clinicopathologic variables such as age, Eastern Cooperative Oncology Group (ECOG) performance status, pN stage, pT stage, TNM stage, histologic grade and treatment modality to disease-free survival (DFS) and overall survival (OS). Results On the initial FDG PET/CT scans, the median $SUV_{peak}$ was 7.8 (range, 1.8-19.0) and MTV was17.0 $cm^3$ (range, 0.1-131.0 $cm^3$). The estimated 2-year DFS and OS rates were 67.2% and 81.8%. The cutoff points of $SUV_{peak}$ 6.2 and MTV 20.7 $cm^3$ were the best discriminative values for predicting clinical outcome. MTV and ECOG performance status were significantly related to DFS and OS on univariate and multivariate analyses (p<0.05). Conclusion The MTV obtained from initial FDG PET/CT scan is a significant prognostic factor for disease recurrence and mortality in locally advanced HNSCC treated with surgery and radiotherapy with or without chemotherapy.

The Neurological Safety of Epidural Pamidronate in Rats

Ryung Bok Lee,Yong Chul Kim,Chul Joong Lee,Hye Young Shin,Seung Yun Lee,Jong Cook Park,Yun Suk Choi,Chong Soo Kim,Sang Hyun Park 대한통증학회 2010 The Korean Journal of Pain Vol.23 No.2

Self-assembled block copolymer micelles with silver-carbon nanotube hybrid fillers for high performance thermal conduction

Choi, Jae Ryung,Yu, Seunggun,Jung, Haejong,Hwang, Sun Kak,Kim, Richard Hahnkee,Song, Giyoung,Cho, Sung Hwan,Bae, Insung,Hong, Soon Man,Koo, Chong Min,Park, Cheolmin The Royal Society of Chemistry 2015 Nanoscale Vol.7 No.5

<P>The development of polymer-filled composites with an extremely high thermal conductivity (TC) that is competitive with conventional metals is in great demand due to their cost-effective process, light weight, and easy shape-forming capability. A novel polymer composite with a large thermal conductivity of 153 W m(-1) K(-1) was prepared based on self-assembled block copolymer micelles containing two different fillers of micron-sized silver particles and multi-walled carbon nanotubes. Simple mechanical mixing of the components followed by conventional thermal compression at a low processing temperature of 160 C produced a novel composite with both structural and thermal stability that is durable for high temperature operation up to 150 C as well as multiple heating and cooling cycles of δT = 100 C. The high performance in thermal conduction of our composite was mainly attributed to the facile deformation of Ag particles during the mixing in a viscous thermoplastic medium, combined with networked carbon nanotubes uniformly dispersed in the nanoscale structural matrix of block copolymer micelles responsible for its high temperature mechanical stability. Furthermore, micro-imprinting on the composite allowed for topographically periodic surface micropatterns, which offers broader suitability for numerous micro-opto-electronic systems.</P>

A Survey on Recent Studies on Corporate Governance

Sung-hwan Choi(최성환),Jee-hoon Lee(이지훈),Dong-ryung Yang(양동령) 韓國經營史學會 2017 經營史學 Vol.82 No.-

This paper surveys the evolution of corporate governance issues influencing Korean public companies. The study first reviews literature presenting conventional explanations of why business groups prevails in certain countries, while in other countries, most of the companies exist as stand-alones with diversified ownership. The literature points out that benefits that controlling shareholders enjoy motivate the individuals to form the business groups. Individuals controlling entire business groups with limited stock ownership have incentives to pursue private benefits at the cost of minority shareholders. Such possibility necessitates an institution against corporate decisions hampering the rights of minority shareholders. Board of directors, especially outside directors, are supposed to monitor corporate insiders, in case that the insiders make decisions not beneficial to general shareholders. Such institutional requirement sometimes does not serve its original purpose as intended, when the insiders name outside directors who represent the best interest of the incumbent managers (or controlling individuals) not that of general shareholders. This caveat triggers the need of alternative channels by which minority shareholders directly participate in corporate decision making process. Recent rise of institutional investors, such as pension funds, private equities, and hedge funds, provides a new opportunity where the investment vehicles are directly vocal for or against corporate decisions. Such monitoring mechanism becomes more enforceable, as the monitoring is conducted not by agents (corporate directors) but directly by stockholders (institutional investors) holding significant portion of corporate. As a conclusion, we propose that the protection of minority shareholders becomes more effective when they find ways to directly participate in corporate decision process, compared to a situation where the shareholders designate an agent, such as outside directors, to make her protect their rights. 본 논문은 기업지배구조에 관하여 논한 최근 연구 결과물들을 고찰하였다. 기업지배구조에 관하여 다루어졌던 주요한 이슈들은 다음과 같다. 기업집단이 형성되는 이유, 기업 집단 형성에 따른 이익과 사회적 영향, 기업 이사회는 주주가치 보호라는 본래의 설립 취지를 살려 잘 운영되어 왔는지 여부, 최고 경영진에 대한 적절한 보상 수준, 최근의 기관투자자들의 투자자 행동주의의 효과 등이다. 일반적으로 기업지배집단은 여러 기업의 경영권을 유지하면서, 타인 자본 활용의 효과를 함께 활용하려는 최대주주에 의해 설립될 수 있다는 의견과 상대적으로 기업 활동을 보조하기 위한 사회적 인프라가 덜 갖추어진 국가에서 동일 기업 집단 내의 재무적, 인적 자원을 상호 활용하고자 하는 동인에서 설립된다는 논문들이 조사되었다. 최근 들어 급격히 성장하고 있는 최고경영진의 보상 수준에 대한 논문들은 그러한 보상 수준에 걸맞도록 최고경영진이 기업 가치상승에 도움을 주었는지를 주요 논점으로 다루고 있으며, 연구 결과는 이러한 문제에 대해 일관된 답을 주지 못하고 있는 것으로 판단된다. 최근 들어 급격히 성장한 대규모의 연금 펀드 및 사모펀드를 포함한 기관투자자들이 적극적으로 피투자회사의 경영에 관여하고 있는지 여부와 그러한 개입이 기업 가치 증대에 긍정적인 영향을 미치는 지에 대해 최근 많은 연구가 이루어져왔다. 전반적으로 사모펀드 등은 적극적 개입을 통해 주주 가치 극대화를 추구하는 경향이 있는 반면, 연금 펀드 등은 경영 참여 등을 자제하는 동시에 투자 수익률의 극대화를 소극적으로 추진하는 것으로 판단된다. 이러한 기존 논문들에 대한 고찰은 기업 지배구조에 관한 여러 가지 규제 및 제도의 도입을 고려하고 있는 현재 한국의 실정을 고려할 때, 각 규제 혹은 제도가 미칠 수 있는 잠재적 영향을 여러 각도에서 고찰할 수 있는 기회를 제공한다는 측면에서 의의를 찾을 수 있다.

Quantification of Thioguanine in DNA Using Liquid Chromatography-Tandem Mass Spectrometry for Routine Thiopurine Drug Monitoring in Patients With Pediatric Acute Lymphoblastic Leukemia

Choi Rihwa,Chun Mi Ryung,Park Jisook,이지원,Ju Hee Young,Cho Hee Won,Hyun Ju Kyung,Koo Hong Hoe,Yi Eun Sang,Lee Soo-Youn 대한진단검사의학회 2021 Annals of Laboratory Medicine Vol.41 No.2

Background: We developed an assay to measure DNA-incorporated 6-thioguanine (DNA-TG) and validated its clinical applicability in Korean pediatric patients with acute lymphoblastic leukemia (ALL) in order to improve individualized thiopurine treatment and reduce the life-threatening cytotoxicity. Methods: The DNA-TG assay was developed based on liquid chromatography-tandem mass spectrometry, with isotope-labeled TG-d3 and guanine-d3 as internal standards. This method was applied to 257 samples of pediatric ALL patients. The DNA-TG level was compared with erythrocyte TG nucleotide (RBC-TGN) level in relation to the TPMT and NUDT15 genotypes, which affect thiopurine metabolism, using Spearman’s rank test and repeated measure ANOVA. Results: For DNA-TG quantification, a linearity range of 10.0-5,000.0 fmol TG/μg DNA; bias for accuracy of –10.4% –3.5%; coefficient of variation for intra- and inter-day precision of 3.4% and 5.8% at 80 fmol TG/μg DNA and of 4.9% and 5.3% at 800 fmol TG/μg DNA, respectively; and recovery of 85.7%-116.2% were achieved without matrix effects or carry-over. The median DNA-TG level in the 257 samples was 106.0 fmol TG/μg DNA (interquartile range, 75.8-150.9). There was a strong correlation between DNA-TG and RBC-TGN levels (ρ=0.68, P<0.0001). The DNA-TG/RBC-TGN ratio was significantly higher in NUDT15 intermediate metabolizers (*1/*2 and *1/*3) than in patients with wild-type alleles (P<0.0001). Conclusions: This simple and sensitive method for measuring DNA-TG level can improve therapeutic drug monitoring for thiopurine treatment.

Characteristics and Clinical Outcomes of Congenital Myenteric Hypoganglionosis (CMH) in Children

Sung-Ryung Choi,Dayoung Ko,Jaemoon Koh,Hyun-Young Kim 대한외과학회 2023 대한외과학회 학술대회 초록집 Vol.2023 No.5

Pathogenic microorganisms, heavy metals, and antibiotic residues in seven Korean freshwater aquaculture species

Choi, Jae-Suk,Park, Sun-Mee,Kim, Young Hun,Oh, Sang Cheol,Lim, Eun Seo,Hong, Yong-Ki,Kim, Mi-Ryung Korean Society of Food Science and Technology 2016 Food Science and Biotechnology Vol.25 No.5

This survey was performed to estimate the levels of pathogenic microorganisms, antibiotic residues, and heavy metals in seven Korean freshwater aquaculture species including Anguilla japonica, Cyprinus carpio nudus, Oncorhynchus mykiss, Pseudobagrus fulvidraco, Semisulcospira coreana, Silurus asotus, and Trionyxs sinensis. None of the ten foodborne pathogens tested in this study were found in any of the species collected from any of the aquaculture farms. Furthermore, no banned chemicals or antibiotic residues were found in any of the species collected from any of the aquaculture farms, except enrofloxacin, which was below guideline limits (0.1 mg/kg). Finally, no species had lead, cadmium, total arsenic, or total mercury concentrations above the Ministry of Food and Drug Safety (MSDF) guidelines (0.5, 0.5, 0.1, and 0.5 mg/kg, respectively). These results ensure the safety of freshwater aquaculture species and will be useful for developing consumption advisories of freshwater fishes.