Young Jin Choi

MEDIPOST Biomedical Research Institute, Sŏul, Seoul, South Korea

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Publications (145)302.05 Total impact

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    ABSTRACT: Aggregation of unstable particles in water limits the application of lipid nanoparticle (LNP) systems to foods despite the capability to encapsulate lipophilic bioactive components. Here, we exploit a preparation process that can reduce the aggregation of LNPs. Sonication during the cooling step (post-sonication) for 4, 5 or 6 min was applied to increase the covering effect of Tween 20 on the particle. Additionally, LNPs were prepared using fully hydrogenated canola oil (FHCO) blended with 0-30 wt% liquid canola oil (LCO) of the lipid phase. Surfactant surface load data indicate that the post-sonication might make non-emulsifying Tween 20 diffuse from aqueous phase to droplet surfaces, which could decrease the crystallinity index (CI) of LNPs due to the inhibition of lipid crystallization. Moreover, the LCO content in lipid matrix could decrease the CI, which could reduce forming hydrophobic patches on the particle surface. Therefore, the post-sonication and the LCO addition in the matrix could effectively prevent the aggregation among hydrophobic patches. This improved colloidal stability of LNPs was verified by the particle shape in transmission electron microscopy and the gelation test. Consequently, LNPs fabricated using 6 min post-sonication and 30 wt% LCO in the lipid exhibited the greatest stability (size: 202.3 nm; CI: 57.5%; and Tween 20 surface load: 10.29 mg m-2).This study may serve as a basis for further researches that aim to develop delivery systems for functional foods.
    Journal of agricultural and food chemistry. 11/2014;
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    ABSTRACT: The fabrication of 3 × 3 crossbar arrays measuring 20 μm in width was demonstrated. The bipolar resistive switching characteristics in manganese oxide nanoparticles were investigated in the crossbar structure of top electrode (Au)/nanoparticle assembly/bottom electrode (Ti) on SiO2/Si substrate. The monodisperse manganese oxide nanoparticles measuring 13 nm in diameter were chemically synthesized by thermal decomposition of manganese acetate in the presence of oleic acid at high temperature. The nanoparticles were assembled as a layer measuring 30 nm thick by repeated dip-coating and annealing steps. The Au/nanoparticle assembly/Ti devices performed the bipolar behavior associated with the formation and sequential rupture of multiple conducting filaments in applying bias on Au electrode. When the voltage was swept from to +5 V to the Au top electrode, the reset voltage was observed at ∼4.4 V. As the applied voltage swept from 0 to −5 V, the set voltage occurred at ∼−1.8 V.
    Journal of Nanoscience and Nanotechnology 11/2014; 14(11). · 1.15 Impact Factor
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    ABSTRACT: Hysteresis and threshold switching characteristics were investigated in the indium-gallium-zinc-oxide (IGZO) thin-film-transistors (TFTs) with inserted Pt-Fe2O3 core–shell nanocrystals (NCs) layer between source/drain and IGZO channel. The output curves showed the hysteresis with threshold drain voltage and the transfer curves showed the hysteresis with the shift of threshold gate voltage. These hysteresis, threshold switching, and shift of threshold voltage in both output and transfer curves are caused by charging of inserted NCs. These unique features demonstrated the memory and on/off switching operation by controlling both threshold gate and drain voltages through charging NCs.
    Semiconductor Science and Technology 11/2014; 29(11). · 1.92 Impact Factor
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    ABSTRACT: Double-layered microparticles for enzyme-triggered release in the gastrointestinal tract were prepared by spray-chilling a water/oil/water emulsion, which could be a promising candidate for the targeted delivery of water-soluble bioactive compounds. Based on response surface methodology, the optimum conditions for 2nd emulsifier content, concentration ratio of the single emulsion to the coating material, and dispersion fluid temperature were 201.5μmol, 0.30, and 10.1°C, respectively. Morphological characterisation using an FE-SEM indicated that double-layered microparticles with diameters of 7-10μm were spherical and possessed scores of inner droplets. Release profiles generated using in vitro digestion models revealed that the core of double-layered microparticles was gradually released by enzymatic degradation when exposed to the simulated intestinal environment. The accumulative release reached 59.8±0.2% within a residence time of 3h, whereas they were resistant to gastric release-stimuli, such as extremely low pH and pepsin (below 2.4±0.6%).
    Food Chemistry. 10/2014; 161:53–59.
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    ABSTRACT: We observed giant enhancement of Raman intensity from 4-Mpy molecules adsorbed on semiconducting one-dimensional ZnO nanostructures, nanowires and nanocones, without involving any noble metals. Interestingly, the enhancement is strongly dependent on the geometry of ZnO nanostructures and can mainly be explained by the cavity-like structural resonance of the electric field. Our results can be applied to systematically create hot spots for Raman signal enhancement using one-dimensional semiconducting nanomaterials.
    Nanoscale 10/2014; · 6.73 Impact Factor
  • Microelectronic Engineering 09/2014; 127:40–43. · 1.22 Impact Factor
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    ABSTRACT: The aim of this study is to identify the prognostic factors of distant metastasis (DM) after induction chemotherapy (IC) followed by concurrent chemoradiotherapy (CRT) for locoregionally advanced head and neck cancer (HNC).
    Cancer research and treatment : official journal of Korean Cancer Association. 08/2014;
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    ABSTRACT: Long-term outcomes are imperative to confirm safety of drug-eluting stents. There have been 2 randomized controlled trials comparing everolimus-eluting stents (EESs) and Resolute zotarolimus-eluting stents (ZES-Rs). To date, long-term clinical outcomes of these stents were limited to only 1 report, which has recently reported 4-year comparisons of these stents. Therefore, more evidence is needed regarding long-term clinical outcomes of the second-generation stents. This study compared the long-term clinical outcomes of EES with ZES-R in "all-comer" cohorts up to 3-year follow-up. The EXCELLENT and RESOLUTE-Korea registries prospectively enrolled 3,056 patients treated with EES and 1,998 with ZES-R, respectively, without exclusions. Stent-related composite outcomes (target lesion failure) and patient-related composite events up to 3-year follow-up were compared in crude and propensity score-matched analyses. Of 5,054 patients, 3,830 patients (75.8%) had off-label indication (2,217 treated with EES and 1,613 treated with ZES-R). The stent-related outcome (189 [6.2%] vs 127 [6.4%], p = 0.812) and the patient-related outcome (420 [13.7%] vs 250 [12.5%], p = 0.581) did not differ between EES and ZES-R, respectively, at 3 years, which was corroborated by similar results from the propensity score-matched cohort (hazard ratio [HR] 0.92, 95% confidence interval [CI] 0.70 to 1.20, p = 0.523 and 0.85, 95% CI 0.70 to 1.02, p = 0.081, for stent- and patient-related outcomes, respectively). The rate of definite or probable stent thrombosis up to 3 years (22 [0.7%] vs 10 [0.5%], p = 0.370) was also similar. The rate of very late definite or probable stent thrombosis was very low and comparable between the 2 stents (3 [0.1%] vs 1 [0.1%], p = 0.657). In multivariate analysis, chronic renal failure (adjusted HR 3.615, 95% CI 2.440 to 5.354, p <0.001) and off-label indication (adjusted HR 1.782, 95% CI 1.169 to 2.718, p = 0.007) were the strongest predictors of target lesion failure at 3 years. In conclusion, both stents showed comparable safety and efficacy at 3-year follow-up in this robust real-world registry with unrestricted use of EES and ZES-R. Overall incidences of target lesion failure and definite stent thrombosis, including very late stent thrombosis, were low, even in the patients with off-label indications, suggesting excellent long-term safety and sustained efficacy of both types of second-generation drug-eluting stents.
    The American Journal of Cardiology 08/2014; · 3.21 Impact Factor
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    ABSTRACT: To evaluate the efficacy of hydromorphone-OROS (HM-OROS) in reducing sleep disturbance and relieving cancer pain.
    Cancer research and treatment : official journal of Korean Cancer Association. 07/2014;
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    ABSTRACT: Lycopene is a natural antioxidant which has several health benefits. Undesirable oxidation of lycopene compromises its health benefits and also affects the sensory quality of food products containing lycopene. Health benefits associated with lycopene in food preparations can be enhanced by preventing its degradation by incorporating it into the oil phase of an oil-in-water nanoemulsion. In this study, lycopene nanoemulsions were prepared from a low-concentration lycopene extract using an emulsification–evaporation technique. The effects of the concentrations of the lycopene extract (0.015 to 0.085 mg/mL) and emulsifier (0.3 to 0.7 mg/mL), and the number of homogenization cycles (2 to 4) on the droplet size, emulsification efficiency (EE), and nanoemulsion stability were investigated and optimized by statistical analysis using a Box-Behnken design. Regression analysis was used to determine the 2nd-order polynomial model relationship of independent and dependent variables, with multiple regression coefficients (R2) of 0.924, 0.933, and 0.872, for the droplet size, EE, and nanoemulsion stability, respectively. Analysis of variance showed that the lycopene extract concentration has the most significant effect on all the response variables. Response surface methodology predicted that a formulation containing 0.085 mg/mL of lycopene extract and 0.7 mg/mL of emulsifier, subjected to 3 homogenization cycles, is optimal for achieving the smallest droplet size, greatest emulsion stability, and acceptable EE. The observed responses were in agreement with the predicted values of the optimized formulation. This study provided important information about the statistical design of lycopene nanoemulsion preparation.Practical ApplicationLycopene nanoemulsions have potential applications in supplementing various food matrices, especially beverages since it can provide transparency in appearance. The novelty of this study is to prepare highly transparent lycopene emulsion which is preferable for the liquid food application since it is less effective in distorting optical appearance of the products. The lycopene nanoemulsion with droplets less than 100 nm is highly transparent compared to unencapsulated lycopene extract, which makes beverage turbid.
    Journal of Food Science 07/2014; · 1.78 Impact Factor
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    ABSTRACT: Background Colorectal cancer (CRC) is the fourth leading cause of cancer-related deaths worldwide. The combination of oxaliplatin-based treatments (oxaliplatin plus infusional 5-fluorouracil and leucovorin [FOLFOX] or oxaliplatin plus capecitabine [CapeOX]) and bevacizumab is a standard chemotherapy regimen for metastatic CRC (mCRC). However, several clinical studies that tested S-1 plus oxaliplatin (SOX) indicate that SOX is also a treatment option for mCRC. TSU-68 is an oral compound that inhibits vascular endothelial growth factor receptor and platelet-derived growth factor receptor. The recommended dose of TSU-68 + SOX was previously determined in a phase I study of mCRC patients. The goal of this trial was to evaluate the efficacy of TSU-68 in combination with SOX. Methods This open-label multicenter randomized phase II trial was performed in Korea. Treatment-naive mCRC patients with a performance status of 0 or 1 were randomized in a 1:1 ratio to receive either TSU-68 + SOX or SOX alone. The primary endpoint was progression-free survival (PFS). Results A total of 105 patients (TSU-68 + SOX, 52 patients; SOX alone, 53 patients) were randomized. The median PFS was 7.0 months in the TSU-68 + SOX group (hazard ratio [HR], 1.057) and 7.2 months in the SOX group (p = 0.8401). The most frequent grade 3 and 4 adverse events were thrombocytopenia (9.6 % [TSU-68 + SOX] vs. 26.4 % [SOX]), neutropenia (13.5 % [TSU-68 + SOX] vs. 15.1 % [SOX]), and anemia (3.8 % [TSU-68 + SOX] vs. 13.2 % [SOX]). We observed a difference between the 2 groups for all grades of anemia (15.4 % [TSU-68 + SOX] vs. 32.1 % [SOX]), diarrhea (30.8 % [TSU-68 + SOX] vs. 47.2 % [SOX]), vomiting (50.0 % [TSU-68 + SOX] vs. 26.4 % [SOX]), and chromaturia (23.1 % [TSU-68 + SOX] vs. 0.0 % [SOX]). Analysis using a Cox proportional hazard model showed that baseline interleukin 6 (IL-6) levels were associated with a survival benefit of TSU-68 (p = 0.012). Conclusion TSU-68 + SOX had a favorable safety profile. However, TSU-68 did not have a synergistic effect on the efficacy of SOX. The baseline serum IL-6 level could be a prognostic factor for TSU-68 efficacy.
    Investigational New Drugs 02/2014; · 3.50 Impact Factor
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    ABSTRACT: The extraction of medicinal or functional compounds from herbal plants is an important unit operation in food and bio-industries. The target compounds are generally present inter- or intra-cellularly in an intricate microstructure formed by cells, intercellular spaces, capillaries, and pores. The major resistance of molecular diffusion in materials of plant origin always comes from the intact cell walls and adhering membranes. Therefore, increasing the permeability of cell walls and membranes plays a very important role to increase extraction yield and/or extraction rate. Important pretreatment methods to modify the cellular structures and increase the permeability of cell walls or membranes are discussed in this paper. They include physical, biologic, and chemical treatments. In physical methods, mechanical disruption, high-pressure (HP) process, pulsed electric field (PEF) application, ultrasonic treatment, and freeze-thaw, and so on were applied. In biologic methods, different cell wall-degrading enzymes were applied to break-down cell walls or membranes and to diminish the overall internal resistance for transporting bioactive compounds from internal matrix to the external solution. In chemical methods, various chemicals for increasing the inner- or outer-membrane permeabilization were introduced. The principles of the technologies, examples of improvements, and advantages and disadvantages of the pretreatment methods are critically reviewed in this paper.
    Critical reviews in food science and nutrition 01/2014; 54(10):1283-97. · 3.73 Impact Factor
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    ABSTRACT: We conducted a prospective multicenter study identifying the role of bortezomib in patients with relapsed or refractory plasma cell myeloma (PCM) in bone resorption and formation via bone turnover markers. A total of 104 patients received at least 1 cycle of bortezomib. Most of them had advanced disease (n = 89). Among them, 75 patients completed 4 cycles of treatment. Most of the patients (81.7%) were treated in combination with steroid. After the 4th cycle treatment, 47 of 75 patients achieved CR, nCR, VGPR, and PR (64.4%), while 26 patients achieved less than PR (35.6%). The proportion of patients who achieved ≥ PR increased as patients received more treatment cycles, reaching 90% after the 8th cycle. DKK-1 levels decreased significantly posttreatment. Bone formation markers (bALP and OC) and osteoclast regulator such as sRANKL also decreased significantly. These findings were observed primarily in patients who received steroid and who had a longer disease duration. While sRANKL demonstrated significant reduction posttreatment, osteoprotegerin (OPG) level did not significantly change posttreatment, resulting in a decreased sRANKL/OPG ratio (P = 0.037). In conclusion, our clinical data suggest that treatment with bortezomib and steroid may rearrange the metabolic balance between osteoblast and osteoclast activities in PCM.
    BioMed Research International 01/2014; 2014:245247. · 2.71 Impact Factor
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    ABSTRACT: We assessed the success rate of empirical antifungal therapy with itraconazole and evaluated risk factors for predicting the failure of empirical antifungal therapy. A multicenter, prospective, observational study was performed in patients with hematological malignancies who had neutropenic fever and received empirical antifungal therapy with itraconazole at 22 centers. A total of 391 patients who had abnormal findings on chest imaging tests (31.0%) or a positive result of enzyme immunoassay for serum galactomannan (17.6%) showed a 56.5% overall success rate. Positive galactomannan tests before the initiation of the empirical antifungal therapy (P=0.026, hazard ratio [HR], 2.28; 95% confidence interval [CI], 1.10-4.69) and abnormal findings on the chest imaging tests before initiation of the empirical antifungal therapy (P=0.022, HR, 2.03; 95% CI, 1.11-3.71) were significantly associated with poor outcomes for the empirical antifungal therapy. Eight patients (2.0%) had premature discontinuation of itraconazole therapy due to toxicity. It is suggested that positive galactomannan tests and abnormal findings on the chest imaging tests at the time of initiation of the empirical antifungal therapy are risk factors for predicting the failure of the empirical antifungal therapy with itraconazole. (Clinical Trial Registration on National Cancer Institute website, NCT01060462).
    Journal of Korean medical science 01/2014; 29(1):61-8. · 0.84 Impact Factor
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    ABSTRACT: Objectives We sought to evaluate the impact of final kissing balloon inflation (FKBI) after simple stent implantation for the treatment of non-left main true coronary bifurcation lesions in patients with acute coronary syndrome (ACS). Background Whether FKBI should be mandatory after simple stent implantation for the treatment of coronary bifurcation lesion is controversial. Besides, ACS patients who have undergone bifurcation percutaneous coronary intervention with simple stent implantation may experience worse prognosis compared to stable angina pectoris patients. Methods Two hundred and fifty one eligible patients (67.7% male, mean age 61.7 ± 10.4 years) were enrolled. The study population was divided into two groups according to the performance of FKBI. The primary end points were major adverse cardiac event (MACE); target lesion revascularization (TLR), non-fatal myocardial infarction (MI) and cardiac death during the follow-up period. Results Over a mean follow-up period of 3.0 ± 1.9 years, there were 29 MACEs (10 TLR, 6 non-fatal MI, and 13 cardiac deaths), representing an event rate of 11.6%. Kaplan–Meier survival analysis revealed that FBKI group had favorable outcome compared to non-FKBI group with regard to hard events (p = 0.010) as well as composite MACEs (p = 0.008). In multivariable analysis, FKBI was a significant predictor of composite MACEs [hazard ratio 0.398 (95% confidence interval 0.190–0.836, p = 0.015)] and hard events [hazard ratio 0.325 (95% confidence interval 0.130–0.811, p = 0.016)]. Conclusions In terms of prognosis, performing FKBI after simple stent implantation for the treatment of non-left main true coronary bifurcation lesions may be mandatory in ACS patients.
    International Journal of Cardiology. 01/2014;
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    ABSTRACT: A mixed layer of γ-Fe2O3 and Pt-Fe2O3 core-shell nanoparticles between Ti and Pt electrodes exhibited both analog and digital bipolar resistive switching depending on applied voltage. The resistance sequentially reduced with repeated −1.5 V sweeps and pulses for 100 ms and increased as repeating +1.5 V. After forming at +3 V, digital bipolar switching was achieved with SET transition from high to low resistance at +1 to 2 V and reverse RESET transition at −1 V. Pulse operation at ±2 V led to identical bipolar switching, associated with facilitated interconnection of filament segments between Pt cores in nanoparticle layer.
    Applied Physics Letters 01/2014; 104(9):093514-093514-5. · 3.52 Impact Factor
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    ABSTRACT: Several reports have suggested that thyrotoxicosis may induce severe coronary artery spasm (CAS). However, there are few data regarding the differences in clinical characteristics of CAS with and without thyrotoxicosis. The aim of our study is to compare the clinical features of CAS with and without thyrotoxicosis. We evaluated 430 consecutive patients with CAS [patients with thyrotoxicosis (N=32, group I) and those without (N=398, group II)] at a single institute between January 2001 and June 2011. We compared clinical presentations, angiographic findings, and adverse outcomes (a composite outcome of cardiac death, myocardial infarction, or rehospitalization due to cardiac cause) of both groups. There was higher incidence of acute myocardial infarction at initial presentation in group I (15.6 vs. 5.8%, P=0.04). CAS with thyrotoxicosis was more diffuse (59.4 vs. 39.3%, P=0.03), more medically intractable (9.4 vs. 0%, P=0.001), and more frequently involved the left main vessel (25.0 vs.0.8%, P=0.001) than CAS without thyrotoxicosis. During the follow-up period (median 43 months), there were no significant differences between the two groups in terms of the risk of adverse outcomes (hazard ratio for CAS with thyrotoxicosis, 1.029; 95% confidence interval, 0.347-3.054). Clinical and angiographic presentations of CAS with thyrotoxicosis were more severe than CAS without thyrotoxicosis, but clinical outcomes were similar in both groups. Optimal vasodilator therapy is essential for the management of CAS with thyrotoxicosis. Thyroid function test should be mandatory for all patients with CAS.
    Coronary artery disease 12/2013; · 1.56 Impact Factor
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    ABSTRACT: Periodically distributed ZnO nanostructure arrays were hydrothermally grown on silicon substrates. For the preferential, site-selective growth of the ZnO nanostructures, a seed layer was patterned using self-assembled monolayers of polystyrene spheres (PSs) lithography technique. The size of the seed layer was controlled by the size of PSs, which was determined by oxygen plasma etching time. Due to the existence of numerous nucleation sites, flower-like (FL) ZnO nanostructures grew on the large seed layer over 800 nm in diameter. By reducing the size of the seed layer, we could make a couple of ZnO nanowires grow on a single seed layer island. We examined the cathodoluminescence (CL) spectra of FL ZnO nanostructure arrays and coupled (CO) ZnO nanowire arrays. Since the dimension of the nanostructures is smaller than or comparable to the penetration depth of the incident electron, CL signal would be generated in the whole body of the nanostructures. So, the CL intensity might be proportional to the surface area through which the photons could escape. As a result, it is natural that the CL intensity from the FL ZnO nanostructure arrays should be stronger than that from the CO ZnO nanowire arrays. However, in spite of the smaller surface area, the CL intensity was strikingly enhanced in the CO ZnO nanowire arrays compared with the closely-packed ZnO nanowire arrays. It could be attributed to the suppression of the near-band-edge ultraviolet emission in the [0001] direction, which was observed in the monochromatic CL measurement.
    Journal of Nanoscience and Nanotechnology 12/2013; 13(12):8074-8. · 1.15 Impact Factor
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    ABSTRACT: We report a systematic and reliable approach to fabricate ZnO nanocone or nanoneedle arrays on various substrates including fibers. Our approach employs wet chemical etching of ZnO nanowire arrays using an aqueous solution of HCl. Using this simple chemical etching technique, nanowire arrays were transformed to nanocone arrays on Si substrates and Kevlar fibers. Significant enhancement of light emission intensities at UV peak (∼387 nm) was observed when the ZnO nanowire arrays are converted to ZnO nanocone arrays. The photoluminescence intensities at the UV peaks from the nanocones are found to be ∼3–4 times larger than those from the nanowires.
    Physica Status Solidi (A) Applications and Materials 12/2013; 210(12). · 1.53 Impact Factor
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    ABSTRACT: Ginseng and ginsenosides are frequently used in the treatment of chronic inflammatory diseases. Recently, 20-O-β-D-glucopyranosyl-20(S)-protopanaxadiol (GPD), the main metabolite of ginsenosides, was reported to have both anti-allergic and anti-pruritic effects. The immunomodulatory effects of GPD-fortified ginseng extract (GFGE) on atopic dermatitis (AD)-like symptoms in mice were investigated. This study was designed to investigate the preventive effect of GFGE on AD-like symptoms. The effects of orally administered GFGE on Dermatophagoides farinae body extract (DFE)-induced AD-like symptoms in NC/Nga mice were assessed by analyzing dermatitis score, ear thickness, scratching time, skin histological changes, and serum level of macrophage-derived chemokine (MDC). In addition, splenocytes were isolated from the mice and stimulated with anti-CD3 and anti-CD28 monoclonal antibodies to produce cytokines. Oral administration of GFGE significantly attenuated DFE-induced increases in dermatitis score, ear thickness, scratching time, and severity of skin lesions in NC/Nga mice. GFGE treatment also reduced level of MDC in serum, infiltration of eosinophils and mast cells in skin, and production of cytokines in splenocytes. These results suggest that GFGE might ameliorate DFE-induced AD-like symptoms and be an alternative therapeutic agent for the prevention of AD.
    Journal of ethnopharmacology 11/2013; · 2.32 Impact Factor

Publication Stats

708 Citations
302.05 Total Impact Points


  • 2014
    • MEDIPOST Biomedical Research Institute
      Sŏul, Seoul, South Korea
    • Sejong General Hospital
      Bucheon, Gyeonggi Province, South Korea
  • 2008–2014
    • Pusan National University
      • Department of Internal Medicine
      Tsau-liang-hai, Busan, South Korea
    • Purdue University
      West Lafayette, Indiana, United States
    • Chonbuk National University
      • Semiconductor Physics Research Center
      Sŏul, Seoul, South Korea
    • Hallym University
      Sŏul, Seoul, South Korea
    • Catholic University of Korea
      • College of Medicine
      Seoul, Seoul, South Korea
    • University of Cambridge
      • Department of Engineering
      Cambridge, England, United Kingdom
  • 2006–2014
    • Myongji University
      • • Department of Physics
      • • Department of Material Science and Engineering
      Sŏul, Seoul, South Korea
  • 1997–2014
    • Seoul National University
      • • College of Agriculture and Life Sciences
      • • Department of Agricultural Biotechnology
      • • Department of Electrical and Computer Engineering
      Sŏul, Seoul, South Korea
  • 2007–2013
    • Hallym University Medical Center
      • Department of Internal Medicine
      Seoul, Seoul, South Korea
    • Washington State University
      • School of Mechanical and Materials Engineering
      Pullman, Washington, United States
  • 2011
    • Gyeongsang National University
      • School of Materials Science and Engineering
      Chinju, South Gyeongsang, South Korea
  • 2009–2011
    • Chungbuk National University
      • College of Veterinary Medicine
      Tyundyu, North Chungcheong, South Korea
    • Sogang University
      • Department of Chemical and Biomolecular Engineering
      Seoul, Seoul, South Korea
    • Georgia Institute of Technology
      • School of Materials Science and Engineering
      Atlanta, GA, United States
  • 2010
    • Gangneung-Wonju National University
      • Department of Marine Molecular Biotechnology
      Kang-neung, Gangwon, South Korea
    • University of Science and Technology, Beijing
      Peping, Beijing, China
  • 2006–2008
    • Sungkyunkwan University
      • Department of Surgery
      Sŏul, Seoul, South Korea
  • 2005–2006
    • University of California, Davis
      • Department of Food Science and Technology
      Davis, California, United States
  • 2004
    • Korea Institute of Science and Technology
      • Interaction and Robotics Research Center
      Seoul, Seoul, South Korea
  • 1998–2000
    • Kyung Hee University
      • Department of Physics
      Seoul, Seoul, South Korea