Dae Hun Kim

Catholic University of Korea, Sŏul, Seoul, South Korea

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Publications (24)54.65 Total impact

  • Dae Hun Kim, Tae Whan Kim
    Organic Electronics 12/2014; 15(12):3452–3457. · 3.84 Impact Factor
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    ABSTRACT: Raloxifene is widely used for the treatment and prevention of postmenopausal osteoporosis. We examined the effects of raloxifene on the Kv4.3 currents expressed in Chinese hamster ovary (CHO) cells using the whole-cell patch-clamp technique and on the long-term modulation of Kv4.3 messenger RNA (mRNA) by real-time PCR analysis. Raloxifene decreased the Kv4.3 currents with an IC50 of 2.0 μM and accelerated the inactivation and activation kinetics in a concentration-dependent manner. The inhibitory effects of raloxifene on Kv4.3 were time-dependent: the association and dissociation rate constants for raloxifene were 9.5 μM(-1) s(-1) and 23.0 s(-1), respectively. The inhibition by raloxifene was voltage-dependent (δ = 0.13). Raloxifene shifted the steady-state inactivation curves in a hyperpolarizing direction and accelerated the closed-state inactivation of Kv4.3. Raloxifene slowed the time course of recovery from inactivation, thus producing a use-dependent inhibition of Kv4.3. β-Estradiol and tamoxifen had little effect on Kv4.3. A preincubation of ICI 182,780, an estrogen receptor antagonist, for 1 h had no effect on the inhibitory effect of raloxifene on Kv4.3. The metabolites of raloxifene, raloxifene-4'-glucuronide and raloxifene-6'-glucuronide, had little or no effect on Kv4.3. Coexpression of KChIP2 subunits did not alter the drug potency and steady-state inactivation of Kv4.3 channels. Long-term exposure to raloxifene (24 h) significantly decreased the expression level of Kv4.3 mRNA. This effect was not abolished by the coincubation with ICI 182,780. Raloxifene inhibited Kv4.3 channels by interacting with their open state during depolarization and with the closed state at subthreshold potentials. This effect was not mediated via an estrogen receptor.
    Pflugers Archiv : European journal of physiology. 09/2014;
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    ABSTRACT: X-box binding protein 1 (XBP1), a transcription factor of the unfolded protein response, plays various roles in many biological processes. We examined the pro-adipogenic activity and its target genes during adipogenic differentiation in wild type and genetically-modified 3T3-L1 cells. Signalling pathways that contribute to Xbp1 mRNA splicing and the correlation of transcriptionally active XBP1 isoform (XBP1s) level with body mass index and PPARγ2 in human adipose tissues were also examined. The mRNA and nuclear protein expression levels of XBP1s increased immediately, reaching a peak at 6 h, following hormonal induction of adipogenesis. Results from cDNA microarray and gene expression analyses using genetically modified cells indicated that PPARγ2 was a principal target of XBP1s. The XBP1s-specific binding motif, which is distinct from the CCAAT/enhancer-binding protein α-binding site, was identified in the PPARγ2 promoter by site-directed mutagenesis. Foetal bovine serum, insulin, 3-isobutyl-1-methylxanthine, and dexamethasone contributed independently to Xbp1 mRNA splicing. In human subcutaneous adipose tissues, both Xbp1s and Pparγ2 mRNA levels increased proportionally with body mass index and there was a significant positive correlation between the two genes. These data suggest for the first time that the positive regulation of PPARγ2 is a principal mechanism of XBP1s-mediated adipogenesis in 3T3-L1 cells.This article is protected by copyright. All rights reserved.
    FEBS Journal 09/2014; · 4.25 Impact Factor
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    ABSTRACT: While the operating voltage of the tandem organic light-emitting devices (OLEDs) with both an organic p-type 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile charge generation layer and a bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF)-doped 1,3,5-tris(N-phenylbenzimiazole-2-yl)benzene (TPBi) electron transport layer (ETL) was 1.3 V lower than that of the tandem OLEDs with a BEDT-TTF-undoped TPBi ETL. Luminance efficiency of the tandem OLEDs with a BEDT-TTF-doped TPBi ETL was 3.6 cd/A higher than that of the typical OLEDs. The increase in the luminance efficiency and the decrease in the operating voltage of the tandem OLEDs were attributed to improved electron injection due to the insertion of the BEDT-TTF-doped TPBi ETL.
    Thin Solid Films 01/2014; 570:63–67. · 1.87 Impact Factor
  • Ke Xu, Dae Hun Kim, Se Han Lee, Tae Whan Kim
    Thin Solid Films 11/2013; · 1.87 Impact Factor
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    ABSTRACT: In this surveillance study, we identified the genotypes, carbapenem resistance determinants, and structural variations of AbaR-type resistance islands among carbapenem-resistant Acinetobacter baumannii (CRAB) isolates from nine Asian locales. Clonal complex 92 (CC92), corresponding to global clone (GC) 2, was the most prevalent in most Asian locales (83/108 isolates, 76.9%). CC108 or GC1 was a predominant clone in India. OXA-23 oxacillinase was detected in CRAB isolates from most Asian locales except Taiwan. blaOXA-24 was found in CRAB isolates from Taiwan. AbaR4-type resistance islands, which were divided into six subtypes, were identified in most CRAB isolates investigated. Five isolates from India, Malaysia, Singapore, and Hong Kong contained AbaR3-type resistance islands. Of these, three isolates harbored both AbaR3- and AbaR4-type resistance islands simultaneously. In this study, GC2 was revealed as a prevalent clone in most Asian locales, with the AbaR4-type resistance island predominant with diverse variants. The significance of this study is to identify the spread of global clones of carbapenem-resistant A. baumannii in Asia.
    Antimicrobial Agents and Chemotherapy 08/2013; · 4.57 Impact Factor
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    ABSTRACT: Dynamic characteristics about motion of Taylor vortex flow and separation of particles in Taylor–Couette reactor were investigated numerically and experimentally. Commercial computational fluid dynamics (CFD) program was used for calculation of the fluid dynamics of Taylor vortex flow and particle classification system. Gravitational and drag force balance affect the particles, when the Taylor–Couette reactor is vertically located. Thus, the particles movement depends on the size of particles and reactor operating conditions. When rotational speed of inner cylinder increases or the feed flow rate decreases, the axial moving velocity of the Taylor vortex decreases. In this study, the Taylor vortex moving velocity and moving region were determined for the various rotational speeds of the inner cylinder and inlet flow rates. To investigate the performance of particle classification, particles with various sizes injected at the center of reactor by Particle-tracking simulations. Then, the Taylor–Couette reactor applied as a crystallizer was proposed, which simultaneously classify the crystals.
    Journal of Crystal Growth 06/2013; 373:106–110. · 1.55 Impact Factor
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    ABSTRACT: Trastuzumab (Herceptin), a humanized monoclonal antibody, is a cancer drug developed to target the human epidermal receptor (HER) 2, which is overexpressed in some cancer cells. Cutaneous side effects, such as folliculitis, xerosis, and alopecia have not been reported with therapies targeting HER2, in spite of the frequent observances of such with the therapies targeting the epidermal growth factor receptor. We experienced a patient in whom psoriasis was triggered by the trastuzumab treatment for breast cancer. She was a 57-year-old woman with erythematous and scaly plaques occurring a few months after starting trastuzumab, with repeated aggravation after the re-administration of trastuzumab for the breast cancer. Histologic examination showed the typical features of psoriasis with parakeratosis, epidermal hyperplasia, elongation of the rete ridges, and a lymphocytic and polymorphonuclear cell infiltrate in the dermis. To the best of our knowledge, this is the first report of psoriasis triggered by trastuzumab treatment for breast cancer.
    Annals of Dermatology 05/2013; 25(2):229-231. · 0.61 Impact Factor
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    ABSTRACT: Differentiation of preadipocytes into adipocytes is controlled by various transcription factors. Recently, the pro-adipogenic function of XBP1, a transcription factor upregulated by endoplasmic reticulum stress, has been reported. In this study, we demonstrated that XBP1 suppresses the expression of Wnt10b, an anti-adipogenic Wnt, during the differentiation of 3T3-L1 preadipocytes. The expression pattern of XBP1 was reciprocal to that of Wnt10b during the early stage of adipogenesis. The intracellular protein levels of β-catenin were negatively regulated by XBP1. Direct binding of XBP1 to the Wnt10b promoter and the subsequent decrease of the β-catenin signalling pathway represent a novel adipogenic differentiation mechanism.
    FEBS letters 04/2013; · 3.54 Impact Factor
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    ABSTRACT: In organic photovoltaic (OPV) cells, the nanoscale morphology of the organic layer is an essential parameter governing their charge-transport properties. Optimization of the vertical composition gradient in the poly(3-hexylthiophene) (P3HT) active layer in an OPV cell with an enhanced efficiency was achieved by using different sonication times of 10, 15, 20, 25, and 30 min. Atomic force microscopy images confirmed that the sonication process increased the roughness of the P3HT layer in a vertically modulated nanoscale morphology. Photoluminescence spectra exhibited a strong peak corresponding to the P3HT particles. The power conversion efficiency of the OPV cells with a vertically modulated P3HT nanostructural layer sonicated at 15 min was enhanced by 1.04% due to an increase in the interfacial region between the acceptor and the donor materials.
    Applied Surface Science 03/2013; 268:156–162. · 2.54 Impact Factor
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    ABSTRACT: A 28-year-old Asian male was referred for dermatologic evaluation of diffuse bluish-red maculopapules in the lower trunk and genital regions. There was no family history, and with the exception of dispersed skin lesions and hypohidrosis, no other complaints or symptoms were present. Histological evaluation of the skin lesions revealed angiokeratomas. When this combination of clinical and histological findings is observed, Fabry disease is suspected. Biochemical examination performed for definitive diagnosis did not show any activity of the α-galactosidase A enzyme. Through identification of a c.182_183ins(GA) mutation of the GLA gene, Fabry disease was diagnosed. However, there was no particular abnormal finding with regard to the evaluation of non-cutaneous manifestations, a symptom that can occur in the progress of this disease. We reported a case of Fabry disease, restricted to the dermatologic presentation, involving a novel frameshift mutation in the GLA gene.
    Annals of Dermatology 02/2013; 25(1):95-8. · 0.61 Impact Factor
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    ABSTRACT: The efficiency of the organic light-emitting devices (OLEDs) was enhanced with increasing thickness of a 5,6,11,12-tetraphenylnaphthacene (rubrene) emission layer (EML). The charge trapping and the luminance mechanisms were affected by the thickness of the rubrene layer, regardless of the existence of the barrier layers. The variation in the electroluminescence spectra of devices originated from a variation in the position of the recombination region with increasing thickness of the EML. The enhancement of the luminescence efficiency for devices was attributed to the better charge balance and the optimized recombination region.
    Molecular Crystals and Liquid Crystals 01/2013; 583(1). · 0.53 Impact Factor
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    ABSTRACT: This study reports for the first time the AbaR4-type resistance island with the bla(OXA-23) gene in two carbapenem-resistant A. nosocomialis isolates from South Korea and Thailand.
    Antimicrobial Agents and Chemotherapy 06/2012; 56(8):4548-9. · 4.57 Impact Factor
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    ABSTRACT: AbaR resistance islands in Acinetobacter baumannii isolates from South Korea were investigated. AbaR4-type resistance islands, including bla(OXA-23)-containing Tn2006, interrupted the comM gene in A. baumannii ST75 isolates. However, Tn2006 was not identified within AbaR resistance islands of ST138 isolates, although the bla(OXA-23) gene was detected in them. The similar structures of resistance islands suggest that most carbapenem-resistant A. baumannii isolates in South Korea have originated from the same ancestor with a globally disseminated clone, GC II.
    Antimicrobial Agents and Chemotherapy 06/2012; 56(8):4544-7. · 4.57 Impact Factor
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    ABSTRACT: Organic photovoltaic (OPV) cells utilizing a rugged nanostructural layer were fabricated by using a mixed solution method. The charge separation at the heterointerface between the poly(3-hexylthiophene) (P3HT) nanostructural layer with a rugged surface and the C60 layer was increased due to an increase in the interfacial region between the donor and the acceptor layers, resulting in an increase in the short-circuit current density and the power conversion efficiency (PCE) of the OPV cells with a P3HT nanostructural layer. The PCE of the OPV cells with a nanostructural rugged layer is 30% higher than that without a rugged layer.
    Organic Electronics 06/2012; 13(6):1068–1072. · 3.84 Impact Factor
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    ABSTRACT: During multilocus sequence analysis of Acinetobacter calcoaceticus-Acinetobacter baumannii complex, we identified the evidence of recent genetic recombination between 2 Acinetobacter species. While 3 isolates belonged to A. nosocomialis based on 16S rRNA, gyrB, fusA, gdhB, and rplB gene sequences, they showed close relationships with Acinetobacter genomic species 'close to 13TU' in rpoB, recA, cpn60, rpoD, and gltA gene trees.
    Diagnostic microbiology and infectious disease 05/2012; 73(3):284-6. · 2.45 Impact Factor
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    ABSTRACT: High-efficiency organic photovoltaic (OPV) cells utilizing a poly(3-hexylthiophene) (P3HT) pillar layer containing ZnSe quantum dots (QDs) were fabricated by using a mixed solution method. Scanning electron microscopy and high-resolution transmission electron microscopy images showed that the ZnSe QDs were dispersed in the P3HT layer. The power conversion efficiency of the OPV cells with a P3HT pillar layer containing ZnSe QDs was as much as 100% higher than that of the OPV cells with a planar layer due to an enhancement of the photon-harvesting ability of the congregated P3HT particles containing ZnSe QDs and to an increase of the interfacial region for efficient charge transport.
    Optics Express 05/2012; 20(10):10476-83. · 3.55 Impact Factor
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    ABSTRACT: Imatinib mesylate (Gleevec™, STI571), a selective inhibitor of BCR-ABL, c-Kit, and platelet-derived factor receptor, has been used to treat chronic myelogenous leukemia (CML) and gastrointestinal stromal tumors. Although its use has been associated with various adverse cutaneous reactions, pityriasis rosea-like drug eruptions are rare. Here, we report a case of pityriasis rosea-like drug eruption that developed following the administration of imatinib mesylate to treat CML.
    Annals of Dermatology 12/2011; 23(Suppl 3):S360-3. · 0.61 Impact Factor
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    ABSTRACT: Autologous platelet-rich plasma has attracted attention in various medical fields recently, including orthopedic, plastic, and dental surgeries and dermatology for its wound healing ability. Further, it has been used clinically in mesotherapy for skin rejuvenation. In this study, the effects of activated platelet-rich plasma (aPRP) and activated platelet-poor plasma (aPPP) have been investigated on the remodelling of the extracellular matrix, a process that requires activation of dermal fibroblasts, which is essential for rejuvenation of aged skin. Platelet-rich plasma (PRP) and platelet-poor plasma (PPP) were prepared using a double-spin method and then activated with thrombin and calcium chloride. The proliferative effects of aPRP and aPPP were measured by [(3)H]thymidine incorporation assay, and their effects on matrix protein synthesis were assessed by quantifying levels of procollagen type I carboxy-terminal peptide (PIP) by enzyme-linked immunosorbent assay (ELISA). The production of collagen and matrix metalloproteinases (MMP) was studied by Western blotting and reverse transcriptase-polymerase chain reaction. Platelet numbers in PRP increased to 9.4-fold over baseline values. aPRP and aPPP both stimulated cell proliferation, with peak proliferation occurring in cells grown in 5% aPRP. Levels of PIP were highest in cells grown in the presence of 5% aPRP. Additionally, aPRP and aPPP increased the expression of type I collagen, MMP-1 protein, and mRNA in human dermal fibroblasts. aPRP and aPPP promote tissue remodelling in aged skin and may be used as adjuvant treatment to lasers for skin rejuvenation in cosmetic dermatology.
    Annals of Dermatology 11/2011; 23(4):424-31. · 0.61 Impact Factor
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    ABSTRACT: Acinetobacter species have emerged as opportunistic nosocomial pathogens in intensive care units. Epidemic spread and outbreaks of multidrug-resistant or carbapenem-resistant Acinetobacter baumannii infections have been described worldwide. Species distribution, antimicrobial resistance and genotypes were investigated for Acinetobacter species isolates collected from a single institution in Korea over 7 years. Two hundred and eighty-seven Acinetobacter species isolates were collected from patients with bloodstream infections in one Korean hospital from 2003 to 2010. Most of them belonged to the Acinetobacter calcoaceticus-baumannii complex (94.4 %). The most frequently isolated species was A. baumannii (44.2 %), followed by Acinetobacter nosocomialis (formerly Acinetobacter genomic species 13TU) (34.1 %). The proportion of A. baumannii increased significantly from 2008 to 2010 (40.4 to 50.0 %). From 2008, imipenem and meropenem resistance rates increased significantly compared with 2003-2007 (12.9 % and 20.5 %, respectively, to 41.4 % and 41.5 %, respectively). An increased carbapenem resistance rate between the two periods was identified more clearly amongst A. baumannii isolates. Polymyxin-resistant A. baumannii isolates emerged in 2008-2010, despite the availability of few isolates. The increase of carbapenem resistance in A. baumannii might be due to the substitution of main clones. Although ST92 and ST69 were the most prevalent clones amongst A. baumannii in 2003-2007 (47.8 % and 15.9 %, respectively), ST75 and ST138 had increased in 2008-2010 (39.7 % and 25.9 %, respectively). Although ST92 showed moderate resistance to carbapenems, most ST75 and ST138 isolates were resistant to carbapenems. All ST75 and ST138 isolates, but only one ST92 isolate, contained the bla(OXA-23-like) gene. Increased carbapenem resistance in Acinetobacter species and A. baumannii isolates might be due to the expansion of specific carbapenem-resistant clones.
    Journal of Medical Microbiology 08/2011; 61(Pt 1):71-9. · 2.30 Impact Factor

Publication Stats

62 Citations
54.65 Total Impact Points

Institutions

  • 2014
    • Catholic University of Korea
      Sŏul, Seoul, South Korea
  • 2012–2013
    • Hanyang University
      • Department of Electronics and Computer Engineering
      Seoul, Seoul, South Korea
    • Chonnam National University
      • Department of Infectious Diseases
      Gwangju, Gwangju, South Korea
  • 2011–2013
    • Sungkyunkwan University
      • Department of Molecular and Cell Biology
      Sŏul, Seoul, South Korea
  • 2009–2013
    • Chungnam National University
      • Department of Dermatology
      Daiden, Daejeon, South Korea