S Y Park

Konyang University, Nonsan, South Chungcheong, South Korea

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Publications (8)21.53 Total impact

  • H Ko, S Y Park, E J Cha, J S Sohn
    Cytopathology 05/2013; · 1.71 Impact Factor
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    ABSTRACT: Background  Erythema induratum of Bazin (EIB) is regarded to be a hypersensitive reaction to the concomitant tuberculosis. Recently, interferon-γ releasing assay (IGRA) has been focused as a promising tool in the diagnosis of latent tuberculosis. However, there has been no large scale study to investigate the usefulness of IGRA in the diagnosis of EIB. Objectives  To evaluate the diagnostic performance for the detection of EIB. Methods  We retrospectively reviewed medical records of all patients with EIB, in the Department of Dermatology, at the Seoul National University Hospital, between April 2009 and September 2011. We analysed clinicopathological features, responses to IGRA and the treatment courses. In addition, we compared positive rate of IGRA in patients with other diseases during the same period. Results  All of the 22 patients demonstrated a positive response to IGRA (100%) and showed a good response to anti-tuberculosis treatment. In contrast, positive rate was 63.64% and 66.67% in patients with psoriasis and other vasculitis respectively. We observed complete resolution of skin lesions in 14 patients. Partial resolution was attained in one patient and the other seven patients are currently on the medication and are showing good responses. Conclusion  We verified that IGRA has an excellent diagnostic performance in EIB, through this observational study. It is strongly suggested that if EIB is clinicopathologically suspected, IGRA should be performed.
    Journal of the European Academy of Dermatology and Venereology 12/2012; · 2.69 Impact Factor
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    ABSTRACT: Lysophosphatidic acid (LPA) is a biolipid that has diverse biological activities implicated in ovarian cancer initiation and progression. Previous studies have shown the critical role of the Rho/Rho-associated kinase (ROCK) pathway in LPA-induced ovarian cancer progression. However, detailed underlying mechanism by which the Rho/ROCK pathway induces ovarian cancer cell invasion is still incompletely understood. In the present study, we observed that the Rho/ROCK pathway is implicated in the production of proteolytic enzymes, leading to LPA-induced ovarian cancer cell invasion. LPA induced matrix metalloproteinase (MMP)-9 expression in CAOV-3 and PA-1 cells and urokinase-type plasminogen activator (uPA) expression in SKOV-3 cells. LPA-induced proteolytic enzyme expression was required for the invasion of ovarian cancer cells expressing corresponding enzymes. Pretreatment of cells with a pharmacological inhibitor of Rho/ROCK (Y-27632) or overexpression of a dominant-negative mutant of Rho (Rho N19) profoundly inhibited LPA-induced proteolytic enzyme expression as well as the invasive potential of ovarian cancer cells. In addition, transfection with dominant-negative Ras (Ras N17) significantly inhibited LPA-induced Rho activation as well as MMP-9 and uPA expression. Consistently, Y-27632 reduced LPA-induced nuclear factor (NF)-κB activation that is critical for proteolytic enzyme expression and cellular invasion. Collectively, we demonstrate a mechanism by which LPA promotes ovarian cancer progression through coordinate activation of a Ras/Rho/ROCK/NF-κB signaling pathway and the proteolytic enzyme secretion, providing novel biomarkers and promising therapeutic targets for ovarian cancer cell progression.
    Oncogene 01/2012; 31(39):4279-89. · 8.56 Impact Factor
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    ABSTRACT: Lysophosphatidic acid (LPA), produced extracellularly by autotaxin (ATX), has diverse biological activities implicated in tumor initiation and progression, including increasing cell survival, angiogenesis, invasion and metastasis. ATX, LPA and the matrix metalloproteinase (MMP)-9 have all been implicated in hepatocellular carcinoma (HCC) invasion and metastasis. We, thus sought to determine whether ATX with subsequent LPA production and action, including induction of MMP-9 could provide a unifying mechanism. ATX transcripts and LPA receptor type 1 (LPA1) protein are elevated in HCC compared with normal tissues. Silencing or pharmacological inhibition of LPA1 significantly attenuated LPA-induced MMP-9 expression and HCC cell invasion. Further, reducing MMP-9 activity or expression significantly inhibits LPA-induced HCC cell invasion, demonstrating that MMP-9 is downstream of LPA1. Inhibition of phosphoinositide-3 kinase (PI3K) signaling or dominant-negative mutants of protein kinase Cδ and p38 mitogen-activated protein kinase (MAPK) abrogated LPA-induced MMP-9 expression and subsequent invasion. We thus demonstrate a mechanistic cascade of ATX-producing LPA with LPA activating LPA1 and inducing MMP-9 through coordinate activation of the PI3K and the p38 MPAK signaling cascades, providing novel biomarkers and potential therapeutic targets for HCC.
    Oncogene 11/2010; 30(11):1351-9. · 8.56 Impact Factor
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    ABSTRACT: In the present investigation, the microstructure of nano tungsten carbide/cobalt (WC/Co) coating layers fabricated by detonation-gun spraying has been studied. Phase identification and three-dimensional distribution of constituent elements have been accomplished by using an ultra high-resolution transmission electron microscope (TEM) and a three-dimensional atom probe tomography (3D-APT), respectively. The microstructures of WC/Co coating layer containing superfine carbides were observed in various forms, i.e., unmelted, partially melted and fully melted regions. TEM and APT results revealed that the WC phase has been decomposed into crystalline W2C, W and complex amorphous phases during high temperature detonation spraying and rapid quenching process.
    Surface & Coatings Technology - SURF COAT TECH. 01/2010; 205(2):430-435.
  • S.Y. Park, M.C. Kim, C.G. Park
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    ABSTRACT: Effects of post heat treatment of thermally sprayed nano WC–Co coatings on their mechanical properties were studied. The thermal behavior of WC particles in the coatings was also investigated. WC–Co coatings containing nano carbide particles in the 100–200 nm range were fabricated by detonation gun spraying. Considerable phase decomposition of WC to W2C and amorphous phase was detected, which degrades the mechanical properties of coatings. In order to improve the mechanical properties of the coatings by recovery of dissociated carbide phases, post heat treatment was conducted in an Ar environment in the temperature range of 400–900 °C. Microhardness and fracture toughness were measured by Vickers indentation testing and wear resistance was also evaluated by using a scratch tester. Phase evolution and microstructural changes due to post heat treatment were investigated by optical microscopy, X-ray diffractometry and field-emission scanning electron microscopy. After heat treatment in all temperature ranges, microhardness increased. Fracture toughness and wear resistance of coatings were increased by increasing temperature to 800 °C but decreased after heat treatment at 900 °C. Amorphous phase disappeared and other carbide phases such as W3Co3C and W6Co6C formed during heat treatment above 700 °C. The improved properties were elucidated and discussed in terms of microstructural changes and the relationship between mechanical properties and carbide phase was also discussed.
    Materials Science and Engineering: A. 01/2007;
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    ABSTRACT: The effects of Si addition on microstructure and magnetic properties of permalloy strips fabricated by the melt drag casting method were investigated. Permalloy strips with 200 mm width were successfully fabricated by melt drag casting followed by homogenizing, cold rolling and annealing. In order to understand the relationship between microstructure and magnetic properties, we measured permeability and analyzed microstructure as a function of Si content by optical microscopy, X-ray diffraction and transmission electron microscopy. The effective permeability went through a maximum value in 2 at.% Si added permalloy strips and then decreased with increasing Si content. Increasing Si content enlarged grain size, which resulted in improvement of permeability. Permalloy strips with 5 at.% Si, however, showed drastically reduced permeability than that of 2 at.% Si added ones notwithstanding their coarse grain size and little oxide inclusion. The degradation of permeability in over-added Si above 2 at.% could be explained by formation of Ni3Fe ordered phase, which increase magneto-crystalline anisotropy.
    Materials Science and Engineering: A. 01/2007;
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    ABSTRACT: Permalloy strips with 200 mm width were successfully fabricated by melt drag casting, and their microstructure and consequent magnetic properties were analyzed as a function of Si content. The effective permeability went through a maximum value for 2% Si-containing permalloy strips and then decreased with increasing Si content. Increasing Si content enlarged grain size, which improved permeability. However, addition of Si above 2% caused the formation of Ni3Fe ordered phase, which drastically reduced permeability in 5% Si-added permalloy strips.
    Scripta Materialia. 01/2006; 54(4):621-625.

Publication Stats

60 Citations
21.53 Total Impact Points

Institutions

  • 2010
    • Konyang University
      • College of Medicine
      Nonsan, South Chungcheong, South Korea
  • 2006–2010
    • Pohang University of Science and Technology
      • Department of Materials Science and Engineering
      Antō, North Gyeongsang, South Korea