Publications by authors named "Hyung-Kyu Yoon"

Background: Blood eosinophil count may predict treatment response in patients with chronic obstructive pulmonary disease (COPD) during acute exacerbations (AE). However, the ability and thresholds of blood eosinophil counts in stable status to predict eosinophilic AECOPD have not been completely investigated.

Methods: This was a retrospective multicenter study performed January 2010 to December 2014.

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Purpose: We compared the clinical characteristics and treatment outcomes of patients with eosinophilic and neutrophilic COPD exacerbations requiring hospital admission.

Patients And Methods: This was a retrospective multicenter study performed between January 2010 and December 2014. In all, 1,688 COPD patients admitted via the outpatient clinics or emergency departments of six university hospitals were enrolled.

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Lemierre syndrome (LS) is a septic thrombophlebitis of the internal jugular vein (IJV) following an oropharyngeal infection. LS is commonly caused by normal anaerobic flora and treated with appropriate antibiotics and anticoagulation therapy. Although the incidence of disease is very rare, 15% cases of LS are fatal even in the antibiotic era because of disseminated septic thromboemboli.

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Objectives: Expression of insulin-like growth factor 1 receptor (IGF-1R) in non-small cell lung cancer (NSCLC) is associated with poor prognosis. The IGF-1R pathway activates downstream targets that bypass dependency in signals from the epidermal growth factor receptor (EGFR), which mediates resistance to EGFR tyrosine kinase inhibitors (TKIs). The aim of the present study was to determine the predictive role of IGF-1R expression in the response to EGFR-TKIs of NSCLC patients harboring activating EGFR mutations.

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Lower respiratory tract infection is one of the most common infectious diseases. However, conventional methods for detecting infectious pathogens are time-consuming, and generally have a limited impact on early therapeutic decisions. We previously reported a rapid and sensitive method for detecting such pathogens using stuffer-free multiplex ligation-dependent probe amplification coupled with high-resolution CE-SSCP.

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Thrombin activates protease-activated receptor (PAR)-1 and induces a myofibroblast phenotype in normal lung fibroblasts. The origins of myofibroblasts are resident fibroblasts, fibrocytes, and epithelial-mesenchymal transition (EMT). We investigated the effects of thrombin, an important mediator of interstitial lung fibrosis, on EMT in A549 human alveolar epithelial cells.

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Purpose: Belotecan is a new camptothecin analogue and a potent topoisomerase I inhibitor. The aim of this phase II study was to investigate the efficacy and toxicity of belotecan in previously untreated elderly patients with small cell lung cancer (SCLC).

Methods: A total of 26 patients, aged ≥65 years, with previously untreated, extensive-stage SCLC were enrolled in the study.

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Background: Recent evidence suggests that acetylcholine acting through muscarinic receptors may play an inhibitory role in the mechanisms that drive the structural changes in the airways called airway remodeling. The novel anticholinergic drug tiotropium bromide, which selectively antagonizes muscarinic receptors, especially the M3 subtype, and is long acting, could be beneficial in attenuating airway remodeling in chronic asthma.

Objective: To investigate the effect of tiotropium bromide on parameters of airway remodeling, including smooth muscle hypertrophy and peribronchial thickening, in a mouse model of chronic asthma.

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Idiopathic pulmonary fibrosis (IPF) is a lethal parenchymal lung disease characterized by myofibroblast proliferation. Alveolar epithelial cells (AECs) are thought to produce myofibroblasts through the epithelial to mesenchymal transition (EMT). Receptor for advanced glycation end products (RAGE) is a member of the immunoglobulin superfamily of cell surface receptors whose activation is associated with renal fibrosis during diabetes and liver fibrosis.

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Background: The tyrosine kinase inhibitor imatinib mesylate was developed as an inhibitor of the kinase activity of BCR-ABL. However, imatinib also has potent inhibitory activity against the platelet-derived growth factor receptor (PDGFR). Nilotinib is approved for treating patients with chronic myeloid leukemia showing resistance or intolerance to imatinib.

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1. Pravastatin is best known for its antilipidemic action. Recent studies have shown that statins have immunomodulatory and anti-inflammatory effects.

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CXC chemokine receptor 4 (CXCR4), which binds the stromal cell-derived factor-1 (SDF-1), has been shown to play a critical role in mobilizing the bone marrow (BM)-derived stem cells and inflammatory cells. We studied the effects of AMD3100, CXCR4 antagonist, on a murine bleomycin-induced pulmonary fibrosis model. Treatment of mice with AMD3100 in bleomycin-treated mice resulted in the decrease of SDF-1 in bronchoalveolar lavage (BAL) fluids at an early stage and was followed by the decrease of fibrocytes in the lung.

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Alveolar epithelial cell injury and apoptosis is consistent findings in human idiopathic pulmonary fibrosis (IPF). Epithelial cell apoptosis is known to be induced by leukocyte elastase in vitro. The authors hypothesized that synthetic neutrophil elastase inhibitor, sivelestat (ONO-5046), can inhibit the bleomycin-induced pulmonary fibrosis in rats by blocking the apoptotic pathways in epithelial cells.

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Introduction: Neutropenia recovery may be associated with deterioration in oxygenation and exacerbation of pre-existing pulmonary disease. However, risk factors for acute respiratory distress syndrome (ARDS) during neutropenia recovery in patients with hematologic malignancies have not been studied.

Methods: We studied critically ill patients with hematologic malignancies with the dual objectives of describing patients with ARDS during neutropenia recovery and identifying risk factors for ARDS during neutropenia recovery.

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Background: Nitric oxide (NO) is generally increased during inflammatory airway diseases. This increased NO stimulates the secretion of mucin from the goblet cell and submucosal glands but the mechanism is still unknown precisely. In this study, we investigated potential signaling pathways involving protein kinase C (PKC) and mitogen-activated protein kinase (MAPK) in the NO-induced MUC5AC mucin gene and protein expression in A549 cells.

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Background: Neutrophil elastase (NE) was found to increase the respiratory mucin gene, MUC5AC, although the molecular mechanisms of this process remain unknown. We attempted to determine the signal transduction pathway through which NE induces MUC5AC gene expression in bronchial epithelial cells.

Methods: A fragment of 1.

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