Publications by authors named "Sung H Chun"

Article Synopsis
  • The study explores the link between gut microbiota and rheumatoid arthritis (RA), aiming to identify specific microbial species associated with RA through serum analysis.
  • Researchers assessed antibody levels against various intestinal microbes in RA patients compared to healthy individuals, discovering significant differences in immune responses.
  • The findings indicate that certain microbes have therapeutic potential by reducing inflammation and restoring gut health, suggesting a possible new approach for RA treatment.
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Interstitial lung disease (ILD) involves persistent inflammation and fibrosis, leading to respiratory failure and even death. Adult tissue-derived mesenchymal stem cells (MSCs) show potential in ILD therapeutics but obtaining an adequate quantity of cells for drug application is difficult. Daewoong Pharmaceutical's MSCs (DW-MSCs) derived from embryonic stem cells sustain a high proliferative capacity following long-term culture and expansion.

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Systemic sclerosis (SSc) is an autoimmune disorder characterized by fibrosis of the skin and internal organs. Despite several studies on SSc treatments, effective treatments for SSc are still lacking. Since evidence suggests an association between intestinal microbiota and SSc, we focused on butyrate, which has beneficial effects in autoimmune diseases as a bacterial metabolite.

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Growth mechanism of chemically-driven RuO2 nanowires is explored and used to fabricate three-dimensional RuO2 branched Au-TiO2 nanowire electrodes for the photostable solar water oxidation. For the real time structural evolution during the nanowire growth, the amorphous RuO2 precursors (Ru(OH)3 · H2O) are heated at 180 (°)C, producing the RuO2 nanoparticles with the tetragonal crystallographic structure and Ru enriched amorphous phases, observed through the in-situ synchrotron x-ray diffraction and the high-resolution transmission electron microscope images. Growth then proceeds by Ru diffusion to the nanoparticles, followed by the diffusion to the growing surface of the nanowire in oxygen ambient, supported by the nucleation theory.

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We found that resveratrol enhances interferon (IFN)-γ-induced tryptophanyl-tRNA-synthetase (TTS) expression in bone marrow- derived dendritic cells (BMDCs). Resveratrol-induced TTS expression is associated with glycogen synthase kinase-3β (GSK-3β) activity. In addition, we found that resveratrol regulates naïve CD8+ T-cell polarization by modulating GSK-3β activity in IFN-γ-stimulated BMDCs, and that resveratol induces upregulation of TTS in CD8+ T-cells in the in vivo tumor environment.

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Highly efficient single crystalline ruthenium-vanadium mixed metal oxide (Ru1-xVxO2, 0≤x≤1) nanowires were prepared on a SiO2 substrate and a commercial Au microelectrode for the first time through a vapor-phase transport process by adjusting the mixing ratios of RuO2 and VO2 precursors. Single crystalline Ru1-xVxO2 nanowires show homogeneous solid-solution characteristics as well as the distinct feature of having remarkably narrow dimensional distributions. The electrochemical observations of a Ru1-xVxO2 (x=0.

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This study showed the potential of resveratrol to inhibit the expression and activity of interferon-γ (IFN-γ)-induced indoleamine 2,3-dioxygenase (IDO) in bone marrow-derived dendritic cells (BMDCs). The mechanism of suppression was associated with the activity of Janus kinase/signal transducers and activators of transcription (JAK/STAT) and protein kinase Cδ (PKCδ). In addition, resveratrol-mediated IDO suppression in IFN-γ-stimulated BMDCs appears to play a pivotal role in anti-tumor activity through the regulation of CD8(+) T cell polarization and cytotoxic T lymphocyte (CTL) activity.

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Cancer stem cells (CSCs) are one of the main reasons behind cancer recurrence due to their resistance to conventional anti-cancer therapies. Thus, many efforts are being devoted to developing CSC-targeted therapies to overcome the resistance of CSCs to conventional anti-cancer therapies and decrease cancer recurrence. Differentiation therapy is one potential approach to achieve CSC-targeted therapies.

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Low dose radiation has been shown to be beneficial to living organisms using several biological systems, including immune and hematopoietic systems. Chronic low dose radiation was shown to stimulate immune systems, resulting in controlling the proliferation of cancer cells, maintain immune balance and induce hematopoietic hormesis. Since dendritic cells are differentiated from bone marrow cells and are key players in maintaining the balance between immune activation and tolerance, it may be important to further characterize whether low dose radiation can influence the capacity of bone marrow cells to differentiate into dendritic cells.

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Background: Typhoid, which is caused by Salmonella enterica serovar Typhimurium, remains a major health concern worldwide. Multidrug-resistant strains of Salmonella have emerged which exhibit increased survivability and virulence, thus leading to increased morbidity. However, little is known about the protective immune response against this microorganism.

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Heme oxygenase (HO)-1 is expressed in a variety of conditions involved in the regulation of immune responses. In this study, we examined the role of HO-1 in dendritic cell (DC) maturation and expression of indoleamine 2,3-dioxygenase (IDO), a key enzyme that catalyzes the initial, rate-limiting step in tryptophan degradation. IDO deficiency led to diminished phenotypic and functional maturation of DCs in vitro and in vivo.

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Indoleamine 2,3-dioxygenase (IDO), a key enzyme that catalyzes the initial, rate-limiting step in tryptophan degradation, is expressed in dendritic cells (DCs) which are stimulated by lipopolysaccharide (LPS) or interferons. In this study we show that curcumin inhibits IDO expression in vitro and in vivo in DCs, leading to the suppression of LPS-induced DC maturation. The effect of curcumin relative to LPS is not limited to the above, as it also enhances LPS-induced expression of cyclooxygenase (COX)-2 and production of prostaglandin E2 (PGE2).

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Oncostatin M (OSM) is a pleiotropic cytokine and a member of the gp130/IL-6 cytokine family that has been found to be involved in both pro- and anti-inflammatory responses in cell-mediated immunity. Maturation of dendritic cells (DCs) is crucial for initiation of primary immune responses and is regulated by several stimuli. In this study, the role of OSM in the phenotypic and functional maturation of DCs was evaluated in vitro.

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Background: Platelet-activating factor (PAF) has been long believed to be associated with many pathophysiological processes during septic shock. Here we present novel activities for PAF in protecting mice against LPS-mediated endotoxic shock.

Principal Findings: In vivo PAF treatment immediately after LPS challenge markedly improved the survival rate against mortality from endotoxic shock.

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Indoleamine 2,3-dioxygenase (IDO) catalyzes the initial and rate-limiting step in the degradation of tryptophan and is strongly induced in interferon-gamma (IFNgamma)-stimulated dendritic cells (DCs). IDO has recently been established as a key enzyme in T-cell suppression-mediated immune tolerance to tumors. STAT1 phosphorylation appears to play an important role in the control of IDO expression by IFNgamma, but the precise regulatory mechanism remains obscure.

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Background: Sudden cardiac death (SCD) has been shown to be a significant cause of death after heart transplantation. QT dispersion (QTd) is associated with SCD in several high-risk populations. We hypothesized that QTd would predict mortality and SCD in heart transplantation patients.

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Elevated intraocular pressure (IOP) is one of the major risk factors for glaucomatous visual field defects. Each individual systemic risk factor of coronary heart disease (CHD) is associated with elevated IOP, although no reports have argued for a correlation between the risk factors for CHD and IOP after a comprehensive or collective analysis. The National Cholesterol Education Program Adult Treatment Panel III presented the Framingham projection, which can predict the risk of CHD quantitatively.

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Right bundle branch block (RBBB) is the most common electrocardiographic abnormality in heart transplant recipients, but the cause remains unknown, data regarding the prognosis are conflicting, and all previous studies have been limited to <100 patients. This was a study of patients who underwent heart transplantation at Stanford University Medical Center from 1981 to 1995 with known outcomes and >or=2 available electrocardiograms (ECGs). Outcomes were assessed in those with and without conduction disturbances recorded from the ECGs closest to the time of transplantation and the most recent ECGs.

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A therapy-related myelodysplastic syndrome (t-MDS) during the course of Waldenström's macroglobulinemia (WM) has been observed in rare patients. In most of them, the condition developed after treatment with alkylating agents. We experienced a 65-year-old male patient who was diagnosed as WM.

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Background: Although many treatments for advanced gastric cancer have been developed, only poor treatment results have generally been obtained. We performed a prospective study on the combination chemotherapy of paclitaxel and cisplatin (PC). The primary objectives of the study were elucidating the disease response and evaluating the drug regimen's safety.

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We examined the prognostic value of computerized measurements of QT dispersion in 37,579 male veterans. The results of our study showed that QT dispersion is a poor independent predictor of cardiovascular mortality.

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Purpose: To determine whether retinal electrophysiologic changes can be detected and correlated with funduscopic findings in patients with the long-term use of amiodarone.

Methods: Eleven patients ranging in age from 52 to 67 years were recruited from the Stanford University Medical Center Department of Cardiology for ophthalmologic examination. Patients had received amiodarone at various dosages ranging from 100 to 800 mg daily for at least 15 months.

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