Publications by authors named "Soo Young Chung"

15 Publications

  • Page 1 of 1

The Conserved Cys-2232 in Toxin B Modulates Receptor Binding.

Front Microbiol 2018 26;9:2314. Epub 2018 Oct 26.

Institute of Toxicology, Hannover Medical School, Hanover, Germany.

toxins TcdA and TcdB are large clostridial glucosyltransferases which are the main pathogenicity factors in -associated diseases. Four highly conserved cysteines are present in all large clostridial glucosyltransferases. In this study we focused on the conserved cysteine 2232 within the combined repetitive oligopeptide domain of TcdB from reference strain VPI10463 (clade I). Cysteine 2232 is not present in TcdB from hypervirulent strain R20291 (clade II), where a tyrosine is found instead. Replacement of cysteine 2232 by tyrosine in TcdB reduced binding to the soluble fragments of the two known TcdB receptors, frizzled-2 (FZD2) and poliovirus receptor-like protein-3/nectin-3 (PVRL3). In line with this, TcdB showed weak binding to PVRL3 in pull-down assays which was increased when tyrosine 2232 was exchanged for cysteine. Surprisingly, we did not observe binding of TcdB to FZD2, indicating that this receptor is less important for this toxinotype. Competition assay with the receptor binding fragments (aa 1101-1836) of TcdB and TcdB, as well as antibodies newly developed by antibody phage display, revealed different characteristics of the yet poorly described delivery domain of TcdB harboring the second receptor binding region. In summary, we found that conserved Cys-2232 in TcdB indirectly contributes to toxin-receptor interaction.
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http://dx.doi.org/10.3389/fmicb.2018.02314DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6212469PMC
October 2018

Oncogenic role of SIRT1 associated with tumor invasion, lymph node metastasis, and poor disease-free survival in triple negative breast cancer.

Clin Exp Metastasis 2016 Feb 19;33(2):179-85. Epub 2015 Nov 19.

Department of Pathology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.

The aim of this study is to evaluate the biological role and clinical implications of silent mating type information regulation 2 homolog 1 (SIRT1) as a novel candidate for target therapy in triple negative breast cancer (TNBC) for which there is no specific agent. 344 patients who received surgical resection for TNBC from January 2003 to December 2006 at Seoul National University Hospital were enrolled, and the role of SIRT1 protein was evaluated via immunohistochemistry on tissue samples. In vivo experiments to evaluate tumor invasiveness were carried out with three human TNBC cell lines following SIRT1-siRNA transfection. Expression of SIRT1 significantly correlated with lymph node metastasis (p = 0.008). In multivariate analysis, SIRT1 expression (p = 0.011), T stage (p = 0.014), and lymphatic invasion (p < 0.001) were revealed to be independent predictive factors for lymph node metastasis. Combination of these three parameters revealed predictive performance for lymph node metastasis with an area under the curve (AUC) of 0.689 on receiver operating characteristics (ROC) curves analysis. SIRT1 expression correlated with shorter disease-free survival (P = 0.003) but not with overall survival. Inhibition of SIRT1 with small interfering RNA (siRNA) conspicuously suppressed the invasiveness of TNBC cell lines. This study reveals the role of SIRT1 on tumor invasiveness and unfavorable clinical outcomes, and we suggest its potential role as a prognostic indicator as well as a novel therapeutic target in TNBC.
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http://dx.doi.org/10.1007/s10585-015-9767-5DOI Listing
February 2016

The ameliorative effect of silibinin against radiation-induced lung injury: protection of normal tissue without decreasing therapeutic efficacy in lung cancer.

BMC Pulm Med 2015 Jul 5;15:68. Epub 2015 Jul 5.

Dongnam Institute of Radiological and Medical Sciences (DIRAMS), Busasn, South Korea.

Background: Silibinin has been known for its role in anti-cancer and radio-protective effect. Radiation therapy for treating lung cancer might lead to late-phase pulmonary inflammation and fibrosis. Thus, this study aimed to investigate the effects of silibinin in radiation-induced lung injury with a mouse model.

Methods: In this study, we examined the ability of silibinin to mitigate lung injury in, and improve survival of, C57BL/6 mice given 13 Gy thoracic irradiation and silibinin treatments orally at 100 mg/kg/day for seven days after irradiation. In addition, Lewis lung cancer (LLC) cells were injected intravenously in C57BL/6 mice to generate lung tumor nodules. Lung tumor-bearing mice were treated with lung radiation therapy at 13 Gy and with silibinin at a dose of 100 mg/day for seven days after irradiation.

Results: Silibinin was shown to increase mouse survival, to ameliorate radiation-induced hemorrhage, inflammation and fibrosis in lung tissue, to reduce the number of inflammatory cells in the bronchoalveolar lavage fluid (BALF) and to reduce inflammatory cell infiltration in the respiratory tract. In LLC tumor injected mice, lung tissue from mice treated with both radiation and silibinin showed no differences compared to lung tissue from mice treated with radiation alone.

Conclusions: Silibinin treatment mitigated the radiation-induced lung injury possibly by reducing inflammation and fibrosis, which might be related with the improved survival rate. Silibinin might be a useful agent for lung cancer patients as a non-toxic complementary approach to alleviate the side effects by thorax irradiation.
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http://dx.doi.org/10.1186/s12890-015-0055-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4499198PMC
July 2015

A Pilot Study Evaluating Fine-Needle Aspiration Cytology of Clear-Cell Renal Cell Carcinoma: Comparison of Ancillary Immunocytochemistry and Cytomorphological Characteristics of SurePath™ Liquid-Based Preparations with Conventional Smears.

Acta Cytol 2015 29;59(3):239-47. Epub 2015 May 29.

Department of Pathology, The Armed Forces Capital Hospital, Seongnam, South Korea.

Objective: Fine-needle aspiration cytology (FNAC) based on a liquid-based preparation is a safe and valuable diagnostic tool. However, due to unfamiliarity with this method and the considerably altered morphology that is associated with it, diagnosing renal cell carcinoma (RCC) from this type of preparation remains a challenge for cytopathologists. The aim of this study was to evaluate the cytomorphological characteristics of SurePath™ (SP)-based preparations compared with conventional smear (CS), and also the role of SP-based FNAC in the diagnosis of clear-cell RCC (CRCC), the most common primary renal malignancy.

Study Design: Ex vivo FNAC of both tumors and normal renal parenchyma was prepared from 73 cases. Comparative cytomorphological analysis between liquid-based cytology (LBC) and CS as well as Fuhrman nuclear grading (FNG) was carried out. Immunocytochemistry was performed from normal and CRCC cytology specimens.

Results: Normal renal cytology (NRC) showed no significant morphological differences between LBC and CS. For CRCC, LBC showed small, fragmented cell clusters, a 3-dimensional configuration, distinct cytoplasmic vacuoles, and irregular nuclear contours when compared with CS. FNG was overgraded with LBC compared to with CS. AMACR was the most valuable immunocytochemical marker for distinguishing CRCC from NRC.

Conclusion: Once cytopathologists become familiar with the altered cytomorphological features of CRCC, FNAC, along with immunocytochemistry, may prove helpful for diagnosis.
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http://dx.doi.org/10.1159/000430081DOI Listing
January 2016

Possible additional antidepressant-like mechanism of sodium butyrate: targeting the hippocampus.

Neuropharmacology 2014 Jun 5;81:292-302. Epub 2014 Mar 5.

Department of Pharmacology, School of Medicine, CHA University, 222 Yatap-dong, Bundang-gu, Seongnam-si, Gyeonggi-do 463-836, South Korea. Electronic address:

Chromatin remodeling mediated by histone acetylation might be involved in the pathophysiology and the treatment of depression. Recently, it has been reported that the histone deacetylase (HDAC) inhibitors, such as sodium butyrate (SB), could be a potential therapeutic agent for depression treatment. In the present study, we aimed to clarify the antidepressant mechanism of SB in the hippocampus. The mice were exposed to chronic restraint stress (CRS) for 14 consecutive days (2 h/day) to induce depression-like behaviors. To assess depression-like behaviors, sucrose preference test, light dark test (LD), tail suspension test (TST), and forced swim test (FST) were performed after CRS. We observed that CRS decreased HDAC2 and 5 mRNA and protein levels in the hippocampus. In addition, SB co-treatment decreased the depression-like behaviors that are induced by CRS. SB prevented and normalized the phosphorylation of cAMP response element binding protein (pCREB), acetylation of histone H3 (AceH3), HDAC2, and brain-derived neurotrophic factor (BDNF) expression level that were decreased by CRS in the hippocampus. These results suggest that the decreased HDAC2 and 5 expressions in the hippocampus of CRS may be a type of spontaneous coping response against CRS. However, it seems to be unsuccessful to prevent depression induction since reduction of pCREB, AceH3 and BDNF were accompanied by CRS in the hippocampus. Moreover, the reduced AceH3 level may be associated with the decreased pCREB, which appears to lead to the decreased BDNF.
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http://dx.doi.org/10.1016/j.neuropharm.2014.02.017DOI Listing
June 2014

CXC motif ligand 12 as a novel diagnostic marker for papillary thyroid carcinoma.

Head Neck 2014 Jul 18;36(7):1005-12. Epub 2013 Sep 18.

Department of Pathology, Cancer Center, Dongnam Institute of Radiological and Medical Sciences (DIRAMS), Busan, South Korea.

Background: We subjected chemokine (C-X-C motif) ligand 12 (CXCL12) to immunohistochemistry to determine its utility as a novel diagnostic marker for papillary thyroid carcinoma (PTC) in comparison to cytokeratin 19 (CK19), Hector Battifora mesothelial epitope-1 (HBME-1), and galectin-3.

Methods: We analyzed the expressions of CXCL12, CK19, HBME-1, and galectin-3 using immunohistochemical staining in 258 cases of thyroid lesions (196 PTCs and 62 thyroid lesions excluding PTC).

Results: Remarkably, CXCL12 expression was exclusively found in PTC compared to other thyroid lesions (90.8% vs 3.2%; p < .001). In total, 91.1% (62 of 68) of the variant PTCs and 90.6% of conventional type (116 of 128) were associated with CXCL12 immunohistochemical expression, irrespective of the histological subtype. In contrast, very few of the thyroid lesions, excluding PTC, were positive for CXCL12 (2 of 62; 3.2%). Diagnostic performances for PTCs were as follows: sensitivity, 90.8%; specificity, 96.8%; positive predictive value, 98.9%; negative predictive value, 76.9%; and diagnostic accuracy, 92.2%.

Conclusion: Our findings indicate that CXCL12 might serve as an effective novel supplementary diagnostic marker for PTC.
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http://dx.doi.org/10.1002/hed.23404DOI Listing
July 2014

Cytomorphological factors and BRAF mutation predicting risk of lymph node metastasis in preoperative liquid-based fine needle aspirations of papillary thyroid carcinoma.

Acta Cytol 2013 25;57(3):252-8. Epub 2013 Apr 25.

Department of Pathology, Cancer Center, Dongnam Institute of Radiological and Medical Sciences, Busan, South Korea.

Objective: Preoperative fine needle aspiration biopsy (FNAB) has become the initial diagnostic method for papillary thyroid carcinoma (PTC). Identification of cytomorphologic factors predicting lymph node metastasis (LNM) is clinically important for determining the appropriate treatment regimen due to the high rate of lymph node involvement in PTC at the time of diagnosis. Hobnail features (HF) have previously been described as potential histomorphologic features in the histological examination of PTC. This study evaluated the value of HF as a predictor of LNM.

Study Design: Histologically confirmed FNABs (n = 111) of papillary thyroid microcarcinoma prepared by the liquid-based method were enrolled. Along with other cytomorphologic parameters, HF were evaluated for their value in predicting LNM.

Results: Although HF were closely correlated with cytoplasmic vacuoles of tumor cells and background macrophages (p < 0.05), which were considered diagnostic indicators of PTC with cystic changes, HF were only found to be significantly correlated with LNM (p = 0.008). The BRAF(V660E) mutation was not associated with LNM. All combinations including HF were revealed as stronger predictors of LNM (odds ratios: 2.254-2.524, p < 0.05).

Conclusions: HF, a distinctive cytomorphologic feature, may be used as a factor predicting LNM in preoperative FNAB of PTC.
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http://dx.doi.org/10.1159/000343617DOI Listing
July 2013

A peptide vaccine based on a B-cell epitope on the VP1 protein of enterovirus 70 induces a strong antibody response.

Acta Virol 2012 ;56(4):337-42

The Catholic University of Korea, Gyeonggi-do, Korea.

Enterovirus 70 (EV70) is the causative agent of acute hemorrhagic conjunctivitis (AHC), for which no effective vaccine is available. This study revealed a high reactivity of the N-terminal region of EV70 VP1 (VP1-1) with an anti-EV70 mouse serum. The analysis of overlapping synthetic peptides of VP1-1 identified a B-cell epitope in this region. The E-peptide (14-ANTVESEIKAELGVI-28) showing the highest reactivity with the anti-EV70 serum induced neutralizing antibodies in mice and reduced the virus titer in the eyes, suggesting that it is a candidate vaccine against AHC caused by EV70.
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http://dx.doi.org/10.4149/av_2012_04_337DOI Listing
March 2013

The role of neuronal nitric oxide synthase on hypobaric hypoxia-induced antinociception in writhing test.

Arch Pharm Res 2010 Jul 27;33(7):1103-10. Epub 2010 Jul 27.

Department of Pharmacology, Institute of Natural Medicine, Hallym University, ChunCheon, Korea.

It has been reported that hypobaric hypoxia exposure by high altitude is responsible for neuropsychological impairment. In the present study, we examined an effect of hypobaric hypoxia on the writhing test. The ICR mice were exposed in hypobaric chamber with several altitudes (5000, 10,000 or 20,000 ft) for 1 or 2 h, and then immediately injected intraperitoneally (i.p.) with 1% acetic acid for writhing test. Our results show that both 10,000 ft and 20,000 ft exposure induce antinociceptive effect in writhing test, but 5,000 ft does not. In addition, this antinociceptive effect was abolished by L-NAME (nitric oxide synthase inhibitor) pre-treated intraperitoneally, but not naloxone (non-specific opioid receptor antagonist). Furthermore, we examined that neuronal NOS immunoreactivities in the hypothalamus (paraventricular nucleus and arcuate nucleus) were increased by hypobaric hypoxic exposure (10,000ft). These results suggest that hypobaric hypoxic-induced antinociception may be associated with neuronal NOS IR in the hypothalamus.
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http://dx.doi.org/10.1007/s12272-010-0717-0DOI Listing
July 2010

Spontaneously infarcted fibroadenoma mimicking breast cancer.

J Ultrasound Med 2009 Oct;28(10):1421-3

Department of Radiology, Kangnam Sacred Heart Hospital, College of Medicine, Hallym University, Seoul, Korea.

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http://dx.doi.org/10.7863/jum.2009.28.10.1421DOI Listing
October 2009

Imaging findings of primary well-differentiated liposarcoma of the liver: a case report.

Acta Radiol 2007 Dec;48(10):1061-5

Department of Radiology, Department of Pathology, Hallym University College of Medicine, Kangnam Sacred Heart Hospital, Seoul, Korea.

Primary liposarcoma of the liver is extremely rare. We report here on a case of primary well-differentiated liposarcoma in the left hepatic lobe of a 63-year-old woman. Abdominal ultrasonography showed a well-defined, echogenic, round mass. Abdominal computed tomography (CT) and magnetic resonance (MR) images showed an almost fatty, lobulated mass with a few, random distributed vascular structures and a small area of nodular enhancement. The resected tumor appeared as a well-defined, round, tan-yellow mass. Histological analysis showed a well-differentiated liposarcoma.
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http://dx.doi.org/10.1080/02841850701630334DOI Listing
December 2007

Linear polyp measurement at CT colonography: 3D endoluminal measurement with optimized surface-rendering threshold value and automated measurement.

Radiology 2008 Jan 21;246(1):157-67. Epub 2007 Nov 21.

Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1 Poongnap-Dong, Songpa-Gu, Seoul 138-040, Korea.

Purpose: To determine the optimal surface-rendering threshold value for three-dimensional (3D) endoluminal computed tomographic (CT) colonographic images for accurate manual polyp measurement, with direct measurement of simulated polyps as the reference standard, and to assess the agreement between manual 3D measurements and automated measurements.

Materials And Methods: Institutional review board approval was not required for the experimental study with pig colons obtained at an abattoir but was obtained for the use of patient data, with waiver of informed consent. Eighty-six simulated polyps (reference size, 3-15 mm) and 14 human polyps (approximate size, 5-20 mm) were included. Automated polyp measurements and manual measurements with endoluminal views that were surface rendered at threshold values of -800, -700, -600, and -500 HU were performed by one observer. Agreement between CT colonographic measurements and reference sizes and between manual and automated measurements were assessed by using the Bland-Altman method.

Results: For simulated polyps, mean measurement difference between the observed size and reference size was 0.86 mm (95% limits of agreement: -0.52 mm, 2.24 mm), 0.55 mm (95% limits of agreement: -0.75 mm, 1.85 mm), 0.20 mm (95% limits of agreement: -1.11 mm, 1.50 mm), and -0.08 mm (95% limits of agreement: -1.43 mm, 1.27 mm) for -800, -700, -600, and -500 HU, respectively. Mean measurement difference was 0.09 mm (95% limits of agreement: -1.49 mm, 1.67 mm) for automated measurement. Manual polyp size at -500 HU (P = .277) and automated polyp size (P = .288) were not significantly different from reference size. For human polyps, 10 polyps, excluding four lesions that were large, lobulated, or located adjacent to an edge of the haustral fold, showed accurate automated demarcation of lesion boundaries. Automated measurements of the 10 polyps showed the closest agreement with manual measurements at -500 HU.

Conclusion: The optimal surface-rendering threshold value for accurate polyp measurement is approximately -500 HU. Automated measurements agree closely with manual measurements at the optimal threshold value for well-circumscribed smooth rounded polyps.
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http://dx.doi.org/10.1148/radiol.2453061930DOI Listing
January 2008

Differentiating benign from malignant solid breast masses: comparison of two-dimensional and three-dimensional US.

Radiology 2006 Jul 9;240(1):26-32. Epub 2006 May 9.

Department of Radiology and Clinical Research Institute, Seoul National University Hospital, 28 Yongon-dong, Chongno-gu, Seoul 100-744, Korea.

Purpose: To compare prospectively obtained static two-dimensional (2D) and three-dimensional (3D) ultrasonographic (US) images in the diagnostic performance of radiologists with respect to the differentiation of benign from malignant solid breast masses with histopathologic examination as the reference standard.

Materials And Methods: This study had institutional review board approval, and patient informed consent was obtained. Conventional 2D and 3D US images were obtained from 141 patients (age range, 25-71 years; mean age, 46 years) with 150 solid breast masses (60 cancers and 90 benign lesions) before excisonal or needle biopsy. Four radiologists who had not performed the examinations independently reviewed 2D US images and stored 3D US data and provided a level of suspicion concerning probability of malignancy. The sensitivity, specificity, and negative predictive values of 2D images were compared with those of 3D US images.

Results: For all readers, 3D US images were the same as or better than 2D US images in terms of sensitivity (100% vs 100% for reader 1; 100% vs 98% for reader 2; 98% vs 93% for reader 3; 93% vs 92% for reader 4), specificity (58% vs 56% for reader 1; 51% vs 46% for reader 2; 83% vs 72% for reader 3; 86% vs 84% for reader 4), and negative predictive values (100% vs 100% for reader 1; 100% vs 98% for reader 2; 99% vs 94% for reader 3; 95% vs 94% for reader 4). These differences, however, were not statistically significant (P > .05).

Conclusion: The performance of the radiologists with respect to the characterization of solid breast masses with static 2D US images was similar to that with 3D US data.
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http://dx.doi.org/10.1148/radiol.2401050743DOI Listing
July 2006

Neurobehavioral performance in workers exposed to toluene.

Environ Toxicol Pharmacol 2005 May;19(3):645-50

Center for Occupational Diseases Research, Occupational Safety and Health Research Institute, Korea Occupational Safety and Health Agency (KOSHA), 34-6 Gusan-dong Bupyong-gu, Incheon 403-711, Republic of Korea.

Toluene is widely used in adhesive, printing, painting and petroleum industries in many countries. This study was conducted to examine the effect of chronic exposure to toluene below 100ppm on neurobehavioral performance using a computerized neurobehavioral test battery that emphasizes simple instructions and practice prior to testing. The Behavioral Assessment and Research System (BARS) with Korean language instructions was administered to 54 workers from three different industries: oil refinery, gravure printing, and rubber boat manufacturing. The battery consisted of the following tests: Digit Span (DS), Simple Reaction Time (SRT), Selective Attention (SAT), Finger Tapping (FT), and Symbol Digit (SD). Urine was collected at the end-of-shift to analyze urinary hippuric acid to assess exposure level to toluene. Based on the previous air toluene level, workers were divided into three groups: Low (21 workers, less than 10ppm), Moderate (13 workers, 20-30ppm) and High (20 workers, 70-80ppm) exposure status. Analysis of Covariance (ANCOVA) adjusting for age, education and work duration as covariates, was performed to examine the relationship between the neurobehavioral performance and the exposure groups. Poorer performance of the High exposure group was found on FT-preferred (F=7.034, p=0.002) and SAT latency (F=11.710, p=0.000). Age showed a significant correlation with SD (r=0.417, p=0.002) and SAT number correct (r=-0.460, p=0.000). Years of education and work duration were not significantly correlated with any items. This study supports that toluene exposure below 100ppm is associated with neurobehavioral changes and that high-level toluene exposure could cause not only attention and concentration, but also motor performance deficits.
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http://dx.doi.org/10.1016/j.etap.2004.12.049DOI Listing
May 2005

Inflammatory breast cancer: imaging findings.

Clin Imaging 2005 Jan-Feb;29(1):22-5

Department of Radiology, Seoul National University, Bundang Hospital, Bundang-Gu, Seongnam-si, Gyeonggi-do 463-707, South Korea.

To assess the imaging findings of inflammatory breast cancer, we retrospectively analyzed the mammography, ultrasonography, and magnetic resonance imaging (MRI) findings of nine patients with inflammatory breast cancer. Inflammatory breast cancer showed skin thickening and nipple-areolar swelling on mammography, ultrasonography, and MRI. Tumor with lymphatic dilatation on ultrasonography and enhancement of thickened skin and parenchyma on MRI can be useful findings in the diagnosis of inflammatory breast cancer.
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May 2005