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Current Status and Research into Overcoming Limitations of Capsule Endoscopy
Won Gun Kwack,Yun Jeong Lim 대한소화기내시경학회 2016 Clinical Endoscopy Vol.49 No.1
Endoscopic investigation has a critical role in the diagnosis and treatment of gastrointestinal (GI) diseases. Since 2001, capsule endoscopy (CE) has been available for small-bowel exploration and is under continuous development. During the past decade, CE has achieved impressive improvements in areas such as miniaturization, resolution, and battery life. As a result, CE is currently a first-line tool for the investigation of the small bowel in obscure gastrointestinal bleeding and is a useful alternative to wired enteroscopy. Nevertheless, CE still has several limitations, such as incomplete examination and limited diagnostic and therapeutic capabilities. To resolve these problems, many groups have suggested several models (e.g., controlled CO2 insufflation system, magnetic navigation system, mobile robotic platform, tagging and biopsy equipment, and targeted drug-delivery system), which are in development. In the near future, new technological advances will improve the capabilities of CE and broaden its spectrum of applications not only for the small bowel but also for the colon, stomach, and esophagus. The purpose of this review is to introduce the current status of CE and to review the ongoing development of solutions to address its limitations.
Yun, Byung Ju,Koh, Won-Gun Elsevier 2020 Journal of industrial and engineering chemistry Vol.82 No.-
<P><B>Abstract</B></P> <P>A new, highly sensitive surface enhanced Raman scattering (SERS)-based immunoassay platform was prepared using silver nanoparticle (AgNP)-decorated electrospun fibers as the capture substrate. We used electrospinning and silver mirror reaction to generate AgNP-decorated polycaprolactone (PCL) fiber matrix (Ag-PCL). The resultant capture substrates obtained were bi-directionally porous, free-standing, and flexible. AgNP formation on the PCL fibers was confirmed via SEM, AFM, XPS, and TGA analysis. In addition, gold nanoparticles immobilized with a Raman reporter, 4-mercaptobenzoic acid (4-MBA), were prepared as the SERS tag. This tag could significantly enhance the SERS signal via generation of additional hot spots between AgNPs on fibers and AuNPs. For a model immunoassay to detect prostate specific antigen (PSA), PSA antibodies were immobilized on both Ag-PCL and AuNP SERS tags. The large surface area of fiber substrates allowed the immobilization of large amounts of antibodies and their porous structures facilitated the assessment of the target antigen to immobilized antibodies. Binding of PSA between antibodies on AgNPs and AuNPs led to formation of a sandwich structure by the two metal nanostructures, and consequently, highly sensitive detection of PSA was possible up to a detection limit of 1pg/mL within 1h of reaction time. The developed SERS-based immunoassay platform produced uniform and reproducible SERS signals over the entire substrate area and from different samples.</P> <P><B>Highlights</B></P> <P> <UL> <LI> SERS-based immunoassay was carried out using AgNP-decorated electrospun fibers as capture substrate. </LI> <LI> SERS signal was greatly amplified by the generation of hot spots between AgNPs on fibers and AuNP-based SERS tag. </LI> <LI> Fast and sensitive detection of PSA was possible due to the large surface area and porous structure of fibrous substrate. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Deletion of xylR Gene Enhances Expression of Xylose Isomerase in Streptomyces lividans TK24
( Gun Young Heo ),( Won Chan Kim ),( Gil Jae Joo ),( Yun Young Kwak ),( Jae Ho Shin ),( Dong Hyun Roh ),( Heui Dong Park ),( In Koo Rhee ) 한국미생물 · 생명공학회 2008 Journal of microbiology and biotechnology Vol.18 No.5
Yun, Sung-Ho,Choi, Chi-Won,Kwon, Sang-Oh,Park, Gun Wook,Cho, Kun,Kwon, Kyung-Hoon,Kim, Jin Young,Yoo, Jong Shin,Lee, Je Chul,Choi, Jong-Soon,Kim, Soohyun,Kim, Seung Il American Chemical Society 2011 Journal of proteome research Vol.10 No.2
<P><I>Acinetobacter baumannii</I> is a Gram-negative, nonmotile aerobic bacterium that has emerged as an important nosocomial pathogen. Multidrug-resistant (MDR) <I>A. baumannii</I> is difficult to treat with antibiotics, and treatment failure in infected patients is of great concern in clinical settings. To investigate proteome regulation in <I>A. baumannii</I> under antibiotic stress conditions, quantitative membrane proteomic analyses of a clinical MDR <I>A. baumannii</I> strain cultured in subminimal inhibitory concentrations of tetracycline and imipenem were performed using a combination of label-free (one-dimensional electrophoresis-liquid chromatography−tandem mass spectrometry) and label (isobaric tag for relative and absolute quantitation) approaches. In total, 484 proteins were identified, and 302 were classified as outer membrane, periplasmic, or plasma membrane proteins. The clinical <I>A. baumannii</I> strain DU202 responded specifically and induced different cell wall and membrane protein sets that provided resistance to the antibiotics. The induction of resistance-nodulation-cell division transporters and protein kinases, and the repression of outer membrane proteins were common responses in the presence of tetracycline and imipenem. Induction of a tetracycline resistant pump, ribosomal proteins, and iron-uptake transporters appeared to be dependent on tetracycline conditions, whereas β-lactamase and penicillin-binding proteins appeared to be dependent on imipenem conditions. These results suggest that combined liquid chromatography-based proteomic approaches can be used to identify cell wall and membrane proteins involved in the antibiotic resistance of <I>A. baumannii</I>.</P><P><I>Acinetobacter baumannii</I> is a Gram-negative, nonmotile aerobic bacterium that has emerged as an important nosocomial pathogen. To investigate proteome regulation in <I>A. baumannii</I> under antibiotic stress conditions, quantitative membrane proteomic analyses of a clinical multidrug-resistant <I>A. baumannii</I> strain cultured in subminimal inhibitory concentrations of tetracycline and imipenem were performed. Our results suggest that combined liquid chromatography-based proteomic approaches can be used to identify cell wall and membrane proteins involved in the antibiotic resistance of <I>A. baumannii</I>.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jprobs/2011/jprobs.2011.10.issue-2/pr101012s/production/images/medium/pr-2010-01012s_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/pr101012s'>ACS Electronic Supporting Info</A></P>
Gene Expression Analysis of Pregnant Specific Stage in the Miniature Pig Ovary
Yun, Seong-Jo,Noh, Won-Gun,Yoon, Jong-Taek,Min, Kwan-Sik The Korean Society of Animal Reproduction 2009 Reproductive & developmental biology Vol.33 No.4
The miniature pig is considered to be a better organ donor breed for xenotransplantation than other pig breeds because the size of the organs of the miniature pig is similar to that of humans. In this study, we aimed at identifying differentially expressed genes in the miniature pig ovary during pregnancy. For this, we used the miniature pig ovary model, annealing control primer-based reverse transcription polymerase chain reaction (PCR), quantitative real-time PCR (qRT-PCR), and northern blotting analysis. We identified 13 genes showing differential expression on the based of pregnancy status and validated 8 genes using qRT-PCR. We also sequenced the full-length cDNA of ephrin receptor A4 (EphA4), which had a significant difference in expression level, and validated it by northern blotting. These genes may provide a better understanding of the cellular and molecular mechanisms during pregnancy in miniature pig ovary.
Yun, Won-Gun,Lim, Myung-Hoon,Kim, Sarah,Kim, Sa-Hong,Park, Ji-Hyeon,Kong, Seong-Ho,Park, Do Joong,Lee, Hyuk-Joon,Yang, Han-Kwang The Korean Gastric Cancer Association 2021 Journal of gastric cancer Vol.21 No.2
Purpose: The aim of this study was to investigate the oncologic safety and identify potential candidates for proximal gastrectomy (PG) in upper third advanced gastric cancer (AGC) and esophagogastric junction (EGJ) cancers. Materials and Methods: Among 5,665 patients who underwent gastrectomy for gastric adenocarcinoma between January 2011 and December 2017, 327 patients who underwent total gastrectomy with standard lymph node (LN) dissection for upper third AGC and Siewert type II EGJ cancers were enrolled. We analyzed the correlation between the metastatic rates of distal LNs (No. 4d, 5, 6, and 12a) around the lower part of the stomach and the clinicopathological characteristics. We identified subgroups with no metastasis to the distal LNs. Results: The metastatic rate of distal LNs in proximal AGC and Siewert type II EGJ cancers was 7.0% (23 of 327 patients). On multivariate analysis, pathological T stage (P=0.001), tumor size (P=0.043), and middle third invasion (P=0.003) were significantly associated with distal LN metastases. Pathological 'T2 stage' (n=88), or 'T3 stage with ≤5 cm tumor size' (n=87) showed no metastasis in distal LNs, regardless of middle third invasion. Pathological T3 stage with tumor size > 5 cm (n=61) and T4 stage (n=91) had metastasis in the distal LNs. Conclusions: In the upper third AGC and Siewert type II EGJ cancer, pathological T2 and small-sized T3 stage groups are possible candidates for PG in cases without distal LN metastasis. Further validation studies are required for clinical application.
Won Gun Kwack,Yun Jeong Lim,Ki Hwan Kwon,Jae Woo Chung,Jin Young Oh 대한내과학회 2020 The Korean Journal of Internal Medicine Vol.35 No.2
Background/Aims: Diagnostic stool multiplex polymerase chain reaction (PCR) testing has attracted considerable interest, because of its high sensitivity, short turnaround time, and ability to detect multiple organisms simultaneously. This study investigates the clinical usefulness of a stool multiplex bacterial PCR in patients with acute diarrhea. Methods: We retrospectively evaluated the stool multiplex bacterial PCR results, clinical parameters, and clinical courses of patients hospitalized because of acute diarrhea between August 2014 and November 2016. Results: A total of 725 patients (male, 372; mean age, 30.9 ± 29.3 years) underwent stool multiplex bacterial PCR. A total of 243 pathogens were detected in 226 patients. The detection rate of multiplex PCR testing was higher than that of stool culture (32.7% vs. 3.3%, p < 0.01). Severe symptoms of acute diarrhea (bloody diarrhea, frequent diarrhea) and prescribed empirical antibiotics were significantly more common in the positive multiplex PCR group (p = 0.02, p < 0.01, p < 0.01, respectively). However, mean durations of hospital stay were similar in the 2 groups according to the multiplex PCR results (p = 0.32). In addition, Campylobacter spp., which was the most commonly detected pathogen (97/243, 39.9%), was significantly associated with frequent diarrhea and prescribed empirical antibiotics (p < 0.01), but not with duration of hospital stay (p = 0.09). Conclusions: We concluded that stool multiplex bacterial PCR might be a useful tool for identifying bacterial etiology in patients with acute diarrhea, especially in those with Campylobacter spp. infection.