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Helicobacter pylori (H. pylori) infection is one of the most common infectious diseases worldwide. Although its incidence is gradually decreasing, about half of the world''s population still get infected. H. pylori infection is responsible for substantial gastrointestinal morbidity worldwide. It is the most common cause of gastric and duodenal ulcers as well as gastric cancer. Since the revision of the H. pylori Clinical Practice Guidelines in 2013, the eradication rate of H. pylori has gradually decreased with the use of classical triple therapy, wherein amoxicillin, clarithromycin, and proton pump inhibitors are administered, for 7 days. According to a nationwide randomized controlled study conducted by the Korean College of Helicobacter and Upper Gastrointestinal Research released in 2018, the intention-to-treat eradication rate was only 63.9%, which was due to increased antimicrobial resistance induced by the use of antibiotics, especially clarithromycin. The update of clinical practice guideline for treatment of H. pylori was developed based on evidence-based medicine by conducting a meta-analysis. The draft recommendations were finalized after expert consensus on three recommendations regarding the indication for treatment and eight recommendations on the treatment itself. These guidelines are designed to provide patients, nurses, medical school students, policymakers, and clinicians with clinical evidence to guide primary care and treatment of H. pylori infection. These may differ from current medical insurance standards and will be revised further, if necessary, based on research-based evidence. (Korean J Med 2021;96:160-189)

Background/Aims: Functional dyspepsia (FD) is a chronic upper gastrointestinal symptom complex that routine diagnostic work-up, such as endoscopy, blood laboratory analysis, or radiological examination, fails to identify a cause for. It is highly prevalent in the Korean population, and its response to the various available therapeutic strategies is only modest because of the heterogeneous nature of its pathogenesis. We constituted a guidelines development committee to review the existing guidelines on the management of FD.Methods: This committee drafted statements and conducted a systematic review and meta-analysis of various studies, guidelines, and randomized control trials. External review was also conducted by selected experts. These clinical practice guidelines for FD were developed based on evidence recently accumulated with the revised version of FD guidelines released in 2011 by the Korean Society of Neurogastroenterology and Motility.Results: These guidelines apply to adults with chronic symptoms of FD and include the diagnostic role of endoscopy, Helicobacter pylori screening, and systematic review and meta-analyses of the various treatment options for FD (proton pump inhibitors, Helicobacter pylori eradication, and tricyclic antidepressants), especially according to the FD subtype.Conclusions: The purpose of these new guidelines is to aid understanding, diagnosis, and treatment of FD, and the targets of the guidelines are clinicians, healthcare workers at the forefront of patient care, patients, and medical students. The guidelines will continue to be revised and updated periodically.

Helicobacter pylori infection is one of the most common infectious diseases worldwide. Although the prevalence of H. pylori is gradually decreasing, approximately half of the world's population still becomes infected with this disease. H. pylori is responsible for substantial gastrointestinal morbidity worldwide, with a high disease burden. It is the most common cause of gastric and duodenal ulcers and gastric cancer. Since the revision of the H. pylori clinical practice guidelines in 2013 in Korea, the eradication rate of H. pylori has gradually decreased with the use of a clarithromycin-based triple therapy for 7 days. According to a nationwide randomized controlled study conducted by the Korean College of Helicobacter and Upper Gastrointestinal Research released in 2018, the intention-to-treat eradication rate was only 63.9%, which was mostly due to increased antimicrobial resistance, especially from clarithromycin. The clinical practice guidelines for the treatment of H. pylori were updated according to evidence-based medicine from a meta-analysis conducted on a target group receiving the latest level of eradication therapy. The draft recommendations developed based on the meta-analysis were finalized after an expert consensus on three recommendations regarding the indication for treatment and eight recommendations for the treatment itself. These guidelines were designed to provide clinical evidence for the treatment (including primary care treatment) of H. pylori infection to patients, nurses, medical school students, policymakers, and clinicians. These may differ from current medical insurance standards and will be revised if more evidence emerges in the future.

Background/Aims: As antibiotic resistance increases and new first-line therapies emerge, salvage therapies for Helicobacter pylori (H. pylori) eradication failures are becoming more common and complicated. This study aimed to systematically review overall salvage regimens after previous failure of H. pylori eradication.Materials and Methods: A systematic review of randomized clinical trials evaluating salvage therapies after previous H. pylori eradication failure was performed. A meta-analysis was conducted when an adequate number of studies suitable for grouping was found.Results: Overall, 36 studies with 77 treatment arms were identified, and they were highly heterogeneous regarding previously failed regimens and salvage regimens under comparison. Bismuth quadruple therapy after failure of standard triple therapy showed a pooled intention-to-treat (ITT) eradication rate of 75.5% (95% CI, 71.6~79.1%), and the rates were significantly higher with 14-day therapy than 7-day therapy by 9% (95% CI, 2~15%). Levofloxacin triple therapy after failure of standard triple therapy demonstrated a pooled ITT eradication rate of 73.3% (95% CI, 68.4~77.3%). In direct comparison, the two regimens were not significantly different in eradication rates. No study evaluated salvage regimens after the failure of bismuth or non-bismuth quadruple therapy.Conclusions: The current studies regarding salvage regimens are highly heterogeneous. Bismuth quadruple therapy and levofloxacin triple therapy may be a reliable option after failure of standard triple therapy, but the regional profile of antibiotic resistance should be considered. Further studies are needed for salvage regimens after failure of non-bismuth or bismuth quadruple therapy.

Background/Aims: The eradication rate of the first-line standard triple therapy (STT) for Helicobacter pylori (H. pylori) infection has decreased since 2000; therefore, other first-line therapies are required. This study was aimed at investigating the efficacy of bismuth-containing quadruple therapy (PBMT) for first-line H. pylori eradication compared to STT, sequential therapy (SQT), and concomitant therapy (CT).Materials and Methods: The Ovid-MEDLINE, Koreamed, EMBASE, KMBASE, and Cochrane Library databases were searched from January 2008 to July 2018. All identified randomized controlled trials (RCTs) comparing PBMT and non-PBMT for first-line H. pylori eradication therapy were included in the final analysis.Results: A total of 3,653 patients from seven RCTs were enrolled. The pooled eradication rates of PBMT by intention-to-treat (ITT) and per-protocol (PP) analyses were 82.1% (95% CI, 68.2~90.8%) and 88.8% (95% CI, 77.1~94.9%), respectively. However, no statistically significant difference was observed in eradication rates of the 10- or 14-day PBMT as compared to 14-day STT, 10-day SQT, and 10-day CT in ITT and PP analyses. PBMT was significantly higher in adverse events than in the other eradication regimens (RR, 1.64; 95% CI, 1.11~2.44). Considerable heterogeneity in adverse events was observed among studies (χ2=88.7; P2=93%).Conclusions: PBMT can be the first-line treatment for H. pylori eradication in Korea when other first-line options, including STT, SQT, or CT, are unavailable due to their high adverse event rates.

Background/Aims: Standard triple therapy, including a proton pump inhibitor, clarithromycin, and amoxicillin, has been recommended as the first-line for Helicobacter pylori infection. However, the eradication rate of standard triple therapy has declined over the past years because of the increasing resistance to clarithromycin in Korea. We analyzed the eradication rates and the 10-year change in the eradication rates in Korea.Methods: PubMed, EMBASE, the Cochrane Library, and KoreaMed were searched for studies published between January 2007 and June 2018. The pooled eradication rates and their 95% CIs were estimated using a random-effect logistic regression model.Results: Twenty-six randomized controlled studies on standard triple therapy conducted in Korea were selected. The intention-to-treat (ITT) and per protocol analyses showed pooled eradication rates of standard triple therapy of 71.6% (95% CI, 69.9~73.3%) and 79.6% (95% CI, 76.6~82.2%), respectively. The eradication rate decreased with time. The ITT analysis showed that the 14-day therapy (78.1% [95% CI, 75.2~80.7%]) had significantly higher eradication rates than the 7-day therapy (70.0% [95% CI, 68.5~71.4%]) (P

Esophageal achalasia is a primary motility disorder characterized by insufficient lower esophageal sphincter relaxation and loss of esophageal peristalsis. Achalasia is a chronic disease that causes progressive irreversible loss of esophageal motor function. The recent development of high-resolution manometry has facilitated the diagnosis of achalasia, and determining the achalasia subtypes based on high-resolution manometry can be important when deciding on treatment methods. Peroral endoscopic myotomy is less invasive than surgery with comparable efficacy. The present guidelines (the "2019 Seoul Consensus on Esophageal Achalasia Guidelines") were developed based on evidence-based medicine; the Asian Neurogastroenterology and Motility Association and Korean Society of Neurogastroenterology and Motility served as the operating and development committees, respectively. The development of the guidelines began in June 2018, and a draft consensus based on the Delphi process was achieved in April 2019. The guidelines consist of 18 recommendations: 2 pertaining to the definition and epidemiology of achalasia, 6 pertaining to diagnoses, and 10 pertaining to treatments. The endoscopic treatment section is based on the latest evidence from meta-analyses. Clinicians (including gastroenterologists, upper gastrointestinal tract surgeons, general physicians, nurses, and other hospital workers) and patients could use these guidelines to make an informed decision on the management of achalasia.

Functional dyspepsia (FD) is a chronic upper gastrointestinal (GI) symptom complex that routine diagnostic work-up, such as endoscopy, blood laboratory analysis, or radiological examination, fails to identify a cause. It is highly prevalent in the World population, and its response to the various available therapeutic strategies is only modest because of the heterogenous nature of its pathogenesis. Therefore, FD represents a heavy medical burden for healthcare systems. We constituted a guideline development committee to review the existing guidelines on the management of functional dyspepsia. This committee drafted statements and conducted a systematic review and meta-analysis of various studies, guidelines, and randomized control trials. External review was also conducted by selected experts. These clinical practice guidelines for FD were developed based on evidence recently accumulated with the revised version of FD guidelines released in 2011 by the Korean Society of Neurogastroenterology and Motility. These guidelines apply to adults with chronic symptoms of FD and include the diagnostic role of endoscopy, Helicobacter pylori screening, and systematic review and meta-analyses of the various treatment options for FD (proton pump inhibitors, H. pylori eradication, and tricyclic antidepressants), especially according to the FD subtype. The purpose of these new guidelines is to aid the understanding, diagnosis, and treatment of FD, and the targets of the guidelines are clinicians, healthcare workers at the forefront of patient care, patients, and medical students. The guidelines will continue to be revised and updated periodically.

Helicobacter pylori infection is one of the most common infectious diseases world wide. H. pylori is responsible for substantial gastrointestinal morbidity with a high disease burden. Since the revision of the H. pylori Clinical Practice Guide lines in 2013 in Korea, the eradication rate of H. pylori has gradually decreased with the use of a clarithromycin based triple therapy. According to a nationwide randomized controlled study by the Korean College of Helicobacter and Upper Gastrointestinal Research released in 2018, the intention-to-treat eradication rate was only 63.9%, which was mostly due to increased antimicrobial resistance to clarithromycin. The clinical practice guidelines for treatment of H. pylori were updated based on evidence-based medicine from a meta-analysis conducted on a target group receiving the latest level of eradication therapy. The draft recom mendations developed based on the meta-analysis were finalized after expert consensus on three recommendations regarding the indication for treatment and eight recommendations on the treatment itself. These guidelines were designed to provide clinical evidence for the treatment of H. pylori to patients, nurses, medical school students, policymakers, and clinicians. These may differ from current medical insurance standards, and will be revised if more evidence emerges in the future.

The human gastrointestinal tract contains a complex and dynamic population of microorganisms, known as the gut microbiota. Although interest in the role of the gut microbiota in human health has increased in recent years, there remains no standard sampling protocol for analyzing these organisms. Here, we aimed to characterize the microbial composition of distinct segments of the large intestine and to determine whether rectal swabs are suitable for identifying colon microbiota. A total of 100 participants who underwent screening colonoscopy from October 2019 to October 2020 were included in this study. Large intestinal samples (ascending colon, descending colon, sigmoid colon, and rectum) were aspirated by colonoscopy. Rectal swabs were collected before colonoscopy, and stool samples were collected before patients began colonoscopy preparation. All samples were subjected to 16S ribosomal RNA gene sequencing. We identified differences in the number of phylum-level operational taxonomic units among large intestinal samples, rectal swabs, and stool. Five major phyla were detected in all samples (Firmicutes, Bacteroides, Proteobacteria, Actinobacteria, Fusobacteria), although their relative abundances varied. Notably, we found that the microbial compositions of rectal swabs were most similar to those of the sigmoid colon and rectum, whereas the microbiota in stool were relatively different than those from the large intestine and rectal swabs. Our results reveal the existence of microbial heterogeneity within different large intestinal compartments and further suggest that rectal swabs are an acceptable and practical tool for gut microbiota analysis. KEY POINTS: • Our findings highlight local microbiome variations within different regions of the large intestine. • Stool samples do not appear to fully recapitulate the gut microbiome. • Our data from a large population-based cohort indicate that rectal swabs can be used to study the gut microbiome.

Gastroesophageal reflux disease (GERD) is a condition in which gastric contents regurgitate into the esophagus or beyond, resulting in either troublesome symptoms or complications. GERD is heterogeneous in terms of varied manifestations, test findings, and treatment responsiveness. GERD diagnosis can be established with symptomatology, pathology, or physiology. Recently the Lyon consensus defined the "proven GERD" with concrete evidence for reflux, including advanced grade erosive esophagitis (Los Angeles classification grades C and or D esophagitis), long-segment Barrett's mucosa or peptic strictures on endoscopy or distal esophageal acid exposure time > 6% on 24-hour ambulatory pH-impedance monitoring. However, some Asian researchers have different opinions on whether the same standards should be applied to the Asian population. The prevalence of GERD is increasing in Asia. The present evidence-based guidelines were developed using a systematic review and meta-analysis approach. In GERD with typical symptoms, a proton pump inhibitor test can be recommended as a sensitive, cost-effective, and practical test for GERD diagnosis. Based on a meta-analysis of 19 estimated acid-exposure time values in Asians, the reference range upper limit for esophageal acid exposure time was 3.2% (95% confidence interval, 2.7-3.9%) in the Asian countries. Esophageal manometry and novel impedance measurements, including mucosal impedance and a post-reflux swallow-induced peristaltic wave, are promising in discrimination of GERD among different reflux phenotypes, thus increasing its diagnostic yield. We also propose a long-term strategy of evidence-based GERD treatment with proton pump inhibitors and other drugs.

Background: The human gastrointestinal tract contains a complex and dynamic population of microorganisms, known as the gut microbiota. Critically, although interest in the role that the gut microbiota plays in human health has increased in recent years, there remains no standard sampling protocol for analyzing these organisms. Here, we aimed to characterize the microbial composition of distinct segments of the large intestine and to determine whether rectal swabs are suitable for identifying the colon microbiota. Methods: A total of 100 participants who underwent screening colonoscopy from October 2019 to October 2020 were included in this study. Large intestinal samples (ascending colon, descending colon, sigmoid colon, and rectum) were aspirated by colonoscopy. Rectal swabs were collected before colonoscopy, and stool samples were collected before patients began colonoscopy preparation. All samples were subjected to 16S ribosomal RNA gene sequencing. Findings: We identified differences in the number of phylum-level operational taxonomic units in large intestinal samples, rectal swabs, and stool. Five major phyla were detected in all samples (Firmicutes, Bacteroides, Proteobacteria, Actinobacteria, Fusobacteria), although their relative abundances varied. Notably, we found that the microbial composition of rectal swabs is most similar to those of the sigmoid colon and rectum, whereas the microbiota in stool are relatively different than those from the large intestine and rectal swabs. Interpretation: Our results reveal the existence of microbial heterogeneity within different large intestinal compartments and further suggest that rectal swabs are an acceptable and practical tool for gut microbiota analysis. Funding Information: This study was supported by MediCloud. Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: This study was approved by Yongin Severance Institutional Review Board (IRB No 9-2019-0014) and was performed in compliance with the Declaration of Helsinki. Written consent was obtained from all patients prior to participation.

Esophageal achalasia is a primary motility disorder characterized by insufficient lower esophageal sphincter relaxation and loss of esophageal peristalsis. Achalasia is a chronic disease that causes progressive irreversible loss of esophageal motor function. The recent development of high-resolution manometry has facilitated the diagnosis of achalasia, and determining the achalasia subtypes based on high-resolution manometry can be important when deciding on treatment methods. Peroral endoscopic myotomy is less invasive than surgery with comparable efficacy. The present guidelines (the “2019 Seoul Consensus on Esophageal Achalasia Guidelines”) were developed based on evidence-based medicine; the Asian Neurogastroenterology and Motility Association and Korean Society of Neurogastroenterology and Motility served as the operating and development committees, respectively. The development of the guidelines began in June 2018, and a draft consensus based on the Delphi process was achieved in April 2019. The guidelines consist of 18 recommendations: 2 pertaining to the definition and epidemiology of achalasia, 6 pertaining to diagnoses, and 10 pertaining to treatments. The endoscopic treatment section is based on the latest evidence from meta-analyses. Clinicians (including gastroenterologists, upper gastrointestinal tract surgeons, general physicians, nurses, and other hospital workers) and patients could use these guidelines to make an informed decision on the management of achalasia.

In 2011, the Korean Society of Neurogastroenterology and Motility (KSNM) published clinical practice guidelines on the management of irritable bowel syndrome (IBS) based on a systematic review of the literature. The KSNM planned to update the clinical practice guidelines to support primary physicians, reduce the socioeconomic burden of IBS, and reflect advances in the pathophysiology and management of IBS. The present revised version of the guidelines is in continuity with the previous version and targets adults diagnosed with, or suspected to have, IBS. A librarian created a literature search query, and a systematic review was conducted to identify candidate guidelines. Feasible documents were verified based on predetermined inclusion and exclusion criteria. The candidate seed guidelines were fully evaluated by the Guidelines Development Committee using the Appraisal of Guidelines for Research and Evaluation II quality assessment tool. After selecting 7 seed guidelines, the committee prepared evidence summaries to generate data exaction tables. These summaries comprised the 4 main themes of this version of the guidelines: colonoscopy; a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols; probiotics; and rifaximin. To adopt the core recommendations of the guidelines, the Delphi technique (ie, a panel of experts on IBS) was used. To enhance dissemination of the clinical practice guidelines, a Korean version will be made available, and a food calendar for patients with IBS is produced. (J Neurogastroenterol Motil 2018;24:197-215)

The Korean Society of Neurogastroenterology and Motility first published guidelines for chronic constipation in 2005 and was updated in 2011. Although the guidelines were updated using evidence-based process, they lacked multidisciplinary participation and did not include a diagnostic approach for chronic constipation. This study includes guidelines for diagnosis and treatment of chronic constipation to realistically fit the situation in Korea and to be applicable to clinical practice. The guideline development was based upon the adaptation method because research evidence was limited in Korea, and an organized multidisciplinary group carried out systematical literature review and series of evidence-based evaluations. Six guidelines were selected using the Appraisal of Guidelines for Research & Evaluation II process. A total 37 recommendations were adopted, including 4 concerning the definition and risk factors of chronic constipation, 8 regarding diagnoses, and 25 regarding treatments. The guidelines are intended to help primary physicians and general health professionals in clinical practice in Korea, to provide the principles of medical treatment to medical students, residents, and other healthcare professionals, and to help patients for choosing medical services based on the information. These guidelines will be updated and revised periodically to reflect new diagnostic and therapeutic methods. (Korean J Med 2016;91:114-130)

Background/aims A limited number of studies are available regarding the long-term natural history of post-infectious irritable bowel syndrome (PI-IBS). We aimed to investigate the long-term clinical course of PI-IBS. Methods A prospective cohort study was conducted from a 2001 shigellosis outbreak in a Korean hospital with about 2000 employees. A cohort of 124 hospital employees who were infected by Shigella sonnei due to contaminated food in the cafeteria, and 105 sex- and age-matched, non-infected, controls were serially followed for their bowel symptoms by questionnaire surveys for 10 years. Results The Shigella -infected cohort showed significantly higher odds ratio for irritable bowel syndrome (IBS) at 1-year (11.90; 95% CI, 1.49-95.58) and 3-year (3.93; 95% CI, 1.20-12.86) follow-up, compared to their controls. However, corresponding odds ratio for PI-IBS was not significantly increased at 5-year (1.88; 95% CI, 0.64-5.54) and 8-year (1.87; 95% CI, 0.62-5.19) follow-up. At 10-year follow-up survey, the prevalence of IBS was similar for the Shigella -infected cohort and their controls (23.3% versus 19.7%, P = 0.703). Risk factors which were independently associated with PI-IBS among the Shigella -infected cohort included younger age, previous history of functional bowel disorder, and longer duration of diarrhea at baseline. Conclusions Patients who were infected by Shigella sonnei experienced significantly increased risk of IBS until 3 years after shigellosis, and modestly increased risk until 8 years, but showed similar risk of IBS with uninfected controls at 10 years post-infection. PI-IBS is quite a chronic disorder, and follows a long-term natural course.

Background: Clarithromycin, amoxicillin, metronidazole, tetracycline, and levofloxacin have been commonly used for the eradication of Helicobacter pylori. We compared the change in antibiotic resistance of H. pylori strains during two separate periods and investigated the effect of antibiotic resistance on H. pylori eradication. Methods: H. pylori strains were isolated from 71 patients between 2009 and 2010 and from 94 patients between 2011 and 2012. The distribution of minimal inhibitory concentration (MIC) of 5 antibiotics was assessed using the agar dilution method, and H. pylori eradication based on the antimicrobial susceptibility of the isolates was investigated retrospectively. Results: Antibiotic resistance rate against clarithromycin, amoxicillin, tetracycline, metronidazole, and levofloxacin for the 2009-2010 isolates were 7.0% (5/71), 2.8% (2/71), 0% (0/71), 45.1% (32/71), and 26.8% (19/71), respectively, and for the 2011-2012 isolates were 16.0% (15/94), 2.1% (2/94), 0% (0/94), 56.3% (53/94), and 22.3% (21/94), respectively. Multi-drug resistance for 2 or more antibiotics increased slightly from 16.9% (12/71) in the 2009-2010 isolates to 23.4% (22/94) in the 2011-2012 isolates. In followup testing of 66 patients, first-line treatment successfully eradicated H. pylori in 50 patients (75.8%) and failed in 4 of 7 patients (57.1%) in a clarithromycin-resistant and amoxicillin-susceptible group. Conclusions: We observed an increase in resistance to clarithromycin and an overall increase in multi-drug resistance during the 2 study periods. The effectiveness of the eradication regimen was low with combinations of clarithromycin and amoxicillin, particularly in the clarithromycin-resistant group. Thus, eradication of H. pylori depends upon periodic monitoring of antimicrobial susceptibility.

With a dramatic growth in the drone market in recent years, the amount of research efforts dedicated to drones increases correspondingly. However, short battery life severely restricts applications of the unmanned aerial vehicles and has proven to be a hard issue to tackle. Among various solutions for this problem, an automatic drone charging station can be utilized. This paper proposes a fully automatic charging station which operates wirelessly. The station also allows for imprecise landing of the UAV on the platform, which is often the case for practical systems. Application of the proposed charging station may completely eliminate the need in manual battery charging of the quadrotor UAVs.

Background and Aim: The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing in Korea as the dietary pattern and lifestyle become more Westernized and the obese population increases. The spectrum of NAFLD ranges from asymptomatic steatosis to non-alcoholic steatohepatitis (NASH) and cirrhosis. Schwimmer et al. divided NASH into three types according to the histological characteristics, such as adult type, pediatric type and overlap type. We investigated clinical and histologic features of NAFLD patients in Korean young men. Methods: A total of 64 male patients under age 30 years, diagnosed as NAFLD by a liver biopsy, were reviewed retrospectively. NASH was diagnosed by NAFLD activity score (NAS), and NASH patients were classified with Schwimmer's histological classification. Results: Pathological features of liver biopsy revealed NASH in most cases (59 cases, 92.2%) including 29 cases (45.3%) of borderline NASH and 30 cases (46.9%) of definite NASH. The definite NASH group showed significantly high aspartate aminotransferase/alanine aminotransferase levels compared to the borderline NASH group. There were four cases (6.8%) of pediatric type, 17 cases (28.8%) of adult type, and 38 cases (64.4%) of overlap type in the NASH group. NAS was 3.75 ± 0.05 in the pediatric type, 4.29 ± 1.16 in the adult type and 4.87 ± 1.21 in the overlap type, and the overlap type showed a higher NAS than the pediatric type. The fibrosis stage was significantly higher in the overlap type than the other types. Conclusion: Most Korean young men with NAFLD turned out to have borderline or definite NASH. More than half of the NASH cases showed overlap type in Korean young men.

Background Endoscopic papillary large balloon dilatation (EPLBD) after endoscopic sphincterotomy (EST) has recently become widely used for common bile duct (CBD) stone removal, but many clinicians remain concerned about post-procedural pancreatitis with increasing the balloon size to over 15 mm. Aims We aimed to evaluate the safety and efficacy of EPLBD with a relatively large balloon (15–20 mm) after EST and to evaluate the factors related to post-EPLBD pancreatitis. Methods A retrospective review was undertaken of the endoscopic database of 101 patients with CBD stones who underwent EPLBD using a larger balloon size of over 15 mm (15–20 mm). Clinical parameters, endoscopic data, and outcomes were analyzed. Results The mean age of the subjects was 69 years. All patients had a dilated CBD of over 11 mm (mean = 22.6 mm). The mean size of balloon used in EPLBD was 17.1 ± 1.9 mm (range 15–20 mm). Mechanical lithotripsy was required in seven patients (6.9%). The rate of complete stone removal in the first session was 92.1%. Post-procedural pancreatitis developed in five cases (5.4%), but none were graded as severe. The smaller dilatation of the CBD, longer cannulation time, and longer time for stone removal were associated with post-procedural pancreatitis, but larger size of balloon did not affect the development of post-EPLBD pancreatitis. Conclusions EPLBD with a large balloon of over 15 mm with EST is an effective and safe procedure with a very low probability of severe post-procedural pancreatitis. Post-EPLBD pancreatitis was not associated with larger balloon size, but was associated with longer procedure time and smaller dilatation of the CBD.

Purpose Percutaneous radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) has some limitations such as poor sonic window and injury to adjacent organs. The laparoscopic approach has been suggested as an alternative option. The aim of this study was to show the safety and efficacy of laparoscopic RFA for single, small (≤3 cm), and primary or recurrent HCC that is not suitable for percutaneous RFA or surgical resection. Methods We reviewed the cases of 37 patients (32 men and 5 women, mean age 61 ± 8.1 years) who underwent laparoscopic RFA for single, small HCC (≤3 cm) that was unsuitable for percutaneous RFA or surgical resection. Results The technical success rate was 94.6% and 34 patients (95%) had no complications. There were no conversions to open RFA and no operative mortality. The primary effectiveness rate 1 month after the procedure was 100%. The overall recurrence rates at 3, 6, 12, and 24 months after the laparoscopic RFA were 8.1%, 14.4%, 25%, and 35.7%, respectively. The local tumor progression rate was 4.2% at 6 months and 8.7% at 9 months. Conclusion Laparoscopic RFA is a safe and effective treatment for HCC cases that are unsuitable for percutaneous RFA.

CCR7 and its ligand, CCL21, are known to establish microenvironments for the initiation of immune responses in secondary lymphoid tissue. It has also been reported that CCR7 ligand gene-deleted mice have defects in lymphocyte homing. In addition, the injection of the CCR7 ligand was shown to induce the expression of memory T cells. In this study, we analyzed the expression of CCR7 and its ligand in HSV-induced Behcet's disease (BD)-like inflammation of mice. Additionally, plasmids containing the CCR7 ligand CCL19 or CCL21, pcDNA3.1-CCL19 or pcDNA3.1-CCL21, respectively, were injected into symptomatic mice, and changes in the population of memory T cells were determined. After administration of pcDNA3.1-CCL21, the frequencies of CD8+CD44+, CD8+CD62L− memory T cells were significantly up-regulated and the symptoms were not deteriorated when compared to the control vector injected group. Specifically, the difference in frequencies of CCR7+ peripheral blood mononuclear cells between active BD patients and inactive BD patients was similar to that of HSV-induced BD-like mice. These results suggest that CCR7, its ligand, and CD8+ memory cells are correlated with the regulation of BD symptoms.

Background/Aims: We aimed to determine the concordance rate and clinical predictors of eosinophilic esophagitis (EoE) in patients with endoscopically suspected eosinophilic esophagitis (ESEoE) findings. Methods: From June 2006 to December 2009 in Gangnam Severance Hospital, we prospectively enrolled the patients of “endoscopically suspected eosinophilic esophagitis (ESEoE)”, and then we retrospectively reviewed and analyzed clinical features and endoscopic findings. Results: We found 17 patients of ESEoE, and 5 of them were finally confirmed as an EoE by histology (diagnostic concordance rate 29.4%). We added two more patients previously diagnosed as EoE and compared patients of EoE＋ (n=7) with EoE− (n=12). Mean age was 56.0 (range 36-70) and 51.0 (range 36-68) years old, respectively. In EoE＋ group, there were 5 males and 2 females and 6 males and 6 females in EoE- group. The symptoms of EoE＋ patients were dysphagia (n=5), food impaction (n=3), foreign body sensation in esophagus (n=2), chest pain (n=1), and heartburn (n=1). EoE− patients complained food impaction (n=5), heartburn (n=4), chest pain (n=2), foreign body sensation in esophagus (n=2), and dysphagia (n=1). The endoscopic findings of EoE＋ patients were furrows (n=6), rings (n=5), exudates or nodules (n=3), and friability (n=1). EoE− patients showed rings (n=10) and furrows(n=7). Univariative analysis showed that ‘a symptom of dysphagia’, ‘presence of exudates or nodules’, ‘more than 2 suggestive endoscopic findings’ were significantly different between two groups. Conclusions: In ESEoE, diagnostic concordance rate was 29.4%. In addition, ‘symptom of dysphagia’, ‘exudates or nodules’, ‘≥2 endoscopic findings’ are more suggestive of EoE in ESEoE

Irritable bowel syndrome (IBS) patients frequently complain of gas-related symptoms, and the lactulose breath test (LBT) is a test that assesses the amount of fermented gas generated by bacteria in the bowel. We aimed to assess the relationship among intestinal gas volume, LBT result, and gastrointestinal symptom score in healthy control and functional bowel disorder (FBD) subjects. In 84 IBS subjects, 24 FBD subjects other than IBS, and 25 healthy controls, a symptom questionnaire that enquired about seven main symptoms, plain abdominal radiography and a LBT were checked on the same day. The intestinal gas volume was calculated as the gas volume score (GVS) with a digitalized image of plain supine abdominal radiographs. The GVS was greater in the LBT (+) group compared to the LBT (−) group (P = 0.02). The GVS was greater in the FBD and IBS groups than in the control group (P

PURPOSE Itopride hydrochloride (itopride) inhibits acetylcholinesterase (AChE) and antagonizes dopamine D(2) receptor, and has been used as a gastroprokinetic agent. However, its prokinetic effect on the small bowel or colon has not yet been thoroughly investigated. The aim of this study was to investigate the effects of itopride on motor functions of the ileum and colon in guinea pigs. MATERIALS AND METHODS The distal ileum was excised and the activity of peristaltic contraction was determined by measuring the amplitude and propagation velocity of peristaltic contraction. The distal colon was removed and connected to the chamber containing Krebs-Henseleit solution (K-H solution). Artificial fecal matter was inserted into the oral side of the lumen, and moved toward the anal side by intraluminal perfusion via peristaltic pump. Colonic transit times were measured by the time required for the artificial feces to move a total length of 10 cm with 2-cm intervals. RESULTS In the ileum, itopride accelerated peristaltic velocity at higher dosage (10(-10)-10(-6) M) whereas neostigmine accelerated it only with a lower dosage (10(-10)-10(-9) M). Dopamine (10(-8) M) decelerated the velocity that was recovered by itopride infusion. Itopride and neostigmine significantly shortened colonic transit at a higher dosage (10(-10)-10(-6) M). Dopamine (10(-8) M) delayed colonic transit time that was also recovered after infusion of itopride. CONCLUSION Itopride has prokinetic effects on both the ileum and colon, which are regulated through inhibitory effects on AChE and antagonistic effects on dopamine D(2) receptor.

3 , Wonju, Korea Background/Aims: This study aims to identify the gene mutation pattern associated with antibiotic resistance for mainly used anti- biotics in Helicobacter pylori strains isolated from Koreans. Materials and Methods: Seventy-one H. pylori strains were isolated from gastric mucosal biopsy specimens. The specimens were cultivated and the resistance to 5 antibiotics were assessed by using agar gel dilution method. DNA sequencing was carried out to detect the resistance-related gene mutations. Results: A point mutation at A2143G of 23S rRNA was observed in all of the clarithromycin resistant strains, but tetracycline re- sistant strains were not found. Substitution N562Y in penicillin binding protein 1 were observed in an amoxicillin resistant strain (minimum inhibitory concentration (MIC) 2.0μg/mL). Eleven (57.8%) out of 19 levofloxacin resistant strains showed amino acid substitution at N87K (8 strains), N87I, A88V and D91N in GyrA. The truncation in rdxA was detected in 8 (25.0%) out of 32 metro- nidazole resistant strains. Two out of the 7 patients who failed in first-line treatment of clarithromycin and amoxicillin showed A2143G mutation. Conclusions: 23S rRNA mutation is closely related to the failure of eradication, however, the fact that five people who have no gene mutation failed eradication implies that other factors are related. As MIC levels in clarithromycin and levofloxacin resistance strains are getting higher, their appropriate gene mutation is more correlated. (Korean J Helicobacter Up Gastrointest Res 2014;14:95-102)

To evaluate the effect of prokinetic drugs on electrogastrography (EGG) parameters according to symptomatic changes in patients with functional dyspepsia (FD).Seventy-four patients with FD were prospectively enrolled in this study between December 2006 and December 2010. We surveyed the patients using a questionnaire on dyspeptic symptoms before and after an 8-wk course of prokinetic drug treatment. We also measured cutaneous pre-prandial and post-prandial EGG recordings including percentage of gastric waves (normogastria, bradygastria, tachygastria), dominant frequency (DF), dominant power (DP), dominant frequency instability coefficient (DFIC), dominant power instability coefficient (DPIC), and the ratio of post-prandial to fasting in DP before and after the 8-wk course of prokinetic drug treatment.Fifty-two patients (70%) achieved symptomatic improvement after prokinetic drug treatment. Patients who had normal gastric slow waves showed symptom improvement group after treatment. Post-prandial DF showed a downward trend in the symptom improvement group, especially in the itopride group. Post-prandial DP was increased regardless of symptom improvement, especially in the itopride group and mosapride group. Post-prandial DFIC and DPIC in the symptom improvement group were significantly increased after the treatment. The EGG power ratio was increased after treatment in the symptom improvement group (0.50 ± 0.70 vs 0.93 ± 1.77, P = 0.002), especially in the itopride and levosulpiride groups.Prokinetics could improve the symptoms of FD by regulating gastric myoelectrical activity, and EGG could be a useful tool in evaluating the effects of various prokinetics.

Postoperative nausea and vomiting (PONV) is considered as a main cause of dissatisfaction after surgery with postoperative pain. Overall incidence of PONV is 30%, and the incidence rate can increase up to 70-80% in high-risk patient groups. The causes of PONV are multifactorial and can largely be categorized as patient risk factors, surgical procedure, and anaesthetic technique. Pharmacological treatments including dopamine antagonist, anti-histamines, anticholinergics, dexamethasone, neurokinin-1 antagonists, and serotonin antagonist are used to prevent and treat PONV. This article reviews the prevalence, mechanisms, and risk factors of PONV, and how to prevent and treat it. (Korean J Med 2012;82:537-542)

Due to their novel properties, GaN based semiconductors and their nanostructures are promising components in a wide range of nanoscale device applications. In this work, the gallium nitride is deposited on c-axis oriented sapphire and porous SWCNT substrates by molecular beam epitaxy using a novel single source precursor of with ammonia as an additional source of nitrogen. The advantage of using a single molecular precursor is possible deposition at low substrate temperature with good crystal quality. The deposition is carried out in a substrate temperature range of 600-750. The microstructural, structural, and optical properties of the samples were analyzed by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and photoluminescence. The results show that substrate oriented columnar-like morphology is obtained on the sapphire substrate while sword-like GaN nanorods are obtained on porous SWCNT substrates with rough facets. The crystallinity and surface morphology of the deposited GaN were influenced significantly by deposition temperature and the nature of the substrate used. The growth mechanism of GaN on sapphire as well as porous SWCNT substrates is discussed briefly.

Hybridization of semiconductor materials with carbon nanotubes (CNTs) is a recent field of interest in which new nanodevice fabrication and applications are expected. In this work, nanowire type GaAs structures are synthesized on porous single-wall carbon nanotubes (SWCNTs) as templates using the molecular beam epitaxy (MBE) technique. The field emission properties of the as-synthesized products were investigated to suggest their potential applications as cold electron sources, as well. The SWCNT template was synthesized by the arc-discharge method. SWCNT samples were heat-treated at under an atmosphere to remove amorphous carbon. After heat treatment, GaAs was grown on the SWCNT template. The growth conditions of the GaAs in the MBE system were set by changing the growth temperatures from to . The morphology of the GaAs synthesized on the SWCNTs strongly depends on the substrate temperature. Namely, nano-crystalline beads of GaAs are formed on the CNTs under , while nanowire structures begin to form on the beads above . The crystal qualities of GaAs and SWCNT were examined by X-ray diffraction and Raman spectra. The field emission properties of the synthesized GaAs nanowires were also investigated and a low turn-on field of was achieved. But, the turn-on field was increased in the second and third measurements. It is thought that arsenic atoms were evaporated during the measurement of the field emission.