Search

Background/Aims: This study aimed to review the indications, methods, cooperation, complications, and outcomes of percutaneous endoscopic gastrostomy (PEG). Methods: Questionnaires were sent to 200 hospitals, of which 62 returned their questionnaires, with a response rate of approximately 30%. Descriptive statistics were calculated to analyze the responses to the questionnaires. Results: In 2019, a total of 1,052 PEGs were performed in 1,017 patients at 62 hospitals. The main group who underwent PEG was older adult patients with brain disease, particularly stroke. Nutritional supply was an important purpose of the PEG procedure. “The pull method” was the most commonly used for initial PEG insertion. The complications related to PEG were mostly mild, with leakage being the most common. Patients who underwent PEG procedures were primarily educated regarding the post-procedure management and complications related to PEG. Preoperative meetings were skipped at >50% of the institutions. Regarding the cooperation between the nutrition support team (NST) and the physician performing PEG, few endoscopists answered that they cooperated with NST before and after PEG. Moreover, the rate of NST certification obtained by physicians performing PEG and the frequency of attendance at NST-related conferences were relatively low. Conclusions: This study shows a similar trend to that found in the previous PEG guidelines. However, it covers new aspects, including team-based work for PEG procedure, nutrition support, and education for patients and guardians. Therefore, each medical institution needs to select an appropriate method considering the medical environment and doctor’s abilities.

Abstract Epstein–Barr virus (EBV)-associated gastric cancer (EBVaGC) is a distinct molecular subtype of gastric cancer. This study aims to investigate genomic and clinicopathological characteristics of EBVaGC according to the histological pattern. We retrospectively collected 18 specimens of surgically resected EBVaGCs. Whole-exome sequencing was performed for all cases. Moreover, PD-L1 expression and tumor-infiltrating lymphocyte (TIL) percentage were investigated. Among 18 EBVaGCs, 10 cases were of intestinal histology, 3 were of poorly cohesive histology, and the remaining 5 were of gastric carcinoma with lymphoid stroma histology. Whole-exome sequencing revealed that EBVaGCs with intestinal histology harbored pathogenic mutations known to frequently occur in tubular or papillary adenocarcinoma, including TP53, KRAS, FBXW7, MUC6, ERBB2, CTNNB1, and ERBB2 amplifications. One patient with poorly cohesive carcinoma histology harbored a CDH1 mutation. Patients with EBVaGCs with intestinal or poorly cohesive carcinoma histology frequently harbored driver mutations other than PIK3CA, whereas those with EBVaGCs with gastric carcinoma with lymphoid stroma histology lacked other driver mutations. Moreover, the histological pattern of EBVaGCs was significantly associated with the levels of TILs (P = 0.005) and combined positive score (P = 0.027). In conclusion, patients with EBVaGCs with different histological patterns exhibited distinct genetic alteration, PD-L1 expression, and degree of TILs.

Background/Aims This study aimed to evaluate the characteristics of endoscopic retrograde cholangiopancreatography (ERCP) or endoscopic ultrasonography (EUS)-related adverse events (AEs) that eventually lead to medical disputes or claims on medical professional liability. Methods Medical disputes for ERCP/EUS-related AEs filed in the Korea Medical Dispute Mediation and Arbitration Agency between April 2012 and August 2020 were evaluated using corresponding medical records. AEs were categorized into three sections: procedure-related, sedation-related, and safety-related AEs. Results Among a total of 34 cases, procedure-related AEs were 26 (76.5%; 12 duodenal perforations, 7 post-ERCP pancreatitis, 5 bleedings, 2 perforations combined with post-ERCP pancreatitis); sedation-related AEs were 5 (14.7%; 4 cardiac arrests, 1 desaturation), and safety-related AEs were 5 (8.8%; 1 follow-up loss for stent removal, 1 asphyxia, 1 fall). Regarding clinical outcomes, 20 (58.8%) were fatal and eventually succumbed to AEs. For the types of medical institutions, 21 cases (61.8%) occurred at tertiary or academic hospitals, and 13 (38.2%) occurred at community hospitals. Conclusions The ERCP/EUS-related AEs filed in Korea Medical Dispute Mediation and Arbitration Agency showed distinct features: duodenal perforation was the most frequent AE, and clinical outcomes were fatal, resulting in at least more than permanent physical impairment.

Background/Aims Tegoprazan, a novel potassium-competitive acid blocker, has shown rapid action and gastric acid inhibition. In this study, we evaluated the efficacy of a tegoprazan-based, nonbismuth-containing quadruple (concomitant) therapy for the primary eradication of Helicobacter pylori. Methods We conducted a prospective, single-arm, single-center, primitive study to verify the efficacy of a 10-day tegoprazan-based (50-mg dose) concomitant therapy, including amoxicillin (1,000-mg dose), clarithromycin (CLA; 500-mg dose), and metronidazole (MET; 500-mg dose) twice daily as a first-line treatment for H. pylori eradication. Results We tested consecutive cultures for antibiotic susceptibility and minimum inhibitory concentrations. We enrolled 84 participants; 79 (94.0%) completed first-line therapy. The overall intention-to-treat and per-protocol eradication rates were 90.5% (95% confidence interval [CI], 82.1–95.8) and 96.2% (95% CI, 83.4–97.6), respectively. Of the 73 participants evaluated for antibiotic resistance, 19 (26.0%), 32 (42.5%), and 8 (11.0%) exhibited CLA, MET, and CLA and MET dual resistance, respectively. Of these, 39 participants (66.1%) exhibited successful eradication after the therapeutic regimen despite antibiotic resistance. Conclusions The 10-day tegoprazan-based concomitant therapy may be an effective first-line treatment for eradicating H. pylori.

Background/Aims Endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) is integral to the diagnosis of gastrointestinal (GI) subepithelial tumors (SETs). The impact of different EUS-FNB tissue sampling techniques on specimen adequacy and diagnostic accuracy in SETs has not been fully evaluated. This study aimed to compare the diagnostic outcomes of slow-pull (SP) and standard suction (SS) in patients with GI SETs. Methods In this retrospective comparative study, 54 patients were enrolled. Medical records were reviewed for location and size of the target lesion, FNB needle type/size, technical order, specimen adequacy, diagnostic yield, and adverse events. The acquisition rate of adequate specimens and diagnostic accuracy were compared according to EUS-FNB techniques. Results The mean lesion size was 42.6±36.4 mm, and most patients were diagnosed with GI stromal tumor (75.9%). The overall diagnostic accuracies of the SP and SS techniques were 83.3% and 81.5%, respectively (p=0.800). The rates of obtaining adequate core tissue were 79.6% and 75.9%, respectively (p=0.799). No significant clinical factors affected the rate of obtaining adequate core tissue, including lesion location and size, FNB needle size, and final diagnosis. Conclusions SP and SS had comparable diagnostic accuracies and adequate core tissue acquisition for GI SETs via EUS-FNB.

Cases of foreign body ingestion are frequently seen in gastroenterology. However, it is not common for the foreign body to be located in the submucosa, which obscures it from view, even during endoscopy. A 74-year-old woman visited the emergency room 10 days after swallowing an implant screw during an implant procedure at a dental clinic. Abdominal CT revealed a 14-mm-long radio-opaque screw in the posterior wall of the proximal body of the stomach. On endoscopy, the screw was not observed in the stomach; however, fluoroscopic examination revealed that it was located under the mucosa of the posterior wall of the proximal body of the stomach. The screw was grasped using alligator forceps and retrieved. There was no evidence of perforation on chest radiography. Herein, we present a case wherein a foreign body embedded under the mucosa was removed.

Background/Aims: Dietary factors can aggravate the symptoms of irritable bowel syndrome (IBS). Many IBS patients try restrictive diets to relieve their symptoms, but the types of diets with an exacerbating factor are unknown. Therefore, this paper reports the results of a systematic review and network meta-analysis of randomized-controlled trials (RCTs) reviewing the efficacy of food restriction diets in IBS. Methods: The MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Clinicaltrials.gov databases were searched until July 21, 2021, to retrieve RCTs assessing the efficacy of restriction diets in adults with IBS. Two independent reviewers performed the eligibility assessment and data abstraction. RCTs that evaluated a restriction diet versus a control diet and assessed the improvement in global IBS symptoms were included. These trials reported a dichotomous assessment of the overall response to therapy. Results: A total of 1,949 citations were identified. After full-text screening, 14 RCTs were considered eligible for the systematic review and network meta-analysis. A starch- and sucrose-reduced diet and a diet with low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) showed significantly better results than a usual diet. Symptom flare-ups in patients on a gluten- free diet were also significantly lower than in those on high-gluten diets. Conclusions: These findings showed that the starch- and sucrose-reduced, low FODMAP, and gluten-free diets had superior effects in reducing IBS symptoms. Further studies, including head-to-head trials will be needed to establish the effectiveness of dietary restrictions on IBS symptoms.

Background/Aims: After esophagogastroduodenoscopy (EGD) with biopsy, some patients experience gastrointestinal symptoms. This study investigated the effect of sodium alginate on biopsy-related gastrointestinal symptoms. Methods: In this open-label, randomized, controlled trial, patients undergoing EGD with biopsy were randomly assigned to a treatment or control group. In the treatment group, sodium alginate was orally administered for 3 days after EGD. Patients completed questionnaires about their gastrointestinal symptoms at baseline (past week), the day after returning home, and after another 3 days. Gastrointestinal symptoms, including abdominal pain, epigastric pain/soreness, heartburn, acid reflux, nausea/vomiting, borborygmus, abdominal distension, and belching, were rated using an upper gastrointestinal symptom rating scale (GSRS). Results: A total of 210 persons (138 men) who underwent EGD with biopsy were enrolled and allocated to the treatment (n=104) or control (n=106) group. At baseline, the demographic factors and GSRS scores were not different between the control and treatment groups. The epigastric pain/soreness score increased in the control group after endoscopic biopsy (+0.056), whereas the score was decreased in the treatment group (–0.067) (p=0.042). In the treatment group, the scores for acid regurgitation and epigastric soreness decreased during follow-up from those at baseline (p

Background/Aims To date, no reports have compared the diagnostic efficacy of narrow-band imaging (NBI) and i-scan for the histologic prediction of intermediate-to-large colorectal polyps. We aimed to compare the diagnostic accuracy of NBI and i-scan in predicting histology, and their inter-/intra-observer agreement. Methods We performed a prospective, randomized study that included 66 patients (NBI, n=33 vs. i-scan, n=33) with colorectal polyps (size >10 mm but

Background/Aims: Several clinical factors have been used to predict the response for concurrent chemoradiotherapy (CCRT); however, these factors are insufficient for prognostic predictions. We investigated clinical factors to assess whether they could be used to predict the response to CCRT and the survival of patients with esophageal cancer. Methods: Patients with esophageal cancer underwent CCRT from January 2005 to December 2015. Response to CCRT was classified as progressive disease (PD), stationary disease (SD), partial remission (PR), or complete remission (CR). Factors to predict the response to CCRT and patient survival were subsequently investigated. Results: A total of 535 esophageal cancer patients underwent CCRT. Four hundred ninety-three patients were followed up, and patient outcomes were investigated. In the adjusted analysis, patients with advanced stage disease (relative risk [RR], 0.28 in stage III and 0.12 in stage IV compared to stage I), poor performance status, circumferential involvement (RR, 0.61), and male sex (RR, 0.31) were less likely to achieve CR. Advanced stage disease (hazard ratio [HR], 1.71 in stage III/IV), poor CCRT response (HR, 2.82 in PR, 4.47 in SD, 4.77 in PD compared to CR), and poor performance status (HR, 1.38 in ECOG 2-4) were found to increase mortality. Conclusions: Advanced stage disease, poor performance status, male sex, and circumferential involvement were independent predictive factors for a poor response to CCRT. Advanced stage, poor performance status, and poor CCRT response were independent factors for decreased survival.

Background/Aims The Internet is the main resource for health-related information. The incidence of inflammatory bowel disease (IBD) is rapidly increasing in Asian countries. However, the quality of websites for IBD available in this region has not been evaluated. We aimed to evaluate the quality of the information on IBD obtained from Korean websites. Methods Using the terms “Crohn’s disease” or “ulcerative colitis,” websites were selected from those obtained with the three most renowned search engines in Korea; 60 websites from the results of each engine were chosen. The websites were classified into institutional, commercial, charitable, supportive, or alternative medicine types according to the characteristics of each site. The websites were evaluated regarding content quality using the validated DISCERN instrument and the Journal of the American Medical Association benchmarks. Results The median score of all the websites according to the DISCERN instrument was 32 (interquartile range, 25 to 47) out of 80, indicating an insufficient overall quality of information. The alternative medicine sites scored the lowest, whereas the institutional sites scored the highest (p < 0.05). The quality of information was significantly different among the search engines (p = 0.028). The rank of appearance in the Google search result did not correlate with the quality level of the information. Conclusions The quality of information on the Internet regarding IBD varied according to the website type and search engine. Accreditation and quality assurance systems should be implemented for websites to ensure that the public and patients obtain accurate information on IBD.

Endoscopic submucosal dissection (ESD) is widely used for the treatment of colorectal neoplasia in patients who are candidates for endoscopic resection. In particular, pyogenic liver abscess (PLA), although rare, can occur. To our knowledge, there are no reports of PLA cases after ESD. Therefore, we report a rare case of PLA caused by ESD. A 76-year-old man was referred from a local clinic and admitted to our hospital for colonic ESD for a large polypoid mass. During colonoscopy, a 5-cm mass was seen in the cecum. ESD was performed. Four days after the procedure, he complained of myalgia and abdominal discomfort. Computed tomography revealed a 5.4-cm PLA in the medial segments of the liver. He was treated with antibiotics, and a percutaneous drainage catheter was inserted. Here, we report a very rare complication (PLA) after ESD. In conclusion, comprehensive awareness of the development of PLA is needed in ESD cases.

Background/Aims The validity of 13C-urea breath test (13C-UBT) for Helicobacter pylori detection is influenced by atrophic gastritis. The aim of this study was to evaluate the effect of citric acid on the accuracy of 13C-Urea breath test after H. pylori eradication therapy in a region where atrophic gastritis is common. Methods : In this prospective study, H. pylori-positive patients received 13C-UBT after H. pylori eradication regimen. They were classified into citric acid group and control group. To determine diagnostic accuracy of 13C-UBT, patients were offered invasive methods. Results : A total of 1,207 who successfully took H. pylori-eradication regimen received UBT. They were assigned into the citric acid group (n=562) and the control group (n=645). The mean 13C-UBT value of the citric acid group was 10.3±26.4‰, which was significantly (p

Background/Aims Contrast-enhanced harmonic endoscopic ultrasonography (CEH-EUS) is a promising imaging modality that can differentiate subepithelial tumors (SETs) by detecting the degree of enhancement. However, whether CEH-EUS alone can predict the malignancy risk of gastrointestinal stromal tumors (GISTs) remains unclear. This study aimed to evaluate the feasibility of CEH-EUS by using perfusion analysis software for distinguishing among SETs and predicting the malignancy risk of GISTs. Methods : We retrospectively included patients with SETs who underwent preoperative CEH-EUS. In this study, 44 patients with histologically proven GISTs and benign SETs were enrolled. Perfusion analysis was performed using perfusion quantification software. Peak enhancement (PE), wash-in rate (WiR), wash-in perfusion index (WiPI), and wash-in and wash-out areas under the time-intensity curve (WiWoAUC) were calculated and compared between the GISTs and benign SETs. Results : When we allocated the enrolled patients into the leiomyoma group and low- and high-grade malignancy GIST groups, significant statistical differences in PE (p

Endoscopic resection (ER) is the current standard of care for selected cases of gastric epithelial dysplasia or early gastric cancer because of its curative en bloc resectability and complete histopathological assessment of the specimen. Although ER provides many advantages to surgery, some adverse events, such as bleeding, perforation, and local recurrence, can occur during and after the procedure. Furthermore, negative pathological findings after ER cause concerns about the adequacy of the procedure and local recurrence after ER among endoscopists and patients. Several variant factors, such as complete removal of small gastric tumor lesions by using initial forceps biopsy, pathological inconsistencies between pathologists, and performing ER in the wrong area. Thus, endoscopists must consider these risk factors to avoid and manage negative pathological results.

Background/Aims: Recently, the eradication rate of Helicobacter pylori (H. pylori) infection has decreased to less than 80% worldwide with the use of clarithromycin-based triple therapy owing to the increased resistance of H. pylori to antibiotics, especially clarithromycin and metronidazole. This prospective study aimed to determine eradication rate of H. pylori following high and frequent doses of extended-release dexlansoprazole and amoxicillin, as a dual therapy in a region with high clarithromycin resistance rate. Methods: A total of 50 treatment-naïve patients with active H. pylori infections, who were confirmed through via rapid urease test or histology and serology between November 2015 and February 2016 at our hospital, were included for analysis. All enrolled patients were treated with 750 mg amoxicillin and 30 mg dexlansoprazole, four times a day for a total duration of 14 days. Treatment success was determined using urea breath test four weeks after treatment completion. Results: Seven out of the 50 patients (29 men and 21 women; mean age, 57 years) dropped out during the study. The total eradication rate was 52% (26/50), and that for those with a compliance rate of over 90% was 68.4% (26/38). H. pylori infections were not successfully eradicated in patients with a compliance rate of less than 90%. Nine patients (18%) reported side effects, such as mild diarrhea and abdominal fullness. No significant factors, such as smoking and alcohol consumption, affected the infection the eradication rate. Conclusions: High and frequent doses of proton pump inhibitor–amoxicillin dual therapy were not effective in eradicating H. pylori infection in a province with high clarithromycin resistance rate.

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder. The pathophysiology of IBS is not completely understood. Genetic, immune, environmental, inflammatory, neurological and psychological factors contribute to the risk of this condition. Traditional research explored gastrointestinal motor abnormalities, central neural dysregulation, abnormal psychological features, and visceral hypersensitivity. More recent investigations consider bacterial overgrowth, abnormal serotonin pathways, altered gut flora, immune activation and mucosal inflammation. The purpose of this article is to review recent translational research concerning the pathophysiology, biomarker and genetic factors of IBS and to encourage IBS research in Korea. (Korean J Gastroenterol 2016;68:138-142)

Objective. The serum pepsinogen test has limitation in its predictive power as a noninvasive biomarker for gastric cancer screening. We aimed to investigate whether the combination of TFF3 and pepsinogen could be an effective biomarker for the detection of gastric cancer even in the early stages. Methods. In total, 281 patients with early gastric cancer (EGC), who underwent endoscopic submucosal dissection in Korea, and 708 healthy individuals from Japan were enrolled in the derivation cohort. The validation cohort included 30 Korean patients with EGC and 30 Korean healthy control blood donors. Serum TFF3 levels were examined using enzyme-linked immunosorbent assay. Results. Using a cutoff of 6.73 ng/mL in the derivation cohort, the sensitivity of the combination of tests for EGC detection was superior (87.5%) to that of TFF3 (80.4%) or pepsinogen test alone (39.5%). Similarly, in the validation cohort, the sensitivity of TFF3 plus pepsinogen was higher (90.4%) than that of TFF3 (80.0%) or pepsinogen test alone (33.3%). Conclusion. The combination of serum TFF3 and pepsinogen is a more effective noninvasive biomarker for gastric cancer detection compared with pepsinogen or TFF3 alone, even in EGC. This trial is registered with NCT03046745.

The gastric accommodation reflex is an important mechanism in gastric physiology. However, the aging-associated structural and functional changes in gastric relaxation have not yet been established. Thus, we evaluated the molecular changes of interstitial cell of Cajal (ICC) and neuronal nitric oxide synthase (nNOS) and the function changes in the corpus of F344 rats at different ages (6-, 31-, 74-wk and 2-yr). The proportion of the c-Kit-positive area in the submucosal border (SMB) and myenteric plexus (MP) layer was significantly lower in the older rats, as indicated by immunohistochemistry. The density of the nNOS-positive immunoreactive area also decreased with age in the SMB, circular muscle (CM), and MP. Similarly, the percent of nNOS-positive neuronal cells per total neuronal cells and the proportion of nNOS immunoreactive area of MP also decreased in aged rats. In addition, the mRNA and protein expression of c-Kit and nNOS significantly decreased with age. Expression of stem cell factor (SCF) and the pan-neuronal marker PGP 9.5 mRNA was significantly lower in the older rats than in the younger rats. Barostat studies showed no difference depending on age. Instead, the change of volume was significantly decreased by L-NG63-nitroarginine methyl ester in the 2-yr-old rats compared with the 6-wk-old rats (P = 0.003). Taken together, the quantitative and molecular nNOS changes in the stomach might play a role in the decrease of gastric accommodation with age.

[This corrects the article DOI: 10.1371/journal.pone.0169113.].

Background/Aims Non-celiac gluten sensitivity is characterized by intestinal and extra intestinal symptoms associated with the consumption of glutencontaining food. Since biomarkers for non-celiac gluten sensitivity are lacking, its prevalence is estimated based on self-reported symptoms. However, no data exist on self-reported non-celiac gluten sensitivity in the Korean population. Thus, we aim to investigate the prevalence of self-reported non-celiac gluten sensitivity in the Korean population and to determine its demographic and clinical characteristics. Methods This study surveyed Korean participants aged 18-80 years who visited gastroenterology outpatient clinics at 9 tertiary hospitals in South Korea from January 2016 to February 2017. They were questioned regarding symptoms related to gluten ingestion: degree of discomfort (visual analog scale score), frequency, time of symptom onset, and duration. Abdominal discomfort caused by 11 different kinds of gluten-containing Korean food items was investigated. Results More non-celiac gluten sensitivity self-reporters were identified among those with irritable bowel syndrome (33.6%) than among controls (5.8%). Major gastrointestinal symptoms included bloating (75.0%), abdominal discomfort (71.3%), and belching (45.0%). Common extra-intestinal symptoms included fatigue (20.0%) and headache (13.7%). More than half of those who self-reported nonceliac gluten sensitivity (66.3%) developed symptoms within 1 hour of food ingestion, and symptoms were localized in the upper abdomen (37.5%) and entire abdomen (30.0%). Conclusion Our findings suggest that if there are gluten-related symptoms in irritable bowel syndrome, the possibility of accompanying non-celiac gluten sensitivity should be considered. [ABSTRACT FROM AUTHOR]

Background/Aims: The validity of 13C-urea breath test (13C-UBT) for Helicobacter pylori detection is influenced by atrophic gastritis. The aim of this study was to evaluate the effect of citric acid on the accuracy of 13C-Urea breath test after H. pylori eradication therapy in a region where atrophic gastritis is common. Methods: In this prospective study, H. pylori-positive patients received 13C-UBT after H. pylori eradication regimen. They were classified into citric acid group and control group. To determine diagnostic accuracy of 13CUBT, patients were offered invasive methods. Results: A total of 1,207 who successfully took H. pylori -eradication regimen received UBT. They were assigned into the citric acid group (n=562) and the control group (n=645). The mean 13CUBT value of the citric acid group was 10.3±26.4%, which was significantly (p<0.001) higher than that of that control group (5.1%±12.6%). Of these patients 122 patients were evaluated by endoscopic biopsy methods. Based on invasive tests, the accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 13C-UBT for the citric acid group were 83.3%, 91.7%, 81.3%, 55.0%, and 97.5%, respectively. Those of the control group were 87.7%, 90.9%, 88.2%, 62.5%, and 97.8%, respectively. They were not significantly different between the two groups. Although the presence of gastric atrophy and intestinal metaplasia (IM) decreased the accuracy, the decrease was not significant. Conclusions: In a country with high prevalence of atrophic gastritis or IM, false positivity remained common despite the use of citric acid in 13C-UBT. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

We present a cost-effective dual polarization quadrature phase-shift coherent receiver module using a silica planar lightwave circuit (PLC) hybrid assembly. Two polarization beam splitters and two 90° optical hybrids are monolithically integrated in one silica PLC chip with an index contrast of 2%-Δ. Two four-channel spot-size converter integrated waveguide-photodetector (PD) arrays are bonded on PD carriers for transverse-electric/ transverse-magnetic polarization, and butt-coupled to a polished facet of the PLC using a simple chip-to-chip bonding method. Instead of a ceramic sub-mount, a lowcost printed circuit board is applied in the module. A stepped CuW block is used to dissipate the heat generated from trans-impedance amplifiers and to vertically align RF transmission lines. The fabricated coherent receiver shows a 3-dB bandwidth of 26 GHz and a common mode rejection ratio of 16 dB at 22 GHz for a local oscillator optical input. A bit error rate of 8.3 × 10-11 is achieved at a 112-Gbps back-to-back transmission with off-line digital signal processing. [ABSTRACT FROM AUTHOR]

This paper demonstrates the effect of fluoride-based plasma treatment on the performance of Al2O3/AlGaN/ GaN metal-insulator-semiconductor heterostructure field effect transistors (MISHFETs) with a T-shaped gate length of 0.20 μm. For the fabrication of the MISHFET, an Al2O3 layer as a gate dielectric was deposited using atomic layer deposition, which greatly decreases the gate leakage current, followed by the deposition of the silicon nitride layer. The silicon nitride layer on the gate foot region was then selectively removed through a reactive ion etching technique using CF4 plasma. The etching process was continued for a longer period of time even after the complete removal of the silicon nitride layer to expose the Al2O3 gate dielectric layer to the plasma environment. The thickness of the Al2O3 gate dielectric layer was slowly reduced during the plasma exposure. Through this plasma treatment, the device exhibited a threshold voltage shift of 3.1 V in the positive direction, an increase of 50 mS/mm in trans conductance, a degraded off-state performance and a larger gate leakage current compared with that of the reference device without a plasma treatment. [ABSTRACT FROM AUTHOR]

Background/Aims: Controversy exists regarding the characteristics of Helicobacter pylori infection-negative gastric cancer (HPIN-GC). The aim of this study was to evaluate clinicopathologic features of HPIN-GC compared to H. pylori infection-positive gastric cancer (HPIP-GC) using a comprehensive analysis that included genetic and environmental factors. Methods: H. pylori infection status of 705 resectable gastric cancer patients was determined by the rapid urease test, testing for anti-H. pylori antibodies, histologic analysis and culture of gastric cancer tissue samples, and history of H. pylori eradication. HPIN-GC was defined as gastric cancer that was negative for H. pylori infection based on all five methods and that had no evidence of atrophy in histology or serology. Results: The prevalence of HPIN-GC was 4% (28/705). No significant differences with respect to age, sex, smoking, drinking, family history of gastric cancer or obesity were observed between the two groups. HPIN-GC tumors were marginally more likely to involve the cardia (14.3% for HPIN-GC vs 5.3% for HPIP-GC, p=0.068). The Lauren classification, histology, and TNM stage did not differ according to H. pylori infection status. Microsatellite instability was not different between the two groups, but p53 overexpression in HPIN-GC was marginally higher than in HPIP-GC (56.0% for HPIN-GC vs 37.0% for HPIP-GC, p=0.055). Conclusions: The prevalence of HPIN-GC was extremely low, and its clinicopathologic characteristics were similar to HPIP-GC. [ABSTRACT FROM AUTHOR]

Candida is a rare cause of infectious arthritis, and it can be found in infants and immunocompromised patients. Patients with maintenance hemodialysis are prone to opportunistic infections because of altered immunity, and frequent exposures to health-care associated infections. Herein, we report a case of candida arthritis of right shoulder with preceding fungemia in patients with maintenance hemodialysis. The diagnosis is based on the isolation of Candida Tropicalis from blood and synovial fluids of the shoulder joint. The patient has received intravenous fluconazole and arthroscopic surgical debridement. We then changed the fluconazole into amphotericin B due to the abnormal signs in the liver function tests, although the fluconazole successfully controlled fungemia and arthritis. To the best of our knowledge, this is the first case of candida arthritis in patients with maintenance hemodialysis in South Korea. [ABSTRACT FROM AUTHOR]

We present the optimization of a birefringence-enhanced-waveguide (BWG)-based polarization beam splitter (PBS) in a Mach-Zehnder interferometer (MZI) configuration and analyze the structure-dependent or polarization-dependent phase difference, using a delay-line MZI (DL-MZI). We fabricate the DL-MZI using silica-based planar lightwave circuit technology and, using the DL-MZI, demonstrate the ability to optimize a PBS by measuring the birefringence of the BWG and structure-dependent phase offset. [ABSTRACT FROM AUTHOR]

Flow aggregation is a scalable method to provide quality of service guarantees to a large number of flows economically. A round-robin scheduler is an efficient scheduling algorithm. We investigate flow aggregation using a round-robin scheduler and propose the use of periodic timer interrupts for rate control of the round-robin scheduler. The proposed flow aggregator is a single-stage scheduler compared to Cobb's two-stage flow aggregator consisting of an aggregator and non-aggregating scheduler. It is possible to implement flow aggregation in the existing routers with only a software upgrade. We also present a simulation study showing the delay behaviors of the proposed algorithm. [ABSTRACT FROM AUTHOR]

In this paper, we present the fabrication of 40 Gb/s traveling-wave electroabsorption modulator-integrated laser (TW-EML) modules. A selective area growth method is first employed in 40 Gb/s EML fabrication to simultaneously provide active layers for lasers and modulators. The 3 dB bandwidth of a TW-EML module is measured to be 34 GHz, which is wider than that of a lumped EML module. The 40 Gb/s non-return-to-zero eye diagram shows clear openings with an average output power of +0.5 dBm. [ABSTRACT FROM AUTHOR]

We have developed 40-Gb/s traveling-wave electroabsorption-modulator-integrated distributed feedback laser (TW-EML) modules using several advanced technologies. First, we have adopted a selective area growth (SAG) method in the fabrication of the 40-Gb/s EML device to provide active layers for the laser and the electroabsorption modulators (EAMs) simultaneously. The fabricated device shows that the measured 3-dB bandwidth of electrical-to-optical (E/O) response reaches about 45 GHz and the return loss (S11) is kept below -10 dB up to 50GHz. For the module design of the device, we mainly considered electrical and optical factors. The measured S11 of the fabricated 40 Gb/s TW-EML module is below -10 dB up to about 30 GHz and the 3-dB bandwidth of the E/O response reaches over 35 GHz. We also have developed two types of coplanar waveguide (CPW) for the application of the driver amplifier integrated 40 Gb/s TW-EML module, which is a system-on-package (SoP) composed of an EML device and a driver amplifier device in a module. The measured S11 of the two-step-bent CPW is below -10 dB up to 35 GHz and the measured S11 of the parallel type CPW is below -10 dB up to 39 GHz. [ABSTRACT FROM AUTHOR]

We propose crossed stripe-electrode patterns for a vertically-aligned liquid crystal (LC) cell. The proposed electrode structure forms the radial LC distribution with the point singularity S = + 1 in the presence of the applied electric field, resulting in the wide viewing angle characteristics as well as the reduced color-shift compared to the conventional patterned vertical alignment (PVA) cell. Moreover, the radial LC distribution with the point singularity results in an increased transmittance compared to the conventional PVA cell, because the region with zero transmittance only occurs at the singular point. [ABSTRACT FROM AUTHOR]