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Abstract Background Osteoarthritis (OA) is the most common type of degenerative arthritis and affects the entire joint, causing pain, joint inflammation, and cartilage damage. Various risk factors are implicated in causing OA, and in recent years, a lot of research and interest have been directed toward chronic low-grade inflammation in OA. Monocyte chemoattractant protein-1 (MCP-1; also called CCL2) acts through C–C chemokine receptor type 2 (CCR2) in monocytes and is a chemotactic factor of monocytes that plays an important role in the initiation of inflammation. The targeting of CCL2–CCR2 is being studied as part of various topics including the treatment of OA. Methods In this study, we evaluated the potential therapeutic effects the sCCR2 E3 gene may exert on OA. The effects of sCCR2 E3 were investigated in animal experiments consisting of intra-articular injection of sCCR2 E3 in a monosodium iodoacetate (MIA)-induced OA rat model. The effects after intra-articular injection of sCCR2 E3 (fusion protein encoding 20 amino acids of the E3 domain of the CCL2 receptor) in a monosodium iodoacetate-induced OA rat model were compared to those in rats treated with empty vector (mock treatment) and full-length sCCR2. Results Pain improved with expression of the sCCR2 gene. Improved bone resorption upon sCCR2 E3 gene activation was confirmed via bone analyses using micro-computed tomography. Histologic analyses showed that the sCCR2 E3 gene exerted protective effects against cartilage damage and anti-inflammatory effects on joints and the intestine. Conclusions These results show that sCCR2 E3 therapy is effective in reducing pain severity, inhibiting cartilage destruction, and suppressing intestinal damage and inflammation. Thus, sCCR2 E3 may be a potential therapy for OA.

Osteoarthritis (OA) is a degenerative disease that induces pain, cartilage deformation, and joint inflammation. Mesenchymal stem cells (MSCs) are potential therapeutic agents for treatment of OA. However, MSC therapy can cause excessive inflammation. Signal transducer and activator of transcription 3 (STAT3) modulates secretion of many proinflammatory cytokines. Experimental OA was induced by intra-articular (IA) injection of monosodium iodoacetate (MIA) to the right knee of rats. MSCs from OA patients (OA-MSCs) were treated with STA21, a small molecule that blocks STAT3 signaling, by IA or intravenous (IV) injection after MIA injection. Pain severity was quantified by assessment of secondary tactile allodynia using the von Frey assessment test. Cartilage degradation was measured by microcomputed tomography image analysis, histological analysis, and the Mankin score. Protein and gene expression was evaluated by enzyme-linked immunosorbent assay, immunohistochemistry, and real-time polymerase chain reaction. MSCs increased production of proinflammatory cytokines under inflammatory conditions. STA21 significantly decreased expression of these proinflammatory molecules via inhibition of STAT3 activity but increased gene expression of molecules related to migration potential and immunomodulation in OA-MSCs. STAT3-inhibited OA-MSCs administrated by IV or IA injection decreased pain severity and cartilage damage in rats with MIA-induced OA rats by decreasing proinflammatory cytokines in the joints. Combined IA and IV-injected STAT3-inhibited OA-MSCs had an additive effect of pain relief in MIA-induced OA rats. STAT3 inhibition may optimize the therapeutic activities of MSCs for treating OA by attenuating pain and progression of MIA by inhibiting inflammation and cartilage damage.

BackgroundAs health care continues to evolve with technological advancements, the integration of artificial intelligence into clinical practices has shown promising potential to enhance patient care and operational efficiency. Among the forefront of these innovations are large language models (LLMs), a subset of artificial intelligence designed to understand, generate, and interact with human language at an unprecedented scale. ObjectiveThis systematic review describes the role of LLMs in improving diagnostic accuracy, automating documentation, and advancing specialist education and patient engagement within the field of gastroenterology and gastrointestinal endoscopy. MethodsCore databases including MEDLINE through PubMed, Embase, and Cochrane Central registry were searched using keywords related to LLMs (from inception to April 2024). Studies were included if they satisfied the following criteria: (1) any type of studies that investigated the potential role of LLMs in the field of gastrointestinal endoscopy or gastroenterology, (2) studies published in English, and (3) studies in full-text format. The exclusion criteria were as follows: (1) studies that did not report the potential role of LLMs in the field of gastrointestinal endoscopy or gastroenterology, (2) case reports and review papers, (3) ineligible research objects (eg, animals or basic research), and (4) insufficient data regarding the potential role of LLMs. Risk of Bias in Non-Randomized Studies—of Interventions was used to evaluate the quality of the identified studies. ResultsOverall, 21 studies on the potential role of LLMs in gastrointestinal disorders were included in the systematic review, and narrative synthesis was done because of heterogeneity in the specified aims and methodology in each included study. The overall risk of bias was low in 5 studies and moderate in 16 studies. The ability of LLMs to spread general medical information, offer advice for consultations, generate procedure reports automatically, or draw conclusions about the presumptive diagnosis of complex medical illnesses was demonstrated by the systematic review. Despite promising benefits, such as increased efficiency and improved patient outcomes, challenges related to data privacy, accuracy, and interdisciplinary collaboration remain. ConclusionsWe highlight the importance of navigating these challenges to fully leverage LLMs in transforming gastrointestinal endoscopy practices. Trial RegistrationPROSPERO 581772; https://www.crd.york.ac.uk/prospero/

Gastritis is a disease characterized by inflammation of the gastric mucosa. It is very common and has various classification systems such as the updated Sydney system. As there is a lot of evidence that Helicobacter pylori infection is associated with the development of gastric cancer and that gastric cancer can be prevented by eradication, H. pylori gastritis has been emphasized recently. The incidence rate of gastric cancer in Korea is the highest in the world, and due to the spread of screening endoscopy, atrophic gastritis and intestinal metaplasia are commonly diagnosed in the general population. However, there have been no clinical guidelines developed in Korea for these lesions. Therefore, this clinical guideline has been developed by the Korean College of Helicobacter and Upper Gastrointestinal Research for important topics that are frequently encountered in clinical situations related to gastritis. Evidence-based guidelines were developed through systematic review and de novo processes, and eight recommendations were made for eight key questions. This guideline needs to be periodically revised according to the needs of clinical practice or as important evidence about this issue is published in the future.

Background: The large language model (LLM) has the potential to be applied to clinical practice. However, there has been scarce study on this in the field of gastroenterology. Aim: This study explores the potential clinical utility of two LLMs in the field of gastroenterology: a customized GPT model and a conventional GPT-4o, an advanced LLM capable of retrieval-augmented generation (RAG). Method: We established a customized GPT with the BM25 algorithm using Open AI’s GPT-4o model, which allows it to produce responses in the context of specific documents including textbooks of internal medicine (in English) and gastroenterology (in Korean). Also, we prepared a conventional ChatGPT 4o (accessed on 16 October 2024) access. The benchmark (written in Korean) consisted of 15 clinical questions developed by four clinical experts, representing typical questions for medical students. The two LLMs, a gastroenterology fellow, and an expert gastroenterologist were tested to assess their performance. Results: While the customized LLM correctly answered 8 out of 15 questions, the fellow answered 10 correctly. When the standardized Korean medical terms were replaced with English terminology, the LLM’s performance improved, answering two additional knowledge-based questions correctly, matching the fellow’s score. However, judgment-based questions remained a challenge for the model. Even with the implementation of ‘Chain of Thought’ prompt engineering, the customized GPT did not achieve improved reasoning. Conventional GPT-4o achieved the highest score among the AI models (14/15). Although both models performed slightly below the expert gastroenterologist’s level (15/15), they show promising potential for clinical applications (scores comparable with or higher than that of the gastroenterology fellow). Conclusions: LLMs could be utilized to assist with specialized tasks such as patient counseling. However, RAG capabilities by enabling real-time retrieval of external data not included in the training dataset, appear essential for managing complex, specialized content, and clinician oversight will remain crucial to ensure safe and effective use in clinical practice.

Objective: We previously developed artificial intelligence (AI) diagnosis algorithms for predicting the six classes of stomach lesions. However, this required significant computational resources. The incorporation of AI into medical devices has evolved from centralized models to decentralized edge computing devices. In this study, a deep learning endoscopic image classification model was created to automatically categorize all phases of gastric carcinogenesis using an edge computing device. Design: A total of 15,910 endoscopic images were collected retrospectively and randomly assigned to train, validation, and internal-test datasets in an 8:1:1 ratio. The major outcomes were as follows: 1. lesion classification accuracy in six categories: normal/atrophy/intestinal metaplasia/dysplasia/early/advanced gastric cancer; and 2. the prospective evaluation of classification accuracy in real-world procedures. Results: The internal-test lesion-classification accuracy was 93.8% (95% confidence interval: 93.4–94.2%); precision was 88.6%, recall was 88.3%, and F1 score was 88.4%. For the prospective performance test, the established model attained an accuracy of 93.3% (91.5–95.1%). The established model’s lesion classification inference speed was 2–3 ms on GPU and 5–6 ms on CPU. The expert endoscopists reported no delays in lesion classification or any interference from the deep learning model throughout their exams. Conclusions: We established a deep learning endoscopic image classification model to automatically classify all stages of gastric carcinogenesis using an edge computing device.

With an aging population, the number of patients with difficulty swallowing due to medical conditions is gradually increasing. In such cases, enteral nutrition is administered through a temporary nasogastric tube. Long-term use of a nasogastric tube leads to various complications and a decreased quality of life. Percutaneous endoscopic gastrostomy (PEG) is the percutaneous placement of a tube into the stomach, aided endoscopically, which may be an alternative to a nasogastric tube when enteral nutritional is required for 4 weeks or more. This paper is the first Korean clinical guideline for PEG. It was developed jointly by the Korean College of Helicobacter and Upper Gastrointestinal Research and led by the Korean Society of Gastrointestinal Endoscopy. These guidelines aimed to provide physicians, including endoscopists, with the indications, use of prophylactic antibiotics, timing of enteric nutrition, tube placement methods, complications, replacement, and tubes removal for PEG based on the currently available clinical evidence.

Background/objectives: Bismuth is commonly used in Helicobacter pylori (H. pylori) eradication therapy. However, few studies have examined the in vitro susceptibility of H. pylori to bismuth. Moreover, the exact mechanism of action of bismuth on H. pylori remains unclear. The aim of this study was to identify the anti-bacterial effect of bismuth as well as to evaluate potential synergistic effects between bismuth and various antibiotics. Methods: The minimum inhibitory concentrations (MICs) of three bismuth preparations, bismuth subsalicylate, bismuth potassium citrate, and colloidal bismuth subcitrate (CBS, De-Nol) were determined for H. pylori strains using the agar dilution technique. Agar plates of varying pH values from 5.0 to 8.0 were used to investigate whether acidity influences the anti-bacterial effect of bismuth. A checkerboard assay was performed to assess the synergism between CBS and antibiotics (amoxicillin, clarithromycin, and metronidazole). Results: Twelve H. pylori strains, including three reference strains (H. pylori 26695, J99, and ATCC 43504), and nine clinically isolated strains were tested. The MICs for bismuth subsalicylate, bismuth potassium citrate, and CBS ranged from 4 to 32 μg/mL, 2 to 16 μg/mL, and 1 to 8 μg/mL, respectively. The bismuth MICs for the reference strains were similar at pH 5–8. In the checkerboard assay, no interactions between CBS and any of the antibiotics were observed in the reference H. pylori strains. Conclusions: Bismuth showed in vitro susceptibility against H. pylori. The enhanced eradication efficacy of bismuth-containing regimens appears to be due to mechanisms other than direct synergy with antibiotics.

With an aging population, the number of patients with difficulty in swallowing due to medical conditions is gradually increasing. In such cases, enteral nutrition is administered through a temporary nasogastric tube. However, the long-term use of a nasogastric tube leads to various complications and a decreased quality of life. Percutaneous endoscopic gastrostomy (PEG) is the percutaneous placement of a tube into the stomach that is aided endoscopically and may be an alternative to a nasogastric tube when enteral nutritional is required for four weeks or more. This paper is the first Korean clinical guideline for PEG developed jointly by the Korean College of Helicobacter and Upper Gastrointestinal Research and led by the Korean Society of Gastrointestinal Endoscopy. These guidelines aimed to provide physicians, including endoscopists, with the indications, use of prophylactic antibiotics, timing of enteric nutrition, tube placement methods, complications, replacement, and tubes removal for PEG based on the currently available clinical evidence.

With an aging population, the number of patients with difficulty in swallowing due to medical conditions is gradually increasing. In such cases, enteral nutrition is administered through a temporary nasogastric tube. However, the long-term use of a nasogastric tube leads to various complications and a decreased quality of life. Percutaneous endoscopic gastrostomy (PEG) is the percutaneous placement of a tube into the stomach that is aided endoscopically and may be an alternative to a nasogastric tube when enteral nutritional is required for four weeks or more. This paper is the first Korean clinical guideline for PEG developed jointly by the Korean College of Helicobacter and Upper Gastrointestinal Research and led by the Korean Society of Gastrointestinal Endoscopy. These guidelines aimed to provide physicians, including endoscopists, with the indications, use of prophylactic antibiotics, timing of enteric nutrition, tube placement methods, complications, replacement, and tube removal for PEG based on the currently available clinical evidence.

BackgroundObesity, characterized by excessive fat accumulation, poses a significant public health challenge globally. Recent advancements in medical technology have heralded the emergence of endoscopic bariatric treatments (EBTs) as innovative alternatives to conventional obesity interventions. Despite previous systematic reviews and network meta-analyses, they also highlighted discrepancies in outcomes and efficacy among different EBTs. Here, we will update a systematic review and network meta-analysis of randomized controlled trials (RCTs) focusing on EBTs and presents a protocol for the reproducibility and transparency.MethodsThe core protocol of this study was registered at PROSPERO database (CRD42024514249) on Jan 2024. Core databases including MEDLINE through PubMed, Embase, and Cochrane library will be searched relevant studies, and a systematic review with network meta-analysis will be performed. Two evaluators (EJ Gong and CS Bang) will independently screen the titles and abstracts following the eligibility criteria; (1) RCTs investigated the compared the efficacy of EBTs and controls; (2) studies published in English; and (3) studies in full-text format. We will exclude studies meeting the following criteria; (1) studies that did not report the treatment outcomes, such as percent excess weight loss or percent total body weight loss; (2) case reports and review articles; (3) ineligible research objects, for example, animals or children; and (4) insufficient data regarding treatment outcome. The primary outcomes will be the common efficacy metric found after systematic review of relevant studies, such as percent excess weight loss or percent total body weight loss with a follow-up of at least 6 months. Narrative (descriptive) synthesis is planned and quantitative synthesis will be used if the included studies are sufficiently homogenous. The quality of the identified studies will be assessed using the Cochrane Risk of Bias assessment tool version 2.0 (ROB 2.0). All the systematic review and network meta-analysis process will be undertaken keeping the principles of the Preferred Reporting Items for a Systematic Review and Meta-analysis for systematic review protocols (PRISMA-P) and PRISMA Extension Statement for Reporting of Systematic Reviews Incorporating Network Meta-analyses of Health Care Interventions (PRISMA-NMA).DiscussionThis updated systematic review and network meta-analysis will provide information about comparative efficacy of various EBTs and this will help physicians in the decision-making process for the selection of treatment modalities in the clinical practice.

BackgroundOur research group previously established a deep-learning–based clinical decision support system (CDSS) for real-time endoscopy-based detection and classification of gastric neoplasms. However, preneoplastic conditions, such as atrophy and intestinal metaplasia (IM) were not taken into account, and there is no established model that classifies all stages of gastric carcinogenesis. ObjectiveThis study aims to build and validate a CDSS for real-time endoscopy for all stages of gastric carcinogenesis, including atrophy and IM. MethodsA total of 11,868 endoscopic images were used for training and internal testing. The primary outcomes were lesion classification accuracy (6 classes: advanced gastric cancer, early gastric cancer, dysplasia, atrophy, IM, and normal) and atrophy and IM lesion segmentation rates for the segmentation model. The following tests were carried out to validate the performance of lesion classification accuracy: (1) external testing using 1282 images from another institution and (2) evaluation of the classification accuracy of atrophy and IM in real-world procedures in a prospective manner. To estimate the clinical utility, 2 experienced endoscopists were invited to perform a blind test with the same data set. A CDSS was constructed by combining the established 6-class lesion classification model and the preneoplastic lesion segmentation model with the previously established lesion detection model. ResultsThe overall lesion classification accuracy (95% CI) was 90.3% (89%-91.6%) in the internal test. For the performance validation, the CDSS achieved 85.3% (83.4%-97.2%) overall accuracy. The per-class external test accuracies for atrophy and IM were 95.3% (92.6%-98%) and 89.3% (85.4%-93.2%), respectively. CDSS-assisted endoscopy showed an accuracy of 92.1% (88.8%-95.4%) for atrophy and 95.5% (92%-99%) for IM in the real-world application of 522 consecutive screening endoscopies. There was no significant difference in the overall accuracy between the invited endoscopists and established CDSS in the prospective real-clinic evaluation (P=.23). The CDSS demonstrated a segmentation rate of 93.4% (95% CI 92.4%-94.4%) for atrophy or IM lesion segmentation in the internal testing. ConclusionsThe CDSS achieved high performance in terms of computer-aided diagnosis of all stages of gastric carcinogenesis and demonstrated real-world application potential.

Background/Aims The eradication success rate of Helicobacter pylori (H. pylori) infection with a first-line standard triple therapy (STT) has been decreasing in Korea. However, treatment outcomes of H. pylori infection in Yeongdong, Gangwon Province have been scarcely reported. This study aimed to investigate the treatment outcomes of H. pylori infection in a single tertiary care hospital with regional characteristics. Materials and Methods From July 2018 to June 2019, a total of 592 patients who underwent STT consisting of a proton pump inhibitor, amoxicillin, and clarithromycin for 7 to 14 days as a first-line H. pylori eradication therapy were included. Demographic data and treatment outcomes were retrospectively reviewed using medical records. Results The median age of 592 patients was 58 years (range 23 to 86) and 329 patients (55.6%) were men. The indication for eradication therapy included chronic atrophic gastritis (57.9%), peptic ulcer disease (19.6%), and gastric neoplasm after endoscopic resection (5.9%). Most patients (92.2%) received a 7-day course of STT. Eradication rate of STT was 64.0% (379/592). Rescue therapy was performed in 146 patients, and the final eradication rate reached 85.6% (507/592). Conclusions Eradication rate of STT in Yeongdong area of Gangwon Province was unsatisfactory, warranting the consideration of a first-line eradication regimen other than STT.

Abstract The optimal timing of endoscopy in patients with acute upper gastrointestinal bleeding (UGIB) remains controversial. In this study, we investigated the clinical outcomes of urgent endoscopy in patients with UGIB compared with elective endoscopy. From January 2016 to December 2018, consecutive patients who visited the emergency department and underwent endoscopy for clinical manifestations of acute UGIB, including variceal bleeding, were eligible. Urgent endoscopy (within 6 h) and elective endoscopy (after 6 h) were defined as the time taken to perform endoscopy after presentation to the emergency department. The primary outcome was mortality rate within 30 days. A total of 572 patients were included in the analysis. Urgent endoscopy was performed in 490 patients (85.7%). The 30-day mortality rate did not differ between the urgent and elective endoscopy groups (5.3% and 6.1%, p = 0.791). There was no difference regarding the recurrent bleeding rate, total amount of transfusion, or length of hospital between the groups. In multivariate analysis, age and the amount of transfusion were associated with mortality. Urgent endoscopy was not associated with a lower 30-day mortality rate compared with elective endoscopy in patients with acute UGIB.

Abstract Background Ingested foreign objects frequently require emergency removal. This study aimed to investigate the clinical outcomes of endoscopic removal of foreign bodies from the upper gastrointestinal tract and the risk factors for adverse events. Methods Adults (> 18 years) who underwent endoscopic management of ingested foreign bodies at two centers, one inland and one on the coast, between January 2008 and December 2017 were eligible. Clinical characteristics and procedure-related outcomes were retrospectively reviewed. Patients were divided into two groups, based on whether the foreign bodies were sharp or blunt in shape. Results A total of 853 patients aged 19–96 years were analyzed. Ingestion of fish bones was more common in the coastal area, whereas ingestion of food boluses was more common in the inland area. The duration of impaction ranged from 1 h to over 1 month and was significantly longer in patients who ingested blunt than sharp foreign bodies (15 vs. 5 h, p

Abstract Background Risk stratification before endoscopy is crucial for proper management of patients suspected as having upper gastrointestinal bleeding (UGIB). There is no consensus regarding the role of nasogastric lavage for risk stratification. In this study, we investigated the usefulness of nasogastric lavage to identify patients with UGIB requiring endoscopic examination. Methods From January 2017 to December 2018, patients who visited the emergency department with a clinical suspicion of UGIB and who underwent nasogastric lavage before endoscopy were eligible. Patients with esophagogastric variceal bleeding were excluded. The added predictive ability of nasogastric lavage to the Glasgow–Blatchford score (GBS) was estimated using category-free net reclassification improvement and integrated discrimination improvement. Results Data for 487 patients with nonvariceal UGIB were analyzed. The nasogastric aspirate was bloody in 67 patients (13.8 %), coffee-ground in 227 patients (46.6 %), and clear in 193 patients (39.6 %). The gross appearance of the nasogastric aspirate was associated with the presence of UGIB. Model comparisons showed that addition of nasogastric lavage findings to the GBS improved the performance of the model to predict the presence of UGIB. Subgroup analysis showed that nasogastric lavage improved the performance of the prediction model in patients with the GBS ≤ 11, whereas no additive value was found when the GBS was greater than 11. Conclusions Nasogastric lavage is useful for predicting the presence of UGIB in a subgroup of patients, while its clinical utility is limited in high-risk patients with a GBS of 12 or more.

Antithrombotic agents, including antiplatelet agents and anticoagulants, are increasingly used in South Korea. The management of patients using antithrombotic agents and requiring gastrointestinal endoscopy is an important clinical challenge. Although clinical practice guidelines (CPGs) for the management of patients receiving antithrombotic agents and undergoing gastrointestinal endoscopy have been developed in the Unites States, Europe, and Asia Pacific region, it is uncertain whether these guidelines can be adopted in South Korea. After reviewing current CPGs, we identified unmet needs and recognized significant discrepancies in the clinical practice among regions. This is the first CPG in Korea providing information that may assist endoscopists in the management of patients on antithrombotic agents who require diagnostic or elective therapeutic endoscopy. This guideline was developed through the adaptation process as an evidence-based method, with four guidelines retrieved by systematic review. Eligible guidelines were evaluated according to the Appraisal of Guidelines for Research and Evaluation II process, and 13 statements were established using a grading system. This guideline was reviewed by external experts before an official. It will be revised as necessary to cover changes in technology, evidence, or other aspects of clinical practice.

The stomach is the most common primary site of an extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) type, which is characterized by an indolent clinical course. A diagnosis of gastric MALT lymphoma requires an endoscopic biopsy that should be confirmed by an experienced pathologist. Gastric MALT lymphoma shows a variable endoscopic appearance, including erosion, erythema, discoloration, atrophy, ulcer, and subepithelial lesion. The distribution is often multifocal. Therefore, clinical suspicion and multiple biopsies are essential for an accurate diagnosis. Gastric MALT lymphoma is almost invariably associated with a Helicobacter pylori (H. pylori) infection. H. pylori eradication therapy is the mainstay of treatment, which must be delivered to all patients regardless of the H. pylori infection status or stage. For patients who have failed to achieve remission following eradication therapy, radiotherapy or chemotherapy can be considered. Radiotherapy is an effective treatment modality for a localized stage and shows excellent outcomes. In the presence of disseminated or advanced disease, chemotherapy and/or immunotherapy with the anti-CD20 monoclonal antibody, rituximab, can be applied. Treatment should be individualized according to the stage and symptoms, as well as the patients’ preference. Given that the clinical course of gastric MALT lymphoma is usually indolent, watchful waiting may be an adequate strategy in selected cases where scheduled follow-up is guaranteed.

Endoscopic bariatric therapies that emulate some of the principles of bariatric surgery have been developed as a less invasive option for the treatment of obesity and related comorbidities. Small bowel endoscopic bariatric therapies include bypass sleeves, incisionless anastomosis systems, and duodenal mucosal resurfacing. Clinical experience with small bowel devices suggests that endoscopic bariatric procedures can be safely implemented and that these devices are effective for both weight loss and metabolic improvement. Although the mechanisms behind these effects should be further elucidated, endoscopic bariatric therapies may be more effective and safer adjunctive interventions than lifestyle modifications and pharmacological regimens for patients with obesity or obesity-related comorbidities.

Antimicrobial resistance is a growing problem in the eradication of Helicobacter pylori. A combination therapy with proton pump inhibitor, clarithromycin, and amoxicillin is recommended as the first-line treatment regimen in Korea. However, the eradication rate with a standard triple therapy has been unsatisfactory in the last decade, and one of the main reasons for treatment failure is the increasing prevalence of strains resistant to antimicrobials. Therefore, comprehensive and detailed information on antimicrobial resistance is mandatory to optimize the strategy of eradication treatment. The antimicrobial resistance of H. pylori is reported to vary according to study population, geographical region, and test methods. In this review, the prevalence of antimicrobial resistance of H. pylori isolates in Korea is summarized on the basis of recent studies.

Background/AimsWe aimed to investigate whether the current indications for curative endoscopic resection (ER) of gastric cancer (GC) can be applied to GC caused by adenoma. Additionally, we attempted to identify factors predictive of lesions subsequently found in addition to the expanded indications for ER.Methods : We retrospectively analyzed 342 patients diagnosed with GC caused by adenoma who underwent ER at a single tertiary center between February 2011 and December 2014. The gross whole tumor size was measured using the endoscopically resected specimen. The microscopic whole tumor size was measured using mapping paper. The estimated cancer size was calculated using the microscopic whole tumor size and the square root of the carcinoma component.Results : A gross whole tumor size ≥3 cm, carcinoma component ≥35%, and gross ulceration were predictive of lesions other than the expanded indications for ER. The overall rate of lymph node metastasis was 0.3% (1/327), which only occurred in one patient with a lesion other than the expanded indications (4.5%, 1/22).Conclusion : sThe current indications for curative ER in GC can be applied to GC caused by adenoma. In cases suspected of having lesions other than the expanded indications, patients should be cautiously selected for ER to reduce the risk of an inappropriate procedure.

Background/AimsBecause of the poor prognosis of diffuse-type gastric cancer, early detection is important. We investigated the clinical characteristics and prognosis of diffuse-type early gastric cancer (EGC) diagnosed in subjects during health check-ups.Methods : Among 121,111 subjects who underwent gastroscopy during a routine health check-up, we identified 282 patients with 286 EGC lesions and reviewed their clinical and tumor-specific parameters.Results : Patients with diffuse-type EGC were younger, and 48.1% of them were female. Serum anti-Helicobacter pylori IgG (Hp-IgG) was positive in 90.7% of diffuse-type EGC patients (vs 75.9% of intestinal-type EGC, p=0.002), and the proportion of diffuse-type EGC cases increased significantly with increasing Hp-IgG serum titers (p

Background/Aims The detection of multifocal lesions is important for the successful management of gastric neoplasms. We investigated the characteristics of missed simultaneous lesions and the reason for the missed diagnoses. Methods A total of 140 patients who underwent repeat endoscopy before endoscopic resection between June 2013 and June 2014 were retrospectively reviewed. We classified simultaneous lesions into three groups based on a review of earlier images: group 1, no images of the location of simultaneous lesions were taken; group 2, no corresponding lesion was evident in the previous images; and group 3, simultaneous lesions were visible in the earlier images but a biopsy was not performed. Results Simultaneous lesions were found in 12 patients (8.6%) with 13 lesions, comprising 10 dysplasia (76.9%) and three adenocarcinoma (23.1%). Regarding the reasons for missed diagnoses, seven lesions (53.8%) were classified as group 3, five (38.5%) as group 1, and the remaining lesion (7.7%) as group 2. There were no significant differences in the characteristics of the patients with and without simultaneous lesions. Conclusions Lesions disregarded or unnoticed during endoscopic examination were the main reason for missed diagnosis of simultaneous lesions. Endoscopists should consider the possibility of simultaneous lesions and attempt to meticulously evaluate the entire gastric mucosa.

Subepithelial lesions occasionally found in the stomach of patients undergoing endoscopy may be either benign lesions or tumors with malignant potential. They may also appear due to extrinsic compression. Discrimination of gastric subepithelial lesions begins with meticulous endoscopic examination for size, shape, color, mobility, consistency, and appearance of the overlying mucosa. Accurate diagnosis can be achieved with endoscopic ultrasonography, which provides useful information on the exact size, layer-of-origin, and characteristic morphologic features to support a definitive diagnosis. Endoscopic ultrasonography also aids in the prediction of malignant potential, especially in gastrointestinal stromal tumors. Features of subepithelial lesions identified on endoscopic ultrasonography can be used to determine whether further diagnostic procedures such as endoscopic resection, fine needle aspiration, or core biopsy are required. Endoscopic ultrasonography is a valuable tool for diagnosis and clinical decision making during follow-up of gastric subepithelial lesions.

Background/AimsWe investigated the effectiveness of Helicobacter pylori eradication therapy for gastric mucosa-associated lymphoid tissue (MALT) lymphoma regardless of the H. pylori infection status or disease stage.Methods : From November 1995 to September 2014, 345 subjects who were diagnosed with gastric MALT lymphoma and had received eradication therapy as their first-line treatment were eligible for inclusion in this study. A retrospective review was performed using the medical records.Results : Of the 345 patients, H. pylori infection was detected in 317 patients (91.9%). The complete remission (CR) rate after eradication therapy was 82.3%, which was higher in H. pylori-positive patients than in H. pylori-negative patients (84.5% vs 57.1%, p=0.001). CR rates after eradication did not present significant differences between stages, and the CR rate was 83.3% for stage IE1 and 74.4% for stage IE2 or above (p=0.167). The overall CR rate was 87.2% after additional treatment, and neither H. pylori infection status nor stage showed differences according to the treatment response.Conclusion : sEradication therapy led to CR in 57.1% of H. pylori-negative patients and in 74.4% of patients with stage IE2 or above. Eradication therapy is worthwhile as an initial treatment for gastric MALT lymphoma regardless of the H. pylori infection status and stage.

Background/AimsGastrointestinal involvement in vasculitis may result in life-threatening complications. However, its variable clinical presentations and endoscopic features, and the rarity of the disease, often result in delayed diagnosis.Methods : Clinical characteristics, endoscopic features, and histopathological findings were reviewed from medical records.Results : Of 6,477 patients with vasculitis, 148 were diagnosed as primary vasculitis with upper gastrointestinal involvement. Of these, 21 cases (14.2%) were classified as large-vessel vasculitis, 17 cases (11.5%) as medium-vessel vasculitis, and 110 cases (74.3%) as small-vessel vasculitis. According to the specific diagnosis, IgA vasculitis (Henoch-Schönlein purpura) was the most common diagnosis (56.8%), followed by Takayasu arteritis (14.1%), microscopic polyangiitis (10.1%), and polyarteritis nodosa (6.8%). Gastrointestinal symptoms were present in 113 subjects (76.4%), with abdominal pain (78.8%) the most common symptom. Erosion and ulcers were striking endoscopic features, and the second portion of the duodenum was the most frequently involved site. Biopsy specimens were obtained from 124 patients, and only eight (5.4%) presented histopathological signs of vasculitis.Conclusion : sDiagnosis of vasculitis involving the upper gastrointestinal tract is difficult. Because of the widespread use of endoscopy, combining clinical features with endoscopic findings may facilitate making appropriate diagnoses; however, the diagnostic yield of endoscopic biopsy is low.

Data on implications of a high positive titer of serum anti-Helicobacter pylori antibody on gastric cancer (GC) is limited. This study aimed to investigate the characteristics of GC with a high serum anti-H. pylori IgG (Hp-IgG) titer, and its association with diffuse-type GC.We analyzed clinical and histological characteristics of 917 non-cardia GC patients who underwent gastrectomy. H. pylori infection was determined serologically by measuring Hp-IgG titer with immunoassay. Seropositive patients were divided into three groups (low-positive, mid-positive, and high-positive) according to the Hp-IgG titer value. Tumors were classified according to the Lauren criteria as diffuse or intestinal types.The median age of the patients was 59.0 years, and 33.8% were female. The patents were grouped as follows: seronegative, 188 (20.5%); low-positive, 288 (31.4%); mid-positive, 290 (31.6%); and high-positive 151 (16.5%). The high-positive group was significantly younger (median age, 55.0 years), with a higher proportion of female (45.0%) and non-smokers (58.9%). The proportion of diffuse-type GC increased in the order low-, mid-, and high-positive groups (p