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Abstract This study assessed pretreatment breast MRI coupled with machine learning for predicting early clinical responses to neoadjuvant chemotherapy (NAC) in triple-negative breast cancer (TNBC), focusing on identifying non-responders. A retrospective analysis of 135 TNBC patients (107 responders, 28 non-responders) treated with NAC from January 2015 to October 2022 was conducted. Non-responders were defined according to RECIST guidelines. Data included clinicopathologic factors and clinical MRI findings, with radiomics features from contrast-enhanced T1-weighted images, to train a stacking ensemble of 13 machine learning models. For subgroup analysis, propensity score matching was conducted to adjust for clinical disparities in NAC response. The efficacy of the models was evaluated using the area under the receiver-operating-characteristic curve (AUROC) before and after matching. The model combining clinicopathologic factors and clinical MRI findings achieved an AUROC of 0.752 (95% CI 0.644–0.860) for predicting non-responders, while radiomics-based models showed 0.749 (95% CI 0.614–0.884). An integrated model of radiomics, clinicopathologic factors, and clinical MRI findings reached an AUROC of 0.802 (95% CI 0.699–0.905). After propensity score matching, the hierarchical order of key radiomics features remained consistent. Our study demonstrated the potential of using machine learning models based on pretreatment MRI to non-invasively predict TNBC non-responders to NAC.

Background/Aims There is limited knowledge regarding the management of duodenal subepithelial lesions (SELs) owing to a lack of understanding of their natural course. This study aimed to assess the natural course of asymptomatic duodenal SELs and provide management recommendations. Methods Patients diagnosed with duodenal SELs and followed up for a minimum of 6 months were retrospectively investigated. Results Among the 443,533 patients who underwent esophagogastroduodenoscopy between 2008 and 2020, duodenal SELs were identified in 0.39% (1,713 patients). Among them, 396 duodenal SELs were monitored for a median period of 72.5 months (interquartile range, 37.7–111.3 mo). Of them, 16 SELs (4.0%) showed substantial changes in size or morphology at a median follow-up of 35.1 months (interquartile range, 21.7–51.4 mo). Of these SELs with substantial changes, tissues of two SELs were acquired using endoscopic ultrasound-guided fine needle aspiration biopsy: one was a lipoma and the other was non-diagnostic. Three SELs were surgically or endoscopically removed; two were diagnosed as gastrointestinal stromal tumors, and one was a lipoma. An initial size of 20 mm or larger was associated with substantial changes during follow-up (p = 0.016). Conclusions While the majority of duodenal SELs may not exhibit substantial interval changes, regular follow-up with endoscopy may be necessary for cases with an initial size of 20 mm or larger, considering a possibility of malignancy.

Background/Aims To overcome the technical limitations of classic endoscopic resection for gastric gastrointestinal stromal tumors (GISTs), various methods have been developed. In this study, we examined the role and feasibility of clip-and-cut procedures (clip-and-cut endoscopic full-thickness resection [cc-EFTR]) for gastric GISTs. Methods Medical records of 83 patients diagnosed with GISTs after endoscopic resection between 2005 and 2021 were retrospectively reviewed. Moreover, clinical characteristics and outcomes were analyzed. Results Endoscopic submucosal dissection (ESD) and cc-EFTR were performed in 51 and 32 patients, respectively. The GISTs were detected in the upper third of the stomach for ESD (52.9%) and cc-EFTR (90.6%). Within the cc-EFTR group, a majority of GISTs were located in the deep muscularis propria or serosal layer, accounting for 96.9%, as opposed to those in the ESD group (45.1%). The R0 resection rates were 51.0% and 84.4% in the ESD and cc-EFTR groups, respectively. Seven (8.4%) patients required surgical treatment (six patients underwent ESD and one underwent cc-EFTR,) due to residual tumor (n=5) and post-procedure adverse events (n=2). Patients undergoing R0 or R1 resection did not experience recurrence during a median 14-month follow-up period, except for one patient in the ESD group. Conclusions cc-EFTR displayed a high R0 resection rate; therefore, it is a safe and effective therapeutic option for small gastric GISTs.

Background Helicobacter pylori infection, prevalent in more than half of the global population, is associated with various gastrointestinal diseases, including peptic ulcers and gastric cancer. The effectiveness of early diagnosis and treatment in preventing gastric cancer highlights the need for improved diagnostic methods. This study aimed to develop a simple scoring system based on endoscopic findings to predict H. pylori infection. Methods A retrospective analysis was conducted on 1,007 patients who underwent upper gastrointestinal endoscopy at Asan Medical Center from January 2019 to December 2021. Exclusion criteria included prior H. pylori treatment, gastric surgery, or gastric malignancies. Diagnostic techniques included rapid urease and 13C-urea breath tests, H. pylori culture, and assessment of endoscopic features following the Kyoto gastritis classification. A new scoring system based on endoscopic findings including regular arrangement of collecting venules (RAC), nodularity, and diffuse or spotty redness was developed for predicting H. pylori infection, utilizing logistic regression analysis in the development set. Results The scoring system demonstrated high predictive accuracy for H. pylori infection in the validation set. Scores of 2 and 3 were associated with 96% and 99% infection risk, respectively. Additionally, there was a higher prevalence of diffuse redness and sticky mucus in cases where the initial H. pylori eradication treatment failed. Conclusions Our scoring system showed potential for improving diagnostic accuracy in H. pylori infection. H. pylori testing should be considered upon spotty redness, diffuse redness, nodularity, and RAC absence on endoscopic findings as determined by the predictive scoring system.

Abstract The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has evoked a worldwide pandemic. As the emergence of variants has hampered the neutralization capacity of currently available vaccines, developing effective antiviral therapeutics against SARS-CoV-2 and its variants becomes a significant challenge. The main protease (Mpro) of SARS-CoV-2 has received increased attention as an attractive pharmaceutical target because of its pivotal role in viral replication and proliferation. Here, we generated a de novo Mpro-inhibitor screening platform to evaluate the efficacies of Mpro inhibitors based on Mpro cleavage site-embedded amyloid peptide (MCAP)-coated gold nanoparticles (MCAP-AuNPs). We fabricated MCAPs comprising an amyloid-forming sequence and Mpro-cleavage sequence, mimicking in vivo viral replication process mediated by Mpro. By measuring the proteolytic activity of Mpro and the inhibitory efficacies of various drugs, we confirmed that the MCAP-AuNP-based platform was suitable for rapid screening potential of Mpro inhibitors. These results demonstrated that our MCAP-AuNP-based platform has great potential for discovering Mpro inhibitors and may accelerate the development of therapeutics against COVID-19.

Abstract Prominent techniques such as real-time polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and rapid kits are currently being explored to both enhance sensitivity and reduce assay time for diagnostic tests. Existing commercial molecular methods typically take several hours, while immunoassays can range from several hours to tens of minutes. Rapid diagnostics are crucial in Point-of-Care Testing (POCT). We propose an approach that integrates a time-series deep learning architecture and AI-based verification, for the enhanced result analysis of lateral flow assays. This approach is applicable to both infectious diseases and non-infectious biomarkers. In blind tests using clinical samples, our method achieved diagnostic times as short as 2 minutes, exceeding the accuracy of human analysis at 15 minutes. Furthermore, our technique significantly reduces assay time to just 1-2 minutes in the POCT setting. This advancement has the potential to greatly enhance POCT diagnostics, enabling both healthcare professionals and non-experts to make rapid, accurate decisions.

Objectives The incidence of treatment failures following standard triple therapy (STT) for Helicobacter pylori eradication (HPE) has reached an unacceptable level. Sequential therapy (SQ) has emerged as a promising approach to counteract the escalation of antibiotic resistance. In this study, we used a chronological cohort dataset to conduct a comparative analysis of the eradication rates, compliance, and adverse events associated with the 7-day STT and SQ. Methods A total of 789 patients underwent HPE treatment at Asan Medical Center between July 2013 and August 2017. Among them, 378 received a 7-day STT and 411 received a 10-day SQ. Baseline clinical data and treatment parameters were compared between the two treatment groups. Results SQ demonstrated an eradication rate of 84.7% (348/411), which was superior to that of the 7-day STT (74.1%; p

Abstract Diffuse large B‐cell lymphoma (DLBCL) is a heterogeneous and prevalent subtype of aggressive non‐Hodgkin lymphoma that poses diagnostic and prognostic challenges, particularly in predicting drug responsiveness. In this study, we used digital pathology and deep learning to predict responses to immunochemotherapy in patients with DLBCL. We retrospectively collected 251 slide images from 216 DLBCL patients treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R‐CHOP), with their immunochemotherapy response labels. The digital pathology images were processed using contrastive learning for feature extraction. A multi‐modal prediction model was developed by integrating clinical data and pathology image features. Knowledge distillation was employed to mitigate overfitting on gigapixel histopathology images to create a model that predicts responses based solely on pathology images. Based on the importance derived from the attention mechanism of the model, we extracted histological features that were considered key textures associated with drug responsiveness. The multi‐modal prediction model achieved an impressive area under the ROC curve of 0.856, demonstrating significant associations with clinical variables such as Ann Arbor stage, International Prognostic Index, and bulky disease. Survival analyses indicated their effectiveness in predicting relapse‐free survival. External validation using TCGA datasets supported the model's ability to predict survival differences. Additionally, pathology‐based predictions show promise as independent prognostic indicators. Histopathological analysis identified centroblastic and immunoblastic features to be associated with treatment response, aligning with previous morphological classifications and highlighting the objectivity and reproducibility of artificial intelligence‐based diagnosis. This study introduces a novel approach that combines digital pathology and clinical data to predict the response to immunochemotherapy in patients with DLBCL. This model shows great promise as a diagnostic and prognostic tool for clinical management of DLBCL. Further research and genomic data integration hold the potential to enhance its impact on clinical practice, ultimately improving patient outcomes.

Background/Aims: Although gastric neuroendocrine tumors (NETs) are uncommon neoplasms, their prevalence is increasing. The clinical importance of the World Health Organization (WHO) classification of gastric NETs, compared with NETs in other organs, has been underestimated. This study aimed to systematically evaluate the clinical and pathologic characteristics of gastric NETs based on the 2019 WHO classification and to assess the survival outcomes of patients from a single-center with a long-term follow-up. Methods: The medical records of 427 patients with gastric NETs who underwent endoscopic or surgical resection between January 2000 and March 2020 were retrospectively reviewed. All specimens were reclassified according to the 2019 WHO classification. The clinicopathologic characteristics, treatment, and oncologic outcomes of 139 gastric NETs were analyzed. Results: The patients’ median age was 53.0 years (interquartile range [IQR], 46.0 to 63.0 years). The median follow-up period was 36.0 months (IQR, 15.0 to 63.0 months). Of the patients, 92, 44, and 3 had grades 1, 2, and 3 NETs, respectively. The mean tumor size significantly increased as the tumor grade increased (p=0.025). Patients with grades 2 and 3 gastric NETs more frequently had lymphovascular invasion (29.8% vs 10.9%, p=0.005) and deeper tissue invasion (8.5% vs 0%, p=0.012) than those with grade 1 tumors. The overall disease-specific survival rate was 100%. Two patients with grades 2-3 gastric NETs experienced extragastric recurrence. Conclusions: Although gastric NETs have an excellent prognosis, grade 2 or grade 3 gastric NETs are associated with a larger size, deeper invasion, and extragastric recurrence, which require active treatment.

Background/Aims: Although an association between achalasia and esophageal cancer has been reported, whether achalasia confers a substantial increase in mortality is unknown. Moreover, the causes of death related to achalasia have not been investigated. We performed this nationwide, population-based cohort study on achalasia because no such study has been performed since the introduction of high-resolution manometry in 2008. Methods: This study was performed using data extracted from the Korean National Health Insurance Service database, covering a 9-year period from 2009 to 2017. Control participants without a diagnostic code for achalasia were randomly selected and matched by sex and birth year at a case-to-control ratio of 1:4. Data on the cause of death from Statistics Korea were also analyzed. Results: The overall incidence of achalasia was 0.68 per 100,000 person-years, and the prevalence was 6.46 per 100,000 population. Patients with achalasia (n=3,063) had significantly higher adjusted hazard ratio (aHR) for esophageal cancer (aHR, 3.40; 95% confidence interval [CI], 1.25 to 9.22; p=0.017), pneumonia (aHR, 2.30; 95% CI, 1.89 to 2.81; p

Background/Aims The treatment for gastric mucosa-associated lymphoid tissue lymphoma (MALToma) generally involves eradication of Helicobacter pylori. However, MALToma lesions may recur even without H. pylori re-infection. Furthermore, the remission rate of H. pylori-negative MALToma after eradication is low. Therefore, herein, we report on endoscopic submucosal dissection (ESD) as a treatment strategy for gastric MALToma. Methods We retrospectively reviewed the data of all patients of gastric MALToma who underwent endoscopic resection at our institution between January 2000 and December 2021. Clinical remission was defined as complete histological remission or probable minimal residual disease according to the GELA grading system for post-treatment evaluation of gastric MALToma. Results Six patients with gastric MALToma underwent ESD. Two patients were diagnosed with gastric MALToma, which improved after eradication treatment and relapsed approximately 36 and 41 months later, respectively. These patients had singular lesions localized to the mucosa and did not experience H. pylori re-infection. The lesions were successfully removed via ESD. The remaining four patients had H. pylori-negative gastric MALToma. These patients also had single, localized lesions that were removed via ESD. All the patients remained in clinical remission until the final follow-up. Conclusions ESD is a safe and effective intervention for H. pylori-negative gastric MALToma when the lesion is single and confined to the mucosal layer.

Background/Aims: Real-time polymerase chain reaction (RT-PCR) is a fast and simple method for the simultaneous detection of clarithromycin (CLR) resistance and Helicobacter pylori. We evaluated the effectiveness of RT-PCR compared to that of the rapid urease test (RUT) and assessed its value in verifying CLR resistance.Methods: A total of 70 specimens with confirmed H. pylori infection in culture were enrolled and analyzed in this prospective study. All specimens were subjected to RT-PCR assay using fluorescence melting peak signals to detect H. pylori infection and CLR resistances caused by either A2142G or A2143G mutations in the 23S ribosomal RNA gene (23S rRNA). The results were compared to those of RUT and antimicrobial susceptibility culturing tests to investigate the efficacy of RT-PCR.Results: Among the 70 specimens analyzed, the positivity rate was 97.1% (68/70) with RT-PCR and 82.9% (58/70) with RUT. CLR resistance (minimum inhibitory concentration >1.0 μg/mL) was confirmed in 18.6% (13/70), and fluorescence melting curve analysis showed that 84.6% (11/13) had point mutations in 23S rRNA. Ten specimens had only A2143G mutation, and one specimen contained both A2142G and A2143G mutations.Conclusions: RT-PCR assay was found to be more efficient than RUT in detecting H. pylori infection and could effectively verify CLR resistance compared to the antimicrobial susceptibility culturing test. Considering the high sensitivity and accessibility of RT-PCR method, it could be used to easily detect CLR-resistant H. pylori, thus helping clinicians select suitable treatment regimen and improve the eradication rate.

Abstract Since many lateral flow assays (LFA) are tested daily, the improvement in accuracy can greatly impact individual patient care and public health. However, current self-testing for COVID-19 detection suffers from low accuracy, mainly due to the LFA sensitivity and reading ambiguities. Here, we present deep learning-assisted smartphone-based LFA (SMARTAI-LFA) diagnostics to provide accurate decisions with higher sensitivity. Combining clinical data learning and two-step algorithms enables a cradle-free on-site assay with higher accuracy than the untrained individuals and human experts via blind tests of clinical data (n = 1500). We acquired 98% accuracy across 135 smartphone application-based clinical tests with different users/smartphones. Furthermore, with more low-titer tests, we observed that the accuracy of SMARTAI-LFA was maintained at over 99% while there was a significant decrease in human accuracy, indicating the reliable performance of SMARTAI-LFA. We envision a smartphone-based SMARTAI-LFA that allows continuously enhanced performance by adding clinical tests and satisfies the new criterion for digitalized real-time diagnostics.

Abstract Differential diagnosis of anaplastic thyroid carcinoma/poorly differentiated thyroid carcinoma (ATC/PDTC) from differentiated thyroid carcinoma (DTC) is crucial in patients with large thyroid malignancies. This study creates a predictive model using radiomics feature analysis to differentiate ATC/PDTC from DTC. We compared the clinicoradiological characteristics and radiomics features extracted from a volume of interest on contrast-enhanced computed tomography (CT) between the groups. Estimations of variable importance were performed via modeling using the random forest quantile classifier. The diagnostic performance of the model with radiomics features alone had the area under the receiver operating characteristic (AUROC) curve value of 0.883. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 81.7%, 93.3%, 97.7%, 64.5%, and 84.6%, respectively, for the differential diagnosis of ATC/PDTC and DTC. The model with both radiomics and clinicoradiological information showed the AUROC of 0.908, with sensitivity, specificity, PPV, NPV, and accuracy of 82.9%, 97.6%, 99.2%, 67.1%, and 86.5% respectively. Distant metastasis, moment, shape, age, and gray-level size zone matrix features were the most useful factors for differential diagnosis. Therefore, we concluded that a radiomics approach based on contrast-enhanced CT features can potentially differentiate ATC/PDTC from DTC in patients with large thyroid malignancies.

Lateral flow assays are valuable rapid diagnostic tests, but low sensitivity can hinder their precision. Here, the authors report an enrichment method using nanoporous AAO and red blood cell membranes, which when applied to patient samples prior to analysis can improve sensitivity up to 20-fold.

Background/Aims: Epstein-Barr virus (EBV) and Helicobacter pylori (HP) coinfection may synergistically induce severe inflammatory responses in the stomach tissue, increasing the risk of developing gastric cancer. We aimed to analyze the effect of EBV and HP coinfection on the clinicopathologic features and prognosis of gastric cancer, as well as to evaluate the role of EBV infection in non-gastric carcinoma with lymphoid stroma (non-GCLS).Methods: Overall, 956 patients who underwent surgery for gastric cancer between September 2014 and August 2015 were eligible and divided into groups, according to GCLS morphology, EBV infection, and HP infection. Clinicopathologic characteristics and oncologic outcomes were analyzed retrospectively.Results: EBV and HP coinfection was significantly associated with male sex, proximal location, GCLS morphology, and equivocal p53 expression (p

The apprenticeship-based training method (ABTM) is highly effective for gastrointestinal (GI) endoscopic training. However, the conventional ABTM has significant issues. Although many supplementary training methods (TMs) have been developed and utilized, they cannot entirely replace the ABTM, which remains the major TM strategy. Currently, new TM construction is crucial and necessary due to financial constraints, difficulty of obtaining sufficient training time due to patient safety-related regulations, and catastrophic damage caused by disasters such as the coronavirus disease 2019 pandemic. The simulator-based TM (SBTM) is widely accepted as an alternative to the ABTM, owing to the SBTM’s advantages. Since the 1960s, many GI endoscopy training simulators have been developed and numerous studies have been published on their effectiveness. While previous studies have focused on the simulator’s validity, this review focused on the accessibility of simulators that were introduced by the end of 2021. Although the current SBTM is effective in GI endoscopic education, extensive improvements are needed to replace the ABTM. Incorporating simulator-incorporated TMs into an improved ABTM is an attempt to overcome the incompleteness of the current SBTM. Until a new simulator is developed to replace the ABTM, it is desirable to operate a simulator-integrated and well-coordinated TM that is suitable for each country and institution.

Thermal damage and inflammatory responses of the sphincter and neurovascular bundles (NVBs) are responsible for post-prostatectomy incontinence and erectile dysfunction. Intraoperative hypothermia in the pelvic cavity may reduce the occurrence of these complications. We evaluated the feasibility of a novel rectal cooling system using an animal model. A novel rectal cooling system consisting of a cooling console and a multi-lumen rectal balloon was developed. We conducted animal tests on male pigs to evaluate the efficacy and safety of the system. The primary endpoint was to maintain the temperature of the NVBs at 25℃ (±5℃) during and after the electrocauterization of the bladder neck for 10 seconds. The safety endpoint was device-related complications or significant changes in the core body temperature of the pigs. The NVB temperature was below 30℃ within 3 minutes of activation of the rectal balloon. The temperature of the proximal NVB was consistently maintained below 25℃ in all cases. The temperature 1 cm from the bladder neck did not rise above 38°C and dropped to the initial level within 1 minute after electrocauterization. During cooling, the minimum temperature at the apex of the prostate was reduced to 10.1℃. There were no device-related complications or significant changes in core body temperature throughout the experiment. Animal tests suggest the feasibility and safety of this novel rectal cooling system. A first-in-human trial to assess the safety and efficacy of this system during radical prostatectomy is warranted.

Background: Studies of the prognostic role of circulating tumor cells (CTCs) in early- stage non-small cell lung cancer (NSCLC) are still limited. This study investigated the prognostic power of CTCs from the pulmonary vein (PV), peripheral blood (PB), and bone marrow (BM) for postoperative recurrence in patients who underwent curative resection for NSCLC. Methods: Forty patients who underwent curative resection for NSCLC were enrolled. Before resection, 10-mL samples were obtained of PB from the radial artery, blood from the PV of the lobe containing the tumor, and BM aspirates from the rib. A microfabricated filter was used for CTC enrichment, and immunofluorescence staining was used to identify CTCs. Results: The pathologic stage was stage I in 8 patients (20%), II in 15 (38%), III in 14 (35%), and IV in 3 (8%). The median number of PB-, PV-, and BM-CTCs was 4, 4, and 5, respectively. A time-dependent receiver operating characteristic curve analysis showed that PB-CTCs had excellent predictive value for recurrence-free survival (RFS), with the highest area under the curve at each time point (first, second, and third quartiles of RFS). In a multivariate Cox proportional hazard regression model, PB-CTCs were an independent risk factor for recurrence (hazard ratio, 10.580; 95% confidence interval, 1.637–68.388; p

Background/Aims The treatment of superficial esophageal neoplasms (SENs) in cirrhotic patients is challenging and rarely investigated. We evaluated the outcomes of endoscopic submucosal dissection (ESD) to determine the efficacy and safety of treating SENs in patients with liver cirrhosis. Methods The baseline characteristics and treatment outcomes of patients who underwent ESD for SENs between November 2005 and December 2017 were retrospectively reviewed. Results ESD was performed in 437 patients with 481 SENs, including 15 cirrhotic patients with 17 SENs. En bloc resection (88.2% vs. 97.0%) and curative resection (64.7% vs. 78.9%) rates were not different between the cirrhosis and non-cirrhosis groups (p=0.105 and p=0.224, respectively). Bleeding was more common in cirrhotic patients (p=0.054), and all cases were successfully controlled endoscopically. The median procedure and hospitalization duration did not differ between the groups. Overall survival was lower in cirrhotic patients (p=0.003), while disease-specific survival did not differ between the groups (p=0.85). Conclusions ESD could be a safe and effective treatment option for SENs in patients with cirrhosis. Detailed preprocedural assessments are needed, including determination of liver function, esophageal varix status, and remaining life expectancy, to identify patients who will obtain the greatest benefit.

Background/Aims: Postprocedural bleeding is known to be relatively low after argon plasma coagulation (APC) for gastric neoplasms; however, there are few studies proving the effect of antithrombotic agents. This study aimed to analyze the incidence of delayed bleeding (DB) based on antithrombotic agents administered and to identify the risk factors for DB in APC for gastric tumors. Methods: A total of 785 patients with 824 lesions underwent APC for single gastric neoplasm between January 2011 and January 2018. After exclusion, 719 and 102 lesions were classified as belonging to the non-antithrombotics (non-AT) and AT groups, respectively. The clinical outcomes were compared between the two groups, and we determined the risk factors for DB in gastric APC. Results: Of the total 821 cases, DB occurred in 20 cases (2.4%): 17 cases in the non-AT group and three cases in the AT group (2.4% vs 2.9%, p=0.728). Multivariate analysis of the risk factors for DB confirmed the following significant, independent risk factors: male sex (odds ratio, 7.66; 95% confidence interval, 1.02 to 57.69; p=0.048) and chronic kidney disease (odds ratio, 4.51; 95% confidence interval, 1.57 to 13.02; p=0.005). Thromboembolic events and perforation were not observed in all patients regardless of whether they took AT agents. Conclusions: AT therapy is acceptably safe in gastric APC because it does not significantly increase the incidence of DB. However, patients with chronic kidney disease or male sex need to receive careful follow-up on the incidence of post-APC bleeding.

Abstract Background Cancer stem cells (CSCs) are implicated in carcinogenesis, cancer progression, and recurrence. Several biomarkers have been described for pancreatic ductal adenocarcinoma (PDAC) CSCs; however, their function and mechanism remain unclear. Method In this study, secretome analysis was performed in pancreatic CSC-enriched spheres and control adherent cells for biomarker discovery. Glutaredoxin3 (GLRX3), a novel candidate upregulated in spheres, was evaluated for its function and clinical implication. Results PDAC CSC populations, cell lines, patient tissues, and blood samples demonstrated GLRX3 overexpression. In contrast, GLRX3 silencing decreased the in vitro proliferation, migration, clonogenicity, and sphere formation of cells. GLRX3 knockdown also reduced tumor formation and growth in vivo. GLRX3 was found to regulate Met/PI3K/AKT signaling and stemness-related molecules. ELISA results indicated GLRX3 overexpression in the serum of patients with PDAC compared to that in healthy controls. The sensitivity and specificity of GLRX3 for PDAC diagnosis were 80.0 and 100%, respectively. When GLRX3 and CA19–9 were combined, sensitivity was significantly increased to 98.3% compared to that with GLRX3 or CA19–9 alone. High GLRX3 expression was also associated with poor disease-free survival in patients receiving curative surgery. Conclusion Overall, these results indicate GLRX3 as a novel diagnostic marker and therapeutic target for PDAC targeting CSCs.

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

Background/Aims: Data regarding the prognosis of early esophageal cancer are lacking. This study investigated the long-term outcomes and factors affecting the survival of patients with mucosal esophageal squamous cell carcinoma (T1aESCC). Methods: We analyzed the clinical and tumor-specific parameters of 263 patients who received surgical resection (SR; n=63) or endoscopic resection (ER; n=200) for T1aESCC. Underlying comorbidities were scored using the Charlson comorbidity index (CCI). Overall survival (OS) was the primary outcome, and multivariate regression analysis was performed to predict factors for OS. Results: Of the study patients (age, 64.5±8.0 years), the CCI was 1.0±1.4 in the ER group and 0.6±0.9 in the SR group (p=0.107). The 5-year OS rate during follow-up (54.4±20.4 months) was 85.7% (ER group, 86.8%; SR group, 82.4%; p=0.631). The cumulative 5-year incidence of esophageal cancer recurrence was 10.5% in the ER group (vs 0% in the SR group). The overall mortality rate was 12.9% (ER group, 12.0%; SR group, 15.9%; p=0.399). The most common cause of mortality was second primary cancers in the ER group (75%) and organ dysfunction or postoperative complications in the SR group (70%). According to multivariate analysis, only CCI was significantly associated with OS (p2 and in those with a CCI ≤2 was 60.2% and 88.2%, respectively (p

Melanin is a brown or black pigment that protects skin from ultraviolet radiation and reactive oxygen species (ROS). However, overproduction of melanin is associated with lentigines, melasma, freckles and skin cancer. Licorice has shown antioxidant, anti-tumor, anti-platelet, anti-inflammatory and immunomodulatory activities and is used as a natural treatment for skin whitening. We aimed to confirm the potential of Wongam, a new cultivar of licorice developed by the Rural Development Administration (RDA), as a whitening agent in cosmetics. In addition, we verified the effect of heat treatment on the bioactivity of licorice by comparing antioxidant and anti-melanogenic activities of licorice extract before and after heating (130 °C). The heat-treated licorice extract (WH-130) showed higher radical-scavenging activities in the ABTS+ (2,2′-azino-bis-(3-ethylbenzothiazolin-6-sulfonic acid) diammonium salt) and DPPH (2,2-diphenyl-1-picrylhydrazyl) assays. In addition, WH-130 inhibited melanogenesis more effectively due to downregulation of tyrosinase in B16F10 melanoma cells than non-heated licorice extract. Moreover, heat treatment increased total phenolic content. In particular, isoliquiritigenin, an antioxidant and anti-melanogenic compound of licorice, was produced by heat treatment. In conclusion, WH-130, with increased levels of bioactive phenolics such as isoliquiritigenin, has potential for development into a novel skin whitening material with applications in cosmetics.

A sample preconcentration technique that exceeds a microfluidic device’s limited processing volume (up to microliters) is critical for real sample pretreatment applications. Here, we have developed a 3D-printed preconcentrator with a pillar structure (3DP2) to enrich the biological samples up to hundreds of microliter scales (700 μL) within 20 min by utilizing ion concentration polarization (ICP). We designed three-dimensional ready-to-pick reservoirs serially connected with a pillar-structured channel to enable large-volume preconcentration by balancing the preconcentrating forces (depletion, electrophoretic, and electroosmotic force) generated by ICP. Using the I-t and I-V curves, we confirmed that ICP performance was enhanced due to a pillar structure’s suppression of the vortex. Finally, we preconcentrated bovine serum albumin (BSA) and micro ribonucleic acid-21 (miRNA-21) two-fold. Moreover, depending on their size and charge, these were concentrated at different locations and could be extracted easily using pipettes. We believe that this study provides a novel strategy for downstream applications.

BackgroundPharmacovigilance using real-world data (RWD), such as multicenter electronic health records (EHRs), yields massively parallel adverse drug reaction (ADR) signals. However, proper validation of computationally detected ADR signals is not possible due to the lack of a reference standard for positive and negative associations. ObjectiveThis study aimed to develop a reference standard for ADR (RS-ADR) to streamline the systematic detection, assessment, and understanding of almost all drug-ADR associations suggested by RWD analyses. MethodsWe integrated well-known reference sets for drug-ADR pairs, including Side Effect Resource, Observational Medical Outcomes Partnership, and EU-ADR. We created a pharmacovigilance dictionary using controlled vocabularies and systematically annotated EHR data. Drug-ADR associations computed from MetaLAB and MetaNurse analyses of multicenter EHRs and extracted from the Food and Drug Administration Adverse Event Reporting System were integrated as “empirically determined” positive and negative reference sets by means of cross-validation between institutions. ResultsThe RS-ADR consisted of 1344 drugs, 4485 ADRs, and 6,027,840 drug-ADR pairs with positive and negative consensus votes as pharmacovigilance reference sets. After the curation of the initial version of RS-ADR, novel ADR signals such as “famotidine–hepatic function abnormal” were detected and reasonably validated by RS-ADR. Although the validation of the entire reference standard is challenging, especially with this initial version, the reference standard will improve as more RWD participate in the consensus voting with advanced pharmacovigilance dictionaries and analytic algorithms. One can check if a drug-ADR pair has been reported by our web-based search interface for RS-ADRs. ConclusionsRS-ADRs enriched with the pharmacovigilance dictionary, ADR knowledge, and real-world evidence from EHRs may streamline the systematic detection, evaluation, and causality assessment of computationally detected ADR signals.

Abstract We hypothesized that a deep-learning algorithm using HE images might be capable of predicting the benefits of adjuvant chemotherapy in cancer patients. HE slides were retrospectively collected from 1343 de-identified breast cancer patients at the Samsung Medical Center and used to develop the Lunit SCOPE algorithm. Lunit SCOPE was trained to predict the recurrence using the 21-gene assay (Oncotype DX) and histological parameters. The risk prediction model predicted the Oncotype DX score > 25 and the recurrence survival of the prognosis validation cohort and TCGA cohorts. The most important predictive variable was the mitotic cells in the cancer epithelium. Of the 363 patients who did not receive adjuvant therapy, 104 predicted high risk had a significantly lower survival rate. The top-300 genes highly correlated with the predicted risk were enriched for cell cycle, nuclear division, and cell division. From the Oncotype DX genes, the predicted risk was positively correlated with proliferation-associated genes and negatively correlated with prognostic genes from the estrogen category. An integrative analysis using Lunit SCOPE predicted the risk of cancer recurrence and the early-stage hormone receptor-positive breast cancer patients who would benefit from adjuvant chemotherapy.

Background/Aims The learning curve is essential in endoscopic submucosal dissection (ESD) training to improve outcomes and reduce the risk of procedure-related complications. We compared the outcomes of gastric ESD in live pigs performed by inexperienced endoscopists with or without ex vivo training. Materials and Methods At the Olympus Medical Training and Education Center, nine endoscopists inexperienced in ESD were randomly divided into two groups (group A: ex vivo training followed by in vivo training; group B: in vivo training only), and they performed gastric ESDs. Results A total of 18 ESDs were performed. The en bloc resection rate was 88.9% (16/18), and the complete resection rate was 94.4% (17/18). The median specimen size was 2.5 cm in group A and 2.1 cm in group B (P=0.227). There was no significant difference in the procedure time between the two groups, except for the marking time (0′58″ vs. 2′58″, P=0.027). However, group A took a shorter time in dissecting the same area than group B (109 vs. 246 sec/cm2, P=0.083). Complication rates were not significantly different between both groups. Conclusions The procedure time during in vivo ESD training in pigs may be shortened by prior ex vivo training. However, the ex vivo model presented poor air inflation, unstable fixation, and excessive mucosal hardness for cutting. An advanced simulator or sufficient ex vivo training may be effective in training for the ESD procedure.

The efficacy of the standard triple eradication regimen for Helicobacter pylori (H. pylori) infection is gradually decreasing due to increased antibiotic resistance of H. pylori, which is represented by clarithromycin resistance. This is an important issue for clinicians. Tailored therapies for H. pylori infection, including culture-based susceptibility testing and molecular methods detecting genetic mutations that increase resistance to antibiotics, have been introduced to overcome the high treatment failure rate of the standard triple regimen. The treatment results have been satisfactory. In addition to the H. pylori-related factors, the CYP2C19 gene polymorphism, in terms of host factors, affects the effectiveness of proton pump inhibitors. This article reviews the status of the tailored therapies for H. pylori infection along with the proven therapeutic effects and benefits of such treatments in Korea, where the resistance to antibiotics such as clarithromycin, metronidazole, and quinolone is prevalent.

Background/Aims: The coronavirus disease 2019 (COVID-19) outbreak caused numerous social and cultural changes, but few studies focused on their effects on gastroenterology (GI) fellowship training. This study evaluated the impact of COVID-19 on GI fellowship training. Methods: A web-based questionnaire was sent out to GI fellows in Korea between 15 February and 15 March 2021. The questionnaire included questions regarding the characteristics of GI fellows, perception of COVID-19 outbreak, impact of COVID-19 outbreak, and telemedicine on the education of a GI fellowship. Results: Among 111 answers, 94 respondents were analyzed. The GI fellows were provided with sufficient information about the COVID-19 outbreak (74.7%), well educated, and provided with personal protective equipment use (74.7% and 83.9%, respectively). On the other hand, outpatient schedule and volume decreased in 25.5% and 37.8% of respondents, respectively. Moreover, endoscopy sessions and volume decreased in 51.1% and 65.6% of respondents, respectively. As a result, 78.9% of respondents were concerned that the COVID-19 outbreak adversely affected their education. Telemedicine utilization was introduced during the COVID-19 outbreak, but only 20.0% and 10.6% of respondents agreed that telemedicine has benefits from the patient’s and doctor’s perspectives, respectively. In addition, only 25.9% of respondents were willing to continue telemedicine if adequately reimbursed, and 68.2% of respondents were concerned that it adversely affected their education. Conclusions: The COVID-19 outbreak has adversely affected GI fellowship training in Korea for outpatient clinics, gastrointestinal endoscopy, educational conferences, and telemedicine. This study highlights that GI fellowship training needs more attention in the COVID-19 outbreak.

Abstract As patients receiving definitive chemoradiotherapy (dCRT) for oesophageal squamous cell carcinoma (ESCC) are heterogeneous, we aimed to identify prognostic factors and failure patterns after dCRT. From 2006 to 2015, 327 patients who received dCRT for ESCC were reviewed. Treatment response to dCRT was evaluated based on EORTC‐PET criteria with endoscopy and CT results. After dCRT, 296 patients (90.5%) achieved disease stabilisation, with 132 cases of complete response (CR) (40.4%), 158 of partial response (PR) (48.3%) and 6 of stable disease (SD) (1.8%); 31 patients (9.5%) had progressive disease (PD). Median overall survival (OS) from response evaluation was 24.0 months in the overall population. Post‐treatment clinical response was the most significant prognostic factor for OS in the multivariate analysis (median OS, 65.0 months for CR, 17.3 months for PR, 4.4 months for SD and 4.0 months for PD; p

Abstract Diagnosis of occult palatine tonsil squamous cell carcinoma (SCC) using conventional magnetic resonance imaging (MRI) is difficult in patients with cervical nodal metastasis from an unknown primary site at presentation. We aimed to establish a radiomics approach based on MRI features extracted from the volume of interest in these patients. An Elastic Net model was developed to differentiate between normal palatine tonsils and occult palatine tonsil SCC. The diagnostic performances of the model with radiomics features extracted from T1-weighted image (WI), T2WI, contrast-enhanced T1WI, and an apparent diffusion coefficient (ADC) map had area under the receiver operating characteristic (AUROC) curve values of 0.831, 0.840, 0.781, and 0.807, respectively, for differential diagnosis. The model with features from the ADC alone showed the highest sensitivity of 90.0%, while the model with features from T1WI + T2WI + contrast-enhanced T1WI showed the highest AUROC of 0.853. The added sensitivity of the radiomics feature analysis were 34.6% over that of conventional MRI to detect occult palatine tonsil SCC. Therefore, we concluded that adding radiomics feature analysis to MRI may improve the detection sensitivity for occult palatine tonsil SCC in patients with a cervical nodal metastasis from cancer of an unknown primary site.

Effective screening of drugs to treat amyloid oligomeric aggregates associated with Alzheimer’s is needed for drug development. Here the authors report on the creation of an amyloid corona around a plasmonic nanoparticle to monitor amyloid degradation when exposed to potential drugs and demonstrate application.

Abstract Genetic variants causing underlying pharmacogenetic and disease phenotypes have been used as the basis for clinical decision-making. However, due to the lack of standards for next-generation sequencing (NGS) pipelines, reproducing genetic variants among institutions is still difficult. The aim of this study is to show how many important variants for clinical decisions can be individually detected using different pipelines. Genetic variants were derived from 105 breast cancer patient target DNA sequences via three different variant-calling pipelines. HaplotypeCaller, Mutect2 tumor-only mode in the Genome Analysis ToolKit (GATK), and VarScan were used in variant calling from the sequence read data processed by the same NGS preprocessing tools using Variant Effect Predictor. GATK HaplotypeCaller, VarScan, and MuTect2 found 25,130, 16,972, and 4232 variants, comprising 1491, 1400, and 321 annotated variants with ClinVar significance, respectively. The average number of ClinVar significant variants in the patients was 769.43, 16.50% of the variants were detected by only one variant caller. Despite variants with significant impact on clinical decision-making, the detected variants are different for each algorithm. To utilize genetic variants in the clinical field, a strict standard for NGS pipelines is essential.

Korean guidelines for nonsteroidal anti-inflammatory drug (NSAID)-induced peptic ulcer were previously developed in 2009 with the collaboration of the Korean College of Helicobacter and Upper Gastrointestinal Research and Korean Society of Gastroenterology. However, the previous guidelines were based mainly upon a review of the relevant literature and expert opinion. Therefore, the guidelines need to be revised. We organized a guideline Development Committee for drug-related peptic ulcer under the auspices of the Korean College of Helicobacter and Upper Gastrointestinal Research in 2017 and developed nine statements, including four for NSAIDs, three for aspirin and other antiplatelet agents, and two for anticoagulants through a de novo process founded on evidence-based medicine that included a literature search and a meta-analysis, A consensus was reached through the application of the modified Delphi method. The primary target of these guidelines is adult patients undergoing long-term treatment with NSAIDs, aspirin or other antiplatelet agents and anticoagulants. The revised guidelines reflect the expert consensus and is intended to assist clinicians in the management and prevention of druginduced peptic ulcer and associated conditions.

Background/Aims Percutaneous endoscopic gastrostomy (PEG) is usually performed on patients with chronic underlying diseases in the general ward (GW). This study evaluated the clinical outcomes of PEG performed on patients in the surgical intensive care unit (SICU) compared with those of PEG performed in the GW. Methods The medical records of 27 patients in the SICU and 263 in the GW, who underwent PEG between January 2013 and July 2017, were retrospectively reviewed. Results The median age of the 27 SICU patients was 66 years, and their median body mass index was 21.1 kg/m2. In the SICU group, the median baseline Sequential Organ Failure Assessment (SOFA) score was 4, and the median Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 16. The median interval between surgery and PEG in SICU patients was 30 days, with a PEG failure rate of 3.7%. Acute complications in SICU patients included bleeding (7.4%) and ileus (11.1%), while chronic complications included aspiration pneumonia (7.4%) and tube obstruction (3.7%). The rates of acute and chronic complications did not differ significantly between the SICU and GW groups. The 30-day mortality rate was 14.8% in SICU patients and 5.3% in GW patients (p=0.073). Conclusions PEG is a safe and feasible method of enteral feeding for critically ill patients who require ICU care after surgery.

Nonvariceal upper gastrointestinal bleeding (NVUGIB) refers to bleeding that develops in the gastrointestinal tract proximal to the ligament of Treitz. NVUGIB requires hospitalization and is associated with significant morbidity and mortality. Although European and Asian-Pacific guidelines have been published, there have been no previous guidelines regarding management of NVUGIB in Korea. Korea has a high prevalence of Helicobacter pylori infections, and patients have easy accessibility to endoscopy. Therefore, we believe that guidelines regarding management of NVUGIB in Korea are essential. The Korean Society of Gastroenterology reviewed the recent evidence and recommends practical management guidelines on NVUGIB in Korea.

The Korean guidelines for nonsteroidal anti-inflammatory drug (NSAID)-induced peptic ulcers were previously developed under co-work with the Korean College of Helicobacter and Upper Gastrointestinal Research and Korean Society of Gastroenterology at 2009. On the other hand, the previous guidelines were based mainly on a literature review and expert opinions. Therefore, the guidelines need to be revised. In this study, a guideline development committee for drug-induced peptic ulcers was organized under the Korean College of Helicobacter and Upper Gastrointestinal Research in 2017. Nine statements were developed, including four for NSAID, three for aspirin and other antiplatelet agents, and two for anticoagulants through de novo processes based on evidence-based medicine, such as a literature search, meta-analysis, and the consensus was established using the modified Delphi method. The primary target of this guideline was adult patients taking long-term NSAIDs, aspirin, or other antiplatelet agent and anticoagulants. The revised guidelines reflect the consensus of expert opinions and are intended to assist relevant clinicians in the management and prevention of drug-induced peptic ulcers and associated conditions.

Abstract Background Artemisia in East Asia includes a number of economically important taxa that are widely used for food, medicinal, and ornamental purposes. The identification of taxa, however, has been hampered by insufficient diagnostic morphological characteristics and frequent natural hybridization. Development of novel DNA markers or barcodes with sufficient resolution to resolve taxonomic issues of Artemisia in East Asia is significant challenge. Results To establish a molecular basis for taxonomic identification and comparative phylogenomic analysis of Artemisia, we newly determined 19 chloroplast genome (plastome) sequences of 18 Artemisia taxa in East Asia, de novo-assembled and annotated the plastomes of two taxa using publicly available Illumina reads, and compared them with 11 Artemisia plastomes reported previously. The plastomes of Artemisia were 150,858–151,318 base pairs (bp) in length and harbored 87 protein-coding genes, 37 transfer RNAs, and 8 ribosomal RNA genes in conserved order and orientation. Evolutionary analyses of whole plastomes and 80 non-redundant protein-coding genes revealed that the noncoding trnH-psbA spacer was highly variable in size and nucleotide sequence both between and within taxa, whereas the coding sequences of accD and ycf1 were under weak positive selection and relaxed selective constraints, respectively. Phylogenetic analysis of the whole plastomes based on maximum likelihood and Bayesian inference analyses yielded five groups of Artemisia plastomes clustered in the monophyletic subgenus Dracunculus and paraphyletic subgenus Artemisia, suggesting that the whole plastomes can be used as molecular markers to infer the chloroplast haplotypes of Artemisia taxa. Additionally, analysis of accD and ycf1 hotspots enabled the development of novel markers potentially applicable across the family Asteraceae with high discriminatory power. Conclusions The complete sequences of the Artemisia plastomes are sufficiently polymorphic to be used as super-barcodes for this genus. It will facilitate the development of new molecular markers and study of the phylogenomic relationships of Artemisia species in the family Asteraceae.

Non-variceal upper gastrointestinal bleeding (NVUGIB) refers to bleeding that develops in the gastrointestinal tract proximal to the ligament of Treitz. NVUGIB is an important cause for visiting the hospital and is associated with significant morbidity and mortality. Although European and Asian-Pacific guidelines have been published, there has been no previous guidelines regarding management of NVUGIB in Korea. Korea is a country with a high prevalence of Helicobacter pylori infection and patients have easy accessibility to receive endoscopy. Therefore, we believe that guidelines regarding management of NVUGIB are mandatory. The Korean Society of Gastroenterology reviewed recent evidence and recommends practical management guidelines on NVUGIB in Korea.

Abstract Background The association between Helicobacter pylori and reflux esophagitis (RE) remains controversial. This study aimed to prospectively evaluate the effect of H. pylori eradication on RE and gastroesophageal reflux (GERD) symptoms in H. pylori-positive patients who underwent endoscopic resection of gastric neoplasm. Methods Of the 244 patients enrolled in this study, 173 H. pylori-positive patients underwent follow-up at least once. We evaluated the prevalence of RE and GERD symptoms in these patients following H. pylori eradication. Results There were 75.7% (131/173), 78.6% (125/159), and 78.9% (105/133) subjects who were successfully eradicated after 6, 12, and 18–24 months, respectively. During the 2-year follow-up period, the eradication of H. pylori did not increase the incidence of RE (OR 0.93; 95% CI, 0.49–1.77, p = 0.828). H. pylori status was also not associated with the development of GERD symptoms (OR 1.12; 95% CI, 0.47–2.95, p = 0.721). In the univariate analysis for RE, present smoking history (OR 4.79; 95% CI 1.98–11.60, p = 0.001), present alcohol consumption history (OR 2.18; 95% CI 1.03–4.63, p = 0.041), and diabetes mellitus (OR 2.44; 95% CI 1.02–5.86, p = 0.045) were found to be associated with RE. Multivariate analysis showed that present smoking history (OR 4.54; 95% CI 1.84–11.02, p = 0.001) was a significant risk factor for RE. Conclusions H. pylori eradication did not increase the incidence of RE or GERD symptoms in patients who underwent endoscopic resection of gastric neoplasm.

Background/AimsAlthough acid suppressants are widely used for the prevention or treatment of drug-induced upper gastrointestinal bleeding (GIB), evidence regarding the prevention of anticoagulant-related GIB is scarce. The aim of this study was to evaluate the protective effect of acid suppressants against anticoagulant-related GIB.Methods : A systematic review was conducted of studies that evaluated the protective effect of acid suppressants against anticoagulant-related GIB found in PubMed, the Cochrane library, Embase, and KoreaMed from the date of database inception to April 2018. Random effect model meta-analyses with sensitivity analyses were conducted. The methodological quality of each included publication was evaluated using the Risk of Bias Assessment Tool for Nonrandomized Studies. Publication bias was assessed.Results : In total, six nested case-control or cohort studies were identified and analyzed. Proton-pump inhibitors (PPI) had a protective effect against upper GIB in patients on dicumarinics (risk ratio [RR], 0.56; 95% confidence interval [CI], 0.38 to 0.83; I2, 0%); however, the histamine-2 receptor antagonist did not have the same effect (RR, 0.97; 95% CI, 0.52 to 1.81; I2, 0%). Acid suppressants did not have a protective effect against GIB in patients on dabigatran (hazard ratio, 0.78; 95% CI, 0.44 to 1.37; I2, 81.8%).Conclusion : sThe protective effect of PPIs against dicumarinics-related upper GIB was clear, while there was no evidence supporting the protective effect of acid suppressants against dabigatran-related GIB. However, in the absence of randomized trials demonstrating a lack of bias, solid conclusions cannot be drawn.

The training and education of GI fellows are crucial issues for the training institutions and academic societies. Current circumstances about GI fellows are changing rapidly according to shortage of training period of the internal medicine residency program and growing up of multimedia and web-based education system. Recently, the education board of Korean Society of Gastroenterology revised the educational objectives considering 2 years program of GI fellows. We also need to develop a concrete education program through cooperation with related organizations including the training institutions and academic societies. All of these efforts should be made with the goal of making a good gastroenterologist, not just making an endoscopist.

A thorough disinfection and infection control process associated with gastrointestinal endoscopy is highly important for the health and safety of the examinee and the medical staff involved in the procedure. Endoscopic reprocessing and disinfection are two of the most important steps in quality control of endoscopy. In 2019, the Korean Society of Gastrointestinal Endoscopy updated the Accreditation of Qualified Endoscopy Unit assessment items for these quality indicators. Assessment of disinfection and infection control comprises 28 mandatory items in the categories of disinfection education, pre-cleaning, cleaning, disinfection, rinsing, drying, reprocessing, storage, endoscopic accessories, water bottle and connectors, space/facilities, personal protective equipment, disinfection ledger, and regulations regarding infection control and disinfection. The updated Accreditation of Qualified Endoscopy Unit assessment items are useful for improving the quality of endoscopy by ensuring thorough inspection of endoscopic disinfection and infection control.

Abstract An essential requirement for bio/chemical sensors and electronic nose systems is the ability to detect the intended target at room temperature with high selectivity. We report a reduced graphene oxide (rGO)-based gas sensor functionalized with a peptide receptor to detect dinitrotoluene (DNT), which is a byproduct of trinitrotoluene (TNT). We fabricated the multi-arrayed rGO sensor using spin coating and a standard microfabrication technique. Subsequently, the rGO was subjected to photolithography and an etching process, after which we prepared the DNT-specific binding peptide (DNT-bp, sequence: His-Pro-Asn-Phe-Se r-Lys-Tyr-IleLeu-HisGln-Arg-Cys) and DNT non-specific binding peptide (DNT-nbp, sequence: Thr-Ser-Met-Leu-Leu-Met-Ser-Pro-Lys-His-Gln-Ala-Cys). These two peptides were prepared to function as highly specific and highly non-specific (for the control experiment) peptide receptors, respectively. By detecting the differential signals between the DNT-bp and DNT-nbp functionalized rGO sensor, we demonstrated the ability of 2,4-dinitrotoluene (DNT) targets to bind to DNT-specific binding peptide surfaces, showing good sensitivity and selectivity. The advantage of using the differential signal is that it eliminates unwanted electrical noise and/or environmental effects. We achieved sensitivity of 27 ± 2 × 10−6 per part per billion (ppb) for the slope of resistance change versus DNT gas concentration of 80, 160, 240, 320, and 480 ppm, respectively. By sequentially flowing DNT vapor (320 ppb), acetone (100 ppm), toluene (1 ppm), and ethanol (100 ppm) onto the rGO sensors, the change in the signal of rGO in the presence of DNT gas is 6400 × 10−6 per ppb whereas the signals from the other gases show no changes, representing highly selective performance. Using this platform, we were also able to regenerate the surface by simply purging with N2.

Achieving stable trotting of quadruped robots on various surfaces is challenging because they lose balance due to the displacement of their center of gravity (COG) and undesirable impulse forces. This paper proposes schemes for postural transition and robust posture control, thus enabling quadruped robots to trot on horizontal and slanted surfaces. For a region connected by surfaces with different angles, the postural transition scheme (PTS) is implemented by the movement values optimized by a real-coded genetic algorithm (RCGA), which regulates the location of the center of gravity (COG) projection point of robots. In addition, the movement values are applied to the center points of the desired foot trajectories by using cubic polynomial, which is able to generate adaptive foot motion continuously and gradually. For robust posture control, admittance control with impedance modulation (IM) is applied to the foot trajectories, which changes the impedance parameters in real-time depending on the magnitude of the disturbances, such as the excessive swaying of the robot body that cause instabilities in the robot posture during locomotion. Control thresholds regulated by the angular speed of the robot body are proposed as a criterion for controlling the excessive swaying by IM. Computer simulations and hardware experiments were carried out to verify the performance of the proposed schemes.

There is a growing interest in gastroenterology and hepatology fellowship training in Korea and other countries. The Korean Society of Gastroenterology held an international symposium for gastroenterology and hepatology fellowship training, titled, GI Fellow Training in Asia-Pacific Countries on April 14, 2018. The Japanese education system was different for each hospital. The American societies for gastroenterology set up their education system together and have continued with frequent modification. The Taiwan and Singapore education systems are well organized and localized. We need a well-organized and sustainable education system for gastroenterology and hepatology fellowship training suitable for Korea.