Background/Aims: Endoscopic ultrasound-guided fine-needle aspiration/biopsy (EUS-FNA/B) is essential in diagnosing solid pancreatic lesions (SPLs), but without rapid on-site evaluation (ROSE), a repeat EUS-FNA/B is crucial for clarifying an inconclusive diagnosis. We aimed to evaluate factors associated with improved diagnostic performance of repeat EUS-FNA/B for initially inconclusive SPL diagnoses without ROSE. Methods: Of 5,894 patients subjected to EUS-FNA/B, 237 (4.0%) with an initially inconclusive diagnosis of SPLs were retrospectively enrolled from five tertiary medical centers between January 2016 and June 2021. Diagnostic performance and procedural factors of EUS-FNA/B were analyzed. Results: The diagnostic accuracies of first and repeat EUS-FNA/B were 96.2% and 67.6%, respectively. Of 237 patients with an inconclusive diagnosis from initial EUS-FNA/B, 150were pathologically diagnosed after repeat EUS-FNA/B. In multivariate analysis of repeat EUS-FNA/B, tumor location (body/tail vs head: odds ratio [OR], 3.74; 95% confidence inter-val [CI], 1.48 to 9.46), number of needle passes (≥4 vs ≤3: OR, 4.80; 95% CI, 1.44 to 15.99),needle type (FNB vs FNA: OR, 3.26; 95% CI, 1.44 to 7.36), needle size (22 gauge vs 19/20 gauge: OR, 2.35; 95% CI, 1.19 to 4.62), and suction method (suction vs others: OR, 5.19;95% CI, 1.30 to 20.75) were associated with a significantly improved diagnostic performance. Conclusions Repeat EUS-FNA/B is essential for patients with an inconclusive EUS-FNA/B without ROSE. To improve the diagnostic performance of repeated EUS-FNA/B, it is recom-mended that 22-gauge FNB needles, ≥4 needle passes, and suction methods are used.

Purpose: Cannulation of the major papilla is the most challenging part of endoscopic retrograde cholangiopancreatography (ERCP) for which physician-controlled wire-guided cannulation (PCWGC) and assistant-controlled wire-guided cannulation (ACWGC) are used as the cannulation techniques. PCWGC can reportedly save up to about 30% of the labor cost by reducing the number of assistants. This study aims to compare the safety and efficacy of PCWGC and ACWGC. Materials and Methods: Of the 2151 patients aged >20 years (4193 cases) who underwent ERCP at Yonsei University Medical Center between January 2015 and December 2016, 989 were included in this study. Results: Among efficacy outcomes, cannulation success rate, rate of precut sphincterotomy (PCWGC vs. ACWGC: 21.3% vs.25.9%), bile duct cannulation time (PCWGC vs. ACWGC: median 3.0 minutes vs. 3.6 minutes), and total procedure time (PCWGC vs. ACWGC: median 13.6 minutes vs. 13.1 minutes) were not significantly different. Among safety outcomes, lower rates of postERCP pancreatitis were observed with PCWGC than with ACWGC (PCWGC vs. ACWGC: 5.8% vs. 8.8%, p=0.128). Among other post-ERCP adverse events (bleeding, perforation, and cholangitis), the difference was not significant between the groups. Radiation exposure (total dose area product, PCWGC vs. ACWGC: median 1979.9 µGym2 vs. 2062.0 µGym2 , p=0.194) and ERCP cost excluding labor cost (PCWGC vs. ACWGC: $1576 vs. $1547, p=0.606) were not significantly different. Conclusion Requiring less assistants, PCWGC showed comparable efficacy and safety to ACWGC. PCWGC can be considered as an alternative option, especially in facilities lacking manpower and resources.

Background/Aims: Programmed death-ligand 1 (PD-L1) expression in tumor cells is associated with a poor biliary tract cancer (BTC) prognosis; tumor-infiltrating immune cells in the tumor microenvironment are associated with a better prognosis. The effect of PD-L1 expression on immune cells on survival is unclear. We investigated the relationship between PD-L1 expression in immune cells and BTC prognosis. Methods: PD-L1 expression was evaluated using an anti-PD-L1 22C3 mouse monoclonal primary antibody, and its relationships with clinical characteristics and prognosis were analyzed using the Cox proportional hazard model to investigate the prognostic performance of PD-L1 in BTC. Results: Among 144 analyzed cases, patients with positive PD-L1 expression in tumor cells and negative PD-L1 expression in immune cells showed poorer overall survival rates than those exhibiting other expressions (tumor cells: hazard ratio [HR]=1.023, p<0.001; immune cells: HR=0.983, p=0.021). PD-L1 expression in tumor cells was an independent predictor of poor overall survival (HR=1.024, p<0.001). In contrast, PD-L1 expression in immune cells was a predictive marker of good prognosis (HR=0.983, p=0.018). Conclusions PD-L1 expression in immune cells may be used as an independent factor to evaluate the prognosis of patients with BTC.

Background: Advances in neuroscience and neurotechnology provide great benefits to humans though unknown challenges may arise. We should address these challenges using new standards as well as existing ones. Novel standards should include ethical, legal, and social aspects which would be appropriate for advancing neuroscience and technology.Therefore, the Korea Neuroethics Guidelines were developed by stakeholders related to neuroscience and neurotechnology, including experts, policy makers, and the public in the Republic of Korea.Method: The guidelines were drafted by neuroethics experts, were disclosed at a public hearing, and were subsequently revised by opinions of various stakeholders. Results: The guidelines are composed of twelve issues; humanity or human dignity, individual personality and identity, social justice, safety, sociocultural prejudice and public communication, misuse of technology, responsibility for the use of neuroscience and technology, specificity according to the purpose of using neurotechnology, autonomy, privacy and personal information, research, and enhancement. Conclusion Although the guidelines may require a more detailed discussion after future advances in neuroscience and technology or changes in socio-cultural milieu, the development of the Korea Neuroethics Guidelines is a milestone for the scientific community and society in general for the ongoing development in neuroscience and neurotechnology.

Objectives: This study aimed to examine the correlations between the regional characteristics of counties in Gangwon Province, Republic of Korea and the ratio of intracounty to extracounty sources of coronavirus disease 2019 (COVID-19) infection. Methods: The region of the infectious contact was analysed for each COVID-19 case reported in Gangwon Province between February 22, 2020 and February 7, 2022. The population, population density, area, the proportion of urban residents, the proportion of older adults (>65 years), financial independence, and the number of adjacent counties were assessed for each of the 18 counties in Gangwon Province. Correlation coefficients between regional characteristics and the ratio of intracounty to extracounty infections were calculated. Results: In total, 19,645 cases were included in this study. The population, population density, proportion of older adults, and proportion of urban residents were significantly correlated with the ratio of intracounty to extracounty infections. A stratified analysis with an age cut-point of 65 years showed that the proportion of older adults had a significant negative correlation with the ratio of intracounty to extracounty infections. In other words, the proportions of extracounty infections were higher in countries with higher proportions of older adults. Conclusion Regions with ageing populations should carefully observe trends in infectious disease outbreaks in other regions to prevent possible transmission.

Purpose: Hypoxaemia is a significant adverse event during endoscopic retrograde cholangiopancreatography (ERCP) under monitored anaesthesia care (MAC); however, no model has been developed to predict hypoxaemia. We aimed to develop and compare logistic regression (LR) and machine learning (ML) models to predict hypoxaemia during ERCP under MAC. Materials and Methods: We collected patient data from our institutional ERCP database. The study population was randomly divided into training and test sets (7:3). Models were fit to training data and evaluated on unseen test data. The training set was further split into k-fold (k=5) for tuning hyperparameters, such as feature selection and early stopping. Models were trained over k loops; the i-th fold was set aside as a validation set in the i-th loop. Model performance was measured using area under the curve (AUC). Results: We identified 6114 cases of ERCP under MAC, with a total hypoxaemia rate of 5.9%. The LR model was established by combining eight variables and had a test AUC of 0.693. The ML and LR models were evaluated on 30 independent data splits. The average test AUC for LR was 0.7230, which improved to 0.7336 by adding eight more variables with an l 1 regularisation-based selection technique and ensembling the LRs and gradient boosting algorithm (GBM). The high-risk group was discriminated using the GBM ensemble model, with a sensitivity and specificity of 63.6% and 72.2%, respectively. Conclusion We established GBM ensemble model and LR model for risk prediction, which demonstrated good potential for preventing hypoxaemia during ERCP under MAC.

Background/Aims: Controversy regarding the effectiveness of neoadjuvant therapy for resectable pancreatic ductal adenocarcinoma (PDAC) still exists. Here, we aimed to identify the potential benefits of neoadjuvant therapy followed by surgery for resectable PDAC. Methods: We reviewed radiologically resectable PDAC patients who received resection with curative intent at a tertiary hospital in South Korea between January 2012 and August 2019. A total of 202 patients underwent curative resection for resectable PDAC: 167 underwent surgical resection first during this period, and 35 received neoadjuvant chemotherapy/chemoradiation therapy followed by surgery. Resectable PDAC patients were subdivided, and 1:3 propensity score matching (PSM) was performed to reduce selection bias. Results: Compared with the group that received surgery first, the group that received neoadjuvant treatment followed by surgery had significantly smaller tumors (22.0 mm vs 27.0 mm, p=0.004), a smaller proportion of patients with postoperative pathologic T stage (p=0.026), a smaller proportion of patients with lymphovascular invasion (20.0% vs 40.7%, p=0.022), and a larger proportion of patients with negative resection margins (74.3% vs 51.5%, p=0.049). After PSM, the group that received neoadjuvant therapy had a significantly longer progression-free survival than those in the group that underwent surgery first (29.6 months vs 15.1 months, p=0.002). Overall survival was not significantly different between the two groups after PSM analysis. Conclusions We observed significantly better surgical outcomes and progression-free survival with the addition of neoadjuvant therapy to the management of resectable PDAC. However, despite PSM, there was still selection bias due to the use of different regimens between the groups receiving surgery first and neoadjuvant therapy. Large homogeneous samples are needed in the future prospective studies.

Mitral regurgitation (MR) is the most common heart disease in small-breed dogs. Mitral repair, which comprise artificial chorda tendineae implantation and mitral annuloplasty, has become the mainstay of treatment in the veterinary field. We report on two small dogs who underwent mitral repair surgery for MR. A Hegar dilator was used during mitral annuloplasty for accurate and reproducible surgery. In both cases, mitral regurgitant flow almost disappeared after surgery, and clinical signs improved. The treatment regimen was terminated 3 months after the surgery. We concluded that using a Hegar dilator may facilitate mitral valve repair surgery.

In February 2018, the Withdrawal of the Life-sustaining Treatment (WLST) Decision Act was legalized in Korea. Donation after circulatory death (DCD) after WLST was classified as DCD category III. We report the first case of successful organ donation after WLST in Korea. A 52-year-old male who experienced cerebral hemorrhage was a potential brain-dead donor with donation consent. During the first brain death examination, Babinski reflex was present, which disappeared two days later. Then, electroencephalography was performed five times at intervals of 2 to 3 days, according to the recommendation of a neurologist.The patient was transferred to the OR at 19:30 July 3, 2020. At 20:00, an intensive care unit specialist performed extubation and discontinued vasopressors. Oxygen saturation fell to < 70% in 1 minute, which signaled the beginning of functional warm ischemia. At 20:15, asystole was confirmed; after 5 minutes of “no-touch time,” circulatory death was declared.Organ procurement surgery was initiated, with surgeons performing the recipient surgery ready in the adjacent OR. Through the first successful DCD case, we expected that DCD will be actively implemented in Korea, saving the lives of patient waiting for transplantation and resolving the imbalance between organ receipt and donation.

In February 2018, the Withdrawal of the Life-sustaining Treatment (WLST) Decision Act was legalized in Korea. Donation after circulatory death (DCD) after WLST was classified as DCD category III. We report the first case of successful organ donation after WLST in Korea. A 52-year-old male who experienced cerebral hemorrhage was a potential brain-dead donor with donation consent. During the first brain death examination, Babinski reflex was present, which disappeared two days later. Then, electroencephalography was performed five times at intervals of 2 to 3 days, according to the recommendation of a neurologist.The patient was transferred to the OR at 19:30 July 3, 2020. At 20:00, an intensive care unit specialist performed extubation and discontinued vasopressors. Oxygen saturation fell to < 70% in 1 minute, which signaled the beginning of functional warm ischemia. At 20:15, asystole was confirmed; after 5 minutes of “no-touch time,” circulatory death was declared.Organ procurement surgery was initiated, with surgeons performing the recipient surgery ready in the adjacent OR. Through the first successful DCD case, we expected that DCD will be actively implemented in Korea, saving the lives of patient waiting for transplantation and resolving the imbalance between organ receipt and donation.