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An air-sea interaction field campaign was conducted in September of 2017 within the warm and cold eddy region of the western Northwest Pacific (WNP) (17.5˚-20.5˚N, 127.5˚E-133.5˚E). Both near-surface oceanic and atmospheric conditions in addition to ocean heat content (OHC) were examined to better understand the mechanisms governing high heat flux magnitudes responsible for rapidly intensifying tropical cyclones. Observations from this experiment indicate that the latent heat flux (LHF) under modest wind conditions reached 400 W m-2 within the vicinity of a warm eddy, with OHC higher than 100 kJ cm-2 of warm eddy region being 2~3 times as large as that of cold eddy region. These high OHC and a resultant high LHF in the warm eddy, comparable to the magnitude of LHF in the North Equatorial Current, may explain the mechanism of why tropical cyclones over a warm eddy in eddy-rich zones often rapidly intensify in the WNP. A month later typhoon Lan rapidly intensified into a super typhoon, while passing over the boundary region of warm and cold eddies during the observation period. Results from this study illustrate that both the wind-normalized LHF and the difference (Qs-Qa) between the specific humidity at air (Qa) and at the sea surface (Qs), closely correlate with OHC patterns, which suggests that the ocean looks likely to control the spatial pattern of LHF. Overall, both the ocean and weather conditions govern the pattern of specific humidity difference between the air-sea interface, with large OHC over the warm eddy controlling higher Qs and the pattern of Qa depending on the pattern of wind direction. Qa as a factor impacting LHF magnitude is strongly linked to wind direction in the experimental area, that is, the drier northwesterly flow and southeasterly moist wind, resulting in the enhanced contrast of specific humidity at cold eddy region.

In this study, a machine learning (ML)-based Tropical Cyclones (TCs) Rapid Intensification (RI) prediction model has been developed by using the Net Energy Gain Rate Index (NGR). This index realistically captures the energy exchanges between the ocean and the atmosphere during the intensification of TCs. It does so by incorporating the thermal conditions of the upper ocean and using an accurate parameterization for sea surface roughness. To evaluate the effectiveness of NGR in enhancing prediction accuracy, five distinct ML algorithms were utilized: Decision Tree, Logistic Regression, Support Vector Machine, K-Nearest Neighbors, and Feed-forward Neural Network. Two sets of experiments were performed for each algorithm. The first set used only traditional predictors, while the second set incorporated NGR. The outcomes revealed that models trained with the inclusion of NGR exhibited superior performance compared to those that only used traditional predictors. Additionally, an ensemble model was developed by utilizing a hard-voting method, combining the predictions of all five individual algorithms. This ensemble approach showed a noteworthy improvement of approximately 10% in the skill score of RI prediction when NGR was included. The findings of this study emphasize the potential of NGR in refining TC intensity prediction and underline the effectiveness of ensemble ML models in RI event detection.

Information about wind variations and future wind conditions is essential for a monsoon domain such as the Northwest Pacific (NWP) region. This study utilizes 10 Generalized Circulation Models (GCM) from CMIP6 to evaluate near-future wind changes in the NWP under various climate warming scenarios. Evaluation against the ERA5 reanalysis dataset for the historical period 1985–2014 reveals a relatively small error with an average of no more than 1 m/s, particularly in the East Asian Marginal Seas (EAMS). Future projections (2026–2050) indicate intensified winds, with a 5–8% increase in the summer season in the EAMS, such as the Yellow Sea, East Sea, and East China Sea, while slight decreases are observed in the winter period. Climate mode influences show that winter El Niño tends to decrease wind speeds in the southern study domain, while intensifying winds are observed in the northern part, particularly under SSP5-8.5. Conversely, summer El Niño induces higher positive anomalous wind speeds in the EAMS, observed in SSP2-4.5. These conditions are likely linked to El Niño-induced SST anomalies. For the application of CMIP6 surface winds, the findings are essential for further investigations focusing on the oceanic consequences of anticipated wind changes such as the ocean wave climate, which can be studied through model simulations.

The air-sea drag coefficient (Cd) is closely related to tropical cyclone (TC) intensification. Several recent studies suggested that the Cd decreases in winds greater than 33 m s−1. The effects of Cd reduction in high winds on TC intensity, especially rapid intensification (RI) and the lifetime maximum intensity (LMI) distribution, were investigated by analyzing the wind-dependent Cd-based ocean vertical mixing and the energy budget. In addition, to consider the uncertainty of the Cd in extreme winds (above 50 m s−1), three types of Cd fitting that decrease after 33 m s−1, which show different trends after 50 m s−1 (increase, flat, and decrease), were adopted. The results were then compared with those for the control fitting (saturated after 33 m s−1) and show that the reduced Cd in high winds drives an increase in net energy by reducing frictional dissipation and suppressing sea surface cooling. This extra energy prevents the TC from achieving a steady-state, causing the bimodality of simulated maximum potential intensity. The observed steady-state probability (intensification rate and RI probability) in the Cd reduced wind range were significantly lower (higher) than in the others. These results suggest that Cd reduction might potentially induce the RI and LMI bimodality.

The East Sea (ES; Sea of Japan) meridional overturning circulation (MOC) serves as a crucial mechanism for the transportation of dissolved, colloidal, and suspended particulate matters, including pollutants, on the surface to deep waters via thermohaline circulation. Therefore, understanding the structure of the ES MOC is critical for characterizing its temporal and spatial distribution. Numerous studies have estimated these parameters indirectly using chemical tracers, severely limiting the accuracy of the results. In this study, we provide a method for directly estimating the turnover times of the ES MOC using the stream functions calculated from HYbrid Coordinate Ocean Model (HYCOM) reanalysis data by averaging the flow pattern in the meridional 2-D plane. Because the flow pattern is not consistent but various over time, three cases of stream function fields were computed over a 20-year period. The turnover time was estimated by calculating the time required for water particles to circulate along the streamlines. In the cases of multiple (two or three) convection cells, we considered all possible scenarios of the exchange of water particles between adjacent cells, so that they circulated over those cells until finally returning to the original position and completing the journey on the ES MOC. Three different cell cases were tested, and each case had different water particle exchange scenarios. The resulting turnover times were 17.91–58.59 years, 26.41–37.28 years, and 8.68–45.44 years for the mean, deep, and shallow convection cases, respectively. The maximum turnover time, namely 58.59 years, was obtained when circulating the water particle over all three cells, and it was approximately half of that estimated by the chemical tracers in previous studies (∼100 years). This underestimation arose because the streamlines and water particle movement were not calculated in the shallow (3,000 m) in this study. Regardless, the results of this study provide insight into the ES MOC dynamics and indicate that the traditional chemical turnover time represents only one of the various turnover scenarios that could exist in the ES.

The National Typhoon Center of the Korea Meteorological Administration developed a statistical–dynamical typhoon intensity prediction model for the western North Pacific, the CSTIPS-DAT, using a track-pattern clustering technique. The model led to significant improvements in the prediction of the intensity of tropical cyclones (TCs). However, relatively large errors have been found in a cluster located in the tropical western North Pacific (TWNP), mainly because of the large predictand variance. In this study, a decision-tree algorithm was employed to reduce the predictand variance for TCs in the TWNP. The tree predicts the likelihood of a TC reaching a maximum lifetime intensity greater than 70 knots at its genesis. The developed four rules suggest that the pre-existing ocean thermal structures along the track and the latitude of a TC’s position play significant roles in the determination of its intensity. The developed decision-tree classification exhibited 90.0% and 80.5% accuracy in the training and test periods, respectively. These results suggest that intensity prediction with the CSTIPS-DAT can be further improved by developing independent statistical models for TC groups classified by the present algorithm.

The interannual variability of winter sea levels averaged over the northeast Asian marginal seas, consisting of the Yellow Sea, East China Sea, and the East Sea (ES), was investigated. The spatial-mean sea level in winter observed using satellite altimetry shows significant interannual variations with a long-term rising trend of 3.88 mm y−1 during 1993–2017, with relatively high (Period H) and low (Period L) sea level anomalies. These anomalies correlate with the patterns of the East Asian winter monsoon at interannual timescales. The atmospheric pressure difference between the Sea of Okhotsk (SO) and ES around the Soya Strait is large during Period H. Ekman transport increases due to enhanced southeastward wind stress and results in a horizontal mass convergence that yields positive sea level anomalies during Period H. In contrast, the wind-induced transport is enhanced in the southern ES rather than in the southern SO resulting in horizontal mass divergence and negative anomalies in the spatial-mean winter sea level during Period L. Our results highlight the important roles of local wind forcing and Ekman dynamics in inducing interannual winter sea level variability in the region indicating the high predictive ability of atmospheric pressure anomalies around the Soya Strait.

Monthly mean sea-levels have annual maxima in August in the northeast Asian marginal seas (NEAMS). Based on satellite altimetry data, the rising rate of the August NEAMS sea-level (ANS, 4.2 mm∙yr−1) is greater than those of the NEAMS (3.6 mm∙yr−1) and global (3.4 mm∙yr−1) annual mean sea-levels. Thus, the interannual variations of ANS are classified as relatively high (period H) and low (period L) years and have been analysed because of the high risk of sea-level fluctuation to the coastal regions in August. In period H, there are large atmospheric pressure gradients between the high pressure zone in the Kuroshio Extension (KE) and the low pressure zone in the west of Taiwan (WT). In period L, the atmospheric pressure gradients are small between the above-mentioned zones. Large atmospheric pressure gradients induce strong west-northwestward wind stresses and more Ekman transport from the northwest Pacific Ocean into the NEAMS. The correlation coefficient between August NEAMS sea-level index (ANSI), which is the difference of atmospheric pressure anomalies between the KE and the WT, and the August NEAMS sea-level anomaly (ANSA) is 0.73. Although there is a significant correlation (coefficient: 0.64) between ANSA and the East Asian summer monsoon index (EASMI), ANSI might be more useful in estimating the variability of ANSA.

Esophageal perforation can lead to serious complications, and rapid diagnosis and treatment significantly affect the prognosis. Endoscopic vacuum-assisted closure (EndoVAC) therapy is widely accepted as a safe, well-tolerated, effective, versatile and practical procedure for the management of esophageal perforation in selected patients. We report the successful use of EndoVAC therapy for management of an esophageal perforation secondary to foreign body removal. A 56-year-old man presented to the emergency department for evaluation of chest pain after swallowing the plastic shell of a pill. Emergency endoscopy revealed an esophageal wall laceration (approximately 3 cm) and microperforation. The esophageal laceration and microperforation were limited to the mid-esophagus. The patient underwent EndoVAC therapy, which was repeated every 3–4 days for a total of six sessions over a period of 21 days. We observed improvement in the esophageal injury with granulation tissue formation during the fifth session. Subsequent follow-up evaluation, including esophagography and chest computed tomography confirmed complete healing of the esophageal injury. Following resumption of diet, the patienton a was discharged without any complications.

Abstract Colorectal cancer (CRC) is one of the top five most common and life-threatening malignancies worldwide. Most CRC develops from advanced colorectal adenoma (ACA), a precancerous stage, through the adenoma-carcinoma sequence. However, its underlying mechanisms, including how the tumor microenvironment changes, remain elusive. Therefore, we conducted an integrative analysis comparing RNA-seq data collected from 40 ACA patients who visited Dongguk University Ilsan Hospital with normal adjacent colons and tumor samples from 18 CRC patients collected from a public database. Differential expression analysis identified 21 and 79 sequentially up- or down-regulated genes across the continuum, respectively. The functional centrality of the continuum genes was assessed through network analysis, identifying 11 up- and 13 down-regulated hub-genes. Subsequently, we validated the prognostic effects of hub-genes using the Kaplan–Meier survival analysis. To estimate the immunological transition of the adenoma-carcinoma sequence, single-cell deconvolution and immune repertoire analyses were conducted. Significant composition changes for innate immunity cells and decreased plasma B-cells with immunoglobulin diversity were observed, along with distinctive immunoglobulin recombination patterns. Taken together, we believe our findings suggest underlying transcriptional and immunological changes during the adenoma-carcinoma sequence, contributing to the further development of pre-diagnostic markers for CRC.

Abstract Super Typhoon Mangkhut, which traversed the North Equatorial Current (NEC; 8–17 °N) in the western North Pacific in 2018, was the most intense Category-5 tropical cyclone (TC) with the longest duration in history—3.5 days. Here we show that the combination of two factors—high ocean heat content (OHC) and increased stratification — makes the NEC region the most favored area for a rapid intensification (RI) of super typhoons, instead of the Eddy Rich Zone (17–25 °N), which was considered the most relevant for RI occurrence. The high OHC results from a northward deepening thermocline in geostrophic balance with the westward-flowing NEC. The stratification is derived from precipitation associated with the Inter-Tropical Convergence Zone in the summer peak typhoon season. These factors, which are increasingly significant over the past four decades, impede the TC-induced sea surface cooling, thus enhancing RI of TCs and simultaneously maintaining super typhoons over the NEC region.

Background/Aims Guide tube-assisted endoscopy for procedures that require repeated endoscopic access is safer and more effective than conventional endoscopy. However, its effectiveness has not been confirmed in animal studies. We assessed the usefulness of guide tube-assisted endoscopic procedures in an in vivo porcine model. Methods Five different guide tube-assisted endoscopic procedures were performed by experienced endoscopists on a pig weighing 32 kg. To evaluate the efficacy of these procedures, we compared the endoscopic approach time when a guide tube was used to that when it was not. Additional endoscopic procedures using a guide tube were performed, including multiple foreign body extractions, multiple polypectomies, and multiple submucosal dissections. To evaluate safety, we compared the insertion force into the proximal esophagus between the guide tube and conventional overtube methods. Results Using the endoscopic approach with a guide tube required a shorter average approach time to reach the three target lesions than when using the endoscopic approach without a guide tube (p

Background/Aims We developed a new endoscopic submucosal dissection (ESD) simulator and evaluated its efficacy and realism for use training endoscopists. Methods An ESD simulator was constructed using polyvinyl alcohol hydrogel sheets and compared to a previous ESD simulator. Between March 1, 2020, and December 30, 2021, eight expert endoscopists from three different centers analyzed the procedure-related factors of the simulator. Five trainees performed gastric ESD exercises under the guidance of these experts. Results Although the two ESD simulators provided overall favorable outcomes in terms of ESD-related factors, the new simulator had several benefits, including better marking of the target lesion’s limits (p

The detection rate of gastrointestinal subepithelial lesions (SELs) has recently increased with the rise in screening endoscopies. Presumptive diagnoses can be made based on endoscopic features such as color, consistency, size, mobility, shape, and location, prior to definitive histologic diagnoses. For a more accurate differential diagnosis of SELs, endoscopic ultrasonography (EUS) may be necessary. EUS enables the identification of SEL characteristics like the layer of origin, exact size, depth of invasion, echogenicity, and borderline. It can also assess regional lymph node metastases. The behavior and treatment strategies for gastrointestinal SELs vary according to the characteristics of the tumor and the affected site. Neuroendocrine tumors (NETs), a type of SEL with malignant potential, can occur anywhere in the gastrointestinal tract, but are most commonly found in the rectum. Factors that increase the risk of local and distant metastases of rectal NETs include tumor size, involvement of the muscularis propria, differentiation index, and lymphovascular invasion. Therefore, EUS can assist in determining therapeutic strategies and predicting prognosis by measuring the size and depth of invasion of rectal NETs and regional lymph node metastases. However, its role in tissue acquisition is limited in the case of rectal NETs. This review focuses on the clinical applications of EUS imaging in diagnosing and treating rectal NETs.

Background/Aims Patients with inflammatory bowel disease (IBD) are diagnosed with ankylosing spondylitis (AS) often. However, the disease course of patients with both IBD and AS is not well understood. This study aims to evaluate the effect of concomitant AS on IBD outcomes. Methods Among the 4,722 patients with IBD who were treated in 3 academic hospitals from 2004 to 2021, 55 were also diagnosed with AS (IBD-AS group). Based on patients’ electronic medical records, the outcomes of IBD in IBD-AS group and IBD group without AS (IBD-only group) were appraised. Results The proportion of patients treated with biologics or small molecule therapies was significantly higher in IBD-AS group than the proportion in IBD-only group (27.3% vs. 12.7%, P=0.036). Patients with both ulcerative colitis and AS had a significantly higher risk of biologics or small molecule therapies than patients with only ulcerative colitis (P

Vitamin D may have anticancer effects against colorectal cancer (CRC). Bone mineral density (BMD) reflects the long-term vitamin D status. This study investigated the association between osteoporosis and colorectal neoplasms (CRN). The data were obtained from the National Health Insurance Service sample cohort, which included 60,386 osteoporosis patients and 8224 controls who underwent BMD in 2002–2019. The logistic regression models included age, sex, income level, and comorbidity. Sensitivity tests were performed using the data from the National Health Screening Program. In total, 7706 (11.2%) patients were diagnosed with CRN, and the proportion was significantly higher in osteoporosis patients than in controls (11.7% vs. 8.1%). In the multivariate analysis, osteoporosis was associated with an increased risk of CRN (odds ratio (OR) = 1.91, 95% confidence interval = 1.75–2.09, p < 0.0001), which was significant for both colorectal adenomas and CRC (OR = 1.88 and 1.83, respectively). A subgroup analysis by sex revealed a significant association between osteoporosis and CRN in both women and men (OR = 2.06 and 1.66, respectively). The sensitivity tests revealed results similar to those of the original dataset. In conclusion, osteoporosis is significantly associated with CRN risk in both sexes. In high-risk patients with low BMD, appropriate screening for CRN and vitamin D supplementation are required, regardless of sex.

The oral sulfate tablet (OST), commercially available as Orafang® (Pharmbio Korea Co., Seoul, Korea) in Korea, is being used increasingly because of its bowel-cleansing efficacy, safety, and tolerability in adults undergoing colonoscopy. Other bowel cleansing agents, such as polyethylene glycol and sodium picosulfate/magnesium citrate, can cause plasma volume depletion and electrolyte disturbances, such as hyponatremia. On the other hand, the OST has never been reported to cause hyponatremia in Korea. To our knowledge, the authors experienced the first case of hyponatremic seizure in an 81-year-old woman to whom an OST was administered for bowel preparation before a colonoscopy. After ingesting the OST, she presented with seizure, confusion, and dyspnea. Upon arrival, her serum sodium level was 120 mEq/L, and the urine osmolality and sodium levels were 449 mOsm/kg and 253 mOsm/kg, respectively; chest imaging suggested pulmonary edema. The associated symptoms disappeared following treatment with an intravenous injection of normal saline and 3% NaCl to normalize the sodium level. This case shows that the OST can cause hyponatremia and other severe complications related to hyponatremia.

Objectives: To investigate the clinical characteristics of adverse events (AEs) after COVID-19 vaccination in patients in South Korea. Design: Data from the Korean Disease Control and Prevention Agency on AEs from 4 COVID-19 vaccines, including AZD1222, BNT162b2, JNJ-78436735, and mRNA-1273, from February 26, 2021, to August 21, 2021, were assessed. The epidemiological characteristics, clinical symptoms, severity, complications, and mortality were descriptively analyzed. Results: Overall, 36.3 million individuals who completed the COVID-19 vaccination doses during the study period were included, and 153,183 AEs were reported. Most AEs occurred after the first dose (80.6%) and within a day (63.2%) after vaccination. Of the AEs, 95.5% were nonsevere cases; however, 4.5% were severe. Most mild AEs showed a similar frequency across all age groups, but major severe AEs and mortality events increased with age. Conclusions: Although there were differences in the frequency of occurrence, various adverse reactions were confirmed in using all 4 COVID-19 vaccines, even with the BNT162b2 (Pfizer-BioNTech) vaccine. Caution is needed, and further research should be continuously conducted.

Background/Aims: Previous studies have reported the protective effects of tauroursodeoxycholic acid (TUDCA) on gastric epithelial cells in some animal models, but the precise mechanisms are unclear. This study examined the effects of TUDCA on NF-κB signaling in gastric epithelial cells. Moreover, the protective effects of TUDCA in experimental gastritis models induced by ethanol and NSAID were evaluated and compared with ursodeoxycholic acid (UDCA). Methods: After a pretreatment with TUDCA or UDCA, human gastric epithelial MKN-45 cells were stimulated with tumor necrosis factor (TNF)-α to activate NF-κB signaling. A real-time PCR (RT-PCR) for human interleukin (IL)-1 mRNA was performed. An electrophoretic mobility shift assay (EMSA) and immunoblot analyses were carried out. In murine models, after a pretreatment with TUDCA or UDCA, ethanol and indomethacin were administered via oral gavage. Macroscopic and microscopic assessments were performed to evaluate the preventive effects of TUDCA and UDCA on murine gastritis. Results: A pretreatment with TUDCA downregulated the IL-1α mRNA levels in MKN-45 cells stimulated with TNF-α, as assessed by RT-PCR. As determined using EMSA, a pretreatment with TUDCA reduced the TNF-α-induced NF-κB DNA binding activity. A pretreatment with TUDCA inhibited IκBα phosphorylation induced by TNF-α, as assessed by immunoblot analysis. TUDCA attenuated the ethanol-induced and NSAID-induced gastritis in murine models, as determined macroscopically and microscopically. Conclusions: TUDCA inhibited NF-κB signaling in gastric epithelial cells and ameliorated ethanol- and NSAID-induced gastritis in murine models. These results support the potential of TUDCA for the prevention of gastritis in humans.

Background/Aims The efficacy of propofol in gastrointestinal endoscopy for patients with midazolam-induced paradoxical reactions remains unclarified. This study aimed to compare the efficacy and safety of propofol-based sedation in patients who previously experienced paradoxical reactions. Methods This was a prospective, single-blinded, randomized controlled pilot study. Participants with a history of paradoxical reactions to midazolam during a previous esophagogastroduodenoscopy were recruited and randomly assigned to group I (propofol monosedation) or group II (combination of propofol and midazolam). The primary endpoint was the occurrence of a paradoxical reaction. Results A total of 30 participants (mean age, 54.7±12.6 years; male, 19/30) were randomly assigned to group I (n=16) or group II (n=14). There were no paradoxical reactions in group I, but there were two in group II, without a significant difference (p=0.209). The mean dose of propofol was higher in group I than in group II (p=0.002). Meanwhile, the procedure and recovery times did not differ between groups. Conclusions Propofol-based sedation was safe and effective for patients who experienced paradoxical reactions to midazolam. However, caution is needed because few cases of paradoxical reaction again can happen in group II in which midazolam was readministered.

Background/Aims: The protective effects of vitamin D and calcium on colorectal neoplasms are known. Bone mineral density (BMD) may be a reliable biomarker that reflects the long-term anticancer effect of vitamin D and calcium. This study aimed to evaluate the association between BMD and colorectal adenomas including high-risk adenoma. Methods: A multicenter, cross-sectional, case-control study was conducted among participants with average risk of colorectal cancer who underwent BMD and screening colonoscopy between 2015 and 2019. The main outcome was the detection of colorectal neoplasms. The variable under consideration was low BMD (osteopenia/osteoporosis). The logistic regression model included baseline demographics, components of metabolic syndrome, fatty liver disease status, and aspirin and multivitamin use. Results: A total of 2,109 subjects were enrolled. The mean age was 52.1±10.8 years and 42.6% were male. The adenoma detection rate was 43%. Colorectal adenoma and high-risk adenoma were both more prevalent in subjects with low BMD than those with normal BMD (48.2% vs 38.8% and 12.1% vs 9.1%). In the univariate analysis, old age, male sex, smoking, metabolic components, fatty liver, and osteoporosis were significantly associated with the risk of adenoma and high-risk adenoma. In the multivariate analysis, osteoporosis was independently associated with risk of colorectal adenoma (odds ratio [OR], 1.65; 95% confidence interval [CI], 1.11 to 2.46; p=0.014) and high-risk adenoma (OR, 1.94; 95% CI, 1.14 to 3.29; p=0.014). Conclusions: Osteoporosis is an independent risk factor of colorectal adenoma and high-risk adenoma.

Background/Aims Combination of midazolam and opioids is used widely for endoscopic sedation. Compared with meperidine, fentanyl is reportedly associated with rapid recovery, turnover rate of endoscopy room, and quality of endoscopy. We compared fentanyl with meperidine when combined with midazolam for sedative colonoscopy. Methods A retrospective, cross-sectional, 1:2 matching study was conducted. Induction and recovery time were compared as the primary outcomes. Moreover, cecal intubation time, withdrawal time, total procedure time of colonoscopy, paradoxical reaction, adenoma detection rate, and adverse effect of midazolam or opioids were assessed as the secondary outcomes. Results A total of 129 subjects (43 fentanyl vs. 86 meperidine) were included in the analysis. The fentanyl group showed significantly more rapid induction time (4.5±2.7 min vs. 7.5±4.7 min, p

Background/Aims The quality of bowel preparation is one of the quality indicators for colonoscopy. The aim of this study was to compare the efficacy of oral sulfate solution (OSS) and polyethylene glycol plus ascorbic acid (PEG-AA) for bowel preparation. Methods The study involved 167 patients who underwent diagnostic colonoscopies. Inadequate bowel preparation was defined as any score of ≤1 in each colon section based on the Boston Bowel Preparation Scale. Multivariate logistic regression was used to compare the efficacy of OSS and PEG-AA. Subgroup analyses were performed based on patient characteristics. Results Overall, 106 (63.5%) patients received OSS, and 61 (36.5%) patients received PEG-AA. The rate of inadequate bowel preparation was 12.3% in patients receiving OSS and 32.8% in patients receiving PEG-AA (p=0.001). OSS (odds ratio [OR] = 0.26; p=0.003) and morning examination (OR=0.11; p=0.038) were significantly associated with efficient bowel preparation. The efficacy of OSS compared with PEG-AA was only significant in patients ≥50 years of age vs.

The prevalence of colorectal neoplasm in patients with non-alcoholic fatty liver disease has increased twice as high as that in the general population. FibroScan is a new modality for evaluating hepatic steatosis. This study aimed to investigate the relationship between the risk of high-risk colorectal neoplasia and hepatic steatosis examined using FibroScan. This was a cross sectional study of prospectively enrolled subjects who were scheduled to undergo index colonoscopy as a health screening between March 2018 and February 2019. The severity of steatosis was graded as normal, mild, moderate, or severe using FibroScan. A total of 140 consecutive subjects were enrolled and sequentially examined using FibroScan and colonoscopy. Subjects with hepatic steatosis had more high-risk colorectal neoplasia than those without hepatic steatosis. In addition, tumor size was larger in subjects with hepatic steatosis. In multivariable analysis, severe hepatic steatosis was an independent risk factor for high-risk colorectal neoplasia (adjusted odds ratio: 3.309, confidence interval: 1.043-10.498, p = 0.042). Alcohol consumption was also identified as a risk factor for high-risk colorectal neoplasia. In conclusion, severe hepatic steatosis on FibroScan is associated with the development of high-risk colorectal neoplasia. Thus, physicians should be aware of the association between colorectal neoplasia and hepatic steatosis assessed by FibroScan and its clinical implications.

Background/Aims Dietary fiber intake is considered a protective factor for diverticular disease such as diverticulitis. However, evidence for an inverse connection between dietary fiber consumption and asymptomatic colonic diverticulosis is lacking. Specifically, few studies have investigated this subject in Asians with different presentations of diverticulosis. Therefore, we assessed the protective effects of a vegetarian diet for asymptomatic colonic diverticulosis in Buddhist monks who are obligatory vegetarians for spiritual reasons compared with the general population. Methods A retrospective, cross-sectional, case-control study was conducted in age- and sex-matched Buddhist monks and the general population who underwent colonoscopy for screening at a Korean health promotion center from August 2005 to June 2018. We compared the prevalence of asymptomatic diverticulosis between the 2 groups using a self-administered questionnaire. Results In this study, a total of 1,316 individuals were included (Buddhist monks of 658 and general population of 658) with a mean age of 52.6±9.5 years. The prevalence of asymptomatic diverticulosis in Buddhist monks was lower compared with the general population (6.7% [44/658] vs. 10.8% [71/658], P=0.008). Buddhist monks had a higher rate of high body mass index (BMI) and metabolic syndrome. By a multivariate regression analysis model, a nonvegetarian diet (odds ratio [OR], 1.82; 95% confidence interval [CI], 1.21–2.72, P=0.004), old age (OR, 4.53; 95% CI, 1.36–15.12; P=0.014), male sex (OR, 1.91; 95% CI, 1.28–2.85; P=0.002), and a high BMI (OR, 1.50; 95% CI, 1.01–2.23; P=0.047) were independent predictors of asymptomatic diverticulosis. Moreover, a nonvegetarian diet was associated with both right-sided and left-sided diverticulosis. Conclusions A nonvegetarian diet may increase a risk of asymptomatic colonic diverticulosis in Asians.

Background/Aims: The Korean National Cancer Screening Program recommends biennial gastric cancer screening for patients aged ≥40 years. This study compared the characteristics of asymptomatic young gastric cancer patients aged

The incidence of colorectal cancer (CRC) is increasing among young adults in several countries including the United States. Early-onset colorectal cancer (EO-CRC) is heterogenous group and appears to have a distinct clinical, pathologic, and molecular presentation compared to CRC diagnosed in older patients. EO-CRC patients tend to be diagnosed at later stage and with symptomatic disease. Tumors arise predominantly in the distal colon and rectum and have poorer histological features. Microsatellite and chromosome stable molecular pathway is frequently observed in EO-CRC. Survival data of EO-CRC is conflicting and younger patients tend to be treated more aggressively. It is important to identify high risk and have them screened appropriately to address increasing EO-CRC. Screening and treatment strategies for EO-CRC should be developed through further investigation of molecular mechanism and various environmental risk factors. In Korea, EO-CRC and late-onset CRC have both declined in recent several years, probably due to many screening colonoscopies in young population. Close observation and analysis of EO-CRC in Korea is necessary.

AimLiver cirrhosis and features of muscle or adipose tissues may affect the severity of acute pancreatitis (AP). We aimed to evaluate the impact of body composition parameters and liver cirrhosis on the severity of AP in patients with alcohol-induced AP (AAP).MethodsPatients with presumed AAP who underwent CT within one week after admission were retrospectively enrolled. L3 sectional areas of abdominal fat and muscle, and mean muscle attenuations (MMAs) were quantified. The presence of liver cirrhosis was determined using clinical and CT findings. Factors potentially associated with moderately severe or severe AP were included in the multivariable logistic regression analysis.ResultsA total of 242 patients (47.0 ± 12.6 years, 215 males) with presumed AAP were included. The mild and moderately severe/severe (MSS) groups included 137 (56.6%) and 105 patients (43.4%), respectively. Patients in the MSS group had higher rates of liver cirrhosis, organ failure, and local complications. Among body composition parameters, mean MMA (33.4 vs 36.8 HU, PConclusionThe results of this study suggest that liver cirrhosis has a significant impact on the severity of AAP. Of the body composition parameters examined, MMA and abdominal muscle mass showed potential as promising predictors.

AimsMetabolic syndrome (MS) is a global health problem associated with an increased risk of diabetes mellitus (DM), cardiovascular disease (CVD), and cancer. Body composition parameters, including obesity, visceral adiposity, and sarcopenia contribute to the development of MS and CVD. Previous studies have investigated the association of individual body composition parameters with MS. Studies analyzing the association between multiple body composition parameters and MS have been rare. We aimed to investigate the association between MS and multiple body composition parameters, including obesity, visceral adiposity, and sarcopenia.MethodsA total of 13,620 subjects who underwent voluntary routine checkups at the Health Care Center of our institution between October 2014 and December 2019 were enrolled. Only data from the first examination of subjects who underwent repeated checkups were included. Clinical and laboratory data were collected. Skeletal muscle mass and visceral fat area (VFA) were measured using bioelectrical impedance analysis. Appendicular skeletal muscle mass (ASM) was divided by body weight (in kg) and expressed as a percentage (calculated as, ASM% = ASM × 100/Weight). Data were compared between the groups based on obesity, VFA, and ASM%. Logistic regression analysis was performed to determine the risk of MS in each group.ResultsBody mass index and VFA were significantly higher in subjects with MS than in those without MS. ASM% was significantly lower in subjects with MS than in those without MS. Subjects with obesity, visceral adiposity, or sarcopenia had a higher prevalence of MS than those without. As the number of metabolic components increased from 0 to 5, we identified a decreasing trend of ASM% and an increasing trend of VFA and BMI (P for trend < 0.001 for all). In the paired analyses, all the three body composition parameters showed additive effects in predicting MS. In the logistic regression analysis, the three parameters were associated with an increased risk of MS after adjustment for age, sex, hypertension, DM, dyslipidemia, smoking, alcohol intake, and C-reactive protein.ConclusionsObesity, visceral adiposity, and sarcopenia showed additive effects on MS prediction. Subjects with obesity, visceral adiposity, or sarcopenia were significantly associated with the increased risk of MS after adjustment for multiple confounders. Increasing skeletal muscle and reducing visceral fat may be strategies for the prevention or treatment of MS.

Background/Aim: Cecal intubation during colonoscopy is prone to be prolonged in women, which may be related to frequent exposure to pelvic/abdominal surgery. We evaluated the association between Cecal Intubation Time (CIT) and prior episodes of pelvic/abdominal surgery in women. Patients and Methods: A cross-sectional study was conducted on screening participants who underwent colonoscopy. Multivariate regression with parameter estimates (β) was performed to determine the factors affecting CIT, including age, body mass index (BMI), bowel preparation, sedation, diverticulosis, experience of colonoscopists, and a surgical history. Also, subgroup analyses according to type of surgery were performed. Results: A total of 835 women were enrolled. The mean CIT was 5.82 ± 3.40 min. 323 females (38.7%) had episodes of surgery. The CIT was prolonged in cases performed by non-experienced trainees (β = 3.61, P< 0.001) and with a history of gynecological surgery (β = 0.97, P = 0.001). In the subgroup of non-experienced trainees, lower BMI, poor preparation, and a history of cesarean section significantly prolonged the CIT. Also, the risk for difficult colonoscopy (CIT ≥ 15 min) was increased with a history of cesarean section (odds ratio = 4.43, P= 0.024). Conclusion: A prior episode of gynecological surgery prolonged CIT. Also, cesarean section history was associated with difficult colonoscopy in the examination by non-experienced trainees.

Background/Aims: Recent Korean studies performed over the past few decades have shown diminishing efficacy and unacceptability of clarithromycin-based triple therapy as first-line eradication therapy for Helicobacter pylori infection, based on evidence of a declining eradication rate. Triple therapy continues to be used as first-line eradication therapy despite concerns regarding high clarithromycin resistance among Koreans. Patient compliance and acid suppression are important factors associated with the H. pylori eradication rate. We investigated whether regular administration of a proton pump inhibitor (PPI) 30 minutes before a meal can improve the eradication rate. Materials and Methods: We retrospectively analyzed the data of 316 patients who were treated with first-line triple therapy (PPI, amoxicillin, and clarithromycin) for H. pylori infection between January 2012 and September 2017. Patients were divided into 2 groups based on the time of administration of the PPI (group A: before a meal, group B: after a meal). The urea breath test was performed 4∼6 weeks after eradication of infection. Results: Notably, 249 patients (78.8%, 249/316) showed successful eradication. The eradication rates in groups A and B were 87.5% (49/56 patients) and 76.9% (200/260 patients), respectively. We observed that regular administration of PPI before meals improved the eradication rate (P=0.079). Conclusions: We observed that although clarithromycin-based triple therapy was associated with an overall eradication rate ＜80%, regular PPI administration before meals improved the eradication rate. Regular PPI administration before meals and effective education to improve patient compliance could improve the eradication rate through maximal acid suppression.

Abstract Background Colorectal cancer (CRC) screening is the most efficient strategy to reduce disease-related mortality. Frequent aberrant DNA methylation is known to occur in selected genes and early during CRC development, which has emerged as a new epigenetic biomarker for early detection of CRC. Previously, we reported that we identified that CpG sites of SDC2 were aberrantly methylated in tumor tissues of most CRC patients through comprehensive methylation analysis and demonstrated a high potential of quantification of SDC2 methylation in blood for early detection of colorectal cancer. In this study, we aim to investigate the feasibility of quantifying SDC2 methylation in stool DNA for the early detection of CRC. The objective of this study was to confirm a high frequency of SDC2 methylation in tumor tissues at various stages of CRC and investigate the feasibility of a quantitative test for SDC2 methylation in fecal DNA by highly sensitive and accurate real-time PCR for early detection of CRC. Methods Bisulfite-pyrosequencing assay was performed to measure the SDC2 methylation status in tissue samples. For methylation analysis in stool DNA, a highly sensitive and accurate method was applied which implements consecutive two rounds of PCR consisting of unidirectional linear target enrichment (LTE) of SDC2 and quantitative methylation-specific real time PCR (qMSP) for SDC2, named as meSDC2 LTE-qMSP assay. Its limit of detection was 0.1% methylation (corresponding to ~ 6 copies in total ~ 6200 genome copies). Results Positive SDC2 methylation was observed in 100% of primary tumors, 90.6% of adenomatous polyps, 94.1% of hyperplastic polyps, and 0% of normal tissues. SDC2 methylation level also significantly (P

Mucosa-associated lymphoid tissue (MALT) lymphoma is found in various organs as extranodal B cell lymphoma. The gastrointestinal tract is the most commonly involved extranodal site in MALT lymphoma. However, primary esophageal MALT lymphoma is very rare. In addition, few cases with metachronous gastric involvement have been reported. A 55-year-old man was diagnosed with MALT lymphoma by surveillance esophagogastroduodenoscopy. A 5 cm esophageal submucosal tumor-like lesion was incidentally revealed by screening esophagogastroduodenoscopy two years prior. Esophagogastroduodenoscopy showed a cylindrically elongated submucosal mass with normal overlying mucosa in the mid esophagus. He underwent surgery to confirm the diagnosis. The pathologic diagnosis was esophageal MALT lymphoma. He was treated with radiation, which achieved complete remission. Esophagogastroduodenoscopy and chest computed tomography were performed every three to six months, with no evidence of recurrence for 18 months. After 21 months, several elevated gastric erosions were found on the great curvature and posterior sides of the midbody and confirmed as MALT lymphoma pathologically. Here we report a case with MALT lymphoma metachronously involving the esophagus and stomach. (Korean J Gastroenterol 2016;67:257-261)