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Background/Aims: Appropriate tissue tension and clear visibility of the dissection area using traction are essential for effective and safe endoscopic submucosal dissection (ESD). In this study, we developed a retractable robot-assisted traction device and evaluated its performance in colorectal ESD. Methods: An experienced endoscopist performed ESD 18 times on an ex vivo porcine colon using the robot and 18 times using the conventional method. The outcome measures were procedure time, dissection speed, procedure-related adverse events, and blind dissection rate. Results: Thirty-six colonic lesions were resected from ex vivo porcine colon samples. The total procedure time was significantly shorter in robot-assisted ESD (RESD) than in conventional ESD (CESD) (20.1±4.1 minutes vs 34.3±8.3 minutes, p<0.05). The submucosal dissection speed was significantly faster in the RESD group than in the CESD group (36.8±9.2 mm2 /min vs 18.1±4.7 mm2 /min, p<0.05). The blind dissection rate was also significantly lower in the RESD group (12.8%±3.4% vs 35.1%±3.9%, p<0.05). In an in vivo porcine feasibility study, the robotic device was attached to a colonoscope and successfully inserted into the proximal colon without damaging the colonic wall, and ESD was successfully performed. Conclusions: The dissection speed and safety profile improved significantly with the retractable RESD. Thus, our robotic device has the potential to provide simple, effective, and safe multidirectional traction during colonic ESD. [ABSTRACT FROM AUTHOR]

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

Background/Aims: Chitosan, a natural polymer widely used in the biomaterials field, has been proposed as a potential submucosal injection solution. The purpose of this study was to compare the performance and efficacy of aqueous chitosan solution and commercialized submucosal injection fluids using a three-dimensional sensor and to evaluate the efficacy of the measured parameters. Methods: Normal saline (0.9% NaCl), as a control, Eleview® (Poloxamer 188), Blue EyeTM (0.4% hyaluronic acid), and aqueous chitosan solution (2.0%) were injected into the submucosa of porcine stomachs ex vivo. The mucosal elevation height, elevated surface area, and angle of the tangent of the submucosal fluid cushion were measured using a three-dimensional sensor. The rates of change for each variable were calculated, and the correlation between parameters was analyzed. Tissue specimens were stained with hematoxylin and eosin. Results: All variables exhibited the highest values under chitosan injection. The mucosal elevation height rate of change differed significantly between normal saline and chitosan solution (p=0.024). The elevated surface area rates of change for normal saline and Eleview® were significantly different from those for TS-905 and chitosan solution (p=0.006 and p=0.009, respectively). Further, height, area, and angle showed a positive correlation (p<0.001). A histological examination revealed an even distribution of aqueous chitosan within the submucosa without tissue damage. Conclusions: Aqueous chitosan was superior to normal saline and Eleview® and was noninferior to TS-905. A three-dimensional sensor and the measured parameters were effective and useful for evaluating the performance of submucosal fluids. [ABSTRACT FROM AUTHOR]

Backgrounds/Aims: Rebleeding of gastric varices (GVs) after endoscopic variceal obturation (EVO) can be fatal. This study was performed to evaluate the usefulness of computed tomography (CT) for the prediction of rebleeding after EVO GV bleeding. Methods: Patients who were treated with EVO for GV bleeding and underwent CT before and after EVO were included. CT images of the portal phase showing pretreatment GVs and feeding vessels, and nonenhanced images showing posttreatment cyanoacrylate impaction were reviewed. Results: Fifty-three patients were included. Their mean age was 60.6±11.6 years, and 40 patients (75.5%) were men. Alcoholic liver disease was the most frequent underlying liver disease (45.3%). Complete impaction of cyanoacrylate in GVs and feeding vessels were achieved in 40 (75.5%) and 24 (45.3%) of patients, respectively. During the follow-up, GV rebleeding occurred in nine patients, and the cumulative incidences of GV rebleeding at 3, 6, and 12 months were 11.8%, 18.9%, and 18.9%, respectively. The GV rebleeding rate did not differ significantly according to the complete cyanoacrylate impaction in the GV, while it differed significantly according to complete cyanoacrylate impaction in the feeding vessels. The cumulative incidences of GV rebleeding at 3, 6, and 12 months were 22.3%, 35.2%, and 35.2%, respectively, in patients with incomplete impaction in feeding vessels, and there was no rebleeding during the follow-up period in patients with complete impaction in the feeding vessels (p=0.002). Conclusions: Abdominal CT is useful in the evaluation of the treatment response after EVO for GV bleeding. Incomplete cyanoacrylate impaction in feeding vessels is a risk factor for GV rebleeding. [ABSTRACT FROM AUTHOR]

Background/Aims: Recent studies have demonstrated that etomidate is a safe sedative drug with noninferior sedative effects. In our recent study, we revealed that etomidate/midazolam was more hemodynamically stable than propofol/ midazolam in elderly patients undergoing colonoscopies. We aimed to investigate whether compared with propofol/midazolam, etomidate/midazolam causes fewer cardiopulmonary adverse events with noninferior efficacy for screening colonoscopies in patients of all ages. Methods: In this singlecenter, randomized, double-blind study, we prospectively enrolled 200 patients. The patients were divided into etomidate and propofol groups. The primary outcome was the occurrence of cardiopulmonary adverse events. The secondary outcomes were the proportion of patients with fluctuations in vital signs (oxygen desaturation and transient hypotension), adverse events interrupting the procedure, and sedationrelated outcomes. Results: Adverse cardiopulmonary events were more common in the propofol group than the etomidate group (65.0% vs 51.0%, respectively; p=0.045). Fortysix patients (46.0%) in the propofol group and 29 (29.0%) in the etomidate group experienced fluctuations in their vital signs (p=0.013). The proportions of patients experiencing adverse events that interrupted the procedure, including myoclonus, were not significantly different between the two groups (etomidate: 20.0% vs propofol: 11.0%; p=0.079). Both groups had similar sedation-related outcomes. Multivariate analysis revealed that compared with the propofol groups, the etomidate group had a significantly lower risk of fluctuations in vital signs (odds ratio, 0.427; 95% confidence interval, 0.230 to 0.792; p=0.007). Conclusions: Compared with using propofol/midazolam, using etomidate/midazolam for screening colonoscopies results in more stable hemodynamic responses in patients of all ages; therefore, we recommend using etomidate/midazolam for colonoscopies in patients with cardiovascular risk factors. [ABSTRACT FROM AUTHOR]

Background/Aims: Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is useful for obtaining pancreatic mass samples. The combination of modified techniques (i.e., slow-pull technique and fanning technique) may improve the quality of the sample obtained by EUS-FNA. We investigated the effectiveness of a combined slow-pull fanning technique in EUS-FNA for pancreatic mass. Methods: This prospective comparative study investigated EUS-FNA performed for pancreatic solid masses between August 2015 and July 2016. Pairwise specimens were alternately obtained using the following two techniques for targeted pancreatic lesions: standard suction or slow-pull with fanning. We compared the specimen quality, blood contamination, and diagnostic accuracy of these techniques. Results: Forty-eight consecutive patients were included (29 men; mean age, 68.1±11.9 years), and 96 pancreatic mass specimens were obtained. The slow-pull with fanning technique had a significantly superior diagnostic accuracy than the suction technique (88% vs 71%, p=0.044). Furthermore, blood contamination was significantly reduced using the slow-pull with fanning technique (ratio of no or slight contamination, 77% vs 56%, p=0.041). No difference was observed in the acquisition of adequate cellularity between the groups. In the subgroup analysis, the tumor size and sampling technique were related to the EUSFNA diagnostic accuracy. Conclusions: The slow-pull with needle fanning technique showed a good diagnostic yield for EUS-FNA for pancreatic mass. This technique can be useful for performing EUS-guided sampling for diagnosing pancreatic disease. [ABSTRACT FROM AUTHOR]

Background/Aims: The adoption of colonoscopy as a primary colorectal cancer (CRC) screening technique has been argued for in Korea, without evidence of patient preferences. This study aimed to investigate patients' preferences for the primary CRC screening test for the National Cancer Screening Program (NCSP). Methods: Between June and August 2016, 414 individuals aged ≥50 years who participated in the NCSP were prospectively invited to complete a questionnaire regarding their preferences for the primary CRC screening test and the reasons for their selection. Results: Among the 396 respondents who completed the questionnaire, 124 individuals (31.3%) preferred the fecal immunochemical test (FIT), whereas 272 individuals (68.7%) preferred colonoscopy. Elderly participants preferred the FIT (p<0.001), whereas participants with a higher education level (p=0.030), a higher income level (p=0.009), or individuals with a family member (p=0.028) or acquaintance (p=0.013) with a history of CRC preferred colonoscopy. Only 12.9% of participants had a bad experience with a previous FIT; however, 39.3% of participants had a bad experience with a previous colonoscopy. Conclusions: Colonoscopy was preferred to FIT in a 2.2:1 ratio as the primary CRC screening test for the NCSP. Patients' preference for colonoscopy should be considered for the NCSP in Korea. [ABSTRACT FROM AUTHOR]

Background/Aims: We aimed to clarify the association of hepatitis B surface antigen (HBsAg)/hepatitis B core antigen (HBcAg) with the disease status and treatment response in patients with chronic hepatitis B (CHB). Methods: We investigated 171 biopsy-proven entecavir-treated CHB patients (109 hepatitis B e antigen [HBeAg]-positive, 62 HBeAg-negative). HBcAg expression was positive when ≥10% of hepatocytes stained, and classified into nuclear, mixed, and cytoplasmic patterns. HBsAg expressions were intracytoplasmic (diffuse, globular, and submembranous) and membranous. The histologic activity index (HAI) and fibrosis stage followed Ishak system. Results: In HBeAg-positive patients, older age, increased HAI score, advanced fibrosis, and reduced viral load were observed when HBcAg expression shifted from nucleus to cytoplasm in HBcAg-positive patients, and HBsAg expression from non-submembranous to submembranous in HBcAg-negative patients (all, p<0.05). In HBeAg-negative patients, only intracytoplasmic HBsAg expression patterns had clinical relevance with decreased ALT levels and viremia. In HBeAg-positive patients without favorable predictors of virologic response, negative HBcAg and membranous HBsAg expression predicted greater virologic response (both, p<0.05). The probability of HBeAg seroclearance was higher in patients with increased HAI or lacking HBcAg expression (both, p<0.05). Higher serum HBsAg levels and hepatocyte HBcAg positivity were associated with reduced serum HBsAg during first and post-first year treatment, respectively (both, p<0.05). Conclusions: Hepatocyte HBcAg/HBsAg expression is a good marker for disease status and predicting treatment response. [ABSTRACT FROM AUTHOR]

Background/Aims: We evaluated the characteristics of the National Cancer Screening Program (NCSP) and opinions regarding the National Endoscopy Quality Improvement Program (NEQIP). Methods: We surveyed physicians performing esophagogastroduodenoscopy and/or colonoscopy screenings as part of the NCSP via e-mail between July and August in 2015. The 32-item survey instrument included endoscopic capacity, sedation, and reprocessing of endoscopes as well as opinions regarding the NEQIP. Results: A total of 507 respondents were analyzed after the exclusion of 40 incomplete answers. Under the current capacity of the NCSP, the typical waiting time for screening endoscopy was less than 4 weeks in more than 90% of endoscopy units. Performance of endoscopy reprocessing was suboptimal, with 28% of respondents using unapproved disinfectants or not knowing the main ingredient of their disinfectants and 15% to 17% of respondents not following reprocessing protocols. Agreement with the NEQIP was optimal, because only 5.7% of respondents did not agree with NEQIP; however, familiarity with the NEQIP was suboptimal, because only 37.3% of respondents were familiar with the NEQIP criteria. Conclusions: The NEQIP remains suboptimal in Korea. Given the suboptimal performance of endoscopy reprocessing and low familiarity with the NEQIP, improved quality in endoscopy reprocessing and better understanding of the NEQIP should be emphasized in Korea. [ABSTRACT FROM AUTHOR]

Background/Aims: This study sought to characterize the current sedation practices of Korean endoscopists in real-world settings. Methods: All active members of the Korean Society of Gastrointestinal Endoscopy were invited to complete an anonymous 35-item questionnaire. Results: The overall response rate was 22.7% (1,332/5,860). Propofol-based sedation was the dominant method used in both elective esophagogastroduodenoscopy (55.6%) and colonoscopy (52.6%). The mean satisfaction score for propofol-based sedation was significantly higher than that for standard sedation in both examinations (all p<0.001). The use of propofol was supervised exclusively by endoscopists (98.6%). Endoscopists practicing in nonacademic settings, gastroenterologists, or endoscopists with Conclusions: Endoscopist-directed propofol administration is the predominant sedation method used in Korea. This survey strongly suggests that there is much room for quality improvement regarding sedation training and patient vigilance in endoscopist-directed sedation. [ABSTRACT FROM AUTHOR]

Background/Aims: Migraine is frequently accompanied by symptoms consistent with functional gastrointestinal disorders (FGIDs). This study evaluated the prevalence of functional gastrointestinal symptoms and assessed the symptoms' relationship with the concomitant functional symptoms of anxiety, depression, and headache-related disability. Methods: This prospective study included 109 patients with migraine who were recruited from a headache clinic at a teaching hospital. The participants completed a self-administered survey that collected information on headache characteristics, functional gastrointestinal symptoms (using Rome III criteria to classify FGID), anxiety, depression, and headache-related disability. Results: In total, 71% of patients met the Rome III criteria for at least one FGID. In patients with FGID, irritable bowel syndrome was the most common symptom (40.4%), followed by nausea and vomiting syndrome (24.8%) and functional dyspepsia (23.9%). Depression and anxiety scores were significantly higher in patients meeting the criteria for any FGID. The number of the symptoms consistent with FGID in individual patients correlated positively with depression and anxiety. Conclusions: FGID symptoms defined by the Rome III criteria are highly prevalent in migraine. These symptoms correlate with psychological comorbidities, such as depression and anxiety. [ABSTRACT FROM AUTHOR]

Background/Aims: Acute complicated diverticulitis can be subdivided into moderate diverticulitis and severe diverticulitis. Although there have been numerous studies on the risk factors for complicated diverticulitis, little research has focused on severe diverticulitis. This study was designed to identify the risk factors for severe diverticulitis in an acute diverticulitis attack using the modified Hinchey classification. Methods: Patients were included if they had any evidence of acute diverticulitis detected by computed tomography. The patients were subdivided into severe diverticulitis (Hinchey class ≥Ib; abscesses or peritonitis) and moderate diverticulitis (Hinchey class Ia; pericolic inflammation) groups. Results: Of the 128 patients, 25 exhibited severe diverticulitis, and 103 exhibited moderate diverticulitis. In a multivariate analysis, age >50 years (odds ratio [OR], 5.27; p=0.017), smoking (OR, 3.61; p=0.044), comorbidity (OR, 4.98; p=0.045), leukocytosis (OR, 7.70; p=0.003), recurrence (OR, 4.95; p=0.032), and left-sided diverticulitis (OR, 6.92; p=0.006) were significantly associated with severe diverticulitis. Conclusions: This study suggests that the risk factors for severe diverticulitis are age >50 years, smoking, comorbidity, leukocytosis, recurrent episodes, and left-sided diverticulitis. [ABSTRACT FROM AUTHOR]

Background/Aims The inflammatory bowel disease (IBD) is triggered by potent pro-inflammatory cytokine, the tumor necrosis factor-α (TNF-α). For the IBD treatment, various anti-TNF-α drugs have been developed, but monitoring of their effects in treatment was limited. Numerous target-specific antibody-fluorophore conjugates have been developed by linking antibodies to one-photon, near infrared, or natural fluorophores, but they also showed their limitations in its penetration depth and resolution. Therefore, we developed a two-photon (TP) probe for TNF-α by conjugating Pyr1 moiety with infliximab (Pyr1-infliximab) that can detect the TNF-α in a live cell and human colon tissue by TP microscopy. Methods We employed Pyr1 moiety as the fluorophore, propylene group as the spacer, and infliximab as the target. Pyr1-infliximab showed absorption maxima at 280 and 438 nm and emission maximum at 610 nm in aqueous buffer solution, and the effective TP action cross-section values of (520-2830) ' 10-50 cm4s/photon (GM) in RAW 264.7 cells, respectively. Results By labeling this probe, it was possible to detect the Pyr1-infliximab/trans-membrane TNF-α complexes in a live cell and the relative proportion of the PT complexes (PPT) in the human colon tissues. The PPT values in the healthy, inflammation suspected, and inflammation tissues of ulcerative colitis patients were 1.0/4.5/10. Conclusions Herein, we report that Pyr1-infliximab can detect TmTNF in a live cell and human colon tissue by TPM. This probe may find useful application for monitoring the response to biologic agents and further be a marker for an optimal treatment choice. [ABSTRACT FROM AUTHOR]

Background/Aims The gastrointestinal tract is covered by the serosa, a layer of epithelial cells. The serosa supports and binds each the gastrointestinal tract. However, the biomechanical roles of serosa on the active contraction of intestinal smooth muscles are not studied. In this study, biomechanical effects of the porcine intestinal serosa on the active contraction are investigated. Methods Five of experimental pigs (3 to 4 months) was sacrificed by the stomach surgery in a living state to obtain the specimens (width: 10 mm, length: 10 mm, and thickness: 3 mm) from small intestine. The isometric muscle contraction experiments were performed for the cases with (n=25) and without (n=25) the serosa (thickness of 0.2 to 0.5 mm) for five pigs using a muscle contraction inducer (acetylcholine: 1 mM) as described. The contractile forces of the specimens were measured in the transverse direction of the intestine. Results The muscle contractile force was decreased after reaching the maximum muscle contractile force. The maximum contractile force for without the serosa (11.72±1.38 mN) was higher than that for with the serosa (10.94±1.84 mN). The time intervals reaching the peak contractile force were similar for both with and without cases (p>0.05). The relaxation time intervals (from the peak contractile force to the initial force) were different between the with and without case (p<0.05). The relaxation time interval for the with case was shorter than that for the without case as much as 11%. Conclusions When the smooth muscle is relaxed, the serosa works as a compressed spring to apply a tensional force to the muscle. This would help to return quickly to the initial muscle length during relaxation. If this function of the serosa is changed by any other cause, abnormal contraction of the intestine could be occurred. [ABSTRACT FROM AUTHOR]

Background/Aims Thiopurine-related myelosuppression interferes with thiopurine therapy for patients with inflammatory bowel disease (IBD). We investigated whether pretreatment analyses genetic variants associated with thiopurine-induced leukopenia could be used to effectively identify patients who required dose adjustments. Methods We performed a multicenter, prospective study of patients with IBD at five tertiary medical centers in Korea, from January 2016 through September 2018. Seventy-two patients were randomly assigned to a group that underwent genotype analysis for the NUDT15 variant (rs116855232) and FTO variant (rs79206939) and three common TPMT variants (rs1800460, rs1800462, and rs1142345) associated with myelosuppression and 92 patients were assigned to a group that did not undergo genotype analysis (non-genotyping group). Patients heterozygous for any variant received 50 mg azathioprine equivalents, whereas those who were homozygous for any variant received alternative drugs. Patients who did not carry any of the genetic variants and patients in the non-genotyping group received 50 mg azathioprine equivalents followed by dose escalation up to 2-2.5 mg/kg. Results Twelve patients (16.7%) in the genotype analysis group and 33 patients (35.9%) in the non-genotyping group developed myelosuppression (p=0.005) (Fig.1). A multivariate analysis revealed that body mass indices above 21 kg/m2 (hazard ratio [HR], 0.43; 95% confidence interval [CI], 0.22 to 0.81; p=0.009), pretreatment genotype analysis (HR, 0.37; 95% CI, 0.18 to 0.77; p=0.008), and the maximum dose of thiopurines (HR, 0.34; 95% CI, 0.19 to 0.59; p<0.001) independently decreased risk of myelosuppression. Pretreatment genotype analysis reduced numbers of outpatient clinic visit and numbers of patients with drug discontinuation or dose reductions. Conclusions In a randomized controlled study of patients undergoing thiopurine therapy for IBD, selection of therapy based on genetic variants associated with thiopurine-induced leukopenia significantly reduced the proportion of patients with myelosuppression during treatment. [ABSTRACT FROM AUTHOR]

Background/Aims Recent studies have shown prevalence of irritable bowel syndrome was significantly higher in patients with allergic rhinitis. It has been suggested that allergic stimulants have a potential risk of aggravating colonic mucosal inflammation. The purpose of this study was to investigate whether induction of allergic rhinitis in the mouse model can lead to inflammation of colonic mucosa and irritable bowel syndrome. Methods Sixteen BALB/c mice were divided into two groups: six in normal and 10 in ovalbumin (OVA) treated group. OVA treated group was nebulized with OVA after intraperitoneal injection with OVA. A number of cytokines, interleukin (IL)-1b, IL-4, IL-5, IL-6, IL-10, IL-13, transforming growth factor α and interferon-γ (IFN-γ) in colonic membrane were measured by RT-PCR and multiplex protein analysis. Hematoxylin and eosin (H&E) staining was performed on colon tissues. Results Some of IL levels we measured were significantly higher in allergic group than in normal group. IL-1b, IL-4, IL-5, IL-6, IL-10 and IFN-γ in colonic mucosa were significantly higher in allergic group than in normal group (p<0.05). Based on H&E staining, inflammatory cell numbers were significantly greater in allergic group than in the control (p<0.05). The number of mast cells was also significantly greater (p<0.05). Conclusions Our data suggest that allergic stimulants increase cytokine expression and inflammatory production in an allergic murine model. This study showed allergic rhinitis in the mouse model can lead to inflammation of colonic mucosa and irritable bowel syndrome. [ABSTRACT FROM AUTHOR]

Background/Aims To assess the efficacy and safety of adalimumab, a recombinant human monoclonal antibody against tumor necrosis factor α (TNF-α), and to explore predictors of response in Korean patients with ulcerative colitis (UC). Methods We conducted a prospective observational multicenter study over 56 weeks in adult patients with moderately to severely active UC. The primary outcomes were rates of clinical response at week 8 and 56. Secondary outcomes were rates of clinical remission, steroid-free remission, and mucosal healing at week 8 and 56. Adalimumab drug levels were checked at week 8 and at loss of response. Results A total of 146 patients were enrolled and included in the analysis. Clinical response rates were 52.1% (76/146) and 37.7% (55/146) at week 8 and 56, respectively. Clinical remission were achieved in 24.0% (35/146) and 21.9% (32/146) of patients at week 8 and 56. Steroid-free remission rates was 21.2% (31/146) at week 56. Mucosal healing rates were 39.0% (57/146) and 30.1% (44/146) at week 8 and 56. Prior use of anti-TNF-α did not affect the primary and secondary outcomes. Adalimumab drug level was significantly higher in patients with clinical response, clinical remission, and mucosal healing at week 8. Clinical response (74.5% vs 38.5%, p<0.001) and mucosal healing (52.7% vs 30.8%, p=0.008) at week 8 were associated with clinical response at week 56. Serious adverse drug reactions were identified in 2.7% (4/146) of patients including one case of pulmonary tuberculosis. Conclusions Adalimumab is safe and effective for induction and maintenance in Korean patients with UC, regardless of prior anti-TNF therapy. A better response to induction therapy can predict a better long-term response. [ABSTRACT FROM AUTHOR]