Human Endometrium Derived Induced Pluripotent Stem Cells Are Amenable to Directed Erythroid Differentiation

BACKGROUND@#A protocol for using human endometrium derived induced pluripotent stem cells (iPSCs) to derive hematopoietic and erythroid lineages will be elaborated, through a two-phase culture system. @*METHODS@#Discarded endometrial tissues were obtained from women receiving hysterectomy in their 4th to 5th decade due to benign uterine conditions. pCE-Sox2, Oct4, Klf4, L-Myc and Lin28 episomal vectors were used to electrotransfect the endometrial stromal cells. The first 8 days involves commitment to hematopoietic stem cells through embryoid body with robust expansion on murine bone marrow stromal cells. The second phase involves feeder free conditions with hydrocortisone, stem cell factor, interleukin-3, and recombinant EPO. After 22 days of feeder free culture, the expression profiles of CD235a+ , CD34+ , CD43+ and CD 71+ were analyzed by flow cytometry and Wright-Giemsa staining for differential counting. The oxygen carrying capacity of cultured RBCs was measured using a hemoxanalyser. @*RESULTS@#As a result of inducing these cells via co-culture with murine stromal fibroblasts, all endometrium derived iPSCs were differentiated into erythroblasts with a stable yield of approximately 80% for polychromatic and orthochromatic normoblasts. The protocol for complete induction of erythroid lineage cells starting from human endometrial tissue via iPS cells has been optimized. @*CONCLUSION@#Successful directed erythroid differentiation has occurred from human endometrium-derived iPS cells. A comprehensive process of actually deriving iPS cells using discarded surgical hysterectomy specimens to the erythroid fate has significance in that the scope of using human iPSC cell lines for tissue regeneration could be expanded in the future.

Full mouth rehabilitation of a patient with excessive worn dentition by increasing vertical dimension of occlusion: a case report / 대한치과보철학회지

Tooth wear refers to the loss of dental hard tissue caused by various physiological and pathological causes, and excessive pathological wear can cause complications such as pathological changes in dimensions, occlusal disharmony, loss of function, and aesthetic problems. The cause of tooth wear can be caused by attrition, abrasion, corrosion and abfraction, and it is known to act in a multifactorial etiology in interocclusal activity. In patients with excessive pathological wear, it is important to determine whether or not the vertical dimension of occlusion is reduced, and complete oral rehabilitation should be achieved with the adaptation of the neuromuscular and temporomandibular joint through accurate diagnosis and analysis. The patient in this case was a 63-year-old male patient, who presented discomfort to cold beverage due to severe tooth wear. After analysis of the patient’s vertical dimension of occlusion, a full mouth rehabilitation was performed with increasing vertical dimension of occlusion. The goal of treatment was to improve the occlusal plane with the equal-intensity contact of all teeth, harmonious anterior guidance and immediate disclusion of all posterior contacts. After rehabilitation, the patient was satisfied with function and esthetic appearance.

Dental Age Estimation Using the Demirjian Method: Statistical Analysis Using Neural Networks / 대한법의학회지

In children and adolescents, dental age estimation is performed with the development of the teeth. Various statistical analysis methods have been used to determine the relationship between age and dental maturity and develop an accurate method of age calculation. This study attempted to apply a neural network model for the statistical analysis of dental age estimation in children and evaluated its applicability. This study used 1196 panoramic radiographs of patients aged 3–16 years, and 996 and 200 were randomly classified into training and test sets, respectively. The dental maturity of the mandibular left teeth was evaluated using Demirjian's method, the neural network model using the backpropagation algorithm was derived using training sets, and the errors were evaluated using 100 radiographs of each male and female as test sets. In addition, multiple linear regression analysis was conducted on the same training set, and the error was calculated by applying it to the test set and comparing it with the error of the neural network model. In the neural network model, the mean absolute error (MAE) and root mean squared error (RMSE) were 0.589 and 0.783 in male subjects and 0.529 and 0.760 in female subjects, respectively. In the multiple linear regression model, the MAE and RMSE were 0.600 and 0.748 in male subjects and 0.566 and 0.789 in female subjects, respectively. When applying the neural network model to the statistical analysis of the dental developmental stage, the results were as accurate as those of conventional statistical analysis methods. This study’s approach is expected to be useful for estimating the ages of children.

A Case of Anterior Communicating Artery Aneurysm Impending Rupture Presenting with Isolated Painful Adduction Palsy Mimicking Ischemic Internuclear Ophthalmoplegia

Anterior communicating artery (ACoA) aneurysms may rarely lead to oculomotor nerve palsy. We present here interesting cases in which isolated unilateral adduction paresis mimicking internuclear ophthalmoplegia (INO) was one of the symptoms of suspicious impending ruptured aneurysm of the ACoA. Careful neurologic examination is crucial for early discrimination with INO and oculomotor palsy.

Extremely Severe Dysphagia Secondary to Tracheostomy: A Case Report / 대한연하장애학회지

We report an extremely severe case of dysphagia in an elderly patient. Tracheostomy alone was found to be the cause of severe upper esophageal opening dysfunction. An 84-year-old woman was admitted with dyspnea. During hospitalization, she had respiratory failure and underwent a tracheostomy. On day 41 in the hospital, she complained of dysphagia and was a swallowing evaluation was done at the rehabilitation department. We ruled out other etiologies of upper esophageal dysfunction through a brain magnetic resonance imaging (MRI) and endoscopic evaluation. Through follow-up tests, it was found retrospectively that extreme dysphagia could have occurred through the following mechanism: the airway was not protected at the time of the tracheostomy because the movement of the epiglottis did not appear to be normal. This was due to the reduction in laryngeal function affecting the upper esophageal opening after the tracheostomy, and at the same time, the power to push the bolus was weak. After 6 months, at the third test, she had improved enough to ingest a soft diet and fluid with thickeners, so she was able to start an oral diet without decannulation. It is thus important to recognize that tracheostomy alone can cause extremely severe aspiration. If these findings are observed in patients undergoing tracheostomy, it is necessary to check the movements of the epiglottis properly and evaluate whether the condition can be improved by rehabilitation treatment.

Pediatric Nondysraphic Intramedullary Lipoma : Report of Two Cases and Review of the Literature

Pediatric nondysraphic intramedullary lipoma is very rare, and only limited cases have been reported. In the present case, we present two infant patients with these pathologies who were surgically treated. Previous literature on 20 patients with these diseases who had undergone surgical treatments was analyzed. Surgical treatment should be considered in most symptomatic patients, and laminoplastic laminotomy and internal debulking of the lipoma under intraoperative neurophysiological monitoring are mostly recommended.

Location of Ulnar Nerve Branches to the Flexor Carpi Ulnaris during Surgery for Cubital Tunnel Syndrome

Objective@#: Cubital tunnel syndrome, the most common ulnar nerve entrapment neuropathy, is usually managed by simple decompression or anterior transposition. One of the concerns in transposition is damage to the nerve branches around the elbow. In this study, the location of ulnar nerve branches to the flexor carpi ulnaris (FCU) was assessed during operations for cubital tunnel syndrome to provide information to reduce operation-related complications. @*Methods@#: A personal series (HJY) of cases operated for cubital tunnel syndrome was reviewed. Cases managed by transposition and location of branches to the FCU were selected for analysis. The function of the branches was confirmed by intraoperative nerve stimulation and the location of the branches was assessed by the distance from the center of medial epicondyle. @*Results@#: There was a total of 61 cases of cubital tunnel syndrome, among which 31 were treated by transposition. Twenty-one cases with information on the location of branches were analyzed. The average number of ulnar nerve branches around the elbow was 1.8 (0 to 3), only one case showed no branches. Most of the cases had one branch to the medial head, and one other to the lateral head of the FCU. There were two cases having branches without FCU responses (one branch in one case, three branches in another). The location of the branches to the medial head was 16.3±8.6 mm distal to the medial epicondyle (16 branches; range, 0 to 35 mm), to the lateral head was 19.5±9.5 mm distal to the medial epicondyle (19 branches; range, -5 to 30 mm). Branches without FCU responses were found from 20 mm proximal to the medial condyle to 15 mm distal to the medial epicondyle (five branches). Most of the branches to the medial head were 15 to 20 mm (50% of cases), and most to the lateral head were 15 to 25 mm (58% of cases). There were no cases of discernable weakness of the FCU after operation. @*Conclusion@#: In most cases of cubital tunnel syndrome, there are ulnar nerve branches around the elbow. Although there might be some cases with branches without FCU responses, most branches are to the FCU, and are to be saved. The operator should be watchful for branches about 15 to 25 mm distal to the medial epicondyle, where most branches come out.

Surgical Strategies for Partial Breast Reconstruction in Medial-Located Breast Cancer: A 12-Year Experience / 한국유방암학회지

Purpose@#Partial breast reconstruction is challenging in medially located breast cancer, particularly in terms of achieving satisfactory aesthetic coverage. Thus, we aimed to investigate surgical strategies for filling medial defects resulting from breast-conserving surgery to improve patient satisfaction and aesthetic outcomes. @*Methods@#We retrospectively evaluated 113 patients (114 cases) with medially located breast cancer between 2007 and 2018. We analysed the patient data, such as breast size, specimen weight, complications, and aesthetic results obtained using a questionnaire. @*Results@#The mean body mass index and specimen weight were 23.43 kg/m2 (range, 18.5–26.8) and 83.29 g (range, 15–290 g), respectively. The tennis racket and round-block techniques were chosen for small defects ( 30%). Hematoma was found in 1 case (0.96%), linear skin necrosis was found in 1 case (0.96%), seroma in the LD flaps was found in 8 cases (7.69%); fat necrosis in the rotational flaps was found in 2 cases (1.92%); and fat necrosis in an anterior intercostal artery perforator flap was found in 1 case (0.96%). 91 patients (87.5%) were satisfied with the aesthetic results. @*Conclusion@#The techniques used in this study for medially located breast cancer can produce fine aesthetic outcomes with regard to breast size and resection volume, with few complications.

Current Practice Patterns of Endoscopic Ultrasound-Guided Tissue Sampling for Pancreatic Solid Mass in Korea: Outcomes of a National Survey

Background/Aims@#Although endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) and fine needle biopsy (FNB) are widely used for tissue acquisition of pancreatic solid mass, the optimal strategy of this procedure has not been established yet. The aim of this nationwide study was to investigate the current practice patterns of EUS-FNA/FNB for pancreatic solid mass in Korea. @*Methods@#The Policy-Quality Management of the Korean Pancreatobiliary Association (KPBA) developed a questionnaire containing 22 questions. An electronic survey consisting of the questionnaire was distributed by e-mail to members registered to the KPBA. @*Results@#A total of 101 respondents completed the survey. Eighty respondents (79.2%) performed preoperative EUS-FNA/FNB for operable pancreatic solid mass. Acquire needles (60.4%) were used the most, followed by ProCore needles (47.5%). In terms of need size, most respondents (>80%) preferred 22-gauge needles regardless of the location of the mass. Negative suction with a 10-mL syringe (71.3%) as sampling technique was followed by stylet slow-pull (41.6%). More than three needle passes for EUS-FNA/FNB was performed by most respondents (>80%). The frequency of requiring repeated procedure was significantly higher in respondents with a low individual volume (<5 per month, p=0.001). Prophylactic antibiotics were routinely used in 39 respondents (38.6%); rapid on-site pathologic evaluation was used in 6.1%. @*Conclusions@#According to this survey, practices of EUS-FNA/FNB for pancreatic solid mass varied substantially, some of which differed considerably from the recommendations present in existing guidelines. These results suggest that the development of evidence-based quality guidelines fitting Korean clinical practice is needed to establish the optimal strategy for this procedure.

Impacts of Subtype on Clinical Feature and Outcome of Male Breast Cancer: Multicenter Study in Korea (KCSG BR16-09) / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#The treatment of male breast cancer (MBC) has been extrapolated from female breast cancer (FBC) because of its rarity despite their different clinicopathologic characteristics. We aimed to investigate the distribution of intrinsic subtypes based on immunohistochemistry, their clinical impact, and treatment pattern in clinical practice through a multicenter study in Korea. @*Materials and Methods@#We retrospectively analyzed clinical data of 248 MBC patients from 18 institutions across the country from January 1995 to July 2016. @*Results@#The median age of MBC patients was 63 years (range, 25 to 102 years). Among 148 intrinsic subtype classified patients, 61 (41.2%), 44 (29.7%), 29 (19.5%), and 14 (9.5%) were luminal A, luminal B, human epidermal growth factor receptor 2, and triple-negative breast cancer, respectively. Luminal A subtype showed trends for superior survival compared to other subtypes. Most hormone receptor-positive patients (166 patients, 82.6%) received adjuvant endocrine treatment. Five-year completion of adjuvant endocrine treatment was associated with superior disease-free survival (DFS) in patients classified with an intrinsic subtype (hazard ratio [HR], 0.15; 95% confidence interval [CI], 0.04 to 0.49; p=0.002) and in all patients (HR, 0.16; 95% CI, 0.05 to 0.54; p=0.003). @*Conclusion@#Distribution of subtypes of MBC was similar to FBC and luminal type A was most common. Overall survival tended to be improved for luminal A subtype, although there was no statistical significance. Completion of adjuvant endocrine treatment was associated with prolonged DFS in intrinsic subtype classified patients. MBC patients tended to receive less treatment. MBC patients should receive standard treatment according to guidelines as FBC patients.

Acute Cholangitis with Common Bile Duct Stone Caused by Lactococcus garvieae: A Case Report / 대한췌담도학회지

Lactococcus garvieae is a Gram-positive cocci that has been known to be a fish pathogen, and considered as a low virulence organism rarely associated with human infection. We report a case of acute cholangitis with common bile duct (CBD) stone and bacteremia by L. garvieae bacteremia in a 70-year-old male. The patient presented with epigastric pain and was diagnosed with two CBD stones. Blood culture obtained prior to empiric antimicrobial therapy with ceftizoxime sodium showed growth with Escherichia coli and L. garvieae. The bacteria were confirmed by matrix-assisted desorption/ionization time-of-flight mass spectrometry. Initial attempt at endoscopic biliary drainage failed, and the patient underwent percutaneous transhepatic biliary drainage and subsequent stone removal. He occasionally ingested raw fish and had a history of gastric ulcer with acid suppression therapy, which could be possible risk factors for L. garvieae infection. This is the first case of L. garvieae bacteremia in acute cholangitis.

Improved Intermediate Visual Function with New Monofocal Intraocular Lens in Combined Cataract and Vitrectomy Surgery for Retinal Disease

Purpose@#To evaluate the usefulness of a newly generated monofocal intraocular lens (IOL) in patients with various retinal diseases who underwent combined cataract and pars plana vitrectomy surgery. @*Methods@#This prospective observational study included 33 patients with various retinal diseases. Monocular best-corrected distance visual acuity (BCDVA), uncorrected distance visual acuity (UCDVA), uncorrected intermediate visual acuity (UCIVA), uncorrected near visual acuity (UCNVA), and contrast sensitivity were measured and compared with 40 age-matched patients in the standard monofocal IOL. @*Results@#The Eyhance IOL group demonstrated significantly better UCIVA at 6 months follow-up compared to the standard monofocal IOL group. No significant differences were observed between the two groups in contrast sensitivity, BCDVA, UCDVA, or UCNVA. The regression analysis showed a significant association between preoperative corrected distance visual acuity and improved UCIVA in the Eyhance IOL group. @*Conclusions@#The Eyhance ICB00 IOL proved to be a valuable option for patients with retinal diseases undergoing combined cataract surgery and vitrectomy. It effectively improved intermediate vision without compromising contrast sensitivity or distance visual acuity.

A novel technique of handling the blade for videolaryngoscopy intubation in patients with a semi-rigid neck collar: a prospective randomized controlled trial / 대한마취과학회지

Background@#Semi-rigid neck collars to protect the cervical spine can limit the extent of neck movement and mouth opening; this may further complicate orotracheal intubation. We aimed to compare intubation environments obtained with videolaryngoscopy using the technique of gliding a blade under the epiglottis and that obtained using the conventional Macintosh blade technique of blade tip placement on the vallecula. @*Methods@#This prospective randomized study included patients aged ≥ 20 years with American Society of Anesthesiologists physical status I–III scheduled for cervical spine surgery between October 2020 and August 2021. Patients were divided into two groups according to the placement of the blade of the McGrathTM videolaryngoscope: the gliding and conventional groups. The percentage of glottic opening (POGO) score was the primary endpoint. We also recorded the time to obtain the optimal laryngoscopic view, intubation duration, and ease and satisfaction of the researcher performing intubation. @*Results@#Among 176 patients, the POGO scores were significantly higher in the gliding group than in the conventional group (88.9 ± 14.7 vs. 63.8 ± 27.4, P < 0.001). The time to achieve the optimal glottic view for intubation and duration of intubation were also shorter, and ease and satisfaction in performing intubation were better in the gliding group than in the conventional group. @*Conclusion@#Our findings demonstrated a superior glottic view and more favorable intubation environments when the blade tip was placed under the epiglottis than using the conventional Macintosh technique in patients with immobilized cervical spine.

Clinical and Genetic Features of Korean Inherited Arrhythmia Probands

Background and Objectives@#Inherited arrhythmia (IA) is a more common cause of sudden cardiac death in Asian population, but little is known about the genetic background of Asian IA probands. We aimed to investigate the clinical characteristics and analyze the genetic underpinnings of IA in a Korean cohort. @*Methods@#This study was conducted in a multicenter cohort of the Korean IA Registry from 2014 to 2017. Genetic testing was performed using a next-generation sequencing panel including 174 causative genes of cardiovascular disease. @*Results@#Among the 265 IA probands, idiopathic ventricular fibrillation (IVF) and Brugada Syndrome (BrS) was the most prevalent diseases (96 and 95 cases respectively), followed by long QT syndrome (LQTS, n=54). Two-hundred-sixteen probands underwent genetic testing, and 69 probands (31.9%) were detected with genetic variant, with yield of pathogenic or likely pathogenic variant as 6.4%. Left ventricular ejection fraction was significantly lower in genotype positive probands (54.7±11.3 vs. 59.3±9.2%, p=0.005). IVF probands showed highest yield of positive genotype (54.0%), followed by LQTS (23.8%), and BrS (19.5%). @*Conclusions@#There were significant differences in clinical characteristics and genetic yields among BrS, LQTS, and IVF. Genetic testing did not provide better yield for BrS and LQTS. On the other hand, in IVF, genetic testing using multiple gene panel might enable the molecular diagnosis of concealed genotype, which may alter future clinical diagnosis and management strategies.

Lexical-semantic Deficit without Semantic Impairment in a Patient with Left Anterior Choroidal Artery Infarction: Neural Correlates Based on Diffusion-tensor Tractography

A 35-year-old male presented with atypical aphasia following left anterior choroidal artery infarction associated with distal internal carotid artery dissection. He presented with 1) lexical-semantic deficit without semantic impairment, 2) frequent surface errors (both surface dyslexia and dysgraphia), and 3) intact non-word reading/repetition (preserved sub-lexical route), suggesting deficit in the phonological output lexicon. Diffusion-tensor tractography analysis revealed disruption in the inferior fronto-occipital fasciculus and inferior longitudinal fasciculus, which might serve as potential subcortical neural correlates for phonological output lexicon.

Impact of Nonpharmacological Interventions on Severe Acute Respiratory Infections in Children: From

Background@#Nonpharmacological interventions (NPIs) reduce the incidence of respiratory infections. After NPIs imposed during the coronavirus disease 2019 pandemic ceased, respiratory infections gradually increased worldwide. However, few studies have been conducted on severe respiratory infections requiring hospitalization in pediatric patients.This study compares epidemiological changes in severe respiratory infections during pre-NPI, NPI, and post-NPI periods in order to evaluate the effect of that NPI on severe respiratory infections in children. @*Methods@#We retrospectively studied data collected at 13 Korean sentinel sites from January 2018 to October 2022 that were lodged in the national Severe Acute Respiratory Infections (SARIs) surveillance database. @*Results@#A total of 9,631 pediatric patients were admitted with SARIs during the pre-NPI period, 579 during the NPI period, and 1,580 during the post-NPI period. During the NPI period, the number of pediatric patients hospitalized with severe respiratory infections decreased dramatically, thus from 72.1 per 1,000 to 6.6 per 1,000. However, after NPIs ceased, the number increased to 22.8 per 1,000. During the post-NPI period, the positive test rate increased to the level noted before the pandemic. @*Conclusion@#Strict NPIs including school and daycare center closures effectively reduced severe respiratory infections requiring hospitalization of children. However, childcare was severely compromised. To prepare for future respiratory infections, there is a need to develop a social consensus on NPIs that are appropriate for children.

Risk Factors for the Occurrence and Severity of Vertebral Fractures in Inflammatory Bowel Disease Patients: A Nationwide Population-Based Cohort Study

Background@#The risk of vertebral fractures is increased in inflammatory bowel disease (IBD) patients. However, whether the severity of vertebral fractures differs between IBD patients and the general population, or between patients with Crohn’s disease (CD) and ulcerative colitis (UC), is unknown. @*Methods@#We investigated risk factors associated with the occurrence and severity of vertebral fractures in IBD patients using The National Healthcare Insurance Service (NHIS) database. We defined the patients who underwent vertebroplasty or kyphoplasty after being diagnosed with a vertebral fracture as having a severe vertebral fracture than those with only diagnosis codes. @*Results@#From 2008 to 2018, there were 33,778 patients with IBD (24,370 UC patients and 9,408 CD patients) and 101,265 patients in the reference population. The incidence rate ratio of vertebral fractures in the IBD patients was 1.27 per 1,000 person-years (95% confidence interval [CI], 1.26–1.27). The risk of vertebral fracture was higher in CD and UC patients than in the matched reference group (hazard ratio [HR], 1.59; 95% CI, 1.31–1.92; P < 0.001 and UC: HR, 1.46; 95% CI, 1.29–1.65, P < 0.001), and long-term steroid use (CD:HR, 3.71; 95% CI, 2.84–3.37; P < 0.001 and UC: HR, 3.88; 95% CI, 3.07–4.91; P < 0.001). The severity of vertebral fractures was associated with IBD (CD: HR, 1.82; 95% CI, 1.17–2.83; P = 0.008 and UC: HR, 1.49; 95% CI, 1.17–1.89; P < 0.001) and older age (HR, 1.06; 95% CI, 1.05–1.07; P < 0.001). @*Conclusion@#Vertebral fractures occur frequently and more severely in IBD patients, particularly those with CD. Therefore, we suggest monitoring of bone density, regular vitamin D supply, and reducing the use of corticosteroids to prevent vertebral fractures in IBD patients who are older, female, or have comorbidities.

National Survey Regarding the Management of Difficult Bile Duct Stones in South Korea

Background/Aims@#This study aimed to investigate the patterns of preferred endoscopic procedure types and techniques for managing difficult common bile duct (CBD) stones in South Korea. @*Methods@#The Committee of Policy and Quality Management of Korean Pancreatobiliary Association (KPBA) conducted a survey containing 19 questions. Both paper and online surveys were carried out; with the paper survey being conducted during the 2019 Annual Congress of KPBA and the online survey being conducted through Google Forms from April 2020 to February 2021. @*Results@#The response rate was approximately 41.3% (86/208). Sixty-two (73.0%) worked at tertiary hospitals or academic medical centers, and 60 (69.7%) had more than 5 years of endoscopic retrograde cholangiopancreatography experience. The preferred size criteria for large CBD stones were 15 mm (40.6%), 20 mm (31.3%), and 30 mm (4.6%). For managing of large CBD stones, endoscopic papillary large balloon dilation after endoscopic sphincterotomy was the most preferred technique (74.4%). When performing procedures in those with bleeding diathesis, 64 (74.4%) respondents favored endoscopic papillary balloon dilation (EPBD) alone or EPBD with small endoscopic sphincterotomy. Fifty-five respondents (63.9%) preferred the doubleguidewire technique when faced with difficult bile duct cannulation in patients with periampullary diverticulum. In surgically altered anatomies, cap-fitted forward viewing endoscopy (76.7%) and percutaneous transhepatic cholangioscopy (48.8%) were the preferred techniques for Billroth-II anastomosis and total gastrectomy with Roux-en-Y anastomosis, respectively. @*Conclusions@#Most respondents showed unifying trends for the management of difficult CBD stones. The current practice patterns could be used as basic data for clinical quality improvements in the management of difficult CBD stones.

Oral Sulfate Solution Is as Effective as Polyethylene Glycol with Ascorbic Acid in a Split Method for Bowel Preparation in Patients with Inactive Ulcerative Colitis: A Randomized, Multicenter, and Single-Blind Clinical Trial

Background/Aims@#Low-volume preparations for colonoscopy are gaining attention for their higher acceptability. However, the efficacy and safety of oral sulfate solution (OSS) preparations in patients with ulcerative colitis (UC) has not been well known. Therefore, we aimed to compare OSS and 2-L polyethylene glycol with ascorbic acid (PEG+Asc) for bowel preparation in inactive UC. @*Methods@#A multicenter, randomized, single-blind study was conducted at six tertiary referral hospitals in Korea. Outpatients with UC who had stable disease activity were randomly allocated to the OSS group or the 2-L PEG+Asc group for bowel preparation before colonoscopy. The study outcomes included treatment efficacy, safety, tolerability, and acceptability. Bowel cleansing was assessed using the Boston Bowel Preparation Scale and rated as successful cleansing if the score was ≥6. Patient acceptance and tolerability were assessed using a 4-point ordinal scale. Additionally, disease activity and laboratory data before and after colonoscopy were evaluated to check for safety. @*Results@#The OSS and 2-L PEG+Asc groups included 92 and 93 participants, respectively. No significant between-group difference was noted in successful cleansing (OSS [96.7%] vs 2-L PEG+Asc [97.8%], p=0.64). Moreover, the safety, acceptance, and tolerability were not significantly different (all p>0.05). Furthermore, no significant changes were found in serum electrolytes or disease activity in either group. @*Conclusions@#OSS is effective for colonoscopy cleansing, has acceptable tolerability, and does not affect disease activity; thus, it can be used safely for bowel preparation in patients with inactive UC.

Usefulness of a new polyvinyl alcohol hydrogel (PVA-H)-based simulator for endoscopic submucosal dissection training: a pilot study

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<0.001) and overall handling (p<0.001). Trainees tested the usefulness of the new ESD simulator. The complete resection rate improved after 3 ESD training sessions (9 procedures), and the perforation rate decreased after 4 sessions (12 procedures). @*Conclusions@#We have developed a new ESD simulator that can help beginners achieve a high level of technical experience before performing real-time ESD procedures in patients.