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Excitons in semiconductors and molecules are widely utilized in photovoltaics and optoelectronics, and high-temperature coherent quantum states of excitons can be realized in artificial electron-hole bilayers and an exotic material of an excitonic insulator (EI). Here, we investigate the band gap evolution of a putative high-temperature EI Ta 2 NiSe 5 upon surface doing by alkali adsorbates with angle-resolved photoemission and density functional theory (DFT) calculations. The conduction band of Ta 2 NiSe 5 is filled by the charge transfer from alkali adsorbates, and the band gap decreases drastically upon the increase of metallic electron density. Our DFT calculation, however, reveals that there exist both structural and excitonic contributions to the band gap tuned. While electron doping reduces the band gap substantially, it alone is not enough to close the band gap. In contrast, the structural distortion induced by the alkali adsorbate plays a critical role in the gap closure. This work indicates a combined electronic and structural nature for the EI phase of the present system and the complexity of surface doping beyond charge transfer.

Symmetry-protected band degeneracy, coupled with a magnetic order, is the key to realizing novel magnetoelectric phenomena in topological magnets. While the spin-polarized nodal states have been identified to introduce extremely-sensitive electronic responses to the magnetic states, their possible role in determining magnetic ground states has remained elusive. Here, taking external pressure as a control knob, we show that a metal-insulator transition, a spin-reorientation transition, and a structural modification occur concomitantly when the nodal-line state crosses the Fermi level in a ferrimagnetic semiconductor Mn 3 Si 2 Te 6 . These unique pressure-driven magnetic and electronic transitions, associated with the dome-shaped T c variation up to nearly room temperature, originate from the interplay between the spin-orbit coupling of the nodal-line state and magnetic frustration of localized spins. Our findings highlight that the nodal-line states, isolated from other trivial states, can facilitate strongly tunable magnetic properties in topological magnets., (© 2024. The Author(s).)

Endoscopic biliary stent insertion has been widely used for the treatment of benign biliary stricture (BBS). Thus, the development of stent materials in the perspectives of structure, mechanical properties, and biocompatibility has been also studied. However, conventional metal and plastic stents have several disadvantages, such as repeated procedures to remove or exchange them, dislodgment, restenosis, biocompatibility, and poor mechanical properties. Sustainable effectiveness, attenuation and prevention of fibrosis, and biocompatibility are key factors for the clinical application of stents to BBS treatment. In addition, loading drugs could show synergistic effects with stents' own performance. We developed a dexamethasone-eluting biodegradable stent (DBS) consisting of a sheath/core structure with outstanding mechanical properties and sustained release of dexamethasone, which maintained its functions in a BBS duct over 12 weeks in a swine model. The insertion of our DBS not only expanded BBS areas but also healed secondary ulcers as a result of the attenuation of fibrosis. After 16 weeks from the insertion, BBS areas were totally improved, and the DBS was degraded and thoroughly disappeared without re-intervention for stent removal. Our DBS would be an effective clinical tool for non-vascular diseases. STATEMENT OF SIGNIFICANCE: This study describes the insertion of a drug-eluting biodegradable stent (DBS) into the bile duct. The sheath/core structure of DBS confers substantial durability and a sustained drug release profile. Drug released from the DBS exhibited anti-fibrotic effects without inflammatory responses in both in vitro and in vivo experiments. The DBS maintained its function over 12 weeks after insertion into the common bile duct, expanding benign biliary stricture (BBS) and reducing inflammation to heal secondary ulcers in a swine BBS model. After 16 weeks from the DBS insertion, the DBS thoroughly disappeared without re-intervention for stent removal, resulting in totally improved BBS areas. Our findings not only spotlight the understanding of the sheath/core structure of the biodegradable stent, but also pave the way for the further application for non-vascular diseases., Competing Interests: Declaration of competing interest No other authors have potential conflicts of interest to declare., (Copyright © 2024 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Although functional dyspepsia (FD) is a common functional gastroduodenal disorder with a high socioeconomic burden, little is known about its global prevalence. Thus, we performed a comprehensive study to estimate long-term trends in the prevalence of FD. We searched PubMed/MEDLINE, Embase, and Google Scholar from 1990 to 2022 for population-based studies that reported the prevalence of FD in adults (≥ 18 years old) according to Rome I, II, III, or IV criteria. The prevalence of FD was extracted from included studies to obtain pooled prevalence with 95% confidence intervals (CI) and 95% prediction intervals. Subgroup analysis was performed according to certain characteristics, including geographic region. A total of 44 studies met the eligibility criteria, including 256,915 participants from 40 countries across six continents. The overall global pooled prevalence of FD was 8.4% (95% CI 7.4-.9.5). The prevalence was the highest in Rome I (11.9%; 95% CI 5.1-25.4) and lowest in Rome IV (6.8%; 95% CI 5.8-7.9). Developing countries showed a higher prevalence than developed countries (9.1% versus 8.0%), and prevalence was higher in women, irrespective of the definition used (9.0% versus 7.0%). The pooled prevalence gradually decreased from 1990 to 2020 (12.4% [8.2-18.3] in 1990-2002 versus 7.3% [6.1-8.7] in 2013-2020). The prevalence of FD differs by country, economic status, geographical region, and sex, and the global prevalence has been gradually declining. Despite the heterogeneity of sample population, our study estimates the current global burden of FD and provides information to heath care policy decisions., (© 2024. The Author(s).)

Competing Interests: The authors declare that they have no conflict of interest.

Background/aims: Minimal pelvic fluid (MPF) is occasionally encountered on computed tomography (CT) scans during the initial staging of newly diagnosed pancreatic cancer. However, its clinical relevance has scarcely been studied. This study intends to explore the incidence of minimal pelvic fluid and its relevance in terms of survival in locally advanced pancreatic cancer (LAPC) patients., Materials and Methods: The medical records of patients with LAPC at 4 tertiary referral institutions were retrospectively reviewed from January 2005 to December 2015. Minimal pelvic fluid was defined as a fluid collection volume in the pelvic cavity of <100 mL as determined by abdominal CT. The association between the presence of MPF and patient survival was evaluated., Results: A total of 59 patients (male:female, 33:26; median age, 68 years; range 46-82 years) with LAPC were enrolled. Of the 59 patients, 22.0% (n = 13) had MPF, and 78.0% (n = 46) had no pelvic fluid (NPF). Baseline clinical characteristics in the 2 groups, including extent of the tumor stage, extent of spread to the lymph nodes stage, and pattern of treatments, were not significantly different. However, median overall survival was significantly less in the MPF group [9.7 months, (95% CI, 5.9-13.5)] than in the NPF group as determined by the log-rank test [16.9 months, (95% CI, 9.3-24.5)] (P = .002), and univariate and multivariate analyses showed that the presence of MPF independently predicted a poor prognosis., Conclusion: The presence of MPF was found to be significantly associated with reduced survival and an independent poor prognostic biomarker in LAPC patients.

Background/aims: The use of a self-expandable metal stent (SEMS) is recommended for unresectable malignant biliary obstruction (MBO). Stent-related adverse events might differ according to the position of the stent through the ampulla of Vater (AOV). We retrospectively evaluated SEMS patency and adverse events according to the position of the SEMS., Methods: In total, 280 patients who underwent endoscopic SEMS placement due to malignant distal biliary obstruction were analyzed retrospectively. Suprapapillary and transpapillary SEMS insertions were performed on 51 patients and 229 patients, respectively., Results: Between the suprapapillary group (SPG) and transpapillary group (TPG), the stent patency period was not significantly different (median [95% confidence interval]: 107 days [82.3 to 131.7] vs 120 days [99.3 to 140.7], p=0.559). There was also no significant difference in the rate of adverse events. In subgroup analysis, the stent patency for an MBO located within 2 cm from the AOV was found to be significantly shorter than that for an MBO located more than 2 cm from the AOV in the SPG (64 days [0 to 160.4] vs 127 days [82.0 to 171.9], p<0.001) and TPG (87 days [52.5 to 121.5] vs 130 [97.0 to 162.9], p<0.001). Patients with an MBO located within 2 cm from the AOV in both groups had a higher percentage of duodenal invasion (SPG: 40.0% vs 4.9%, p=0.002; TPG: 28.6% vs 2.9%, p<0.001) than patients with an MBO located more than 2 cm from the AOV., Conclusions: The SPG and TPG showed similar results in terms of stent patency and rate of adverse events. However, patients with an MBO located within 2 cm from the AOV had a higher percentage of duodenal invasion with shorter stent patency than those with an MBO located more than 2 cm from the AOV, regardless of stent position.

Background and Aims: Various guidewires are used for biliary cannulation, and each one has its own characteristics affecting its effectiveness. This study aimed to measure the basic properties and evaluate the effectiveness of a newly developed 0.025-inch guidewire for selective biliary cannulation., Methods: A total of 190 patients at five referral hospitals were randomly allocated to undergo selective biliary cannulation using the newly developed guidewire (NGW group, n = 95) or a conventional guidewire (CGW group, n = 95). The primary outcome was the selective biliary cannulation rate in naïve papillae. The secondary outcome was to measure the NGW basic properties, compare them with those of the CGW, and analyze the importance of basic property differences., Results: There were no significant differences between the groups in the baseline characteristics. The primary outcome (75.8% vs. 84.2%, p = 0.102) and adverse event rate (6.3% vs. 4.2%, p = 0.374) were similar in both groups. However, compared with the CGW group, the NGW group showed a higher number of ampulla contacts (2.58 vs. 2.02, p = 0.011) and longer cannulation time (216.5 vs. 135.1 s, p = 0.016). Furthermore, the NGW group had higher maximum friction (34.6 ± 1.34 vs. 30.2 ± 4.09), lower stiffness, and better elastic resiliency. In the multivariate analysis, a curved-tip GW (OR = 0.26, 95% CI 0.11-0.62, p = 0.002) and normal papillary shape (OR = 0.39, 95% CI 0.17-0.86, p = 0.021) were contributing factors for successful selective biliary cannulation., Conclusions: The NGW group had high friction and low stiffness, characteristics affecting biliary cannulation. Clinically, the NGW group had similar success and adverse event rates as the CGW, but they showed a higher number of ampulla contacts and longer cannulation time.

Purpose: There are no effective treatment methods with which to control complications of radiation proctitis with fistula or recurrent bleeding following radiation treatment for prostate, cervical, or rectal cancer. Mesenchymal stem cells (MSCs) can induce immune modification, resulting in tissue repair and regeneration. Therefore, we used a rat model of radiation-induced proctitis and observed the effects of using human placenta-derived (PD) and adipose tissue-derived (AD) MSCs., Materials and Methods: Female Sprague Dawley rats were irradiated at the pelvic area with 25 Gy. We injected 1×10 6 cells of human PD-MSCs, human AD-MSCs, human foreskin fibroblasts, and control media into the rectal submucosa following irradiation. We sacrificed rats for pathologic evaluation., Results: Fibrosis on the rectum was reduced in both MSC groups, compared to the control group. Mucosal Ki-67 indices of both MSC injected groups were higher than those in the control group. Although caspase-3 positive cells in the mucosa gradually increased and decreased in the control group, those in both MSC injected groups increased rapidly and decreased thereafter., Conclusion: We demonstrated the effects of regional MSC injection treatment for radiation-induced proctitis in rats. MSC injection reduced fibrosis and increased proliferation in rat mucosa. Human AD-MSCs and PD-MSCs had similar effectiveness., Competing Interests: The authors have no potential conflicts of interest to disclose., (© Copyright: Yonsei University College of Medicine 2023.)

Background: This study was conducted to evaluate the clinical feasibility of nab-paclitaxel plus gemcitabine-cisplatin triplet chemotherapy in patients with locally advanced cholangiocarcinoma in real-world practice., Methods: We retrospectively reviewed patients with locally advanced cholangiocarcinoma who were treated with nab-paclitaxel plus gemcitabine-cisplatin between October 2019 and August 2021 at a single institution. The initial diagnosis of cholangiocarcinoma was histologically confirmed., Results: One hundred twenty-nine patients were included in this study. Among the patients with a measurable lesion (57.4%), the objective response rate and disease control were 60.8% and 91.9%, respectively. Seventy-seven patients (59.7%) were determined as resectable after triplet chemotherapy, but 73 (56.6%) underwent subsequent curative surgery. The major postoperative complication rate was 15.1%, and there were 2 postoperative mortalities (2.7%). There were 6 complete remission cases (8.2%) in the final pathology. The R0 resection was achieved in 67 patients (91.8%). Despite the initial locally advanced cholangiocarcinoma, a pathologic T stage of less than T2 was reported in 67 patients (91.8%). Fifty-two patients (71.2%) had no lymph node metastasis. Patients who underwent surgery after triplet chemotherapy had significantly higher 12-month overall survival (95.9% vs 76.8%; P < .001) than those treated with chemotherapy alone., Conclusion: Nab-paclitaxel plus gemcitabine-cisplatin chemotherapy demonstrated a down-staging effect through a high response rate, indicating that this triplet chemotherapy is feasible as induction therapy in patients with locally advanced cholangiocarcinoma., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Anomalous transport responses, dictated by the nontrivial band topology, are the key for application of topological materials to advanced electronics and spintronics. One promising platform is topological nodal-line semimetals due to their rich topology and exotic physical properties. However, their transport signatures have often been masked by the complexity in band crossings or the coexisting topologically trivial states. Here we show that, in slightly hole-doped SrAs 3 , the single-loop nodal-line states are well-isolated from the trivial states and entirely determine the transport responses. The characteristic torus-shaped Fermi surface and the associated encircling Berry flux of nodal-line fermions are clearly manifested by quantum oscillations of the magnetotransport properties and the quantum interference effect resulting in the two-dimensional behaviors of weak antilocalization. These unique quantum transport signatures make the isolated nodal-line fermions in SrAs 3 desirable for novel devices based on their topological charge and spin transport., (© 2022. The Author(s).)

Background: Endoscopic access to the targeted site is a major challenge for the endoscopic retrograde cholangiopancreatography (ERCP) in patients undergoing Roux-en-Y (R-Y) reconstruction after total or subtotal gastrectomy. We aimed to evaluate the feasibility, reproducibility, and safety of mechanistic loop resolution strategies using a short-type single-balloon enteroscopy (short SBE) system., Methods: Between February 2020 and March 2022, consecutive patients with a previous R-Y gastrectomy requiring ERCP were prospectively enrolled. Different mechanistic loop resolution strategies for two-dimensional loops, three-dimensionally rotated loops, and loops making a cane or S-shape were applied during the SBE approach., Results: Forty-three short SBE-ERCP procedures were performed on 37 patients, with an approach success rate of 100.0% (43/43). The mean time to reach the jejunojejunal anastomosis and target site were 8.0 (6.0-11.0) minutes and 26.0 (16.0-36.0) minutes, respectively. The major challenges for the approach were the cane or S-shaped loop in the jejunojejunal anastomosis or Treitz ligament. The retroflex positioning of a SBE in front of the papilla was achieved in 86.0% (37/43), and the cannulation success rate in patients with an intact papilla was 90.9% (30/33). The initial, overall therapeutic successes, median total procedure time, and adverse event rate were 87.8%, 92.7%, 77.0 (IQR 56-100.5) minutes, and 11.6%, respectively., Conclusions: Short SBE-ERCP using standardized mechanistic loop resolution strategies is effective and reproducible in patients with R-Y reconstruction after gastrectomy., Trial Registration: ClinicalTrial.gov (NCT04847167)., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Prophylactic pancreatic stenting effectively reduces the rate and severity of post-ERCP pancreatitis (PEP) in the precut technique; however, studies on the optimal type and duration of the stent are still lacking. This prospective study evaluated the incidence and severity of PEP and the rate of spontaneous stent dislodgement in patients undergoing transpancreatic precut sphincterotomy (TPS) accompanied by prophylactic pancreatic stenting with an unflanged plastic stent (4F × 5 cm) for difficult biliary cannulation. A total of 247 patients with naïve papilla were enrolled in this study, and data were collected prospectively. In the final analysis, 170 and 61 patients were included in the standard cannulation technique and TPS groups, respectively. The incidence of PEP in the standard cannulation technique and TPS groups was 3.5% and 1.6% ( p = 0.679), respectively. The technical success rate of selective biliary cannulation in the TPS group was 91.8%. The spontaneous dislodgement rate of the prophylactic plastic stent was 98.4%. In conclusion, an unflanged pancreatic stent (4F × 5 cm) placement in TPS for patients with failed standard cannulation technique is a safe and effective measure due to low adverse events and few additional endoscopic procedures for removing the pancreatic duct (PD) stent.

The use of endobiliary radiofrequency ablation (RFA) to generate a benign biliary stricture (BBS) model has a significant reproducibility problem. The aims of this animal study were to create an optimal BBS model using endobiliary RFA and determine the best way to develop it. The first step was performed on the common bile duct (CBD) of 10 miniature pigs using endoscopic RFA with a target temperature-controlled mode (80 ℃, 7 W for 90 s). The second step was performed on the CBD of five miniature pigs to understand more about the time-dependent changes in BBS development and the causes of adverse events. Using the conditions and techniques identified in the previous steps, the third step was conducted to create an optimal BBS model in 12 miniature pigs. In the first trial, four out of 10 animals died (40%) after the procedure due to cholangitis-induced sepsis. Based on this, biliary obstruction was prevented in further steps by placing a biliary plastic stent after RFA application. Histologic examinations over time showed that a severe abscess developed at the RFA application site on the fifth day, followed by fibrosis on the tenth day, and completion on the twentieth day. In the third trial, 11 animals survived (91.7%), the average BBS fibrotic wall thickness was 1107.9 µm (763.1-1864.6 µm), and the degree of upstream biliary dilation was 14.4 mm (11.05-20.7 mm). In conclusion, endobiliary RFA combined with a biliary plastic stent resulted in a safe and reproducible BBS animal model., (© 2022. The Author(s).)

Refractory functional dyspepsia (RFD) is diagnosed when symptoms persist for at least 6 months despite at least two medical treatments. No consensus treatment guidelines exist. The implicated causes of functional biliary dyspepsia are a narrowed cystic duct, Sphincter of Oddi dysfunction, microlithiasis, and gallbladder dyskinesia. We investigated the treatment effects of litholytic agents. RFD patients were prospectively enrolled in six tertiary medical centers. All subjects took chenodeoxycholic and ursodeoxycholic acids (CNU) twice daily for 12 weeks. We monitored their medication adherence, laboratory results, and complications. The 7-point global symptom scale test scores were determined before and after treatment. Of the 52 patients who were prospectively screened, 37 were included in the final analysis. The mean age was 51.3 years: 14 were males, and 23 were females. Before treatment, the mean number and duration of symptoms were 2.4 and 48.2 months, and a mean of 3.3 FD-related drugs were taken. The mean CNU adherence was 95.3%. The mean global symptom scale score decreased from 5.6 pretreatment to 2.6 posttreatment. The symptom improvement rate was 94.6% (35 out of 37 patients). The only adverse event was mild diarrhea (10.8%) that was resolved after conservative management. Conclusions: CNU improved the symptoms of RFD patients who did not respond to conventional medications. Litholytic agents are good treatment options for patients with RFD and biliary dyspepsia secondary to biliary microlithiasis. Further prospective, large-scale mechanistic studies are warranted.

Background: Fibroblasts produce collagen molecules that support the structure of the skin. The decrease and hypersynthesis of collagen causes skin problems such as skin atrophy, wrinkles and scars., Objective: The purpose of this study is to investigate the mechanism of mitoxantrone on collagen synthesis in fibroblasts., Methods: Cultured fibroblasts were treated with mitoxantrone, and then collagen synthesis was confirmed by reverse transcription-polymerase chain reaction and Western blot., Results: Mitoxantrone inhibited the expression of type I collagen in fibroblasts at both the mRNA and protein levels. In the collagen gel contraction assay, mitoxantrone significantly inhibited gel contraction compared to the control group. Mitoxantrone inhibited transforming growth factor (TGF)-β-induced phosphorylation of SMAD3. Finally, mitoxantrone inhibited the expression of LARP6, an RNA-binding protein that regulates collagen mRNA stability., Conclusion: These results suggest that mitoxantrone reduces collagen synthesis by inhibiting TGF-β/SMAD signaling and LARP6 expression in fibroblasts, which can be developed as a therapeutic agent for diseases caused by collagen hypersynthesis., Competing Interests: CONFLICTS OF INTEREST: The authors have nothing to disclose., (Copyright © The Korean Dermatological Association and The Korean Society for Investigative Dermatology.)

Background: Intraductal papillary neoplasm of the bile duct (IPNB) is a precancerous lesion of cholangiocarcinoma, for which surgical resection is the most effective treatment. We evaluated the predictors of malignancy in IPNB according to anatomical location and the prognosis without surgery. Methods: A total of 196 IPNB patients who underwent pathologic confirmation by surgical resection or endoscopic retrograde cholangiography or percutaneous transhepatic cholangioscopic biopsy were included. Clinicopathological findings of IPNB with invasive carcinoma or mucosal dysplasia were analyzed according to anatomical location. Results: Of the 116 patients with intrahepatic IPNB (I-IPNB) and 80 patients with extrahepatic IPNB (E-IPNB), 62 (53.4%) and 61 (76.3%) were diagnosed with invasive carcinoma, respectively. Multivariate analysis revealed that mural nodule > 12 mm (p = 0.043) in I-IPNB and enhancement of mural nodule (p = 0.044) in E-IPNB were predictive factors for malignancy. For pathologic discrepancy before and after surgery, IPNB has a 71.2% sensitivity and 82.3% specificity. In the non-surgical IPNB group, composed of nine I-IPNB and seven E-IPNB patients, 43.7% progressed to IPNB with invasive carcinoma within 876 days. Conclusions: E-IPNB has a higher rate of malignancy than I-IPNB. The predictive factor for malignancy is mural nodule > 12 mm in I-IPNB and mural nodule enhancement in E-IPNB.

Purpose: The current drain tubes for preventing surgically biliary anastomotic stricture are not naturally and easily removed. If a drain tube using biodegradable material is easily available and the degradation time of the tube is well controlled, surgical anastomotic stricture and fibrosis could be prevented. The aim of this animal study was to evaluate the preventive effect of novel biodegradable stents (BS) on biliary stricture and fibrosis after duct-to-duct (DD) biliary anastomosis., Methods: Ten mini-pigs were allocated to the control group (n = 5) and or the stent group (n = 5). The common bile duct was exposed through surgical laparotomy and then resected transversely. In the stent group, a 4-mm or 6-mm polydioxanone/magnesium sheath-core BS was inserted according to the width of the bile duct, followed by DD biliary anastomosis. In the control group, DD biliary anastomosis was performed without BS insertion., Results: In the stent group, stents were observed without deformity for up to 4 weeks in all animals. Eight weeks later, histopathologic examination revealed that the common bile duct of the anastomosis site was relatively narrower in circumference in the control group compared to the stent group. The degree of fibrosis in the control group was more marked than in the stent group (3.84 mm vs. 0.68 mm, respectively; P < 0.05)., Conclusion: Our study showed that novel BS maintained their original shape and radial force for an adequate time and then disappeared without adverse events. The BS could prevent postoperative complications and strictures after DD biliary anastomosis., Competing Interests: Conflict of Interest: Kyu Seok Kim, Jong Pil Moon, Sehwan Park, and Jinkyung Jeon are researchers at the Interventional Research Center of M.I.Tech Co., Ltd. which provided the prototype biodegradable stents used in our experiment. The other authors have no conflicts of interest to disclose., (Copyright © 2022, the Korean Surgical Society.)

Complex electronic phases in strongly correlated electron systems are manifested by broken symmetries in the low-energy electronic states. Some mysterious phases, however, exhibit intriguing energy gap opening without an apparent signature of symmetry breaking (e.g., high- T C cuprates and heavy fermion superconductors). Here, we report an unconventional gap opening in a heterostructured, iron-based superconductor Sr 2 VO 3 FeAs across a phase transition at T 0 ∼150 K. Using angle-resolved photoemission spectroscopy, we identify that a fully isotropic gap opens selectively on one of the Fermi surfaces with finite warping along the interlayer direction. This band selectivity is incompatible with conventional gap opening mechanisms associated with symmetry breaking. These findings, together with the unusual field-dependent magnetoresistance, suggest that the Kondo-type proximity coupling of itinerant Fe electrons to localized V spin plays a role in stabilizing the exotic phase, which may serve as a distinct precursor state for unconventional superconductivity., Competing Interests: The authors declare no competing interest., (Copyright © 2021 the Author(s). Published by PNAS.)

Objectives: The clinical outcomes and prevalence of adverse events associated with biliary biodegradable stents (BS) can differ according to degradation process and time. The aim of this study was to observe the degradation process and time of different BS prototypes, and to evaluate sequential changes in their mechanical properties., Methods: Using an in vitro bile flow phantom model, we compared degradation time, radial force changes, and morphologic changes among four different BS prototypes: polydioxanone (PDO) BS, polyglycolide (PGA) BS, polydioxanone/poly-l-lactic acid (PDO/PLLA) sheath-core BS, and polydioxaone/magnesium (PDO/Mg) sheath-core BS. Using an in vivo swine bile duct dilation model, we performed a direct peroral cholangioscopy (DPOC) examination to observe the biodegradation process and related adverse events at regular intervals., Results: In the bile flow phantom model, the PGA BS and PDO/Mg BS prototypes showed rapid radial force reduction and morphological changes and complete degradation within six weeks. PDO/PLLA BS maintained high radial force and kept their original shape for longer than the PDO BS, up to 16 weeks. A total of 24 BS were inserted into the dilated bile ducts of 12 swine. In this animal model, DPOC examination revealed that PDO BS and PDO/PLLA BS maintained their original shapes for approximately 12 weeks, but PDO BS showed a greater degree of fragmentation and induced biliary stones and bile duct obstruction., Conclusion: Our results showed that PDO/PLLA BS maintained their original shape and radial force for a relatively long time and minimized adverse events., (© 2020 Japan Gastroenterological Endoscopy Society.)

Background and Aims: Endobiliary brushings are routinely used in the diagnosis, treatment, and prognostication of biliary strictures. However, standard Papanicolaou (Pap) staining has a low sensitivity in this setting, and the accuracy of brush cytology has not been established for indeterminate strictures. We therefore evaluated the diagnostic merit of methionyl-transfer RNA synthetase 1 (MARS1) immunofluorescence (IF) staining in such cytologic specimens., Methods: During ERCP, endobiliary brushings were obtained from patients with extrahepatic biliary strictures prospectively enrolled at 6 tertiary hospitals. Using liquid-based cytologic preparations of these samples, we performed Pap and MARS1 IF staining., Results: In total, 240 patients were eligible; of these, we compared the Pap and MARS1 IF staining results of 218 (malignant, 157; benign, 61). By conventional Pap staining, the diagnoses were distributed as follows: malignant, 55; suspicious of malignancy, 60; atypical, 45; negative for malignancy, 58. MARS1 IF staining was strongly positive in malignant biliary stricture but not so in specimens negative for malignancy. The diagnostic parameters (sensitivity, specificity, positive predictive value, negative predictive value, and accuracy) of the MARS1 IF (93.6%, 96.7%, 98.7%, 85.5%, and 94.5%, respectively) and conventional Pap (73.2%, 100%, 100%, 59.2%, and 80.7%, respectively) staining methods differed significantly (P < .0001)., Conclusions: The high sensitivity and accuracy of MARS1 IF staining enabled the detection of malignancy in patients with biliary strictures. Further prospective studies are needed to validate our findings. (Clinical trial registration number: NCT03708445.)., (Copyright © 2021 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background: A recent phase II trial reported prolonged survival in patients with advanced biliary tract cancer (BTC) following treatment with nab-paclitaxel plus gemcitabine-cisplatin (Gem/Cis/nab-P). We aimed to evaluate the clinical outcomes of Gem/Cis/nab-P in Asian patients with advanced BTC in a real-world setting., Methods: We reviewed the data of patients who received Gem/Cis/nab-P for the management of advanced BTC between September 2019 and April 2021 at four institutes in Korea. Patients were classified into the Gem/Cis/nab-P and nab-P addition groups depending on the starting point of nab-P administration., Results: A total of 178 patients treated with Gem/Cis/nab-P were included in the study. Of these, 43.8% had intrahepatic cholangiocarcinoma (CCA), 34.8% had extrahepatic CCA, and 21.3% had gall bladder cancer. A total of 117 (65.7%) patients received Gem/Cis/nab-P as the first-line treatment, while 61 (34.3%) were treated with gemcitabine-cisplatin-based chemotherapy followed by nab-P addition. The objective response rate (ORR) and disease control rate in all patients were 42.1% and 84.8%, respectively. The ORR in the Gem/Cis/nab-P group was 47.9%, while that in the nab-P addition group was 31.1%. The median progression-free survival and overall survival were 8.5 months [95% confidence interval (CI), 6.9-10.1] and 14.6 months (95% CI, 10.2-19.0), respectively. In patients who received Gem/Cis/nab-P as initial treatment, the median PFS was 9.4 months (95% CI, 7.9-10.9) and the median OS was not-reached (95% CI, not available). Anemia ( n  = 42, 23.6%), neutropenia ( n  = 40, 22.5%), and thrombocytopenia ( n  = 16, 9.0%) were the most common grade 3-4 toxicities. A total of 20 patients (11.2%) had conversions from unresectable to resectable disease and underwent surgery with curative intent., Conclusion: Gem/Cis/nab-P showed favorable real-life efficacy and safety outcomes in Korean patients with advanced BTC, which was consistent with the phase II trial outcomes., Competing Interests: Conflict of interest statement: HJ.Chon has a consulting or advisory role at Roche, Bayer, Eisai, ONO, BMS, and MSD. J.Cheon received honoraria from Bayer, Eisai, Ipsen, MSD, BMS and Roche. All other authors have no potential conflicts of interest to declare., (© The Author(s), 2021.)

Background and Aim: Endoscopic post-papillectomy bleeding occurs in 3% to 20% of the cases, and delayed bleeding is also problematic. However, there is no consensus on how to reduce delayed post-papillectomy bleeding. The aim of this study was to evaluate the efficacy of prophylactic argon plasma coagulation (APC) to minimize delayed bleeding and reduce the persistence of residual tumors after endoscopic papillectomy., Methods: In a prospective pilot study of patients with benign ampullary tumors, the prophylactic APC group underwent APC at the resection margin following a conventional snaring papillectomy. Then, 24 h later after the papillectomy, all patients underwent a follow-up duodenoscopy to identify post-papillectomy bleeding and were followed up until 12 months. The main outcomes were the delayed (≥24 h) post-papillectomy bleeding rate and the tumor persistence rate., Results: The delayed post-papillectomy bleeding rate was 30.8% (8/26) in the prophylactic APC group and 21.4% (6/28) in the non-APC group (P = 0.434). The post-procedure pancreatitis rates were 23.1% (6/26) and 35.7% (10/28), respectively (P = 0.310). The rate of tumor persistence did not differ between the two groups at 1 month (12.5% vs 7.4%, P = 0.656), 3 months (4.2% vs 3.7%, P = 1.00), 6 months (8.3% vs 3.7%, P = 0.595), and 12 months (0% vs 3.7%, P = 1.00). There were no procedure-related mortalities or serious complications., Conclusion: Prophylactic APC may not be effective in reducing delayed post-papillectomy bleeding or remnant tumor ablation immediately after conventional papillectomy (Clinical trial registration-cris.nih.go.kr; KCT0001955)., (© 2020 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

Purpose: Repeating endoscopic retrograde cholangiopancreatography (ERCP) in patients with recurrent common bile duct (CBD) stones is problematic in many ways. Choledochoduodenostomy (CDS) and choledochojejunostomy (CJS) are 2 surgical treatment options for recurrent CBD stones, and each has different advantages and disadvantages. The aim of this study was to compare the 2 surgical options in terms of the recurrence rate of CBD stones after surgical treatment., Methods: This retrospective multicenter study included all patients who underwent surgical treatment due to recurrent CBD stones that were not effectively controlled by medical treatment and repeated ERCP between January 2006 and March 2015. We collected data from chart reviews and medical records. A recurrent CBD stone was defined as a stone found 6 months after the complete removal of a CBD stone by ERCP. Patients who underwent surgery for other reasons were excluded., Results: A total of 27 patients were enrolled in this study. Six patients underwent CDS, and 21 patients underwent CJS for the rescue treatment of recurrent CBD stones. The median follow-up duration was 290 (180-1,975) days in the CDS group and 1,474 (180-6,560) days in the CJS group (P = 0.065). The postoperative complications were similar and tolerable in both groups (intestinal obstruction; 2 of 27, 7.4%; 1 in each group). CBD stones recurred in 4 patients after CDS (4 of 6, 66.7%), and 3 patients after CJS (3 of 21, 14.3%) (P = 0.010)., Conclusion: CJS may be a better surgical option than CDS for preventing further stone recurrence in patients with recurrent CBD stones., Competing Interests: Conflict of Interest: No potential conflict of interest relevant to this article was reported., (Copyright © 2020, the Korean Surgical Society.)

Biliary dyspepsia presents as biliary colic in the absence of explanatory structural abnormalities. Causes include gallbladder dyskinesia, sphincter of Oddi dysfunction, biliary tract sensitivity, microscopic sludges, and duodenal hypersensitivity. However, no consensus treatment guideline exists for biliary dyspepsia. We investigated the effects of medical treatments on biliary dyspepsia.We retrospectively reviewed the electronic medical records of 414 patients who had biliary pain and underwent cholescintigraphy from 2008 to 2018. We enrolled patients who received litholytic agents and underwent follow-up scans after medical treatment. We divided the patients into the GD group (biliary dyspepsia with reduced gallbladder ejection fraction [GBEF]) and the NGD group (biliary dyspepsia with normal GBEF). We compared pre- and post-treatment GBEF and symptoms.Among 57 patients enrolled, 40 (70.2%) patients had significant GBEF improvement post-treatment, ranging from 34.4 ± 22.6% to 53.8 ± 26.8% (P < .001). In GD group (n = 35), 28 patients had GBEF improvement after medical treatment, and value of GBEF significantly improved from 19.5 ± 11.0 to 47.9 ± 27.3% (P < .001). In NGD group (n = 22), 12 patients had GBEF improvement after medical treatment, but value of GBEF did not have significant change. Most patients (97.1% in GD group and 81.8% in NGD group) had improved symptoms after medical treatment. No severe complication was reported during treatment period.Litholytic agents improved biliary colic in patients with biliary dyspepsia. Therefore, these agents present an alternative treatment modality for biliary dyspepsia with or without gallbladder dyskinesia. Notably, biliary colic in patients with gallbladder dyskinesia resolved after normalization of the GBEF. Further prospective and large-scale mechanistic studies are warranted.

Background/aims: Endoscopic retrograde cholangiopancreatography (ERCP) is used as a curative method for choledocholithiasis, but little is known about ERCP for patients with end-stage renal disease (ESRD) on hemodialysis (HD). The aim of the current study was to evaluate the efficacy and safety of ERCP for patients with ESRD on HD and to identify the risk factors of ERCP-related bleeding., Materials and Methods: The medical records of 61 ESRD patients with choledocholithiasis who underwent ERCP were retrospectively investigated with respect to successful bile duct stone removal and procedure-related adverse events such as pancreatitis, bleeding, and cholangitis., Results: For the study subjects, the overall stone removal success rate was 96.7%, and the overall ERCP-related adverse event rate was 21.3% (pancreatitis, 4.9%; bleeding, 13.1%; cholangitis, 6.6%). Endoscopic sphincterotomy (EST) was found to be associated with hemorrhage (p=0.02), and the occurrence of hemorrhage in patients who underwent EST with or without endoscopic papillary balloon dilation (EPBD) was significantly higher than that in patients who underwent EPBD alone (Odds ratio 1.27, 95% confidence interval 1.075-1.493, p=0.02)., Conclusion: ERCP for ESRD patients was found to be feasible and safe. However, EST was significantly related to hemorrhagic events. EPBD reduced the risk of hemorrhage and was as effective as EST in terms of stone removal.

Background: Arthroscopic labral repair combined with capsular plication decreases joint volume and restores glenoid labral bumper height; thus, the procedure helps decrease capsular redundancy. However, the decreased volume and restored glenoid labral bumper height could change over time, which could influence the outcome of the operation., Purpose: To (1) measure glenoid labral bumper height and capsular volume quantitatively in serial computed tomography arthrography (CTA) and evaluate the relationship between bumper height and joint volume and (2) compare the difference in bumper height and joint volume between groups with and without apprehension after arthroscopic Bankart repair., Study Design: Case-control study; Level of evidence, 3., Methods: Patients who had undergone arthroscopic Bankart repair between January 2012 and June 2016, and were assessed by CTA 3 to 6 months and 12 to 18 months after the operation were included. An image reconstruction program (3-dimensional slicer) was used to calculate inferior, anterior-inferior, and posterior-inferior joint volumes; the ratio of the anterior-inferior volume to the inferior volume was defined as the anterior-inferior volume fraction (VF AI ). We also measured glenoid labral bumper height at the 5-, 4-, and 3-o'clock positions., Results: A total of 50 patients were enrolled as study participants (mean age, 25.2 ± 9.29 years). Of these, 10 patients had either redislocation or apprehension, and 40 patients had neither. A significant correlation was observed between 5-o'clock glenoid labral bumper height and VF AI on early CTA (3-6 months) and late CTA (12-18 months) (early CTA: Pearson coefficient, -0.335, P = .040; late CTA: Pearson coefficient, -0.468, P = .003). VF AI at the early CTA was 42.20 ± 10.15 in the group with apprehension and 33.49 ± 9.66 in the group without apprehension; a significant difference was observed. VF AI at the late CTA was 45.84 ± 11.97 in the group with apprehension and 37.65 ± 9.70 in the group without apprehension and thus showed a significant difference between the 2 groups. However, the 3-, 4-, and 5-o'clock glenoid labral bumper heights on early and late CTAs did not show a statistically significant difference between the 2 groups., Conclusion: Early postoperative VF AI is related to postoperative apprehension and redislocation and might be reduced by increasing the 5-o'clock glenoid labral bumper height.

Background: ERCP training models are very different in terms of anatomical differences, ethical issues, storage problems, realistic tactile sensation, durability and portability. There is no easy way to select an optimized model for ERCP training. If the ERCP training model could be made as a soft silicone model using 3D printing technique, it would have numerous advantages over the models presented so far. The purpose of this study was to develop an optimized ERCP training model using a 3D printing technique and to try to find ways for implementing various practical techniques., Methods: All organ parts of this model were fabricated using silicone molding techniques with 3D printing. Especially, various anatomy of the ampulla of Vater and common bile duct (CBD) were creatively designed for different diagnostic and therapeutic procedures. In order to manufacture each of the designed organ parts with silicone, a negative part had to be newly designed to produce the molder. The negative molders were 3D printed and then injection molding was applied to obtain organ parts in silicone material. The eight different types of ampulla and CBD were repeatedly utilized and replaced to the main system as a module-type., Results: ERCP training silicone model using 3D technique was semi-permanently used to repeat various ERCP procedures. All ERCP procedures using this model could be observed by real-time fluoroscopic examination as well as endoscopic examination simultaneously. Using different ampulla and CBD modules, basic biliary cannulation, difficult cannulation, stone extraction, mechanical lithotripsy, metal stent insertion, plastic stent insertion, and balloon dilation were successfully and repeatedly achieved. Endoscopic sphincterotomy was also performed on a specialized ampulla using a Vienna sausage. After repeat procedures and trainings, all parts of organs including the ampulla and CBD modules were not markedly damaged or deformed., Conclusions: We made a specialized ERCP training silicon model with 3D printing technique. This model is durable, relatively cheap and easy to make, and thus allows the users to perform various specialized ERCP techniques, which increases its chances of being a good ERCP training model.

Objectives: Successful biliary cannulation is a prerequisite and important component of endoscopic retrograde cholangiopancreatography, but conventional cannulation methods (CCMs) have a postendoscopic retrograde cholangiopancreatography pancreatitis (PEP) rate of 14.1% in patients at high risk for PEP. The aim of this study was to evaluate the effectiveness and safety of needle-knife fistulotomy (NKF), compared with a CCM, when used for primary biliary access in patients at high risk for developing PEP., Methods: A total of 207 patients with one or more risk factors for PEP were prospectively enrolled. The patients were randomly allocated to one of 2 groups according to the primary biliary cannulation technique (NKF or CCM). We compared biliary cannulation success rates, cannulation and procedure times, and the incidence of adverse events, including PEP, between the groups., Results: The mean number of PEP risk factors was similar between the groups (NKF, 2.2 ± 1.0; CCM, 2.2 ± 0.9). PEP occurred in 8 patients in the CCM group and in no patients in the NKF group (9.2% vs 0%, P < 0.001). The rates of other adverse events did not differ between the groups. The biliary cannulation success rate was high in the NKF group, but relatively low in the CCM group, possibly because of the stringent failure criteria aimed at reducing PEP. However, the mean cannulation and total procedural times were longer in the NKF group than in the CCM group., Discussion: NKF is an effective and safe procedure to gain primary biliary access in patients at high risk for developing PEP. ClinicalTrials.gov, NCT02916199.

Background: Balloon enteroscopy-assisted endoscopic retrograde cholangiopancreatography (BE-ERCP) has been reported to be effective for patients with surgically altered gastrointestinal anatomy. However, selective biliary cannulation remains difficult in BE-ERCP. We examined the usefulness of a modified double-guidewire technique using an uneven double lumen cannula (the uneven method) for BE-ERCP in patients with surgically altered gastrointestinal anatomy., Methods: To clarify the usefulness of the uneven method for selective biliary cannulation in BE-ERCP in comparison to the pancreatic guidewire (PGW) method, 40 patients with surgically altered gastrointestinal anatomy who underwent BE-ERCP with successful placement of a guidewire in the pancreatic duct were evaluated. The uneven method was used in 18 cases (uneven group) and the PGW method was used in the remaining 22 cases (PGW group)., Results: The technical success rate of biliary cannulation was higher in the uneven group than in the PGW group (83.3 vs. 59.0%; P = 0.165). In addition, the time to biliary cannulation were significantly shorter in the uneven group than in the PGW group (6 vs. 18 min; P = 0.004; respectively). In the PGW group, post-ERCP pancreatitis (PEP) occurred in 3 of 22 cases (13.6%). No adverse events, including PEP, occurred in the uneven group., Conclusions: The uneven method may be a useful option of selective biliary cannulation in BE-ERCP for the patients with surgically altered gastrointestinal anatomy.

Background and Aims: EUS elastography is a real-time imaging technique that analyzes tissue elasticity. The aim of this study was to investigate the applicability of quantitative EUS elastography in the differential diagnosis of gastric subepithelial tumors (SETs)., Methods: We prospectively registered 41 consecutive patients with gastric SETs and measured their strain ratios with EUS elastography. The strain ratios of gastric SETs were compared with the histopathologic diagnosis., Results: Thirty-one patients (mean age, 51.4 ± 12.6 years) were included in the analysis. The mean size of the SETs was 2.3 ± 0.7 cm. Lipomas had the lowest strain ratio of 1.6 (1.1-2.0), followed by leiomyomas 6.0 (2.0-29.0), ectopic pancreas 11.8 (1.7-29.3), gastrointestinal stromal tumors (GISTs) 51.1 (29.0-67.0), and schwannomas 62.0. With a cut-off value of 22.7, EUS elastography could differentiate GISTs from leiomyomas with sensitivity and specificity of 100% and 94.1%, respectively (P = .001; 95% confidence interval, 0.979-1.000)., Conclusions: EUS elastography could be a promising diagnostic adjunct for the assessment of gastric SETs, especially in differentiating GISTs from leiomyomas., (Copyright © 2020 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background/aims: Using an appropriate guidewire can increase the success rate of selective cannulation in endoscopic retrograde cholangiopancreatography. The purpose of this technical study was to investigate the characteristics of each guidewire type and to evaluate its efficiency and rapidity of insertion., Methods: We conducted a three-point bending test using a universal testing machine to investigate the flexibility and bending features of each guidewire. 3D-printed silicone tubes with various types of stricture and a hand-made biliary tree silicone model with six-stranded intrahepatic ducts were used to evaluate the success rate and insertion time of each guidewire., Results: In the three-point bending test, the characteristics of each guidewire were classified. We found that the bending strengths and times were independent of shaft thickness. Using two in vitro biliary duct models, we determined that the success rate and total insertion time were better for guidewires with a resilient shaft and angled tip than for other types of guidewires (p<0.001). Although thickness of the guidewire affected the success rate (p<0.05), it did not affect the total insertion time (p≥0.05)., Conclusion: Among several types of guidewire, some factors (resilient shaft, highly flexible, and angled tip) appeared to be associated with the efficiency and rapidity of the guidewire insertion.

We demonstrate that the excitonic insulator ground state of Ta&#95;{2}NiSe&#95;{5} can be electrically controlled by electropositive surface adsorbates. Our studies utilizing angle-resolved photoemission spectroscopy reveal intriguing wave-vector-dependent deformations of the characteristic flattop valence band of this material upon potassium adsorption. The observed band deformation indicates a reduction of the single-particle band gap due to the Stark effect near the surface. The present study provides the foundation for the electrical tuning of the many-body quantum states in excitonic insulators.

Pancreatic cancer is a major cause of cancer-related mortality and morbidity, and its incidence is increasing as the population is aging. On the other hand, significant improvement in the prognosis has not occurred. The absence of early diagnosis means that many patients are diagnosed only when they develop symptoms, such as jaundice, due to a biliary obstruction. The role of endoscopy in multidisciplinary care for patients with pancreatic cancer continues to evolve. Controversy remains regarding the best preoperative biliary drainage in patients with surgically resectable pancreatic head cancer. In general, patients undergoing a surgical resection usually do not require preoperative biliary drainage unless they have cholangitis or receive neoadjuvant chemotherapy. If biliary drainage is performed prior to surgery, the patient's condition and a multidisciplinary approach should be considered. With the increasing life expectancy of patients with pancreatic cancer, the need for more long-time biliary drainage or pre-operative biliary drainage is also increasing. Strong evidence of endoscopic retrograde cholangiopancreatography (ERCP) as a first-line and essential treatment for biliary decompression has been provided. On the other hand, the use of endoscopic ultrasound-guided biliary drainage as well as percutaneous biliary drainage has been also recommended. During ERCP, self-expandable metal stent could be recommended instead of a plastic stent for the purpose of long stent patency and minimizing stent-induced complications. In this review, several points of view regarding the relief of obstruction in patients with pancreatic cancer, and optimal techniques are being discussed.

Background: The adoption of minimally invasive surgery for transduodenal ampullectomy has been slow because of special characteristics and complexity of this procedure., Methods: Six patients underwent robotic transduodenal ampullectomy. We employed novel methods to facilitate exposure of the ampulla., Results: All patients completed robotic transduodenal ampullectomy, but one patient was immediately converted to robotic pancreaticoduodenectomy because of presence of invasive carcinoma on frozen biopsy. The final pathologic report revealed high-grade dysplasia in four patients, low-grade dyplasia in one, and T2N0 in one patient who converted to pancreaticoduodenectomy. There was no immediate postoperative complication or mortality. One patient was readmitted after 3 months because of stricture of the bile duct outlet. There was no recurrence over a median follow-up period of 20 months., Conclusion: An appropriate combination of patient positioning and retraction method helps the robot surgical system to provide competent performance for sophisticated and precise manipulation of ampullary lesions., (© 2018 John Wiley & Sons, Ltd.)

Background/aims: Recently, to lower the production costs and risk of infection, new disposable biopsy forceps made using simple manufacturing techniques have been introduced. However, the effects of the manufacturing techniques are unclear. The aim of this study was to evaluate which types of biopsy forceps could obtain good-quality specimens according to the manufacturing techniques., Methods: By using an in vitro nitrile glove popping model, we compared the popping ability among eight different disposable biopsy forceps (one pair of biopsy forceps with cups made by a cutting method [cutting forceps], four pairs of biopsy forceps with cups made by a pressing method [pressing forceps], and three pairs of biopsy forceps with cups made using a injection molding method [molding forceps]). Using an in vivo swine model, we compared the penetration depth and quality of specimen among the biopsy forceps., Results: In the in vitro model, the molding forceps provided a significantly higher popping rate than the other forceps (cutting forceps, 25.0%; pressing forceps, 17.5%; and molding forceps, 41.7%; p = 0.006). In the in vivo model, the cutting and pressing forceps did not provide larger specimens, deeper biopsy specimen, and higher specimen adequacy than those obtained using the molding forceps (p = 0.2631, p = 0.5875, and p = 0.2147, respectively). However, the molding forceps showed significantly more common crush artifact than the others (cutting forceps, 0%; pressing forceps, 5.0%; and molding forceps, 43.3%; p = 0.0007)., Conclusion: The molding forceps provided lower performance than the cutting and pressing forceps in terms of crush artifact.

Chronic pancreatitis is a chronic condition characterized by pancreatic inflammation that causes fibrosis and the destruction of exocrine and endocrine tissues. Chronic pancreatitis is a progressive disease, and no physiological treatment is available to reverse its course. However, with advances in medical technology, the existing diagnostic and treatment methods for chronic pancreatitis are evolving. Managing patients with chronic pancreatitis is challenging and necessitates a multidisciplinary approach. In this review, we discuss the recent advances in the diagnosis and management of chronic pancreatitis and introduce future alternative modalities.

Background: To overcome duodenobiliary reflux induced by biliary stents, antireflux valve (ARV) biliary stents have been developed and showed improvement in stent patency. However, negative study results have also been reported because stent patency may be decreased by the malfunction of ARV itself. Given such mixed results, the true efficacy of ARV remains unknown and the mechanism of its dysfunction needs to be clearly elucidated. The aim of this study was to investigate the exact mechanism of ARV dysfunction using in vitro phantom models., Methods: Two experimental models were designed to evaluate two important environmental factors suspected to cause ARV malfunction, i.e. bile flow and pH. Three types of ARV metal stents from different companies were used for the experiments: a funnel type ARV, a windsock type ARV, and a wine glass-shaped ARV. Ten stents of each type were tested (five stents in the bile flow phantom model, and another five stents in the duodenal pH environmental model). To determine ARV malfunction, ARV-induced flow resistance was measured using a custom-made testing device. All stents from the two models were removed every 2 weeks for 12 weeks after stent insertion and were evaluated on morphological and functional changes of the ARV., Results: Only ARV of wine glass-shaped ARV was morphologically changed due to silicone bond detachment in the bile flow model. All types of ARV were morphologically changed in the pH model. The morphological changes of ARV influenced the flow resistance. The antegrade pressure gradients were increased over time in the pH model (p < 0.05)., Conclusions: Morphological change of the ARVs may induce dysfunction of ARV metal stents, which is mainly due to duodenal pH environment. In the future, development of new ARV that is not affected by duodenal environmental factors can be expected to improve stent patency.

Background and Study Aims: In plastic stent insertion for treatment of post-cholecystectomy bile leak, stent migration may be more common due to the absence of a shelf to anchor the stent. We evaluated how adding a flap to straight plastic stents for this indication might influence the rate of stent migration when compared to use of conventional plastic stents., Patients and Methods: This is a retrospective study including patients referred for ERCP for treatment of post-cholecystectomy bile leak. Patients with a customized anti-migration flap stent had the additional flap created on the distal end of straight plastic stents, intended to aid in anchoring in the distal supra-sphincteric biliary duct. The primary endpoint is stent migration events. The secondary endpoint is bile leak resolution after first ERCP session., Results: Thirty-two patients were treated with the experimental additional flap stents and 225 patients were treated with standard straight biliary stents. The total failure rate of bile leak resolution after a single endoscopic treatment for all treated was 10.5 % (27/257) and the total stent migration rate for all enrolled was 15.2 % (39/257). Stent migration rate was lower in the additional flap stent group than in the conventional group (3.1 % vs. 16.9 %, respectively, P  = 0.04). Furthermore, significantly more patients had resolution of their bile leak after the first ERCP session in the group with the additional flap (100 % vs. 88 %, respectively, P  = 0.03)., Conclusion: A plastic biliary stent with an extra flap may have improved performance with regard to stent migration and resolution of bile leak over standard plastic biliary stents.

Background and Aim: In patients with irretrievable or intractable bile duct stone, temporary insertion of a plastic stent (PS) followed by further endoscopic retrograde cholangiopancreatography (ERCP) or surgery has been recommended as a 'bridge' therapy. However, the exact mechanism of stone fragmentation has not been discovered. The aim of the present study was to evaluate whether PS shape can facilitate stone fragmentation., Methods: Using a new in vitro bile flow phantom model, we compared the friction effect among three different PS groups (straight PS group, double pigtail-shaped PS group, and screw-shaped PS group) and a control group. Each group had 10 silicon tube blocks that separately contained one stone and two PS. The control group had 10 blocks each with only a stone and no PS. We carried out analysis of the friction effect by stone weight and volume changes among the groups, excluding fragmented stones., Results: After 8 weeks, complete fragmentation was noted in one out of 34 cholesterol stones (2.9%) and in four out of six pigmented stones (66.7%). Fragmentation tended to be more prominent in the screw-shaped PS group than in the straight PS group, double pigtail-shaped group, and control group (volume change: -11.33%, 7.94%, 4.43%, and 2.05%, respectively, P = 0.1390; weight change: -9.30%, 0.71%, -0.10%, and -1.23%, respectively, P = 0.3553)., Conclusion: Stone fragmentation may be induced by PS friction effect. Also, screw-shaped plastic stents may improve friction effect. These results may help guide future PS development and clinical decisions., (© 2017 Japan Gastroenterological Endoscopy Society.)

Background/aims: This study aimed to evaluate the diagnostic role of low serum amylase and lipase values in the detection of chronic pancreatitis., Methods: Patients underwent endoscopic retrograde cholangiopancreatography and were diagnosed with non-calcific chronic pancreatitis (NCCP; n=99) and calcific chronic pancreatitis (CCP; n=112). Patient serum amylase and lipase values were compared with those of healthy controls (H; n=170)., Results: The median serum amylase (normal range, 19 to 86 U/L) and lipase values (7 to 59 U/L) (P₂₅-P₇₅) were 47.0 (39.8 to 55.3) and 25.0 (18.0 to 35.0) for H, 34.0 (24.5 to 49.0) and 19.0 (9.0 to 30.0) for NCCP, and 30.0 (20.0 to 40.8) and 10.0 (3.0 to 19.0) for CCP, respectively. The cutoff values with the highest diagnostic accuracy for discriminating NCCP from H were 40 U/L for amylase and 20 U/L for lipase, respectively, and for CCP from H were 38 U/L for amylase and 15 U/L for lipase, respectively. For the diagnosis of NCCP with a criterion of serum amylase <40 and lipase <20 U/L, the sensitivity, specificity, positive predictive value, and negative predictive values were 37.4%, 88.8%, 66.1%, and 70.9%, respectively., Conclusions: Serum amylase and/or lipase levels below the normal serum range are highly specific for chronic pancreatitis patients. Clinicians should not ignore low serum pancreatic enzyme values.