Covalent versus noncovalent attachments of [FeFe]­hydrogenase models onto carbon nanotubes for aqueous hydrogen evolution reaction.

In an effort to develop the biomimetic chemistry of [FeFe]­hydrogenases for catalytic hydrogen evolution reaction (HER) in aqueous environment, we herein report the integrations of diiron dithiolate complexes into carbon nanotubes (CNTs) through three different strategies and compare the electrochemical HER performances of the as-resulted 2Fe2S/CNT hybrids in neutral aqueous medium. That is, three new diiron dithiolate complexes [{(µ-SCH2)2N(C6H4CH2C(O)R)}Fe2(CO)6] (R = N-oxylphthalimide (1), NHCH2pyrene (2), and NHCH2Ph (3)) were prepared and could be further grafted covalently to CNTs via an amide bond (this 2Fe2S/CNT hybrid is labeled as H1) as well as immobilized noncovalently to CNTs via π-π stacking interaction (H2) or via simple physisorption (H3). Meanwhile, the molecular structures of 1-3 are determined by elemental analysis and spectroscopic as well as crystallographic techniques, whereas the structures and morphologies of H1-H3 are characterized by various spectroscopies and scanning electronic microscopy. Further, the electrocatalytic HER activity trend of H1 > H2 ≈ H3 is observed in 0.1 M phosphate buffer solution (pH = 7) through different electrochemical measurements, whereas the degradation processes of H1-H3 lead to their electrocatalytic deactivation in the long-term electrolysis as proposed by post operando analysis. Thus, this work is significant to extend the potential application of carbon electrode materials engineered with diiron molecular complexes as heterogeneous HER electrocatalysts for water splitting to hydrogen.

Percutaneous transhepatic cholangioscopy-assisted biliary polypectomy for local palliative treatment of intraductal papillary neoplasm of the bile duct.

BACKGROUND: Intraductal papillary neoplasm of the bile duct (IPNB) is a premalignant biliary-type epithelial neoplasm with intraductal papillary or villous growth. Currently reported local palliative therapeutic modalities, including endoscopic nasobiliary drainage, stenting and biliary curettage, endoscopic biliary polypectomy, percutaneous biliary drainage, laser ablation, argon plasma coagulation, photodynamic therapy, and radiofrequency ablation to relieve mechanical obstruction are limited with weaknesses and disadvantages. We have applied percutaneous transhepatic cholangioscopy (PTCS)-assisted biliary polypectomy (PTCS-BP) technique for the management of IPNB including mucin-hypersecreting cast-like and polypoid type tumors since 2010. AIM: To assess the technical feasibility, efficacy, and safety of PTCS-BP for local palliative treatment of IPNB. METHODS: Patients with mucin-hypersecreting cast-like or polypoid type IPNB and receiving PTCS-BP between September 2010 and December 2019 were included. PTCS-BP was performed by using a half-moon type snare with a soft stainless-steel wire, and the tumor was snared and resected with electrocautery. The primary outcome was its feasibility, indicated by technical success. The secondary outcomes were efficacy, including therapeutic success, curative resection, and clinical success, and safety. RESULTS: Five patients (four with mucin-hypersecreting cast-like type and one with polypoid type IPNB) were included. Low- and high-grade intraepithelial neoplasia (HGIN) and recurrent IPNB with invasive carcinoma were observed in one, two, and two patients, respectively. Repeated cholangitis and/or obstructive jaundice were presented in all four patients with mucin-hypersecreting cast-like type IPNB. All five patients achieved technical success of PTCS-BP. Four patients (three with mucin-hypersecreting cast-like type and one with polypoid type IPNB) obtained therapeutic success; one with mucin-hypersecreting cast-like type tumors in the intrahepatic small bile duct and HGIN had residual tumors. All four patients with mucin-hypersecreting IPNB achieved clinical success. The patient with polypoid type IPNB achieved curative resection. There were no PTCS-BP-related serious adverse events. CONCLUSION: PTCS-BP appears to be feasible, efficacious, and safe for local palliative treatment of both mucin-hypersecreting cast-like and polypoid type IPNB.

Co-occurrence of IPMN and malignant IPNB complicated by a pancreatobiliary fistula: A case report and review of the literature.

BACKGROUND: Intraductal papillary neoplasm of the bile duct (IPNB) is pathologically similar to intraductal papillary mucinous neoplasm (IPMN). However, there are several significant differences between them. The rate of IPMN associated with extrapancreatic malignancies has been reported to range from 10%-40%, and it may occasionally be complicated with the presence of fistulas. IPMN associated with malignant IPNB is extremely rare and only nine cases have been reported in the literature. CASE SUMMARY: We report a 52-year-old man who presented with recurrent cholangitis for nine months. Computed tomography and magnetic resonance cholangiopancreatography showed the common bile duct stricture with dilated pancreatobiliary duct without other abnormal findings. The underlying pathogenesis could not be identified based on the radiologic images. Endoscopic retrograde cholangiopancreatography revealed a pancreatobiliary fistula with dilated main pancreatic duct, biliary stricture with dilated biliary tree, and mucus discharge from the enlarged orifice of the major papilla. The patient underwent SpyGlass cholangiopancreatoscopy due to a suspected mucin-producing biliary neoplasm and indeterminate main pancreatic duct dilatation. Multiple papillary growing neoplasms with vascular images, with the extent of lesions spreading in the biliopancreatic ductal lumens, were identified by SpyGlass. In addition, the presence of a pancreatobiliary fistula was also identified. The patient was diagnosed as having benign IPMN and malignant IPNB with focal invasion by postoperative pathology. Furthermore, varying histological subtypes were present in both IPMN and IPNB. Pylorus-preserving pancreaticoduodenectomy was performed on the patient with excellent results during the 52 month follow-up period. CONCLUSION: We deemed that pancreatography and SpyGlass allowed for an efficient diagnosis of IPMN with pancreatobiliary fistula, whereas the etiology could not be identified by radiologic imaging.