Factors that affect the development of acute hemorrhagic rectal ulcer syndrome and rebleeding.

Objectives: Acute hemorrhagic rectal ulcer syndrome (AHRUS) causes massive bleeding and often recurrent rebleeding from rectal ulcers that form immediately above the dentate line. This study aimed to determine the clinical background and risk factors contributing to rebleeding in patients with AHRUS and the most appropriate method of hemostasis treatment. Methods: This retrospective study included 93 patients diagnosed with AHRUS at Showa University Fujigaoka Hospital, Japan, between April 2009 and November 2018. Information on clinical background factors, endoscopic findings, and hemostasis was obtained from medical records. The relationship with episodes of rebleeding was analyzed by multivariate logistic regression analysis. Results: The median age was 79 years, and 84 patients (90%) had a performance status of grade 2 or higher. The patients had multiple background factors, with a median number of 5 per patient. The background factors could be classified into two major factors: those related to arteriosclerosis and those related to delayed wound healing.In the multivariate analysis, significantly more rebleeding occurred in patients with active bleeding during the initial endoscopy (odds ratio 4.88, 95% confidence interval 1.80-14.46, p = 0.003); significantly less rebleeding occurred in patients for whom hemostasis was first performed by clipping (odds ratio 0.30, 95% confidence interval 0.09-0.88, p = 0.035). Conclusions: In bedridden older individuals with poor general health, multiple combinations of arteriosclerosis-related factors and protracted wound healing factors can induce AHRUS. We strongly recommend performing hemostasis via the clipping method on suspected bleeding points, including active bleeding sites, in AHRUS.

A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones.

A simple and efficient method for α-brominating lactones that affords α-bromolactones under mild conditions using tetraalkylammonium hydroxide (R4N+OH-) as a base was developed. Lactones are ring-opened with Br2 and a substoichiometric amount of PBr3, leading to good yields of the corresponding α-bromocarboxylic acids. Subsequent intramolecular cyclization over 1 h using a two-phase system (H2O/CHCl3) containing R4N+OH- afforded α-bromo lactones in good yields. This method can be applied at the 10 mmol scale using simple operations. α-Bromo-δ-valerolactone, which is extremely reactive and difficult to isolate, could be isolated and stored in a freezer for about one week using the developed method. Optimizing the solvent for environmentally friendly large-scale syntheses revealed that methyl ethyl ketone (MEK) was as effective. In addition, in situ-generated α-bromo-δ-valerolactone was directly converted into a sulfur-substituted functional lactone without difficulty by reacting it with a sulfur nucleophile in one pot without isolation. This new bromination system is expected to facilitate the industrial use of α-bromolactones as important intermediates.

Phosphorus-Recycling Wittig Reaction: Design and Facile Synthesis of a Fluorous Phosphine and Its Reusable Process in the Wittig Reaction.

This study shows that phosphorus sources can be recycled using the appropriate fluorous phosphine in the Wittig reaction. The designed fluorous phosphine, which has an ethylene spacer between its phosphorus atom and the perfluoroalkyl group, was synthesized from air-stable phosphine reagents. The synthesized phosphine can be used for the Wittig reaction process to obtain various alkenes in adequate yields and stereoselectivity. The concomitantly formed fluorous phosphine oxide was extracted from the reaction mixture using a fluorous biphasic system. The fluorous phosphine was regenerated by reducing the fluorous phosphine oxide with diisobutylaluminum hydride. Finally, a series of gram scale phosphorus recycling processes were performed, which included the Wittig reaction, separation, reduction, and reuse.

A resected case of two branch duct-type intraductal papillary mucinous neoplasms showing different clinical courses after a two-year follow-up.

The patient was a 60-year-old man without any particular complaints, but he underwent abdominal computed tomography (CT) and magnetic resonance cholangiopancreatography (MRCP) due to a fatty liver, which revealed two similar cystic lesions regarded as branch duct-type intraductal papillary mucinous neoplasm (BD-IPMN) in the pancreatic body [BD-IPMN (b), 16 mm in size] and tail [BD-IPMN (t), 13 mm in size] without a "high-risk stigmata" or "worrisome features". He subsequently received follow-up by MRCP every 6 months. Two years later, MRCP showed prominent dilation of the main pancreatic duct (MPD) and mural nodule formation within the dilated MPD adjacent to the BD-IPMN (b). Distal pancreatectomy specimens revealed that the BD-IPMN (b) was lined by low-papillary gastric mucinous epithelium with low-to-intermediate-grade dysplasia and involved the MPD, forming a malignant mural nodule showing pancreatobiliary-type IPMN. In contrast, the BD-IPMN (t) was lined by flat, monolayer columnar gastric mucinous epithelium without atypia, which suggested the possibility of a "simple mucinous cyst". A genetic analysis showed KRAS mutation only in BD-IPMN (b). Differences in the histological and genetic findings between two similar BD-IPMNs in the present case may suggest what kinds of examinations should be performed in patients with BD-IPMNs without any worrisome features.