Although attention has focused on the chemopreventive action of retinoic acid (RA) in hepatocarcinogenesis, the functional role of RA in the liver has yet to be clarified. To explore the role of RA in the liver, we developed transgenic mice expressing RA receptor (RAR) ␣-dominant negative form in hepatocytes using albumin promoter and enhancer. At 4 months of age, the RAR ␣-dominant negative form transgenic mice developed microvesicular steatosis and spotty focal necrosis. Mitochondrial ␤-oxidation activity of fatty acids and expression of its related enzymes, including VLCAD, LCAD, and HCD, were down-regulated; on the other hand, peroxisomal ␤-oxidation and its related enzymes, including AOX and BFE, were up-regulated. Expression of cytochrome p4504a10, cytochrome p4504a12, and cytochrome p4504a14 was increased, suggesting that -oxidation of fatty acids in microsomes was accelerated. In addition, formation of H 2 O 2 and 8-hydroxy-2-deoxyguanosine was increased. After 12 months of age, these mice developed hepatocellular carcinoma and adenoma of the liver. The incidence of tumor formation increased with age. Expression of ␤-catenin and cyclin D1 was enhanced and the TCF-4/␤-catenin complex was increased, whereas the RAR ␣/ ␤-catenin complex was decreased. Feeding on a high-RA diet reversed histological and biochemical abnormalities and inhibited the occurrence of liver tumors. These results suggest that hepatic loss of RA function leads to the development of steatohepatitis and liver tumors. In conclusion, RA plays an important role in preventing hepatocarcinogenesis in association with fatty acid metabolism and Wnt signaling. (HEPATOLOGY 2004;40:366-375.)

Background and aims Delayed bleeding after gastric endoscopic submucosal dissection (ESD) in patients receiving anticoagulants remains an unpreventable adverse event. Although direct-acting oral anticoagulants (DOACs) have superior efficacy in preventing thromboembolism, their effects on the occurrence of delayed bleeding remain unclear. This study aimed to elucidate the clinical effect of DOACs on delayed bleeding after gastric ESD. Patients and methods We retrospectively examined 728 patients who received anticoagulants and were treated for gastric neoplasms with ESD in 25 institutions across Japan. Overall, 261 patients received DOACs, including dabigatran (92), rivaroxaban (103), apixaban (45) and edoxaban (21), whereas 467 patients were treated with warfarin. Results Delayed bleeding occurred in 14% of patients taking DOACs, which was not considerably different in patients receiving warfarin (18%). Delayed bleeding rate was significantly lower in patients receiving dabigatran than in those receiving warfarin and lower than that observed for other DOACs. Multivariate analysis showed that age ≥ 65, receiving multiple antithrombotic agents, resection of multiple lesions and lesion size ≥ 30 mm were independent risk factors, and that discontinuation of anticoagulants was associated with a decreased risk of bleeding. In multivariate analysis among patients taking DOACs, dabigatran therapy was associated with a significantly lower risk of delayed bleeding. Conclusions The effects of DOACs on delayed bleeding varied between agents, but dabigatran therapy was associated with the lowest risk of delayed bleeding. Switching oral anticoagulants to dabigatran during the perioperative period could be a reasonable option to reduce the risk of delayed bleeding after gastric ESD.

A rare complication of acute or chronic pancreatitis is the formation of a mediastinal pancreatic pseudocyst (MPP), which is caused by tracking of pancreatic fluids through anatomical openings of the diaphragm into the mediastinum. Herein, we report the imaging characteristics of three cases of this condition. Our results revealed three features in common: (i) the connection between the mediastinum and the pancreatic cystic lesion; (ii) the presence of pleural effusions; and (iii) imaging findings consistent with chronic pancreatitis, such as pancreatic atrophy and calcifications and dilatation and/or stricture of main pancreatic duct (MPD). Serial diameter changes of the MPD and of the adjacent pseudocysts were necessary for the determination of the therapeutic strategy used in each case.

Fecal impaction is the impaired excretion of a large fecal mass, and mild cases are treated by enema and osmotic laxatives. However, treatment-resistant cases need more invasive alternatives. A woman in her 60s presented with abdominal discomfort. Her abdomen was soft and without tenderness. Computed tomography revealed a large mass of feces in her sigmoid colon and no intestinal dilatation proximal to the mass. Endoscopy confirmed a fecal mass occupying the lumen. A glycerin enema, oral administration of polyethylene glycol, and enteral administration of amidotrizoic acid during colonoscopy were ineffective. We maneuvered a guidewire to form a loop at the tip of an endoscope, with which we subdivided the mass for successful removal. The patient's abdominal discomfort disappeared immediately. Endoscopic disimpaction is far less invasive than surgery and should be considered when treating fecal impaction cases, without severe obstructive colitis, which are nonresponsive to conservative treatment.

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