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Background Pancreatic juice reflux to the common bile duct and gallbladder is observed in the pancreaticobiliary maljunction (PBM), and various pathological conditions occur in the biliary tract. However, the mechanism of pancreatic juice reflux has not been discussed yet. This study aimed to investigate the mechanism of this phenomenon from the perspective of the fluid dynamics theory. Methods A fluid dynamics model of PBM without biliary dilatation having gallbladder function and of the pressure of sphincter of Oddi was developed. Water (as bile juice and pancreatic juice) was flowed to these models with a flow rate similar to that in humans. Pancreatic and bile juice flow and bile duct pressure were observed in three phases of gallbladder function. Moreover, the same experiment was performed in the PBM without biliary dilatation model without gallbladder. Results Pancreatic juice reflux could be observed when the gallbladder was passively expanded with the pressure in the bile duct lower than that in the sphincter of Oddi. However, pancreatic juice reflux was not observed in the model without gallbladder. Conclusions Gallbladder function may be strongly involved in pancreatic juice reflux in PBM without biliary dilatation. Cholecystectomy may be able to stop the reflux of pancreatic juice.

The enantioselective hydrolysis of p-nitrophenyl esters of alpha-amino acids (Phe, Leu, Ala) was accomplished in micelles formed with the surfactants bearing one or two sugar-amide headgroups. The effect of structural variations in such sugar-amide surfactants on the rates and enantioselectivity (kD/kL) for hydrolysis of p-nitrophenyl esters of D- and L-phenylalanine hydrogen bromides (D- and L-PheONp) was studied. Both the hydrolysis rate of D-PheONp and the enantioselectivity increased with an increase in the alkyl chain length as well as an increase in the number of the alkyl chains in the maltobionamide-type surfactants. Enantioselectivity also increased with an increase in the sugar chain length from bisgluconamide to bismaltobionamide (by one glucose unit per each sugar chain) in the double-sugar-chain surfactants, but enantioselectivity was no longer influenced by a further increase to bismaltotrionamide. The stereochemistry of the linkage between the sugar units in the sugar chain remarkably affected the enantioselectivity: the maltobionamide-type surfactant, in which the two sugar units are connected by an alpha-1,4-glucosidic linkage, showed high enantioselectivity (kD/kL = 5.5), whereas the surfactant bearing cellobionamide headgroups (beta-1,4-glucosidic linkage) showed no enantioselectivity. Similar trends were observed when p-nitrophenyl esters of D- and L-leucine hydrogen bromides were used as substrates. On the other hand, the rates and enantioselectivity for hydrolysis of p-nitrophenyl esters of D- and L-alanine hydrogen bromides were not so largely affected by the structural variations in the sugar-amide surfactants. Additionally, the effects of the surfactant concentration and the reaction temperature on the rates and enantioselectivity for the hydrolysis of D- and L-PheONp were examined.

Background Biliary atresia in very low birth weight (VLBW) and extremely low birth weight (ELBW) infants is rarely reported, and the optimal timing of Kasai portoenterostomy (KPE) in these cases remains unclear. Case presentation We report a case of biliary atresia in a preterm female infant of 24 weeks of gestation who weighed 824 g. She underwent exploratory laparotomy and intraoperative cholangiography at 58 days of age (weight, 1336 g). Despite the diagnosis of biliary atresia with a type I cyst, we could only perform gallbladder drainage at that time due to the unstable intraoperative condition. While we waited for her body weight to increase, KPE was performed at 122 days of age (corrected age: 16 days), when the patient weighed 2296 g. Although she initially became jaundice-free, her liver function deteriorated due to cholangitis, and she developed decompensated cholestatic liver cirrhosis. Living donor liver transplantation was successfully performed at 117 days after KPE, and the postoperative course was uneventful. The timing of KPE is difficult to determine and a review of the relevant literature revealed that a poor prognosis in VLBW and ELBW infants with BA. Conclusions Early KPE and careful postoperative follow-up, including liver transplantation is important for the improvement of outcomes.

Background: Intraperitoneal arterial hemorrhage without trauma is extremely rare. We report two infant cases of intraperitoneal arterial hemorrhage due to intestinal duplication. Case presentation: In case 1, a 2-month-old girl experienced sudden intraperitoneal hemorrhage from the middle colic artery with no apparent trauma. Hemostasis was achieved with suturing of the hemorrhage point, but the cause of hemorrhage was still unknown. Computed tomography after the first operation revealed a duodenal duplication cyst and a pseudopancreatic cyst. Percutaneous drainage of the pseudopancreatic cyst was performed, and the contents had high pancreatic amylase. As the size of the duodenal duplication cyst also decreased with this drainage, we suspected that the duodenal duplication cyst was connected to the pseudopancreatic cyst and the arterial hemorrhage. We hypothesized that the pancreatic juice inside the duplication cyst leaked into the intraperitoneal cavity and caused rupture of the arterial wall. Therefore, marsupialization of the duodenal duplication was performed to evacuate the pancreatic juice contained in the cyst toward the native duodenum. The postoperative course was uneventful. In case 2, a 6-month-old boy experienced sudden intraperitoneal hemorrhage without trauma. The hemorrhage site was identified as the ileocecal artery, and hemostasis was achieved with sutures. Tissue near the hemorrhage point was biopsied, because the cause of arterial wall rupture was still unknown. The biopsied tissue was found to be intestinal mucosa. The patient had recurrent abdominal pain after the first operation, and computed tomography showed a duplication cyst located near the hemorrhage point. Therefore, we resected the intestinal duplication. Pathology results showed that the intestinal duplication contained intestinal mucosa, ectopic gastric mucosa, and pancreatic tissue. The postoperative course was uneventful. Conclusion: Intraperitoneal arterial hemorrhage without trauma is an extremely rare condition, and identifying its cause is difficult. To our knowledge, this is the first report of intraperitoneal arterial hemorrhage due to intestinal duplication. In cases of unexplained intraperitoneal arterial hemorrhage in infants, intestinal duplication near the hemorrhage point should be suspected.