Divalent binding of a bis(adamantyl)-functionalized calix[4]arene to beta-cyclodextrin-based hosts: an experimental and theoretical study on multivalent binding in solution and at self-assembled monolayers

The divalent binding of a bis(adamantyl)-functionalized calix[4]arene (1) to an EDTA-tethered -cyclodextrin (CD) dimer (2) in solution (1.2 × 107 M-1) was 3 orders of magnitude weaker than the binding constant (~1010 M-1) for the interaction of 1 at CD self-assembled monolayers (SAMs) on gold. This difference in binding is rationalized using a theoretical model, which interprets the divalent binding as two consecutive monovalent binding events, i.e., an intermolecular interaction followed by an intramolecular binding event, the latter of which is associated with an effective concentration term accounting for the close proximity of the two interacting species. The methodology presented in the model is applicable to divalent binding both in solution and at SAMs and indicates that the difference in observed binding constants mainly stems from a difference in effective concentration. \ud \u

Endoscopic therapy for type B surgical biliary injury in a patient with short cystic duct

Anatomical variations of the cystic duct are well-defined. The presence of short or absent cystic duct is unusual and represents a co-factor of biliary injury especially during laparoscopic cholecystectomy. Thus, its knowledge is important to avoid ductal injury in hepato-biliary surgery. We experienced the case of a 40-year-old woman with symptomatic cholelitiasis, who underwent to laparoscopic cholecystectomy. At surgery, an accidental bile duct lesion was carried, during Calot’s triangle dissection, due the particular difficulties in dissecting an extremely short cystic duct found at the junction of the common hepatic duct and common bile duct. No vascular anomalies were present. The biliary leakage from the common bile duct was intraoperative identified and subsequentially treated by the endoscopic method. Laparoscopic cholecystectomy with sequential biliary endoprosthesis insertion was completed without conversion to open surgery. The endoscopic stenting was the definitive treatment for the leakage. No evidence of biliary stent complication was observed during the follow-up. This report documents a case of short cystic duct with particular emphasis to the biliary injury risk during the laparoscopic dissection of “unusual” Calot’s triangle, and examines our mini-invasive therapeutic strategies in the management of bile leakage after laparoscopic cholecystectomy

Divalent binding of a (bis)adamantly-functionalized calix[4]arene to b-cyclodextrin-based hosts: An experimental and theoretical study on multivalent binding in solution and at self-assembled monolayers

The divalent binding of a bis(adamantyl)-functionalized calix[4]arene (1) to an EDTA-tethered β- cyclodextrin (CD) dimer (2) in solution (1.2 × 107 M-1) was 3 orders of magnitude weaker than the binding constant ( 1010 M-1) for the interaction of 1 at CD self-assembled monolayers (SAMs) on gold. This difference in binding is rationalized using a theoretical model, which interprets the divalent binding as two consecutive monovalent binding events, i.e., an intermolecular interaction followed by an intramolecular binding event, the latter of which is associated with an effective concentration term accounting for the close proximity of the two interacting species. The methodology presented in the model is applicable to divalent binding both in solution and at SAMs and indicates that the difference in observed binding constants mainly stems from a difference in effective concentration