Active interfacial modifier: stabilization mechanism of water in silicone oil emulsions by peptide-silicone hybrid polymers.

We have developed hybrid amphiphilic polymers consisting of a silicone backbone modified with hydrocarbon chains and hydrolyzed silk peptides. These polymers are molecularly soluble neither in water nor in most of organic solvent, but are attractive with these solvents. We assume that this property enables the polymers to form "an independent third phase" between immiscible two liquid phases and stabilize the emulsion system, based on a fundamentally distinguishable mechanism from the approach by conventional surfactants. We have named these amphiphilic polymers "active interfacial modifier (AIM)" and studied physicochemical properties of AIM-stabilized water-in-silicon oil emulsions. The addition of AIM to a mixture of water and decamethylcyclopentasiloxane (D(5)) has achieved preparation of stable W/O emulsions (droplet size = ca. 1 microm) in a wide range of the three components, even under relatively gentle vortex mixing. Interestingly, the prepared W/O emulsions are found to be nearly genuine or quasi Newtonian fluid with low viscosity when water content is in the range from 0 to 36 wt % for the fixed weight ratio of AIM/D(5) = 6/4. This is a good piece of evidence that AIM forms the independent third phase, where the Newtonian shear occurs at the D(5)/AIM interface. The presence of AIM as third phase has also been confirmed by fluorescence probe method with confocal laser scanning microscopy. As such, AIM can activate interfaces by the least amount to cover interfaces as an independent third phase, and hence, this provides a new concept achieving a precise control of interfacial properties.

Domino Reconstruction of the Portal Vein Using the External Iliac Vein and an ePTFE Graft in Pancreatic Surgery.

BACKGROUND: In the portal vein resection of long distance, an interposition by autologous vein is mandatory. External iliac vein (EIV) has been used, but harvesting the EIV is associated with severe venous congestion of the affected lower extremity. We have reconstructed the EIV using a ringed expanded polytetrafluoroethylene (ePTFE) graft. METHODS: Thirteen patients underwent this surgery. The right EIV was used for reconstructing the portal vein, and the retrieved portion of EIV was interposed by the ePTFE graft. We evaluated size and length of the graft, graft patency, girth of thigh, time for reconstruction of EIV, and graft infection. RESULTS: ePTFE grafts of 8 or 10 mm in diameter were used. The length of ePTFE graft used was 4.4 ± 0.5 cm. Graft patency was kept in 76.9% patients. Graft obstruction was encountered in three patients, and the girth of right thigh increased by about 10 cm. Time for reconstruction of EIV was 29.5 ± 6.8 min. Graft infection did not occur in any patients. CONCLUSIONS: Reconstruction of the EIV using a ringed ePTFE graft seems to be a feasible option for preventing the swelling of the affected lower extremity after procurement of EIV for repairing the portal vein.

New techniques: combined endoscopic injection sclerotherapy and ligation for acute bleeding from gastric varices.

BACKGROUND/AIMS: Combined endoscopic injection sclerotherapy and endoscopic variceal ligation was used for the treatment of acute bleeding from gastric varices. METHODOLOGY: Between July 1995 and August 1998, three cirrhotic patients with acute bleeding from gastric varices were treated. Endoscopic variceal ligation of the puncture point and bleeding point was performed simultaneously. RESULTS: Acute bleeding from the gastric varices was successfully stopped in all cases. CONCLUSIONS: Combined endoscopic injection sclerotherapy and endoscopic variceal ligation can be used to stop bleeding and prevent rebleeding from gastric varices.