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Biomedical subjects

John J Feng

Publications and source records attributed to John J Feng.

3 recordsLinked to original sources

Early experience with computer-mediated flexible circular stapling technique for upper gastrointestinal anastomosis.

BACKGROUND: Creating the proximal anastomosis in laparoscopic biliopancreatic diversion with duodenal switch (LBPD-DS) and Roux-en-Y gastric bypass (LRYGBP) is a critical step in ensuring the success of the procedures. The aim of this study was to assess the safety and efficiency of performing this anastomosis using a flexible, computerized, circular stapling device. METHOD: We prospectively monitored the use of a newly FDA-approved stapling device (SurgASSIST, Power Medical Intervention) for the construction of the proximal anastomosis by a variety of approaches and reviewed the charts of 10 patients. RESULTS: We successfully constructed 9 out of 10 proximal anastomoses: 2 gastro-jejunostomies and 7 duodeno-ileostomies, without any signs of leakage. In 2 patients, the stapling technique involved a transpyloric instrumental passage; both were complicated by the difficulty to pass either the flexible scope or the anvil through the narrow pyloric lumen. In 5 patients, the anvil was placed directly through a duodenotomy and no technical problems were encountered. The median time for performing the proximal anastomosis was 19 minutes (range 9-55). There were no postoperative complications in any patients. CONCLUSIONS: Stapling using the SurgASSIST was feasible and safe for performing laparoscopic anastomoses in bariatric bypass procedures. A duodenotomy for direct placement of the anvil into the postpyloric region seems to be most feasible for duodenoileostomies, while transoral passage of the anvil can be recommended for gastro-jejunostomies. In its current form, we do not recommend transoral placement of the flexible shaft of the SurgASSIST device. Further clinical trials need to be performed for comparison with existing devices.

Adult↗

Laparoscopic biliopancreatic diversion with duodenal switch.

The biliopancreatic diversion with duodenal switch combines a sleeve gastrectomy with a duodenoileal switch to achieve maximum weight loss. Consistent excess weight loss between 70% to 80% is achieved with acceptable decreased long-term nutritional complications. With a higher entry weight, the super obese patient (body mass index [BMI] >50 kg/m(2)) benefits the greatest from a procedure that produces a higher mean excess weight loss. The laparoscopic approach to this procedure has successfully created a surgical technique with optimum benefit and minimal morbidity, especially in the super obese patient.

Adult↗

Hyperoxia and angiogenesis.

We hypothesized that tissue hyperoxia would enhance and hypoxia inhibit neovascularization in a wound model. Therefore, we used female Swiss-Webster mice to examine the influence of differential oxygen treatment on angiogenesis. One milliliter plugs of Matrigel, a mixture of matrix proteins that supports but does not itself elicit angiogenesis, were injected subcutaneously into the mice. Matrigel was used without additive or with added vascular endothelial growth factor (VEGF) or anti-VEGF antibody. Animals were maintained in hypoxic, normoxic, or one of four hyperoxic environments: hypoxia -- 13 percent oxygen at 1 atmosphere absolute (ATA); normoxia -- 21 percent oxygen at 1 ATA; hyperoxia -- (groups a-d) 100 percent oxygen for 90 minutes twice daily at the following pressures: Group a, 1 ATA; Group b, 2 ATA; Group c, 2.5 ATA; Group d, 3.0 ATA. Subcutaneous oxygen tension was measured in all groups. The Matrigel was removed 7 days after implantation. Sections were graded microscopically for the extent of neovascularization. Angiogenesis was significantly greater in all hyperoxic groups and significantly less in the hypoxic group compared with room air-exposed controls. Anti-VEGF antibody abrogated the angiogenic effect of both VEGF and increased oxygen tension. We conclude that angiogenesis is proportional to ambient pO(2) over a wide range. This confirms the clinical impression that angiogenesis requires oxygen. Intermittent oxygen exposure can satisfy the need for oxygen in ischemic tissue.

Animals↗