Eric Volckmann

Transepithelial Transport of PAMAM Dendrimers Across Isolated Human Intestinal Tissue

Poly(amido amine) (PAMAM) dendrimers have shown transepithelial transport across intestinal epithelial barrier in rats and across Caco-2 cell monolayers. Caco-2 models innately lack mucous barriers, and rat isolated intestinal tissue has been shown to overestimate human permeability. This study is the first report of transport of PAMAM dendrimers across isolated human intestinal epithelium. It was observed that FITC labeled G4-NH2 and G3.5-COOH PAMAM dendrimers at 1 mM concentration do not have a statistically higher permeability compared to free FITC controls in isolated human jejunum and colonic tissues. Mannitol permeability was increased at 10 mM concentrations of G3.5-COOH and G4-NH2 dendrimers. Significant histological changes in human colonic and jejunal tissues were observed at G3.5-COOH and G4-NH2 concentrations of 10 mM implying that dose limiting toxicity may occur at similar concentrations in vivo. The permeability through human isolated intestinal tissue in this study was compared to previous rat and Caco-2 permeability data. This study implicates that PAMAM dendrimer oral drug delivery may be feasible, but it may be limited to highly potent drugs.

Dual Ring Wound Protector Reduces Circular Stapler Related Surgical Site Infections in Patients Undergoing Laparoscopic Roux-En-Y Gastric Bypass

BackgroundWhile there are various techniques to create the gastrojejunostomy during a laparoscopic Roux-en-Y gastric bypass (LRYGB), many surgeons prefer using a circular stapler. One drawback of this method, however, is the higher incidence of surgical site infections (SSIs). To investigate the effect of a dual ring wound protector on SSIs during LRYGB.MethodsIn April 2016, our bariatric surgical group implemented an intervention whereby a dual ring wound protector in conjunction with a conical EEA stapler introducer was used when creating the gastrojejunostomy. SSIs from pre- and post-intervention were compared using Fisher’s exact test. Only LRYGBs performed with a circular stapler were included in our analysis. Student’s t test and χ2 were used to compare pre- and post-intervention groups with respect to demographics and co-morbidities.ResultsBetween April 2015 and January 31st, 2017, our surgeons performed 158 LRYGBs using a circular stapler for the gastrojejunostomy. There were 84 patients (53%) in the pre-intervention group and 74 (47%) in the post-intervention group. The pre- and post-intervention groups were not statistically different. The SSI rate for the pre-intervention group was 9.5% while the SSI rate was 1.35% in the post-intervention group (p = 0.0371). The use of a dual ring wound protector for LRYGBs with circular stapled gastrojejunostomy was associated with an 86% relative risk reduction in SSIs.ConclusionUsing a dual ring wound protector in conjunction with a conical EEA introducer for LRYGBs with circular stapled gastrojejunostomy significantly decreased SSIs.

Coding for Laparoscopic Surgery

Laparoscopic approaches to conventional surgery are a fundamental technique in every general surgeon’s armamentarium. While the origins of laparoscopy dates back more than a century [1], the technique, as practiced today, is relatively new. That said, once introduced to the United States, the development of laparoscopy grew exponentially.