treated ischemic limbs. Similar findings were noted at 4 weeks postisch- emia. Furthermore, IRI-induced apoptosis was significantly decreased in HS- treated ischemic limbs (58%–90%) versus ischemic controls. CONCLUSIONS: Our results demonstrate that HS- completely prevents muscle cell injury in both in vitro and in vivo models of IRI. These data validate use of this molecule as a cytoprotectant with significant therapeutic potential in FTT and other conditions asso- ciated with IRI. Waveform optimization of the Vacuum Assisted Closure device Douglas L Helm MD, Pouya Dastouri MD, Saja Scherer MD, Giorgio Pietramaggiori MD, Dennis P Orgill MD, PhD, FACS Brigham and Women’s Hospital, Boston, MA INTRODUCTION: Using a murine model, we have demonstrated that the Vacuum Assisted Closure device (VAC, Kinetics Concepts Inc) transduces micromechanical forces to a wound bed via a sponge under continuous suction causing wound proliferation and angio- genesis. Although widely used in a variety of wounds, including complex diabetic wounds, the VAC is largely used to deliver contin- uous suction without variation or pattern to the applied force. In this study, we evaluated whether modulating the waveform changes gran- ulation tissue formation, cellular proliferation, or angiogenesis. METHODS: Full-thickness wounds were made in male diabetic mice (C57BL/KsJ-Lepr db) and treated with the VAC device with 6 different modalities: square waveforms of 125 mm Hg suction for 2 minutes alternating with 50 mm Hg suction for 2 minutes, 5 min- utes, or 10 minutes; sinusoidal waveform with 3.5 minutes at 125 mm Hg followed by 3.5 minutes of 50 mm Hg suction; continuous suction at 125 mm Hg or non-treated with an occlusive dressing alone. Eight mice per group were wounded and following 7 days of treatment wounds were evaluated by quantifying the depth of gran- ulation tissue, new cell proliferation using the nuclear marker ki67, and angiogenesis using the endothelial cell marker CD31. RESULTS: The continuous and sinusoidal waveform treatment in- duced the highest cellular proliferation rates, angiogenesis, and gran- ulation tissue depth compared with controls. Decreasing square waveform frequency had a trend toward increased cell proliferation, angiogenesis, and granulation tissue depth. CONCLUSIONS: Waveform modulation appears to have a minor effect on granulation tissue formation, angiogenesis, and prolifera- tion in our diabetic mouse model. Obesity impairs wound healing via a vasculogenic mechanism Ida JanelleWagner MD, Robert J Allen MD, Phuong D Nguyen MD, Edward H Davidson MA, MBBS, John PTutela MD, Orlando Canizares MD, Pierre B Saadeh MD, FACS, Stephen M Warren MD, FACS New York University, New York, NY INTRODUCTION: Obesity is an epidemic. Since bone marrow– derived endothelial progenitor cells (EPCs) are responsible for 35% of new blood vessel formation in healing wounds, we hypothesize that impaired wound healing in nondiabetic obesity is due to EPC dysfunction. METHODS: Peripheral blood was obtained from nondiabetic obese patients (BMI  30, n = 10), and nonobese controls (BMI  30, n = 10). EPCs were isolated, and in vitro adhesion, migration, and proliferation assays were performed. In vivo, we created 6-mm stented wounds on nondiabetic, obese mice (TallyHo/JngJ, n = 5) and nonobese controls (C57Bl/6, n = 5). Wound healing was as- sessed photometrically on days 0, 7, 10, and 14. Time to closure was defined as the time to complete re-epithelialization of the wound bed. Wound area was calculated as a percentage of the original wound. RESULTS: EPCs from obese humans (EPC-ob) had impaired ad- hesion to collagen-coated slides compared with nonobese human EPCs (EPC-n) (92  20 cells per LPF vs 137  65 cells per LPF; p=0.05). EPC-ob had impaired migration compared with EPC-n (117  21 cells per LPF vs 393  6 cells per LPF; p=0.02). EPC-ob had impaired proliferation compared with EPC-n (179  15 RFU vs 305  63 RFU; p=.0001). Obese mice wound healing was delayed by 42%. Wounds of obese mice demonstrated decreased new blood vessel formation (3  2 per HPF vs 9  2 per HPF). CONCLUSIONS: Our data implicate EPC dysfunction as a possible mechanism behind impaired wound healing in obesity. Ongoing experiments are exploring therapeutic strategies for wound healing in obesity. Early detection of complete venous occlusion in a rodent and swine pedicle flap model using modulated imaging, a new novel multispectral imaging technique Michael R Pharaon MD, Thomas Scholz MD, Scott Bogdanoff, David Cuccia PhD, Anthony J Durkin PhD, David B Hoyt MD, FACS, Gregory RD Evans MD, FACS University of California, Irvine, Orange, CA INTRODUCTION: Venous occlusion after a tissue transfer flap is a devastating complication that can lead to complete flap loss. We used a new noncontact, noninvasive imaging device developed at the Beckman Laser Institute to monitor flaps. METHODS: In this study, bilateral pedicle groin flaps based on the inferior epigastric vessels were prepared in Wistar Rats (400–500 g), and Yorkshire Pigs (25–30 kg). The flaps were imaged at baseline for 10 minutes, followed by selective complete venous occlusion in the experimental flap and imaging for 55 minutes. The contralateral flap served as a control. The results were analyzed using a Wilcoxon signed rank t test, as well as a 2-way ANOVA with Bonferroni post- test to analyze the differences between the control and experimental flaps over the entire time course. RESULTS: Baseline measurements showed stable results for oxy- genated hemoglobin, deoxygenated hemoglobin, total hemoglobin, and tissue saturation. There were no statistical differences for each of the above parameters between the control and experimental flaps S77 Vol. 209, No. 3S, September 2009 Surgical Forum Abstracts