June 19, 2017 | Autor: Robert Stein | Categoria: Urology, Robotic Surgery, Clinical Sciences
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Vol. 181, No. 4, Supplement, Monday, April 27, 2009

1198 OXYGEN PRODUCING MATERIALS FOR ENHANCING CELL SURVIVAL Catherine Ward*, Se Heang Oh, Anthony Atala, James J Yoo, Benjamin Harrison, Winston Salem, NC INTRODUCTION AND OBJECTIVES: Many times engineered tissue lacks a sufficient vascular supply to provide cells the needed oxygen to survive. This has been a critical limiting factor for developing functional tissues for human applications. We have developed a novel method to prolong cell survival until host neovascularization is achieved using in situ generation of oxygen. In this study we investigated the possibility of incorporating oxygen generating biomaterials into tissue engineered constructs to provide a sustained oxygen release over an extended period of time. We examined whether oxygen generating biomaterials are able to maintain cell viability while also maintaining structural integrity of a three-dimensional construct. METHODS: Poly(co-lactic-co-glycolic acid) PLGA was dissolved in dimethyl sulfoxide (DMSO, Aldrich). 5 wt% calcium peroxide (CPO) was added to the mixture and mixed well. The CPO suspended PLGA solution was then mixed with paraffin particles and then transferred to a silicone mold to fabricate scaffolds. To measure the amount of oxygen produced, the scaffolds were placed into media that had been equilibrated to 1% oxygen. Oxygen concentrations were measured using a blood gas analyzer and reported as a percentage of increase compared to average oxygen levels in normal media. To test the cell compatibility, 3T3 cells were seeded onto the scaffold and evaluated each day using an MTS assay. RESULTS: The scaffolds showed an overall average increase in oxygen levels over a ten day period. To evaluate the effect of CPO, cellseeded PLGA and PLGA/CPO scaffolds were cultured under normoxic conditions (21% O2, 5% CO2) for 3 days and the viable cell numbers in each scaffold were estimated using an MTS assay. The oxygen generating scaffolds showed at least equivalent cell numbers after three days compared to PLGA only scaffolds. At a concentration of 5 wt% CPO, no statistically significant decrease (p>0.05) in cell number was observed. CONCLUSIONS: Oxygen generating biomaterials produced a steady increase in oxygen concentration. These scaffolds are able to provide an adequate environment for cell survival and growth in hypoxic environments. The use of oxygen generating biomaterials may allow for increased cell survivability while neovascularization is being established after implantation. Source of Funding: Departmental

1199 INVESTIGATIONS ON THE BIOCOMPATIBILITY OF A NEW COLLAGEN-BASED MATRIX FOR HUMAN UROTHELIAL CELLS Gerhard Feil*, Sabine Maurer, Lothar Just, Jutta Krug, Konrad Kohler, Arnulf Stenzl, Karl-Dietrich Sievert, Tuebingen, Germany INTRODUCTION AND OBJECTIVES: In vitro engineering of lower urinary tract tissue equivalents suitable for reconstructive surgery might require biomaterials as cell carriers. Matrices have to be biocompatible, induce tissue regeneration, and must be subject to rapid degradation in vivo. The aim of the pilot study was to prove adherence, viability, and growth pattern of human urothelial cells (HUCs) seeded on a new factory-made bovine collagen I-based matrix. METHODS: Ureter tissue specimens were obtained from adult patients undergoing open tumor surgery according to the ethics committee approval. HUCs were isolated and labelled with the fluorescent cell linker PKH26, seeded onto the collagen matrix, and cultivated in serum-free medium. Cell adherence was indirectly ascertained by counting nonadherent cells in the culture supernatant. Growth behaviour was studied by phase contrast microscopy and cryosections of the populated matrix. Viability of HUCs seeded onto the collagen matrix was analysed with the WST-1 assay. RESULTS: HUCs grown on the collagen matrix were as homogeneously spread as HUCs seeded onto standard plastic surface. At day 1 after seeding the fraction of non-adherent HUCs was slightly


increased (2.2%) compared to the controls (0.3%), whereas at day 3 both groups revealed similar rates (0.4% and 0.3%, respectively). Viability of HUCs growing on the matrix revealed 111% of the control group at day 3. The cell-matrix constructs could be easily detached from the culture dish and were manageable with surgical instruments. CONCLUSIONS: The data demonstrate a good in vitro biocompatibility of the new bovine collagen I-based matrix. We conclude that the matrix might be well suitable for construction of urothelial cellmatrix implants for reconstructive ureteral and urethral surgery. Further experiments with urothelial multilayers grown on the matrix will be performed in vitro as well as in vivo. Source of Funding: None

Technology & Instruments: Robotics/Laparoscopy (IV) Moderated Poster 40 Monday, April 27, 2009

3:30 pm - 5:30 pm

1200 VIDEO ENDOSCOPIC INGUINAL LYMPHADENECTOMY (VEIL): OUR INITIAL EXPERIENCE Yuvaraja B Thyavihally*, Hemant B Tongaonkar, Abhijit Bapat, Mumbai, India INTRODUCTION AND OBJECTIVES: Inguinal lymph node dissection in carcinoma of penis is associated with significant wound related complications like flap necrosis, infection etc. We present our initial experience with video endoscopic inguinal lymphadenectomy (VEIL), minimally invasive approach to avoid complications of open groin node dissection (GND). METHODS: From October 2007 to October 2008, 16 patients were operated for bilateral GND, one side standard GND and other side VEIL. VEIL was done for clinically N0 groin in 13 cases and for N1 in 3 cases (Right side in 4 and left in 12 patients). Selection criteria were absence of infective nodes, < 3cm nodes, non obese patient and N0 groin in high risk primary carcinoma of penis. Patient was positioned in low lithotomy with boot shaped leggings. Transverse incision up to the level of fascialata and finger dissection is done separating the flap from fascialata. Two working ports are placed under vision. Entire tissue along with fascialata is separated from muscle; sapheno-femoral junction is divided. RESULTS: Mean operative time for VEIL was slightly more with 150 minutes and for open GND was 110 (p=0.02). Numbers of Lymph nodes retrieved by VEIL were 8-16 nodes which were comparable to open GND (10-16 nodes). Flap necrosis occurred in 7 patients (one mild, two moderate and two severe) in open GND side and one in VEIL side. Six and 3 patients each in open and VEIL side had lymphocele which required repeated aspiration. With short follow up of 3-12 months, none of the patients had relapse. CONCLUSIONS: In selected cases of high risk carcinoma penis with negative groin or lymph node metastasis
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