Improvements in GORE-TEX® vascular graft performance by Carmeda® bioactive surface heparin immobilization

AbstractObjectives: a performance improvement in small-diameter bypass grafts remains a clinical objective. The purpose of the present investigation was to evaluate the potential of enhancing the thromboresistance of ePTFE grafts using a bioactive heparinized graft luminal surface in a canine model. Material and Methods: this study investigated the utility of heparin immobilization onto expanded polytetrafluoroethylene using Carmeda® BioActive Surface technology (CBAS-ePTFE) as a means of improving vascular graft thromboresistance. Graft luminal surfaces were covered uniformly with the stably bound, end-point immobilized heparin. Results: acute canine (5 greyhounds) interposition experiments comparing CBAS-ePTFE grafts to control ePTFE grafts showed that CBAS-ePTFE grafts remained patent and had significantly greater thrombus-free luminal surface (p < 50.05). In a chronic canine (16 greyhounds) interposition experiment, significantly improved patency (p < 50.05) was observed with CBAS-ePTFE grafts compared to controls. Long-term in vivo heparin bioactivity was demonstrated on CBAS-ePTFE grafts explanted between 1 and 12 weeks. On all CBAS-ePTFE grafts, heparin activity levels ranged from 15-25 pmol/cm2 and did not differ significantly (p > 40.05). Discussion: these results support the conclusion that a stable, CBAS-ePTFE surface provides improved thromboresistance and improved patency in canine interposition models. Maintenance of heparin catalytic activity on the graft surface in vivo likely contributes to this outcome and holds promise for the utility of this graft surface for clinical applications.Eur J Vasc Endovasc Surg 25, 432-437 (2003

Morfologia e desenvolvimento do núcleo vitelínico do lambari Astyanax bimaculatus (Linnaeus, 1758) (Osteichthyes, Characidae)

<abstract language="eng">A morphological study of the yolk nucleus in previtellogenic oocytes from A. bimacularus has been carried out. Six phases of development were described from its formation closed to the oocyte nucleus to its dispersion in the periferic ooplasm. Histochemical techniques indicate proteins, lipids and RNA in the yolk nucleus of A. bimaculatus, but there are no carbohydrate in this structure. The origin and functional activity of the teleost yolk nucleus are discussed