PubMed · 8477002
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
M Rabaud. 1993. Elastin patches.. https://doi.org/10.1016/0142-9612(93)90126-m
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
The authors examined the modifications of some markers of platelet activation after contact with biomaterials. Glycoprotein GMP-140 (CD62) was evaluated by flow cytometry; beta-thromboglobulin (beta-TG) and thromboxane B2 (TXB2) were determined by radioimmunoassay. Polyethylene terephthalate (PET) induced a remarkable platelet adhesion and a significant increase in beta-TG and TXB2, with no increase in CD62 on the nonadherent platelets. Pyrolytic carbon-coated PET (PC) did not induce platelet adhesion after 15 min of contact, but a significant increase in CD62 was detected. After 30 min a significant increase in platelet adhesion as well as the release of beta-TG and TXB2 were noted. The increase was lower than that observed for uncoated PET, and after 30 min of contact with PC the increase no longer was observed.
Inflammatory mediators such as cytokines produced by white blood cells (WBCs) at the site of implantation are important for the biocompatibility of vascular grafts. The aim of the present study was to demonstrate the tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) release from WBCs incubated with expanded polytetrafluoroethylene (ePTFE) or woven Dacron grafts. In a second series the effects of pentoxifylline (PTX) and iloprost (ILO), both known to inhibit white blood cell function, on this release were determined. Woven Dacron grafts induced significantly higher release of both TNF-alpha and IL-6 compared to ePTFE. TNF-alpha was detectable first after 2 h, whereas IL-6 was seen after 4 h. Maximum values were reached at 6 and 12 h, respectively. The addition of an endotoxin gave more pronounced patterns of cytokine release not influenced by time. Preincubation with both PTX and ILO at final concentrations of 100 and 10 micrograms/mL, respectively, reduced significantly the TNF-alpha release without differences between the two graft materials, whereas the effect on the IL-6 release varied and was graft material-dependent. In conclusion, graft material-dependent induction of TNF-alpha and IL-6 from WBCs was demonstrated. PTX and ILO influenced the cytokine release. It might be suggested that graft material-induced cytokine production could contribute to intimal hyperplasia in vivo. The present findings encourage further studies regarding graft material-induced WBC alterations and the role of pharmacologic agents influencing this function.
Synthesized poly(ester)urea-urethanes with 14C-labeled toluene diisocyanate or 14C-labeled chain extender ethylene diamine were incubated with cholesterol esterase in a phosphate buffer solution at 37 degrees C. A number of biodegradation products, generated at the level of 2.8 micrograms/cm2 of polymer surface area, were isolated from this simulated physiologic system. Individual products were obtained by separation with reversed-phase high-performance liquid chromatography. The two different radiolabels were used to assist in the identification of degradation products from hard- and soft-segment domains. Approximately 20 degradation products were isolated; however, toluene diamine (TDA) was not detected from the chromatographic separation. Two principal products were identified by tandem mass spectrometry. Both products are TDA derivatives (secondary aromatic diamine) substituted with end units of the polyester segment at N and N' positions of TDA. The absence of free TDA suggests that there could be a stabilization of urethane and urea linkages within the toluene diisocyanate (TDI) segments of the polyurethanes. For TDI-synthesized polymers, this finding raises awareness to the potential biological importance of degradation products other than TDA, particularly to their interaction with surrounding cells.