Effect of fibronectin on the binding of antithrombin III to immobilized heparin

An objective of this research is to verify the mechanism of anticoagulant activity of surface-immobilized heparin in the presence of plasma proteins. The competition and binding interaction between immobilized heparin and antithrombin III (ATIII)/thrombin have been described in vitro. However, the strong ionic character of heparin leads to its specific and nonspecific binding with many other plasma proteins. Most notably, fibronectin contains six active binding sites for heparin which may interfere with the subsequent binding of heparin with ATIII or thrombin. \ud Heparin was covalently immobilized through polyethylene oxide (PEO) hydrophilic spacer groups onto a model surface synthesized by random copolymerization of styrene and p-aminostyrene. The binding interaction of immobilized heparin with ATIII was then determined in the presence of different fibronectin concentrations. The binding interaction was studied by first binding immobilized heparin with ATIII, followed by the introduction of fibronectin; heparin binding with fibronectin, followed by incubation with ATIII, and simultaneous incubation of surface immobilized heparin with ATIII and fibronectin. The extent of ATIII binding to heparin in each experiment was assayed using a chromogenic substrate for ATIII, S-2238. \ud The results of this study demonstrate that the displacement of ATIII from immobilized heparin was proportional to the fibronectin concentration, and was reversible. Furthermore, the binding sequence did not play a role in the final concentration of ATIII bound to immobilized heparin

Cultivating Future Leaders: Faculty Leadership Seminar at Clermont College

Like many universities, ours faced the challenge of needing to cultivate future department chairs and other academic leaders. Current department chairs developed a leadership seminar, a year-long series of workshops and roundtables discussions for faculty from every department. The seminar alternates with a broader-based, informal leadership discussion series

Heparin release from thermosensitive hydrogels

Thermosensitive hydrogels (TSH) were synthesized and investigated as heparin releasing polymers for the prevention of surface induced thrombosis. TSH were synthesized with N-isopropyl acrylamide (NiPAAm) copolymerized with butyl methacrylate (BMA) (hydrophobic) or acrylic acid (AAc) (hydrophilic) comonomers. The incorporation of hydrophobic and hydrophilic comonomers strongly influences the swelling/shrinking behavior of TSH. Upon deswelling, gels containing the hydrophobic comonomer formed a skin-type layer, which acted as a rate controlling membrane, while the hydrophilic comonomer greatly increased gel swelling, relative to NiPAAm. Equilibrium swelling in isotonic PBS and deswelling kinetics of the synthesized gels were examined at various temperatures. The loading of heparin into the different gels was studied as a function of temperature, solution concentration, and gel composition. The release kinetics of heparin was found to be influenced by gel composition and loading temperature; the release correlated with the gel deswelling kinetics. In the case of Ni-PAAm/BMA gel, the release profile of heparin was affected by temperature dependent properties of the skin-type diffusional barrier formed on the gel surface

A simple, novel method for preparing an effective water oxidation catalyst

A novel oxygen catalyst is prepared via the photodeposition of ruthnium (IV) oxide on a titania photocatalyst derived from a perruthenate precursor