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Antithrombin coatings

Knitted polyester grafts (6mm inner diameter) with covalently bound rHir were subjected to simulated physiologic flow conditions to determine the stability of the antithrombin coating (41) (Figure 3). Both constant flow of shear rate 300 s, and pulsatile flow of maximum shear rate 780s-1 were used for a seven-day period. The loss was moderate in both cases (approximately 50% of the rHir and 20% of the albumin). The ability of these modified surfaces to remove thrombin from the perfusion stream was comparable with that found in the parallel static experiments 3 NIHU of thrombin/cm was bound by the rHir grafts, compared to 0.6 NIHU of thrombin/cm for albumin-coated grafts. Similarly, the total amount of thrombin inactivated over the seven days was 125 NIHU for surface boimd rHir versus 10 NIHU for surface bound albumin. [Pg.129]

At present, the binary water-soluble preparation of heparin and proteolytic enzymes is being applied for the treatment of thromboses. For instance, injection into the bloodstream of heparin-plasmin complex or a heparin-plasmin-streptokinase preparation leads to the total dissolution of the thrombus, while if introduced separately, heparin and streptokinase do not display the lytic action at all, and plasmin, alone or together with streptokinase, dissolves the thrombus only partially 132>. The treatment of acute thrombophlebitis with trypsin resulted in a full dissolution of the thrombus and in an increase of antithrombin III in the blood 133). Administration of trypsin together with heparin has an effect similar in efficiency to the action of the heparin-plasmin complex 134>. The use of a mix of heparin and urokinase for improving tbrom-boresistance of polymeric materials was also described 13S). These substances were immobilized by preliminary coating of the surface of a polymer with a graphite layer and subsequent adsorption of heparin and the enzyme. [Pg.127]

Mechanism and effects Regular heparin binds to and activates endogenous antithrombin 111 (ATlIl). The heparin-ATIll complex combines with and inactivates thrombin (activated factor 11) and several other factors, especially factor X. In the presence of heparin, antithrombin III inhibits the coagulation factors approximately 1000-fold faster than in its absence. Low doses of heparin also coat the endothelial walls of vessels and reduce the activation of clotting elements by these cells. Because it acts on preformed blood components, heparin is also active in vitro—almost instantaneously. The action of heparin is monitored with the activated partial thromboplastin time laboratory test (aPTT or PTT). [Pg.306]

PEG-modifiedPU with antithrombin-heparin coating Multistep modification Different PEG intermediate layers ATH efficacy Static, in vitro Human plasma Good cell proliferation on ATH-PEG-OH-PU, antihrombin binding superior to fibrinogen [88]... [Pg.303]

Du YJ, Klement P, Berry LR, Tressel P, Chan AKC. In vivo rabbit acute model tests of polyurethane catheters coated with a novel antithrombin-heparin covalent complex. Thromb Haemostasis 2005 94(2) 366-72. [Pg.317]


See other pages where Antithrombin coatings is mentioned: [Pg.66]    [Pg.66]    [Pg.145]    [Pg.262]    [Pg.43]    [Pg.815]    [Pg.221]    [Pg.249]    [Pg.159]    [Pg.576]    [Pg.649]    [Pg.686]    [Pg.300]    [Pg.303]    [Pg.324]    [Pg.580]    [Pg.287]    [Pg.300]    [Pg.303]    [Pg.324]    [Pg.580]    [Pg.492]    [Pg.506]   
See also in sourсe #XX -- [ Pg.66 ]




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