Molecular weight-dependent contact activation of plasma induced by soluble polystyrene and dextran derivatives

Abstract

The surface dependent contact activation of human plasma was studied as a function of the molecular weight of several synthetic macromolecular and watersoluble derivatives: polystyrene sulphonates, dextran methyl - benzylamide sulphonate/carboxylates as well as dextran sulphates as reference materials. Extent of the contact activation was determined by the amidolytic activities generated from cold activation of plasma in the presence of dilutions of the polymers for varying incubation times. The activating properties of the materials have been rationalied by means of a parameter calculated from the shapes of the amidolytic rates vs. incubation time variations. It was found that all the studied polymers behave similarly : contact stimulating properties begin to increase sharply passed a molecular weight of 25,000 and thereafter gradually reach a limiting plateau for Mw = 100,000. Activating capacities estimated for these limiting values have been expressed in term of specific capacities unrelated to Mw effects. These parameters were also compared to that of standard heparin estimated in the same conditions.