title: Plasma recalcification as a measure of contact phase activation and heparinization efficacy after contact with biomaterials.
abstract: The rate of plasma clotting was measured in order to investigate two different processes. In both cases normal, pooled platelet-poor plasma was used as a substrate for measurement of clotting. The intrinsic coagulation pathway was studied by bringing a variety of biomaterials into contact with a plasma aliquot and observing the rate of clotting diminish by virtue of factor XII activation. The efficacy of heparinization was investigated by measuring the increase in clotting time of a plasma aliquot during biomaterial contact. In both cases, clotting time was measured turbidometrically. Marked differences in intrinsic pathway activation were observed between a variety of materials. There were clear differences between the materials and the negative and positive controls. The assay showed that heparinized materials could be distinguished from non-heparinized materials and a non-activated plasma control.
authors.affiliation: Department of Clinical Engineering, University of Liverpool, UK.
authors.forename: N P
authors.initials: NP
authors.lastname: Rhodes
authors.forename: D F
authors.initials: DF
authors.lastname: Williams
mesh_terms: D001672:Biocompatible Materials / Q000494:pharmacology*; D001777:Blood Coagulation / Q000187:drug effects*; D001780:Blood Coagulation Tests; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D008297:Male; D009391:Nephelometry and Turbidimetry; D010314:Partial Thromboplastin Time
chemical_list: D001672:Biocompatible Materials; D006493:Heparin