Assessment of material-induced procoagulant activity by a modified Russell viper venom coagulation time test
✍ Scribed by Gemmell, Cynthia H.
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 158 KB
- Volume
- 42
- Category
- Article
- ISSN
- 0021-9304
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✦ Synopsis
Platelet activation is an inevitable consequence of blood-material interactions. The ability of those activated platelets and platelet-derived microparticles to enhance coagulation reactions leading to thrombin/fibrin formation has not been well studied despite its potential significance. Activated platelets and platelet-derived microparticles are known to dramatically enhance the catalytic efficiencies of the tenase and prothrombinase complexes. In this paper, a modified Russell viper venom coagulation time test is used to quantitate material-induced procoagulant activity due to the generation of activated phospholipid surfaces. In our test system, polyethylene and Silastic™ tubes were filled with heparinized whole blood and left to gently flow back and forth at 37°C. After 1 h, the blood within the tubes was gravity drained and the plasma fraction assayed for procoagulant activity. The clotting times were determined by a Coag-A-Mate X2 instrument after the automated addition of Russell viper venom (to activate factors V and X) and calcium ions. Appreciable procoagulant activity was generated during whole blood contact within polyethylene and Silas-tic™ tubes although significantly greater activity was generated by the latter surface. As previously reported, plateletderived microparticles also were detected by flow cytometry. Filtration of the plasma after material contact through a 0.1 m filter led to substantial gains in clotting times and to near complete removal of microparticles, indicating that the material-induced microparticles likely were responsible for the procoagulant activity.