Aptamer RA36 inhibits of human, rabbit, and rat plasma coagulation activated with thrombin or snake venom coagulases.

RA36 DNA aptamer is a direct anticoagulant prolonging clotting time of human, rabbit, and rat plasma in the thrombin time test. Anticoagulant activity of RA36 is lower than that of recombinant hirudin. During inhibition of human plasma clotting activated with echitox (coagulase from Echis multisquamatus venom), the aptamer presumably binds to meisothrombin exosite I.

[Comparative in vitro study of anticoagulant activity of RA36 DNA aptamer in human, rabbit, and rat blood plasma].

DNA aptamer RA36 with a molecular weight of 10000 is direct-acting anticoagulant whose efficacy is lower than that of recombinant hirudin and unfractionated heparin (UFH) in blood clotting time (BCT), activated blood recalcification time (ABRT), recalcification time (RT), prothrombin time (PT), and activated partial thromboplastin time (APTT) tests. The anticoagulant effect of RA36 is comparable with that of UFH in the thrombin time (TT) test, but is lower than the effect of recombinant hirudin. Analysis of the blood and plasma anticoagulant activity during intravenous bolus administration of aptamer RA36 in rabbits and rats is based on the use ABRT (in blood case) and APTT/RT (in plasma case) tests.

[Antithrombotic and hemorrhagic activities of fucoidan isolated from Fucus evanescens brown algae].

The antithrombotic and hemorrhagic activities of fucoidan with molecular weight within 20 - 40 kD isolation from Fucus evanescens seaweed have been investigated. The antithrombin activity of fucoidan is 41 +/- 9 aIIa IU/mg and the anti-factor Oà activity is 38 +/- 8 aOà IU/mg. The antithrombin and anti-factor Oà activities of plasma, antithrombotic activity (100% prevention of formation of a blood clot observed at a dose of 10 mg/kg), and hemorrhagic activity (to a lesser degree, than that of unfractionated heparin in comparable antithrombotic activity doses) increase as the doses of fucoidan increases from 2.