[NOTHROMBEL EFFECT ON THE FORMATION OF PLATELET-LEUKOCYTE COMPLEXES INDUCED BY THROMBIN].

The effects of the Nothrombel on the formation of platelet-leukocyte complexes (PLCs) induced by thrombin was studied. It was shown, that Nothrombel dose-dependently inhibited the formation of PLCs. Its activity is higher than the activity of the comparison compounds Aspirin.

[NOTHROMBEL EFFECT ON THE EXPRESSION OF MEMBRANE COMPLEX GPIb-IX-V PLATELETS ACTIVATED BY THROMBIN].

The influence of Nothrombel on the expression of membrane complex GPIb-IX-V of platelets activated by thrombin was studied. It is established that Nothrombel reduced thrombin-induced expression of complex GPIb-IX-V on the membrane of the activated platelets. The inhibitory activity of Nothrombel on the expression of GPIb (CD42b) was comparable to its activity with respect to GPIX (CD42a) and is equal to 43 %.

[Influence of new N,N'-substituted piperazines on thrombin-induced platelet activation].

We have studied the influence of new N,N'-substituted piperazines with variable nature of the linker between piperazine and aromatic cycles (carbonyl group in VR-0411 versus sulfonyl group in VR-0511) on thrombin-induced platelet aggregation, cytoplasmic Ca2+ mobilization in platelets, and P-selectin exposure on the platelet plasma membrane. The inhibitory effect of VR-0511 on platelet aggregation exceeds the effects of the reference compound aspirin and VR-0411 by 35 and 42%, respectively (p < or = 0.01).