抄録
We have noticed the elevated dynamic viscoelasticity during process of blood coagulation in patients with various kinds of thrombotic disease, observed by using the viscoelastorecorder. We have confirmed that dynamic viscoelasticity of whole blood clots correlates with the concentration of fibrinogen but opposing with hematocrit level. We studied the effect of platelet count and platelet aggregation inhibitors on clotting curve.
Dynamic viscoelasticity was measured by the viscoelastorecorder and was shown by absolute values, namely dynamic elastic modulus (G′) and loss modulus (G″). Experimental conditions were: temperature, 25.0°C; oscillation of outer cylinder, 3c/s, amplitude; 60μm from peak to peak; and citrate and CaCl2 solutions were used as an anticoagulant and for recalcification.
According to experiment, the elevated dynamic elastic modulus of plasma clots were obtained in cases of increased platelet count. Also other physical characteristics, such as dynamic loss modulus, maximum clotting gradient (MCG′) and tangent delta (G″/G′) correlated with platelet count.
In order to observe the effects of platelet aggregation inhibitors, we recorded clotting curve of platelet rich plasma with dipyridamole and aspirin respectively. Dipyridamole reduced by 50% of maximum dynamic elastic modulus (G′m) of clots to the control under the final concentration of 3×10-4Mol for 15min. incubation at room temperature. However clotting time and maximum clotting gradient were not reduced. From these observation, it is supposed that dipyridamole does not affect on the thrombin formation and fibrin polymerization but does on fibrin polymer cross linking mechanism. Under the final concentration of 2×10-4 Mol for 15min. incubation at room temperature, aspirin has no significant effect on dynamic viscoelasticity of clots.
