Increased shear stress- and ristocetin-induced binding of von Willebrand factor to platelets in cord compared with adult plasma.

Multiple indications do exist that the extensive neonatal platelet adhesion and aggregation, and the shorter closure time of neonatal compared with adult whole blood in the platelet function analyzer 100 are attributable to the physiological high plasma concentrations and high concentrations of unusually large von Willebrand factor (vWf) multimers in neonates. However, to date the direct experimental evidence is lacking. Therefore, we compared in the present study the ability of neonatal vWf to bind to platelets to that of adult vWf.

[Correlation between molecular parameters of hyaluronic acid and viscoelasticity of synovia].

The viscoelastic properties of hyaluronic acid solutions and synovial fluids were investigated by oscillating capillary rheology in a frequency range from 0.03 to 30 Hz. A clear dependency of these parameters, especially of the elastic component, on the molecular weight of the hyaluronic acid molecules was obtained.