Penetration of macromolecules into contracted blood clot.

The effectiveness of thrombolytic therapy is determined by accessibility of thrombus compartments to plasminogen activators and, therefore, depends on permeability of thrombus to blood born macromolecules. Accumulation of 125I labeled proteins with molecular massess ranging from 150 to 450 kD into partly contracted blood clot or plasma clot was consistent with diffusion coefficients 3.2 x 10(-11) and 2.7 x 10(-11) m2 s-1, respectively. So far as the model conditions imitated those for venous thrombi, these data indicate that such thrombi are porous enough for immunoconjugates of relatively big size.