Author/Editor		Blinc, Aleš
Title		Vpliv načina prenosa urokinaze v krvne strdke na njihovo raztapljanje
Type		monografija
Place		Ljubljana
Publisher		Medicinska fakulteta
Publication year		1994
Volume		str. 95
Language		slo
Abstract		We tested the hypothesis that the rate and spatial pattern of blood clot lysis are determined by the mode of transport of fibrinolytic agents into the clot. The shapes and sizes of blood clots undergoing pharmacological lysis in vitro were measured by magnetic resonance imaging. Urokinase was transported into cylindrical blood clots from the surrounding plasma either by diffusion alone or by bulk flow under a pressure gradient. Retracted and non-retracted blood clots lysed 10 to 100-times faster when exposed to bulk flow of urokinase under an initial pressure gradient of 1.2-1.7 kPa/cm (3.7-5 kPa slonh occlusive, 3 cm long blood clots), as compared to the rate of lysis under diffusion of urokinase in the absence of a pressure gradient. The mode of plasminogen activator transport into the clots determined not only the rate but also the spatial pattern of lysis. By diffusion of plasminogen activator the clots lysed slowly, but uniformly along the plasma-clot boundary. In contrast, under a pressure gradient plasma carrying the plasminogen activator not only penetrated into different regions of the same blood clot with different velocities but also completely by-passed cartain areas. Lysis that followed permeation of lytic plasma with a time-lag thus proceeded along meandering channels that left substantial parts of the blood clot nondissolved. The different spatial patterns of fibrinolysis were described mathematically in terms of transport-limited enzymatic reactions proceeding inside a fibrin gel with random distribution of pore sizes. The results of mathematical modelling w ere strikingly similar to the observed patterns of blood clot lysis, which confirms the dominant role of the mode of reactant transport in determining the rate and pattern of blood clot lysis.
Descriptors		THROMBOSIS FIBRINOLYSIS UROKINASE MAGNETIC RESONANCE IMAGING MODELS, THEORETICAL GELS DIFFUSION PERFUSION