Fibrinolytic Activity in Animals of Different Species

Abstract

Studies have been made on the activation of animal plasminogen in vitro and in vivo. Whole blood lysis times and euglobulin lysis times were determined for animals of different species. Dilution enhanced spontaneous lysis time of dog blood but not of cattle, horse, sheep and rabbit blood. The dog blood contains proactivator and is activated by streptokinase. The initial streptokinase dose has been determined for dog blood in vivo. The blood of cattle, horses, sheep and rabbits was activated by urokinase which does not seem to require the presence of proactivator. A tissue activator was present in the lymph nodes, kidneys, spleen and heart muscle but not in the liver of rabbits. Autographs from fresh frozen sections confirmed areas of fibrinolysis around the blood vessels, especially in the region of capillaries and small veins. Two dogs on chlorpropamide showed a temporary increase in fibrinolytic activity and later developed resistance to the drug. Chlorpropamide had no fibrinolytic effect in rabbits.

Studies on the Specific Fibrinolytic Effect of Human Extrinsic (Tissue-Type) Plasminogen Activator in Human Blood and in Various Animal Species in Vitro

“…Mammalian blood contains an enzymatic system, called the fibrinolytic system which can dissolve blood clots, and which is composed of plasminogen, plasminogen activators and inhibitors. Although the fibrinolytic systems in several species are of similar composition, the concentrations of the components and the reactivity to certain stimuli may be quite variable (1)(2)(3).…”

Immunohistochemical and Histochemical Investigations on In Vivo Thrombolysis with Urokinase in Rabbits

“…The small increase in thrombolysis of the autologous artificial thrombi in the rabbits treated with urokinase in the present study may have the following reasons: (1) Human urokinase does not have a significant affinity for rabbit plasminogen (Irfan 1968), even though higher dosage was administered in the present experiment. The rate of activation of rabbit plasminogen by human urokinase was said to be smaller than that of human plasminogen (Hedlin et al 1972, Maki et al 1975, Mohler et al 1958.…”