FIBRINOLYTIC ACTIVITY IN ANIMALS OF DIFFERENT SPECIES

¹ Department of Clinical Veterinary Sciences, Trinity College, Ballsbridge, Dublin 4

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.

Note:

I am grateful to Professor R. A. Q. O'Meara for his valuable suggestions, and to Miss J. Davies for her technical assistance.