Summary
Increased heparin resistance was found to remain unchanged in BaSO4-adsorbed plasma, but disappeared following adsorption with large quantities of Al(OH)3. The factor V content in the plasma could be considerably reduced without any alteration
in the heparin resistance. Antihaemophilic globulin exerted no influence upon the
heparin thrombin time. Tissue thromboplastin in quantities sufficient to accelerate
the clotting of recalcified plasma considerably, did not affect the heparin thrombin
time. Plasma thromboplastin had no antiheparin effect. Increased heparin resistance
was — although usually less marked — still demonstrable in most cases in plasma defibrinated
with thrombin from patients with a greatly shortened heparin thrombin time, but not
in cases of less pronounced shortening. Fibrinogen prepared by the freeze-thaw technique
from normal plasma and patient plasma showed no difference in reactivity to heparin
and thrombin. In experiments on plasma mixtures, a shortening of the heparin thrombin
time was still demonstrable at the ratio 9 parts of normal plasma to 1 part of plasma
from patients with greatly increased heparin resistance. The antithrombin content
of plasma was not reduced in increased heparin resistance.
