Summary
The effect on the coagulation and fibrinolytic systems of various factor IX concentrates
after addition of heparin, antithrombin III or Trasylol to the concentrate before
infusion into dogs was studied in an attempt to characterize the clot-promoting activity
or activities in these concentrates. After infusion of Preconativ (AB Kabi; 100 u
factor IX/kg bodyweight) only small decreases of fibrinogen and platelet count in
the samples taken 1 and 4 hrs after infusion were found. Addition of heparin (10 u/ml;
5 dogs) or Trasylol (40 u/u factor IX initially followed by 10,000 u/h; 3 dogs) had
no effect but addition of antithrombin III (100 u/kg; 3 dogs) prevented all changes.
Infusion of Konyne (Cutter Laboratories; 100 u/kg bodyweight) induced marked decreases
of both fibrinogen and the platelet count at 1, 4 and 24 hrs after infusion and the
ethanol gelation test became positive. Addition of heparin (10 u/ml; 5 dogs) diminished
the changes but did not completely counteract them. Antithrombin III (100 u/kg; 3
dogs) added to the concentrate before infusion also reduced the induced changes to
about the same extent as heparin. Trasylol (40 u/u factor IX initially followed by
10,000 u/h; 3 dogs) did not seem to have any effect. Addition of both antithrombin
III and Trasylol (4 dogs) did, however, prevent almost all changes.
It is thus obvious that the two commercial factor IX concentrates used may contain
clot promoting activities and that these activities may differ between various concentrates.
