Effect of TF on uPA- and plasminogen-mediated fibrinolysis. scuPA (1 μmol/L) was added to a fibrin clot in PBS (A1 and B1) or PBS containing 14 nmol/L TF (A2 and B2) or TF without tcuPA (C1 and C2) for 2 hours. The clot was incubated with trypan blue, washed, photographed, and scanned, and its size was measured by densitinometric analysis as described in the Materials and Methods. The fibrin clot measured 0.75 and 0.84 cm² in the absence of TF and 0.18 and 0.22 cm² in the presence of TF. The data shown are representative of three experiments so performed. TF caused a similar increase in clot size when tcuPA (1 μmol/L) was substituted for scuPA.