Acute hemostatic effect in tail bleeding model in hemophilia B mice. N9-GP or rFIX was given IV at 0-0.75 mg/kg to HB mice 5 minutes before tail-tip transection (4 mm). (A) Bleeding time and (B) blood loss were recorded for the after 30 minutes. Data are shown as mean ± SEM (n = 6-14/group). The bleeding pattern in normal (C57BL) and vehicle-treated HB mice are included for comparison. (C) FIX levels were measured by ELISA at the end of each observation period. Linear regression analysis yielded slopes of 3.8 ± 0.3 and 1.8 ± 0.3 (μg/mL) (mg/kg)⁻¹ for N9-GP and rFIX, respectively.