Abnormal fibrin cross-linking profiles in clots obtained from the patient’s plasma in the presence and absence of Ca²⁺. (A) Normal (lanes 1 and 2) or patient (drawn 7/31/91; lanes 3 and 4) plasma (100 μL) was clotted in the presence of either 1 mmol/L EDTA (lanes 1 and 3) or 10 mmol/L CaCl₂(lanes 2 and 4) with 6 U bovine thrombin for 30 minutes at 37°C in a total volume of 500 μL, which also included 40 mmol/L Tris-HCl, pH 7.5, 80 mmol/L NaCl, and 10 U/mL Trasylol. The washed clots were reduced with DTT and analyzed by SDS-PAGE. (B) Normal (lanes 1) or patient (drawn 9/12/91; lanes 2) plasma (100 μL) was clotted in the presence of 1 mmol/L EDTA with 2.5 U bovine thrombin for 30 minutes at 37°C in a total volume of 500 μL, which also included 40 mmol/L Tris-HCl, pH 7.5, 80 mmol/L NaCl, and 10 U/mL Trasylol. The washed clots were dissolved in urea-SDS for electrophoresis on 2% agarose (lanes 1b and 2b) and also, after treatment with DTT, by SDS-PAGE (lanes 1a and 2a). Normal controls were collected from two different donors for the experiments shown in (A) and (B).