Design: The study is open-label, dose escalation, safety and proof of principle study of the combination of intravenous abciximab and reteplase. A fixed dose of abciximab will be used in all patients: 0.25 mg/kg bolus (to a maximum of 30 mg) followed by a 0.125 microgram/kg/minute infusion (to a maximum of 10.0 microgram/minute) for 12 hours. The five dosing groups for the reteplase dose are 0U, 2.5 U, 5.0 U, 7.5 U, and 10.0 U. A maximum of 72 patients will be treated using an adaptive statistical design. Non-investigation patient management will be standardized across all patients according to the NIH Stroke Center Clinical Care Pathway.