This is a phase 2 randomized, blinded and controlled safety study in patients with ischemic stroke. The time window for enrollment will be within 0-24 hours of symptom onset. For patients who are found with the stroke on awakening, it will be assumed that the stroke occurred the last time that the patient was known to be normal. All patients will be identified by the stroke acute care team in the emergency room of the participating centers, or in some cases, on the floor services of the hospital (i.e., for patients with stroke occurring in hospital). If preliminary data indicate that the patient meets eligibility criteria the patient (or legally authorized representative) will be approached about participation in the study, and consent obtained. Surrogate consent will be allowed at centers at which this is permitted according to regulations. Patients who are consented through a surrogate and subsequently regain capacity, will be approached and reconsented to continue in the study.