Studies of stroke in the population of Rochester, Minnesota, have been an important component of the Cerebrovascular Clinical Research Center. Recently completed studies were those which determined that there was no difference in prognosis among patients with TIA in the carotid arterial system and those with TIA in the vertebral-basilar system. Another study demonstrated the effect and risk of anticoagulant therapy and the effect of hypertension in cardiac disorders on survival and probability of stroke in patients with TIA. Studies in progress in the community include those on subarachnoid hemorrhage and the effect of pre-existing cardiac disease and/or hypertension as risk factors for completed stroke and TIA. Preliminary results of the use of ultrasonic B-scanning of the carotid artery indicate that the anatomy and morphology of the carotid bifurcation can be visualized in a large majority of patients and that there is close correlation between the angiographic and ultrasound studies in about two-thirds of the patients. A prospective study of patients with localized asymptomatic carotid bruit is underway. One hundred twenty-five patients have been enrolled in the study thus far and it is planned to enroll at least 500. Follow-up is accomplished every six months for this group. Computerized tomography and radionuclide imaging is being used in the evaluation of ischemic stroke. One hundred sixty-six patients have been evaluated thus far. The sensitivity of both of these types of study was about 60%. The findings thus far indicate that the sensitivity of both the CT scan and the RN scan depend on the volume of tissue infarcted and upon the interval between the stroke and the examination. Computer programs are being developed for the automated image analysis of CT scans. Ongoing clinical studies also include the follow-up of a large series of patients with carotid endarterectomy for unilateral carotid TIA and an analysis of the results of treatment of extracranial -intracranial bypass procedures for cerebral ischemia. Research in neurochemistry in this Center has been focused on the effect of the reduction of energy source on cellular structural elements of the brain, namely protein, ribonucleic acid and lipid. From experimental models, we have found that the ability of protein synthesis is very vulnerable to nitrogen atmosphere or to ischemia from common carotid ligation in gerbils. Rapid disaggr (Text Truncated - Exceeds Capacity)