The Arteriosclerosis SCOR at Columbia comprises a multidisciplinary and coordinated set of clinical and laboratory research activities within the broad field of atherosclerosis research. The SCOR program includes projects directed at major questions in the areas of lipid and lipoprotein metabolism, hyperlipidemia, atherogenesis, thrombosis, and coronary artery disease. Two major integrating themes are: (1) the detailed and extensive study of patients with hyperlipidemia; and (2) studies of interrelationships between lipoproteins, platelets, and the arterial wall. The proposed SCOR will be organized in 7 Units. Unit #1 will comprise the core facilities and functions of the SCOR: SCOR administration; the core research clinic; the core lipid laboratory; a core biomathematics resource; a core tissue culture laboratory; and a core ultrastructure resource. Unit #2 includes projects on cholesterol turnover and metabolism in normal and hyperlipidemic humans, and on the chemistry, the metabolism, and the metabolic regulation of plasma retinol-binding protein. Unit #3 aims to explore the normal and abnormal regulation of regional coronary blood flow in experimental animals and in humans. Unit #4 will aim to investigate relationships between the hemostatic system and atherosclerosis, including studies on the interactions between endothelial cells, platelets, and blood components involved in coagulation and fibrinolysis. Unit #5 deals with the metabolism of plasma lipoproteins and apolipoproteins in humans and particularly with the metabolism and turnover of apolipoprotein E. Unit #6 aims to delineate the role of the intestine in the production and metabolism of high density lipoproteins, and in the regulation of plasma HDL levels. Unit #7 will aim to explore relationships between the platelet-derived growth factor and the cell biology of the arterial wall.