Research in our laboratory is directed toward the study of lipoprotein-cell interactions as well as the intracellular control of cholesterol, cholesteryl ester, and triacylglycerol metabolism in human skin fibroblasts. Over the past 12 months, we have developed assays for human fibroblast acid ester hydrolase and neutral ester hydrolase. We have used these assays to characterize cholesteryl ester and triglyceride catabolism in normal cells as well as in cells from a new case of Wolman's Disease, cholesteryl ester storage disease and a previously uncharacterized lipid storage disease. We have also devised a new technique to measure lipoprotein binding to fibroblasts and are evaluating these interactions in cells from normal as well as patients with dyslipidemia and atherosclerosis. Studies addressing substrate specificity for sterol-ester metabolism in fibroblasts from normal humans and from patients with beta-sitosterolemia have been completed. Finally, outpatient studies evaluating Neomycin and Niacin in type II hyperlipoproteinemia and Niacin in types III and V hyperlipoproteinemia have been designed and instituted.