Transmission electron micrograph of capillary rat intestine fenestrated endothelium. One of Dr. Palade's long standing interests concerned the structure and function of capillaries. He and his many colleagues identiified a varitey of types of capillary endothelium (fenestrated, continuous) and determined the role of caveolae in transporting macromolecules across endothelial cells. Collaborators included: Nicolae and Maya Simeonescu and Romaine Bruns Image made available by James D. Jamieson and the Department of Cell Biology, Yale University School of Medicine.