This volume contains the proceedings of the International Symposium on Function and Biosynthesis of Lipids held November 1976 at Sierra de la Ventana, Argentina. The conference was organized by the Argentine Biochemical Society and co-sponsored by the International Union of Biochemistry and the Pan American Association of Biochemical Societies. The Symposium's great success is owed to all the participants, most of whom were actively involved in the interesting and stimu- lating discussions that followed every single lecture and communi- cation delivered. Many thanks also to Drs. R. Anderson, S. Bonting, K. K. Carroll, B. Cecarelli, M. A. Crawford, R. T. Holman, J. Mead, R. H. Michell, G. Porcellati, W. Stoffel, W. Thompson, and H. Wiegandt for chairing Symposium sessions. The contributions are organized in four sections, preceded by the opening lecture on the role of dolichol phosphate in glyco- protein biosynthesis delivered by Dr. Luis F. Leloir. The first section, on aspects of lipid involvement in the biogenesis of mem- branes, covers the biosynthesis of saturated and unsaturated fatty acids, including enzymology, biosynthetic pathways, and regulation and modifications during development, in the fetus and in tumor~ cells. Papers on the composition and assembly of membrane compo- nents, lipid interactions with proteins and enzymes, developmental changes of lipids, and newer approaches to survey the organization and biogenesis of cellular membranes complete this section. New information as well as reviews of current concepts about structural specificity, biosynthesis, and function of glycosphingo- lipids are included in the second section.

For the past 100 years the mainstay of therapy for rheumatoid arthritis (RA) has been aspirin or other drugs of the non-steroid anti-inflammatory group. In 1971 Vane pro posed that both the beneficial and toxic actions of these drugs was through inhibition of prostaglandin synthesis. The recent discovery that prostaglandins responsible for pain and other symptoms at inflammatory foci are synthesized by an inducible cyclooxygenase (COX-2) that is encoded by a gene distinct from that of the consti tutive enzyme (COX-I) provided a new target for therapy of RA. A drug that would selectively inhibit COX-2 would hopefully produce the symptomatic benefit provided by existing NSAIDs without the gastrointestinal and renal toxicity due to the inhibition of COX-I. Drugs selective for COX-2 are now available. Experimental studies have shown them to be effective with minimal toxicity, and in clinical trials gastric and renal toxicities are less. Highly selective COX-2 inhibitors, perhaps designed with knowledge of the crystal structures of COX-I and COX-2, are also available. Other experimental studies, including those in animals lacking effective genes for COX-lor COX-2 and in experimental carcinomas, suggest there is still much to be learned of the pathophysiological functions of these enzymes. The inflammatory response is a complex reaction involving many mediators that derive from white blood cells, endothelial cells and other tissues. Preliminary data have revealed that inhibitors of the cytokines and adhesion molecules that play a crucial role in the migration of white cells to inflammatory sites may be useful in RA.