The heart of our research training program is participation by fellows in the conduct of investigation under the supervision of a member of our faculty. A major strength of the training program is the excellence and variety of research areas from which trainees can select their project. Our fellows have access to a wide spectrum of active research laboratories in which to pursue their investigative training. Aggregate research support, nearly all of it funded by NIH research grants, exceeds $2,500,000 per year. What follows is a brief description of current principal areas of active investigation.