Introduction

From early antiquity, medical science has been fascinated by the gradual loss of function that occurs with aging. One compelling reason for this interest has been the universality of the aging process, its threat extending to both the eager investigators and their patrons. The philosopher’s stone was sought not only to translate base metals into gold, but also to yield an elixir that would allow the alchemist leisure to contemplate his new-found wealth (Comfort, 1979).