Never before -in human history has so much been known about our bodies and the molecular mechanics that dictate their function. Even though people are living longer, with the percentage of Americans aged 65 and older rising from 4% in 1900 to 13% in 1998, little is known about why we become old. Among the challenges that greets the dawn of this millennium is how can we maintain good health and postpone or reverse old age along with its debilitating …showed first 75 words of 520 total…

…showed last 75 words of 520 total…contribute to age-related memory deficits and neurodegenerative diseases. In addition, many proteases that play essential roles in regulating neuropeptide metabolism, amyloid precursor protein processing, and neuronal apoptosis are up-regulated in the aged brain and likely contribute significantly to brain aging. Finally, a subset of these genes whose expression is affected by aging are oppositely affected by exposure of mice to an enriched environment, suggesting that these genes may play important roles in learning and memory.