Word: spans
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Dates: during 1990-1999
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...record numbers, they are lapping up a freshet of books about how to turn back the clock. Life expectancy in the U.S. is at an all-time high. A newborn boy can expect to reach 73.4 years, and a newborn girl 79.3. But extensions of the average life span apparently just make us greedy for a longer, healthier life. That's where fountain-of-youth books come in. Depending upon the author, they promise to help you live longer--to 100 or even beyond...
...20th century medicine did little to increase the natural life-span of healthy humans. The next medical revolution will change that, because genetic engineering has the potential to conquer cancer, grow new blood vessels in the heart, block the growth of blood vessels in tumors, create new organs from stem cells and perhaps even reset the primeval genetic coding that causes cells...
...terms of aging. As we grow older, changes occur in our cells that reduce the number of times they can reproduce. This clock of age is reset by normal reproduction during the production of sperm and eggs; that is why children of each new generation have a full life span. It is not yet known whether aging is reversed during cloning or if the clone's natural life is shortened by the years its parent has already lived. Then there is the problem of the genetic errors that accumulate in our cells. There are systems to seek out and correct...
Scientists have tried ever since to reactivate the enzyme that lengthens the tips, known as telomeres. Last January they succeeded: Andrea Bodnar and colleagues from the Geron Corp. in Menlo Park, Calif., activated the enzyme telomerase, extended the telomeres and lengthened the life-span of cells in culture by at least 20 divisions past the Hayflick limit. In November, Geron scored another first by reconstituting the telomeres of embryonic stem cells, which are renowned for their ability to turn into any type of cell, making it theoretically possible to rejuvenate parts of any organ with a simple injection...
...Over the last three years Harvard has recruited a really stellar group of faculty that span these departments who have overlapping interests in social issues," Newman said...