reply to larry and jim
ST401896 at BROWNVM.BROWN.EDU
Mon Mar 30 09:48:52 EST 1992
I believe children do not display the manifestations of
ageing because they start out with essentially a clean slate of DNA (one
of the amazing things about sexual reproduction is that the child
possesses few of the errors of either parent). Ageing is a balance
between DNA damage and repair. Children have the same repair rate as
adults (say 99.95%), but less damage. Eventually, even this amazingly
good rate of repair can't keep up with the accumulated damage and then.
As to whether there are other mechanisms besides free radical damage, I
haven't heard of any. Please bring them to my attention. Osteoporosis could
be due radical induced damage of the proteins involved in Ca storage.
As to collagen crosslinking, it is well known that polymers can be
crosslinked via radical mechanisms. As to baldness, I dont think anyone
really understands what causes it. Baldness may not be a sign of ageing.
It may just be the expression of a gene (or lack of expression)
at a certain time, just as puberty is.
More information about the Ageing