X-Message-Number: 33280
Date: Thu, 27 Jan 2011 06:07:30 EST
Subject: Actuarial Tables

Content-Language: en

In a message dated 1/27/2011 2:02:45 A.M. Pacific Standard  Time, 
The most striking  thing clearly is the steady  reduction in mortality  
rate with  advancing age. A man of 80 can only expect about 7.28 years more, 
but if  he reaches 90 he still can expect another 3.84 years. Escape  
velocity, anyone?

MD: Ah, I wish! What is actually going on here is  interesting, but alas 
doesn't portend immortality, or a pathway to it. The  folks who live to be 

centenarians and super-centenarians are extraordinary  people who represent the
extreme of a continuum of long-lived people. They  have a number of things 
in common, including lower than average growth  hormone levels, high HDLs, 
superior protection against cancer, and very  likely, genes that protect 
against obesity and minimize free radical injury.  There are undoubtedly other 
biological and environmental factors, but these  are the things that 

currently stand out. Interestingly, it is possible to sort  those who will not 
past 100 from those who will with a fair degree of  precision by looking at 
their medical histories and cognitive functioning.  Super-centenarians, in 
particular, experience 'low inflammation aging' and  virtually never suffer 
from degenerative disease until well into their 90s, or  beyond. They 

similarly remain cognitively intact into their 90s, and in this  respect, men do
much better than women! That's encouraging and useful  information for 
However, it is important to understand that even these  super-agers are 

biologically doomed - for now. Perhaps one of the few redeeming benefits of the
atmospheric  testing of atomic weapons during the 1950s and '60s is that it 
resulted in a  large pulse of atmospheric 14C, which subsequently found its 
way  into developing fetuses undergoing gestation at this time. This  

peculiarity was first applied to  carbon dating of lens crystallins  proteins by
comparing the 14C concentration of the lens crystallins  to the "bomb pulse'
 of 14C release that occurred during the era of  atmospheric nuclear 

weapons testing.  As it turns out, 14C  concentrations fluctuated distinctively
year by year with the number of open  air tests, and this has allowed for 

precision dating of the crystallin  proteins. The results of these studies have
proved conclusively that almost  all lens crystallins are elaborated during 
fetal development, with only  miniscule (and steadily decreasing) additional 
synthesis over the course of  life.(Lynnerup N, Kjeldsen H,  Heegaard S, 
Jacobsen C, Heinemeier J (2008) Radiocarbon Dating of the Human  Eye Lens 

Crystallines Reveal Proteins without Carbon Turnover throughout Life.  PLoS ONE
3(1): e1529. doi:10.1371/journal.pone.0001529.) This really  isn't 

surprising, and it confirms what many ophthalmologists and  gerontologists had 
suspected. However, this technique has also been applied to the nuclear DNA 
of brain  neurons, with careful control for local (i.e., regional  

geographical) variations in 14C levels, as well as study good  design to exclude
possible contribution to the 14C of neuronal  DNA via methylation. The result 
of this study has demonstrated conclusively  that there is essentially no 
neuronal  cell division in the cerebral cortex of humans after the perinatal  
period.  (Spalding KL, Bhardwaj RD, Buchholz BA, Druid H, Frisen  J. (2005) 
Retrospective birth dating of cells in humans. Cell.  122:133-43.) In the 
case of both neurons and glial cells, what we are  born with is all that we 
will have for the remainder of our lives._[1]_ 

(aoldb://mail/write/template.htm#_ftn1)   While neuron components such as cell 
membranes, organelles, and 
vesicles  undergo dynamic molecular turnover, neuronal and most glial cell 
DNA remain  atomically unaltered throughout life! The atoms in your brain DNA 
you are born  with, are the atoms you will die (or be cryopreserved  with).
This has interesting implications, because gray matter neuron loss  is 
virtually linear with age, and continuous from age 2 throughout life. White  
matter losses are also linear, but begin later in life. This makes sense when  
considered in the context of the amount of DNA damage per cell per day which 
 has been estimated at ~ 1 million molecular lesions daily! (Lodish H, Berk 
A, Matsudaira P, Kaiser CA,  Krieger M, Scott MP, Zipursky SL, Darnell J. 
(2004). Molecular Biology of the  Cell, p963. WH Freeman: New York, NY. 5th 
ed.) Super-centenarians also  experience this relentless loss of gray and 
white matter, but at a much slower  rate. This may be due to better protection 
against DNA damage, better DNA  repair, or both. But, in any event, it seems 
that the brain (and a number of  other vital structures and tissues), have 
no built-in replacement programs;  and this is confirmed by the absence of 
evidence of DNA methlyation, as  well (at least in us humans). So, barring 
the advent of fairly sophisticated brain  rejuvenation technology, we will 
eventually end up as neurological Struldbrugs,  since we are losing neurons 
with each passing day - and at an  astonishing (and to me, very disconcerting) 

Yet another reason why cryonics is likely to be  essential for many of us 
who may not make it to such definitive rejuvenation  technologies.
Mike  Darwin


_[1]_ (aoldb://mail/write/template.htm#_ftnref1)  By  contrast, the average 
age of non-epithelial intestinal cell nuclear DNA is  ~15.9 years and 

skeletal muscle DNA was found to have an average age of 15.1  years. The mean 
of cerebrocortical   and cerebellar gray-matter DNA was only 2.9 years 
younger than the  person. The gray matter of the occipital cortex demonstrated 
the most turnover  with non-neuronal DNA being ~10 years younger than the  

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