X-Message-Number: 4990
Newsgroups: sci.cryonics
From:  (Brad Templeton)
Subject: Re: Dendritic spines
Date: Fri, 13 Oct 1995 19:02:57 GMT
Message-ID: <>

References: <45i9tf$> <> 
<>

In article <>, Brian Wowk <> wrote:
>	We are talking about far more than just high-level memory
>loss.  The cited study reports a ~60% loss of dendritic spines after
>6 hours of cold ischemia.  This is equivalent to end-stage Alzheimers,
>and near complete neurological disfunction.  If you revive a dog after
>6 hours of ischemia, and it responds to its name, the people it knows,
>and runs and plays like it always did, there's no darn way it lost
>60% of its dendritic spines. 

I was not aware that Alzheimers was that well understood.  Ie. I did not
know it was known that the spines were the cause.  Is it no possible that
while the spine degredation is part of the disease, the more total memory
losses have other causes.

At any rate, my understanding is that often even when patients lose almost
all identity oriented memories, so they no longer know their home or family,
they still have things like language -- something a dog never has.  So I
don't follow that you can extrapolate higher memory performance from dogs.

At present time our neurological understanding is limited enough that you
simply must attempt to protect as much of the brain as you can observe.

In fact, I would even advocate a philosophy of being conservative when it
comes to liquid nitrogen temperature.  Should it be possible to hold a
subject above the glass transition temperature, even at higher cost, this
option should be considered.  The reason is you don't have to hold them
there until reanimation -- only until you know more about suspension and
the effects of the cracking, which might be not too long.  Technology 
improves all the time, and the goal should be to do the minimum damage you
can -- even if that means a costly refrigeration that you couldn't support
for 100 years, because worst case, you can always dump into LNO if no
new technology comes up in 10 years.
-- 
Brad Templeton, publisher, ClariNet Communications Corp.	 
The net's #1 Electronic newspaper		     http://www.clari.net/brad/


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