>From: Eugene Leitl <eugene.leitl@lrz.uni-muenchen.de>
>Reply-To: extropians@extropy.com
>To: extropians@extropy.com
>Subject: Re: cryonics sources: a third alternative
>Date: Mon, 19 Jun 2000 22:45:16 -0700 (PDT)
>
>Robert Bradbury writes:
>
> > Getting through the skull is a minor problem I presume... Or have
> > you removed the brain and spine???
>
>Cutting is a seriusly bad idea (if you really want it, then why not
>LN-cooled isotopically pure diamond knifes? ;) -- you wouldn't want to
>cut a platter full of porridge, wouldn't you? I recommend going to
>your local slaughterperson, and obtain a relatively fresh animal
>brain. Try moving it, and handling it. It does really tell you a lot
>more than theoretizing about an object one has never held in one's
>hands.
>
>Of course, one can dremel the skull open after perfusion with
>cryoprotectants, but it's tedious (=slow, and can be a source of
>mechanical injury), and the brain will tend to deform under its own
>weight because of lack of floatation due to absence of
>liquor. (Dremelling in a vat of liquid is a nighmare, at least for
>current humans -- sonar/touch guided robots might be different, but
>who's going to develop them?). It takes forever, is surprisingly
>messy, but is probably useful if you want to vitrify the brain
>(viscosity will soon prevent you from anything put passive thermal
>conduction cooldown).
>
>If there is really a threshold where current vitrification agents
>can't cool down human sized brain cleanly before massive nucleation
>occurs (I'm only talking about vitrification here, obviously), you
>could always attempt to bisect it *very* carefully. But, I don't think
>this is an issue at all. Use conservative approach, unless it's
>obviously failing. Do not hurt the patient unnecessarily, that's what
>experimental animals are for.
>
> > I doubt the cooling rate matters much. There is still residual brain
> > activity in comatose patients or patients who have been dead for hours.
>
>Well, your EEG is sure flat <20 s after you arrest. At that point
>you've burned all your local ATP and the oxygen.
>
> > Since the brain is sterile you aren't going to have bacteria consuming
> > anything (as would be the case in the gut). Since you are out of ATP
> > you can't do any breakdown (or construction) that requires energy.
> > So so long as the non-energy requiring enzymes in compartments like
> > the lysosomes remain in their compartments, not much is going to
>happen.
>
>Ideally, there should be no arrest.
But since we have all these religious types telling everyone what to do, we
can't legally do that, can we?
Just another way the religion of the majority invades the lives of
everyone...
________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com
This archive was generated by hypermail 2b29 : Thu Jul 27 2000 - 14:13:53 MDT