X-Message-Number: 15711
Date: Wed, 21 Feb 2001 18:38:46 -0800
From: Hugh Hixon <>
Subject: Current Alcor Procedures

Re Ettinger's message #15699, which is reproduced below:

The current state of affairs is that Alcor is doing the vitrification
protocol for
neuropreservation only.  For our whole-body members, we still are using
glycerol perfusion as I have described (#15693) because the new protocol is
more difficult to apply due to the differences of perfusing a whole human
patient versus just perfusing the structures of the head.  Until we are able
to offer a new protocol for whole-body, we are recommending to our
whole-body members that they reconsider their choice.  And of course, we
still recommend neuro for the reason that it is much easier to concentrate
our cryoprotection efforts on the single organ we consider irreplacable, the

Ettinger is correct that the Web site has not been updated to reflect this
change.  The speed with which advances are being made has demanded attention
to implementation at the the expense of updating information.  There will be
more details in the upcoming issue of *Cryonics*.

MHP-2 is not exactly secret, but you have to burrow back in old issues of
*Cryonics* to find it (sorry, no cite).  The difference between MHP-1 and
MHP-2 is minor.  MHP was developed as an organ preservation/resuscitation
solution, and at the end of our experimental series in the mid-'80s we were
routinely recovering dogs after four hours of  circulating bloodless
(hematocrit <1) perfusion at around 5C, which is what we expected would be
the maximum time
a cryoprotection would require.  How routine?  The dogs had normal behavior
in all respects as soon as they recovered from the anesthetic, except for
some hind leg weakness due to the femoral vascular access approach. The
patent for MHP is 5 082 831, but it's kind of fuzzy, as most patents are to
broaden the claims.

Descriptively, MHP is an intracellular perfusate (that is, the electrolyte
concentrations resemble the cell interior electrolyte concentrations, to
minimize changes in the intracellular milieu during the period of reduced
metabolism, and to reduce the startup burden on the cell as metabolism is
resumed and normal electrolyte concentrations are achieved); several
substrates that replace those drained out of the metabolic system during
metabolic arrest; mannitol (M) as the extracellular osmotic agent;
hydroxyethyl starch (H) as the oncotic agent (keeps the tissues from
becoming edematous during the prolonged perfusion required by
near-equilibrium cryoprotection); and the organic buffer HEPES (another H,
but using it would less euphoneous) for pH control and to prevent calcium
precipitation (which is a problem with the inorganic buffers used by the
body).  P, by the way, is "Perfusate".

MHP resembles Viaspan, except that the buffer/osmotic agent is lactobionic
acid, which is rather expensive.  A head-to-head, N=1 experiment that we did
indicated that MHP was better that Viaspan, at least for rabbit kidneys.
Most organ preservation solutions are optimized for a particular organ, and
the Viaspan patent (4 798 824) actually describes different compositions for
different organs.  Viaspan's target organ is the liver.  Alcor used Viaspan
in its transports for a number of years, simply because of its commercial
availability and packaging, but more recently we have packaged MHP-2 for
ready use.  And of course, MHP-2 was optimized for the whole animal,
including the brain.

As to the vitrification cryoprotectant, that is proprietary, except that ice
blockers are used as has been described to reduce the amount of
cryoprotectant needed for vitrification.  The composition Alcor uses is
subject to change, as it is still being optimized.  Even now, however, it is
definitely superior to glycerol by a large margin.  Among the simple
cryoprotectants, glycerol is merely the best of a rather poor selection, and
we have understood this for a good many years, without necessarily knowing
that a better cryoprotectant is possible.

Hugh Hixon
>Message #15699
>Date: Tue, 20 Feb 2001 10:36:58 EST
>Subject: Hixon
>Thanks to Hugh Hixon for #15693 explaining Alcor's current procedure.
>I am very much surprised. Since this procedure is based on glycerol, I 
>thought it was just a left-over in a web segment that needed updating. All 
>the excitement in recent years in Alcor's magazine had centered on "new" CPAs 
>such as glycol ethers. We had heard suggestions that still newer research had 
>already outmoded the glycol ethers, but I hadn't imagined that this meant 
>back to glycerol.
>If my understanding of Hugh's post is correct, then the current Alcor CPA is 
>not secret, except for the formulation of "MHP-2," what we would call the 
>"washout solution," or corresponding to the former use of Viaspan. Plus there 
>remains secrecy about the details of the procedure used to attain rapid 
>cooling, which presumably is related to the patent I mentioned a while back. 
>Perhaps I have misunderstood or misinterpreted something, but if what I have 
>written here is correct, then the only substantive change in the Alcor 
>procedure has been the use of perfluorocarbons or some such to achieve rapid 
>cool-down, hopefully allowing vitrification. 
>Robert Ettinger

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