X-Message-Number: 2404
From: whscad1!kqb (Kevin Q Brown +1 201 386 7344)
Subject: CRYONICS How Much Cracking Really?

I have appended below a brief article from the August 1993 issue
of The Immortalist.  It concerns the cracking problem, which
prompted the long and productive "cold room" thread on CryoNet
a few months ago. **  Robert Ettinger reports that cracking has *not*
been observed in recent experiments at CI and BioTime and thus calls
into question the need for a "cold room" to prevent cracking.
Can anyone shed more light on this?
                              Kevin Q. Brown
                              INTERNET    
                                 or       
PS: I assume that electronically distributing the article below
    to a small group of people falls under the "fair use" doctrine
    of copyright law.  Alternatively, consider it a free advertisement
    for The Immortalist.  (For contact & subscription information for
    The Immortalist and other cryonics-related publications,
    send email to me with the Subject line "CRYOMSG 0004".)
 ** The cracking problem is that organs, and people, frozen to liquid
    nitrogen temperature, crack.  I think that this is mostly due to
    unequal contraction of adjacent tissues.  These cracks become obvious
    upon rewarming.  Although the cracks are generally "clean breaks",
    they are numerous enough and large enough to cause massive disruption
    of tissues.  If the temperature does not ever drop below the glass
    transition temperature, though, there may be much less cracking.
-----

How Much Cracking Really?

Alcor has reported cracking in patients frozen to liquid nitrogen
temperature -- some cracks at all levels, from obvious surface
cracking to micro-cracks.  This has resulted in recommendations
to store patients at higher temperatures, perhaps in the vicinity
of -130 C.  Various Alcor people have gone to great pains to design
ingenious "cold rooms" for this purpose, and Cryonics Institute
has done some investigation of possible cryostat design for this
purpose.

However, the Cryonics Institute experiments with sheep heads, frozen
to liquid nitrogen temperature and later thawed, have *not* shown
cracking at the level of naked-eye inspection, either on the skin
surfaces or on the brain surfaces (visible through a window cut
in the skull).  Furthermore, as reported here many months ago,
in several cases we got good reperfusion, not showing the evidence
of leaks or broken blood vessels that would be expected if there were
any important cracking.

Recently, according to Dr. Hal Sternberg, BioTime has gotten consistently
good results with hamsters, using new perfusate formulations.  They
also get good reperfusion, after warming from liquid nitrogen
temperature, with no evidence of cracking at any level, including
examination with the light microscope.

Storage at higher temperature might still be desirable, and might
also save money.  But the importance of doing this to avoid cracking
is not at all clear, in light of the CI and BioTime results.

If we can get full details of the Alcor procedures that resulted in
the cracking, perhaps some of this can be clarified.
                                    R.E.
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