X-Message-Number: 7635
Date: Tue, 4 Feb 1997 02:51:23 -0500 (EST)
Subject: Rat hearts Friday Jan. 31


Following my (Robert Ettinger's) remarks, this post will consist of a summary
by Andy Zawacki of the recent rat heart trials.
Charles Platt has reported on Sunday's demonstrations with 4 rat hearts at
Alcor by Olga Visser. (None of the 4 recovered after liquid nitrogen
immersion.) Charles was not present at her work Thursday and Friday with 8
other hearts. Two of these did revive and beat, although not with a full
normal beat, the third better than the fourth. There were several witnesses,
including Cryonics Institute's Andy Zawacki and Sally Bazan, who watched
closely. Andy was official note taker on Friday. Chief experimenter was Olga
Visser, second Hugh Hixon.
I was present at some of the work on each day, including most of the work on
Sunday, but did not happen to be present for the beating hearts on Friday.
But if Andy and Sally (in addition to Hugh, Fred Chamberlain, Linda
Chamberlain, Tanya Jones, and the other Alcor people) say they beat, you can
bet they beat. (And I did personally see hearts beat in September.)

Why such a low percentage of success? The work is demanding, with many
sensitive variables; Mrs. Visser is working on the borderline of feasibility,
and reducing procedures to a check-list of mechanical operations (like an
auto assembly line or an airplane take-off) is very difficult. Rat hearts are
small, and in this context fragile. Chemicals vary in quality, over time and
from different suppliers or even different batches. (Specifically, in this
instance, we found that several attempts were made with a defective or
contaminated batch of CPA.) It isn't easy to be sure of all the reasons for a
success or all the reasons for a failure.

Why did some of the short-time immersions succeed and all four of the Alcor
many-minute immersions fail? In one or two of these cases, specific reasons
were noted, unrelated to time of immersion. Beyond that, many possible
reasons; in the longer time immersions, several other variables had to be
changed also, e.g. the kind of container and manner of handling. Mrs. Visser,
because of equipment limitations, has only tried a few longer-time immersions
in South Africa, and succeeded with one of 45 minutes. 

Except in terms of short term psychology or public relations, nothing has
changed. Mrs. Visser's minimum achievement stands--she is the first person
ever to revive beating rat hearts (or any mammalian hearts) from liquid
nitrogen temperature. It remains unknown how much of this technology, if any,
will prove transferable to larger organs, different organs, and different
species. Work still remains to be done to make even the rat heart work easily
replicable. But the Cryonics Institute and the Immortalist Society and Alcor
and Mrs. Visser's team and collaborators, along with many others whom she has
stimulated, are pressing ahead. We cannot predict the nature or timing of any
dramatic breakthroughs applicable to cryonics patients, but we will certainly
advance in the years immediately ahead.      

CI and IS will be making reports, at appropriate times, to our members and
donors and the public as to our activities and funding and results.

R. C. W. Ettinger
Cryonics Institute
Immortalist Society
Report of Andy Zawacki, slightly edited: 


Rat heart #3 of the day:

The percentage of cryoprotectant was changed because prior attempts were

Once the hearts were perfused, they were left connected to the cannula on the
Langendorff system. The heart was covered in a shroud of cotton that was
secured to the cannula above the aorta. The cotton shroud was then soaked
with cold cryoprotectant. The flow of cryoprotectant was then turned off. A
container of liquid nitrogen was brought up under the heart and slowly moved
up to the apex of the heart and held there for 30 seconds. The container of
liquid nitrogen was then raised up to cover the rest of the heart and held
for 30 seconds longer. 

Though there was some concern that the heart was not fully immersed in liquid
nitrogen for the final 30 seconds, it appeared to me, considering the way
liquid nitrogen boils, that it was covered. [And Andy has a lot of experience
in viewing things in liquid nitrogen under a variety of conditions. --R.E.]

The liquid nitrogen was then removed and a container of cold perfusate was
brought up under the heart to the point of fully covering the heart, and it
was left in place for a period of time long enough to thaw the heart. The
shroud was then removed and reperfusion started.There were no visible cracks,
though there were some discolored spots.

After the heart was reperfused and warm life-support fluid had been
circulating through it, the left and right atria began to contract. The
contractions strengthened and kept a steady rhythm. The cardiac monitor was
connected to the heart and it showed a steady rhythm of ventricle
contractions. To the eye, the ventricle contractions were only visible around
the top of the heart, though from time to time it looked as though the sides
of the heart tried to contract also. The ECG signals and the rhythmic
contractions continued for an hour and five minutes, at which time the
experiment was terminated.

Rat heart #4 of the day:

The cooling and perfusion procedures were the same as for heart number 3,
though the perfusion time was longer. The shroud around the heart was
prepared and put on in the same way. The liquid nitrogen was brought up under
the rat heart to cover the apex and held there for 30 seconds the same as in
heart number 3. The liquid nitrogen was then moved up to cover the heart well
above the aorta and held there for 30-35 seconds. 

The flow of perfusate was accidentally left on during freezing and it was
then realized that there would be cracking problems. Thawing the heart was
done the same as with the third heart. There was a crack noted in the side of
the heart. The reperfusion and rewarming was accelerated to try to minimize
the damage from the crack. The heart regained rhythmic contractions in the
left and right atrium but only an occasional beep on the monitor for possible
ventricle contraction. The experiment was terminated after around 25 minutes
when the condition of the heart did not improve. 

Andrew F. Zawacki
Cryonics Institute

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=7635