X-Message-Number: 2254
From: 
Subject: CRYONICS:  Audrey Smith's Frozen Rats
Date: Sat, 15 May 93 21:35:04 PDT

	While doing research for my independent project, I found 
some interesting articles in Audrey Smith's _Biological Effects of 
Freezing and Supercooling_  I thought you may find them 
interesting.  If anyone knows of more recent studies which contain 
similar results, please let me know.  

	"We found, in collaboration with animal psychologists, that 
rats which had been trained to solve problems of finding food in 
mazes showed no appreciable loss of memory after cooling to a 
body temperature just above the freezing point (Andjus, 
Knopfelmacher, Russell and Smith, 1955 and 1956).  The heads of 
the animals were packed in ice and there was no possibility that 
the brain could have remained warmer than the colon.  Activity of 
the cerebral cortex, as judged by electro encephalograms, ceases at 
about +18.degree C in the rat, so that cerebral activity must have 
been arrested for 1-2 hr. in all the animals tested.  After 
reanimation they were nevertheless, capable of acting on previous 
experience.  This result was not consistent with the theory that 
memory depends upon a continuous passage of nerve impulses 
through actively metabolizing neurones in the brain (Andjus, 
Knopfelmacher, Russell and Smith, 1955 and 1956).  Although 
behaviour and general health returned to normal soon after 
reanimation from 0.degree C, fertility and sex drive were 
lost for about 2-4 weeks and reduced until about 8 weeks after 
male and female rats had been cooled to 0.degree C and 
reanimated for the first time (Goldzveig and Smith 1956a)."  
(quoted from Smith, Audrey; _Biological Effects of Freezing and 
Supercooling_, The Williams and Wilkins Company: Baltimore, 
1961, pp 316-317)

	Dr. Smith also appears to have recognized the use of low 
temperatures for long term storage/revivification of mammals.  
	
	"So far no technique has been evolved for perfusing 
individual  organs or the whole mammal with glycerol and 
removing it without damage.  If this could be done it might be 
possible to cool the intact mamal to and resuscitate it from 
temperatures as low as -70.degree C.  Long term storage of frozen 
mammals might then be considered.  It must be emphasized that 
there is no prospect of accomplishing this in the near 
future."(quoted from Smith, Audrey; _Biological Effects of Freezing 
and Supercooling_, The Williams and Wilkins Company: 
Baltimore, 1961, p 363)


She also describes experiments that were done on the 
viability of nerve tissue.

 	Decapsulated rat ganglia together with their unsheathed 
nerves which had been treated with 15 per cent glycerol in Krebs' 
solution and cooled slowly to -79.degree C recovered after thawing.  
	In the first of the two cooling methods referred to in the quote, the 
cells were cooled in liquid glycerol medium; in the second method, 
the cells were immersed in glycerol solution, then frozen in open 
air on a glass dumb-bell.
 
	"Storage at -76.degree for 24 hr. had little harmful effect on 
ganglia which had been cooled in the presence of 15 per cent 
glycerol by either of the two slower [cooling] methods.  The action 
potentials recorded from the pre- and post-ganglionic nerves and 
the action potentials which had been transmitted through the 
ganglion were unaltered in amplitude and duration.  There was no 
impairment of the capacity to transmit a rapid succession of 
impulses across the ganglionic synapses.  Preparations which had 
been kept at -76.degree C for longer than 1 day did not, however, 
recover completely as judged by diminution of the electrical 
responses; action potentials of reduced amplitude were obtained 
from a preparation which had been kept for 21 days at -76.degree 
C (Pascoe, 1957)"(quoted from Smith, Audrey; _Biological Effects of 
Freezing and Supercooling_, The Williams and Wilkins Company: 
Baltimore, 1961, p 239)

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