Headline from the front page of the Saturday May 15,1999 issue of the Globe and Mail newspaper:
"Reviving an Extinct Species
Austrian Museum director Michael Archer examines an 1866 embryo of a Tasmanian Tiger, an extinct species that scientists hope to revive. Because the embryo was preserved in alcohol, its DNA remained intact. Scientists now hope to clone this embryo and others, thus bringing the species back to life."
The article continues on page 2, and states that geneticists are now saying that this proposed species revival is not a joke, and that it could be done. The relevance to cryonicists is that any attempt to provide a lower cost alternative to current liquid nitrogen suspension will have to involve dehydration. None of the methods of chemical preservation (formaldehyde, glutaraldehyde, etc) which involve storage in an aqueous medium truly prevent deterioration of tissue. Only methods which involve dehydration (alcohol storage, anhydrobiosis, etc) can have any hope of offering a viable alternative to low temperature storage. The following is a quote regarding glycerol treated bone marrow stored at dry ice temperatures from (Cryobiology 65-69 1970):
"Smears of all human bone marrow samples stored for 3 to 9 years at Dry
Ice temperatures revealed disruption of normal cellular architecture of
the bone marrow cells. Virtually all cells showed nuclear vacuolation,
pyknosis, and karyolysis. The only cells with intact architecture were
lymphocytes and cells of erythroid series. Many of these contained
nuclear vacuoles. In addition the smears contained numerous remnants of
cells which could not be recognized as to type. Differential counts
revealed that on the average only 5 to 10% of cells maintained distinct
nuclear outlines. These cells were predominantly of lymphoid and
erythroid series with occasional eosinophils and monocytes.
Similar changes were observed in samples of human and dog bone marrow
stored in liquid nitrogen for 1, 2, and 3 years. However, these changes
were found only in about 5 to 10% of cells regardless of the time of
storage. In an occasional smear, the proportion of damaged cells reached
as high as 20%. The changes in liquid nitrogen-stored bone marrow were
not confined to any specific cell types.
....
The observations reported in this paper indicate that very severe
changes have taken place in bone marrow stored for over 3 years in Dry
Ice. It has been previously shown that bone marrow cells stored under
identical conditions for periods of up to 1 year maintain their normal
morphology.
However changes became apparent by 2 years and were severe by 3."