Post-freeze-thaw viabilities of spleen slices by measurement of nucleic acid and protein syntheses

Unprotected cells deteriorate further in the 3 hrs post-thaw. Protection by a cryophylactic agent is partly explained by the cells' ability to return to reasonable DNA-dependent functions after return to normal body temperature, in the presence of oxygen and nutrients. Bacteria show a remarkable stimulation of post-thaw functions compared to mammalian cells. Early recovery is seen in high levels of lipid and glycoprotein syntheses. Oxygen consumption is much more affected by cold than is CO 2 release, reflecting specifically located intracellular damage. The fact that different tracers produced conflicting patterns is unexplained, but it is conjectured that glucose to protein is a separate mechanism compared to simple incorporation of labeled leucine. Similarly, incorporation of the sugar into the RNA nucleotides represent a different facet from base incorporation. The over-all patterns suggest the possibility that DNA that is capable of repair (by nucleases and polymerases) is the crucial factor in recovery from freeze injury, in that the other biosynthetic functions are DNA-dependent.