THE BEHAVIOR OF LIPIDS DURING AUTOLYSIS OF LIVER AND BRAIN

Nuclear size and cytochemical changes during autolysis in free gingival autograft epithelium

Karyometric and cytophotometric measurements of DNA and RNA have been evaluated in gingival graft epithelium. The study was conducted during the first 20 hours from the time of grafting when the graft epithelium undergoes a process of autolysis. Both basal cell and prickle cell layers were used. The results showed an increase in optical density for Feulgen-DNA according to the time of grafting. At the same time pentose nucleic acid (RNA) and nuclear size showed decreasing values. It was concluded that pycnosis was the usual course of nuclear autolysis in graft epithelium. In addition gingival graft epithelium was found to be an useful model for the study of cell autolysis in vivo.

Lipids of the nervous system during in vitro degeneration

The changes in the concentration of lipids during the in vitro degeneration of cat brain slices and sciatic nerve have been determined after incubation in bicarbonate buffer for periods of time from 1 to 14 days. In brain slices incubated for 14 days there was a great decrease in the concentration of total phospholipid with no change in the concentration of cerebroside or total cholesterol. Of the individual phospholipids, there was a decrease in the concentration of sphingomyelin and cephalin and no significant change in the concentration of lecithin. In sciatic nerve incubated for eight days, there was a significant decrease in the concentration of cephalin and a decrease of borderline significance in the concentration of total phospholipid. There was no significant change in the concentration of cerebroside, free or total cholesterol, sphingomyelin, or lecithin. Thus in tissue of the nervous system, there appears to be a phospholipid-splitting mechanism, possibly enzymatic in nature.