Energy state and glycolysis in human cerebral edema

Abstract

✓ A new freeze-stop device using a liquid nitrogen reservoir and an automatic biopsy mechanism has been developed, suitable for rapid, sterile, and standardized sampling of cerebral tissue in man. In animal experiments a 200 mg piece of cerebral cortex was cooled from a room temperature of 18°C to −40°C within 7 sec which is twice as fast as when it was immersed in liquid N2. The method was then applied to metabolic tissue studies of perifocal edematous cortex from patients undergoing neurosurgery for intracranial tumors. Energy-rich phosphate compounds or parameters of the energy state were found to be less affected in this type of brain edema than the glycolytic activity which was markedly enhanced, indicated by lactic and pyruvic acid determinations. The tissue water content correlated closely with the lactic acid concentration, and very little with measurements of the energy state such as the energy charge potential or the adenosinetriphosphate-adenosinediphosphate (ATP/ADP) ratio. It is suggested that in perifocal brain edema increased levels of lactic acid are associated with mechanisms leading to an increased water uptake.