Enzyme activities in relation to pH and lactate in postmortem brain in Alzheimer-type and other dementias.

Author(s): Yates CM, Butterworth J, Tennant MC, Gordon A

Publication: J Neurochem, 1990, Vol. 55, Page 1624-30

PubMed ID: 2213015 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to examine the effect of rapidity of death on pH, lactate concentrations, and the activities of 4 neuronal enzymes in the frontal cortex and caudate nucleus.

   Summary of Findings:

   Rapidity of death significantly affected lactate, pH, phosphate-acivated glutaminase (PAG) and glutamic acid decarboxylase (GAD) levels in both the frontal cortex and caudate nucleus of brain specimens. Those specimens procured following a prolonged agonal state (identified by the authors as several days to weeks) resulted in higher lactate levels (by 36-38%), and lower pH (by 3%), PAG (by 57-70%), and GAD (by 23-42 %) levels compared to specimens from patients that experienced a sudden death. Pyruvate dehydrogenase (PDH) and succinic dehydrogenase (SDH) levels were not significantly affected by rapidity of death. Although postmortem interval was reported, it was not investigated as a confounding variable. GAD and PAG activities were correlated to pH (r=0.80, p<0.001; r=0.86, p<0.001, respectively) and lactate concentrations (-0.80, p<0.001; -0.83, P<0.001, respectively) in the caudate nucleus. In the frontal cortex, PAG alone correlated with pH and lactate concentrations (r 0.73, p<0.001; r=-0.62, p<0.00, respectively1). The authors conclude that slow death increases lactic acid concentrations resulting in lower brain pH and decreased GAD and PAG activities but does not impact PDH or SDH activities.

   Biospecimens

   • Tissue - Brain

   Preservative Types

   • Frozen

   Diagnoses:

   • Autopsy
   • Cardiovascular Disease
   • Not specified

   Platform:

   Analyte	Technology Platform
   Small molecule	pH
   Small molecule	Enzyme assay
   Protein	Enzyme assay

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Preaquisition	Rapidity of death	Sudden death Prolonged illness
   Biospecimen Acquisition	Biospecimen location	Frontal cortex Caudate nucleus

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