Protein and nucleic acid content in the aging human brain.

Author(s): Naber D, Dahnke HG

Publication: Neuropathol Appl Neurobiol, 1979, Vol. 5, Page 17-24

PubMed ID: 431765 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to investigate the effects of cold ischemia time (0-30 h) following a PMI of 6 h on protein and nucleic acid content of different brain regions (frontal cortex, white matter, cerebellum, thalamus, and caudate nucleus). Of note, two cases subjected to a PMI of 6 h were analyzed. Brains were then either snap-frozen or kept at 16 degrees C for 0-30 additional hours prior to freezing.

   Summary of Findings:

   No effect of cold ischemia on protein, DNA or RNA content was found in the first 25 hours postmortem. In the frontal cortex, at 36 hours post-mortem a reduction in protein (to 88% of levels observed with a PMI of 6 h; p<0.001) , RNA (93% of 6 h; p<0.05) and DNA (90% of 6 h; p<0.02) were observed. In the caudate nucleus, only protein (93% of 6 h; p<0.02) levels declined. In the thalamus, RNA declined to 80% of 6 h levels (p<0.005) by 36 h of cold ischemia, but no change in protein or DNA levels was observed. In white matter or cerebellum no change in protein, RNA, or DNA levels was observed. The authors concluded that stability of protein and nucleic acid in the brain post-mortem is dependent on brain region examined.

   Biospecimens

   • Tissue - Brain

   Preservative Types

   • Frozen

   Diagnoses:

   • Not specified
   • Autopsy

   Platform:

   Analyte	Technology Platform
   Protein	Lowry protein assay
   RNA	Spectrophotometry
   DNA	Colorimetric assay

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Acquisition	Biospecimen location	Frontal cortex White matter Cerebellum Thalamus Caudate nucleus
   Preaquisition	Postmortem interval	6 h
   Biospecimen Acquisition	Cold ischemia time	0 h at 16 degrees C following 6 h PMI 4 h at 16 degrees C following 6 h PMI 9 h at 16 degrees C following 6 h PMI 14 h at 16 degrees C following 6 h PMI 19 h at 16 degrees C following 6 h PMI 24 h at 16 degrees C following 6 h PMI 30 h at 16 degrees C following 6 h PMI

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2. Study Purpose

   The purpose of this study was to investigate the effects of patient age on postmortem protein and nucleic acid content of different brain regions (frontal cortex, white matter, putamen, cerebellum, thalamus, and caudate nucleus).

   Summary of Findings:

   Protein content decreased progressively with patient age (30-90 years) in all regions of the brain examined, although correlation the strength ranged from weak to modest. The largest decrease was observed in the thalamus, which displayed a 15% reduction (30 y compared to 90 y; r = 0.446) followed by the cerebellum (13% reduction; r = 0.545), caudate nucleus (9% reduction; r = 0.427), putamen (8% reduction; r = 0.402), white matter (7% reduction; r = 0.376) and the frontal cortex (5% reduction; r = 0.392). Age dependent changes in RNA or DNA content were not observed. The yield of RNA and DNA and the ratio of RNA:DNA was dependent on the brain region examined. Frontal cortex contained the highest RNA:DNA ration (1.78) followed by thalamus (1.27), caudate nucleus (1.12), white matter (0.83) and cerebellum (0.30). The authors conclude, protein but not nucleic acid content is decreased by age in a brain region dependent manner.

   Biospecimens

   • Tissue - Brain

   Preservative Types

   • Frozen

   Diagnoses:

   • Autopsy
   • Not specified

   Platform:

   Analyte	Technology Platform
   RNA	Spectrophotometry
   Protein	Lowry protein assay
   DNA	Colorimetric assay

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Acquisition	Biospecimen location	Frontal cortex Putamen White matter Cerebellum Thalamus Caudate nucleus
   Preaquisition	Patient age	30-90 y

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