QUANTITATIVE DETERMINATION OF DNA IN PRESERVED BRAINS AND BRAIN SECTIONS¹

Abstract

Abstract— Existing methods for the colorimetric (diphenylamine) determination of DNA content of brain have been modified for preserved cerebral hemispheres. On the average, right and left hemispheres (rat and chicken) contained similar amounts of DNA and one hemisphere could serve as a control for the other. All comparisons have been made with the values obtained for frozen brains (‘controls’). Preservation in 10 % (v/v) buffered formalin for 1 month introduced significant differences for both neonatal and adult cerebral hemispheres. On the other hand, preservation in 75 % (v/v) aqueous ethanol for 1 month did not introduce any significant differences in any of these determinations. Embedding in paraffin and subsequent clarification (removal of paraffin) did not further affect the DNA values of cerebral hemispheres preserved in formalin. Consequently it was possible to determine DNA in histological sections at the desired planes or even in parts of the sections. Micro‐modifications have been devised to determine colorimetrically the total DNA content of small brains (e.g. tadpoles) or of small parts of larger brains, as low as 25 μg of DNA/sample.

Maternal Nutrient Storage and Efficiency in Production of Fetal Brain Tissue in Rats

“…It has been reported that during malnutrition the organism reduces the catabolism of essential amino acids to urea, and increases activation of amino acids, thus favor ing the incorporation of amino acids into proteins (reviews in 10, 11). Intestinal absorp tion of nutrients (for this reduced amount of food) also improves (14). These improvements may involve inducible enzymes.…”

“…The 'brain', as dissected, was cerebrum without cerebellum and olfactory lobes. DNA was determined by a modification of the diphenylaminc colorimetric method (14); protein was determined by a modification of the Lowry colori metric method (6).…”

Programmed Cell Death Enhances Uniformity in Rat Cerebral Hemispheres

“…At birth (0 days) or at weaning (30 days in our studies), representative numbers were decap itated; CH were immediately removed, weighed and stored at -1 0 °C for subsequent analysis. DNA was determined by modification of diphenylamine colorimetric methods [17]. Protein contents were determined by the method of Lowry et al [19].…”

The effects of glucocorticoids on thymidine kinase and nucleoside phosphotransferase during development of chicken embryo retina

“…Protein concentration was estimated as in [7] using bovine serum albumin as standard. DNA content of retinas was determined by a modification of the Burton procedure as in [8,9].…”