Density, fat, water and solids in freshly isolated tissues

Abstract

Once the initial density, D₁, is noted, a single piece of freshly isolated mammalian tissue is analyzed for water and fat. Knowing the densities of water and fat, the tissue's fat-free density, D₂, and the dry, fat-free density, D₃, can be computed. Among the various types of soft tissues, since D3 is similar, a simple relationship is shown to exist between the fat-free water content and the corresponding density. The biological extremes in a water:fat:protein system thus operate in such a way that the quantity of fat can be predicted from an equation containing three variables, i.e. the initial weight and density of a tissue and its quantity of water. This is of interest in human body composition and also to those who desire to make a sequence of determinations on a single piece of tissue without having to submit a portion thereof to direct analysis of fat, e.g. to express tissue electrolytes and water content on the fat-free basis. Submitted on June 15, 1959