A Formula and Nomogram for the Estimation of the Osmotic Pressure of Colloids From the Albumin and Total Protein Concentrations of Human Blood Sera

Abstract

In connection with investigations to be reported subsequently the osmotic pressure of colloids and the albumin and total protein concentrations of 128 samples of human blood serum were determined. From these data, which cover a wide range of values, an empirical formula has been evolved which, it is believed, will enable the osmotic pressure to be more accurately estimated from the protein analyses of human sera than is the case with formulae now employed for this purpose (1,2

Studies of Iodoalbumin Metabolism. Ii. The Effects of Thyroid Hormone*

“…We are not aware of any direct determinations of capillary pressure in myxedema. The mean increase in plasma colloid osmotic pressure in myxedema in the patients of Experiment I computed from their plasma protein concentrations was only 15 per cent (32). Although the mean capillary pressure cannot be computed from the plasma colloid osmotic pressure without assumptions regarding interstitial fluid colloid osmotic pressure and tissue pressure (27), these considerations suggest that the changes in capillary pressure in myxedema, if any, are small, and are probably not the explanation for the marked increase in transcapillary passage of albumin.…”

The Osmotic Pressure of Proteins in Whole Serum 1

“…Beyond the statement that these measurements of total colloid osmotic pressure agree in general with those of other reliable investigators (7,14,15,17,20,23,24), comparisons on the basis of magnitude alone can not be profitable, since small variations depend so largely on details of technical procedure. The method employed is believed, for reasons stated above, to be soundly devised, and yields reproducible measurements.…”

A Clinical and Experimental Study of the Stability of Colloid Osmotic Pressure of Serum Protein

“…Various dilutions of normal dog serum were prepared by the addition of 0.9 per cent saline at pH 6 method of estimating concentration of protein gives a somewhat higher value than the Kjeldahl method it was found sufficiently accurate for comparative purposes.…”

“…However, in all of these reports, the pressure readings were taken at the end of twentyfour hours or longer, and probably do not represent the highest point on the pressure curve. Wells et al (6) have recently discussed the validity of determining the colloid osmotic pressure by a rapid method devised by them. They also presented data on hypoproteinemic sera which gave low specific pressures, and referred to the fact that the pressure in many cases after rising to some extent began to fall within a few hours.…”

“…They attempt to explain this by putrefactive change or molecular aggregation of serum protein (6,7). In the method reported here the possibility of contamination of the serum with bacteria has been excluded.…”