Strong ion difference: Questionable stewardship

Abstract

Strong ion difference: Questionable stewardshipA follow-up 1 to a recent discussion of urinary acidity 2,3 focused on Stewarts's theory of 'strong ion difference' (SID). [4][5][6] The comments of Vasileiadis et al 1 warrant a reevaluation of Stewart's approach. Here, it will be discussed (a) that the SID is unlikely to be an independent variable as claimed by Stewart, (b) that the calculation of [H + ] based on SID described by Stewart is hardly doable, even in simple electrolyte solutions, (c) that human metabolism provides an ongoing acid-base disturbance as an independent variable (normally excess H + accompanied by chloride), (d) that specific renal regulatory mechanisms indispensable to Stewart's concept, remain unknown, and (e) that studies of biological transmembrane cation transport have progressed to a level making serious opposition to the concept of active transport of H + meaningless.