Muscular Dystrophy. Cation Concentrations in Residual Muscle

Abstract

Muscle samples of dystrophy patients and control subjects were obtained on biopsy. Samples were analyzed for water content and for Na and K concentration. Volume of the extracellular water was estimated from the rate of egress of Na from the tissue into glucose solution. The amount of blood contained in the samples was measured by means of Cr 51 labeled red blood cells. From these experimental figures the concentration of Na and K were calculated in the fiber water of the remaining muscle mass in the dystrophic tissue. K was reduced and Na increased in the residual muscle fibers, i. e. after allowing for fat and connective tissue replacement. Loss of K is compensated for by a corresponding increase in the Na concentration. Good correlation was found between the changes of cation concentrations mentioned on the one hand and the degree of involvement of the muscle on the other, provided the volume of the remaining fiber water was used as a measure of the latter.