Rate of Penetration of Ions into Erythrocytes

Abstract

I n the study of the permeability of phase boundaries to ions usually an inorganic salt, the ions of which are to be investigated, is added to one of the phases and the time is measured after which a certain concentration of the salt can be ascertained in the other phase. The result of such experiments indicates, however, not the resistance which one kind of ions encounters when passing the phase boundary, but the resultant of the hindrance of both ions of the salt or, if a cation, for example sodium, present in one phase interchanges with potassium, for example, present in the other phase, it indicates the resultant of the hindrance of the passage of the sodium and of the passage of the potassium ion through the phase boundary. If one of the two ions encounters a great resistance when passing the membrane it will compel the other ion to move slowly as well.1 Furthermore, this method implies that the ion can accumulate in the second phase. The hindrance which an ion encounters when passing the phase boundary can be measured by measuring the rate a t which labelled and non-labelled ions interchange through the phase boundary. When one phase contains W a ions, the other phase besides 23Na ions also 24Na ions of negligible weight, we obtain by determining the rate a t which 24Na penetrates into the second phase a correct measure of the hindrance which sodium ions encounter when passing the phase boundary and, thus, a cor-The influence which the anions exercise on the rate of penetration of the ~~ cations is discussed on page 220. 13 -413286. d c t a phys. Scandimav. Vol. 3.

Blood Volume Determination in the Human With Red Cells Containing Radioactive Phosphorus (P32) and With Pure Human Albumin 1

“…The, error of the hematocrit due to adherence of plasma to the packed red blood cells has been studied and is found to be about 2 to 3 per cent (16,19,20,43). Now if the plasma adherent to the red blood cells in the aliquot of the injected blood has the same activity as the red blood cells, there is no error in determination of C1 in Formula 1.…”

“…Hahn and Hevesy (19) offer further evidence that the uptake of phosphorus by the red blood cells is actually due to metabolic activity by demonstrating that the addition of KCN to the system reduces markedly the formation of organic phosphorus compounds; that the uptake of phosphorus is independent of concentration of phos- phorus in the plasma; and that hemolysate at 370 takes up p32, though at a slower rate than intact red blood cells. In general, then, it may be said that the phosphorus enters the red blood cells in a large part by a process of organic synthesis (i.e., metabolic activity) rather than simple diffusion according to concentration gradients and that the metabolic process primarily concerned is glycolysis during which organic phosphorus esters are synthesized.…”

“…The error due to loss of pS2 from the cells to the plasma is in the order of 1 to 2 per cent (1,17,19,20,37). This will also render the error in determination of blood volume positive because the counts per cc.…”

“…No significant change in red cell volume was observed by either method. (42), and Hahn and Hevesy (19) have shown that there is little or no uptake of phosphorus by the red blood cells at 00 C., whereas the uptake at 37°is considerable.…”

“…The disadvantages lie in the short period (one hour) during which the red cells maintain constant radioactivity. Considerable data obtained by the two phosphorus methods have been reported (1,(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26).…”