Ii. The Simultaneous Measurement of Exchangeable Body Sodium and Potassium Utilizing Ion Exchange Chromatography

Abstract

A technique based on the isotope dilution principle for the measurement of exchangeable body sodium in man has been devised and evaluated by Forbes and Perley (1) and Miller and Wilson (2), and a similar technique for exchangeable body potassium has been developed by Corsa, Olney, Steenburg, Ball, and Moore (3). Once the individual techniques for the measurement of exchangeable body sodium and potassium had been devised, the desirability of carrying out these measurements simultaneously became apparent because of the important biochemical inter-relationships that have been pointed out between these two alkali metals (4-6). Since the metabolic state of a patient may vary considerably during even a relatively short period, single exchangeable body sodium and potassium measurements carried out several days apart are not a satisfactory substitute for simultaneous measurements.Such simultaneous measurements, based on the isotope dilution principle, require at present the separation of sodium from potassium prior to the radioactivity determinations. James, Brooks, Edelman, Olney, and Moore (7) have described a technique for these measurements in which classical chemical methods are used to separate the electrolytes. In the present study we have made use of ion exchange chromatography (8) for the separation. At the outset, our primary concern has been with the reproducibility of this technique for the simultaneous measurements of exchangeable body sodium and potassium in normal young adults."Exchangeability" of sodium and potassium Twenty-four hours has been chosen by previous investigators (1-3, 7) as a satisfactory and convenient equilibration period. Estimated values in man indicate that approximately 82 per cent (1) of the total body sodium and 90 to 95 per cent of the total body potassium (3) are exchangeable in twenty-four hours. These measurements must be considered as preliminary since their accuracy depends on an exact knowledge of rates of electrolyte exchange in all areas of the body, data which are not yet completely available in man. In the case of sodium, bone and brain constitute areas of slow exchange (1, 2, 9), while in the case of potassium, red cell, brain, and bone exchange less rapidly than do other regions of the body (3, 10). Even though the measurement of exchangeable sodium and potassium of the body does not correspond to the total body content of these elements, it does furnish an index of total body sodium and potassium which probably varies directly with total body electrolyte content. EXPERIMENTAL METHOD a) General outlineKnown amounts of radioactive sodium (Na) and of radioactive potassium (K0) are injected intravenously. After a twenty-four hour equilibration period, a blood sample is drawn and sodium and potassium radioactivity and concentration (i.e., specific activity) of the proteinfree serum supernatant are determined. We have described in detail in Part I (8) the use of a sulfonic acid cation exchange resin, Dowex 50, to effect the separation of Na" and KZ in order to measure their ...

Potassium depletion in heart failure and its relation to long-term treatment with diuretics: a review of the literature

“…Height was noted if it had been measured, and for each patient with heart failure it was noted whether the patient was oedematous and if he was taking diuretics alone or with potassium supplements. Details were collected of 345 healthy controls (Corsa et al, 1950;Aikawa et al, 1952;Deane and Smith, 1952;Arons, Vanderlinde and Solomon, 1954;Blainey et al, 1954;Moore et al, 1954;Wilson et al, 1954;Ikkos et al, 1955;Sagild, 1956;Ljunggren, Ikkos and Luft, 1957;Birkenfeld et al, 1958;Crookes, Bluhm and Muldowney, 1959;MacGillivray, Buchanan and Billewicz, 1960;Talso et al, 1960;Deuxchaisnes et al, 1961;Singh et al, 1969;Cox et al, 1971;Skrabal, Arnot and Joplin, 1973); and 333 patients with heart disease (Aikawa et al, 1952;Blainey et al, 1954;Moore et al, 1954;Wilson et al, 1954;Aikawa and Fitz, 1956;Birkenfeld et al, 1958;Deuxchaisnes et al, 1961;Olesen, 1964;Carroll, Gotterer and Altshuler, 1965;Flear et al, 1966;Olesen, 1968;Singh et al, 1969;White et al, 1969;Cox et al, 1971;Croxson et al, 1972;Davidson and Gillebrand, 1974;Olesen and Valentine, 1973).…”

An Improved Method for Simultaneous Determination of Exchangeable Body Sodium and Potassium

“…The coefficients of variation of the exchangeable body sodium and potassium measurements estimated from these seven cases are 3.2 per cent and 3.6 per cent, respectively. Thus differences of 9.0 per cent and 10.0 per cent, respectively, must exist between successive body sodium and potassium measurements to indicate a significant difference in these values by the criterion previously used (1) . 1O The coefficients of variation of the present method are somewhat higher than those obtained from similar measurements on a set of six subjects by the ion-exchange chromatographic method (1), 2.6 per cent for sodium and 2.0 per cent for potassium.…”

“…The introduction of a differential counting technique has considerably simplified and facilitated simultaneous measurements of body electrolytes as compared with the procedures previously described (1,10). SUMMARY An improved method for the simultaneous determination of exchangeable body sodium and potassium, utilizing a differential counting technique is described.…”

“…of blood were drawn and the serum separated by centrifugation. The amount of radioactivity lost in feces and sweat is insignificant in normal subjects (1). To measure the injected radioactivity, duplicate standard solutions of Na" (dilution 10: 250) were counted in triplicate for 10,000 counts in the scintillation counter and K" (dilution 1: 1000) standards were similarly assayed in the dip counter.…”

Radioactive Isotopes in Medicine: A Review

“…Total body water presents no problem since the half-life of 3H is 12.3 years and it is necessary merely to wait for the decay of the other isotopes, all of them with short half-lives, before counting the tritium in samples or to separate the water by some method. Separation of the others, since their half-lives are similar, must be done by chemical means (James, Brooks, Edelman, Olney, and Moore, 1954;Wittig and Raff, 1951;Munro, Renschler, and Wilson, 1958;Arons, Vanderlinde, and Solomon, 1954), by physical means (Tait and Williams, 1952;Robinson, Arons, and Solomon, 1955;Flear, Cawley, Quinton, and Cooke, 1958;Munro et al, 1958), or some convenient combination of both. A comparison of both techniques is given by Munro et al (1958).…”