The artificial kidney and ion-exchange resins as possible methods of removing radioelements from the body.

Abstract

The classic studies of Aub, Evans et al. (1) in 1938 in radioelement removal demonstrated that the renal clearance for radium was less than 1 per cent in twenty-four hours. This finding suggested the possibility that direct radioelement removal from the blood might prove to be an effective way of eliminating radioelements. Both the artificial kidney (2) and ion-exchange resins (3) afford means for radioelement removal, as well as providing an opportunity for extension of the work by Hastings and Huggins (4) on the mobilization of calcium in the circulating body fluids. Preliminary in vitro experiments were performed to determine some of the parameters necessary to evaluate the feasibility of using either approach. The first experiments were carried out on a simulated artificial kidney. Stable calcium, calcium 45, and ethylenediaminetetraacetic acid were readily dialyzable under conditions similar to those in the artificial kidney (calcium being omitted for the purpose of the present experiments) (5). In later experiments solutions of strontium 85 and calcium 45 were passed directly through ion-exchange columns to determine the effectiveness of a synthetic cation exchange resin in removing these radioelements. Quantitative removal of strontium 85 and calcium 45 was obtained with the resin on a sodium cycle. Quantitative removal of these elements was also obtained with the resin on a calcium cycle. The advantages of the ion-exchange column over the artificial kidney are its simplicity, its potentialities for more widespread use, and its greater selectivity for polyvalent cations over divalent and monovalent cations. Biological Results: Radioelement removal has been attempted in dogs one hour, three days, seven days, and ten days after the intravenous injection of radiocalcium and radiostronium (see Table I). The first dog (CK-121) was kept on the artificial kidney for six hours, during which time 41 per cent of the radiocalcium was dialyzed into the bath, while approximately 1 per cent of the estimated total skeletal calcium content was removed. Radioelement removal has been carried out in three dogs by circulating the blood through an ion-exchange column. Forty and 33 per cent of the radiocalcium was removed after three and seven hours respectively, on the column. The second dog (CK-123) apparently died from hypocalcemia after three hours since the rate of calcium removal was high. By, reduction of the rate of blood flow through the resin column, the third dog was satisfactorily maintained seven hours. Strontium 89 was given three days and strontium 85 and calcium 45 were given one hour prior to placing the animal (CK-127) on the ion-exchange column. One week later the experiment was repeated (see Table I).