Joseph B. Boatman

Effect of physical factors on radiosodium clearance from subcutaneous and intramuscular sites in animals.

Summary A study of the effect of physical factors on radiosodium clearance in dogs is reported. The average clearance rate in 25 control intramuscular injections was 59.4% activity remaining after 10 minutes. Decreases in intramuscular clearance rates were demonstrated with application of ice-salt mixtures, radiant heat and pressure cuffs. The average subcutaneous clearance rate in 10 control studies was 75.8% activity remaining in 10 minutes. This rate of clearance was increased with the addition of hyaluronidase. The clearance of radiosodium from a part does not appear as a straight line function when plotted and the calculation of per cent activity remaining per unit time is suggested as an expression for determination of clearance rates. The present study entirely supports the view of Kety that this technic is applicable to measure the effective circulation of a tissue and indicates the need for further study to quantitate the procedure for clinical application.

Changes in Adrenal and Pituitary Concentrations of I131 and P32 Following Thyroidectomy.

Summary 1. Seventy days after thyroidectomy the ability of various organs of young and adult male albino rats to concentrate radioiodine I131 and radiophosphorus P32 was determined and compared to control animals. 2. The pituitary and adrenals of the young rats showed a markedly increased 3-hour concentration of I131 and a decreased 3-hour concentration of P32, significantly different from the control animals. 3. Mature animals exhibited an increased 3-hour concentration of I131 in the pituitary, with no significant differences in the 3-hour concentration of P32 from levels seen in the control animals. 4. The deleterious effects of thyroidectomy in the young animals with a high rate of tissue phosphate utilization was evidenced by the sharply decreased P32 concentration in the organs of those animals. Explanation for the markedly increased I131 concentrations in pituitary and adrenal of young and adult thyroidectomized animals is not readily apparent.

TOXICITY OF RADIOIODINE AND RADIOPHOSPHORUS IN RATS IN DOSES COMPARABLE TO THOSE USED CLINICALLY

Summary and Conclusions 1. Radioactive phosphorus (P32) was administered by intubation to young male rats in doses equivalent to 4.6 mc. 7.0 mc and 11.6 mc for a 70 kg man. Similar radioiodine doses of I131 equivalent to 14.0 mc, 42, and 420 mc were given. All animals were sacrificed 6 weeks after dosing. 2. Except for a significant decrease in the testes body weight ratio and a moderate lymphopenia at the time of autopsy no growth curve, organ weight or histologic evidence of damage was discerned in the animals receiving P32. 3. Although no changes in weight gain or histologic evidence of organ damage was observed following the administration of I131, some variations in organ weight/body weight ratio were recorded. 4. In the doses here employed, which were comparable to those used clinically, no evidence of serious radiation damage was recorded.

Effect of Adrenalectomy and Dca On the Radioisotope Intramuscular Clearance and Distribution in the Rat

From the Addison H. Gibson Laboratory of the School of Medicine of the University of Pittsburgh. * Presented before the American Physiological Society, September 15, 1950. † This study was aided in part by a grant from the Sarah Mellon Scaife Foundation. 1 Desoxycorticosterone acetate (Percorten) in oil supplied through the courtesy of Ciba Pharmaceutical Products, Inc., Summit, New Jersey. 2 From the Oak Ridge National Laboratory, Oak Ridge, Tennessee. Recent studies by Kety (1, 2) and Elkin et al. (3) on the rate of removal or &dquo;clearance&dquo; of radiosodium from intramuscular sites of injection have demonstrated the technic to be a measurement of effective circulation of a tissue. It was later established that neither lymphatic drainage nor diffusion along intramuscular planes have a significant role in the clearance of the injected radiosodium (4). The radioisotope clearance has been shown to be altered by tourniquet application, exercise (2) and such physical factors as heat, cold and abdominal pressure (5). This method of measuring blood flow has been extended to quantitating circulation in liver (6), skin (5), and brain tissue (7). Other radioisotopes, radioiodine (I131) and radiophosphorus (P32), have been shown by Boatman (7) to be applicable in the determination of cerebral and muscle clearance. This study was undertaken to further quantitate the procedure and to investigate the effects of adrenalectomy and the administration of DCA and saline in the adrenalectomized state upon the peripheral circulation as measured by the intramuscular clearance of Na24 and I131 in the rat. The concentration of I131 in various organs in these altered states was also determined.