The Anemia of Infection. V. Fate of Injected Radioactive Iron in the Presence of Inflammation 1

Abstract

Since hypoferremia is so consistently associated with the anemia of infection (1), and since injected iron appears to be diverted from the plasma in infection (1, 2), it seemed desirable to determine the fate of the diverted iron.In this study, radioactive iron was injected intravenously into normal rats and in rats with acute inflammation. The blood and tissues were then analyzed after a period of time for radioactivity. Preliminary studies were made in which only the blood and liver were analyzed in order to determine the appropriate amount of iron to employ. Radioactive iron was also injected intravenously into dogs, and analyses were carried out on a number of tissues, including the exudates. METHODSThe radioactive iron used in these studies was injected as ferric chloride in physiological saline. For the rats, the concentration was adjusted so that about 0.2 ml. was injected for each 100 grams body weight. In all the rats the same tuberculin syringe was employed for this purpose. In order to be certain that the solution did not enter subcutaneously, the vein on the lateral aspect of the tail was exposed under nembutal anesthesia and the solution was injected intravenously. In one experiment Fe was injected intraperitoneally.Inflammation was produced by the intramuscular injection of 0.5 ml. of turpentine. Robscheit-Robbins and Wlhipple (3) have shown that the resulting sterile abscess can be compared with a bacterial abscess. In some animals, 0.5 ml. of a mixed culture of S. aureus and E. coli was injected intramuscularly. Injections of bacteria or turpentine were made about 2 hours before Fe was administered.The methods for preparing and electroplating the Fe from the biological samples have been described elsewhere (4). Blood volume was estimated by assuming that the normal mammal possesses 80 ml. blood per kgm. body weight. Hemoglobin was determined in a representative sample of the tissue to be analyzed for radio-

Radioactive Iron Metabolism and Erythrocyte Survival Studies of the Mechanism of the Anemia Associated with Rheumatoid Arthritis1

“…Previous studies of iron metabolism in patients with chronic inflammation, including patients with rheumatoid arthritis, have shown diminished red cell utilization (26)(27)(28), and increased tissue deposition of injected radioiron (29). These studies differed from the present one in that the injected radioiron was not bound to transferrin, and the amounts of carrier iron injected often exceeded the total iron-binding capacity of the plasma.…”

Chemical, Clinical, and Immunological Studies on the Products of Human Plasma Fractionation. Xxxviii. Serum Iron Transport. Measurement of Iron-Binding Capacity of Serum in Man 1

“…Depression of the per cent saturation occurs in iron deficiency and in infections. It seems reasonable to explain the former on the basis of depletion of body iron and the latter on an increased affinity of tissue storage depots for iron (15).…”

The Anemia of Infection. Xiv. Response to Massive Doses of Intravenously Administered Saccharated Oxide of Iron 1

“…Indeed, experiments by Menkin (17,18) in the rabbit have indicated that iron accumulates in the inflamed area where, it is postulated, a beneficial function may be served. Our own studies in experimental animals (19), however, would suggest that the amount of iron so diverted is by no means adequate to account for the hypoferremia.…”