. Adventures in radioisotope research;. Radioactive tracers; Radiobiology. 866 ADVENTURES IN RADIOISOTOPE RESEARCH haemins of guinea pigs, rats and rabbits exposed to 500 r, and in some cases up to 1400 r, and killed 5 to 66 hours after the injection of radio- iron (Hevesy and Bonnichsen, 1955; Bonnichsen and Hevesy, 1955). The results of these experiments are seen in Fig. 10. ^^Fe incorporation into haemoglobin and myoglobin alone is interfered with by exposure. 400r 2 3 4 5 Time after injecfion (days) Fig. 9. Uptake of ^®Fe in circulating blood of rats ("August" strain) injected su
. Adventures in radioisotope research;. Radioactive tracers; Radiobiology. 866 ADVENTURES IN RADIOISOTOPE RESEARCH haemins of guinea pigs, rats and rabbits exposed to 500 r, and in some cases up to 1400 r, and killed 5 to 66 hours after the injection of radio- iron (Hevesy and Bonnichsen, 1955; Bonnichsen and Hevesy, 1955). The results of these experiments are seen in Fig. 10. ^^Fe incorporation into haemoglobin and myoglobin alone is interfered with by exposure. 400r 2 3 4 5 Time after injecfion (days) Fig. 9. Uptake of ^®Fe in circulating blood of rats ("August" strain) injected subcutaneously with ferric chloride in citrate buffer 48 hours after irradiation wich various doses of 250 kVp X-rays. to radiation. Incorporation of ^^Fe into all other haemins investigated is not depressed; it is even enhanced. As after irradiation the number of marrow cells, the chief competitors for ^^Fe, get strongly reduced, more ^^Fe takes its way into the cells of the liver and other organs. Doses up to 100 r do not disturb clearance of ^^Fe in man (Loeffler, Collins and Hyman, 1953), but a dose of 800 r was found to decrease markedly the clearance of ^^Fe in the rabbit (Hevesy and Dal Santo, 1954). The above findings suggest the explanation that interference with haemoglobin formation is due to the radiation sensitivity of marrow cells. Radiation produces mitotic arrest in the latter, new-formation of erythropoietic cells is interfered with and, if larger doses are applied, cell destruction independent of mitotic processes may take place as Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Hevesy, Georg von, 1885-1966. New York, Pergamon Press
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