The Use of Two Radioactive Isotopes of Iron in Tracer Studies of Erythrocytes 1

The in Vitro Preservation and Post-Transfusion Survival of Stored Blood 1

“…The specific radioactivity of the donor's and recipient's whole blood, erythrocytes, hemoglobin, and hemoglobin iron was determined with techniques similar to those described by one of us in previous papers (2,24), with some modifications (25). In these experiments we have used the radioactive isotope Fe55 (half life approximately 5 years) instead of the radioactive isotope Fe59 (half life 47 days).…”

“…The longer half life of Fe55 makes this isotope much more satisfactory than Fe59 for long-term cell tracing experiments. The radiations from Fe55 are low energy x-rays and have necessitated the use of a beryllium window counting tube (25) instead of the thin mica window tube previously used. The preparation of the samples of blood for determination of radioactive con-tent by acid digestion, neutralization, and precipitation of iron is identical with those previously described (24) with the exception that the iron in the present series of experiments was precipitated as ferric hydroxide instead of ferrous sulfide.…”

“…The iron was electrolytically deposited in a uniform, thin layer on copper discs as previously described (24,25), but the plating process was carried out from a ferric rather than a ferrous solution. This required a longer period of electroplating than was the case when a ferrous solution was employed but was satisfactory for quantitative removal of the iron.…”

Biological Hazards and Toxicity of Radioactive Isotopes

“…Isotopes in a borderline class include Fe55, Fe59, Ca 5, and the long-lived isotopes Na22 and C136; with these, somewhat more caution is indicated than with the shortest-lived radioelements. As examples of actual practice, Na22 has been used in normal subjects (18) in such a way as to yield somewhat less than 1 rep total integrated dosage (90 uc in man); Fe55 and Fe59 have been used in normal blood donors (19) in such dosage as to yield a maximum of 0.1 rep per week in blood. p32 has been given to human subjects to establish its turnover in tumors, including operable tumors.…”

The Effect of Varying Temperatures on the Post-Transfusion Survival of Whole Blood During Depot Storage and After Transportation by Land and Air 1

“…Since the problem of successful transportation involved the determination of adequate refrigeration range, experiments were conducted in which bloods were transported by air both under controlled and uncontrolled refrigeration. The method of measuring post-transfusion survival by means of 2 isotopes of radioactive iron has been previously described (9,10). DEPOT …”