The Tagging of Red Cells and Plasma Proteins With Radioactive Chromium 1

Abstract

Relatively few reports have appeared on the chromium content of biological material. Previous studies were devoted primarily to the analysis of plants and soils ( 1 ).In preparation for the present study, arc spectrography 3 was used to demonstrate the presence of trace amounts of chromium in human tissues, including the blood. Tissue analyses were performed on samples of normal human blood by means of a colorimetric method (2) with the finding of mean values of 20 y % for packed red cells and 14 y % for plasma.The present report is concerned with a new biological tracer, radioactive chromium (Cr51), which is bound by the red cells and plasma proteins. Both anionic hexavalent (Na2Cr51O4) and cationic trivalent (Cr51Cl3) states of the element have been studied.Cr51 is a soft X-ray emitter with a half-life of 26.5 days. It disintegrates by K capture with transmutation to vanadium and emission of Xrays of 4.92 Kev plus a few per cent of 0.237 Mev gamma rays (3).To prepare Cr51 from Cr50 in the pile with sufficiently high specific activity,'4 it was necessary to enrich ordinary chromic oxide (Cr2,O) electromagnetically. Naturally occurring chromium contains 4.49 %o Cr50; the enriched chromium, 41.2%o. This enriched mixture was then irradiated in the Oak Ridge pile for two months, at the end of which

The Use of Radioactive Chromium 51 as an Erythrocyte Tagging Agent for the Determination of Red Cell Survival in Vivo 12

“…Gray and Sterling (9,10) have demonstrated that a firm union between erythrocytes and chromium can be established in vitro with great rapidity and with no apparent damage to the exposed cells. These observations imply that radioactive chromium might serve admirably, not only as a tagging device for measuring circulating red cell volume as proposed by these authors, but as a basis for measuring red cell survival in vivo.…”

“…9 Note: this value does not include the small amount of free Cr'1 which was present in the injected plasma. The rate at which chromium combined with red cells when sodium chromate was added to whole ACD blood was dependent upon the temperature and pH of the mixture, as demonstrated in Figure 1 and Table III.…”

Chromium chloride increases insulin‐stimulated glucose uptake in the perfused rat hindlimb

“…Some researchers suggest that chromium (VI) is reduced to chromium (III) when ingested orally (26,51). In humans Earlier animal work has shown that when chromium (VI) is given intravenously or intratracheally, the plasma concentration levels drop at an accelerated rate compared to the red blood cell chromium concentrations (28,32,69). However, in this study (39), after cessation of supplementation, there was a very rapid decrease in the red blood cell chromium concentration, similar to the decrease seen in plasma chromium concentration.…”

The Carcinogenicity of Chromium

“…Oxidation oftrivalent chromium (or chromium metal) to the hexavalent form in organic matter seems unlikely (13). (13,16). Once in the cell, the hexavalent form is reduced to the trivalent.…”