H. Frank, S. Gray
Oct 1, 1953
Citations
3
Influential Citations
46
Citations
Quality indicators
Journal
The Journal of clinical investigation
Abstract
Radioactive chromium has been found to tag red blood cells and plasma proteins (1). The anionic form, Na2Cr5104, labels the red blood cells, while the cationic hexavalent chromic chloride is firmly bound by the plasma proteins and is not taken up by the red cells. The affinity of the erythrocytes for sodium chromate has been used to measure the circulating red cell mass in man (2, 3). Radioactive chromic chloride is rapidly bound by the plasma proteins both in vivo and in vitro, and the binding appears to be relatively stable (1). The utilization of radioactive chromic chloride in the determination of plasma volume was suggested by the observation that 98 per cent or more of the chromic chloride is bound immediately by the plasma proteins when injected intravenously into humans. Once the chromic chloride is bound to the plasma proteins, it can leave the circulation only at the slow rate at which the proteins leave it. The dilution of this tracer substance in the circulation after intravenous administration was, therefore, used to measure the plasma volume in man. The plasma volume determination using radioactive chromic chloride presents a simple, accurate, and rapid technique, by which a stable,, non-toxic chemical solution can be injected directly, obviating the necessity of tagging albumin or other proteins in vitro. Determinations can safely be performed repeatedly and in rapid succession. Self-absorption corrections are not necessary. Liquid phase gamma ray counting permits the measurement of the plasma volume within a few hours. The plasma volumes of twenty-six normal adults have been determined by this method. In some of the subjects, a second determination has been done days to weeks later. The method was further tested by measuring the plasma volume before and after transfusion or hemorrhage of a known vol-