Two methods of determining the survival of stored red cells are described: one using a double label and one using a single label. It is not suggested that one is superior, but rather both methods are presented in the hope that the personnel of laboratories engaged in determining the effectiveness of anticoagulant-preservation will follow one of the protocols presented. Were this to occur, many of the interlaboratory variations that have decreased the value of data from red cell survival studies would be decreased.

The functional properties of formed elements of whole blood were studied following irradiation doses of 500 to 20,000 rads. Irradiated lymphocytes retained only 1.5 per cent of their 3H thymidine uptake after a 5,000-rad exposure and none after 7,500 rads. Red blood cells stored for 21 days and then irradiated with 5,000 rads had the same survival as nonirradiated controls. In contrast, 5,000 rads reduced platelet yields. However, transfused irradiated platelets produced the expected increases in platelet counts and controlled hemostasis in thrombocytopenic patients. After 5,000 rads, granulocytes had normal bacterial killing capacity, chemotactic mobility, and normal superoxide production after high-dose stimulation. Nitroblue tetrazolium reduction and ingestion stimulated by complement opsonized oil droplets were not diminished by 5,000- and 10,000-rad irradiation. The functional qualities of cellular blood components other than lymphocytes are not compromised by 5,000 rads. This irradiation dose may be an effective means of controlling incidence of graft-vs-host disease in immunosuppressed patients.

Recent advances in the treatment of patients with thalassemia major have centered around the removal of iron from individuals already overloaded due to repeated transfusions. In this report we present therapeutic maneuvers designed to decrease the rate of iron accumulation. We demonstrate that the persistent maintenance of hematocrits above 35% (“supertransfusion”) is not associated with an increased transfusion requirement because it produces a decrease in whole blood volume (21% +/- 2%). Supertransfusion is also associated with normalization or even prolongation of plasma iron turnover. In addition, we describe a method for obtaining units of blood from normal donors that contain primarily young red cells (“neocytes”). These cells have prolonged in vivo survival as measured by the interval between transfusions (30 +/- 2.5 days to 43 +/- 4.5 days) and 51Cr red cell survival (43.8 days versus 27.8 days). Supertransfusion with neocytes is effective in decreasing the rate of iron accumulation in thalassemia.

Acute reduction in red cell volume (RCV) without significant alterations of blood volume in 22 patients with severe polycythemia secondary to cyanotic congenital heart disease resulted in a decrease in peripheral vascular resistance and an increase in stroke volume, systemic blood flow (SBF), and systemic oxygen transport. These changes are probably related to the decreased blood viscosity and yield shear stress associated with lower red cell concentrations. Hypervolemia in hypoxic polycythemia should be maintained in order to sustain an adequate SBF. In contrast to acute phlebotomy which may be expected to decrease blood oxygen content and SBF, the replacement of whole blood with plasma or 5% albumin is shown to result in an increased systemic blood flow and oxygen delivery.