Abstract
Cyanate prevents sickling in vitro and apparently prolongs the survival of 51Cr-tagged sickle erythrocytes in vivo. Cautious interpretation is required because the effects of cyanate on 51Cr binding to sickle and fetal hemoglobin-containing red cells are unknown, and comparison of the effect of cyanate on sickle red cell survival to control red cell survival must be performed sequentially. We have studied the survival of sickle reticulocytes utilizing radioactive amino acids that are incorporated into hemoglobin. Two informed adult patients with sickle cell disease were studied. In each study, two 50-ml samples of blood were incubated separately with 14C- and 3H-leucine for 2 hr, after which 50 mM cyanate was added to one aliquot for 1 hr. The cells were then washed and reinfused. Frequent venous samples were obtained, and the specific activities of 14C and 3H in the hemoglobin were followed. The t ½ of the carbamylated cells was tripled, but remained below normal. This method provides a generally useful measurement of the influence of drugs bound to red cells on reticulocyte lifespan. The labels are incorporated into the hemoglobin molecule of the reticulocyte, and simultaneous comparison of the survivals of the same cohort of drug-treated and control cells is achieved.
