Whole body counting in erythrocyte survival studies.

In Cancer Research, 26: 198-201, Feb. 1966, Brodsky et at. describe a method for determining the red cell survival in mice, based on whole-body counting after injection of 51Cr-labeled red cells. Inspired by this article, we decided to use the method which seemed to have some obvious advantages over the sampling method. Three hundred /L1. of red cells, labeled with 1 uc. 51Cr ( specific activity 72.8 mC./ mg. were given to each mouse ( female Swiss Webster, 25 Cm. ). The T0 plus 24 hr. whole-body count was used as the 100 per cent value for the calculation of T/2. In our normal mice ( 25 ) we found a T/2 of 18-20 days, which is the same as the value given by Brodsky. However, to check the method for its ability to detect hemolysis, we induced severe hemolytic anemia in groups of mice by s.c. injection of a 0.2 per cent phenylhydrazine solution in saline. Doses of 0.5, 1.0 and 2.0 mg. were given on three consecutive days. The injection of phenylhydrazine was started on the day after injection of the labeled cells. The hematocnt values dropped to 25-30 per cent and the reticulocyte count increased to almost 100 per cent in the following days. As can be seen from Figure 1, there was no accelerated decline in the radioactivity in the phenylhydrazine-treated animals. Two separate series were run with an equal