Thymus and Node Labelling by Intramediastinal Injection of Tritiated Tracers and Its Bearing on Present Concepts of Lymphocyte Cytokinetics

Abstract

Since current intravenous or subcutaneous injection of 3H‐thymidine produces a relatively weak labelling of the thymus, an attempt was made to improve this labelling. The newly devised procedure, which consists in injecting the marker intramediastinally, labels the thymus much more heavily than the aforementioned techniques. The observations revealed that the inadequate labelling resulting from intravenous or subcutaneous injections is due to the non‐uniform availability of 3H‐thymidine and that this shortcoming can be rectified by using the intramediastinal route.