Liquid scintillation counting for measurement of tritiated uptake in lymphocyte transformation in vitro: a new direct-suspension procedure.

Liquid scintillation counting of trichloracetic acid extracts of [3H] TdR-labelled lymphocytes has been studied by a direct suspension method without previous solubilization. In this new method, mixing of the labelled powder in water suspension with Scintillator Emulsifying Mixture (SEM) results in a firm gel whose mechanical properties provide an heterogeneous sample ready for counting. Counting efficiency and stability of such samples are related to the amount of labelled cells. Comparative studies with standard hyamine procedure have shown that this simple and rapid method gives reliable results.