The tumor-cell-releasing machine.

We describe the construction of a machine for the injection of 10- to 100-microliter volumes of viable cells in suspension. The cells are maintained in a tissue culture environment and can be injected according to a preprogrammed schedule. Preliminary results show that the tumor incidence and metastasis pattern of TA3Ha cells injected intravenously into mice are the same if the cells are injected in a single dose, or administered in 20 fractions during 3 h.