The invention tissue injection catheters are designed to facilitate injection of a therapeutic or diagnostic agent to an interior body cavity, especially the myocardium or epicardium of the heart with precisely controlled depth penetration. The invention injection catheters, which include mechanisms for precisely controlling the length of needle tip exposed for tissue penetration, are designed to be used in an assemblage with a sterile container and delivery actuator for reinjection of autologous cell-containing fluids, such as autologous bone marrow aspirate. In preferred embodiments, the assemblage is designed to be hand-held. When used in such an assemblage, the invention catheters are particularly useful as a gene delivery device to effect angiogenesis of ischemic areas of the heart.