Effect of incubation time on adenoviral mediated intra-arterial tumor transfection. Cremaster tumor bearing animals were infused with 1 × 1010 Ad-CMV-Luc using the surgical approach described in materials and methods. After intra-arterial adenoviral infusion was completed, the cremasters bearing tumors were left to incubate for either 5 minutes (n = 8), 30 minutes (n = 8) or 60 minutes (n = 8). After the times had elapsed, clamps were released and rats were left to live for 72 hrs. The rats were then sacrificed and the samples were processed as described in materials and methods. The data presented suggest that intra-arterial adenoviral mediated tumor transfection could be achieved optimally with a dwelling time of 30 minutes.