Experimental studies of factors influencing hepatic metastases. VII. Effect of reticuloendothelial interference.

as being due to a trapping of injected tumor cells as a result of marked swelling of Kupffer cells with sinusoidal occlusion and hepatic parenchymal damage which was observed after the administration of both Thorotrast and India ink. These mechanisms abrogate the necessity of relating such an effect to an inhibitory action of these agents on a specific activity of the reticuloendothelial system associated with tumor resist ance. Established hepatic métastasesof Walker 256 carcinoma fail to influence the phagocytic activity of the reticuloendothelial system as disclosed by a normal blood clearance of carbon particles. Similarly carbon clearance was normal when observed in animals 14 days after tumor cell injection but in whom hepatic métastaseswere not demonstrable