[Enhancement of antitumor effect of MMC on Walker 256 by intra-arterial administration of noradrenaline in hyperthermia].

We performed a study of hyperthermia while injecting 0.05% of Noradrenaline following MMC for 10 minutes into the feeding artery of Walker-256 carcinosarcomas implanted 6 days earlier into the s.c. dorsum side of hindpaw of Wistar rats. The tumor growth rates on the 6th day after treatment by warning tumor in hot water (40 degrees C, 44 degrees C) for 10 minutes with or without Noradrenaline, were 0.7 +/- 0.6, 2.1 +/- 0.9 (40 degrees C) and 0.2 +/- 0.3, 0.0 +/- 0.0 (44 degrees C), respectively. The data suggested that tumor ischemia induced by a vasoconstrictive drug may enhance the antitumor effect in low grade warning therapy (40 degrees C). An injection of warmed physiological saline (50 degrees C) may heat the tumor vessels on the tumor surface and showed enhanced antitumor effects as a from of hyperthermia. The target area of the tumor for hyperthermia can be considered to be the tumor vessels on the tumor surface.