Two previous studies (1, 2) on the angiographic patterns of transplanted and spontaneous malignant tumors in mice have been reported. The first of these dealt with the vascularity of 7 untreated tumors and the second with the vessel response of 5 of these tumors to irradiation. The present communication is concerned with the vascularity of transplanted lymphosarcoma that regressed after administration of systemic nitrogen mustard and compares the effects of irradiation with those of systemic chemotherapy. In all, 387 C3H/Hej mice bearing lymphosarcoma (6C3HED) underwent study: 159 served as controls, 126 were irradiated, and 102 received chemotherapy. method Pieces of tumor measuring approximately 1 mm. were inoculated by trocar into the subcutaneous flank tissue. Angiography was performed on Nembutal-anesthetized mice after the insertion of a polyethylene catheter into the exposed left ventricle, as previously described (1). Thorotrast2 was the contrast material used in all but 18 mice; in this latter group Micropaque3 was employed. Exposures were made on Eastman Kodak Industrial Type M film after the injection of 0.3, 0.5, 1.0, and 1.5 ml. of contrast material. A 0.3 mm. focal spot was used, with a pinhole opening in a lead diaphragm placed just below the tube. Angiograms of the tumor and surrounding tissue were enlarged ten times photographically. The physical factors for the irradiation therapy were: 220 kvp, 1.9 mm. h.v.1. Cu, 15 milliamperes, 450 r per minute at a focal skin distance of 20 cm. through a 0.5 mm. Cu and a 1 mm. Al filter. The mice were anesthetized with intraperitoneal Nembutal and placed in a brass tube which in turn was positioned in a 16 mm. thick lead block. The tumor was irradiated by pulling it out through a slot in the brass tube and anchoring it. The method of microangiography employed was described in a previous publication (3). Mechlorethamine hydrochloride4 was given in 0.9 per cent NaCl diluent intra-peritoneally in a dose of 0.1 mg./kg. After several dosage schedules, we found that this amount of drug produced the desired regression. Angiography was performed on the second through the seventh days. results Of the 387 mice with lymphosarcoma, 159 were untreated. The tumors were poorly demarcated from the surrounding normal tissue and spread along the surface of the body (Fig. 1). The larger tumor vessels tended to parallel the main body axis although they were often tortuous. Larger collections of contrast medium (“lakes”) as seen in some other types of malignant tumors in mice were uncommon. Fine vessels often joined the larger vessels at right angles. In 126 mice the tumors were studied after irradiation, which ranged between 400 and 3,200 r. The higher doses were fractionated, usually in three equal parts, over a ten- to twelve-day period. Even the smaller radiation doses resulted in stabilization. The vascularity increased as the tumors started to recur.
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Mar 1, 1992
Robert Wilson + 1
Open Access