Oncolysis by Clostridia. v. Transplanted Tumors of the Hamster.

MATERIALS AND METHODS Tumors.—The tumor material used was derived from the hamster tumors which have been described by Fortner et dl. (l, 2) and had been carried for about a year in this laboratory. The following lines were used: amelanotic melanoma #3 (A. Mel. #3), amelanotic melanoma #4 (A. Mel. #4), renal adenocarcinoma #1 (R. Ca. #1). adrenal cortical carcinoma #4 (Ad. Ca. #4), cystadenocarcinoma of the liver #1 (Hep. #1). A suspension of tumor in physiological saline (Hanks BSS) was prepared (1:2 or 1:5), and 0.5 ml. of the suspen sion was transplanted subcutaneously into the left flank of the animals. The period for the development of nodules of optimal size varied from 8 to 14 days, depending on the type of tumor. The A. Mel. # 3 grew slowly, but the A. Mel. #4 showed pronounced formation of métastases even while the primary tumor was still small, and the animals died within 8 days (for further details see Fortner et al. [l, 2]). Therapy.—Animals with tumors which were growing well received single intravenous injections of 100-200 million spores of Cl. butyricum (M-55). The time of injection was chosen in such a manner that optimal oncolysis could be expected to occur within the normal survival time of the tumor-bearing animals. The optimal times of treat ment after transplantation were on the following days: For the A. Mel. #3, on days 10-11; for the A. Mel. #4, on day 3; for the R. Ca. # 1 and the Ad. Ca. #4, on days 4-7; and for Hep. # 1 on about day 7. In survival time experiments the experimental results were evaluated by recording the average survival time, the number of tumors lysed, and the percentage of oncolysis occurring in the primary tumor. Smears of the lysed