NITROGEN
FELIX
J.
MATHIEU,
MUSTARD BROWN-PEARCE
M.D.,
PREVIOUS studies in this laboratory have employed nitrogen mustard as an attempt to control growth of Brown-Pearce tumor in the peritoneal cavity of rabbits [l]. One question which arose was whether tumor and tumoritidal drug were suited to one another. In one study on the influence of nitrogen mustard on Brown-Pearce tumor growth, it was shown that nitrogen mustard administered systemically did inhibit growth of tumor in the rabbit eye, but since the animals lost weight the authors agreed that this may be a result of systemic toxicity rather than toxicity to the tumor itself. Since diffusion of materials administered systemically into the anterior chamber of the eye is slow and cannot be expected to be present in any significant concentration, a method was devised which permits the tumor to be in contact with nitrogen mustard prior to transplantation into the anterior chamber of a rabbit’s eye.
METHODS Unselected rabbits four to six weeks of age were used for the eye transplants. BrownFrom the Department of Surgery, Louisiana State University School of Medicine, New Orleans, La. This work was supported in part by U.S. Public Health Service Grant AI-01600 from the National Institute of Allergy and Infectious Diseases, National Institutes of Health. Submitted for publication Apr. 8, 1965.
8
AND
AND
GROWTH TUMOR
ISIDORE
COHN,
OF
JR.,
M.D.
Pearce tumor grown in the anterior chamber of a young rabbit’s eye was used for transplants when the tumor filled the anterior chamber. Mustargen, brand of mechlorethamine hydrochloride, was used as the tumoricidal agent. Series 1 In this series, 12 paired eye transplants were done. Tumor from a single rabbit eye was used so that variations in different eye tumors or difference in susceptibility of the tumor would not be a variable. The tumor was teased and divided into 24 equal parts. Half of these were placed in individual glass tubes containing 1 ml. of sterile normal saline. The other 12 were placed in individual glass tubes containing 0.5 mg. of nitrogen mustard diluted in 1 ml. of sterile normal saline. The tumor was allowed to remain in contact with the solutions in both groups for 30 minutes. At the end of this period the tumor particles were removed from the solutions and packed into individual 1%gauge spinal needles and immediately transferred to the anterior chamber of the rabbit eyes. The rabbits were placed in individual cages and the eyes observed for tumor growth at weekly intervals up to three months. Series 2 After completing the first series the question arose as to whether nitrogen mustard would inhibit the growth of Brown-Pearce
MATHIEU
AND
COHN:
NITROGEN
tumor at concentrations which were less than that used in the first series. Thirteen paired were done. Concentrarabbit experiments tions of nitrogen mustard varying from 0.1 mg. to 1.0 mg. per 1 ml. of saline were placed in contact with the tumor particles for 30 minutes. Saline- and nitrogen-mustard-treated tumor was then transplanted to the anterior chamber of the rabbits’ eyes.
RESULTS In both groups of experiments growth was not observed in the eyes transplanted with tumor pretreated with nitrogen mustard. Doses of nitrogen mustard as low as 0.1 mg. per 1 ml. inhibited tumor growth. In the control groups tumor growth was evident in most cases as early as 7 days with maximal growth occurring between 30 and 50 days. Tumor growth occurred in all but two of the control eyes.
DISCUSSION The anterior chamber of the eye has proven an almost ideal site for observance of growth of tumor transplants. The technique of transfer is simple and a high percentage of takes is obtained. Day by day observance of growth is possible. The tumor antagonist and tumor were brought into contact prior to transplantation
MUSTARD
AND
GROWTH
OF
BROWN-PEARCE
TUMOR
rather than by systemic administration, because substances systemically administered do not readily diffuse into the eye. This technique was considered adequate for the original purpose of this experiment, which was to determine whether nitrogen mustard and Brown-Pearce tumor were suitable tumor and tumor antagonist. Direct toxicity to the rabbit eye by the nitrogen mustard was not observed. There was no inflammation or cloudiness of the eyes so it may be concluded that dosages used were below levels toxic to the eye tissues. CONCLUSIONS A method has been devised to study the effect of nitrogen mustard on growth of Brown-Pearce tumor by bringing the tumor and nitrogen mustard into contact prior to transplantation. Nitrogen mustard has been shown to be effective in inhibiting growth of the BrownPearce tumor; therefore, previous studies utilizing nitrogen mustard in controlling Brown-Pearce tumor in the peritoneal cavity of rabbits must be valid.
REFERENCE 1.
Cohn, I., Jr., Gonzalez, E. A., Jr., Floyd, C. E., Freeman, C. M., and Atik, M. Influence of nitrogen mustard on tumor implantation. J.A.M.A. 185:575, 1963.