Ruth M. Merwin

Induction of Plasma-Cell Neoplasms and Fibrosarcomas in BALB/c Mice Carrying Diffusion Chambers.

Summary Seven plasma-cell neoplasms and 6 fibrosarcomas developed in strain BALB/c mice that carried diffusion chambers in the peritoneal cavity. The diffusion chambers contained mammary tumor tissue obtained from strain C3H mice with the milk agent. Five plasma-cell tumors and all sarcomas were successfully transplanted to strain BALB/c mice. The 2 plasma-cell tumors and the 2 sarcomas transplanted to C3H mice failed to grow.

vascular patterns in tissues and grafts within transparent chambers in mice.

The method used in the studies described here had its origin in the pioneer work of Professor Eliot Clark and his students. They developed a method for introducing transparent chambers into the ears of rabbits (1, 2). We have modified these procedures for use in various problems of cancer research in which the mouse has been the experimental animal (3-5). It was found possible to alter the skin-flap method of Williams (6), and thus to introduce a chamber into a dorsal fold of skin pulled away from the body of the mouse (fig. 1). The operation is carried out under Nembutal anesthesia in approximately one hour. Observations in the non-anesthetized animal (fig. 2) may be made immediately thereafter and daily for periods varying from 30 to 60 days. An area of skin 14 mm in diameter is visible through the cover slip. The skin is approximately one-half millimeter thick. The peripheral nerves embedded in a layer of avascular connective tissue lie directly beneath the cover slip. Beneath this layer is a thin sheet of striated muscle (panniculus carnosus). As one focuses down through the muscle layer, one sees in turn a layer of connective tissue, dermis, and epidermis. Three designs of chamber are illustrated (fig. 3), but we are primarily concerned, for purposes of this discussion, with the preformed tissue type. The round table design is also useful in circulatory studies because it permits increased resolution of fine structural details of blood vessels (fig. 3). A number of observations on tissues and grafts within the chamber may be of interest in considering vascular patterns as related to function.