Richard A. Malmgren

Reduced antibody titers in mice treated with carcinogenic and cancer chemotherapeutic agents.

Summary A number of cancer chemo-therapeutic agents, carcinogens and their non-carcinogenic analogues were tested for their effect on sheep cell hemolysin production in mice. All of the chemotherapeutic agents, with the exception of furacin, depressed the antibody titers. All of the carcinogens also produced a marked depression of the antibody levels but their non-carcinogenic analogues were without effect. None of the substances tested inhibited preformed antibodies in vivo or in vitro.

Malignant lymphomas and plasmacytosis in mice under prolonged immunosuppression and persistent antigenic stimulation.

SUMMARY BALB/c and C57BL mice were kept for prolonged periods on immunosuppressive treatment combined with persistent antigenic stimulation. Azathioprine (Imuran; Burroughs Wellcome) or antilymphocyte serum was used as an immunosuppressant, and lactic dehydrogenase elevating virus (LDV), vaccinia virus (VAC), complete Freunds adjuvant (TB; Difco), or HeLa cells were used as antigens. Control mice were untreated or were kept on immunosuppression or antigenic stimulation alone. Malignant lymphoblastic lymphomas developed in 20% of BALB/c mice treated with azathioprine and antigens. No lymphomas were observed in control mice. Immature plasmacytoses developed in 40% of BALB/c and in 27% of C57BL mice when they were treated with antilymphocyte serum (ALS), with or without antigenic stimulation. In addition, chronic ALS administration led to membranous glomerulitis and glomerulonephrosis in 8% of all treated mice, the changes being most severe in antigenically challenged animals. Lymphoma development is interpreted as a direct result of persistent antigenic stimulation in immunosuppressed mice, and a possible pathogenic mechanism is discussed. The renal lesions are thought to be caused by circulating antigen-antibody complexes.

In vitro neoplastic transformation of newborn hamster salivary-gland tissue by oncogenic DNA viruses

Explant cultures of newborn hamster salivary‐glands were infected with 4 oncogenic DNA viruses: polyoma virus, human adenovirus 12, simian virus 40 (SV40) and the LLE46 strain of adenovirus 7 (the adenovirus 7‐SV40 “hybrid”). Only SV40 and LLE46 infected tissues underwent “transformation.” Subcutaneous injection of SV40 transformed cells into irradiated adult hamsters produced fibrosarcomas. Subcutaneous injection of LLE46 transformed cells, however, produced tumors which were bimorphic with 2 distinct histological elements, one composed of small hyperchromatic undifferentiated cells resembling an adenovirus type tumor and the other resembling an SV40‐induced sarcoma. No evidence of salivary‐gland function as indicated by amylase production could be demonstrated in the transformed cultures or in the tumors which they produced.

Significance of cancer cells in operative wounds

Abstract A comprehensive evaluation of 184 surgical patients who had cytologic examination of both wound washings and drainages revealed that seventeen patients (9 per cent) had tumor cells identified in the drainage fluid and twenty-four (13 per cent) in the washings from their wound, collected immediately after en bloc tumor resection. Only four patients had both positive wound washings and wound drainages. In those patients followed up for more than one year, an apparent trend toward an increased tumor recurrence rate associated with positive washing and drainages was not found to be statistically significant. The results of this study suggest that the identification of tumor cells in either the wound washings or wound drainages appears to be of little prognostic importance with regard to the development of local wound recurrence in patients who had what was determined to be complete tumor resection. The relative insensitivity of available methods for detecting malignant contamination of a surgical wound is evidenced by the fact that only a small number of patients with incompletely removed malignant lesions showed cytologic evidence of cancer cell wound seeding. The present inability to attach clear prognostic significance to wound seeding as well as the demonstration of circulating tumor cells may call for a revised concept of malignant disease that stresses the importance of immunologic relationships between tumor and host.

Comparison of techniques for obtaining single cell suspensions from tumors.

To evaluate the most efficient method for preparation of single cell suspensions from viable tumor tissue for use in in vivo experiments, a mouse methylcholanthrene-induced sarcoma and a polyoma virus-induced sarcoma were used. The tumor cells were disassociated by four different methods and the state of viability, yield of single cells per 0.1 gram of tumor, and the quantity of cell debris were determined. The effect on transplantability of each of the methods was assessed by injection s.c. of a constant number of viable cells. Of the four methods tested, the cell preparation resulting from treatment of the tumor with the proteolytic enzyme “Pronase” yielded the highest number of viable cells and the smallest quantity of cell debris. Transplantability of the tumor cell suspension prepared by each of the methods was similar when a constant number of viable cells was injected.

Induction of Neoplasia in vitro in Hamster Kidney Tissue by Adenovirus 7-SV40 “Hybrid” Strain (LLE46)

Summary Newborn hamster kidney cell cultures were transformed in vitro by LLE46 virus, an adenovirus 7-SV40 hybrid, and by SV40. The cultures transformed by both viruses consisted of rapidly growing cuboidal and polygonal cells, although those in the LLE46 cultures were smaller and had less tendency to grow in clumps. Neither infectious adenovirus 7 nor SV40 could be recovered from the transformed cells. More than 90% of the cells in both the LLE46 and the SV40 cultures contained persistent intranuclear SV40 T antigen while no adenovirus 12 or 7 T antigens were demonstrable. Tumors were rapidly produced when both types of transformed cells were injected into newborn hamsters, and into irradiated young adult hamsters. As previously described, the tumors produced by the SV40 transformed cells were predominantly carcinomas with areas of tubular differentiation. Those produced by the LLE46 transformed cells, however, were predominantly undifferentiated and histologically similar to adenovirus 12 tumors. Although they did contain a few small foci resembling SV40 sarcomas, no tubular epithelial structures were seen.