thiopental and Fibrosarcoma

Three cloned populations of tumor cells obtained from a murine fibrosarcoma were able to remain viable for a long period of time in syngeneic mice which failed to exhibit clinically evident tumors following tumor cell inoculation. Viable tumor cells under such conditions can be considered to be in a dormant state. On the basis of past studies, two of the lines were shown to have low malignant potential, while the third line was shown to have a higher degree of malignant potential. The rates of spontaneous reactivation of tumor growth in animals carrying the low malignant cells were 3 and 4%, while a rate of 30% was observed in animals with the more malignant cells. Treatment of animals carrying the low malignant cells in a dormant state with anesthesia alone, (thiopental) or with anethesia and surgery, increased the rate of reactivation to 20-22%.

Topics: Anesthesia; Animals; Female; Fibrosarcoma; Halothane; Mice; Mice, Inbred C57BL; Models, Biological; Sarcoma, Experimental; Surgical Procedures, Operative; Thiopental

The effect of thiopental, halothane and surgery on specific arms of the immune response of normal mice was studied. These experiments represent the first step in localizing a potentially correctable anesthesia/surgery-induced defect in immune reactivity which may be involved with postoperative increases in tumor growth. The delayed-type hypersensitivity (DTH) response of mice to 2,4-dinitrochlorobenzene (DNCB) was studied. Combinations of induction and inhalation anesthesia and surgery were administered at various phases of the immune response to DNCB. Thiopental impaired the afferent response while halothane impaired the efferent response. When the agents were combined, both arms of the immune response were suppressed. A surgical procedure, in most experiments, did not produce a greater immunosuppression than thiopental and halothane. The administration of an immunorestorative agent, thiabendazole, returned reactivity to normal levels. Thiopental and halothane either affect different immune cell populations or they affect different functions of a cell population active in both arms of the DTH response. In relation to tumor growth, the degree of suppression may not be as significant as the cell population impaired.

Topics: Anesthesia; Animals; Dinitrochlorobenzene; Drug Synergism; Female; Fibrosarcoma; Halothane; Hypersensitivity, Delayed; Immunity, Cellular; Mice; Mice, Inbred C57BL; Neoplasms, Experimental; Surgical Procedures, Operative; Thiopental

This set of experiments was devised to determine the effects of the commonly employed anesthetic induction agent, thiopental, on the incidence of pulmonary metastases in a murine fibrosarcoma system. A correlation was made with cell-mediated immune responses in vivo and in vitro. In two separate experiments, thiopental-treated mice had a significantly increased incidence of pulmonary metastases. This was correlated with an impaired delayed hypersensitivity reaction to the de novo antigen. 2,4-dinitrochlorobenzene (DNCB) and a suppressed mixed leukocyte culture (MLC) reaction. However, if animals were sensitized with DNCB 5 days prior to receiving pentothal, no impairment of DNCB reactivity was noted. This suggests strongly that the observed defect is in the afferent arm of the immune response. Thiopental suppresses cell-mediated immune responses in this system, and the observed biologic consequence is an increase in pulmonary metastases.

Topics: Anesthetics; Animals; Dinitrochlorobenzene; Fibrosarcoma; Hypersensitivity, Delayed; Immunosuppression Therapy; Lung Neoplasms; Lymphocyte Culture Test, Mixed; Mice; Mice, Inbred C57BL; Neoplasm Metastasis; Neoplasms, Experimental; Thiopental