A technique of creating localized heating by implanting metallic materials in the brain and inserting the head into a radiofrequency electromagnetic field is described. The heating properties of various materials for implantation were studied, and the two best materials were carbon steel rods and Hysterloy (1000 and 655 cal/g-min, respectively). Heating of these materials was done primarily by eddy current since their heating rates were significantly affected by their shapes and orientation in the field, rods oriented parallel to the field producing the most heat. There is evidence that warmer cells have a greater uptake of chemotherapeutic agents. This suggests a combined therapeutic approach employing localized brain heating in conjunction with systemic or intrathecal chemotherapy. In this way, large doses of chemotherapeutic drugs might be concentrated in a warmed brain tumor while toxicity is prevented by keeping the rest of the brain and body hypothermic.

Alloys↗

PubMedDate not supplied

Regulation of concanavalin A-activated suppressor cell activity by interferon.

In addition to its antiviral activity, interferon (IF) has been shown to have a wide range of immunoregulatory effects in vivo and in vitro. IF has been observed to be produced by concanavalin A (Con A)-activated suppressor cells and has also been postulated to be of importance in modulating their suppressor activity. To explore this possibility further, we examined the capacity of interferon-treated Con A-activated suppressor cells to alter the normal mitogenic response to Con A. Con A-activated suppressor cells were resistant to treatment with IF and no effect of either lymphoblastoid or leukocyte IF, when utilized in concentrations ranging from 1-1000 U/ml, could be shown on the suppressor activity of Con A-activated cells.

Cells, Cultured↗