Hemodynamic and plasma catecholamine responses to hyperthermic cancer therapy in humans.

Cancer patients, treated with hyperthermia (to 41.5 degrees C) under thiopental and fentanyl anesthesia, had smaller increases in heart rate and cardiac index and lesser decreases in mean arterial pressure than those reported in normal volunteers. At basal body temperature anesthesia did not alter catecholamine levels. Increasing body temperature to 39.5 degrees C and 41.5 degrees C resulted in parallel increases in heart rate and cardiac index that were directly related to the increases in plasma norepinephrine levels. At basal temperature cutaneous venous plasma norepinephrine levels exceeded those of arterial; mixed-venous plasma levels were intermediate. At 39.5 degrees C and 41.5 degrees C there were sequential increases in plasma norepinephrine. The increases in mixed-venous and arterial norepinephrine were significantly greater than in cutaneous venous blood. The differential increases in norepinephrine levels in cutaneous venous, mixed-venous, and arterial blood indicate that during hyperthermia sympathetic nerve activity in skin is decreased while that in other areas is increased, suggesting that alterations in sympathetic activity modulate the hemodynamic changes that attend hyperthermia in man.

Potassium clearance and reactive gliosis in the alumina gel lesion.

Potassium accumulation or impaired potassium clearance has been hypothesized to contribute to epileptogenesis in gliotic epileptogenic foci. To test this hypothesis, potassium clearance rates following direct cortical stimulation were measured in the cortex of monkeys rendered epileptic by the injection of alumina gel into the motor area. Reactive gliosis at the sites in which potassium clearance was measured was then quantitated histologically and compared with potassium clearance rates. Dense gliosis was associated with slowed potassium clearance, although the base-line potassium level appeared no different in actively epileptogenic areas or gliotic areas compared with normal areas. Possible mechanisms and significance of slowed potassium clearance in the alumina focus are discussed.