A Microcalorimetric Study of Resting and Activated Cellular Systems

Sammanfattning: Several cell types and nerve tissue have been studied using a combination of microcalorimetry and other methods. The heat production rate and its pH dependence of normal and transformed 3T3 cells were studied. The transformed cells manifested a higher heat production rate and a larger anaerobic contribution to the total catabolism than did the non-transformed cells. Moreover, the transformed cell line was characterized by a more pH-dependent metabolism than was the normal parental cell line. Human lymphocytes were characterized thermochemically. A heat production rate of 1 pW per cell was observed. This calorimetric value was in agreement with the value calculated from analytical data. Lymphocytes stimulated with phytohaemagglutinin showed an immediate increase in thermal power, a two-fold increase in lactate production and a decrease in oxygen consumption. The behaviour of rat peritoneal macrophages under normal conditions, experimental acute liver injury (ALI) and acute renal failure (RF) were studied by use of microcalorimetry and luminometry. The two techniques gave different results for the ALI and RF groups, indicating differences in the mechanisms by which these two conditions affect the macrophage system. The effects of endotoxin and Lactobacillus pretreatments in acute liver injury induced by D-galactosamine were studied. The results may explain why pretreatment with endotoxin is beneficial in acute liver injury induced by D-galactosamine, but not with Gram positive bacteria including Lactobacillus. Microcalorimetry was used to study the thermal power from the regenerating rat vagus nerve continuously for several days. The truncated insulin-like growth factor (IGF-1) increased the thermal power whereas it was decreased by vinblastine. The results suggest the fraction of the thermal power related to axonal transport or to proliferation of Schwann cells.