Abstract: | Microcalorimetric measurements have been made of the heat production in whole blood and its major cell fractions. All measurements were made with samples from normal subjects. The average heat effect value found (plus or minus S.D.) for whole blood was 62 plus or minus 7 mW/l. The value obtained for erythrocytes was 82 plus or minus 6 mW per liter of packed cells suspended in phosphate buffer at pH 7.4. For lymphocytes and for polymorphonuclear leukocytes heat effect values were 4.6 plus or minus 1.8 and 1.2 plus or minus 0.4 pW/cell, respectively, for cells suspended in buffer. For plasma suspensions corresponding values were 2.2 plus or minus 1.4 and 3.5 plus or minus 1.0 pW/cell, respectively. For thrombocytes suspended in plasma the heat effect value was 59 plus or minus 8 fW/cell. Heat production in cell-free plasma was close to zero. Using heat effect values determined for the different cell fractions, values could be calculated for whole blood samples which were in full agreement with the values obtained by direct measurements of whole blood. |