Microcalorimetric studies of human platelet metabolism at rest. Influence of pH, temperature, cell concentration, preparation methods and storage.

Heat production in human platelets has been measured under different conditions of pH, temp., cell concentration, preparation and storage time. The heat effect was found to increase linearly in the pH range 7.00-7.95, by 20% per pH unit. The temp. coefficient for the heat effect was determined to be Q10 = 2.0 for the temp. interval 32-42 degrees C. Heat production per cell was not significantly affected by variations in cell concentration, or by storage for several hours at room temp. When citrate replaced heparin as anticoagulant significantly higher heat effect values were found.