THE EFFECTS OF TEMPERATURE ON THE FILTRATION OF DILUTED BLOOD THROUGH3 MU-M AND 5 MU-M FILTERS

The effect of temperature on the flow of diluted blood [Hct = 0.21], t hrough 5 mu m Nuclepore filters, is described by the Arrhenius equatio n with an energy of activation of 27.7 kJ/mol, Plasma, diluted with PB S, is almost three times less sensitive to temperature, with an energy of activation of 9.8 kJ/mol, while red cells are of intermediate sens itivity, with an energy of activation of 14.7 kJ/mol, The most sensiti ve elements to changes in temperature are leukocytes, with energies of activation of 31 kJ/mol and 35 kJ/mol for fast-flowing leukocytes (gr anulocytes and lymphocytes) and slow-flowing leukocytes (monocytes) re spectively, Hence, the major determinants of the decline in filterabil ity of blood through micropore filters are the leukocytes, This effect is compounded when blood is kept for 10 minutes or more at 10 degrees C due to activation of granulocytes, which leads to permanent pore bl ocking when the affected blood is filtered at room temperature, The co mbination of increased passage time of leukocytes through peripheral a reas at abnormally low temperatures and subsequent activation might in fluence the flow of blood in non-affected tissues. The effect of tempe rature on the filterability of red blood cells through 3 mu m filters is not described by the Arrhenius equation and the deviations are seen as a gradual change of slope rather than a sharp break between two st raight lines. The data are consistent with a gradual shift in rate lim iting step away from the entry event into pores, which dominates at lo w temperature but becomes progressively less important at elevated tem peratures. The changing parameter is probably the volume of the red ce ll, which is less important when flow is measured through 5 mu m pores .