Influence of blood corpuscles on the ultrafiltration of various proteins

The ultrafiltration characteristics of a commercial dialyzer were examined by measuring the sieving coefficient (s.c.) for three proteins, i.e., cytochrome c, chymotrypsinogen, and albumin, in a bovine blood system. Test blood was passed through a filter at a blood flow rate of 200 ml/min and filtrate was collected at an ultrafiltration flow rate of 10 ml/min from a port located near the blood inlet. The s.c. for cytochrome c and chymotrypsinogen in bovine blood sharply increased at the beginning of the experiment and reached a steady value that was about 60% of that obtained in an aqueous solution system. This may have been caused by the masking effect of the erythrocytes. The s.c. for albumin at steady state in bovine blood that contained added albumin only was almost the same as that obtained in the aqueous solution system. When all three proteins were added to bovine blood, however, the s.c. for albumin showed a steady value (after a slight decrease at the beginning of the experiment) the absolute value of which was higher than that found in the aqueous solution system. This phenomenon may have been caused by the stirring effect of erythrocytes that would disturb the concentration polarization of albumin formed near the membrane.