| 摘要 |
A whole blood aggregometer of red blood cells (RBC) consists of a transparent tube containing freshly drawn heparinized blood, and a densitometer head which is attached to the tube. The densitometer head consists of a light source and a light detector to monitor changes in optical density of the blood in the tube. The blood in the tube is first subjected to rapid flow with a solenoid, so that the wall shear rate of the blood approximates to 500 s-1. The shear gives rise to a rapid increase in optical density of the blood due to dispersion of the blood corpuscles. The blood is then brought abruptly to a full stop. After the flow has stopped, the densitometer head reveals a gradual decrease in optical density in association with RBC aggregate formation. The resultant pattern is termed as an "RBC aggregogram". The RBC aggregogram exhibits a quasi-exponential decay in its initial part, which is followed by an asymptotical decrease. A mathematical procedure is employed to calculate the rate constant of the initial decrease from the two values on the RBC aggregogram at 10 s and 20 s. The rate constant k10 is 0.192+0.028 for feline blood, and 0.129+0.012 for human blood. The RBC aggregation rate varies linearly with the hematocrit below 40%.
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