The Effect of Platelet Number and Haematocrit on Whole Blood Thromboxane Synthesis

Summary

Whole blood, allowed to clot at 37° C in glass tubes, synthesized thromboxane A₂ (TxA₂) as determined by radioimmunoassay for thromboxane B₂ (TxB₂). The time course for TxB₂ synthesis showed no further increase after 60 min and the concentration of TxB₂ in serum obtained from 60 normal subjects positively correlated with the whole blood platelet count in EDTA anticoagulated blood from the same donor.

Patients with chronic renal failure produced less serum TxB₂ than age- and sex-matched controls; they also had lower haematocrits. After re-calculating TxB₂ production as a function of platelet count and haematocrit all but one of the patients fell in the range of values obtained for controls. These results suggest that chronic renal failure may not be associated with a cyclooxygenase defect and that clotted whole blood TxB₂ production should be expressed as a function of platelet count and haematocrit.

Keywords

Thromboxane - Platelets - Haematocrit - Chronic renal failure

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