6-ketoprostaglandin-f1-alpha and Purpura--Thrombotic-Thrombocytopenic

The stability of prostacyclin (PGI2) in whole blood and plasma was studied in vitro by measuring the disappearance rate of labeled prostacyclin during a 37 degrees C incubation. Prostacyclin was assayed using a quantitative chromatographic method. The half-life of PGI2 was 6.3 +/- 0.8 minutes (mean +/- s.d., n = 6) in citrated human whole blood, significantly shorter (p less than 0.001) than the 10.7 +/- 2.3 minute half-life in citrated human plasma (n = 7). Prior freezing and thawing of plasma did not affect the rate of PGI2 hydrolysis. These values, including the prolonged half-life in plasma, were similar in the blood (5.4 +/- 1.8 min, n = 7) and plasma (9.0 +/- 1.9 min, n = 14) of diabetic patients. In plasma samples from patients with thrombotic thrombocytopenic purpura, the half-life of prostacyclin (4.9 +/- 1.0 min, n = 4) was significantly shortened (p less than 0.001) compared to that in plasma from normal volunteers. The stability of prostacyclin in rabbit blood and plasma was also quantified. The PGI2 half-life in citrated rabbit plasma (10.8 +/- 1.1 min, n = 3) was similar to that in citrated human plasma from control subjects. In contrast to the findings in human blood, the half-life of PGI2 in citrated rabbit whole blood (11.7 +/- 3.3 min, n = 4) was not different from the rabbit plasma value. Substitution of EDTA for citrate did not affect the half-life in rabbit blood or plasma.

Topics: 6-Ketoprostaglandin F1 alpha; Anemia, Hemolytic; Animals; Autoimmune Diseases; Brain; Chromatography, High Pressure Liquid; Diabetes Mellitus; Epoprostenol; Half-Life; Humans; Hydrogen-Ion Concentration; Kinetics; Purpura, Thrombotic Thrombocytopenic; Rabbits; Reference Values; Species Specificity; Tritium

Topics: 6-Ketoprostaglandin F1 alpha; Adolescent; Epoprostenol; Female; Humans; Purpura, Thrombotic Thrombocytopenic; Pyrazoles; Pyrazolones

Topics: 6-Ketoprostaglandin F1 alpha; Aorta; Female; Hemolytic-Uremic Syndrome; Humans; Male; Prostaglandins F; Purpura, Thrombotic Thrombocytopenic

A study was conducted to find whether a deficiency in prostacyclin (prostaglandin I2; PGI2) is implicated in the pathogenesis of thrombotic thrombocytopenic purpura. Plasma samples from two patients with the disease before treatment and from 22 healthy controls were therefore assayed for concentrations of 6-oxo-PGF1 alpha and thromboxane B2, the stable metabolites of PGI2 and thromboxane A2, respectively. Neither of the patients responded to treatment, which in one case included an infusion of PGI2. Both patients had normal concentrations of 6-oxo-PGF1 alpha and thromboxane B2, thus implying that circulating amounts of PGI2 and thromboxane A2 were also normal. These findings suggest that 6-oxo-PGF1 alpha may be detectable in normal amounts in thrombotic thrombocytopenic purpura and that the condition need not be associated with a high concentration of thromboxane A2.

Topics: 6-Ketoprostaglandin F1 alpha; Adult; Epoprostenol; Female; Humans; Male; Middle Aged; Prostaglandins; Purpura, Thrombotic Thrombocytopenic; Thromboxane A2; Thromboxane B2; Thromboxanes