Simple and rapid isolation of platelets using Ficoll-Uropoline cushion.

A simplified procedure for separation of human platelets from plasma proteins when a small volume of blood is available has been developed. In this method two centrifugations of platelets layered on Ficoll-Uropoline cushion was applied. In the first step, platelet rich plasma layered over Ficoll-Uropoline solution was centrifuged (700 g, 30 min), bounded platelets recovered with the help of HEPES buffer, and centrifuged again (1000 g, 10 min) on Ficoll-Uropoline cushion. This rapid and simple procedure yielded platelets separated from von Willebrand factor, fibrinogen and albumin, as judged by bioassay and measurement of radiolabeled plasma proteins. The obtained preparation of platelets was stable and the platelet function preserved for 3 h as evidenced by platelet aggregation and fibrinogen binding analysis. The procedure is inexpensive and convenient for small volumes of blood.

Plasma beta-thromboglobulin in acute myocardial infarction with ventricular arrhythmias.

Patients with myocardial infarction, complicated by ventricular arrhythmias (Lown grade greater than or equal to 2), had higher (p less than 0.05) plasma beta-thromboglobulin level than that found in patients with uncomplicated infarction. This indicates higher platelet activation in the former group than in the latter. Such data provide rationale for clinical trial of antiplatelet drugs in cases of myocardial infarction complicated by severe arrhythmias.

Formation of prostacyclin-sensitive platelet aggregates in human whole blood in vitro. Part I. The occurrence of the phenomenon in healthy male volunteers.

When unstirred citrated blood of young males was left to stand at 21 degrees C, the number of free platelets decreased as measured with a whole blood platelet counter. This decrease indicated spontaneous platelet aggregation (SPA) since it was accompanied by the time-dependent increase in platelet micro-aggregates and plasma beta-thromboglobulin while lactate dehydrogenase level did not change significantly. Addition of PGI2 to whole blood increased free platelet count and decreased the number of platelet micro-aggregates. The de-aggregatory effect of PGI2 (measured as a percentage increase in free platelet number) was correlated with the initial amount of platelet micro-aggregates. Blood storage enhanced SPA and de-aggregatory effect of prostacyclin. Immediately after blood collection de-aggregatory effect of prostacyclin was absent. Our results favour an assumption that prostacyclin-sensitive platelet aggregates in blood of young volunteers are formed in vitro rather than in vivo.

Release of prostacyclin (PGI2) by the layers of corpus of rat stomach.

Release of PGI2 by slices of muscularis and mucosa layers of rat corpus stomach was investigated. An anti-aggregatory substance that was released by slices of muscularis was identified as PGI2 in various bioassay systems including anti-serum against PGI2 as well as by stimulation of its generation with AA or PGH2 and by inhibition of this generation with indomethacin or tranylcypromine, respectively. PGI2 was the major PGs released from slices of muscularis. The release of PGI2 from muscularis surpasses a similar release of PGI2 from mucosa by a factor of 10. On the other hand, degradation of exogenous PGI2 was 4 times faster by mucosa than by muscularis slices. Our conclusion is that in the stomach corpus wall of rats, muscularis is the main source of PGI2, which may play a role in regulation of mucosal blood flow.