| Popis: |
Platelet activation occurs in a variety of thrombotic disease states and may be monitored via measurement of Platelet Factor 4 (PF4) levels in plasma. In order for PF4 levels to reflect in vivo activation, care must be taken to eliminate in vitro α -granule release during the collection and preparation of blood specimens. Thrombotect is an evacuated blood collection tube containing an anticoagulant (EDTA) and two platelet inhibitors (2-chloroadenosine and procaine-HCl). This system is effective in preventing in vitro release under a variety of centrifugation conditions. Subsequent to a 30 minute icing step, whole blood samples may be centrifuged at room temperature and one of three centrifugation speeds - 2500 × g for 20 minutes,1500 × g for 30 minutes, and 1000 × g for 40 minutes. Plasma specimens from normal individuals were assayed after being prepared under the above conditions. PF4 levels were as follows: 2500 × g, *2.79 ± 1.00 (73); 1500 × g, 3.84 ±1.78 (20); 1000 × g, 3.35 ± 1.65 (20). Variations in the temperature of centrifugation had little effect on the ability of Thrombotect to inhibit PF4 release, whereas other commonly used blood collection cocktails became progressively less effective with increasing temperature.*(Mean PF4 in ng/ml ± 1 S.D., “n” values in parenthesis). Results similar to those obtained for EDTA/Theophylline were obtained when EDTA was used in conjunction with adenosine and/or aspirin. The Thrombotect system has been employed in an examination of PF4 levels in a variety of thrombotic disease states. It also provides an excellent collection system for use with other “platelet-release” assays. |
