van Oost B A, Timmermans A P, Sixma J J
Blood. 1984 Feb;63(2):482-5.
The relation between platelet buoyant density and beta-thromboglobulin (beta-TG), a marker for platelet alpha-granule content, was assessed by three independent approaches. (1) Platelets were separated on iso-osmolar discontinuous Stractan density gradients into five fractions, ranging in density from 1.061 g/ml to 1.091 g/ml (20 degrees C). The beta-TG content (mean +/- SD, n = 17) increased with the platelet density from 27.8 +/- 8.6 micrograms beta-TG/10(9) cells (20% less-dense platelets) up to 65.6 +/- 15.5 micrograms beta-TG/10(9) cells (15% most-dense platelets). (2) Activation of platelets in platelet-rich plasma with thrombin, adenosine diphosphate, collagen, or epinephrine resulted in a decreased density of the platelets. This was only seen when there was simultaneous secretion of beta-TG. (3) The less-dense and the more-dense platelet fractions, after isolation by density gradient centrifugation, were separately treated with thrombin. After complete degranulation, the density distribution of the originally less-dense and more-dense platelets were identical and were much narrower than the density distribution of resting platelets.
通过三种独立的方法评估了血小板浮力密度与β-血小板球蛋白（β-TG，一种血小板α-颗粒含量的标志物）之间的关系。（1）将血小板在等渗不连续的Stractan密度梯度上分离成五个组分，密度范围为1.061 g/ml至1.091 g/ml（20℃）。β-TG含量（平均值±标准差，n = 17）随着血小板密度的增加而增加，从27.8±8.6微克β-TG/10⁹个细胞（密度较低的血小板20%）增至65.6±15.5微克β-TG/10⁹个细胞（密度最高的血小板15%）。（2）用凝血酶、二磷酸腺苷、胶原或肾上腺素激活富含血小板血浆中的血小板会导致血小板密度降低。只有在同时分泌β-TG时才会出现这种情况。（3）通过密度梯度离心分离后，密度较低和较高的血小板组分分别用凝血酶处理。完全脱颗粒后，原来密度较低和较高的血小板的密度分布相同，且比静息血小板的密度分布窄得多。
