Wadenvik H, Kutti J
Department of Medicine, Ostra Hospital, Gothenburg University, Sweden.
Br J Haematol. 1991 Aug;78(4):523-8. doi: 10.1111/j.1365-2141.1991.tb04482.x.
The in vivo kinetics of simultaneously injected 51Cr- and 111In-labelled platelets was investigated in 20 healthy male volunteers. The studies were carried out using both fresh platelets and platelets stored for 5 d at 22 degrees C; the disappearance of platelet-bound radioactivity was measured on whole blood samples as well as platelet pellets. Compared to 111In, the labelling efficiency was notably lower for 51Cr, and a higher amount of 51Cr was bound to contaminating red cells. As regards the fresh platelets, only small dissimilarities were observed in the in vivo kinetics obtained with the two labels. 51Cr yielded a slightly higher platelet recovery and longer T1/2 than 111In, when whole blood samples were used for calculations; no differences were seen when using platelet pellets. When stored platelets were studied, 51Cr gave significantly longer T1/2 and mean life-span (MLS) than did 111In. This difference was present for all mathematical models used for the calculation of MLS, and when whole blood samples as well as platelet pellets were employed. It was demonstrated that the estimation of MLS was also highly dependent upon techniques of blood sampling and curve fitting. Calculation, in which the initial data points were excluded, gave consistently longer MLS (P less than 0.0001), as compared to when all data points were included. Furthermore, when all survival studies were grouped together, calculations using platelet pellets gave a significantly (P less than 0.001) shorter platelet MLS than calculations using whole blood samples. It is concluded that both 51Cr and 111In are acceptable as radiolabels for both fresh and stored platelets. However, it appears that the viability of stored platelets may be influenced by the choice of label, and caution must be taken when these isotopes are used together in dual tracer experiments. Also, our results show that a meticulously standardized processing of blood samples and experimental data is required to enable interlaboratory comparisons of the results.
在20名健康男性志愿者中研究了同时注射的51Cr和111In标记血小板的体内动力学。研究使用新鲜血小板以及在22℃下储存5天的血小板进行；在全血样本以及血小板沉淀上测量血小板结合放射性的消失情况。与111In相比，51Cr的标记效率显著更低，并且有更多的51Cr与污染的红细胞结合。对于新鲜血小板，用两种标记获得的体内动力学仅观察到微小差异。当使用全血样本进行计算时，51Cr产生的血小板回收率略高于111In，T1/2也更长；使用血小板沉淀时未观察到差异。当研究储存血小板时，51Cr的T1/2和平均寿命（MLS）比111In显著更长。对于用于计算MLS的所有数学模型，以及使用全血样本和血小板沉淀时，这种差异都存在。结果表明，MLS的估计也高度依赖于血液采样和曲线拟合技术。与包含所有数据点的计算相比，排除初始数据点的计算得出的MLS始终更长（P<0.0001）。此外，当所有存活研究汇总在一起时，使用血小板沉淀的计算得出的血小板MLS比使用全血样本的计算显著更短（P<0.001）。结论是，51Cr和111In作为新鲜和储存血小板的放射性标记都是可以接受的。然而，储存血小板的活力似乎可能受标记选择的影响，在双示踪实验中同时使用这些同位素时必须谨慎。此外，我们的结果表明，需要对血液样本和实验数据进行精心标准化处理，以便能够在不同实验室之间比较结果。
