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The in vivo kinetics of 111 In‐ and 51 Cr‐labelled platelets: a comparative study using both stored and fresh platelets
Author(s) -
Wadenvik Hans,
Kutti Jack
Publication year - 1991
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1991.tb04482.x
Subject(s) - platelet , in vivo , pellets , kinetics , chemistry , whole blood , nuclear medicine , surgery , medicine , materials science , biology , physics , microbiology and biotechnology , quantum mechanics , composite material
Summary The in vivo kinetics of simultaneously injected 51 Cr‐ and 111 ‐In‐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°C; the disappearance of platelet‐bound radioactivity was measured on whole blood samples as well as platelet pellets. Compared to 111 In, the labelling efficiency was notably lower for 51 Cr, and a higher amount of 51 Cr 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. 51 Cr yielded a slightly higher platelet recovery and longer T 1/2 than 111 In, when whole blood samples were used for calculations; no differences were seen when using platelet pellets. When stored platelets were studied, 51 Cr gave significantly longer T 1/2 and mean life‐span (MLS) than did 111 In. 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. Calculations, in which the initial data points were excluded, gave consistently longer MLS ( P <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 <0.001) shorter platelet MLS than calculations using whole blood samples. It is concluded that both 51 Cr and 111 In 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 inter‐laboratory comparisons of the results.