Investigations to determine the optimum conditions for radiolabelling human platelets with99Tcmhyphen;hexamethyl propylene amine oxime lpar;99Tcmhyphen;HMhyphen;PAOrpar;

摘要

Summary99Tcmhyphen;hexamethyl propylene amine oxime lpar;99Tcmhyphen;HMhyphen;PAOrpar; has been evaluated as an agent to radiolabel human plateletsin vitro. The rate of uptake of this lipophilic complex, the effect of HMhyphen;PAO, plasma and platelet concentration were measured to determine the optimum conditions for radiolabelling platelets for shorthyphen;term clinical investigations of thromboses. The complex was made according to the manufacturer's instructions and immediately added to isolated plateletsin vitro. The rate of labelling was slower than for leucocytes, reaching a plateau after approximately 40 min at room temperature lpar;RTrpar;. Increasing the temperature to 37deg;C did not increase the labelling efficiency lpar;LErpar;. Addition of plasma to platelets at a cell concentration of 1times;1109mlhyphen;1reduced the LE from 66percnt; in saline to 52percnt; in 20percnt; ACDhyphen;plasma. However, increasing the platelet concentration from 5times;108to 2times;109mlhyphen;1, increased the LE from 9 to 76percnt; for platelets labelled in 20percnt; plasma for 30 min at RT. Thein vitrostability of the99Tcmin the labelled cells showed that 7percnt; of the radioactivity were immediately released from the platelets and a further 13percnt; were eluted during a 60 min incubation in plasma at 37deg;C. It has been concluded that incubation of platelets at RT with99Tcmhyphen;HMhyphen;PAO containing 80 mu;g mlhyphen;1HMhyphen;PAO at a cell concentration of 1times;109mlhyphen;1or greater, results in a high LE, with more than 85percnt; of the99Tcmbeing retained by the platelets during a 60 min incubation in plasma.