75Se-methionine platelet survival studies: a proposal for a mathematical correction of the curve.

We studied platelet survival in 14 cardiac before heart valve replacement using 75Se-methionine 'cohort label'. The temporal variation of plasma and platelet activity was plotted by a continuous curve by means of a computerized interaction of the single points. Then we computed the plasmatic radioactivity fraction used daily for thrombopoiesis and made a subtraction of this aliquot from a experimental activity in the catabolic phase of the slope. Platelet life span obtained after this 'correction' is comparable with the values of random label using 51Cr.