The number of labeled cells in each density fraction as a function of time after re-infusion.

At each time shown, a blood sample was separated into 6 density fractions, and the number of total cells and the percentage of labeled cells in each fraction was determined. From these values, the number of labeled cells in each fraction was calculated, on the basis of a total of 1 million cells in the original blood sample. Note that the y-axis scales vary for the 3 studies.