Autologous Bone Marrow Transplantation - Blog Science Connections

754 Merocyanine 540 Marrow Decontamination
clonogenic cells added/well
Figure 1. Results obtained from limiting dilution analysis of bone marrow mononuclear
cells contaminated with 15% of CCRF-SB lymphoblasts and treated with mafosfamide
(AZ) alone or mafosfamide and merocyanine 540 (MC). The proportion of nonresponding
wells is plotted against the number of clonogenic cells added to each well containing 10 4
purged mixture cells (see note to Table 1). The lines of best fit, as determined by the
maximum likelihood regression analysis, x intercept values, and confidence limits (not
shown) on the population regression line were originated by a MINUIT computer program
in a VAX-750 computer.
photosensitization with MC-540 75% of these cells were still present (Fig 2).
Exposure of marrow cell suspensions to both agents, but in reverse sequence,
again caused a 50% CFCI-S inhibition.
DISCUSSION
It is assumed that the clonogenic cells are distributed randomly among the
culture wells, according to the Poisson probability distribution; hence, the 0
term of the Poisson equation will indicate that the proportion of negative wells
(i.e., ones in which no residual clonogenic cells remain after purging) is a
negative logarithmic function of the number of leukemic cells added to each
well. A regression line of best fit was established by the method of maximum
likelihood to enumerate residual clonogenic cells remaining in the suspension
after MC-540 photosensitization; these can be calculated as the x intercept of
the maximum likelihood regression line.