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. Author manuscript; available in PMC: 2011 Nov 1.
Published in final edited form as: Clin Biochem. 2010 Aug 14;43(16-17):1269–1277. doi: 10.1016/j.clinbiochem.2010.07.027

Figure 5.

Figure 5

An example of the use of phenotypic phase plane analysis in a study of drug resistance HT29. The observed m1 (oxidative pentose pathway) to m2 (non-oxidative pentose pathway) of cell treated with different combination of drugs are plotted (from Ramos-Montoya et al. [53] with permission). Point #1 is the “control” phenotype of untreated cells; phenotype of oxythiamine (OT) treatment, point #2; dehydroepiandrosterone (DHEA) treatment, point #3 and methotrexate (MTX) treatment, point #4. Phenotypes of the combined treatment are point #5 combined OT+DHEA treatment; point #6 and #7 are for (OT+MTX) and (DHEA+MTX); and point #8, treatment with (OT+DHEA+MTX). Superimposing cell viability on the control phenotype vector creates a new viability axis. The isoclines are lines connecting the degree of cell viability to the metabolic phenotype characterized by (m1, m2).