Figure 3
From: Decreased functional activity of multidrug resistance protein in primary colorectal cancer
Calculating the MAF-values of viable epithelial cells. The functional activity of MDR1 and MRP1 transporters are calculated with FL2 (calcein fluorescence) histograms showing the impact of the various MDR inhibitors on the mean fluorescence intensity shift. The total inhibitor (Verapamil blocks MDR1 and MRP1) histogram and the MRP1 inhibitor (MK-571) histogram are compared to the control histogram (HBSS, in the middle). In this sample no shift could have been seen with either inhibitor indicating low MDR1 and MRP1 functional activity. Mathematic formula was the following: MAFTotal = 100 × (FVerapamil – FHBSS)/FVerapamil; MAFMRP1 = 100 × (FMK571 – FHBSS)/FVerapamil; MAFMDR1 = MAFTotal – MAFMRP1. Where F means the mean Calcein-fluorescence values determined on FL2 in the different samples individually. Here FVerapamil (Total MDR Inhibitor) = 736, FHBSS (Control) = 730, FMK571 (MRP1 inhibitor) = 737; which equals MAFTotal = 1, MAFMRP1 = 1, MAFMDR1 = 0