Figure 3.

Experimentally derived tumour and urine pHe measurements for bicarbonate-treated and control mice. (A) Imaging of the window chamber showing the tumour with abundant vascularisation. The pH measurements were taken along radial lines indicated in white. (B) Window chamber least-squares fit across all directions and with all tumours showing pHe distributions along radial lines for control untreated and bicarbonate-treated tumours. The horizontal axis represents the radial distance from the core of the tumour, with the tumour rim indicated by the vertical black line at ∼1.4 mm. Note the raised tumour pH in the buffered mouse and the acidic pH in the interior of the tumour, with a gradient leading out into the normal tissue. The mean (s.e.) pH is 7.0 (0.04) and 7.07 (0.03) for the untreated and treated tumours, respectively (reported in Robey et al (2009)). The pH is determined using fluorescence ratio imaging of SNARF-1 as described in Robey et al (2009). (C) Average urine pHe (vertical axis) for untreated (blue circles) and bicarbonate-treated (red squares) mice through time measured in days (horizontal axis). Measurements were taken at just before treatment (indicated as day 0) and then 6 h after treatment initiation (day 0.25), which already showed a significant rise in urine pHe for the treated mice. Bicarbonate-treated mice show a consistently elevated urine pHe. The mean pHe is shown (circle/square) with the mean±standard error indicated by a bar and vertical line. Figures (A and B) are adapted with permission from Cancer Research (Robey et al, 2009). The colour reproduction of this figure is available at the British Journal of Cancer online.