Figure 3: Effect of i.p. sodium bicarbonate administration on cathepsin activity-related fluorescence in mouse xenografts. (a) Cathepsin activity in tumor bearing mice ( ) expressed as a percentage of the fluorescence taken prior to injecting 1 mL of sodium bicarbonate (1 M) or 1 mL of PBS. The change in fluorescence in PBS-treated mice was not statistically significant ( ). The mean 43.7% reduction in fluorescence of the sodium bicarbonate-treated group was statistically significant (* ). (b) Representative images comparing a PBS-treated mouse to a sodium bicarbonate-treated mouse.