Figure 3.

The effect of fixed-dose-rate versus bolus gemcitabine infusion with radiation on jejunal crypt survival. Mice were treated with 100-mg/kg gemcitabine through fixed-dose-rate infusion or with 500-mg/kg gemcitabine through bolus injection. Twenty-four hours after gemcitabine treatment, mice were given fractionated daily whole-body radiation (RT) (5 and 15 Gy at 1 or 3 Gy/day for 5 days, respectively) and were euthanized 66 hours after the fifth radiation dose. A section of the jejunum was fixed, and regenerating crypts were counted. Data are presented as the mean surviving fraction of crypts per circumference relative to the untreated control animals for each group (n = 3–4 animals per treatment group; four sections per animal were averaged to obtain a single value for each animal). There were statistically significant differences among the untreated, the radiation-treated, and the radiation- plus gemcitabine-treated groups (n = 3–4; P < .05); however, there was no significant difference between gemcitabine fixed-dose-rate infusion and bolus injection either in the absence or in the presence of 5- or 15-Gy radiation.