Intracerebral microdialysis data: brain interstitial 5-FC and 5-FU concentrations. A. Average brain interstitial 5-FC and 5-FU concentrations from patients on dose levels 1 (N=4), 2 (N=2) and 3 (N=3). Dose escalation was: level 1, 10 million CD-NSCs + 75 mg/kg/day 5-FC ; level 2, 10 million CD-NSCs + 150 mg/kg/day 5-FC and level 3, 50 million CD-NSCs + 150 mg/kg/day 5-FC. B. Intracerebral microdialysis data from a single patient on dose level 1 demonstrating the ability of the NSCs to convert 5-FC to 5-FU in the brain throughout the 7-day course of oral 5-FC. In this patient, no 5-FU was detected in the plasma, indicating that all of the 5-FU measured in the brain came from NSC-mediated conversion of 5-FC to 5-FU.