| (A) Cytotoxicity of mitomycin C (MMC). Phase-contrast micrographs showing the general morphology of control (A1) and MMC-treated mESC colonies (A2--4). Cell death induced by treatment with increasing MMC concentrations for 12 h (A5) was measured by flow cytometry as the percentage of caspase 3 positive cells. At 1 µg/mL, the effect of MMC was not significant (n = 3). (B) Assessment of neural differentiation in vitro: after 14 days of co-culture onto meningeal cells, most GFP-mESCs (green) pre-

Tumorigenicity assay in nude mice ...

(A) Photograph of the hindlimbs from a nude mouse 12 weeks after intramuscular injection of 500,000 mitomycin-treated (right) and untreated (left) mESCs. In all six animals tested, the right limbs were normal and the left limbs displayed large tumors. (B) In vivo MRI scans, coronal plane, proton density sequence, showing teratoma formation in the left limb, as opposed to the right limb (which received mitomycin-treated mESCs) of the same mouse. (C) In vivo MRI scans, axial plane, T1-weighted seq

Transplantation of fully undiffer...

(A) Survival curve of control and transplanted 6-OHDA-lesioned mice: 4 weeks after 6-OHDA injection in the striatum, mice were injected at the same stereotaxic coordinates with culture medium (lesion-control, n = 8), untreated mESCs (mESC, n = 8), or mitomycin-treated mESCs (MMCmESC, n = 12). (B,C) In vivo brain MRI, coronal plane, T1-weighted sequence, prior to (left-hand panel) and after (right-hand panels) gadolinium injection evidencing striatal tumor 4 weeks after transplantation of untreat