Figure 11.

Rat embryo fibroblasts labeled with ¹⁴C-thymidine. Fibroblasts were cultured on silicon chips, deprived of serum for 24 h and pulsed with serum and 19 nmol ¹⁴C-thymidine/ml (1 mCi/ml). (a,b,c) Simultaneous quantitative mass images of a fibroblast at (a) ¹²C¹⁵N^- (grayscale); (b) ¹⁴C^- (pseudo-color); (c) overlay of the ¹⁴C^- and ¹²C¹⁵N^- images. Field: 50 × 26 μm; acquisition time 14 h. (d,e) Simultaneous quantitative mass images of a control rat embryo fibroblast at (a) ¹²C¹⁵N^-; (b) ¹⁴C^-. Field: 50 × 41 μm; acquisition time 2 h.