A, Histogram showing the effect of explanted encapsulated cells on the activity of ChAT on spinal motoneuron cultures. Control wells (negative control) received no trophic factor (100%). Two wells per series received 20 ng/ml rat recombinant GDNF (positive control). All counts were normalized by the number of counts in the negative control. The capsules containing BHK-GDNF cells significantly increased the ChAT activity of the cultures. *p < 0.03 (vs control); **p < 0.0001 (vs control); #p< 0.0002 (vs BHK), ANOVA. Values are mean ± SEM.B, Micrograph showing encapsulated BHK-GDNF cells on explantation at 2 weeks. Note the good viability of the transplanted cells. Mem, Membrane. Scale bar, 100 μm.