Figure 6

After 72 hr exposure to human sera at 37°C, DA levels were assessed in cultures of n-butyrate-differentiated MN9D neuronal cells (4 × 10⁴ cells/ml). Black bars represent DA values upon exposure to a pool of 8 control sera; gray bars represent values upon exposure to a pool of 19 sera from IPD patients. Results are reported as both (A) ng/well and (B) ng/mg protein. Bars represent the mean and standard error of the mean for three individual wells. *P < 0.05 compared to control sera.