Fig. 1.

Time course of Aβ42 neuronal toxicity. (A) Neuronal cell count over a period of 66 h with medium alone (black), and upon addition of 3 μM Aβ42 in the absence (blue) and presence (red) of 0.7 μM GroEL. Error bars represent 1 SD. (B) Electron micrographs of Aβ42 as a function of time. Aβ42 was dissolved in 20 mM sodium phosphate buffer (pH 7.4) to a concentration of 300 μM and left for 3 d at 4 °C; the sample was then diluted to 3 μM (0 h) and incubated (in the absence of GroEL) at 37 °C for a total of 72 h.