The time course of neuropathological events induced by needlestick injury.

Columns 1–5: The expression of Aβ, APP and hyperphosphorylated tau in neural cells along the flanks of the track was upregulated quickly and transiently. The appearance of oligomeric Aβ in neural cells along the flanks, and along the track (perhaps extracellular) is similarly rapid and transient.
Columns 6, 7: The migration of glia to the site and/or proliferation of glia at the site developed more gradually and continued to the 30 d timepoint.
Columns 8–10: The death of cells (TUNEL-labelled cells averaged to the whole nearest number) began rapidly, and declined to baseline levels at 19 d. The loss of neuronal nuclei and of synaptophysin labels in axon terminals was detected more slowly, but persisted to 30 d.
Column 11: The Perls (Prussian blue) reaction for haem was positive early. Haem-positive deposits increased in prominence to day 14 and persisted to the 30 d time point.
Column 12: Fluorescent deposits, shown in several cases to be 4G8+ and hyperphosphorylated tau+, were detected at 7 d and grew in prominence to 30 d.