RespireRx Pharmaceuticals Inc (fka RSPI)

[striaterminalis]

It's a tough call, but I would agree it is most likely an artifact. I suspect that the discrimination between artifact and pathology would be glaringly obvious in the liver where there is much more experience in evaluating tox and where the cell types exhibit much less heterogeneity.

As for the evidence that all is normal in frozen sections (indicating that the signal appears after death and only in a certain fixation protocol), I was hoping to get some comments from the pathologist who posted earlier about what kinds of things are not as easily detected in frozen specimens. I would assume more is preserved and ultimately detectable in frozen sections if one is careful.

My original impression is that it had to be a tox effect, either through AMPA or off target pathways, that developed at the high doses. But now, it is starting to smell like it may be some blunder of a technician who made the same mistake while processing the high dose animals in parallel. Perhaps whatever mistake it was is easier to make in a rat than a monkey.