Heavy metal staining in spinal motor neurons of MND patients (B, C and D from the same patient in Figure
). (A) Light AMG staining can be seen within the lipofuscin of this normal-appearing spinal motor neuron, but none is present in the non-pigmented cytoplasm. Bar = 7 μm. (B) and (C) Two shrunken spinal motor neurons with dense AMG staining, which is either obscuring the lipofuscin, or is free in the cytoplasm. Bars = 20 μm. (D) A shrunken spinal motor neuron contains dense heavy metal staining (closed arrow), whereas an adjacent normal-sized neuron (open arrow) contains no heavy metal staining, despite containing lipofuscin. Bar = 15 μm. AMG and hematoxylin.