Figure 1.

Characteristic staining patterns for Epo and CD131 in the medulla of the brainstem. A. Strong intravascular serum staining for erythropoietin (Epo, arrow). A range of staining intensities for Epo in the cytoplasm of neurons. B. Immunostaining for Epo in the nucleus and cytoplasm of neurons. Neurons and small vessels without Epo staining can be observed in this field. C. Two adjacent vessel showing strong endothelial and lighter pericyte/smooth muscle cell labelling for Epo. Glial cells with Epo labelling of processes are also shown (arrows). D. High power image of a pial vessel showing endothelial and pericyte/smooth muscle labelling. E. High power image of a parenchymal vessel with sequestered malaria parasites and Epo labelling of endothelial cells. F. Immunolabelling for CD131 on large and small (see insert) vessels. Labelling is found on both endothelial cells and pericytes/smooth muscle cells. The large vessel shows perivascular haemorrhage and oedema. G. Neurons from a control case with ischaemia showing immunolabelling for CD131. Staining is cytoplasmic with enhancement at the plasma membrane (see insert). Scale bars: A-C, F, G, 50 μm; D, 25 μm; E, 10 μm.