Fig. 2.

Hemoglobin localization in control and ALS spinal cord. Immunohistochemical staining of hemoglobin extravasation in cervical white matter from control (a–c) or ALS (d–f) spinal cord. Hemoglobin immunoreactivity (red) and lectin-positive vessels (green) are shown with a Hoechst nuclear counterstain (blue). Scale bars = 50 µm. Representative images of full spinal cord sections from the cervical level of a control case with no hemoglobin leakage (g), the thoracic level of an ALS case with white matter hemoglobin leakage (h), and the lumbar level of an ALS case with gray matter hemoglobin leakage (i) are shown. Dashed lines show gray matter boundary; scale bar = 1 mm. Occasional hemoglobin staining of SMI-32-positive anterior horn motor neurons was also observed (j–m). White arrowhead indicates a SMI-32-positive hemoglobin-positive motor neuron, where the red arrow indicates an SMI-32-positive hemoglobin-negative motor neuron. Scale bars = 50 µm