Image courtesy of Wikimedia Commons.
Luxol fast blue (LFB) stains are used to identify myelin in nervous tissue. The image demonstrates a loss of myelinated fibers at the basis pontis in the brainstem. This staining technique takes advantage of a simple acid-base reaction. LFB is a sulfonated copper phthalocyanine dye. Tissue sections are stained with the LFB solution to allow the base of the dye to exchange with the base of the myelin proteolipid, resulting in a dark blue precipitate. The excess dye is removed with 95% ethanol, then the tissue section is differentiated in lithium carbonate and 70% ethanol until the gray matter is colorless. The white matter will be blue to blue-green.