Negative stained Transmission Electron Micrograph (TEM) of amyloid fibrils, abnormally folded proteins that are associated with many diseases, including Alzheimer's and Mad Cow Disease. Amyloids are aggregates of proteins that become folded into a shape that allows many copies of that protein to stick together forming fibrils. In the human body, amyloids may cause various diseases, as previously healthy proteins lose their normal physiological functions and form fibrous deposits in plaques around cells that disrupt the healthy function of tissues and organs. Such amyloids have been associated with more than 20 human diseases, known as amyloidosis, and may play a role in some neurodegenerative disorders. Magnification unknown.