Light micrograph of amyloid substance around heart cells. The amyloid substance glows bright red under the Texas Red Filter (a filter that only lets through a specific wavelength of light when viewed with an immunofluorescence microscope). The amyloid substance is the cause of the disease amyloidosis. The amyloid deposits in a characteristic pattern around heart muscle cells, which are located in the dark round spaces in this photo. Magnification: 200x when printed at 10cm.