imaging. (A) Skin was removed from an amputated arthritic foot in which thickness had increased by 29% (n = 6). High intensity of near-infrared emission was detected in the pseudo-colored image, thus validating that the fluorescence was due to cell death at the swollen ankle rather than to dye tracked externally on the foot. (B) Detection of apoptosis in portion of the associated inguinal lymph node. (C) Lack of emission in a deskinned arthritic limb from a mouse injected with the control dye (n = 3).