Immunofluorescence of 4-HNE adducts. Panels A (age-matched control) and B (STZ-diabetic) are images of 3-month neuronal cultures. Panels C (aged-matched control) and D (STZ-diabetic) are images of 6-month neuronal cultures. Neurons were stained and imaged using immunofluorescence for 4-HNE adducts. Images were captured on a Carl Zeiss LSM510 inverted confocal microscope with a 40x objective. The software program ImageJ 1.42 (available at http://rsbweb.nih.gov/ij/) was used to quantify both the intensity of fluorescence, and the total neurite area staining positive for 4-HNE adducts. Note in panel D the increased intensity of fluorescence expressed in the neurite swellings (white arrows).