An adherent monolayer culture of bovine pulmonary artery endothelial cells was labeled for the cytoskeletal filamentous actin and intracellular mitochondrial networks with Alexa Fluor 488 conjugated to phalloidin and MitoTracker Red CMXRos, respectively. Cell nuclei were counterstained with a carbocyanine monomer with long-wavelength red fluorescence, TO-PRO-3 (pseudocolored cyan). Images were recorded with a 60x oil immersion objective using a zoom factor of 1.5 and sequential scanning with the 488-nanometer spectral line of an argon-ion laser, the 543-nanometer line from a green helium-neon laser, and the 633-nanometer line of a red helium-neon laser. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles unless otherwise noted above.