Figure 4. Sections of human retina immunocytochemically labeled for GH and dying cells. A: A section from a 74 year-old male labeled with DAPI (blue) for nuclei, growth hormone (GH) antiserum (red; asterisk); and TUNEL (green) for apoptotic nuclei. B: Another section from the same individual, labeled in the same way as A. C: A section from an 81 year-old male, labeled in the same way as A. D: A section from a 69 year-old male, labeled in the same way as A. With respect to cells in the ganglion cell layer (GCL), in the merged images, non-apoptotic and GH-positive nuclei appear red (asterisks) and correspond to nuclei numbered: A 5, B 2, C 1, D 2, and D 4. Apoptotic and GH-negative nuclei A 2, A 4, B 1, B 4, B 5, C 2, D 1, and D 3, appear blue-green. Non-apoptotic and GH-negative nuclei A 1, A 3, and B 3 appear blue. Abbreviations: inner nuclear layer (INL); outer nuclear layer (ONL). Scale bar equals 20 μm.