title: Epi-polarization and incident light microscopy readily resolve an autoradiographic or heavy metal label from an obscuring background or second label.
abstract: Difficulty encountered in resolving grains of exposed photographic emulsion in autoradiographs of the densely melanized retinal pigment epithelium was solved by using epi-polarized or incident light microscopy. The apparatus used included a metallurgical illuminator specifically designed for epi-polarization microscopy or, as a less expensive but only slightly less effective alternative, a modified fluorescence illuminator. The black melanin granules absorb incident light (as they do in vivo) while the silver grains reflect it producing a "darkfield-like" representation. Brightfield and darkfield-like images can be alternated easily and quickly, or both can be viewed simultaneously. Epi-polarization microscopy has wider application in resolving a reflective label over any opaque background staining or dark second label.
authors.affiliation: Department of Anatomy, University of Sydney, NSW, Australia.
authors.forename: D H
authors.initials: DH
authors.lastname: Rapaport
authors.forename: K G
authors.initials: KG
authors.lastname: Herman
authors.forename: M M
authors.initials: MM
authors.lastname: LaVail
mesh_terms: D000818:Animals; D001345:Autoradiography / Q000379:methods*; D006651:Histocytochemistry; D008027:Light; D008670:Metals / Q000032:analysis*; D008853:Microscopy / Q000379:methods*; D008859:Microscopy, Polarization / Q000379:methods*; D009893:Opossums / Q000033:anatomy & histology*; D010487:Periaqueductal Gray / Q000033:anatomy & histology; D012160:Retina / Q000033:anatomy & histology / Q000166:cytology; D012165:Retinal Ganglion Cells / Q000648:ultrastructure
chemical_list: D008670:Metals