Reflection contrast microscopy for high resolution detection of H-3-estradiol in ultrathin sections of human stratum corneum

A single autoradiographical method for light and electron microscopy (LM an d EM) is presented. Human skin, containing H-3-estradiol (H-3-E2) after an in vitro permeation experiment, was processed via a non-extractive tissue p reparation protocol, comprising cryo-fixation, freeze-drying, osmium tetrox ide vapor fixation, and Spurr resin embedding. Semithin sections were proce ssed for LM autoradiography, while ultrathin sections were processed both f or high-resolution LM and EM autoradiography. The autoradiographs were visu alized by bright-field microscopy (BFM), reflection contrast microscopy (RC M), and transmission electron microscopy to evaluate the potentials of RCM visualization in high-resolution LM autoradiography. RCM visualization of u ltrathin vs. semithin resin sections showed an improved stratum corneum mor phology. Histological staining was superfluous. The localization of H-3-E2 in human stratum corneum using high-resolution LM autoradiography and RCM w as as accurate as with high-resolution EM autoradiography. Microsc. Res, Te ch, 47:286-290, 1999. (C) 1999 Wiley-Liss, Inc.