Fixation, embedding, and sectioning of tissues, embryos, and single cells.

This unit describes selected methods for fixing and sectioning various forms of biological materials ranging from tissues to single cells. Sections prepared according to these protocols can then be used to examine cell and tissue morphology and in studies involving in situ hybridization, immunohistochemistry, and enzyme histochemistry. The basic protocol describes how tissues and embryos can be prepared for sectioning by fixing in paraformaldehyde followed by embedding in wax, while an alternate protocol describes fixation of suspended or cultured cells. Two support protocols cover preserving and fixing organs by perfusion of whole animals with paraformaldehyde and a procedure for sectioning wax blocks of fixed tissue, plus the subsequent mounting of sections onto prepared or "subbed" glass slides.