A methacrylate embedding technique for combined autoradiography and acid phosphatase histochemistry

A method is described that enables the simultaneous application of autoradiography and histochemistry in tissue sections prepared using a hydroxyethyl methacrylate (HEMA) embedding medium. A novel fixation regime, using a 1:9 v/v mixture of acetone and 10% neutral buffered formalin, improves section quality, histological staining and reduces tissue and cell shrinkage. The combined localization of [6-3H] thymidine incorporation and acid phosphatase in mouse thymus, duodenum, human stomach biopsy, earthworm and Walker tumour is described and counts of macrophages, phagocytosed cells, pyknotic cells, mitotic figures and thymidine-incorporating cells from young and old mouse thymus are presented.