抄録
Positively charged colloidal gold (cationic colloidal gold) stains negatively charged areas (anionic sites) on histological sections. Specimens embedded in hydrophilic resins are especially suitable for the precise localization of anionic sites with cationic gold in post-embedding method. Enzyme digestion on the sections embedded in hydrophilic resins before the staining with cationic gold enabled us to identify the molecules such as sialic acid, chondroitin sulfate, and heparan sulfate which cause anionic charge. Studies using cationic colloidal gold have been published from various fields of biology and medicine. In the kidney, glomerular basement membranes and glycocalyx of epithelial cells show anionic sites and these negative charges are thought to play important roles in the selective permeability in the glomerulus. Distributions of anionic sites in the glomerular basement membranes and epithelial cells are altered in diseases and in experimentally induced nephropathy. My laboratory has studied the distribution and enzyme susceptibility of anionic sites in human sweat glands, epidermis, and skin tumors. Cationic gold stains eccrine and apocrine sweat glands in a different manner. This would be helpful for an accurate diagnosis of sweat gland tumors. Data so far obtained suggest cationic colloidal gold is a useful tool to study structures and functions of cells and tissues with histochemical methods.
