Macromolecular charge and cellular surface charge in adhesion, ingestion, and blood vessel leakage.
To get reliable information about the role of charged groups of tissue components on the integrity of blood circulation, the staining and perfusion experiments of rat organs with cationic (cacodylate iron colloid) and anionic iron colloid (chondroitin iron colloid) particles were carried out. These cationic and anionic iron colloid particles are stable in a wide range of pH's. Dissociation curves of several tissue components at varied pH levels were observed for the analysis of the results obtained by histochemical observations and perfusion experiments. The results indicated that all the intra- and extracellular spaces of living tissues are surrounded by the ionized anionic groups. No ionized cationic groups were found except on the macrophage surface. The cationic iron colloid particles perfused into organs through vessels adhered to the endothelial cell surface inducing the swelling of the cells. The cationic particles invaded into surrounding tissues passing through the damaged endothelial layer, but plasma protein leakage did not occur being prevented by the newly formed fibrin-fibrinogen lining. The anionic iron colloid particles introduced into vessels did not adhere to blood vessel walls but were taken by reticuloendothelial cells or macrophages. The importance of the ionized anionic groups of proteins on the endothelial cell surface and surrounding tissues for the integrity of blood vessel function was stressed.