[Sialic acids (brief review of the results obtained in 25 years)].

The main results obtained by the author and collaborators in 25 years' work about the type of sialic acid determined in some materials from the animal kingdom are summarized, with the respective references to the original papers and the indication of the reviews in which they have generally been quoted. The high number of publications on sialic acids from the time of their discovery reflects the increasing interest on these acids in areas such as their chemical composition (16 different sialic acids are now recognized), their distribution in Nature (a not yet well explained topic), their metabolism (which shows differences between bacteria and animal cells) and their biological roles, mainly as a part of glycoproteins and gangliosides (as receptors, markers of the cytoplasmic membrane, viscosity agents of the glycoproteins, life regulators of some substances, etc.).