[Levels of amino group nitrogen and imidazole compounds in human oral fluid]

The procedures of definition amino nitrogen (sum amino acids) and imidazole compounds in human oral fluid are described. Amino nitrogen were determined by the ninhydrin method modified by the authors, imidazole compounds by the Pauli test. A total of over 20 patients with the relatively good dental status were surveyed. The level of amino nitrogen showed noticeable fluctuations (2.01 +/- 1.24 mmol per ml of oral fluid), whereas the content of imidazole derivatives was more stable (0.71 +/- 0.19 mmol/ml). Oral fluid samples displayed an in vitro high proteolytic activity, which explains contradictory results in the determination of the levels of amino nitrogen.