Calcium binding by normal human saliva

Bacterial agglutinins in rat salivary glands: effect of glandular stimulation and calcium dependency

The secretory pattern of salivary, bacterial agglutinins was studied in the rat. The three major salivary glands were cannulated bilaterally and their secretions collected separately after parasympathomimetic and sympathetic stimulation. The bacterial aggregating activity of the secretions was tested against four strains of bacteria indigenous to the rat. Agglutinin activity was demonstrated in both parasympathomimetic and sympathetic secretions. The parotid glands tended to show the highest total output of agglutinins, with the highest titers found in parotid saliva on sympathetic stimulation. In submandibular and, particularly, parotid saliva, titers tended to increase when stimulation with pilocarpine was followed by sympathetic stimulation. In contrast, titer in sublingual saliva tended to decrease on sympathetic stimulation. When expressed as titer output per minute, sympathetic parotid secretion showed the highest agglutinin activity. Agglutinin activity appeared unrelated to total protein or to duct-derived amidolytic activity. Titers of parotid or submandibular saliva were increased 5- to 10-fold by the presence of 3.3 mM CaCl2 in the reaction mixture. By contrast, the agglutinating activity of sublingual saliva on parasympathomimetic stimulation was unaffected by extraneous CaCl2. Measurements of Ca concentration in similarly obtained rat salivary secretions did not show patterns of Ca concentration that could be related to the varying sensitivity of the agglutinating activity to Ca.

Ionized calcium in body fluids

This article will review the methods currently available to the clinician and research worker for measuring the concentration of ionized calcium in various body fluids including whole blood, serum, plasma, urine, cerebrospinal fluid, milk, and synovial fluid. The methods to be reviewed are based on procedures involving bioluminescence, colorimetry and ion-selective electrodes. Emphasis will be given to the precision and, wherever possible, accuracy of each technique. Possible sources of error and interfering agents will be identified. Attention will be given to the recommended conditions for measuring ionized calcium in each body fluid. An assessment will be made of the theoretical and practical importance of measuring ionized calcium rather than total calcium and of its value in clinical medicine.

Observations on calcium-induced stability of salivary proteins in a lipid-extraction system

The system described for investigating the effects of small ions on macromolecules of saliva may be applied to other solutions and is amenable to manipulation in order to obtain more specific information. Studies using aqueous solutions of saliva fractions previously separated by gel filtration are being conducted with C/M solutions containing various bivalent cation chloride salts. Preliminary results from these current studies have demonstrated that when the proteins are stabilized they vary as a function of the cation used.

The stoichiometric solubility of calcium orthophosphates

On the assumption that the calcium orthophosphates dissolve stoichiometrically, the solubility of Hap, Fap, DCPD, OCP and TCP, as well as of CaCO3 and CaF2, have been calculated in terms of grams of solid phase per liter under equilibrium conditions. As exemplified in the text, these calculated solubilities facilitate the understanding of the complex behavior of the orthophosphates when in solution.