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Biomedical subjects

M P Harri

Publications and source records attributed to M P Harri.

14 recordsLinked to original sources
PubMed1991

Altered tissue metabolism of progesterone in pregnancy gingivitis and granuloma.

The metabolism of progesterone may play a special role in the gingival physiology. The lower the metabolism the higher its hormonal activity in the tissue. In healthy human gingiva, progesterone is metabolized only partially and is therefore in an active form. In the present study, gingival samples from pregnancy gingivitis (n = 1) and granulomas (n = 4) were studied histologically and biochemically. All samples were homogenized and then incubated with [4-14C]-progesterone and NADPH for 2 h at pH 7.4 and 37 degrees C. The metabolites were separated and characterized with column, solvent and thin-layer chromatographies as well as radioautography and quantified with liquid scintillation counting. The results showed low metabolism of progesterone, indicating active hormonal function as in healthy gingiva. It is suggested that progesterone functions as an immunosuppressant in the gingival tissues of pregnant women, preventing the rapid acute-type of inflammatory reaction against plaque, but allowing an increased chronic-type of tissue reaction, resulting clinically in an exaggerated appearance of inflammation.

5-alpha-Dihydroprogesterone↗
PubMed1990

Metabolism of progesterone and testosterone by Bacillus cereus strain Socransky 67 and Streptococcus mutans strain Ingbritt.

Bacillus cereus strain Socransky 67 and Streptococcus mutans strain Ingbritt were grown overnight in complex medium and then in fresh medium flasks for 5 h. The bacterial cells in the medium were centrifuged and resuspended; 4-14C-progesterone or 4-14C-testosterone was added, and the samples were incubated for 2 h at 37 degrees C in a shaking water bath. The metabolites were analyzed with column and thin layer chromatography and radioautography and quantified by liquid scintillation counting. On the basis of the metabolites found it was concluded that B. cereus strain Socransky 67 contains 5 alpha-steroid hydrogenase, and 3 beta-, 17 beta- and 20 alpha-hydroxysteroid dehydrogenases and probably also steroid hydroxylases, and that S. mutans strain Ingbritt contains 5 alpha- and 5 beta-steroid hydrogenases, and 3 alpha-, 17 beta- and 20 alpha-hydroxysteroid dehydrogenases. The metabolic activity of B. cereus is several times higher than that of S. mutans. We suggest that the greater ability of B. cereus to metabolize progesterone and testosterone is probably due to its growth milieu in the gingival sulcus, where it is nearer to the gingival tissue.

Bacillus cereus↗
PubMed1986

Role of granulation tissue and fibroblasts in gingival testosterone metabolism in the rat in vitro.

The metabolism of testosterone by experimental granulation tissue, fibroblasts and the oral mucosa of rats of both sexes was studied. The experimental granulation tissue was produced by implanting viscose-cellulose sponges beneath the dorsal skin of female and male rats for 21 days. The granuloma capsules, fibroblasts in the sponges and the oral mucosae were homogenated. Mitochondrial, microsomal and soluble fractions were incubated with [4-14C]testosterone and NADPH for 30 min at pH 7.4 and 37 degrees C. The metabolites were identified with column and TLC and radioautography and quantified with liquid scintillation counting. The experimental granulation tissue and fibroblasts of both sexes showed less activity in metabolizing testosterone than the gingival tissue. The tissues were shown to contain 3 alpha-, 3 beta- and 17 beta-hydroxysteroid dehydrogenase and 5 alpha- and 5 beta-steroid hydrogenase activities. The activities of the enzymes in the oral mucosae were higher than in the experimental granulation tissue and fibroblasts.

Animals↗