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Biomedical subjects

J Tenovuo

Publications and source records attributed to J Tenovuo.

At least 145 records · Page 8Linked to original sources
PubMed1980

Distribution and forms of iodine in human oral cavity.

Neither iodinated proteins nor iodinated, low-molecular weight compounds (e.g. iodinated tyrosine derivatives) could be detected in concentrated human salivary supernatant by using the Ce(SO4)2-method either directly or after thin-layer chromatography. Salivary sediment contained free I- ions, loosely bound iodine (released with saline) and strongly bound iodine (released with sonication, detergent and acid hydrolysis). A positive correlation between salivary and crevicular excretion of I- from plasma was observed. Thiocyanate ions, which competitively inhibit peroxidase-catalysed oxidation and iodination reactions and which are abundant in human saliva, possibly prevent the coupling of I- to protein in vivo although some human salivary proteins are very susceptible to iodination in vitro.

Dental Plaque↗
PubMed1980

Release of lysosomal hydrolases from bone explants affected by dental plaque.

Lysosomal hydrolases as indicators of plaque-induced bone resorption in tissue culture were studied. Fetal rat bones cultured in a synthetic medium containing sonicated and filtrated human dental plaque were used as bones to be resorbed. Acid phosphatase and beta-glucuronidase were found to be the most suitable enzymes for studying the degradation rate of bone cell lysosomes. When dental plaque is used as a resorbing agent, special attention has to be paid to the fact that plaque extract contains similar lysosomal hydrolase activity. Plaque hydrolases in the present study were quite stable in culture medium. No significant adsorption of enzymes by fetal rat bones occurred while remarkable adsorption by synthetic hydroxyapatite was found. The present results indicate that dental plaque is able to release lysosomal hydrolases from bone explants. This release corresponds to the degree of resorption measured by 45Ca release from bones.

Acid Phosphatase↗
PubMed1979

Formation of dityrosine by human salivary lactoperoxidase in vitro.

The study dealt with the formation of dityrosine - a cross-link in some proteins including collagen - by human salivary lactoperoxidase. Dityrosine formation was found at pH range 6.6 to 9.3 with maximum reaction velocity at pH 8.5. However, thiocyanate ions at physiological salivary concentrations inhibited dityrosine formation by 70 to 80 per cent compared with the optimum rate. The inhibition seemed to result from the competition of SCN ions and L-tyrosine for the same binding site on enzyme surface. The possibility of dityrosine cross-linking in vivo in human oral fluid seems to be limited compared with e.g. human milk or macaque saliva where the concentration of SCN ions is low but the activity of lactoperoxidase is considerably high.

Humans↗
PubMed1978

Application of a dehydrated test strip, HEMASTIX, for the assessment of gingivitis.

In order to develop a rapid and simple method based on chemical alterations in gingival pockets during inflammation, the HEMASTIX strips were used to record the degree of gingivitis. This dehydrated test strip records the presence of both hemoglobin derived from erythrocytes and myeloperoxidase from PMN-leukocytes. The intensity of the blue color that appeared and the amount of adsorbed fluid were recorded. The correlation of the Strip Index with Gingival Index was highly significant (P is less than 0.001) and with Gingival Bleeding Index significant (P is less than 0.01). When determined both from the left side of the upper jaw and from the Ramfjord teeth, the correlation between these two areas was highly significant (P is less than 0.001) in the case of Strip Index but only slightly significant (P is less than 0.05) with Gingival Index. According to the present results the Strip Index can be used for the assessment of biochemical changes in gingival pockets resulting from the development of gingivitis.

Adult↗
PubMed1978

Effect of peroral administration of xylitol on the oxidoreductase activity of human blood cells and certain chemical properties of saliva and serum.

The effect of xylitol on the activity of certain oxidoreductases of human granulocytes, lymphocytes, and erythrocytes was studied both in vivo and in vitro. The effect of xylitol consumption on certain chemical properties of serum and whole saliva was also investigated. Short-term peroral administration of 0.6 g xylitol or glucose per kg body weight and day had a similar effect on leucocyte peroxidase levels. 0.07-0.2 M xylitol and glucose did not differ in their effects on leucocyte peroxidase levels in vitro either. Peroral administration of xylitol increased the whole saliva lactoperoxidase levels compared to glucose administration, but the differences were not significant. The results suggested that although the consumption of xylitol may under certain circumstances increase the peroxidatic capacity of saliva, that of leucocytes is not significantly affected.

Administration, Oral↗
PubMed1977

Enzymically iodinated human salivary proteins. Fractionation and characterization by column chromatography and electrofocusing.

Human salivary proteins were enzymically iodinated by the 125I-lactoperoxidase system. The proteins were than subjected to DEAE-cellulose column chromatography, preparative column electrofocusing and thin-layer polyacrylamide-gel electrofocusing. The radioactivity in the resolved protein pools and bands was determined. Results show that salivary proteins differ in their susceptibility to iodination carried out by this enzymic method. Two major iodine-binding protein fractions were discovered: one behaved like serum albumin on electrofocusing and was most susceptible to iodination by lactoperoxidase, and other had pI characteristics similar to those of salivary amylase. The physiological significance of the iodination of salivary proteins, which can also take place in vivo, is discussed.

Chromatography, DEAE-Cellulose↗
PubMed1977

Enzymatic iodination of salivary proteins by the 125I-lactoperoxidase system.

Purified milk lactoperoxidase and endogenous human salivary peroxidase were used to label the proteins of whole mouth saliva with [125I]iodide. The proteins were then analyzed by isoelectric focusing or they were subjected to one-dimensional polyacrylamide gel electrophoresis at pH 8.4. The radioactivity of the resolved protein fractions was determined. There were three to four major and four to five minor areas of radioactivity which were carried together with more or less distinctive protein fractions. Amylase and albumin were shown to be the most effective in binding [125I]iodide. No significant differences were observed in the iodination patterns of salivary proteins iodinated in the presence of endogenous saliva peroxidase and those iodinated in the presence of added milk lactoperoxidase. Hydrogen peroxide was necessary for iodination to take place. The significance of iodoproteins and the role of salivary peroxidases in the nonthyroidal metabolism of iodine are discussed.

Albumins↗