Kristen Helgeland

Uptake and Retention of Alkali-Soluble and Alkali-Insoluble Fluoride in Sound Enamel in vivo after Mouthrinses with 0.05% or 0.2% NaF

The uptake and retention of alkali-soluble and alkali-insoluble (fluorapatite) fluoride in human teeth in vivo was investigated in a group of orthodontic patients from whom two premolars were to be extracted. Daily mouthrinses with 0.05 % NaF for 2 weeks increased the fluoride content of the outer enamel layer (≈ 5 μm) by 15.9%. One rinse with 0.2% NaFincreased the fluoride content by 5.8%. Amajor part of the fluoride deposited was soluble in alkali. No significant uptake of fluoride in a second enamel layer (≈5 μm) was found. It is suggested that the alkali-soluble fraction of fluoride, representing the major part of the fluoride retentate, might serve as a significant reservoir of fluoride, and is perhaps a factor of prime importants concerning its cariostatic effect.

Copper and zinc in human serum in Norway

Serum samples were collected from the adult population, age groups from 20 to 54 years, in 11 different Norwegian municipalities and analysed for zinc and copper by atomic absorption spectroscopy. Significant differences were found between several of the municipalities when the mean concentration of zinc in serum in 200 randomized samples were compared, with only two municipalities being different for copper. The values for zinc ranged from 13.8 to 18.3 μmol/1 and copper varied between 16.3 and 19.2 μmol/1. An age related increase in the copper concentration was evident in the male population, and age-adjusted means showed a slight, but significantly higher serum copper concentration in females (18.4μmol/l) than in males (16.5 μmol/1). For zinc the opposite sex-relationship was indicated with the highest values in males, 15.8 compared to 15.1 μmol/1 in serum from females. No significant correlations were found between the concentrations of zinc and copper in serum. In all age groups of women, however, a s...

Highly increased numbers of leukocytes in inflamed gingiva from patients with HIV infection

Background HIV infection increases susceptibility for marginal periodontitis, with horizontal and rapid loss of periodontal soft tissues and alveolar bone. Objectives To examine whether numbers, distribution and some properties of mast cells, neutrophils and macrophages are normal in chronically inflamed gingiva of HIV-positive patients. Methods Gingival biopsies were stained for mast cell tryptase and chymase, neutrophil elastase, CD68, human transforming growth factor β1, HLA-DR, FcγRI, FcγRII and FcγRIII and calprotectin. Results Patients at all stages of HIV infection showed radically increased numbers of mast cells and neutrophils throughout the connective tissue, and of macrophages below the oral gingival epithelium (P < 0.05). Conclusion HIV infection is associated with increased numbers of mast cells, macrophages and neutrophils in the chronic periodontal lesion. This may predispose for tissue destruction through the release of inflammatory mediators and effector molecules. The unusually heavy cell infiltrate throughout the gingival connective tissue may contribute to the diverging pattern of periodontal tissue loss in HIV-positive patients.

Signal transduction and gene transcription induced by TFF3 in oral keratinocytes

Trefoil factor family 3 (TFF3) is secreted in saliva. The peptide improves the mechanical and chemical resistance of mucins, and it may act as a motility signal for oral keratinocytes during wound healing. This study aimed to identify novel functions of TFF3 in oral keratinocytes. To achieve this, we used phosphoprotein and messenger RNA (mRNA) arrays to compare TFF3-treated and untreated oral keratinocytes. Analysis of the phosphoprotein array indicated that TFF3 signals through the mitogen-activated protein kinases (MAPKs) c-Jun N-terminal kinase (JNK), p38, and extracellular signal-regulated kinase (ERK1/2), and through the phosphoinositide 3-kinase (PI3K)/protein kinase B (PKB) pathway. Microarray analysis of mRNA showed that TFF3 stimulation induced changes in the expression of genes functionally related to cell death/survival, cell growth and proliferation, and cell movement. The reverse transcription-polymerase chain reaction (RT-PCR) results indicated that the transcription of some immediate-early genes (IEGs) was downregulated, whereas the IEGs FBJ osteosarkoma oncogene (FOS) and C-MYC binding protein (MYCBP2) were transiently upregulated by TFF3 stimulation. Together, the results of the arrays indicate that TFF3 is a modifying factor in pathways regulating cell survival, cell growth and proliferation, and cell migration of oral keratinocytes. Trefoil factor family 3 may therefore promote oral wound healing and it should be considered for the treatment of oral ulcerating diseases, or of other diseases.

THE GINGIVAL PLASMA CELL INFILTRATE IN RENAL TRANSPLANT PATIENTS ON AN IMMUNOSUPPRESSIVE REGIMEN

Treatment with immunosuppressive agents inhibits gingival inflammation and progression of periodontitis in humans. We examined the numbers and the isotype distribution of immunoglobulin-producing plasma cells by immunohistochemistry in gingival specimens taken from renal transplant transplant recipients receiving immunosuppressive agents (IS), and from otherwise comparable systemically healthy patients. The immunosuppressed patient group had significantly (P< 0.05) fewer IgG-, IgA-, IgG1-, IgG2-, and IgG4-producing plasma cells in the connective tissue adjacent to the pocket epithelium. The reduced numbers of such patents with quiescent periodontal disease support the contention that high counts of plasma cells are indicative of more severe disease.

Effects of cadmium acetate and sodium selenite on mucociliary functions and adenosine triphosphate content in mouse trachea organ cultures

The effects of cadmium acetate and sodium selenite in mouse trachea organ culture have been studied separately and in combination. Ciliary activity, morphology, rate of total protein and glycoconjugate (i.e. glycoprotein and proteoglycan) synthesis/secretion and ATP content were investigated. Exposure to 10 microM cadmium acetate or 2000 microM sodium selenite resulted in a complete cessation of ciliary activity within 5 h. With cadmium acetate also a swelling of epithelial cells was observed. Sodium selenite (250-2000 microM) delayed by 2-3 h the inhibitory effect of cadmium acetate (5-20 microM) on ciliary activity. The rate of protein synthesis, as determined by incorporation of [3H]proline, was reduced by 13% and 44% at exposure for 4 h at 37 degrees C to 250 microM and 500 microM sodium selenite respectively, the effect being partly abolished by cadmium acetate. With 5 microM and 10 microM cadmium acetate the rate of glycoconjugate synthesis, as measured by incorporation of [3H]glucosamine, increased by 50% and 69%, respectively, after incubation for 4 h. This increase was partly reduced by sodium selenite. Neither cadmium acetate nor sodium selenite had any effect on the rate of total protein or glycoconjugate secretion. The ATP content in trachea rings was reduced by 48% and 54% after incubation for 4 h with 250 microM and 500 microM sodium selenite, respectively. No significant effect of cadmium acetate was found on ATP content. An antagonistic effect of sodium selenite and cadmium acetate in mouse trachea organ culture is suggested from the present experiments.

Attachment of human gingival fibroblasts to planed root surfaces exposed to human plasma in vitro

We studied the effect of exposing planed dentin surfaces (DS) to human plasma on the attachment of human gingival fibroblasts (HGF) in vitro as compared with their attachment to citric-acid-demineralized DS. Sixty-six DS were prepared from root-planed roots of surgically extracted human third molars. In a pilot experiment 30 DS were demineralized in citric acid (pH 1.0 for 3 min), and each of 3 DS were placed in a culture dish and incubated with fresh plasma for 0, 10, or 30 sec, 1, 10, or 30 min, or 1, 1.5, 2, or 4h. In a second experiment, three culture dishes containing three DS each were assigned to each of four groups. These were untreated (control), incubated with plasma for 2h, acid-demineralized only, or acid-demineralized and then incubated with plasma for 2h. To each dish was added 0.2 X 10(6) HGF, and these were incubated for 2, 6, or 24 h. The unattached cells were then removed, and the DS fixed and processed for SEM. The results showed that exposing demineralized dentin surfaces to plasma causes the absorption of a coating layer, presumably of organic nature, as early as 30 sec after exposure. Acid-demineralized DS alone or together with plasma treatment enhanced both the attachment and the growth of HGF. However, treatment with plasma alone seemed to enhance the HGF attachment less than did acid demineralization alone.

Ion transport and cadmium-induced inhibition of ciliary activity and induction of swelling of epithelial cells in mouse trachea organ culture

Swelling of epithelial cells and reduction of ciliary activity in mouse trachea organ culture occurred after incubation for 4 h with a rather low concentration of cadmium acetate (10 microM). Specific inhibitors of ion transport (Na+, K+, Cl-) such as furosemide, amiloride and ouabain did not mimic, abolish or increase the toxic effects induced by cadmium acetate. Exposure to cadmium acetate had no significant effect on electrolyte uptake (22Na+ and 86Rb+). These results suggest that the swelling of epithelial cells induced by cadmium acetate is not due to an osmotic swelling from an accumulation of electrolytes. Ba2+, known to have several biological properties in common with Ca2+, and to influence basolateral K+ flux, counteracted the toxic effects of cadmium acetate, whereas a more rapid and extensive swelling occurred with cadmium acetate in a medium without Ca2+. No effect on the uptake of 109Cd2+ was found with barium chloride, whereas in a medium without Ca2+ the Cd2+ uptake increased by 47%. Trifluoperazine (100 microM), a drug which in vitro binds tightly to calmodulin, imitated the toxic effects of 10 microM cadmium acetate. The combination of 10 microM cadmium acetate and 100 microM trifluoperazine resulted in an additive toxic effect. A possible mechanism for the cadmium acetate-induced swelling and inhibition of ciliary activity could, thus, be a disturbance of the regulatory activity of calmodulin.

The role of nerve growth factor (NGF) and its precursor forms in oral wound healing

Nerve growth factor (NGF) and its different precursor forms are secreted into human saliva by salivary glands and are also produced by an array of cells in the tissues of the oral cavity. The major forms of NGF in human saliva are forms of pro-nerve growth factor (pro-NGF) and not mature NGF. The NGF receptors tropomyosin-related kinase A (TrkA) and p75 neurotrophin receptor (p75NTR) are widely expressed on cells in the soft tissues of the human oral cavity, including keratinocytes, endothelial cells, fibroblasts and leukocytes, and in ductal and acinar cells of all types of salivary glands. In vitro models show that NGF can contribute at most stages in the oral wound healing process: restitution, cell survival, apoptosis, cellular proliferation, inflammation, angiogenesis and tissue remodeling. NGF may therefore take part in the effective wound healing in the oral cavity that occurs with little scarring. As pro-NGF forms appear to be the major form of NGF in human saliva, efforts should be made to study its function, specifically in the process of wound healing. In addition, animal and clinical studies should be initiated to examine if topical application of pro-NGF or NGF can be a therapy for chronic oral ulcerations and wounds.

Editorial: Immune-mediated mucosal diseases: tales about battles lost and won

The following articles constitute the second part of the proceedings of the international conference ‘New Frontiers in Oral Immunological Diseases’, which was held in Lillehammer, Norway, 23–27 February 2001. The first series of articles (1–12) was published in the previous issue of Acta Odontologica Scandinavica, and the last series will appear in the next issue of the journal. The aim of the congress was to introduce new perspectives in oral immunological diseases through integration with non-oral fields. The present reviews address immune-mediated mucosal diseases.