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The stable, water-soluble, and nonfluorescent FA-OMe can sense nitric oxide (NO) and form the intensely fluorescent product dA-FA-OMe via reductive deamination of the aromatic primary amine. The reaction is accompanied by a notable increase of the fluorescent quantum yield from 1.5 to 88.8%. The deamination mechanism of FA-OMe with NO was proposed in this study. The turn-on fluorescence signals were performed by suppression of photoinduced electron transfer (PeT), which was demonstrated by density functional theory (DFT) calculations of the components forming FA-OMe and dA-FA-OMe. Furthermore, FA-OMe showed water solubility and good stability at physiological pHs. Moreover, the selectivity study indicated that FA-OMe had high specificity for NO over other reactive oxygen/nitrogen species. In an endogenously generated NO detection study, increasing the incubation time of FA-OMe with lipopolysaccharide (LPS) pretreated Raw 264.7 murine macrophages could cause an enhanced fluorescence intensity image. In addition, a diffusion/localization cell imaging study showed that FA-OMe could be trapped in Raw 264.7 cells. These cell imaging results demonstrated that FA-OMe could be used as a turn-on fluorescent sensor for the detection of endogenously generated NO.

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HLA-A, B and DR antigen frequencies were determined in three groups of periodontally diagnosed subjects: 49 patients with rapidly progressive periodontitis, 40 elderly subjects with minimal disease (considered as a resistant group) and 30 young subjects with minimal disease. The relative risk for HLA-A9 (previously reported to be associated with periodontal disease) was 15.5. HLA-A9 was present in 36.7% of the patients and 2.5% of the resistant group. HLA-A10 showed a significantly increased incidence in the resistant group (30.0%) compared to a non-periodontally diagnosed control population (9.0%), and was absent from the patient group. These findings provide additional evidence for the involvement of HLA-A9 in susceptibility to periodontitis, and suggest that A10 may play a role in resistance to the disease.

The immunoglobulin class distribution of antibody to human collagen type I has been examined in sera and gingival extracts from patients with adult chronic periodontitis. Tissue extracts were made either by simple washing or ultrasonication. With either method, IgG and IgA antibodies to collagen were present in higher concentration in tissue extracts than in autologous serum when adjustment was made for dilution differences. No significant differences were found for IgM antibodies. Antibodies to human collagen type I are usually "natural antibodies" of the IgM class and, therefore, our findings suggest a class switch to IgG in inflamed gingivae, presumably due to prolonged antigenic stimulation.

Serum antibody levels to human collagen Type I were measured in 97 patients with periodontal disease (Russell Periodontal Index 1.0-7.0) and 57 control subjects (Periodontal Index less than 1.0) using an enzyme-linked immunosorbent assay, which had been standardized with antisera prepared against human collagen Type I in rabbits. Absorption studies were used to confirm the specificity of antibodies to human Type I collagen. Levels of antibody to Type I collagen detected in patients were higher (P less than 0.001) than in the control subjects.

This study was undertaken to assess the physical and biological properties of freeze-dried cross-linked bovine type I collagen and to assess its potential for use in the guided tissue regeneration method of treatment of periodontal disease in human adult subjects. The modulus of elasticity, swelling ratio, and biodegradation rate were investigated. The collagen sponge was implanted subdermally into Sprague-Dawley rats and a histological study carried out at 2, 7, 21, 35, and 49 days post implantation. Growth of human gingival and periodontal ligament derived fibroblasts on collagen sponge was assessed, as well as the effect of bovine collagen supernatants upon gingival and periodontal fibroblast cultures. The physical properties of the collagen sponge were consistent with good handling qualities and, therefore, it was appropriate for use at a surgical site. The histological study demonstrated a reduction in thickness of the collagen at 21 days; at 35 days there was a hazy appearance of the collagen remnants; and at 49 days the graft material had been completely replaced with fibrous tissues. The in vitro response of human gingival and periodontal fibroblasts to bovine collagen showed that, after 21 days, confluent fibroblast growth was observed around and underneath the sponge. The effect of bovine collagen supernatants upon fibroblasts demonstrated an apparent proliferative effect of the supernatant with both gingival and periodontal ligament fibroblasts. However, the non-parametric Friedman test revealed no significant differences between dilutions or time points. The overall findings provide encouraging evidence of the safety of freeze-dried cross-linked bovine collagen sponge in the surgical treatment of periodontal disease.(ABSTRACT TRUNCATED AT 250 WORDS)