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Query: UMLS:C0031099 (periodontitis)
 12,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Many pathogenic bacteria possess cell surface receptors which can bind immunoglobulins via the Fc portion. The aim of this study was to characterize the human immunoglobulin G (IgG) Fc-binding activity of Prevotella intermedia, a suspected etiologic agent of adult chronic periodontitis. The Fc-binding activity of P. intermedia on whole cells and on extracellular vesicles was demonstrated. Incubation of P. intermedia cells in the presence of Zwittergent 3-14 allowed complete solubilization of the Fc receptor from the cell surface. This cell envelope extract was thus used to characterize the Fc-binding activity. A microtiter plate assay using alkaline phosphatase-labeled Fc fragments showed that preincubation of the cell envelope extract with human IgG, human IgG Fc fragments, or human serum completely inhibited the Fc-binding activity. Partial inhibition was obtained with human IgG F(ab')2 fragments, whereas no inhibition occurred following preincubation with human IgA, carbohydrates, and selected proteins. Preincubation of the cell envelope extract with IgG from a variety of animals demonstrated that rabbit, mouse, rat, goat, and sheep IgG did not inhibit Fc-binding activity, whereas cow, pig, and dog IgG partially inhibited Fc-binding activity. A strong inhibition comparable to that obtained with human IgG was noted with monkey IgG. The Fc receptor of P. intermedia is thus different from the six types previously reported in other nonoral bacteria. Polyacrylamide gel electrophoresis and Western blotting (immunoblotting) analysis of the cell envelope extract revealed a major band with a molecular mass of approximately 65 kDa which reacted with peroxidase-labeled human IgG Fe fragments. Transmission electron microscopy showed a uniform distribution of the Fc receptor on the bacterial surface, as revealed by gold labeling. The Fc-binding activity demonstrated in this study may act as an additional virulence factor for P. intermedia by reducing IgG reactions with the bacterial cell.
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PMID:Characterization of the human immunoglobulin G Fc-binding activity in Prevotella intermedia. 779 Jan 1

Eight adult periodontitis (AP) patients were studied immunohistochemically to determine the presence of matrix metalloproteinases (MMPs) MMP-1, MMP-3, and MMP-8 in the marginal gingival and gingival granulation tissue specimens obtained from periodontal flap surgery after scaling and root planing. Clinically healthy gingival tissue specimens obtained from impacted third-molar extraction operations served as controls. MMP-type-specific antisera were applied by the avidin-biotin-peroxidase complex staining method. Moderate immunoreactivity for neutrophil collagenase (MMP-8) was found both in the AP patients' marginal gingival connective tissue and in gingival granulation tissue specimens. Immunoreactivity for fibroblast-type collagenase (MMP-1) and stromelysin-1 (MMP-3) was detected only in the AP patients' gingival granulation tissue specimens. In the control specimens, no immunoreactivity for the MMPs could be detected. For the first time, this finding demonstrates immunohistochemically the presence of MMP-8 in human inflamed gingiva in situ, and further highlights the importance of MMP-8 in periodontal tissue destruction, evidently during the acute phase(s) of the disease. However, our results confirm and extend previous studies indicating that other types of MMPs from resident gingival cell sources also seem to participate in the chronic and destructive course of periodontal inflammation.
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PMID:Immunohistochemical study of neutrophil- and fibroblast-type collagenases and stromelysin-1 in adult periodontitis. 787 57

The cells of a human oral spirochete, Treponema denticola ATCC 35405, and of seven clinical isolates of this organism obtained from the subgingival dental plaque of periodontitis patients were studied for their ability to grow in an aerobic and an anaerobic environment, and for their profile of peptidohydrolase and oxidoreductase enzymes. The growth yield of aerobically grown cultures was either comparable to or higher than that of anaerobically grown ones regardless of whether prereduced broth, freshly prepared broth or oxidized broth was used. However, elimination of certain supplements from the growth media resulted in poor growth regardless of the nature of the gaseous environment. The microscopic morphology and motility of the cells were not affected by differences in the gaseous atmosphere. Quantitative studies on several peptidohydrolase activities suggest that anaerobically grown cells displayed higher specific activity especially toward N alpha-L-prolyl-2-naphthylamine, indicating that increased synthesis of proline iminopeptidase enzymes (or enzyme) of the cells was associated with anaerobic growth conditions. The formation of enzymes hydrolysing N alpha-benzoyl-DL-arginyl-2-naphthylamine (and the corresponding p-nitroaniline) was not affected to the same extent. Growth experiments suggest that T. denticola ATCC 35405 is a facultatively anaerobic spirochete instead of an obligate anaerobe as reported in previous literature. The quantitative enzyme studies suggest that the gaseous growth atmosphere of the cells can exert a selective effect on the activity levels of certain peptidolytic enzymes of this organism. Such effects were not observed when the whole cells were studied by means of qualitative or semi-quantitative enzyme tests. The activities of catalase, peroxidase and superoxide dismutase of the cells were low and variable. Because of this, it was not possible to relate these oxidoreductase activities to the composition of the gaseous atmosphere.
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PMID:Proteolytic and oxidoreductase activity of Treponema denticola ATCC 35405 grown in an aerobic and anaerobic gaseous environment. 824 25

The presence, localization and activities of cathepsin G in gingival tissue specimens and crevicular fluid (GCF) from 9 adult periodontitis patients and 6 controls with clinically healthy periodontium were studied by use of avidinbiotin-peroxidase complex method, Western and dot blotting, and spectrophotometric activity assay. In contrast to healthy gingival tissue specimens, gingival tissue specimens collected from adult periodontitis patients contained inflammatory cells in lamina propria, beneath the oral sulcular epithelium, 10-50% of which were cathepsin G positive polymorphonuclear neutrophilic leukocytes (PMNs) and monocyte/macrophage-like cells. Cathepsin G activities were increased in adult periodontitis GCF when compared to periodontally healthy controls' GCF (p < 0.05). In adult periodontitis GCF, Western blotting disclosed free cathepsin G but also clear complexes of cathepsin G with its predominant endogenous inhibitor alpha 1-antichymotrypsin (alpha 1-ACT). The present results demonstrate that part of the cathepsin G, despite the presence of increased concentrations of alpha 1-ACT, was in an uncomplexed, free and functionally active form. Our results suggest that GCF cathepsin G reflects the disease process in adjacent inflamed gingiva and also increased host response to microbiota and/or dental plaque in the periodontitis lesions. Cathepsin G may contribute to periodontal tissue destruction directly and indirectly, via proteolytic activation of latent neutrophil procollagenase (promatrix metalloproteinase-8 [proMMP-8]).
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PMID:Cathepsin G in gingival tissue and crevicular fluid in adult periodontitis. 884 41

Actinobacillus actinomycetemcomitans is a Gram-negative bacterium which has an important role in localized juvenile and in progressive periodontitis. It is sensitive to killing by the myeloperoxidase (MP)-hydrogen peroxide (H2O2)-chloride system which is part of the innate host defense mediated by polymorphonuclear leukocytes. Since it has been recently suggested that thiocyanate, instead of chloride, could serve as a main substrate for MP as for lactoperoxidase (LP) and salivary peroxidase, we investigated in this study the effect of both LP and MP systems on A. actinomycetemcomitans with different (pseudo)halide substrates, thiocyanate, chloride and iodide. The concentrations of the substrates were physiological for oral fluids, as was the concentration range of H2O2. Both peroxidases produced end products with identical antibacterial activity with thiocyanate and iodide. The oxidation of iodide resulted in the highest antimicrobial efficiency followed by chloride and thiocyanate. Addition of thiocyanate into either MP-H2O2-chloride or MP/LP-H2O2-iodide system abolished the bactericidal activity of the oxidized halide. However, the chloride did not affect the bactericidality of the MP-H2O2-iodide system, but when all 3 (pseudo)halide substrates were present no antimicrobial effect was recorded. Our study shows that the presence of thiocyanate in physiological amounts is able to prevent the bactericidal activity of halide-peroxidase systems in low H2O2 concentrations. These results explain why thiocyanate-peroxidase systems of either innate origin (saliva, crevicular fluid) or introduced by commercial oral hygiene products are most probably ineffective against A. actinomycetemcomitans in vivo. Further studies of halide/thiocyanate ratio are needed to develop products which are also effective against oral anaerobes.
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PMID:The effects of different (pseudo)halide substrates on peroxidase-mediated killing of Actinobacillus actinomycetemcomitans. 984 7

A method was developed to evaluate the presence of immunoglobulin G (IgG) subclass (1-4) antibody to Actinobacillus actinomycetemcomitans, serotype b (strain Y4) in patients with early-onset periodontitis on a single nitrocellulose membrane. Sera from 30 early-onset periodontitis patients and gingival crevicular fluid samples from 2 patients were collected and tested with four different preparations of A. actinomycetemcomitans (Y4). The principle steps of the assay are: a) binding of the bacterial antigen (Y4) and the anti-human IgG antibody (capture antibody) in parallel lanes on nitrocellulose membranes; b) incubation of known concentrations of the IgG subclasses 1, 2, 3 and 4, as well as a dilution of serum and/or gingival crevicular fluid from patients in lanes perpendicular to the antigen lanes; c) incubation of the membranes with the corresponding peroxidase conjugated anti-human IgG subclass secondary antibody; d) detection of positive signals by enhanced chemiluminescence. The blots were evaluated by visual comparison to a series of blots containing known concentrations of IgG subclasses. The method was used to rapidly screen a relatively large number of patient sera and gingival crevicular fluid samples for IgG subclasses in a cost-effective assay. The predominant IgG subclass found in early-onset periodontitis was IgG2.
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PMID:Rapid evaluation of serum and gingival crevicular fluid immunoglobulin G subclass antibody levels in patients with early-onset periodontitis using checkerboard immunoblotting. 1009 31

Children with insulin-dependent diabetes mellitus have a lower salivary flow rate, pH and buffer capacity, but a higher glucose content and peroxidase, IgA, magnesium and calcium concentration, in comparison with healthy children. Nevertheless the incidence of caries is lower than normal in diabetic children with good metabolic control. Periodontal disease usually starts at puberty as mild gingivitis with bleeding and gingival recession, and it may develop into severe periodontitis, especially in children with poor control of diabetes. Microangiopathy, impaired immune response, different bacterial microflora and collagen metabolism are involved in the pathogenesis of diabetic periodontal disease. The gingival flora is mostly composed of Gram-negative, anaerobic bacteria, while collagen has a lower solubility and is atrophic and inadequate to support the occlusion forces. For these reasons, prevention of periodontitis is important in diabetic children; they should receive oral hygiene instruction and visit a dentist at least twice a year.
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PMID:Oral health in children and adolescents with IDDM--a review. 1070 31

Previous investigations have shown that subjects with rapidly progressive periodontitis (RPP), an early-onset aggressive form of periodontitis, have polymorphonuclear leukocytes (PMNs) with increased intracellular levels of beta-glucuronidase, a characteristic enzyme of azurophil lysosomes. The current study attempted to account for that increase. Ten healthy controls and 10 otherwise healthy subjects with RPP participated. PMNs from peripheral blood were separated, fixed and reacted for peroxidase to identify azurophil lysosomes. Using transmission electron microscopy, 20 PMNs per subject were photographed at 10,000x. Photographs were subsequently digitized and analyzed by computer. RPP PMNs had a higher percentage of the area of the cell profile occupied by azurophil lysosomes compared to control subjects' PMNs. The RPP subjects also had greater absolute numbers of azurophil lysosomes per cell. Lysosome shape was assessed visually. There were no differences between RPP and control groups for lysosome shape, with the majority of lysosomes in each group exhibiting a round or oval shape. RPP lysosomes did exhibit a significantly greater mean size.
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PMID:Morphology of azurophil lysosomes in polymorphonuclear leukocytes from humans with rapidly progressive periodontitis. 1079 6

Children with insulin-dependent diabetes mellitus have a lower salivary flow rate, pH and buffer capacity, but a higher glucose content and peroxidase, IgA, magnesium and calcium concentration, in comparison with healthy children. Nevertheless the incidence of caries is lower than normal in diabetic children with good metabolic control. Periodontal disease usually starts at puberty as mild gingivitis with bleeding and gingival recession, and it may develop into severe periodontitis, especially in children with poor control of diabetes. Microangiopathy, impaired immune response, different bacterial microflora and collagen metabolism are involved in the pathogenesis of diabetic periodontal disease. The gingival flora is mostly composed of Gram-negative, anaerobic bacteria, while collagen has a lower solubility and is atrophic and inadequate to support the occlusion forces. For these reasons, prevention of periodontitis is important in diabetic children; they should receive oral hygiene instruction and visit a dentist at least twice a year.
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PMID:Oral health in children and adolescents with IDDM--a review. 1085 89

Sixty-five patients with generalised early-onset periodontitis (G-EOP) (age range 16-42 years, 32 smokers and 33 non-smokers) were assessed for antibody titres and avidity to a panel of five suspected periodontal pathogens (Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Prevotella intermedia, Treponema denticola and Bacteroides forsythus). Thirty-four of these patients were untreated (17 smokers and 17 non-smokers), and thirty-one were in the maintenance phase of periodontal therapy (15 smokers and 16 non-smokers). Previous studies have investigated the effect of smoking on IgG levels in periodontitis patients in the context of the more extensive periodontal destruction seen in smokers. Based on this literature our hypothesis was that smokers would have depressed serum IgG levels directed against recognised periodontal pathogens compared with non-smokers. Antibody titres were measured by ELISA deploying fixed whole cells as coating. The IgG response was detected with biotin-anti-human IgG and avidin-peroxidase; avidity was determined by elution with ammonium thiocyanate. Median titres to A. actinomycetemcomitans, P. intermedia and T. denticola were significantly lower in maintenance patient smokers (p= 0.02, 0.02 and 0.002 respectively) but not in untreated patients. Avidity to P. gingivalis was also lower in smoking maintenance patients (p = 0.003) but not in untreated patients. These findings may imply some interruption of immune maturation in smokers following periodontal treatment.
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PMID:Humoral immune response in early-onset periodontitis: influence of smoking. 1151 95


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