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

The human immunoglobulin G (IgG) immune response against Porphyromonas (Bacteroides) gingivalis A7A1-28 iron-repressible membrane proteins (IRMPs) and other membrane proteins was examined by immunoblot analysis. Thirty sera from patients with adult periodontitis and 30 sera from periodontally healthy subjects were included. Iron limitation of P. gingivalis was achieved by growing bacteria in brain heart infusion broth supplemented with protoporphyrin IX and 250 microM alpha, alpha'-dypyridyl, a ferrous iron chelator. Iron-sufficient growth was achieved by growing bacteria in the same medium without alpha, alpha'-dypyridyl. Human sera, in particular those from patients with periodontitis who exhibited high levels of IgG against whole cells of P. gingivalis A7A1-28 in serum in an enzyme-linked immunosorbent assay (ELISA), commonly reacted with five membrane proteins with apparent molecular masses of 80, 67.5, 51, 40.5, and 28 kDa and four IRMPs of 46, 43, 37.5, and 22 kDa. More than 80% of the sera from patients with periodontitis and high levels of IgG against strain A7A1-28 in serum by ELISA reacted with the 46-, 43-, and 37.5-kDa IRMPs, and 40% of these subjects expressed immunoreactivity against the 22-kDa IRMP. Sera from patients with periodontitis and low levels of IgG against strain A7A1-28 in serum by ELISA and sera from periodontally healthy subjects exhibited less immunoreactivity against IRMPs and the five membrane proteins of P. gingivalis. The present study indicates that P. gingivalis IRMPs are immunogenic and that these proteins are expressed in vivo.
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PMID:Human immunoglobulin G antibody response to iron-repressible and other membrane proteins of Porphyromonas (Bacteroides) gingivalis. 205 Apr 7

Collagenases are known to be associated with tissue destruction in chronic inflammatory diseases such as periodontal diseases and rheumatoid arthritis. Collagenases are secreted by circulating inflammatory cells (polymorphonuclear leukocytes and monocytes), resident mesenchymal cells and epithelial cells in latent forms, which can be activated by proteases and compounds reacting with protein thiol groups. We have studied here the effects of oxygen-derived free radicals (ODFR) on latent human neutrophil collagenase. Also, in order to elucidate the cellular sources of collagenases, the ability of human gingival crevicular fluid (GCF) collagenases both from adult periodontitis (AP) and localized juvenile periodontitis (LJP) patients to degrade soluble interstitial collagen types I and II was studied. ODFR generated by the xanthine oxidase/hypoxanthine system in the presence of trace amounts of iron and EDTA activated latent neutrophil collagenase to an equal extent as the known activators phenylmercuric chloride and gold thioglucose. ODFR activation was inhibited by desferoxamine and mannitol as well as by superoxide dismutase and catalase. Clear differences in the susceptibility of collagen types I and II to AP and LJP GCF collagenases were observed. AP GCF collagenase degraded type I and II collagens at equal rates, resembling the substrate-specificity of human neutrophil collagenase. LJP GCF collagenase degraded type I collagen considerably faster than type II collagen, which was only negligibly degraded. This corresponds to the substrate specificity of fibroblast collagenase. Zymographic evaluation of gelatinolytic proteases showed the presence of 90 and 68 kD gelatinases in both AP and LJP GCF. Non-proteolytic means apparently provide a potent activation pathway of neutrophil collagenase in vivo and the hydroxyl radical was identified to be one of the potent activating oxidants.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Non-proteolytic activation of latent human neutrophil collagenase and its role in matrix destruction in periodontal diseases. 256 61

This article presents a brief review of literature on the role of iron in infection and reports the concentration of iron in crevicular fluid (CF) in humans and beagle dogs. Crevicular fluid from human subjects was collected from gingivitis and periodontitis sites. The CF from beagle dogs was collected from gingivitis and active periodontitis (ligature-induced) sites. The results showed that the concentration of iron in human CF was often higher than in human serum. Also, a comparison between CF collected from gingivitis sites and periodontitis sites revealed a significantly higher concentration of iron in CF collected from the periodontitis sites. The studies in ligature-induced periodontitis in beagle dogs revealed at least a 3-fold increase in iron concentration in CF following ligation compared to the preligation values. Based on the available literature it is suggested that high concentration of iron in CF is not due to serum transferrin or polymorphonuclear leukocyte lactoferrin. Also, this high concentration of iron in CF might play an important role in enhancement of growth and virulence of microorganisms of the subgingival plaque and the initiation of active periodontitis.
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PMID:The role of crevicular fluid iron in periodontal disease. 390 36

The purpose of this paper is to highlight briefly the major achievements and the remaining critical issues in the areas of epidemiology, microbiology, pathogenesis, diagnosis, and therapy. Periodontitis affects a relatively small proportion of study populations in the United States and other countries. Prevalence may be decreasing, but that remains to be seen. The identity and characteristics of susceptible individuals and groups are not known, and risk indicators for severe disease are only beginning to be identified. A very large number of different microbial species has been implicated in the etiology. It seems unlikely that all of these are essential participants. Essential participants need to be identified and better characterized. Whether putative pathogens are members of the commensal flora or exogenous species that must be transmitted is unclear. The relationship between the presence of a pathogenic flora and disease status is obscure. Pathogenic bacterial species are essential, but insufficient to cause disease. A susceptible host and local environmental factors--for example, elevated iron concentration--may be necessary for disease to occur. Many clonal types may not be virulent, and numbers greater than certain threshold levels appear to be necessary. The pathways by which bone and connective tissues of the periodontium are destroyed are sufficiently understood to permit development of therapies aimed at their modification. Examples are the use of vaccines, topical application of anti-inflammatory drugs, and use of chemically modified tetracyclines.
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PMID:Critical issues in periodontal research. 778 44

The oral spirochete, Treponema denticola is a putative etiologic agent in adult periodontitis, and acute necrotizing ulcerative gingivitis. In vitro, the oral treponeme produces several factors including proteases, hemolysins, hemin-binding proteins, which could potentially be involved in the virulence of this spirochete. Our laboratory has been investigating the pathobiology of T. denticola, and has demonstrated the production of several hemolysins by T. denticola. In this report two hemolysin genes from T. denticola strains ATCC 35404 (TD-4) and GM-1 were isolated by screening genomic DNA libraries of T. denticola on sheep blood agar plates. Physical maps of the insert fragments were not identical. Southern blot analyses suggested some degree of homology in the nucleotide sequence. Maxicell analyses of [35S]-methionine-labeled polypeptides from the recombinant plasmids have suggested the synthesis of an approximately 62.5 kDa polypeptide. Biochemical characterization of the T. denticola hemolysin genes indicated the activity to be inhibited by Mg2+, Ca2+ and Zn2+ but not by EDTA. Dithiothreitol and glutathione moderately enhanced the hemolytic activity of the recombinant plasmids. Iron partially inhibited the hemolytic activities. Addition of 2-2' bipyridyl moderately enhanced the activities, possibly by iron limitation. These results suggest the isolation of an identical hemolysin gene from T. denticola strains TD-4 and GM-1.
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PMID:Cloning and expression of hemolysin genes from Treponema denticola strains ATCC 35404 (TD-4) and human clinical isolate GM-1 in Escherichia coli. 781 17

The levels of 21 chemical elements (N, Na, Mg, P, Cl, K, Ca, Sr, Cr, Mn, Fe, Co, Zn, Se, Br, Rb, Sc, Ag, Sb, Hg) were measured in mixed unstimulated saliva of 50 patients with periodontal diseases (29 women and 21 men) aged 20 to 49 without concomitant diseases, five of these with gingivitis and the rest with generalized periodontitis of medium severity (27 cases) and grave (n = 18). A control group consisted of 52 healthy subjects with intact periodontium and teeth. A complex of instrumental methods has been developed and used in this study including neutron activation analysis (NAA) in two modifications and roentgen-fluorescent analysis. Changes in salivary levels of chemical elements were detected in the patients, these changes augmenting with severity of periodontal tissue involvement. In grave condition the concentrations of the major electrolytes were increased by 2.3 to 6.6 times on an average, of nitrogen twofold, of scandium, manganese, and chromium by 6.8-8.8 times, and of iron, cobalt, copper, selenium, bromine, silver, and mercury by 1.6-1.9 times; zinc level in mixed salivary protein reduced as the disease augmented in severity and in a grave form was only 62% of its normal content (p < 0.01). Salivary oversaturation with ions including Ca2+ which are conductive to salivary glycoprotein sedimentation and eventually to formation of a nutrient medium for pathogenic bacteria and zinc deficit indirectly indicating a reduced level of immunity status of the body are additional factors responsible for increased rate of dental deposit formation in periodontal diseases.
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PMID:[The chemical element content of mixed unstimulated saliva in periodontal diseases]. 819 35

The aim of the present study was to investigate whether incipient periodontal disease breakdown could be associated with changes in gingival crevicular fluid (GCF) acute-phase protein levels. In addition, the potential of clinical indices to act as predictors of significant attachment level (AL) change was investigated. AL measurements were taken at baseline and 3 months using the Florida Probe stent handpiece from a total of 384 sites in 38 patients. The average standard deviation of duplicate AL measurements was 0.423. When the tolerance method was used to detect significant AL change, 3.9% of the sites lost attachment. When a less stringent criterion of AL change of > or = 1 mm was used 9.9% of the sites lost attachment during the 3-month period. With the exception of probing depth, baseline clinical parameters failed to predict AL change. Fourteen active periodontitis sites that demonstrated significant attachment loss were paired to stable periodontitis sites within the same patient. The levels of four acute-phase proteins, namely alpha 2-macroglobulin (alpha 2-M), alpha 1-antitrypsin (alpha 1-AT), transferrin (TF) and lactoferrin (LF), and also albumin (Alb) were assessed in the same gingival crevicular fluid sample using sandwich ELISAs. Results were expressed either as ng/30 s and ng/microgram Alb. Acute-phase protein levels in GCF failed to differentiate between active and stable periodontitis sites at baseline. In conclusion, the degree of gingival inflammation of the tissues adjacent to the crevice/pocket seems to influence the levels of protease inhibitors and iron-binding proteins in GCF to a greater extent than probing attachment loss.
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PMID:Detection of stable and active periodontitis sites by clinical assessment and gingival crevicular acute-phase protein levels. 870 41

An hemR (hemin-regulated) gene from Porphyromonas gingivalis ATCC 53977 has been isolated and characterized. This gene is present downstream from the prtT gene, previously cloned in this laboratory. In addition, another putative gene, ORF1, was identified between hemR and prtT. The complete nucleotide sequences of ORF1 and hemR were determined, and the deduced amino acid sequence of ORF1 and HemR proteins corresponded to 16- and 48-kDa proteins, respectively. The amino termini of the HemR protein exhibited significant homology with iron-regulated, TonB-dependent outer membrane receptor proteins from various bacteria, while the carboxyl terminus of the HemR protein displayed almost complete identity with a P. gingivalis PrtT protease domain. PCR analyses confirmed the existence of such extensive homology between the carboxyl termini of both the prtT and hemR genes on the P. gingivalis chromosome. Northern blots indicated that ORF1 was part of a 1.0-kb mRNA and was positively regulated by hemin levels. On the other hand, the hemR gene was apparently a part of a 3.0-kb polycistronic message and was negatively regulated at the transcriptional level by hemin. Primer extension analysis of the hemR gene revealed that the transcription start site was at a C residue located within ORF1. An examination of HemR::lacZ constructs in both Escherichia coli and P. gingivalis confirmed hemin repression of hemR expression in both organisms. Moreover, the HemR protein expressed in E. coli was detected by an antiserum from a periodontitis patient heavily colonized with P. gingivalis but not by serum from a periodontally healthy patient or by antisera against hemin-grown P. gingivalis cells. Therefore, it is likely that the 48-kDa HemR protein can be expressed only under hemin-restricted conditions. These results suggest that we have isolated a hemin-regulated gene, hemR, which encodes a 48-kDa protein that may be a TonB-dependent outer membrane protein.
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PMID:Isolation and characterization of a hemin-regulated gene, hemR, from Porphyromonas gingivalis. 906 34

A 40-kDa lactoferrin-binding protein was identified in a strain of Prevotella nigrescens isolated from a patient with periodontitis. The protein was purified by affinity column chromatography using a Sepharose-lactoferrin column and detergent-solubilized membranes. The N-terminal sequence revealed no apparent similarities with any other sequenced bacterial protein. The native conformation of the 40-kDa protein was a condition to bind either iron-free or iron-saturated lactoferrin. A possible function of this Lf-binding protein could be related with an iron acquisition mechanism in P. nigrescens.
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PMID:Identification of a lactoferrin-binding protein in Prevotella nigrescens. 916 7

Prevotella intermedia, a putative periodontopathic microorganism, requires iron for growth. Hemoglobin can be a major source of iron for bacterial growth in vivo since it is present in the crevicular fluid collected from periodontitis sites. Experiments studying the growth of P. intermedia in iron-depleted Todd-Hewitt broth supplemented with human hemoglobin showed that the bacteria were able to utilize human hemoglobin as a source of iron. The uptake of iron from hemoglobin by P. intermedia appears to be initiated by the binding of hemoglobin to the bacteria as shown by direct binding studies using 125I-labeled human hemoglobin. Scatchard analysis of saturation binding data revealed that 125I-labeled human hemoglobin had a dissociation constant (Kd) of 2.53 x 10(-8) M for the receptor on P. intermedia. Binding of labeled hemoglobin to P. intermedia was competitively inhibited by unlabeled human hemoglobin showing that the binding was specific. The ability of bovine hemoglobin, but not hemin or non-hemoglobin heme-containing compounds, to inhibit binding competitively suggested that the globin moiety of the hemoglobin molecule is recognized by the hemoglobin binding receptors.
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PMID:The binding and utilization of hemoglobin by Prevotella intermedia. 962 57


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