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PubMed1999

Bacteremia after dental treatment in mentally handicapped people.

Bacteremia may occur after disruption of the oral mucous membrane, particularly after dental treatment. 18 mentally handicapped patients who underwent dental treatment with general anesthesia were included in our study. None of the patients had general illnesses or received antibiotic protection. From each patient several blood samples were drawn aseptically during dental treatment and cultured. The majority of aerobic bacteria recovered belonged to Streptococcus sp and Gemella sp., anaerobic bacteria mainly belonged to Porphyromonas gingivalis and Peptostreptococcus sp. Resistance of the isolated bacteria to penicillin as well as to oxacillin, erythromycin and Co-trimoxazole was substantial. The highest resistance rate could be shown against fucidic acid.

Adolescent↗
PubMed2001

Soluble antagonists to interleukin-1 (IL-1) and tumor necrosis factor (TNF) inhibits loss of tissue attachment in experimental periodontitis.

BACKGROUND, AIMS: Periodontal disease is a significant cause of tooth loss among adults and is characterized by the alteration and permanent destruction of the deeper periodontal tissues. Although the presence of pathologic microbes is required to trigger this process, the amplification and progression of the diseased state is believed to rely heavily on the production of host mediators in response to bacteria or their metabolic products. The inflammatory response is effective in preventing large-scale colonization of the gingival tissues by bacteria that lie in close proximity to the tooth surface or within the gingival sulcus. It has been postulated that the host-response in some individuals may lead to an over-reaction to invading oral pathogens resulting in the destruction of periodontal tissues. METHODS: Several host-derived mediators are believed to contribute to this response. Two agents considered to be essential in periodontal destruction are interleukin-1 (IL-1) and tumor necrosis factor (TNF). We investigated the role of IL-1 and TNF in the loss of connective tissue attachment in a Macaca fascicularis primate model of experimental periodontitis. Silk ligatures impregnated with the periodontal pathogen, Porphyromonas gingivalis were wrapped around the posterior teeth and the activity of IL-1 and TNF were inhibited by soluble receptors to these proinflammatory cytokines via local injection into interdental papillae. RESULTS: Histomorphometric analysis indicates that IL-1 and TNF antagonists significantly reduced the loss of connective tissue attachment by approximately 51% and the loss of alveolar bone height by almost 91%, both of which were statistically significant. CONCLUSION: This investigation demonstrates that the loss of connective tissue attachment and progression of periodontal disease can be retarded by antagonists to specific host mediators such as IL-1 and TNF and may provide a potential treatment modality to combat the disease process.

Alveolar Bone Loss↗
PubMed2003

Guided tissue regeneration using a polylactic acid barrier.

OBJECTIVES: The purpose of this study was to determine the relative impact of various predictors responsible for the variability in treatment outcome after guided tissue regeneration (GTR) in intraosseous periodontal defects. PATIENTS AND METHODS: 30 patients with chronic periodontitis and at least one intraosseous periodontal lesion (> or =4 mm) were enrolled. Following full-mouth scaling, GTR using polylactic acid membranes was performed at one site in each patient. Main periodontal pathogens, defect morphology, membrane exposure and smoking habit were assessed as predictor variables. Alveolar bone level change served as the primary outcome variable in a multiple regression analysis. RESULTS: After 12 months, the 29 patients completing the study showed alveolar bone changes ranging from 4 mm bone gain to 1 mm bone loss (mean: 1.6+/-0.4 mm gain). Active smoking (beta-weight:-0.49, P=0.003) and persistence of subgingival infection with P. gingivalis (P.g.) (beta-weight:-0.25, P=0.11) were associated with poor treatment outcome. Deep initial intraosseous defects (beta-weight: 0.32, P=0.045) were associated with favorable treatment outcome, and membrane exposure had no impact on bone gain. CONCLUSION: Active smoking was the strongest predictor variable negatively affecting alveolar bone gain following GTR in the treatment of periodontal defects. It was followed by a positive influence of a deeper intraosseous defect and by a negative effect by persistent subgingival infection of P. gingivalis. The relative impact of these factors may be useful in assessing the prognosis of GTR in intraosseous periodontal defects.

Adolescent↗
PubMed2003

A rapid DNA probe test compared to culture methods for identification of subgingival plaque bacteria.

There has been a significant amount of interest in developing a more rapid and cost-effective test to identify bacterial pathogens in plaque. DNA probe technology may meet both these objectives, it is more rapid and cost-effective when compared to culture methods. The purpose of this study was to compare an automated DNA probe test with classical culture methods for identifying Bacteroides forsythus and Porphyromonas gingivalis in subgingival plaque of patients with adult periodontitis. Subgingival plaque samples were collected from sites with moderate to severe periodontitis and divided into two aliquots for analysis by either DNA probe or culture methods. When the DNA probe method was compared with the culture method (gold standard), the sensitivity and specificity for B. forsythus were 92.0% (SE = 3.4%) and 50.5% (SE = 7.8%), respectively; for P. gingivalis they were 52.2% (SE = 8.7%) and 74.7% (SE = 5.9%), respectively. Detection of B. forsythus and P. gingivalis by DNA probe correlated with probing depth (P = 0.01 for B. forsythus and P = 0.03 for P. gingivalis). It was concluded the DNA probe test was comparable to culture methods in detecting B. forsythus. In addition, when compared to the culture method, a better correlation was obtained with DNA probe detection of B. forsythus or P. gingivalis and clinical parameters.

Adult↗
PubMed2000

Relevance of IgG receptor IIIb (CD16) polymorphism to handling of Porphyromonas gingivalis: implications for the pathogenesis of adult periodontitis.

Polymorphonuclear neutrophils (PMNs) are essential in host defense against periodontopathic bacteria such as Porphyromonas gingivalis. The uptake of immunoglobulin G (IgG)-opsonized bacteria via IgG Fc receptors (Fc gamma R) on PMN constitutes a central defense mechanism in periodontium. Fc gamma RIIIb is the most abundantly expressed Fc gamma R on PMN and is functionally polymorphic. The Fc gamma RIIIb-NA1 and IIIb-NA2 allotypes interact differently with IgG1- and IgG3-opsonized particles. We recently showed recurrence rates of adult periodontitis (AP) to be higher in patients carrying at least 1 Fc gamma RIIIb-NA2 allele. In this study we evaluated the functional relevance of the Fc gamma RIIIb polymorphism to anti-P. gingivalis PMN effector functions. Our results showed Fc gamma RIIIb-NA2-carrying PMN from both patients with AP and healthy controls to be less efficient in phagocytosis and induction of oxidative burst upon interaction with IgG1- and IgG3-opsonized P. gingivalis. These functional differences between Fc gamma RIIIb-NA1 and IIIb-NA2 were observed in the presence of CD32-blocking antibody fragments, but not upon blocking CD16. Moreover, PMNs from AP patients exhibited increased Fc gamma RIIIb-allelic differences in IgG3-induced oxidative burst compared to control PMNs. These results support the concept that Fc gamma RIIIb heterogeneity may influence the clinical course of AP.

Adult↗
PubMed2000

The Prevotella intermedia group organisms in young children and their mothers as related to maternal periodontal status.

Currently, the Prevotella intermedia group includes three biochemically and phylogenetically related species: Prevotella intermedia, Prevotella nigrescens, and the newly described Prevotella pallens. The two first-named species are mentioned with varying emphasis in connection with periodontal diseases, while such a connection of P. pallens is not known. Mothers serve as a plausible source of bacteria to their children, and conceivably, a mother with periodontitis as a recurrent reservoir of periodontally infecting organisms. In the present study, 23 mothers and their young children were examined for the presence of the P. intermedia group organisms in relation to maternal periodontal status (I: periodontal health, II: initial periodontitis, and III: advanced periodontitis). Species differentiation was based on established biochemical methods, electrophoretic mobility patterns, SDS-PAGE, and DNA hybridization. P. intermedia was not recovered from children but nearly exclusively from mothers in group III, thus confirming its association with periodontitis. P. nigrescens and P. pallens were frequently found in mothers and children. To determine bacterial transmission between a mother and her child, 72 isolates from 13 mother-child pairs were analyzed by arbitrarily primed PCR (AP-PCR). Similar AP-PCR types of P. nigrescens and/or P. pallens were recovered from 3/4 pairs in group I, 2/5 pairs in group II, and none in group III. Our results indicate that different species within the P. intermedia group have a different colonization pattern in childhood and that the periodontal status reflects qualitatively their presence in maternal saliva. Intra-familial transmission of P. nigrescens and P. pallens can occur in early childhood, however similar AP-PCR types were most obvious within periodontally healthy mother-child pairs.

Adult↗
PubMed2002

Recognition of the carbohydrate modifications to the RgpA protease of Porphyromonas gingivalis by periodontal patient serum IgG.

Periodontal infections by Porphyromonas gingivalis are associated with a sustained systemic IgG antibody response and elevations in local antibody synthesis to this organism. One of the targets of this response is a protease, RgpAcat, which is an important virulence determinant of this organism. Recently, we demonstrated that this molecule is glycosylated and that the glycan chains are immunologically related to P. gingivalis lipopolysaccharide (LPS) (Curtis et al., Infect Immun 1999;62:3816-3823). In the present study, we examined the role of these glycan additions in the immune recognition of RgpAcat, by sera from adult periodontal patients (n = 25). Serum IgG antibody levels to P. gingivalis W50, RgpAcat and LPS and to recombinant RgpA were determined by enzyme-linked immunosorbant assay (ELISA). No correlation was observed between the antibody levels to RgpAcat from P. gingivalis and the recombinant form of this enzyme expressed in Escherichia coli. However, a strong association was found between the recognition of LPS and the wild-type enzyme (R = 0.8926; p = 0.0005). Incorporation of LPS into the ELISA led to a significant reduction (mean 25%; range 0.8-43%, SD = 15; p < 0.05) in the recognition of RgpAcat, but had no effect on the recognition of control antigens. Deglycosylation of RgpAcat led to the abolition of immune recognition by patient serum IgG, which suggests that the glycan additions to this molecule are the principal targets of the immune response. Therefore, glycosylation of the RgpAcat protease may play an important role in immune evasion by shielding the primary structure from immune recognition.

Adhesins, Bacterial↗
PubMed2002

Three case reports of aggressive periodontitis associated with Porphyromonas gingivalis in younger patients.

The terms 'early onset periodontitis' (EOP) and 'juvenile periodontitis' (JP) were replaced by that of 'aggressive periodontitis' in a recent international workshop for the classification of periodontal diseases and conditions. The chief etiologic agent for aggressive periodontitis is considered to be Actinobacillus actinomycetemcomitans in localized juvenile periodontitis. Porphyromonas gingivalis is also mentioned as the etiologic agent of the aggressive periodontitis, although to date its role remains questionable. This communication describes three cases of aggressive periodontitis found to be associated with P. gingivalis but not A. actinomycetemcomitans by polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA). Our findings clarify the role of P. gingivalis as an etiologic agent in this type of periodontitis and confirm its inclusion in the current definition of aggressive periodontitis.

Adolescent↗
PubMed2003

The herpesvirus-Porphyromonas gingivalis-periodontitis axis.

OBJECTIVES AND BACKGROUND: Members of the herpesvirus family have accumulated considerable support for a role in severe types of periodontitis. This study aimed to examine whether human cytomegalovirus (HCMV), Epstein-Barr virus type 1 (EBV-1) or herpes simplex virus (HSV) together with the major periodontopathic bacterium Porphyromonas gingivalis might interact in the pathogenesis of periodontal breakdown. METHODS: Sixteen subjects each contributed paper point samples from two progressing and two stable periodontitis lesions, as determined by ongoing loss of probing attachment. Polymerase chain reaction methodology was used to identify subgingival herpesviruses, P. gingivalis and other bacterial pathogens. Chi-squared tests and multivariate logistic regression were employed to identify statistical associations between herpesviruses, periodontopathic bacteria and clinical variables. RESULTS: HCMV and HSV were both significant predictors of the presence of subgingival P. gingivalis. In turn, P. gingivalis was positively associated with periodontitis active disease, probing attachment level, probing pocket depth, gingival bleeding upon probing and patient age. EBV-1 was not linked to P. gingivalis, although the virus was predictive of periodontitis active disease. The periodontitis disease risk associated with herpesvirus-P. gingivalis combinations depended on both site-specific and subject-specific factors. CONCLUSION: The present data of aggressive periodontitis implicate HCMV, HSV and P. gingivalis as either cofactors in its etiology or triggers of relapses. Further studies are needed to determine the spectrum of periodontopathogenicity of herpesviruses and effective management of these viruses in periodontal sites.

Adult↗
PubMed2003

Immune responses to heat shock protein in Porphyromonas gingivalis-infected periodontitis and atherosclerosis patients.

BACKGROUND: It has been widely thought that heat shock protein might be involved in autoimmune disease mechanisms in humans. OBJECTIVES: The present study was performed to evaluate the recognition of Porphyromonas gingivalis heat shock protein 60 (hsp60) and human hsp60 by immune sera in P. gingivalis-infected periodontitis and atherosclerosis patients. MATERIALS AND METHODS: Mononuclear cells from atheroma lesions were stimulated with P. gingivalis hsp and sera from periodontitis or atherosclerosis patients were subjected to Western immunoblotting to P. gingivalis hsp or human hsp, respectively. RESULTS: Western immunoblot analysis demonstrated the dual reactivity of anti-P. gingivalis antisera with P. gingivalis hsp and human hsp. We could also establish P. gingivalis hsp-specific T cell lines from the atheroma lesions, a mixture of CD4+ and CD8+ cells producing the cytokines characteristic of both Th1 and Th2 subsets. CONCLUSION: These observations suggest the modulating effect of P. gingivalis hsp60 in the immunopathogenesis of periodontitis and atherosclerosis.

Adult↗
PubMed2003

The genetic relatedness of Porphyromonas gingivalis clinical and laboratory strains assessed by analysis of insertion sequence (IS) element distribution.

OBJECTIVES: Porphyromonas gingivalis is frequently found in periodontitis lesions. This organism contains a large number of insertion sequence (IS) elements. We sought to determine the distribution of seven IS elements from strain W83 among nine P. gingivalis laboratory strains and nine clinical isolates and to use these findings to determine strain relationships. METHODS: Southern blots of BamHI digested genomic DNA digests were probed with insertion sequence elements ISPg1-7. RESULTS: The restriction fragment length polymorphism (RFLP) patterns revealed that five of the nine laboratory strains, including strain W83, were nearly identical for all seven IS elements. Two of nine clinical isolates were similar to the five laboratory strains. Two of the four remaining laboratory strains had similar or identical RFLP patterns. The remaining two laboratory strains had limited similarity to clinical strains. Four of the clinical isolates had identical RFLP patterns for all seven IS elements. The three remaining clinical isolates were unique in their RFLP patterns. Several strains lacked from one to four of the IS elements. Similar strain relationships were suggested regardless of the IS element examined. CONCLUSIONS: Transposition and recombination between IS elements are not sufficiently pervasive to obscure strain relationships, though this does not preclude the possibility that such events play an important role in allowing P. gingivalis to adapt to new environments. Given the level of genetic diversity observed, it may be especially important to examine genetically diverse strains when drawing conclusions based on the W83 P. gingivalis genomic database.

Adaptation, Physiological↗
PubMed2003

Expression of endothelin-1 in gingival epithelial cells.

OBJECTIVES AND BACKGROUND: Endothelin-1 (ET-1) is a 21-amino acid peptide with multifunctional regulation. ET-1 expresses in various cells during inflammation. The present study aimed to examine the ET-1 expression in oral epithelial cells after infection with the periodontal pathogen and to investigate the presence of ET-1 in human inflamed and uninflamed gingival tissues. MATERIALS AND METHODS: The KB cells were infected with Porphyromonas gingivalis and the expression level of ET-1 was examined using reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). The immunohistochemical analysis of ET-1 was performed in gingival tissues obtained from patients. In addition, the ET-1 mRNA expression in each tissue was also investigated by RT-PCR. RESULTS: The expression of ET-1 in KB cells was strongly induced by the P. gingivalis infection. On the other hand, the strong immunoreactivity for ET-1 was observed in the epithelium and vascular endothelial cells of the inflamed gingival tissue. Furthermore, the level of ET-1 mRNA was greater in the inflamed tissues. CONCLUSION: These results suggested that the expression level of ET-1 in gingival epithelial cells might be enhanced during the periodontal inflammation.

Adult↗
PubMed2003

Antibody responses to Porphyromonas gingivalis infection in a murine abscess model--involvement of gingipains and responses to re-infection.

BACKGROUND: Porphyromonas gingivalis is one of the most important periodontopathogens. It produces cysteine proteinases named gingipains. We previously examined the effect of gingipains on abscess formation in a murine model. The rgpA rgpB double and kgp mutants induced smaller abscesses than the wild type. Moreover, the rgpA rgpB kgp triple (gingipain-null) mutant hardly showed lesion formation at all under the experimental conditions used, indicating that genes encoding gingipains are important for P. gingivalis virulence. OBJECTIVES: Here, we further report the humoral immune responses induced by P. gingivalis strains. METHODS: After the lesions were apparently cured, sera were collected from the mice and immunoglobulin G (IgG) responses against the whole cell antigens of wild-type P. gingivalis were measured. RESULTS: Wild-type strain was found to induce a strong antibody reaction. On the other hand, the rgpA rgpB kgp triple and kgp mutants induced significantly lower antibody responses compared to the wild type. Western blotting analysis confirmed the differences in antibody production. Next, these mice were re-infected with wild-type strain. Mice that were first infected with wild-type strain showed significantly smaller lesion formation than control mice that were first infected with medium only. On the other hand, mice that were first infected with mutant strains devoid of gingipain activities did not show resistance to re-infection and immunoglobulins directed against gingipains may be protective. CONCLUSIONS: These results suggest that gingipains play an important role in abscess formation in mice, and humoral immune responses seem to be partly responsible for the resistance to re-infection by P. gingivalis.

Abscess↗
PubMed2003

Antimicrobials for the treatment of aggressive periodontitis.

Aggressive periodontitis is characterized by a considerable attachment loss over a relatively short period of time. It may be the consequence of either the presence of highly aggressive pathogens or a highly susceptible host. In the first case, the use of antimicrobials should be beneficial in the treatment of those patients. However, due to the organization of the micro-organisms as a biofilm, the increasing incidence of allergies and resistance against antimicrobials and their side-effects, there is still controversy about their benefit in the treatment of periodontal disease. This paper discusses indications for the use of antimicrobials, the substances prescribed and the type of application under the conditions of aggressive periodontitis.

Actinobacillus Infections↗
PubMed2003

Sustained exposure to bacterial antigen induces interferon-gamma-dependent T cell receptor zeta down-regulation and impaired T cell function.

T cell antigen receptor zeta chain down-regulation and impaired in vitro T cell function have been described in cancer and autoimmune and infectious diseases. However, the immunological basis for this phenomenon is unknown. Sustained exposure to antigen and chronic systemic inflammation, factors shared by the various pathologies, might account for this phenomenon. We developed an in vivo experimental system that mimics these conditions and show that sustained exposure of mice to bacterial antigens was sufficient to induce T cell antigen receptor zeta chain down-regulation and impair T cell function, provided an interferon-gamma-dependent T helper type 1 immune response developed. This indicates zeta chain down-regulation could be a physiological response that attenuates an exacerbated immune response. However, it can act as a 'double-edged sword', impairing immune responses to chronic diseases.

Animals↗
PubMed1986

The purification and some equilibrium properties of the nitrite reductase of the bacterium Wolinella succinogenes.

The bacterium Wolinella succinogenes produces a nitrite reductase enzyme that can be purified to homogeneity in high yield by a combination of detergent extraction, hydroxyapatite chromatography and Mr fractionation. Nitrite reductase activity is found to be present in both a high- and a low-Mr fraction. The high-Mr fraction has been shown to consist of the low-Mr nitrite reductase enzyme associated with a hydrophobic 'binding protein'. The amino acid composition for both proteins is reported. The nitrite reductase enzyme shows spectral characteristics indicative of the presence of c-type haem groups. Measurements at 610 nm indicate the presence of some high-spin haem groups at neutral pH. This haem subgroup undergoes a pH-linked high-spin - low-spin transition at alkaline pH. Approximately two of the six haem groups present within the enzyme bind CO with low affinity (KD = 0.4 mM). The enzyme also shows a range of redox activities with various inorganic reagents. The enzyme has been shown to exhibit dithionite reductase, oxygen reductase and CO2 reductase activities.

Amino Acids↗