bluuebunny/crossref_metadata_2025 huggingface dataset:
Microbiology of subgingival plaque from children with localized prepubertal periodontitis
Authors: Delaney J. E. , Kornman K. S.
Published: December 2007

Localized prepubertal periodontitis has been described as a host‐defect mediated form of bacterially induced periodontitis, with an early onset and rapid progression around a few teeth in children prior to puberty. To further our understanding of the etiology of this disease, we have examined the microbiological components of subgingival dental plaque in 9 children with localized prepubertal periodontitis to determine if patterns of putative pathogens existed, and have compared these results with those obtained from 4 children with no periodontitis. Subgingival plaque samples were plated onto a selective medium for Actinobacillus actinomycetemcomitans and onto a non‐selective medium for anaerobes, and the predominant cultivable microbiota of 2 sites per child was determined. The subgingival microbiota of children with localized prepubertal periodontitis clearly differs from non‐diseased children in the detection of high levels of several suspected pathogens, including A. actinomycetemcomitans, Bacteroides intermedius, Eikenella corrodens, and Capnocytophaga sputigena. These putative pathogens were found in various combinations. These findings suggest that localized prepubertal periodontitis is associated with specific subgingival bacteria which are generally not found in children without periodontitis.
The microbiota associated with successful or failing osseointegrated titanium implants
Authors: Mombelli A. , van Oosten M. A. C. , Schürch E. , Lang N. P.
Published: December 2007

Abstract In this study the microbiota associated with oral endosteal titanium hollow cylinder implants (ITI) was studied using microscopic, immunochemical and cultural methods. Samples from 5 edentulous patients with successfully incorporated implants serving as abutments for overdentures for more than one year were compared with samples from 7 patients with clinically failing implants. Unsuccessful sites were characterized by pocket probing depths of 6 mm or more, suppuration and visible loss of alveolar bone around the implant as visualized on radiographs. These sites harbored a complex microbiota with a large proportion of Gram‐negative anaerobic rods. Black‐pigmented Bacteroides and Fusobacterium spp. were regularly found. Spirochetes, fusiform bacteria as well as motile and curved rods were a common feature in the darkfield microscopic specimens of these sites. Control sites in the same patients harbored small amounts of bacteria. The predominant morphotype was coccoid cells. Spirochetes were not present, fusiform bacteria, motile and curved rods were found infrequently and in low numbers. The microbiota in control sites in unsuccessful patients and in site in successful patients were very similar. On the basis of these results, it is suggested that “periimplantitis” be regarded as a site specific infection which yields many features in common with chronic adult periodontitis.
Strains of mutans streptococci isolated in a population with extremely low caries prevalence are cariogenic in the hamster model
Authors: Emilson C. G. , Carlsson P. , Bratthall D.
Published: December 2007

Abstract Strains of Streptococcus mutans and Streptococcus sobrinus freshly isolated from a population almost free of caries were examined in hamsters maintained on a high sucrose diet. The strains were readily implanted and persisted in high numbers during the experimental period. The test strains all induced caries, with caries scores equal to or higher than those of a reference strain of S. mutans. The results indicate that the strains have inherent cariogenic properties which are revealed under a frequent exposure to high concentrations of sucrose in the diet.
Fibrillar strains of Streptococcus sanguis biotype I carry a surface protein which cross‐reacts with Antigen B from Streptococcus mutans Ingbritt
Authors: Wyatt Janet E. , Willcox Mark D. P. , Russell Roy R. B. , Handley Pauline S.
Published: December 2007

Eleven strains of Streptococcus sanguis biotype I carrying peritrichous fibrils and 4 strains with lateral tufts of fibrils were screened for crossreactivity with Antigen B (AgB), a protein with a molecular weight of 190,000, isolated from Streptococcus mutans Ingbritt. An antigen of similar molecular weight, which cross‐reacted serologically with AgB was detected by immunodiffusion, Western blotting and dot immuno‐binding in strains of S. sanguis biotype I with peritrichous fibrils but not in tufted strains. One strain, S. sanguis LGR2 carried dense fibrils (5+ density) and the gold label appeared to be associated with the fibrils. However, over all the strains there was no correlation between the density of fibrils and the amount of AgB labelling. Immunonegative staining confirmed the absence of AgB cross reactivity in the tufted strains of S. sanguis I, although the gold labelled the tuft fibrils non‐specifically. Antigen B was located on the cell surface of S. mutans Ingbritt and the label extended 45.9±9.9 nm from the cell wall although the strain was non‐fibrillar.
Importance of infection level of mutans streptococci for recolonization of teeth after chlorhexidine treatment
Authors: Emilson C. G. , Lindquist B.
Published: December 2007

The recolonization pattern of mutans streptococci after reduction by a 1 % chlorhexidine gel was followed in plaque samples of 8 subjects over a 26‐week period. Plaque samples from all available tooth surfaces were examined and the absence or presence of mutans streptococci was expressed on a scale from 0 to 4. Comparison of infection scores showed that heavily infected surfaces (Scores 3 and 4) occurred more frequently on molars than on other teeth before treatment. Such surfaces were most difficult to disinfect. Surfaces with pretreatment Scores 3 and 4 were more readily recolonized than surfaces less infected before treatment. On only about half of the tooth surfaces was the level of infection similar or identical with the pretreatment score after 26 weeks. The results indicate that tooth surfaces with high infection level of mutans streptococci are more rapidly recolonized by mutans streptococci even if these microorganisms have been suppressed to undetectable levels by the antimicrobial treatment.
Acute phase proteins in patients with chronic periapical granuloma before and after surgical treatment
Authors: Márion IIdikó , Kiss Csongor , Balla György , Szabó Terézia , Karmazsin Laszló
Published: December 2007

Márton I, Kiss C, Balla G, Szabó T, Karmazsin L. Acute phase proteins in patients with chronic periapical granuloma before and after surgical treatment.

Alpha‐ 1‐antitrypsin, alpha‐2‐macroglobulin, C‐reactive protein, haptoglobin and complement C3 component concentrations and oxidase activity of ceruloplasmin were studied in sera of 36 patients with chronic periapical granuloma before and after surgical treatment. Mean serum concentrations of the investigated proteins were slightly elevated at diagnosis, with the exception of haptoglobin. Alpha‐1‐antitrypsin and ceruloplasmin levels decreased significantly 7 days after apicectomy, the 4 other proteins were unchanged at this sampling. Each investigated protein decreased significantly 3 months after apicectomy. This is the first longitudinal study of “acute‐phase proteins” in chronic periapical granuloma.
A method for studying immunoglobulin synthesis by gingival cells
Authors: Stoufi Eleana D. , Taubman Martin A. , Lundqvist Carina A. , Smith Daniel J. , Ebersole Jeffrey L.
Published: December 2007

A method was developed for the culture and the measurement of immunoglobulin (Ig) synthesis by the relatively small numbers of mononuclear cells recoverable from periodontal disease tissues. In this system, we demonstrated that mononuclear cells actively synthesize Ig, remain viable and proliferate. The sensitivity of the quantitative Biotin‐Avidin enzyme linked immunoadsorbent assay (ELISA) procedure developed was tenfold greater than the conventional ELISA for IgG, IgM and IgA measurement. Studies of Ig synthesis by varying cell numbers indicated that 25,000 cells synthesized at least as much IgG, IgA and IgM as any higher number of cells (50‐500,000) tested. Varying the numbers of cells cultured also did not alter the kinetics of Ig synthesis in this system. The composition of the gingival mononuclear cells was studied. These cells consisted of approximately 21% T4 positive cells, 20% T8 positive cells, 42% Ig‐positive cells and 6% adherent, NSE‐positive cells. Ig synthesis by gingival and PB cells in the presence and absence of mitogen was used as an indicator of functional capability of the resident population derived from diseased periodontal tissues.
The earlier the colonization by mutans streptococci, the higher the caries prevalence at 4 years of age
Authors: Köhler Birgitta , Andréen Ingrid , Jonsson Berit
Published: December 2007

Seventy‐eight 4‐year‐old children, examined earlier for the presence of mutans streptococci at 4‐month intervals from 15 months of age, were recalled for recording of dental caries and salivary sampling. The saliva samples were analysed for the presence of mutans streptococci, including the species Streptococcus mutans and Streptococcus sobrinus and lactobacilli. The results showed that the earlier the mutans streptococci had been detected in the children, the higher the caries experience. Eighty‐nine percent of the children colonized at 2 years of age had experienced caries and had a mean dfs of 5.0 compared with 25% of the non‐colonized 4‐year‐olds with a mean dfs of 0.3. S. mutans was the predominant species. S. sobrinus was usually found in combination with S. mutans, except in 2 children where S. sobrinus was the only species detected. More children with multiple species had higher numbers of total mutans streptococci and a tendency to higher caries prevalence than children with only S. mutans.
Possible effect of medically administered antibiotics on the mutans streptococci: implications for reduction in decay
Authors: Loesche Walter J. , Eklund Stephen A. , Mehlisch David F. , Burt Brian
Published: December 2007

The decline in dental caries in children in North America, Scandinavia, Britain, Ireland and many Commonwealth nations is well documented. The multiple uses of fluoride can account for most, but not all, of this reduction. In this investigation, data are provided which suggest a relationship between antibiotic usage for medical purposes and a decline in both mutans streptococci (MS) and caries. Children attending Grades 1 and 2 in the Coldwater, Michigan school system and who reportedly never received antibiotics had significantly higher proportions of MS in the fissure plaques of first molars than subjects who received antibiotics. The level of decay in the primary dentition was inversely related to the reported usage of antibiotics. The frequent usage of antibiotics could reduce the incidence of dental caries by delaying the colonization of the teeth by the MS. This was evaluated by a prospective study in infants to determine what effect reported antibiotic usage would have on the colonization of newly erupting primary teeth. Only 2 of 10 infants cultured at 2 to 3 week intervals for periods up to 1 year after tooth eruption became colonized by the MS. One had never received antibiotics and the second had been on antibiotics for a single 5‐day period. Seven of the 8 non‐colonized infants had received antibiotic therapy for periods ranging from 10 to 181 days. Both the Coldwater study and the prospective study of infants suggested a relation between frequency of antibiotic usage for medical purposes and the MS levels on the teeth.
Comparison of two methods for the small‐scale extraction of DNA from subgingival microorganisms
Authors: Smith G. L. F. , Sansone C. , Socransky S. S.
Published: December 2007

Two methods were compared for the extraction of DNA from small numbers of bacterial cells. The first method involved lysis of cells with SDS in the presence of proteinase K, treatment with hexadecyltrimethyl ammonium bromide (CTAB) and precipitation of DNA with isopropanol. In the second method, DNA was extracted by treatment of the cells with guanidine hydrochloride (GHCl) and precipitated with ethanol. Thirty strains of representive gram positive and gram negative species were included in he study. Preparations derived from confluent growth on one‐quater of the surface of agar plates and from 108 cells were subjected to each extraction procedure and analyzed for their content of DNA, RNA and protein. The suitabilities of the resultant DNA for restriction enzyme digestion and biotin‐labelling by a random primer technique were also assessed. In general, the CTAB method yielded greater amounts of DNA than the GHCl procedure. RNA was present in most preparations of both types, but in amounts detectable only by agarose gel electrophoresis. The latter technique also revealed that DNA was not excessively sheared by either procedure. Protein was detected in some CTAB and GHCl preparations, but was not consistently associated with one or the other method. DNA obtained by both methods could be digested by the restriction enzyme EcoR 1. In addition, biotin‐labelled DNA probes prepared from CTAB and GHCl preparations were capable of hybridizing with homologous target DNA fixed to nitrocellulose. Since the CTAB method was consistently successful in recovering DNA from preparations containing 108 cells, it may be more suitable for the direct treatment of single colonies taken from primary isolation plates or plaque samples.
Detection of immunodominant antigens of periodontopathic bacteria in human periodontal disease
Authors: Watanabe H. , Marsh P. D. , Ivanyi L.
Published: December 2007

Sonicated whole cell extracts and outer membrane proteins (OMP) from Bacteroides gingivalis and Veillonella parvula were analysed by the immunoblot technique using sera from 103 patients with various forms of periodontal disease and from 31 control subjects. B. gingivalis sonicate contained 12 major bands (75‐14 kDa) of which the 46, 27 and 14 kDa antigens reacted more frequently with sera from adult and young adult patients with severe periodontitis compared with sera from controls and mild periodonlitis patients. The OMP of B. gingivalis contained 6 main antigens of 75, 57, 51, 46, 35 and 19 kDa m.w. The 46 kDa antigen reacted predominantly with sera from both groups of patients with severe periodontitis. V. parvula sonicate contained 11 antigens (76‐13 kDa) of which the 76 kDa antigen reacted more frequently with sera from controls and patients with mild periodontitis than with sera from patients with severe periodontitis. Conversely, antibodies to the 39 kDa antigen (absent from OMP) were specifically associated with severe periodontitis. Further monitoring of antibody responses to the 46, 27 and 14 kDa antigens of B. gingivalis and 39 kDa antigen of V. parvula may be of importance for the assessment of severity of human periodontal disease.
Experimental infections by Bacteroides gingivalis in non‐immunized and immunized rabbits
Authors: Dahlén Gunnar , Slots Jørgon
Published: December 2007

The interactions between Bacteroides gingivalis and systemic antibodies were studied in tissue cages implanted in the backs of New Zealand white rabbits. Infectivity was evaluated according to clinical signs and to leukocyte and bacterial counts in material aspirated from the tissue cages. Pre‐ and post‐inoculation antibody levels to sonicated whole bacterial cells were determined by enzyme‐linked immunosorbent and agar immunodiffusion assays. Rabbits immunized against B. gingivalis and then challenged with pure cultures of B. gingivalis revealed complete elimination or markedly lower postinoculation bacterial counts and considerably weaker tissue reactions than non‐immunized animals. B. gingivalis co‐inoculated with Actinobacillus actinomycetemcomitans caused significantly more severe infections than observed in monoinfected animals. The present results suggest that the immune system acting through systemic antibodies and/or cellular mechanisms may modulate the pathogenic potential of infecting periodontal pathogens.
Quantitative significance of IgE‐producing plasma cells and tissue distribution of mast cells in apical periodontitis
Authors: Márton Ildikó , Nemes Zoltán , Harmati Sándor
Published: December 2007

A total of 30 dental periapical lesions were used for estimating the frequency of IgE‐producing plasma cells by the unlabelled antibody peroxidase antiperoxidase method. Mast cells were detected in adjacent sections by the naphthol‐AS‐D‐chloroacetate esterase technique. IgE‐producing plasma cells were present in the central granulation tissue in 26 of the 30 specimens. The average ratio of IgE‐containing plasma cells was 0.22% as related to all plasma cells. The central granulation tissue was devoid of mast cells, but numerous mast cells were found in the fibrous capsule of periapical lesions.
Probe‐specific DNA fingerprinting applied to the epidemiology of localized juvenile periodontitis
Authors: DiRienzo Joseph M. , Cornell Susan , Kazoroski Lynn , Slots Jørgen
Published: December 2007

Although Actinobacillus actinomycetemcomitans has been recognized as a primary etiological agent in localized juvenile periodontitis, questions remain concerning the source of infection, mode of transmission, and relative virulence of strains. DNA fingerprinting analysis, using a randomly cloned chromosomal DNA fragment as a probe, revealed that previously characterized strains of A. actinomycetemcomitans displayed significant restriction site heterogeneity which could be applied to the typing of clinical isolates of this bacterium such that individual strains or variants could be traced within subjects from localized juvenile periodontitis families. Hybridization data derived from an analysis of bacterial isolates obtained from families participating in an ongoing longitudinal study of the disease showed that a single individual could be infected with more than one strain or variant of A. actinomycetemcomitans and that various members of the same family could harbor different strains or variants of the bacterium. In several cases the clinical isolates were matched to characterized laboratory strains by comparing hybridization patterns generated by digestion of the DNA with several restriction enzymes in independent reactions. Thus, probe‐specific DNA fingerprinting of A. actinomycetemcomitans will permit us to determine if particular strains or variants are frequently associated with sites of periodontal destruction. Attention could then be focused on determining the virulence properties of those strains or variants that have in vivo significance.
Salivary caries‐related tests as predictors of future caries increment in teenagers. A three‐year longitudinal study
Authors: Alaluusua S , Kleemola‐Kujala E , Grönroos L , Evälahti M
Published: December 2007

The aim of the study was to evaluate the capability of caries‐related salivary tests and a test based on past caries experience (baseline DPS) to select persons at high risk for caries. The subjects (n = 122) were 12–17 years old at the beginning of the study. Caries was registered and salivary samples were taken annually during the 3‐study period. The 3‐year caries increment was positively correlated to the baseline DPS (r = 0.46, p < 0.001), salivary level of mutans streptococci (r = 0.30, p < 0.001) and lactobacilli (r = 0.30, p < 0.001), and combined level of mutans streptococci and lactobacilli (r = 0.39, p < 0.001) and negatively correlated to the buffering capacity of saliva (r =−0.22, p < 0.05). Tests based on either past caries experience or mutans streptococci or lactobacilli levels alone were not efficient in selecting persons at high risk for caries. Among the tests, DPS was the most sensitive and specific. A combination of either microbial test and DPS was more efficient to select persons at risk than various alternatives alone. The sensitivity was 84% and the specificity 62% for the combination of lactobacilli test and DPS and 71% and 79% respectively for the combination of mutans streptococci and DPS. In the former combination the positive prediction value was 43% and in the latter 56%.
Isolation and characterization of lipopolysaccharide from Centipeda periodontii ATCC 35019
Authors: Kokeguchi Susumu , Tsutsui Osamu , Kato Keijiro , Matsumura Tomohiro
Published: December 2007

Lipopolysaccharide (LPS) was extracted from cells of Centipeda periodontii ATCC 35019 by a hot phenol‐water method, purified by nuclease treatment and by repeated ultracentrifugations. The LPS was composed of 21.7% hexose, 9.1% hexosamine, 10.3% fatty acid, 0.5% protein, 2.5% phosphorus, 4.3% 2‐keto‐3‐deoxyoctonate(KDO) and 2.3% heptose. The major fatty acids of the LPS were 3OH C13:0 and C13:0. C. periodontii LPS was able to gelatinize Limulus amebocyte and to produce the local Schwartzman reaction in rabbits. LPS from C. periodontii exhibited strong immunobiological activities, mitogenicity on splenocytes of C3H/HeN mice, and stimulation of interleukin 1 (IL‐1) production in peritoneal macrophages of C3H/HeN mice.
Comparative studies of the outer membranes of Bacteroides gingivalis, strains ATCC 33277, W50, W83,381
Authors: Kennel Wiebke , Holt Stanley C.
Published: December 2007

Outer membrane fractions from Bacteroides gingivalis strains ATCC 33277, 381, W50, and W83 were isolated by French pressure cell disruption and the distribution of major and minor proteins was determined by SDS‐PAGE electrophoresis after treatment with 2% Sarkosyl and 2% Triton X‐100. Heat‐modifiability of the outer membrane proteins (OMPs) from these B. gingivalis strains was also determined after treatment at 100°C and analysis by both 1‐ and 2‐dimension‐al SDS‐PAGE. The distribution of the OMPs on the surface of these B. gingivalis strains was determined by 125I labelling. For the most part the OMPs of B. gingivalis presented a complex distribution, with OMPs observed between 123kD and 13kD. While the distribution of the OMPs was strain specific, OMPs common to all of the strains were observed. Two percent Sarkosyl treatment of the OMs at room temperature resulted in the solubilization of approximately 60% of the OMP. The Sarkosyl‐insoluble MOMPs had relative molecular weights between 110kD and 20kD. Many of the OMPs which were separated at room temperature were heat‐modified at either 65°C or 100°C. Heating of the OMs at 100°C resulted in the heat modification of the majority of those OMPs observed at room temperature. Sarkosyl‐ 100°C OMs displayed MOMPs at apparent molecular weights between 90kD and 15kD. Radioiodination of the B. gingivalis strains ATCC 33277, 381, W83 and W50 revealed between 7 and 14 MOMPs at the cell surface depending upon the strain. The complexity of the OM of these B. gingivalis strains indicated the possibility of identifying and separating those OMPs involved in a variety of biological functions, including virulence, transport, and cell interaction.
Three‐dimensional structure of the surface layer of Wolinella recta
Authors: Dokland Terje , Olsen Ingar , Farrants George , Johansen B.V.
Published: December 2007

The three‐dimensional structure of the crystalline surface layer (S‐layer) of Wolinella recta ATCC 33238T, a gram‐negative, anaerobic periodontopathogen, was determined to 3.8 nm resolution by electron microscopy and digital image processing. The S‐layer protein is closely associated with the outer bacterial membrane, and shows p6 symmetry with lattice spacing and thickness of 21 nm and 15 nm, respectively. The funnel‐shaped subunits consist of 6 heavy domains located round a common base at the sixfold axis, and communicate with the adjacent subunits through a lighter domain at the threefold axis (M6C3 arrangement).
Purification and characterization of a 43‐kDa protease of Bacteroides gingivalis
Authors: Fujimura Setsuo , Nakamura Takeshi
Published: December 2007

From the culture supernatant of Bacteroides gingivalis ATCC 33277, a thiol protease was purified to homogeneity by fractional ammonium sulfate precipitation, ion‐exchange chromatography, gel filtration, and isoelectric focusing. Its molecular weight was 43 kDa and showed similar enzymatic properties to a 300‐kDa protease that was previously characterized.
The formation of hydrogen sulfide and methyl mercaptan by oral bacteria
Authors: Persson Sten , Edlund Maj‐Britt , Claesson Rolf , Carlsson Jan
Published: December 2007

The capacity to form volatile sulfur compounds was tested in bacteria isolated from subgingival microbiotas and in a representative number of reference strains. A majority of the 75 tested oral bacterial species and 7 unnamed bacterial taxa formed significant amounts of hydrogen sulfide from L‐cysteine. The most active bacteria were found in the genera Peptostreptococcus, Eubacterium, Selenomonas, Centipeda, Bacteroides and Fusobacterium. Methyl mercaptan from L‐methionine was formed by some members of the genera Fusobacterium. Bacteroides. Porphyfomonas and Eubacterium. When incubated in serum for 7 d, the most potent producers of hydrogen sulfide were Treponema denticola and the black‐pigment‐ed species, Bacteroides iniermedius, Bacteroides loescheii, Porphyromonas endodontalis and Porphyromonas gingivalis. P. endodontalis and P. gingivalis also produced significant amounts of methyl mercaptan in serum. No other volatile sulfur compound was detected in serum or in the presence of L‐cysteine and L‐methionine. These findings significantly increase the list of oral bacteria known to produce volatile sulfur compounds.
Doxycycline‐resistant bacteria in periodontally diseased individuals after systemic doxycycline therapy and in healthy individuals
Authors: Fiehn Nils‐Erik
Published: December 2007

The occurrence of doxycycline‐resistant bacteria was examined in subgingival Plaque and on the tonsils of 12 periodontally healthy and 12 periodontally diseased individuals. The healthy group was examined 6 times at intervals of One month. The diseased group was examined before and 1, 5, 15, 26, 39, and 52 weeks after conventional periodontal therapy supplemented with systemic doxycycline for 3 weeks. The occurrence of doxycycline‐resistant bacteria in the healthy group varied on average between 2.0% and 6.6% in subgingival plaque and Between 3.0% and 12.4% in the tonsil samples over a 6‐month period. In the Ceased group the percentage of resistant bacteria increased from 10–20 times Or tonsil and subgingival plaque, respectively. About half a year after therapy The values returned to the baselines. For both groups the morphological distributions of resistant bacteria were similar and unaffected by the doxycycline therapy.
Oxygen‐dependent lactate utilization by Actinomyces viscosus and Actinomyces naeslundii
Authors: van der Hoeven J. S. , van den Kieboom C. W. A.
Published: December 2007

Actinomyces viscosus and Actinomyces naeslundii were grown in chemostat cultures with glucose or lactate as the sole sources of energy. Growth on lactate was dependent on oxygen. Lactate was oxidised partly to acetic acid. As judged from the low carbon recoveries in acidic degradation products, it is concluded that a stubstantial part of the lactate was oxidised to carbon dioxide. Assuming that 1 ATP is generated in the transfer of an electron pair to oxygen. YATP values of 10–11 were calculated from the molar growth yield on lactate and product formation. Although all cell 3 test strains oxidised lactate, one strain could not grow on lactate as the sole source of energy. The rate of oxygen uptake with lactate as substrate was higher for cells grown aerobically than of cells grown anaerobically, indicating that lactate oxydation was induced by oxygen. It is reason‐le to assume that lactate oxidation is mediated either by lactate dehydrogenase or lactate oxidase, but the pathway in Actinomyces sp. is not yet known. Lactate ‐consumption may be an important trait of Actinomyces sp. that live in an environment limited in energy sources for most of the time.
DNA probe detection of periodontal pathogens in HIV‐associated periodontal lesions
Authors: Murray P. A. , Winkler J. R. , Peros W. J. , French C. K. , Lippke J. A.
Published: December 2007

Recent studies have shown that an atypical gingivitis and a rapidly progressive periodontal disease may be early‐occurring opportunistic infections associated with human immunodeficiency virus (HIV) infection. This study examined the prevalence of selected periodontal pathogens associated with these HIV‐related periodontal lesions. Subgingival plaque samples were obtained from both HIV‐seronegative and HIV‐seropositive homosexual men and from presumably uninfected heterosexual men. DNA probes were used to detect Actinobacillus actinomycetemcomitans, Bacteroides intermedius, Bacteroides gingivalis, Eikenella corrodens and Wolinella recta in the plaque. The healthy sites in both the seronegative and seropositive homosexual groups showed a greater prevalence of all test bacteria, except for E. corrodens, than did the heterosexual group. HIV‐associated periodontitis sites showed a microbial profile qualitatively similar to that of conventional periodontitis, except that B. gingivalis was more prevalent in conventional periodontitis. In contrast, HIV‐associated gingivitis sites exhibited a greater prevalence of all bacteria tested than conventional gingivitis sites. In fact, HIV gingivitis generally showed a bacterial profile similar to that of the HIV periodontitis lesions, except that W. recta was significantly more prevalent in HIV periodontitis. These data suggest that the HIV gingivitis lesion is a precursor to HIV periodontitis. Thus, early identification and prophylactic treatment of high‐risk individuals may prevent the destruction of periodontal tissues.
Aspartate and asparagine as electron acceptors for Wolinella recta
Authors: Ohta Hiroyuki , Gottschal Jan C. , Fukui Kazuhiro , Kato Keijiro
Published: December 2007

Since fumarate and nitrate are not usually available in the oral ecosystem, it was investigated whether aspartate and asparagine could be used as alternative electron acceptors by Wolinella recta, which is strictly dependent on a respiratory metabolism with formate or H2 as electron donors. Both aspartate and asparagine were indeed shown to support growth of W. recta with formate as electron donor. Fermentative growth with aspartate alone was not possible. Succinate was the major end‐product and was formed in equimolar quantities with respect to the amount of formate consumed. The consumption of aspartate and asparagine, on a molar basis, was 10–30% higher than that of formate. Cell‐free extracts were prepared from cells grown with formate 4‐fumarate, formate + aspartate, formate + asparagine, and formate + fumarate + aspartate. All these extracts contained high activities of asparaginase, aspartate ammonia‐lyase and fumaratereductase, but no significant activity of aspartate aminotransferase was detected, indicating that fumarate was synthesized directly from aspartate and subsequently reduced to succinate. Based on these results it seems likely that aspartate and asparagine can serve as natural electron acceptors for W. recta in periodontal lesions in which proteolytic bacteria abound.
Aerobic and anaerobic microbiology of periapical abscess
Authors: Brook Itzhak , Frazier Edith H. , Gher Marlin E.
Published: December 2007

Aspirates of pus from periapical abscesses in 39 patients were studied for aerobic and anaerobic bacteria. Bacterial growth was present in 32 specimens. A total of 78 bacterial isolates (55 anaerobic and 23 aerobic and facultative) were recovered, accounting for 2.4 isolates per specimen (1.7 anaerobic and 0.7 aerobic and facultatives). Anaerobic bacteria only were present in 16 (50%) patients, aerobic and facultatives in 2 (6%), and mixed aerobic and anaerobic flora in 14 (44%). The predominant isolates were Bacteroides spp. (23 isolates, including 13 Bacteroides melaninogenicus group). Streptococcus spp. (20), anaerobic cocci (18), and Fusobacterium spp. (9). Beta‐lactamase‐producing organisms were recovered from 7 of the 21 (33%) specimens that were tested. This study highlights the polymicrobial nature and importance of anaerobic bacteria in periapical abscess.
Complement factor D̄‐like activity of Porphyromonas gingivalis W83
Authors: Schenkein Harvey A.
Published: December 2007

Porphyromonas gingivalis is a proteolytic gram‐negative anaerobic bacterium that is frequently isolated from lesions of human periodontal disease. Previous studies have shown that P. gingivalis strain W83 inactivates C3 in pooled normal human serum (NHS) by a mechanism that is inhibitable by EDTA, yet it degrades purified complement proteins by a mechanism that is not EDTA‐inhibitable. Furthermore, during complement activation, only a small number of C3 molecules accumulate on the surface of this organism unless the bacteria are treated with the protease inhibitor TLCK prior to complement activation. The hypothesis was tested that P. gingivalis W83 contains protease activity mimicking that of complement factor D, thus enabling it to activate C3 in serum without significant C3 accumulation on the cell surface. It was first noted that incubation of P. gingivalis W83 in absorbed human serum that was depleted of factor D resulted in C3 consumption that was reversed in the presence of the protease inhibitor TLCK. To directly demonstrate that factor B‐dependent C3 consumption occurs in the absence of factor D, P. gingivalis W83 was incubated with purified C3 or a mixture of C3 and B. Although some proteolysis of C3 was noted, increased C3 consumption was noted in mixtures containing both C3 and B. This increment in C3 consumption was inhibited by both EDTA and TLCK. Furthermore, the addition of purified factor H to this mixture inhibited the increment in C3 consumption, indicating that a C3 convertase was probably formed. Following incubation of P. gingivalis W83 in a mixture of C3 + B containing 125I‐C3, cleavage of 125I‐C3 and formation of C3b was detectable by SDS‐PAGE and autoradiography; C3 cleavage was inhibited by addition of H. This demonstrates the activity of a functional C3‐cleaving enzyme in the absence of factor D that, like the alternative pathway C3 convertase, depends on factor B and Mg++ and is inhibited by factor H. Thus, P. gingivalis proteases that are inhibitable by TLCK substitute for factor D and initiate C3 consumption in serum, using factor B of the alternative complement pathway.
Effect of initial treatment of chronic inflammatory periodontal disease on the frequency of peripheral blood T‐lymphocytes specific to periodontopathic bacteria
Authors: Mahanonda R. , Seymour G. J. , Powell L. W. , Good M. F. , Halliday J. W.
Published: December 2007

Limit dilution analysis (LDA) was used to determine the effect of initial treatment of chronic inflammatory periodontal disease on the frequency of periodontopathic bacteria‐specific T‐cells in peripheral blood. Eleven marginal gingivitis (MG) and 8 adult periodontitis (AP) subjects took part in the study. The proliferative T‐lymphocyte precursor (PTL‐P) frequencies to Porphyromonas gingivalis and Actinomyces viscosus were determined using LDA and Poisson statistics both before and after treatment. Tetanus toxoid was used as a control antigen. Treatment resulted in a significant reduction in clinical disease parameters in both groups. The median peak PTL‐P frequency for P. gingivalis was significantly higher in the AP group compared with the MG group before treatment. This was not the case after treatment nor with A. viscosus. In the MG group the median peak PTL‐P frequency with both P. gingivalis and A. viscosus declined as a result of treatment. Although this decline was not statistically significant it may indicate an antigen‐specific response in this group. In the AP group the median peak PTL‐P frequency with P. gingivalis before treatment was 83.76 × 10−6 (approximately 1 in 12,000) and after treatment it was 36.17 × 10−6 (approximately 1 in 28,000). Dose‐response relationships showed at each concentration of organisms/ well this trend for a decline in PTL‐P frequency after treatment, suggesting that any increased responsiveness to this organism in this group may be largely antigen‐specific. However, there was no difference in this group in the median peak PTL‐P frequency with A. viscosus before and after treatment. This, together with the low PTL‐P frequency to A. viscosus, suggests that any increased responsiveness to this organism in this group may be non‐specific.
Mutans streptococci in saliva and interdental spaces after topical applications of an antibacterial varnish in schoolchildren
Authors: Petersson Lars G. , Maki Yoshinobu , Twetman Svante , Edwardsson Stig
Published: December 2007

The effect of a chlorhexidine‐containing varnish on the levels of mutans streptococci in saliva and in interdental spaces was investigated in 33 15‐year‐old schoolchildren. Each child was treated with an active (1% chlorhexidine; 1% thymol) and a placebo varnish preparation following the split‐mouth technique. The varnishes were applied twice in small amounts into upper interdental areas with a 2‐d interval. Mutans streptococci in saliva and interdental plaque was sampled and enumerated during 3 months. The results showed an immediate reduction of the number of interdental mutans streptococci on both test and placebo side after the varnish applications. The levels, however, were significantly lower in the test quadrants compared with the placebo‐treated sides after 8, 30 and 90 d. Thus, the findings indicate a slower recolonization in interdental spaces treated with the active preparation. The levels of mutans streptococci in saliva were significantly reduced 1 and 3 months after varnish treatment, suggesting a long‐term effect of the antibacterial varnish.
The immunogenicity of outer membrane proteins of haemin‐depleted Porphyromonas (Bacteriodes) Gingvilis W50 in periodontal desease
Authors: Papaioannou S. , Marsh P. D. , Ivanyi L.
Published: December 2007

The antigens from outer membrane protein extracts of Porphyromonas gingivalis (W50), grown under different haemin concentrations, were examined for binding with serum antibodies from patients with severe progressive periodontitis or from periodontally healthy control subjects. P. gingivalis was grown under haemin limitation (0.33 μg/ml) and haemin excess (2.5 μg/ml) conditions in a chemostat at a mean generation time of 6.9 h, at pH 7.5. Sarkosyl‐insoluble fractions of outer membrane proteins from P. gingivalis were prepared, and analysed by sodium dodecyl sulphate‐polyacrylamide gel electrophoresis (SDS‐PAGE) and immunoblot techniques. The SDS‐PAGE analysis of the outer membrane of haemin‐limited P. gingivalis identified several new protein components, or changed expression of bands compared with cells grown under haemin excess. Immunoblot analysis showed IgG antibodies to 2 haemin deprivation‐induced proteins in patients with severe progressive periodontitis, but not in the control sera. These results confirm the immunogenicity of some of the haemin‐regulated outer membrane proteins of P. gingivalis in severe progressive periodontitis.
Human lactoferrin binding to Porphyromonas gingivalis, Prevotella intermedia and Prevotella melaninogenica
Authors: Kalfas Sotirios , Andersson Mats , Edwardsson Stig , Forsgren Arne , Naidu A. Satyanarayan
Published: December 2007

Human isolates of Porphyromonas gingivalis (n= 16), Prevotella intermedia n= 82) and Prevotella melaninogenica (n= 18) from diseased periodontal pockets were examined for interaction with human lactoferrin (HLf) in a standardized 125I‐labeled protein binding assay. The highest HLf binding was found in P. intermedia strains, followed by P. gingivalis and P. melaninogenica. Further characterization of the interaction was performed with 1 representative strain from each species. HLf binding to P. gingivalis reached a saturation instantly and was optimal at pH 5.0–6.5. The corresponding values for P. melaninogenica were 90 min and pH 3.0–5.5. The HLf binding to the 2 strains seem to be nonspecific. In contrast, P. intermedia demonstrated specific binding, and a timesaturability within 60 min with an optimal uptake at pH 6.0–7.5. Scatchard analysis implied 45,000 receptors per cell with an affinity constant of 5.5 × 10−7 M on P. intermedia strain 4H. The binding capacity in all 3 strains was affected by the culture medium. HLf binding components in these strains were susceptible to heat or proteases. Binding was eliminated in P. gingivalis and was enhanced in P. intermedia and P. melaninogenica by periodate treatment. Unlabeled HLf or bovine lactoferrin effectively displaced labeled HLf binding. Various proteins and carbohydrates did not inhibit HLf binding. Our data suggest that HLf binds to these periodontitis‐associated species and that this mechanism is distinct from the previously known ligand interactions in oral bacteria.
Antifungal activities of salivary histidine‐rich polypeptides against Candida albicans and other oral yeast isolates
Authors: Rayhan R. , Xu L. , Santarpia R. P. , Tylenda C. A. , Pollock J. J.
Published: December 2007

Twenty‐six oral yeast isolates from 26 donors were tested for their susceptibility to salivary histidine‐rich polypeptide‐4 (HRP‐4) in blastospore viability assays. HRP‐4 was observed to inhibit blastospore division in all of the yeast isolates, although inhibition was variable depending upon both species and strain tested. Nine species of Candida and 2 strains of Trichosporon pullulans were included in the study. No significant differences in susceptibility to HRP‐4 could be seen, irrespective of where in the oral cavity the yeast isolate was obtained.
Phenotypic characteristics and DNA relatedness in Prevotella intermedia and similar organisms
Authors: Fukushima H. , Moroi H. , Inoue J. , Onoe T. , Ezaki T. , Yabuuchi E. , Leung K.‐P. , Walker C. B. , Clark W. B. , Sagawa H.
Published: December 2007

We have recently isolated from the gingival pockets, periapical lesions and saliva some anaerobic gram‐negative, black‐pigmented rods. Many of these isolates exhibited phenotypic characteristics similar to Prevotella intermedia (Bacteroides intermedius). However, several of these isolates, although resembling P. intermedia in most of the phenotypic expressions, were capable of fermenting lactose, a biochemical characteristic atypical of P. intermedia. These atypical clinical isolates (strains capable of fermenting lactose) and isolates exhibiting more typical phenotypic characteristics (i.e., lactose nonfermenting) were definitively identified as P. intermedia by DNA‐DNA hybridization using a photoprobe biotin method. Quantitative hybridization of clinical isolates with labeled DNA of P. intermedia‐type strains (ATCC 25611 and ATCC 33563) showed that almost all the clinical strains isolated from disease sites of adults belonged to the ATCC 25611 group, whereas strains isolated from the saliva of children belonged to the ATCC 33563 group. These data, together with the phenotypic characterization of the isolates, suggested that P. intermedia is a heterogeneous species both phenotypically and genetically.
DNA probes for detection of cariogenic Streptococcus mutans
Authors: Smorawinska M. , Kuramitsu H. K.
Published: December 2007

Streptococcus mutans has been identified as the principal etiological agent in human denial caries. Therefore, the specificity and sensitivity of 3 potential gene probes derived from S. mutans GS5 have been examined as potential reagents for detecting the cariogenic bacteria. The gene probes derived from the cloned gtfB, gtfD and ftf genes were examined in Southern blots with a panel of representative oral bacteria. The gtfB and ftf genes were apparently specific for S. mutans under high‐stringency hybridization conditions. However, the gtfD gene fragment did cross‐hybridize with the DNA from other mutans streptococci. These results suggest that gtfB and ftf gene fragments may be used as specific probes for S. mutans.
Hydrogen sulfide and methyl mercaptan in periodontal pockets
Authors: Persson S.
Published: December 2007

A sensitive gas chromatographic method was developed to determine the amounts of volatile sulfur compounds in gingival fluid. Hydrogen sulfide was the predominant volatile sulfur compound and was detected in 61 out of 79 studied periodontal pockets. Methyl mercaptan was found in about 20% of the pockets. No other volatile sulfur compounds were detected. The highest concentration of hydrogen sulfide in gingival fluid was 1.9 mmol/liter, and of methyl mercaptan 0.16 mmol/liter.
The role of interleukin‐1α in the pathogenesis of periapical bone destruction in a rat model system
Authors: Wang C.‐Y. , Stashenko P.
Published: December 2007

To identify the mediators that stimulate periapical bone resorption following infection, a rat model system was used in which active (rapid) and chronic (slow) phases of bone destruction can be distinguished. Extracts of inflammatory tissues from active lesions contained high levels of bone‐resorbing activity, which was destroyed by proteinase K and heat (70°C), but was unaffected by polymyxin B, indicating the presence of protein mediator(s) rather than lipopolysaccharide. Fast‐performance liquid chromatography gel filtration of extracts of active lesions demonstrated that most activity was associated with macromolecules of MW 30–60 kDa and 15–20 kDa, consistent with bone resorptive cytokines, including interleukin 1 (IL‐I) and tumor necrosis factor (TNF). Inhibition with cytokine‐specific antisera demonstrated that resorbing activity in active lesions was significantly neutralized by anti‐IL‐1β, whereas anti‐IL‐1/α, anti‐TNFα and anti‐TNFα had only slight effect. A lower amount of resorbing activity was present in extracts of chronic lesions, which was also neutralized only by anti‐IL‐1α. Inflammatory tissue explants produced more IL‐1α than 1L‐1βin vitro, confirming findings with extracts, and high levels of IL‐1α were present in active lesions by radioimmunoassay. These data indicate that bone resorption stimulated by bacterial infection is primarily mediated by IL‐1α in this model. The similarity of cytokines in active and chronic lesions suggests that quantitative rather than qualitative differences in these mediators may account for lesion progression.
Identification of plasmids in Actinobacillus actinomycetemcomitans and construction of intergeneric shuttle plasmids
Authors: LeBlanc D. J. , Lee L. N. , Abu‐AI‐Jaibat A. R. , Sreenivasan P. K. , Fives‐Taylor P. M.
Published: December 2007

A collection of 39 isolates of Actinobacillus actinomycetemcomitans, obtained from laboratories located in 5 different geographical regions of the United States, was examined for the presence of plasmid DNA. Only 2 of the strains examined, designated VT736 and VT745, harbored detectable plasmids. Strain VT736 contained a 1.9 kb plasmid species (pVT736‐1) and a larger (>30 kb) species (pVT736‐2). Both plasmids were detected in the covalently closed circular DNA fraction of dye buoyant density gradients. However, only the smaller plasmid was observed in agarose gels containing plasmid‐enriched cell lysates prepared by a rapid screening procedure. Strain VT745 contained a single, 24 kb, plasmid (pVT745) that was observed consistently in plasmid‐enriched lysates, as well as in the plasmid band of dye buoyant density gradients. A restriction endonuclease map of pVT736‐l was constructed. The plasmid contained one site each for the enzymes HincII, KpnI and XhoI, located 600 to 700 bp from each other on the pVT736‐1 map. HincII‐digested pVT736‐1 DNA could not be cloned in Escherichia coli. However, intact pVT736‐1 digested with KpnI or XhoI could be cloned in E. coli on pUC19 or pGEM7Zf(‐), respectively. KpnI‐digested pVT736‐1 was cloned in both orientations on pUC19, but XhoI‐digested pVT736‐1 was clonable in only one orientation on pGEM7Zf(‐). Each of the 3 types of chimeric plasmid constructs provided a potential A. actinomycetemcomitans/E. coli shuttle plasmid for the development of a genetic transfer system in A. actinomycetemcomitans.