bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of the E test for antimicrobial susceptibility testing of Actinobacillus actinomycetemcomitans
Authors: Pajukanta R. , Asikainen S. , Saarela M. , Alaluusua S. , Jousimies‐Somer H.
Published: December 2007

The E test was compared with an agar dilution method for antimicrobial susceptibility testing of Actinobacillus actinomycetemcomitans on Mueller‐Hinton Haemophilus test medium. Eighty recent isolates of A. actinomycetemcomitans from 40 subjects and 3 reference strains were studied. Excellent agreement was obtained between the E test and the agar dilution test for benzylpenicillin (98.8%), ampicillin (97.5%), cefaclor (100%), cefuroxime (100%), tetracycline hydrochloride (100%) and ciprofloxacin (98.7%); 76.0% agreement was obtained for metronida‐zole and only 5.2% for cotrimoxazole. This study indicates that the E test is a reliable method to determine minimal inhibitory concentrations of antimicrobials against A. actinomycetemcomitans, except for metronidazole and cotrimoxazole.
The association of carious dentin microflora with tissue changes in human pulpitis
Authors: Massey W. L. K. , Romberg D. M. , Hunter N. , Hume W. R.
Published: December 2007

Correlations were sought between the number and type of microorganisms recovered from sampled carious dentin and the cellular responses observed in dental pulpal tissues from a sample of 65 vital, carious teeth extracted from adult humans who had declined the option of tooth restoration. Standardized homogenates of carious dentin were plated using selective and nonselective media under anaerobic and microaerophilic conditions. Pulpal responses were characterized histopathologically on the basis of the nature of the cellular infiltrate and the extent of degenerative changes. A significant association between the number of Prevotella intermedia and Prevotella melaninogenica in carious dentin and extensive, principally mononuclear, inflammatory infiltration was evident despite a high degree of complexity and intersubject variability in the microbial flora. There was no apparent association between other microorganisms or total microbial load and the histopathological category.
Microbiology of early supragingival plaque development after delmopinol treatment
Authors: Collaert B. , Edwardsson S. , Attström R. , Hase J. C. , Åström M.
Published: December 2007

The aim of this double blind, cross‐over, microbiological study was to compare the effect of topical application of the plaque control agent 0.5% delmopinol HCl with placebo on early supragingival plaque formation. Six subjects underwent 7 periods (0.5, 1, 2, 8 and 24 h and 3 and 7 days) of placebo and delmopinol application, respectively. At the start of each study period the teeth were professionally cleaned and 2 ml of placebo and delmopinol 0.5%, respectively, were applied on all teeth (twice daily for periods lasting 24 h or more). At the end of each period, supragingival plaque samples of one upper and one lower buccal tooth surface were collected separately and cultured on anaerobically incubated Brucella blood agar, on aerobically incubated blood agar and on selective media for the enumeration of Streptococcus spp., Haemophilus spp., Actinomyces spp., Veillonella spp., Neisseria spp. and Fusobacterium spp. The total anaerobic cultivable microflora after delmopinol use was 10–100 times lower than after placebo use. Compared with placebo, the proportion of cultivable aerobes (61.3%), Streptococcus spp. (104.8%) and Haemophilus spp. (82.3%) increased and the proportion of Actinomyces spp. (86.1%), Veillonella spp. (60.5%), Neisseria spp. (96.9%) and Fusobacterium spp. (60.6%) decreased after 7 days. Short‐term application of 0.5% delmopinol HCl on supragingival dental plaque regrowth resulted in a reduction of the number of cultivable microorganisms in the plaque and produced a shift in the cultivable plaque composition.
Chemotaxis and degranulation of polymorphonuclear leukocytes in the presence of sulfide
Authors: Persson S. , Claesson R. , Carlsson J.
Published: December 2007

In polymicrobial infections such as periodontal disease, the polymorphonuclear leukocytes (PMN) may have to work in the absence of oxygen and in the presence of significant levels of hydrogen sulfide. There are conflicting results reported on the chemotactic capacity of PMN under anaerobic conditions. It is not known whether PMN are able to migrate and release the contents of their granules in the presence of sulfide. PMN were exposed to various levels of sulfide and their chemotaxis and degranulation were studied when they were stimulated with N‐formyl‐inethionyl‐leucyl‐phenylalanine or zymosan‐activated serum. Chemotaxis was evaluated with the agarose method. The release of granule markers, lactoferrin and myeloperoxidase, was evaluated with enzyme‐linked immunosorbent assay. PMN had similar capacity for chemotaxis under aerobic and anaerobic conditions. The migration of PMN was only to a minor extent inhibited by 1–2 mM sulfide. The release of lactoferrin and myeloperoxidase was the same under aerobic and anaerobic conditions and was not significantly influenced by sulfide. PMN seem to be very well suited to defend the tissue against bacteria under the harsh conditions prevailing in the periodontal pocket.
Campylobacter rectus in human periodontitis
Authors: Rams T. E. , Feik D. , Slots J.
Published: December 2007

Campylobacter rectus (formerly Wolinella recta) in periodontitis lesions was studied relative to age and sex distribution, relationship to disease‐active periodontitis, response to periodontal debridement and in vitro antimicrobial susceptibility. Subgingival C. rectus was collected with paper points, transported in VMGA III and plated onto nonselective enriched brucella blood agar and Hammond's selective medium for C. rectus, both incubated anaerobically. C. rectus was recovered from 80% of 1654 periodontitis patients. Although the organism showed similar age and sex occurrence, its proportional recovery in culture‐positive adults was inversely related to increasing age (r= 0.999, P<0.001). The organism was positively associated (summary odds ratio = 2.95) with disease activity in a 24‐month longitudinal study of 93 adult periodontitis patients on maintenance therapy. C. rectus decreased from 8.2% to 0.7% following local periodontal debridement of 20 culture‐positive adult periodontitis patients. The organism exhibited high in vitro susceptibility to therapeutic levels of tetracycline hydrochloride, metronidazole, penicillin G and ciprofloxacin. These findings further delineate the epidemiology and potential pathogenic role of C. rectus in human periodontitis.
Observation of an unusually large spirochete in endodontic infection
Authors: Dahle U. R. , Tronstad L. , Olsen I.
Published: December 2007

Spirochetes in the root canal have been investigated only to a minor extent. Oral spirochetes have been detected particularly in the periodontal pocket, where small, medium‐sized and large morphotypes have been reported. In the present parkfield and scanning electron microscopic study we describe a spirochete isolated from the root canal that is 7 times longer (140 μm long) and 5 times thicker (2 μm thick) than usual for treponemes.
In vitro antimicrobial susceptibility of Porphyromonas gingivalis to azithromycin, a novel macrolide
Authors: Pajukanta R.
Published: December 2007

The in vitro antimicrobial susceptibility of Porphyromonas gingivalis to azithromycin, a new macrolide antibiotic of a new class known as azalides, was investigated by the agar dilution method on Brucella agar. Eighty‐two P. gingivalis strains, 79 recent oral isolates, 1 nonoral isolate and 2 reference strains were included in the study. Azithromycin was highly effective against P. gingivalis. All strains were inhibited at 1.0 μg/ml of azithromycin or less. The minimal inhibitory concentrations were 0.25 μg/ml for 50% and 0.5 μg/ml for 90%. These in vitro data as well as the favorable pharmacokinetics of azithromycin indicate that this new oral macrolide might be a good candidate for future clinical trials aiming to eradicate P. gingivalis from refractory periodontitis.
Evaluating two methods for fingerprinting genomes of Actinobacillus actinomycetemcomitans
Authors: Slots J. , Liu Y. B. , DiRienzo J. M. , Chen C.
Published: December 2007

The arbitrary primer polymerase chain reaction (AP‐PCR) and Southern blot restriction fragment length polymorphism (RFLP) were used to genotype the periodontal pathogen A. actinomycetemcomitans. Total genomic DNA from 73 strains was extracted by conventional methods. Three random‐sequence 10‐base oligonucleotide primers were chosen for AP‐PCR. The amplified DNA products were separated electrophoretically in a 1% agarose gel containing ethidium bromide and the banding patterns were compared among different strains. For RFLP analysis, DNA was digested with Eco RI, separated on a 0.8% agarose gel and transferred to a nylon membrane. The membrane was probed with a previously characterized 5.2 kilobases (kb) DNA fragment cloned from A. actinomycetemcomitans strain Y4. The probe was labeled with digoxigenin, and hybridized fragments were detected with anti‐digoxigenin antibody. AP‐PCR produced 4–10 DNA bands in the 0.5–5 kb regions and distinguished 9, 13 or 17 genotypes, depending on the specific primer used. Southern blot RFLP analysis revealed 12 hybridization patterns consisting of 1 or 2 DNA fragments (2–23 kb). The addition of the Southern blot analysis to the AP‐PCR analysis gave rise to a total of 30 DNA profiles among the 73 A. actinomycetemcomitans study strains. The results indicate that both AP‐PCR and Southern blot analysis are useful in clonal analysis of A. actinomycetemcomitans.
The binding of delmopinol and chlorhexidine to Streptococcus mutans and Actinobacillus actinomycetemcomitans strains with varying degrees of surface hydrophobicity
Authors: Freitas L. B. , Rundegren J. , Arnebrant T.
Published: December 2007

This study evaluated the binding of chlorhexidine and the new surface‐active anti‐plaque agent delmopinol hydrochloride to Streptococcus mutans and Actinobacillus actinomycetemcomitans cells with various cell surface hydrophobicities. The influence of saliva concentration on the binding of these compounds was also investigated. The radiolabeled compounds were incubated with bacteria and the cells were recovered using a centrifugal filtering technique. Delmopinol had higher binding to the hydrophilic variant strains than to the hydrophobic parent strains; chlorhexidine had higher binding to hydrophobic than to hydrophilic A. actinomycetemcomitans strains and higher binding to hydrophilic than to hydrophobic S. mutans strains. The presence of salivary films decreased the binding of both compounds. Both delmopinol and chlorhexidine had stronger affinity to A. actinomycetemcomitans cells than to S. mutans cells. At equimolar concentrations, delmopinol had a lower binding to all strains tested than chlorhexidine. The high reversibility of the delmopinol binding might be related to a higher diffusion rate and solubility compared with that of chlorhexidine. The amphiphilicity of both molecules is an important feature in their retention to S. mutans and A. actinomycetemcomitans strains of varying hydrophobicities and could play an important role in the substantivity of delmopinol or chlorhexidine in the oral cavity.
Multivariate chemosystematics demonstrate two groups of Actinobacillus actinomycetemcomitans strains
Authors: Brondz I. , Olsen I.
Published: December 2007

Chemical analysis by us has indicated that Actinobacillus actinomycetemcomitany is not a homogeneous species. The present study used chemometric methods and a multitude of chemical characters to examine this further. Strains were characterized by cell sugar and fatty acid contents, lysis kinetics during EDTA and EDTA plus lysozyme exposure, methylene blue reduction, and API ZYM enzymatic assessment of whole cells and outer membrane vesicles/fragments. In total, 41 quantitative variables were analyzed from each of 9 strains and treated with principal component analysis and soft independent modeling of class analogy. These methods divided A. actimomcetemcomitans into 2 strain groups. One group contained ATCC 33384T, ATCC 29522. FDC 2112 and FDC 2043; the other comprised ATCC 29524, ATCC 29523, FDC 2097. FDC 511 and FDC Y4. With an F‐test, the groups (classes) of A. uctinomycetemcomitans strains could be distinguished at 95% confidence limits. Both groups were distinct from members of the genera Haemophilus and Pasteuclld allaemophilus aphrophilus, Haemophilius parcaphroplus. Haemophilus infhienzae, Pasteurella multocida and Pasteurella haemolytica).
Analysis of the genetic control of antibody response to Actinobacillus actinomycetemcomitans by immunoblotting in inbred strains of mice
Authors: Nitta H. , Ishikawa I.
Published: December 2007

Genetic regulation of the immune response may be involved in the onset and progression of an early‐onset type of periodontitis. We analyzed the genetic control of the primary antibody response to Actinobacillus actinomycetemcomitans in inbred strains of mice using an immunoblot technique. Mice of 5 independent inbred strains, 6 H‐2 congenic strains and 4 B10 intra‐H‐2 recombinant strains were immunized with sonicated extracts of A. actinomycelemcomitans. On the seventh day their sera were examined for reactivity to the antigenic components of this organism. Western blot analysis clearly distinguished 2 different groups of antigens, one consisting of common antigens (molecular weights, 28, 34, 36 and 40 kDa) that reacted with sera from all strains and one consisting of specific antigens (molecular weights 31, 65 and 69 kDa) that reacted only with sera from distinct strains. Blot analysis of sera from H‐2 congenic strains demonstrated that the reactivity to the second group of antigens was regulated by the H‐2 complex. In B10 intra‐H‐2 recombinant strains, only the 1‐Ab allotype strains produced immunoglobulin G antibody that reacted to the 65 kDa antigen. This evidence indicates that the primary immune response to the A. actinomycetemcomitans antigen with a molecular weight of 65 kDa is controlled by genes in the 1‐A subregion of the H‐2 complex. This 65 kDa antigen was also highly reactive with some human sera from early‐onset periodontitis patients. Further analysis of this antigen is required.
Serum immunoglobulin G antibodies to Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum and Streptococcus sanguis during experimental gingivitis in young adults
Authors: Danielsen B. , Wilton J. M. A. , Baelum V. , Johnson N. W. , Fejerskov O.
Published: December 2007

Twenty‐eight young, healthy adults completed an experimental gingivitis study in which blood and clinical recordings were obtained at baseline; after a 4‐week period of thorough oral hygiene; after a subsequent 3‐week period of plaque accumulation; and after another 2 weeks of thorough oral hygiene. Serum immunoglobulin G antibodies against whole cells of Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum and Streptococcus sanguis were determined using enzyme‐linked immunosorbent assay. Mean serum immunoglobulin G antibody levels to P. intermedia, F. nucleatum and S. sanguis remained essentially constant during the experiment, whereas the immunoglobulin G antibodies to P. gingivalis declined during the initial period of oral hygiene and the subsequent period of plaque accumulation to an average of 84.5% of the baseline value. This reduction could be attributed to the people who developed marked gingival inflammation during the period of plaque accumulation, indicating that the systemic host response may be associated with local tissue responses to variations in oral hygiene. These people were, however, also characterized by higher initial serum immunoglobulin G responses to P. gingivalis than people who developed less pronounced gingival inflammation during the experiment. The variability and individuality noted in the host response to potential pathogens have important implications for attempts to use such measures for establishing a diagnosis or prognosis for the individual patient.
In vitro antimicrobial susceptibility to combinations of drugs of bacteria from carious and endodontic lesions of human deciduous teeth
Authors: Sato T. , Hoshino E. , Uematsu H. , Noda T.
Published: December 2007

The purpose of this study was to clarify the antibacterial efficacy of mixed antibacterial drugs on bacteria of carious and endodontic lesions of human deciduous teeth in vitro. The antibacterial drugs used in this study were mixtures of ciprofloxacin, metronidazole, plus a third antibiotic: amoxicillin, cefaclor, cefroxadine, fosfomycin or rokitamycin. Samples taken from carious dentin (17 cases) and infected pulpal tissues (14 cases) were cultured on control plates and plates containing the mixed drugs. No bacteria were recovered in the presence of any combination of the mixture of the drugs (100μg each/ml), and the bacterial growth occurred on control plates (101 to 107 colony‐forming units), indicating that the mixed drugs inhibit the growth of bacteria in the samples. When carious and endodontic lesions on split surfaces of freshly extracted teeth were covered overnight with α‐tricalcium phosphate cement containing a mixture of ciprofloxacin, metronidazole and cefaclor (1% each; 5 cases), no bacteria were recovered from the lesions. No bacteria were recovered from carious and endodontic lesions when these lesions were immersed in a solution of the mixture (200 μg each/ml; 5 cases). These findings indicate that carious and endodontic lesions can be sterilized by the mixed drugs in situ.
Effect of antibody in gingival crevicular fluid on early colonization of exposed root surfaces by mutans streptococci
Authors: Smith D. J. , van Houte J. , Kent R. , Taubman M. A.
Published: December 2007

The effect of antibody to Streptococcus mutans in gingival crevicular fluid (GCF) on the recolonization of cleaned buccal root surface sites by indigenous mutans streptococci was studied. Seven subjects (mean age = 64 years) were selected from a population of 28 on the basis of the presence of appropriate sites with and without detectable immunoglobulin G (IgG) antibody in GCF to formalin‐killed S. mutans and adequate levels of mutans streptococci in saliva available for root surface recolonization. Root surfaces exposed to GCF that did or did not contain antibody were then cleaned and sampled for residual plaque organisms (total cultivable flora and mutans streptococci) directly after cleaning (time 0) as well as 24 h later. One subject failed to recolonize at 24 h at any (antibody‐positive or antibody‐negative) experimental site. For each of the remaining 6 subjects, the mean levels of mutans streptococci (mean percentage of total flora) were lower at sites with IgG antibody to S. mutans in GCF than at antibody‐negative sites in the same subject. In each of the 6 subjects, the site with the highest recolonization level was antibody‐negative. Comparison based on intra‐subject randomization of sites suggested diminished recolonization of mutans streptococci at sites with antibody 24 h after cleaning. The results support the idea that antibody in GCF can modify the early colonization of gingival root surface areas by potentially cariogenic plaque bacteria such as mutans streptococci.
In vitro activation of the classical pathway of complement by a streptococcal lipoteichoic acid
Authors: Monefeldt K. , Helgoland K. , Tollefsen T.
Published: December 2007

The purpose of this study was to find whether a glycerolphosphate‐containing lipoteichoic acid prepared from Streptococcus suhrinus OMZ 176 cells would activate the classical pathway of complement while in solution. Reference activators were lipopolysaccharide from Escherichia coli 0111:B4 and heat‐aggregated immunoglobulin G. Serum samples were taken from healthy students. Analysis through crossed immunoelectrophoresis showed that lipoteichoic acid caused an almost complete dissociation of the Clqrs macromolecule. All activators decreased the area of and slowed the electrophoretic mobility of the C4 protein peaks, with lipoteichoic acid causing the most pronounced alterations. Electroimmunoassays showed that lipoteichoic acid separately, yielded detectable amounts of free Clr2s2 subunits; it also generated significantly more trimer complexes between Clr, CIs and Cl inhibitor (CIINH) than did the other two activators. Lipoteichoic acid was, however, a comparatively weak inducer of telramer ClINH‐Clr‐Cls‐ClINH complexes. Analysis through Western blotting showed that all activators accelerated consumption of Clr, induced complex formations between CIINH and CIs and produced cleavage products of C2. Altogether, the immunochemical analysis gave clear evidence of classical pathway activation by lipoleichoic acid, but its activation profile differed form those seen with lipopolysaccharide and aggregated immunoglobulin G.
Oxygen‐dependent modulation of release and activity of polymorphonuclear leukocyte granule products
Authors: Claesson R. , Johansson E. , Carlsson J.
Published: December 2007

Polymorphonuclear leukocytes are important in the defense against the anaerobic microflora of infected gingival pockets. One part of this defense is release of antibacterial granule products by polymorphonuclear leukocytes into the pockets. The aim of the present study was to compare the efficiency of polymorphonuclear leukocytes in releasing granule products under aerobic and anaerobic conditions. Polymorphonuclear leukocytes were exposed to serum‐opsonized zymosan under aerobic and anaerobic conditions. The levels of released granule products were determined by combining measurements of activity with enzyme‐linked immunosorbent assays. The level of released elaslase was twice as high in anaerobic as in aerobic reaction mixtures. A similar difference was not detected for mycloperoxidase. However, mycloperoxidase was inactivated after its release under aerobic conditions. The release of lactoferrin was as efficient under aerobic as under anaerobic conditions. The effect of aerobic conditions on the release of elastase and the inactivation of myeloperoxidase could be ascribed to oxidants formed in the mycloperoxidase‐H2O2‐chloride system. Also, the activity of the released cytoplasmic enzyme lactate dehydrogenase was inactivated by oxidants formed in the myeloperoxidase‐H2O2‐chloride system. These findings suggest that, in the anaerobic environment of the gingival pocket, elastase and possibly also other azurophilic granule products are released in higher amounts than under fully oxygenated conditions. In this environment, the released products may also escape inaclivation by the myeloperoxidase‐ H2O2‐chloride system.
Changes in root canal microbiota during the development of rat periapical lesions
Authors: Tani‐Ishii N. , Wang C.‐Y. , Tanner A. , Stashenko P.
Published: December 2007

Periapical lesions are reproducibly induced in rats by pulp exposure and infection from the oral cavity. Lesions expand rapidly between day 7 and day 15‐20 (active phase), with slowed expansion thereafter. In the present study we characterized the root canal microbiota present during the active phase of lesion development in this system. The mandibular first molars of Sprague‐Dawley rats were exposed on day 0. The teeth were extracted after 7 days (n= 10 animals) and 15 days (n= 10), and the microbiota present in roots was isolated and characterized. The number of colonies isolated per tooth was similar on day 7 (1.53 ± 0.64 colony‐forming units × 103) and day 15 (1.49 ± 0.37 colony‐forming units × 103). No colonies were isolated from unexposed control teeth. Anaerobic bacteria increased significantly between day 7 (24.3 ± 5.7%) and day 15 (47.3 ± 7.5%), and the proportion of gram‐negative organisms increased from day 7 (24.3 ± 6.1) to day 15 (46.9 ± 6.8). The predominant bacteria included, on day 7: Streptococcus and Bacteroides species; on day 15: species of Streptococcus, Bacieroides, Prevotclla, Neisseria and Peptostreptococcus. Streptococcus oralis, Streptococcus mitis, Streptococcus rattus, Bacteroides pneumosinles and Bacteroides ureolyticus were frequently isolated at both points. Although approximately the same mean number of different species (∼3.5) was isolated per tooth on both day 7 and 15, the overall diversity of the isolates increased on day 15. These results demonstrate that the root canal microbiota becomes increasingly gram‐negative and anaerobic with the emergence of Peptostreptococcus, Bacteroides, Prevotella and Neisseria during the period of rapid lesion expansion in this model.
Oral immunization of humans with dehydrated liposomes containing Streptococcus mutans glucosyltransferase induces salivary immunoglobulin A2 antibody responses
Authors: Childers N. K. , Zhang S. S. , Michalek S. M.
Published: December 2007

Seven healthy adult volunteers each ingested an enteric‐coated capsule containing 500 fig of Streptococcus mutans glucosyltransferase (GTF) in dehydrated liposomes for 3 consecutive days. The immunization regimen was repeated 28 days later. Parotid saliva and plasma were collected prior to and at a weekly interval for 8 weeks following the first immunization for analysis of anti‐GTF activity by enzyme‐linked immunosorbent assay. The levels of immunoglobulin A, (IgA), and IgA: anti‐GTF activities increased in the parotid saliva from 5 of 7 individuals after immunization. Increases in the mean level of IgA, and lgA: anti‐GTF responses peaked on day 35 (77% and 175% increase over baseline, respectively), although variation was noted in the kinetics and subclass of responses between individuals. No salivary IgG or IgM responses were observed. Low plasma IgM, IgG and IgA anti‐GTF responses were seen in immunized subjects. Oral immunization with a dehydrated liposome‐protein vaccine was effective in inducing a secretory IgA antibody response, which was primarily of the IgA: subclass. These results provide the first evidence for the use an oral dehydrated liposome‐protein vaccine in humans.
Evidence for an ecto‐ATPase on the cell wall of Streptococcus sanguis
Authors: MacFarlane G. D. , Sampson D. E. , Clawson D. J. , Clawson C. C. , Kelly K. L. , Herzberg M. C.
Published: December 2007

Certain strains of viridans streptococci bind platelets, which release ATP from dense granules and then aggregate. By hydrolyzing the released ATP to the platelet agonist, ADP, cell wall‐associated ATPase activity of Streptococcus sanguis may amplify the aggregation of platelets. To identify and characterize this ecto‐ATPase activity, whole cells were incubated with [14C]‐ATP. The cell‐free nucleotides were separated by thin‐layer chromatography and quantified by liquid scintillation counting. Whole‐cell activity showed temperature and pH optima in the physiological range. To isolate a soluble fraction with ATPase activity from the cell wall, whole cells were digested under osmotically stable conditions to produce protoplasts. Protoplasts and cells were separated from soluble cell wall materials by centrifugation. ATPase activity in cell fractions was identified by zymograms of native 8% polycrylamide gels after electrophoresis. The ecto‐ATPase preparation, membrane and cytoplasmic ATPase in lysed protoplasts showed different zymograms and sensitivity to inhibition by DCCD, ouabain vanadate, azide and NEM. In electron micrographs of ultrathin sections of cells of S. sanguis, ATPase activity was localized to the cell wall. Since the pattern of localization to the wall changed with the phase of growth, the ecto‐ATPase of S. sanguis may be associated with the development and maintenance of the cell wall.
Biochemical change exhibited by oral streptococci resulting from laboratory subculturing
Authors: Cvitkovitch D. G. , Hamilton I. R.
Published: December 2007

The intent of this study was to assess the effects of continued laboratory subculturing on selected biochemical properties of oral streptococci freshly isolated from dental plaque. Six fresh isolates (3Streptococcus mutansand 3 non‐mutans) and 2 laboratory strains were subcultured daily for a total of 225 transfers, and cells were harvested every 75 transfers from duplicate batch cultures grown with glucose at a constant pH. Eleven biochemical properties were assayed with cells, membranes and cell‐free extracts and the results subjected to statistical analysis for differences between the duplicate cultures and the various subcultures. In addition, the activity of 19 hydrolytic enzymes was assayed with the semiquantitative apiZYM® system (Analytab products). The activity of zero‐time samples varied by as much as 241‐fold for a single property with particularly low activity for EIIglcof the phosphoenolpyruvate phosphotransferase system and cell‐associated extracellular polysaccharide synthesis. The 3S. mutansfresh isolates had higher activity in 8 of the 11 assays compared with the 3 non‐mutans strains, with extracellular polysaccharide synthesis the most significant trait. Statistical analysis of the 2816 assays of the 11 traits for the 8 test strains at the 4 selected time intervals revealed considerable change in the activity of the test parameters. The most notable changes in theS. mutansstrains over the 225 subcultures were significant increases in glycolytic activity and decreases in hydrophobicity and extracellular polysaccharide synthesis activity. Of the measured properties, lactate dehydrogenase and cell‐associated extracellular polysaccharide synthesis activity were the most stable and H+/ATPase activity was the most variable. The apiZYM® analysis revealed that of the 88 active tests, 41% showed no change in activity, 17% increased, 20% showed variation and 22% decreased or showed a complete loss of activity. These results indicate that continued laboratory subculturing of oral streptococci results in the selection of strains that possess different properties than those growingin vivoin dental plaque.
The effect of indigenous bacterial populations on buccal epithelial cells on subsequent microbial adhesion in vitro
Authors: Samaranayake L. P. , Hamilton D. , MacFarlane T. W.
Published: December 2007

Despite the numerous investigations on the adhesion of microorganisms to buccal epithelial cells, it is difficult to correlate different results, as disparate adherence values have been reported for a given organism. As one reason for this disparity may be the indigenous or natural bacterial populations on human buccal epithelial cells, the effect of the latter on subsequent microbial adherence in vitro was examined. There was a highly significant correlation between the degree of natural bacterial colonization on pooled buccal epithelial cells from 8 healthy donors and the adhesion of a single isolate each of Streptococcus mitis, Escherichia coli and Actinomyces naeslundii. However, no such relationship could be established for Candida albicans. Streptococcus milleri and another isolate of Streptococcus mitis. As in previous studies, variation in adherence values was found, both between samples from different donors, and from the same donor over time, but to a far lesser degree in pooled samples from different donors. These results imply that natural bacterial populations on buccal epithelial cells may affect the adhesion values derived from laboratory experimentation, and hence such data should be interpreted with caution.
Host‐related genotypic heterogeneity of Porphyromonas gingivalis strains in the beagle dog
Authors: Madianos P. N. , Papapanou P. N. , Socransky S. S. , Dahlén G. , Sandros J.
Published: December 2007

The present investigation explored the genotypic heterogeneity of Porphyromonas gingivalis using restriction endonuclease analysis and ribotyping of 64 P. gingivalis isolates, recovered from the periodontal pockets of 3 beagle dogs, 2 of which were reared together. The isolates originated from both healthy and periodontal disease affected sites and thereby enabled the study of bacterial genotype with respect to (i) individual host, (ii) ecological niche (site within host) and (iii) level of periodontal health. Whole genomic DNA was extracted from each isolate and digested by the restriction endonuclease KpnI. Digestion fragments were separated by electrophoresis and transferred onto nylon membranes. The blots were hybridized with a digoxigenin‐labeled 16S rDNA probe, and hybridization bands were detected using an anti‐digoxigenin antibody conjugated with alkaline phosphatase and enhanced chemiluminescence. Fourteen genomic fingerprints and 13 ribotypes were observed among the 64 isolates. As many as 8 distinct fingerprints were detected within a single host and up to 4 fingerprints within a single periodontal pocket. The dogs reared together shared 2 common clonal types but also exhibited clonal types unique to each dog. No clear association between clonal type and periodontal health status could be made. The results revealed an extensive intra‐host genotypic heterogeneity of P. gingivalis strains in the beagle dog and indicated that ribotyping was a sensitive method for differentiating clonal types within species.
Immunoglobulin A antibodies to mutans streptococci in human saliva and serum comparing fresh and subcultivated strains and activity in repeated saliva samples
Authors: Widerström L. , Bratthall D. , Hamberg K.
Published: December 2007

The aims of this study were i) to characterize and compare the sodium dodecyl sulfate‐polyacrylamide gel electrophoresis protein patterns of reference Streptococcus mutans and Streptococcus sobrinus strains, subcultivated for years, with fresh isolates of the same serotype; ii) to study possible differences between the human salivary immunoglobulin A (IgA) activity to reference strains and to fresh bacterial isolates of the saliva donors; iii) to examine for potential differences in the salivary IgA activity to the streptococcal antigens during 1 week; and iv) to map, in the same individuals, the serum IgA activity against the selected bacteria. S. mutans reference and fresh isolated strains showed a similar protein pattern with few exceptions. The immunoblot also revealed similarity in saliva IgA response, with only one subject's saliva displaying clearly one band's difference. For S. sobrinus a larger discrepancy was seen. The antibody activity during the one week interval was essentially unchanged. When incubated with serum, a different immunoblot profile was seen compared with saliva, although most bands revealed by saliva were also displayed by serum.
Adoptive transfer of cloned T helper cells ameliorates periodontal disease in nude rats
Authors: Eastcott J. W. , Yamashita K. , Taubman M. A. , Harada Y. , Smith D. J.
Published: December 2007

We have previously described a T helper cell 2‐type clone, A3, of rat T cells that provides help for antibody production to Actinobacillus actinomycetemcomitans in vitro and in vivo in normal (euthymic) isogeneic Rowett strain recipient rats. Adoptive transfer of this T helper cell clone to euthymic rats also protects them from periodontal bone loss induced by oral infection with A. actinomycetemcomitans. In the present study, to assess the cell requirement for protection, A3 clone T lymphocytes (106) or naive lymph node (6 × 104) T cells, or A3 plus naive lymph node T cells (6 × 104) were adoptively transferred to groups (n= 7–9) of 30‐day‐old Rowett athymic nude (rnu/rnu) rats. All recipients were also immunized (intraperitoneally) with 107 killed A. actinomycetemcomitans on the day of T cell transfer and orally infected with these bacteria on each of the next 5 days. Recipients of the combined A3 + lymph node T cell transfer showed significantly increased serum immunoglobulin G (IgG) and IgM antibody to A. actinomycetemcomitans and in vitro proliferation of spleen lymphocytes to A. actinomycetemcomitans as antigen compared with nude animals receiving lymph node T cells only. Although other possibilities are discussed, we inferred that these differences might be due to successful population of the congenitally athymic rats by A3 clone cells given with a small number of normal autologous naive lymph node T cells. The result of this co‐transfer of naive T cells with the A3 clone cells seemed to be greatly increased antibody production and protection from periodontal bone loss.
Homology among Treponema denticola plasmids
Authors: Reedy E. , Simonson L. , Zablen L.
Published: December 2007

Three of 16 isolates of Treponema denticola were found to contain small (2.0–2.7 kb) cryptic plasmids. These were pTD1 from T. denticola ATCC 33520, pTD2 from strain T32A, and pTD3 from strain D3A1. These plasmids were characterized by restriction mapping and cloned into E. coli plasmid pUC19. Extensive homology between these plasmids was revealed by Southern blot, and single‐stranded DNA regions were found by neutral Southern blots and S1 nuclease mapping. These plasmids were not found in serovars usually associated with human periodontal disease nor are they universal in all T. denticola strains and serovars.
Surface‐associated properties of Actinomyces strains and their potential relation to pathogenesis
Authors: Loo C. Y. , Willcox M. D. P. , Knox K. W.
Published: December 2007

Twenty‐nine strains from the Actinomyces species were tested for a range of surface properties. Results show considerable heterogeneity both between different species and within some of the species, especially Actinomyces naeslundii. Two commonly used A. naeslundii strains, T14V and ATCC 12104, fell within the low (salivary aggregation and collagen binding by T14V). moderate (surface charge and haemagglutination) or high range of values (hydrophobicity, saliva‐coated hydroxyapatite adhesion, polystyrene binding by T14V, fibrinogen binding by T14V and collagen binding by A. naeslundii ATCC 12104). Both strains adhered well to saliva‐coated hydroxyapatite; TI4V bound the highest amount of fibrinogen, ATCC 12104 had the highest number of cells bound to collagen and T14V was not bound at all. The heterogeneity of these characteristics highlights the need to include a range of strains of Actinomyces in studies on their pathogenicity. Statistical correlations were found between a number of properties, for example saliva‐coated hydroxyapatite adhesion and hydrophobicity, and between haemagglutination and hydrophobicity.
The effects of human immunodeficiency virus infection on macrophage phagocytosis of Candida
Authors: Eversole L. R. , Fleischmann J. , Baldwin G. C. , Sapp J. P.
Published: December 2007

The effects of infection by human immunodeficiency virus (HIV) on phagocytic function towards Candida pseudotropicalis were tested using monocytotropic and nonmonocytotropic HIV strains on peripheral blood monocytes. There were no differences in either quantitative phagocytic activity or efficacy between the two infected and control mock‐infected monocytes. Immunofluorescence for cytoplasmic p24 antigen and in situ hybridization for detection of HIV‐specific RNA sequences revealed that very few cells (10−4) exhibit productive infection. Occasional cells with active infection as defined by microscopically detectable fluorescence labelling contained phagocytized yeasts.
Gingival Crivicular fluid antibody to Actinobacillus actinomycetemcomitans in periodontal disease
Authors: Ebersole J. L. , Cappelli D.
Published: December 2007

We identified antibody isotypes and subclass proportions in gingival crevicular fluid to understand the potential protective ability of these antibodies towards infection with Actinobacillus actinomycetemcomitans. Immunoglobulin G (IgG) 1–4 antibody levels to A. actinomycetemcomitans serotype b were quantified in serum and‐gingival crevicular fluid from 20 periodontitis patients who had at least one subgingival plaque sample with cultivable A. actinomycetemcomitans. The subclass antibody levels in the patients' sera were IgG1 = IgG2)IgG3)IgG4. A portion of the gingival crevicular fluid samples had IgG (15.7%; range: 0–52%) and IgA (2.5%; range: 0–15%) antibody that was significantly elevated compared with serum. Gingival crevicular fluid samples with elevated IgG antibody were analyzed for the subclass distribution and showed elevated IgG3 (58%), IgG4 (35%), IgGl (25%) and IgG2 (25%) antibody in the gingival crevicular fluid. These results demonstrated a characteristic distribution of both serum and gingival crevicular fluid IgG subclass responses to A. actinomycetemcomitans. We also examined the sites with elevated antibody in each subclass for the presence of A. actinomycetemcomitans in the subgingival microbiota. The results showed that >95% of sites with elevated IgG4 were colonized, whereas (50% of sites with elevated IgG2 demonstrated this microorganism. IgG2 and IgG4 levels were primarily elevated in diseased sites, whereas IgG4 elevations were absent in healthy sites. The frequency and distribution of antibody in the gingival crevicular fluid as related to colonization with this microorganism were consistent with localized host‐parasite interactions at individual tooth sites. The relative subclass distribution of elevated gingival crevicular fluid antibody was shown to be IgG3)Ig‐G4)IgG2 = IgG1. These antibody types suggest that the potential exists for this local antibody to A. actinomycetemcomitans to play an important role in the gingival sulcus in relationship to colonization and clinical presentation.
Distribution and characterization of plasmids in oral anaerobic spirochetes
Authors: Caudry S. , Klitorinos A. , Gharbia S. E. , Pssara N. , Siboo R. , Keng T. , Chan E. C. S.
Published: December 2007

Fifteen oral spirochete strains belonging to the species Treponema denticola, Treponema vencentii and Treponema socranskii as well as 9 fresh clinical isolates were screened for the presence of extrachromosomal plasmid DNA by a modified alkaline lysis procedure. A 2.6–kb plasmid was detected in both T. denticola ATCC 33520 and T. denticola e'. The 2.6–kb plasmid from T. denticola e' was shown to be similar to pTDl, previously reported by Ivic et al. in T. denticola ATCC 33520 on the basis of molecular weight, restriction endonuclease profile and DNA:DNA hybridization. T. denticola ATCC 33520 and T. denticola e'share 65% DNA homology and belong to different serological groups. This dissimilarity has been reconfirmed by specific immunofluorescence using polyclonal and monoclonal antibodies. A plasmid‐free T. denticola ATCC 33520 was identified. Comparative studies have shown no antigenic, morphological, or genetic differences between the plasmid‐bearing and the plasmid‐free strain. In addition, screening of fresh clinical isolates of spirochetes revealed the presence of a 4.2–kb plasmid in 4 of these strains.
Detection of human papillomavirus in oral lesions using commercially developed typing kits
Authors: Dhariwal S. K. , Cubie H. A. , Southam J. C.
Published: December 2007

Biopsy material from 20 oral lesions (19 condylomas and 1 squamous papilloma) previously shown to contain human papillomavirus (HPV) 6 and HPV 11 sequences by in situ hybridization were examined using 3 commercially available HPV typing kits. Sensitivity and specificity were compared with in‐house methods. Previous in situ hybridization had detected HPV 6b in 11 (55%) of the biopsies, HPV 6 and 11 in 7 (53%) and HPV 11 alone in 1 biopsy. Only one of the commercial assays (assay 1) detected HPV in all 20 biopsies (11 positive for HPV 6b only, 1 for HPV 11 only and 7 for HPV 6b and 11). The wide spectrum probe of assay 2 detected HPV in only 10 (50%) of the biopsies, and in a further 2 biopsies the hybridization results were difficult to interpret because of background staining. Assay 3 used a combined HPV 6/11 probe and detected HPV in 15 (75%) of the biopsies. Clear hybridization signals were demonstrated in the intermediate and upper layers only of squamous epithelium, as expected from the known association of HPV replication with epithelium differentiation. In most specimens background levels were not a problem, and all commercial assays were easy to use. The findings are discussed in the context of the digestion procedures, sensitivity of the probes provided and the conditions of hybridization, all of which would influence the detection of HPV
The effects of transforming growth factor‐ and interleukins 2,5 and 6 on immunoglobulin production in cultured rat salivary gland tissues
Authors: Rafferty D. E. , Montgomery P. C.
Published: December 2007

The effects of transforming growth factor‐β, alone, and in combination with selected interleukins on immunoglobulin production were investigated using an in vitro rat tissue fragment culture system with either parotid, submandibular or sublingual gland tissue. In the majority of culture groups, TGF‐β alone, or in combination with either interleukin 2 (IL‐2), IL‐5, IL‐6 or IL‐5 and IL‐6 together, significantly increased immunoglobulin A (IgA) levels over those obtained in untreated cultures. The levels of IgG and IgM were generally not affected, with the exception of one sublingual and two submandibular groups(s), where cytokine administration up‐regulated either IgG or IgM production. These data indicate that transforming growth factor‐β in combination with IL‐2, IL‐5, IL‐6 or IL‐5 and IL‐6 can exert a stimulatory effect on IgA production in vitro, supporting a potential regulatory role for these cytokines in salivary gland IgA responses.
Microbial generation time during the early phases of supragingival dental plaque formation
Authors: Weiger R. , Netuschil L. , von Ohle C. , Schlagenhauf U. , Brecx M.
Published: December 2007

Weiger R, Netuschil L, von Ohle C, Schlagenhauf U, Brecx M. Microbial generation time during the early phases of supragingival dental plaque formation.

The objective of this investigation was to determine the microbial generation time during early human supragingival plaque formation. On 2 occasions, 13 participants refrained from all oral hygiene measures for periods of 1, 2, 4, 8, 24 and 72 h. Plaque was sampled from defined areas of the teeth 13, 14, 15, 23, 24 and 25. Two independent methods were used to estimate the total number of viable cells: colony‐forming units BCVFtotal bacterial counts (BC) as enumerated by microscopic examination, and the percentage of vital bacteria using a vital fluorescence technique (VF) were recorded. The total number of vital microorganisms was calculated by BCVF (= BCxVF). The generation time based on either colony‐forming units or BCVF increased significantly with plaque age. During the first interval (1‐4 h), the microbial multiplication took slightly less than 1 h. After the establishment of a more mature plaque (24‐72 h), the replicating time was between 12.5 h (BCVF) and 14.8 h (colony‐forming units). It was concluded that the microbial generation time recorded at the initial stages of plaque formation is considerably lower than that found in older plaque.
Patterns and rates of growth of microcosm dental plaque biofilms
Authors: Sissons C. H. , Wong L. , Cutress T. W.
Published: December 2007

Rates of growth in wet weight and changes in them over time were established for microcosm dental plaques cultured from the mixed salivary bacteria in an artificial mouth. Standardized conditions included a continuous supply of medium containing 0.25% mucin and 1.5 ml of 5% w/v sucrose in 6 min every 8 h. Plaques were weighed daily. Plaque wet weight and total protein were highly correlated. Plaque doubling times were 3‐7 h over day 1 and 9‐21 h over day 2, which is similar to in vivo plaques. Subsequently, growth curves were either linear or between a linear and exponential increase. Evidence was obtained for plaque blooms. Methyl paraben (0.2%) applied for 15 min (3.75 ml) 6 times daily inhibited growth but only for 3 days, after which the rate was similar to control plaques, indicating that selection for resistance had occurred. It was concluded that the regulation of plaque growth rates is complex and does not conform to simple growth pattern models. Detailed studies of plaque growth and the effects of antiplaque agents can be carried out using this experimental system.