bluuebunny/crossref_metadata_2025 huggingface dataset:
Microbial vitality of supragingival dental plaque during initial stages of experimental gingivitis in humans
Authors: Weiger R. , Netuschil L. , von Ohle C. , Brecx M.
Published: July 2006

Although vital plaque micro‐organisms are part of the natural ecosystem in the oral cavity they are also the key factor in the development of diseases induced by the human dental plaque. In a previous study (9) the portion of vital bacteria related to the total number of plaque micro‐organisms (i.e. the microbial vitality) appeared low in small plaque samples. The objective of this investigation was to determine the exact relationship of microbial vitality and age of supragingival plaque during the early phases of human dental plaque formation. Between intervals of optimal oral hygiene, thirteen participants refrained from all oral hygiene measures for periods of 1, 2, 4, 8, 24 and 72 h. Plaque was completely sampled from a defined area situated on the vestibular surface of the teeth 13, 14, 15, 23, 24 and 25. The pooled plaque from these areas was immediately processed. Total bacterial counts (BC) as enumerated by darkfield microscopy, and colony‐forming units (CFU) were recorded. The microbial vitality was calculated indirectly as plating efficiency (PE=CFU per BC) and directly assessed using a vital fluorescence (VF) technique. In the 1 h old plaque samples the median values of PE and VF were 29% and 18%, respectively. Thereafter, the microbial vitality increased significantly with plaque age. The 24 h old plaque samples yielded values of 77% (PE) and 62% (VF). It was concluded that the microbial vitality of the early dental plaque investigated was considerably lower compared to that of a more mature plaque.
Development and characterization of an in vitro gingival epithelial model
Authors: Odioso L.L. , Doyle M.J. , Quinn K.W. , Bartel R.L. , Zimber M.P. , Stevens‐Burns D.
Published: July 2006

A 3‐dimensional gingival epithelial model has been developed and characterized. Oral epithelial cells and connective tissue fibroblasts were isolated from human gingival tissue and used to create an in vitro oral mucosa co‐culture model. Fibroblasts were seeded on a scaffold of nylon mesh, allowed to proliferate and secrete collagen and extracellular matrix proteins to form a stroma capable of supporting the growth of epithelial cells. Epithelial cells were seeded on top of a confluent stromal layer, proliferated and differentiated to form a stratified squamous epithelium. Resident epithelial cells were stimulated, by manipulation of growth medium and culture conditions, to form a multi‐layered oral mucosa‐like tissue. Histologic analyses revealed cellular architecture exhibiting stromal‐epithelial interaction which supports the growth and differentiation of an epithelial layer. lmmunohistochemical analyses confirmed production of types I and III collagen. Immunofluorescence of the stromal layer identified type IV collagen and fibronectin. Fibronectin was also detected on surface epithelium. Differentiation of basal, spinous and granular cells was observed, and the presence of differentiation markers, acidic (K10, 14–16, 19) and basic (Kl–8) cytokeratins were confirmed using broad spectrum cytokeratin antibodies, AE1 and AE3. Development of a discontinuous basal lamina zone, with hemidesmosomes, was observed by electron microscopy. The co‐culture was metabolically active, as measured by the thiazoyl blue (MTT) assay for mitchondrial function and [3H] thymidine incorporation into DNA. The human gingival epithelial co‐culture model was viable up to 35 days post‐epithelial seed. This model may offer opportunities for limited study of periodontal tissue responsiveness.
Microflora in adult periodontitis
Authors: Petsios A. , Nakou; M. , Manti F.
Published: July 2006

The subgingival microflora of adult periodontitis was studied in 8 adults (36–47 years) and compared with that of 10 periodontally healthy individuals (36–43 years). A total of 64 periodontal lesions were examined, and classified according to the attachment level in three categories: attachment loss >6 mm, attachment loss 4–6 mm and attachment loss <4 mm. Also for comparative purposes 20 gingival sulci were evaluated. Samples were taken using three standardized paper points and were incubated anaerobically in selective and non‐selective media. The results showed a statistically significant association of Capnocytophaga gingivalis and Capnocytophaga sputigena with moderate periodontal lesions, while Haemophilus segnis has been correlated to severe periodontal lesions. We concluded that C. gingivalis, C. sputigena and H. segnis might be potentially conducive to periodontal deterioration in adult periodontitis.
Distribution of Porphyromonas gingivalis and Treponema denticola in human subgingival plaque at different periodontal pocket depths examined by immunohistochemical methods
Authors: Kigure T. , Saito A. , Seida K. , Yamada S. , Ishihara K. , Okuda K.
Published: July 2006

Localization of Porphyromonas gingivalis and Treponema denticola in different areas of subgingival plaque from advanced adult periodontitis patients was studied immunohistochemically using sensitive immunogold‐silver staining and immunoelectron microscopy. Fourteen periodontally diseased teeth were extracted without damaging the subgingival plaque, fixed, and embedded. The subgingival plaque samples were sectioned according to four different pocket depths (0–2 mm, 2–4 mm, 4–6 mm and ≤6 mm). Serial thin sections were stained using specific antisera to P. gingivalis or T. denticola and then with secondary antibody labelled with colloidal‐gold. Cells of both P. gingivalis and T. denticola were predominantly found in subgingival plaque located at depths of more than 4 mm in periodontal pockets. T. denticola cells were found in the surface layers of subgingival plaque, and P. gingivalis were predominant beneath them. However, in the deeper subgingival plaque, the coexistence of P. gingivalis and T. denticola was observed. The present findings suggest that P. gingivalis and T. denticola play important roles in the pathogenicity of periodontal disease and provide the useful information for elucidating the pattern of colonization of microorganisms in the periodontal pocket.
Immunohistochemical study of linear gingival erythema from HIV‐positive patients
Authors: Gomez R.S. , da Costa J.E. , Loyola A.M. , de Araújo N.S. , de Araújo V.C.
Published: July 2006

Severe forms of periodontal disease are frequent in patients with acquired immunodeficiency syndrome (AIDS). Linear gingival erythema (LGE) is a progressive disease described in HIV‐positive patients and is considered to be an early stage of necrotizing periodontitis. Although clinical and microbiological differences are reported in LGE and non‐specific gingivitis (NSG), a comparative immunopathological approach of both has not been performed yet. The purpose of this study was to compare relative populations of T‐lymphocytes, B‐lymphocytes, neutrophils, macrophages and IgG bearing plasma cells in gingival biopsies from sites exhibiting LGE and from sites exhibiting NSG. A biotin‐streptavidin amplified system was used for identification of the following antigens: CD3 (T‐lymphocytes), CD20 (B‐lymphocytes), elastase (neutrophils), CD68 (macrophages) and IgG (plasma cell's secretors of IgG). The results have demonstrated decrease proportions of T‐lymphocytes, macrophages and high percentage of neutrophils and IgG bearing plasma cells in LGE. In contrast with NSG, many neutrophils cells in LGE were found inside oral gingival epithelium. Our results highlight the idea that progressive periodontal disease is not only characterized by increased tissue inflammation, but, in addition, by significant changes in the proportion of specific inflammatory cells. The high number of neutrophils along the gingival epithelium is probably associated with the severe gingival necrosis reported in AIDS patients.
Specific cementum attachment protein enhances selectively the attachment and migration of periodontal cells to root surfaces
Authors: Pitaru S. , Narayanan S.A. , Olson S. , Savion N. , Hekmati H. , Alt I. , Metzger Z.
Published: July 2006

A specific cementum attachment protein (CAP) was identified in human cementum and found to bind with high affinity to non‐demineralized root surfaces, hydroxyapatite and fibronectin. Attempting to elucidate the biological function of this protein and its possible role in cementogenesis the capacity of CAP to promote selective cell migration towards and attachment of various periodontal derived cell populations to root surfaces in vitro was assessed. Human gingival fibroblasts (HGF), periodontal ligament cells (HPC), and alveolar bone cells (HABC) were labeled with [3H]Thymidine during their exponential growth phase. Root slices, 300 μm thick, were incubated with increasing concentrations of CAR Untreated and fibronectin (FN) treated root slices served as negative and positive controls, respectively. Migration was assessed by placing root slices on confluent layers of labeled cells maintained in serum free medium and determining the number of cells migrated onto the root surface 3 days thereafter. Attachment was assessed by incubating root slices with labeled cell suspensions for 2 h and determining the number of attached cells. CAP promoted both cell migration and attachment dose dependently. HABC responded better than HPC and HGF to CAP treated root slices, and HPC response was higher than that of HGF. Cell attachment was dose dependently inhibited by synthetic RGD pep‐tides. FN did not affect the migration of HGF, barely enhanced that of HABC, and was less potent than CAP at enhancing the migration of HPC. FN was more effective than CAP in promoting the attachment of HGF to root slices, but it was as potent as CAP in supporting the attachment of HPC and HABC. The results indicate that CAP promotes preferential migration towards and attachment to root surfaces of HABC and HPC as compared to HGF and suggests that CAP might be effective in supporting cementogenesis.
Influence of periodontal bacteria and disease status on Vβ expression in T cells
Authors: Mathur A. , Michalowicz B. , Yang C. , Aeppli D.
Published: July 2006

Some bacterial antigens such as S. aureus enterotoxins can selectively stimulate T cells that express specific Vβ genes of the T cell antigen receptor (TCR). The purpose of this study was to investigate whether or not periodontal bacteria could similarly alter the expression of Vβ families within the TCR complex. Peripheral blood mononuclear cells (PBMNCs) were isolated from 12 patients with early onset periodontitis and 11 periodontally‐healthy controls. PBMNCs were incubated in media alone, or co‐cultured for 48 h with heat‐inactivated A. actinomycetemcomitans, P. gingivalis, and P. intermedia. Expression of five Vβ families (Vαβ2, Vβ5, Vβ6, Vβ8, and Vβ12) was determined by use of monoclonal antibodies. Mean unstimulated expression of Vαβ2 and Vβ8 was significantly higher (p<0.05) in patients than healthy controls. Co‐culture with the three bacteria resulted in significant changes (increases or decreases) in Vβ expression in 27% of the trials. There were no significant differences in the number or direction of changes in samples from patients and controls. When compared to unstimulated controls, 18 significant increases but no decreases in the percentage of cell expressing Vαβ2, Vβ5, or Vβ6 were noted following co‐culture with P. intermedia. Overall, co‐culture with P. intermedia significantly (p<0.05) upregulated expression of the five Vβ families studied. These data suggest that periodontal bacteria may alter Vβ expression within the T cell receptor complex.
Synthesis of proinflammatory cytokines by human gingival fibroblasts in response to lipopolysaccharides and interleukin‐1β
Authors: Agarwal S. , Baran C. , Piesco N.P. , Quintero J.C. , Langkamp H.H. , Johns L.P. , Chandra C.S.
Published: July 2006

We have examined the ability of gingival fibroblasts (GF) to participate in inflammatory response and function as accessory immune cells. The accessory immune function of GF cells was evaluated by their ability to elaborate proinflammatory cytokines following stimulation with lipopolysaccharides and interleukin‐1β (IL‐β). Using three separate clonally derived and characterized human gingival fibroblast (GF) cell lines, we demonstrate that LPS from Actinobacillus actinomycetemcomitans (Aa) and Escherichia coli (Ec) induce mRNA and synthesis of proinflammatory cytokines, IL‐1β, IL‐6 and IL‐8. IL‐1β activation of GF cells showed that IL‐1β not only induces the expression of IL‐6, IL‐8 and TNF‐α, but also acts in an autocrine manner on GF cells and induces IL‐1βexpression. Furthermore, the continuous presence of IL‐1β in GF cell cultures did not down regulate the response of GF cells to IL‐1β. Pretreatment of GF cells with IL‐lβ resulted in the enhanced synthesis of TNF‐α in response to additional IL‐lβ. These findings indicate that GF cells, in addition to providing structural support, may also function as accessory immune cells and play an important role in the initial inflammatory reaction as well as in the amplification of immune response.
Competition for peptides and amino acids among periodontal bacteria
Authors: Tang‐Larsen J. , Claesson R. , Edlund M.‐B. , Carlsson J.
Published: July 2006

We recently studied the utilization of glutathione (l‐γ‐glutamyl‐l‐cysteinylglycine), l‐cysteinylglycine and l‐cysteine by anaerobic bacteria. The rate of hydrogen sulfide formation from these compounds was determined and it was concluded that Peptostreptococcus micros and Fusobacterium nucleatum subsp. nucleatum had an active transport of small peptides. In the present study it is shown that methyl mercaptan formation from l‐methionine and l‐methionyl‐containing peptides can also be used to study peptide utilization. There were differences among the periodontal bacteria P. micros, F. nucleatum subsp. nucleatum, and Porphyromonas gingivalis in their capacity to use l‐cysteine and l‐methionine and peptides containing these amino acids. The peptides were used more efficiently by P. micros and F. nucleatum subsp. nucleatum than by P. gingivalis. All three species used the peptides more efficiently than the free amino acids. The efficiency in utilizing various amino acids and peptides may be among the key determinants of the periodontal microbial ecology.
Reactive antibodies in sera from pubertal and adult gingivitis patients against various Porphyromonas gingivalis antigens
Authors: Nakagawa T. , Nakagawa S. , Ishihara K. , Yamada S. , Machida Y. , Okuda K.
Published: July 2006

This study was undertaken to determine the immunodominant antigens from Porphyromonas gingivalis which reacted with sera from patients of pubertal and adult gingivitis. The patients with cultivable P. gingivalis and the patients without cultivable P. gingivalis were compared by immunoblots. Fifty subjects participated in this study: 20 with gingivitis, 20 periodontally healthy, and 10 with adult periodontitis. The groups with gingivitis and healthy periodontium each contained 10 pubescent subjects and 10 adult subjects. P. gingivalis was isolated from 9 of 20 patients with gingivitis and from all of 10 with periodontitis by culture study. Approximate molecular weight 43 KDa fimbriae antigen, 57, 53, 46, 28 KDa antigens from outer membrane, and 57, 44, 40, 18.5 KDa antigens from sonicated extracts of P. gingivalis reacted significantly more frequently with sera from the P. gingivalis culture‐positive gingivitis patients than with sera from the culture‐negative patients by Fisher's exact test. A molecular weight 75, 31 KDa antigen from outer membrane and a 46 KDa antigen from sonicated extract were immunodominant in sera from adult patients with periodontitis. These findings indicate that the specific antigens which reacted with sera from P. gingivalis culture‐positive patients are markers of infection with P. gingivalis. Additionally, reactivity to antigens were slightly different between sera from patients with gingivitis and those from patients with periodontitis.
Changes in periodontal treatment needs. A follow‐up study of Oslo citizens from the ages of 35 to 50 years
Authors: Hansen B. Frode , Bjertness E. , Grønnesby J.K. , Eriksen Harald M.
Published: July 2006

A random sample of 35‐year‐old subjects from Oslo took part in a dental survey in 1973 and were re‐examined in 1988. Eighty‐one subjects (85%) attended the final examination. The need for periodontal treatment was assessed by the Periodontal Treatment Need System (PTNS), and the oral hygiene by the Simplified Oral Hygiene Index (OHI‐S). The participants attended a structured interview and answered a questionnaire about general and dental health habits as well as psycho‐social factors. Only small changes in the distribution of subjects in the different PTNS categories were found to have taken place during the 15 years. In 1973, 56.8% were in need of scaling (Class B) and 32.1% had one or more deep inflamed pockets (Class C), and in 1988 the scores were 54.3% and 30.1% respectively. A logistic regression model was used to study the associations between risk factors and increased treatment need, as expressed by increase in the number of C‐quadrants. Increased number of C‐quadrants was positively associated both with short duration of education and with no interdental cleaning. Using a socio‐ecological model for periodontal diseases, variables describing the items “behaviour” and “environment” were found to be most closely associated with increased need for periodontal treatment.
Temperate bacteriophages are common among Actinobacillus actinomycetemcomitans isolates from periodontal pockets
Authors: Sandmeier H. , van Winkelhoff A.J. , Bär K. , Ankli E. , Maeder M. , Meyer J.
Published: July 2006

Actinobacillus actinomycetemcomitans is a suspected etiologic agent in destructive periodontal diseases. The detection of bacteriophages in A. actinomycetemcomitans in the subgingival plaque of patients with rapidly destructive forms of periodontitis led to the hypothesis that bacteriophage infection might increase the virulence of this bacterium (19). A. actinomycetemcomitans was isolated from 68 subjects from the Netherlands and Switzerland with localized juvenile periodontitis, rapidly progressing periodontitis, or adult periodontitis, and was tested for the presence of temperate bacteriophage with the overlay plate technique. More than half of the A. actinomycetemcomitans strains were found to release bacteriophage which formed individual plaques on indicator strains. Electron microscopy of preparations from 7 strains revealed virions with an icosahedral head and a contractile tail typical for double‐stranded DNA bacteriophages. The presence of A. actinomycetemcomitans carrying temperate bacteriophage was not correlated with the composition of the subgingival microflora nor with the clinical form of periodontal disease. Destructive periodontal disease of subjects with phage‐carrying A. actinomycetemcomitans was not more severe than of subjects with phage‐free A. actinomycetemcomitans as determined by several clinical parameters. In contrast, the pocket depth and the attachment loss were significantly lower for adult periodontitis subjects with phage‐carrying A. actinomycetemcomitans. It seems unlikely that the frequently occurring temperate bacteriophages increase significantly the virulence of A. actinomycetemcomitans.
Elevated conversion of alpha‐2‐macroglobulin to the complexed form in gingival crevicular fluid from adult periodontitis patients
Authors: Rosin M. , Benjamin P. , Rogers P. , Gibson M. , Van Leuven F. , Johnson N.W. , Curtis M.
Published: July 2006

The broad spectrum protease inhibitor, α2‐macgrolobulin (α2M), is one of the host's principal regulators of both endogenous and exogenous proteases and is likely to have an important role in the regulation of proteolytic activity at inflammatory sites. We have determined the amount of complexed (comα2M) and total α2M (totα2M) in gingival crevicular fluid (GCF) harvested from shallow and deep sites in adult periodontitis (AP) patients (n=21). An ELISA technique was developed to measure both forms of α2M in the same sample utilizing a monoclonal antibody (MAb) specific for the complexed form. In addition, protease activity towards human serum albumin (Protl), transferrin (Prot2) and Nα‐benzoyl‐L‐arginine 7‐amido‐4‐methylcoumarin‐hydrochloride (BAAMc; Prot3) were determined in a second GCF sample from the same site. Plasma α2M concentrations were only positively correlated (p=0.0163) with GCF totα2M from highly inflamed sites. We observed a significant positive correlation between totα2M and proteolytic activity in GCF from deep sites but not from shallow sites (Protl: p=0.002; Prot2: p=0.005). A similar correlation between totα2M and proteolytic activity was found at highly inflamed sites (Protl: p=0.014; Prot2: p=0.002). A very high proportion of the totα2M in GCF was in the complexed form at both shallow (71.14%±29.13) and deep sites (68.17%±28.5) Comα2M was positively correlated with proteolytic activity only in deep sites (Protl: p=0.015; Prot2: p=0.031). Our results suggest that the concentration of totα2M in the gingival crevice is positively associated with the amount of proteolytic activity at the site and that protease activities in GCF may only partly explain the high percentage conversion α2M to the complexed form. The high level of α2M inactivation in GCF from AP patients reported here may have significance not only in view of its role as a broad spectrum protease inhibitor but also through the differential effects of native vs complexed α2M on the regulation of immune responses.
Characterisation of black‐pigmented anaerobes isolated from diseased and healthy periodontal sites
Authors: Teanpaisan R. , Douglas C.W.I. , Walsh T.F.
Published: July 2006

Prevotella intermedia has recently been re‐defined and a new species, Prevotella nigrescens has been proposed. However, there is little data available on the incidence of these new species in periodontal health or disease. Black‐pigmented anaerobes isolated from diseased and healthy subgingival sites were identified by serotyping, SDS‐PAGE and physiological tests. In adult periodontitis subjects, 64% of active sites, 35.7% of inactive sites and 38.5% of healthy sites yielded black‐pigmented anaerobes. Of these, Porphyromonas gingivalis was found in 11% of active and 5% of healthy sites in diseased patients, Prevotella intermedia in 15.5% of active and 20.5% of healthy sites, Prevotella nigrescens in 37.7% of active and 11.5% of healthy sites and Prevotella denticola in 3% of active and 1% of healthy sites. In healthy subjects, 50% of sites yielded black‐pigmented anaerobes. P. gingivalis was not found in healthy subjects but P. intermedia was found in 18% and P. nigrescens in 31% of sites. SDS‐PAGE proved to be a useful method for routinely differentiating P. intermedia and P. nigrescens and two sub‐types of the latter species were detected on the basis of band pattern. Only one P. nigrescens sub‐type was found in any given individual and one type, typified by ATCC 25261, was more commonly found in deep pockets. However, overall both P. nigrescens and P. intermedia as species were just as frequently found at healthy sites as diseased sites. Thus, these species, in contrast to P. gingivalis, appear to be common commensals but they may act as opportunistic pathogens.
Characteristics of multimodal co‐aggregation between Fusobacterium nucleatum and streptococci
Authors: Takemoto T. , Hino T. , Yoshida M. , Nakanishi K. , Shirakawa M. , Okamoto H.
Published: July 2006

The co‐aggregation characteristics between Fusobacterium nucleatum and streptococci were examined to clarify the adherence factors participating in the co‐aggregation. Nineteen strains of F. nucleatum were classified into 8 groups according to co‐aggregation titer and inhibition by L‐arginine, L‐lysine and N‐acetyl‐D‐galactosamine (or lactose). The inhibition activity was, however, very different from strain to strain. With two fusobacterial strains, two inhibitors, which were both inhibition negative on their own, completely inhibited the co‐aggregation when used together in a mixture. In some co‐aggregation pairs, the protease treatment of F. nucleatum inactivated one of the adherence factors, and resulted in the change of inhibition characteristics. These results indicate the multimodal co‐aggregation of F. nucleatum with streptococci mediated by L‐arginine‐sensitive, L‐lysine‐sensitive, N‐acetyl‐D‐galactosamine‐sensitive and some resistant factors, and that the adherence factor or factors participating in the co‐aggregation change according to the co‐aggregation partners.
Periodontal variables affecting nifedipine sequestration in gingival crevicular fluid
Authors: Ellis J.S. , Seymour R.A. , Thomason J.M. , Butler T.J. , Idle J.R.
Published: July 2006

We previously demonstrated the sequestration of nifedipine in gingival crevicular fluid (GCF), especially in patients exhibiting significant gingival overgrowth. The aim of the present study is to determine the role of site specific periodontal factors in this phenomenon. 10 adult patients exhibiting nifedipine induced gingival overgrowth were studied. In each patient GCF was harvested from two sites that demonstrated inflammation and increased probing depth as well as from two clinically healthy sites. The concentration of nifedipine was determined using gas chromatography. Drug concentrations were significantly increased in the presence of inflammation (p=0.004) and plaque (p=0.029) whilst increased probing depths and gingival overgrowth were not significantly related to drug sequestration. We can conclude that inflammatory changes in gingival tissues appear to be a significant determinant for the sequestration of nifedpine in the GCF.
In vitro activity of tetracyclines, macrolides, quinolones, clindamycin and metronidazole against periodontopathic bacteria
Authors: Miyake Y. , Tsuruda K. , Okuda K. , Widowati  , Iwamoto Y. , Suginaka H.
Published: July 2006

We re‐evaluated several antibiotics including newer ones, for their in vitro killing activity, as well as their inhibitory activity, against clinical isolates of periodontopathic bacteria. Tetracyclines were active against Porphyromonas gingivalis, and were highly active against Prevotella intermedia, but demonstrated only a low killing activity against Actinobacillus actinomycetemcomitans. Rokitamycin. a new macrolide, and clindamycin were highly active against P. gingivalis and P. intermedia, but showed very weak killing activity against A. actinomycetemcomitans. Quinolones demonstrated excellent bactericidal activity against A. actinomycetemcomitans, and good inhibitory and bactericidal activity against P. gingivalis and P. intermedia. Metronidazole had an activity almost equivalent to quinolones against P. gingivalis and P. intermedia; but it was the least active against A. actinomycetemcomitans.
Biased T cell receptor V gene usage in tissues with periodontal disease
Authors: Nakajima T. , Yamazaki K. , Hara K.
Published: July 2006

In an attempt to characterize TCR V gene usage in human periodontally diseased tissue. Vα2, Vβ5.2–3, Vβ5.3, Vβ5.1, Vβ6.7, Vβ8 and Vβ12.1 expressions were examined. Serial cryostat sections obtained from 20 periodontitis and 9 gingivitis biopsies were then reacted with monoclonal antibodies directed to each repertoire. The technique was combined with a sensitive alkaline phosphatase‐anti‐alkaline phosphatase method. Peripheral blood was obtained from 10 periodontitis and 2 gingivitis patients. TCR repertoire was also quantified by flow cytofluorography with FITC‐conjugated antibodies. Cells displaying binding of each antibody were counted. The proportions to CD3‐positive cells were then calculated. The pattern of each TCR V gene product expression in inflamed gingiva exhibited individual variation, nevertheless, a consistent pattern emerged. The Vβ5 subfamily and Vβ6.7 were frequently used repertoires in gingiva, whereas the Vα2 and Vβ8 subfamily were underexpressed in most cases. Furthermore, the TCR V gene product expression in gingival tissue was biased compared with autologous peripheral blood. Three of 10 periodontitis subjects showed 1 or 2 strikingly overrepresented repertoire comparatively with autologous blood. In these 3 subjects Vβ6.7 was overexpressed in two cases and 5.2–3, Vβ8 and Vβ12.1 were overexpressed in one case. These results suggest that gingival T‐cells are not randomly mobilized from peripheral blood and that local events influence the TCR repertoire at the level of T‐cell recruitment or T‐cell expansion.
Effect of model fitting artifacts on the stepwise approach to identifying patterns of attachment loss
Authors: Cohen M. E.
Published: July 2006

The stepwise approach to the determination of periodontal attachment loss involves fitting linear, logarithmic, and exponential models to individual site data and concluding that the form of loss is consistent with the model that has the greatest r‐value, provided that the model predicts loss in excess of a site‐specific threshold. Logarithmic and exponential fits are considered to define early and late bursts, respectively, while linear fit describes loss at a constant rate. In a recently published study, the stepwise approach was applied to 6,935 sites in patients with established periodontitis and, of 581 loss detections, 195 (33.6%) were linear, 224 (38.6%) logarithmic, and 162 (27.9%) exponential. However, curvilinear patterns may occur by chance and regression algorithms that can fit such curvature may have an advantage unrelated to the true mchanism(s) of periodontal destruction. To investigate the implications of this possibility, proportions of linear, logarithmic, and exponential fit were estimated by simulation under four different conditions. These conditions incorporated random or random plus tineas change, but no nonlinear effects. The relative proportions of model fits described in the published study were approximated in all of these conditions. It would appear that the observed proportions are ubiquitous to the modelling approach itself, and do not constitute evidence of a causal nonlinear biological mechanism. The stepwise approach may be useful for detecting change but relevance to causal processes seems problematic.
Profiles of destructive periodontal disease in different populations
Authors: Baelum V. , Chen X. , Manji F. , Luan W‐M. , Fejerskov O.
Published: July 2006

In this study we evaluated the traditional view that the severity of periodontal disease varies between populations in that African and Asian populations are more severely affected than other populations. Our data on periodontal destruction in two random samples of a Kenyan and a Chinese adult population were recalculated to conform with the methods of examination and data presentation utilized in each of 6 other studies of attachment loss levels in different populations. The adult Kenyan and the adult Chinese group, who had very poor oral hygiene conditions and massive gingival inflammation, had attachment loss levels which were quite similar to those in a Japanese population (31), in a Norwegian population (27) and in a New Mexico group of adults (30). Attachment losses were similar in a population of young US adults (26) aged between 35 and 60 years relative to the corresponding Kenyan and Chinese groups while young US citizens had higher and elderly US citizens had lower mean attachment levels than either Kenyans or Chinese. Higher attachment loss levels beyond the age of 27 years were reported for a population of Sri Lankan tamil tea workers (27) and across all ages in two South Pacific island populations (29). Overall, the analysis indicates that the periodontal attachment loss profiles may differ between populations, but that these differences do not conform with the traditional generalization that African and Asian populations suffer more severe periodontal breakdown than other populations.
Comparison of randomly cloned and whole genomic DNA probes for the detection of Porphyromonas gingivalis and Bacteroides forsythus
Authors: Wong M. , DiRienzo J.M. , Lai C.‐H. , Listgarten M.A.
Published: July 2006

Whole genomic and randomly‐cloned DNA probes for two fastidious periodontal pathogens, Porphyromonas gingivalis and Bacteroides forsythus were labeled with digoxigenin and detected by a colorimetric method. The specificity and sensitivity of the whole genomic and cloned probes were compared. The cloned probes were highly specific compared to the whole genomic probes. A significant degree of cross‐reactivity with Bacteroides species. Capnocytophaga sp. and Prevotella sp. was observed with the whole genomic probes. The cloned probes were less sensitive than the whole genomic probes and required at least 106 target. cells or a mininium of 10 ng of target DNA to be detected during hybridization. Although a ten‐fold increase in sensitivity was obtained with the whole genomic probes, cross‐hybridization to closely related species limits their reliability in identifying target bacteria in subgingival plaque samples.
Immunohistochemical localization of very late activation integrins in healthy and diseased human gingiva
Authors: Del Castillo L.F. , Gómez R. Schlegel , Pelka M. , Hornstein O.P. , Johannessen A.C. , von den Driesch P.
Published: July 2006

The β1‐integrins (VLA family) are cellular adhesion molecules (CAM) that play a major role in cell‐cell and cell‐matrix interactions. The expression pattern of CAM was studied in 5 clinically normal volunteers with healthy gingiva and in 18 patients with clinically different stages of periodontitis. In healthy human gingiva α2. α3 and α6 integrin chains were found in a characteristic distribution, showing a broad continuous expression on the junctional and sulcular epithelium sites. The expression of these integrins was demonstrated primarily on the basal cell layers and in some cells of the stratum spinosum. Inflammatory stages of periodontitis revealed further upregulation of α2, α3 and α6 integrins into the junctional and sulcular epithelial cells, which correlated with the stage of the periodontitis and the extent of the cellular infiltration. α4 and α6 were found to be the predominant β1 integrin chains on inflammatory cells. The amount of δ4 and ş6 positive infiltrative cells increased with the number of inflammatory cells. VCAM‐1. the corresponding cell‐cell ligand of VLA‐4 (α4) was present on the majority of subepithelial vessels in all stages of gingivitis and periodontitis. The α5 subunit was expressed on both endothelium and gingival connective tissue cells. Samples from advanced periodontitis cases showed a higher number of a5 positive mononuclear cells. In comparison to normal epidermis, a human gingival epithelial cells express higher levels of integrins. This expression is further upregulated in advanced stages of periodontitis, indicating changes of the β1 integrin organization.
Characterization of T lymphocyte clones derived from Porphyromonas gingivalis infected subjects
Authors: Gemmell E. , Woodford V. , Seymour G.J.
Published: July 2006

Porphyromonas gingivalis plays a major role in the pathogenesis of periodontal disease, however some individuals with P. gingivalis infection do not experience periodontal breakdown. The aim of this study was to investigate the proliferative responses of two highly defined groups of subjects and to establish and characterize peripheral blood and gingival cell T cell lines and clones from subjects from these groups, The two groups were selected on the basis of P. gingivalis in their plaque and the presence of serum anti‐P. gingiralis antibodies. Both groups therefore were seen to have P. gingivalis and to have responded to it. They however differed only in their clinical susceptibility (adult periodontitis) or resistance (gingivitis) to periodontal breakdown. Dose responses of peripheral blood mononuclear cells extracted from the subjects showed a trend towards a lower response by the adult periodontitis group to P. gingivalis outer membrane (OM) antigens. Peripheral blood T cell lines and clones responsive to P. gingivalis OM were established from a high responding gingivitis subject and a low responding adult periodontitis subject. Gingival T cell lines and clones were also derived from cells extracted from the periodontal tissues of the same periodontitis subject. The majority of T cells in the peripheral blood T cell line from the gingivitis subject were CD4 while those from the adult periodontitis subject were CD8. The gingival T cell line was CD3+ve CD4‐ve and CD8‐ve. All lines and clones proliferated slowly to P. gingivalis OM but phytohaemagglutinin (PHA) induced an increase in DNA synthesis in those derived from the gingivitis subject with little to no effect on those established from the adult periodontitis subject. Furthermore. PHA inhibited the proliferative response of the CD8 clone derived from the adult periodontitis subject. Phenotypic analysis demonstrated that all the peripheral blood clones expressed the αβ TCR while the gingival T cell clones expressed the γδ TCR. All clones had the memory/primed CD45RO+ve phenotype and at least 80% of cells in each clone were HLA‐DR + ve. A lower percent of gingival cells expressed CD45RA than the CD4 peripheral blood clones and the two CD8 clones also had a decreased CD45RA expression. The gingival T cell clones also expressed a low percent CD25 as did the CD8 clone derived from the adult periodontitis subject. The results suggest that clones derived from the gingivitis and adult periodontitis subject may be functionally different. The presence of γδ T cells in adult periodontitis remains to be confirmed and their function determined.
Protein composition of whole and parotid saliva in healthy and periodontitis subjects
Authors: Henskens Y.M.C. , van den Keijbus P. A. M. , Veerman E.C.I. , Van der Weijden G.A. , Timmerman M.F. , Snoek C. M. , Van der Velden U. , Amerongen A. V. Nieuw
Published: July 2006

Cystatins are physiological inhibitors of cysteine proteinases and they are widely distributed in human tissues and body fluids including saliva. We previously reported an increased cystatin activity in whole saliva of gingivitis and periodontitis subjects. Based on this result we decided to investigate the type and origin of cystatins involved in this increased cystatin activity by collecting both whole and parotid saliva of 25 healthy and 30 periodontitis subjects. Saliva samples were quantified for cystatins S and C by enzyme‐linked immunosorbent assay and cystatin activities were measured toward papain. Besides, three other salivary proteins were determined: the plasma protein albumin, the typical parotid derived amylase and the salivary immunoglobulin IgA. The present investigation shows that levels of total protein and cystatin activity as well as the levels of glandular derived proteins amylase and cystatin C were significantly higher in whole and parotid saliva of subjects with periodontitis than in healthy controls. Cystatin S, the major salivary cystatin. however was higher in the whole saliva of the healthy group. Whole saliva concentrations of albumin and IgA, originating from sources other than the glandular cells, were not different between healthy and periodontitis subjects and were also not correlated with the typical salivary gland proteins. In conclusion, this study provides additional evidence that the human salivary glands may respond to an inflammatory disease of the oral cavity, periodontitis, by enhanced synthesis of some acinar proteins.
Cell‐bound and extracellular matrix‐associated alkaline phosphatase activity in rat periodontal ligament
Authors: Groeneveld M.C. , Van den Bos T. , Everts V. , Beertsen W.
Published: July 2006

In previous studies it was noted that alkaline phosphatase (ALP) activity in periodontal ligament does not only seem to be related to cells but may also be associated with the extracellular matrix. In an attempt to clarify this we studied the distribution of the enzyme at the electron microscopic level. In addition, ALPactivity was assessed biochemically following extraction of the ligament with (i) agents dissolving the membrane or splitting the phosphatidylinositol anchor (Triton X‐100 or phosphatidylinositol‐phospholipase C, respectively), and (ii) a matrix‐degrading enzyme cocktail (collagenase, hyaluronidase and elastase). Histochemical observations revealed (a) a heterogeneous distribution of ALP‐activity, with highest activity adjacent to the alveolar bone and (b) two pools of activity; one bound to cells and one associated with the collagenous extracelluJar matrix. In line with this were the biochemical data indicating that approximately 10% of the enzyme activity was firmly bound to the extracellular matrix and 90% to plasma membranes. Isoelectric focusing did not reveal differences between the two fractions, both samples yielding a single broad band corresponding with an isoelectric point of about 4.4.
Influence of retinoic acid on the expression of cytokeratins, vimentin and ICAM‐1 in human gingival epithelia in vitro
Authors: Gao Z. , Mackenzie I. C.
Published: July 2006

Phenotypic differences exist in viva between junctional (JE) and oral gingival (OGE) epithelia and an in vitro system has been developed that maintains phenotypic differences. This system, which permits in vitro studies of factors that may influence the epithelial phenotype, was used to investigate the effects of retinoic acid (RA) on epithelial expression of various markers known to distinguish JE from OGE. Primary cultures of JE and OGE were initiated from defined gingival regions and were subcultured and grown for 48 h in 96‐well plates or on multiple‐well slides. Control cultures were grown in medium supplemented with delipidized serum and all‐trans RA was added to experimental groups. Other cultures were grown in a defined RA‐free medium. Cultures were examined using monoclonal antibodies against cytokeratins, vimentin, and ICAM‐1 and binding displayed by indirect immunocytochemical staining. Staining reactions were assessed by direct microscopic observation and assayed by spectrophotometric quantitation. The results showed that RA had minor effects on the marker expression of JE but markedly enhanced expression of cytokeratins 8, 18, 19, vimentin and ICAM‐1 in OGE. These markers, which normally distinguish JE from OGE, were expressed at levels approaching or exceeding those of control JE cultures. These observations indicate that RA responsive mechanisms affect the phenotypes expressed by epithelia in vitro and suggest that such mechanisms may be related to the different phenotypic patterns expressed by gingival epithelia in vivo.
Production of inflammatory mediators and cytokines by human gingival fibroblasts following bacterial challenge
Authors: Dongari‐Bagtzoglou A. I. , Ebersole J. L.
Published: July 2006

Bacteria can indirectly affect the course of periodontal diseases by activating host cells to produce and release inflammatory mediators and cytokines. These mediators and cytokines, manifest potent proinflammatory and catabolic activity and may play key roles in local amplification of the immune response as well as in periodontal tissue breakdown. This study tested the effect of Actinobacillus actinomycetemecomitans (Aa) and Campylobacter rectus (Cr) challenge on PGE2, IL‐1β, IL‐6 and IL‐8 production by human gingival fibroblasts (HGF). Contact‐inhibited HGF were prepared and formalin‐killed bacterial cells (Aa JP2, ATCC 29523 & 33384 and Cr ATCC 33238) at 106‐109 were added to the HGF. Culture supernatants were collected at varying time intervals and analyzed for cytokine and mediator content. All concentrations of Aa JP2 and Cr ATCC 33238 suppressed IL‐1β production up to approximately 50% during the initial 3‐12‐h period. No bacterial concentration tested was able to increase IL‐1β production above the maximum basal levels. Both bacterial species stimulated production of IL‐6 and IL‐8. Aa JP2 did not affect PGE2 levels significantly, whereas Cr ATCC 33238 was stimulatory only at the highest concentration tested (109). There were no significant differences among the three Aa strains with respect to IL‐1β production. However, Aa ATCC 29523 and ATCC 33384 were less capable of stimulating IL‐6 secretion and more efficient in stimulating. IL‐8 production than Aa JP2. In general. Cr was the most potent enhancer of cyto‐kine and mediator production by HGF. In conclusion, Aa and Cr are capable of amplifying the local immune response and promoting periodontal tissue inflammation by stimulating HGF to secrete mainly IL‐6 and IL‐8.
Nicotine effects on PGE2 and IL‐1β release by LPS‐treated human monocytes
Authors: Payne J. B. , Johnson G. K. , Reinhardt R. A. , Dyer J. K. , Maze C. A. , Dunning D. G.
Published: July 2006

Cigarette smoking is a major risk factor in the development and further progression of periodontitis. However, little is known regarding the pathogenesis of smoking‐related periodontal diseases. The purpose of this study was to examine the effects of nicotine, alone and in combination with lipopolysaccharide (LPS), on monocyte secretion of bone‐resorbing factors, PGE2 and IL‐1β. Peripheral blood monocytes (PBM) were isolated by counterflow centrifugal elutriation from 15 healthy, non‐smoking donors. PBM were incubated for 24 h in RPMI 1640 containing nicotine (0, 50 μg/ml, I μg/ml, 10 μg/ml and 100 μg/ml) with or without 10 μg/ml Porphyromonas gingivalis LPS or Escherichia coli LPS. Culture supernatants were assayed for PGE2 and IL‐1β by ELISA. None of the nicotine preparations resulted in significant PBM secretion of PGE2 and IL‐1β above that of unstimulated cultures. However, PGE2 release was potentiated 1.7‐fold by the combination of P. gingivalis LPS and 10 μg/ml nicotine relative to P. gingivalis LPS alone (p<0.05, one‐way ANOVA). Prostaglandin E3 release also was potentiated 3.5‐fold by P. gingivalis LPS and 100 μg/ml nicotine relative to P. gingivalis LPS alone (p<0.00001, one‐way ANOVA) and 3.1‐fold by E. coli LPS and 100 μg/ml nicotine relative to E. coli LPS alone (p<0.00001, I. one‐way ANOVA). IL‐1β secretion was lower for either LPS plus 100 μg/ml nicotine relative to LPS alone, although not significantly. These data demonstrate upregulation of LPS‐mediated monocyte secretion of PGE2 by nicotine and suggest a potential role for nicotine in periodontal disease pathogenesis.
Basal layer of epithelium expresses tenascin mRNA during healing of incisional skin wounds
Authors: Aukhil I. , Sahlberg C. , Thesleff I.
Published: July 2006

Tenascin is a large oligomeric glycoprotein of the extracellular matrix that is expressed prominently during embryonic development and wound healing. Previous studies on tenascin expression in wounds have used immunohistochem‐istry to describe the expression of tenascin in wounds. The present study used in situ hybridization to identify the cells expressing tenascin mRNA in healing wounds. The results demonstrate that the cells of the basal layer of epidermis, migrating over the heating wound, are expressing the mRNA for tenascin. Intense expression was seen during the first three days after wounding, but after seven days, after the epithelium had grown to cover the wound, no tenascin transcripts were seen in epithehall cells. The epithelial cells elsewhere in the skin were devoid of tenascin transcripts at all stages examined. Previously, prominent immunohistological staining for tenascin has been located in wounds bellow the emigrating epithelial cells and it has been thought to be synthesized by stromal cells upon epithelial induction. Our findings in the present study indicate that tenascin is produced by epithelial cells, which apparently are induced to produce tenascin as they migrate after wounding.