bluuebunny/crossref_metadata_2025 huggingface dataset:
Concentrations of thiocyanate, hypothiocyanite, ‘free’ and ‘total’ lysozyme, lactoferrin and secretory lgA in resting and stimulated whole saliva of children aged 12–14 years and the relationship with plaque accumulation and gingivitis
Authors: Jalil R. A. , Ashley F. P. , Wilson R. F. , Wagaiyu E. G.
Published: July 2006

Resting and stimulated whole saliva was collected from 94 children aged 12–14 years and analyzed for thiocyanate, hypothiocyanite, ‘free’ and ‘total’ lysozyme, lactoferrin and secretory IgA. Clinical assessments of the amounts of plaque and gingival inflammation were made, and plaque was collected for determination of dry weight. An inverse relationship was observed between salivary thiocyanate concentrations in both resting and stimulated saliva and the amounts of plaque and gingival inflammation in these subjects (p < 0.05). Lactoferrin concentration in stimulated saliva was directly related to the amounts of plaque and gingivitis (p < 0.05). ‘Total’ lysozyme concentration in stimulated saliva was directly related to the amount of plaque (p < 0.05), and the ‘free’ lysozyme concentration in the same saliva was directly related to the amount of gingivitis (p < 0.05). The direct relationship observed between clinical measurements and both lysozyme and lactoferrin concentrations in saliva may have been due to contributions from gingival crevicular fluid. Cluster analysis identified three groups of subjects with different profiles in resting whole saliva, and in particular with different levels of secretory IgA. A statistically significant difference was observed in the quantity of plaque collected from subjects in two of these groups (p < 0.05). These results from cluster analysis using resting whole saliva from children confirmed the findings of a previous study with young adults.
Kinetics of CD11b expression on neutrophils isolated from subjects with healthy gingivae and patients with advanced periodontitis
Authors: Watanabe K. , Hagen K. L. , Ramakrishnan V. , Andersen B. R.
Published: July 2006

The adhesion molecule, CD11b/CD18, plays a role in host defense against bacterial infections owing to its involvement in cell migration and phagocytosis. We examined the kinetics of CD11b expression on neutrophils isolated from peripheral blood (PB‐PMNs) and gingival crevicular fluid (CF‐PMNs) in subjects with healthy gingivae and in patients with advanced periodontitis in order to assess if CF‐PMNs respond differently in regard to CD11b expression from PB‐PMNs isolated from healthy or periodontitis subjects. CF‐PMNs or formylmethionylleucylphenylalanine (fMLP)‐stimulated PB‐PMNs were incubated in buffer with or without divalent cations for 60, 90, or 110 minutes. Plasma membrane (surface) CD11b as measured by flow cytometry was found to be reduced with time when cells (PB‐PMNs or CF‐PMNs) from either controls or patients were treated with calcium‐ and magnesium‐free buffer. However, when CF‐PMNs were treated with buffer containing Ca++/Mg++, surface CD11b expression increased on cells from both controls and patients. The reduction in CD11b expression on PB‐PMNs is significantly greater than that measured on CF‐PMNs over time. Therefore, CF‐PMNs respond differently from PB‐PMNs which have been artifically stimulated with fMLP in regards to kinetics of CD11b expression on the plasma membrane.
Lectin binding to chronic inflammatory gingival tissue: possible adhesion mechanisms based on lectin‐carbohydrate interactions
Authors: Krugluger W. , Lill W. , Nell A. , Katzensteiner S. , Sperr W. , Förster O.
Published: July 2006

In this study, we analyzed the expression of different leukocyte surface antigens, of the adhesion molecules ELAM‐1 and GMP‐140 and binding of various lectins and neoglycoproteins in inflamed gingival tissue. Cell suspensions from collagenase‐digested gingiva were analyzed by flow cytometry in a FACScan. The expression of ELAM‐1, GMP‐140, carbohydrate structures and lectins in gingival specimens was also studied by immunohistochemistry. Gingival tissue of patients with active periodontal disease contained between 5% and 50% CD45+ mononuclear cells, consisting mainly of CD19+ cells (B lymphocytes). CD62, resembling GMP‐140, and ELAM‐1 were strongly expressed on endothelial cells of these patients. Control subjects usually contained almost no CD45+ cells in their gingiva and no CD62+ or ELAM‐1‐positive endothelial cells could be found in 5 of 6 control persons. Analysis of the glycosylation pattern revealed staining of infiltrating cells by peanut agglutinin (PNA; specificity for galactose), whereas soy bean agglutinin (SBA; specificity for N‐acetyl‐galactosamine) bound to epithelial cells. An endogenous lactosyl‐specific lectin could be detected on endothelial cells by binding of lactosyl‐BSA. Ulex europeus I agglutinin (UEA‐1, specific for fucose) showed selective staining of endothelial and epithelial cells. Expression of a fucose‐binding lectin, demonstrated by binding of fucosylated BSA, could be found on infiltrating cells. The adhesion molecules ELAM‐1 and GMP‐140 seem to be involved in cell adhesion during chronic inflammation of the gingiva. Interaction of other carbohydrate residues with endogenous lectins might resemble additional adhesion mechanisms inflamed gingiva.
Cell cycle‐specific growth inhibitory effect on human gingival fibroblasts of a toxin isolated from the culture medium of Actinobacillus actinomycetemcomitans
Authors: Helgeland Kristen , Nordby Øivind
Published: July 2006

A toxin isolated from the growth medium of Actinobacillus actinomycetemcomitans by ammonium sulfate precipitation was shown to inhibit irreversibly the multiplication of human gingival fibroblasts. DNA histograms from flow cytometric measurements showed that the cells accumulated preferentially in the G2 phase of the cell cycle. Such cells exhibited sheetlike protrusions, and an increased frequency of micronuclei was evident in cells treated with low concentrations of the toxin. Toxin‐treated cells were viable for several weeks, as shown by staining with trypan blue and fluorescein diacetate, and the general cell metabolism as measured by oxygen consumption was unimpaired.
Characterization of hemolytic bacteria in subgingival plaque
Authors: Hillman J. D. , Maiden M. F. J. , Pfaller S. P. , Martin L. , Duncan M. J. , Socransky S. S.
Published: July 2006

Three‐quarters of the patients with periodontal diseases surveyed in this study had one or more distinct types of hemolytic bacteria in their subgingival plaque. Twelve different species of bacteria were identified, belonging to five genera (Actinomyces, Streptococcus, Staphylococcus, Prevotella, and Actinobacillus). Nine hemolytic isolates, consisting of four Prevotella denticola strains, two Actinomyces naeslundii genospecies 2 strains, and one each of P. melaninogenica, Streptococcus constellatus, and A. naeslundii genospecies 1 strains were characterized. Incorporation of pronase into blood agar medium inhibited hemolysis by all of the isolates, suggesting a proteinaceous component for each of their hemolysins. With one exception, hemolysin production appeared to be regulated by the concentration of environmental iron: exogenous hemin was found to inhibit hemolysin production, and the iron scavenging compound, 2,2′‐dipyridyl, was found to promote hemolysin production by all of the strains except for the S. constellatus isolate. Genomic libraries of each of the hemolytic plaque isolates were prepared in Escherichia coli using pBR322. Hemolytic clones were isolated on blood agar medium containing ampicillin at frequencies ranging from 1–6.7 × 10−4. Extensive restriction mapping revealed regions of homology in the case of clones derived from three P. denticola strains isolated from the same subject. Two of the P. denticola‐derived clones were virtually identical throughout the entirety of their > 5 Kb inserts. The clone derived from the third strain showed good homology to the other two within a 1.3 Kb region, but the flanking DNA showed no homology even though all three P. denticola isolates were shown to be clonally related by ribotyping. The results indicate that hemolytic bacteria are frequently recovered from active disease sites of subjects with periodontal diseases. The hemolytic phenotype appears to be restricted to a small proportion of the total number of species normally resident in subgingival plaque. Restriction mapping suggested that a variety of hemolysin genes may be involved and that, at least in certain cases, they may be on mobile genetic elements.
Disturbances of gingival fibroblast population homeostasis due to experimentally induced inflammation in the Cynomolgus monkey (Macaca fascicularis): potential mechanism of disease progression
Authors: Nemeth E. , Kulkarni G. W. , McCulloch C. A. G.
Published: July 2006

We have studied the relationship between perturbations of fibroblast turnover in inflamed gingiva of different severities. To perform detailed spatial analyses of gingival fibroblast progenitor cells, inflammatory cell infiltrates and blood vessels, 3 Cynomolgus monkeys with healthy periodontium and 2 with naturally occurring gingivitis and ligature‐induced periodontitis were pulse‐labeled with 3H‐thymidine. Morphometric analyses of radioautographs from mid‐sagittal supra‐alveolar gingival connective tissues of incisors were performed in sites subjacent to junctional, sulcular and oral epithelium, in the body of the lamina propria and just superior to the alveolar crest. The percentage of fibroblasts incorporating 3H‐thymidine label, expressed as the labeling index (LI), was higher subjacent to the sulcular epithelium in periodontitis (1.73±0.37) than in healthy sites (1.06±0.22). This was not statistically significant (0.05 < p < 0.1) due to the small number of animals used. The sites subjacent to the sulcular epithelium also exhibited the largest increase in lymphocyte density from health to gingivitis (p < 0.01). In contrast, the LI of fibroblasts subjacent to the oral epithelium was 5‐fold higher in healthy (0.82±0.17) compared to periodontitis sites (0.13 ± 0.09; p < 0.05). Labeled fibroblasts were found close to blood vessels in all compartments and in all disease states; distance to blood vessels was reduced in inflamed sites (p < 0.10). There were increased numbers of blood vessels per unit area in the lamina propria of gingivitis compared to healthy sites. However, there were no regional differences with respect to blood vessel numbers or area in sites subjacent to junctional epithelium with different disease states. The results indicate that: 1) experimentally‐induced inflammation in the gingiva of Cynomolgus monkeys is associated with site‐specific perturbations of cell turnover; 2) fibroblast progenitors are preferentially situated adjacent to blood vessels as in the periodontal ligament; 3) the vascular response to inflammation is a generalized increase in blood vessel numbers, but not their size; 4) reactive proliferation of fibroblasts may compensate for cell death in the lamina propria but is not detectable at the site of connective tissue attachment loss subjacent to the junctional epithelium. Failure to maintain the fibroblast progenitor population may be an important component of attachment loss in progressive periodontitis lesions.
Characterization of the wheat germ agglutinin‐binding property of Treponema denticola
Authors: Grenier D. , Groleau D. , Nanci A.
Published: July 2006

Lectins were used to characterize glycoconjugates on the cell surface of Treponema denticola, a suspected periodontopathogen. Bacteria were first screened by light microscopy using fluorescein isothiocyanate‐coupled lectins. Wheat germ agglutinin (WGA) showed a high reactivity to T. denticola. While the WGA‐binding activity was accentuated following heating or detergent treatments of bacterial cells, the reaction was inhibited by incorporation of competing carbohydrates. Scanning and transmission electron microscope studies were conducted in order to characterize the distribution of the WGA‐binding sites on the cell surface of T. denticola. Data from these studies confirmed that heat treatment increases the percentage of labeled profiles and suggest that the WGA‐binding sites are concentrated on specific regions on the spirochete surface. Initial biochemical analysis indicated that the high reactivity to WGA resides in a peptidoglycan fraction.
Porphyromonas gingivalis invades oral epithelial cells in vitro
Authors: Sandros Jens , Papapanou Panos , Dahlén Gunnar
Published: July 2006

The aim of the present study was to analyze the adhesive and invasive potential of a number of P. gingivalis strains, in an in vitro system utilizing cultures of human oral epithelial cells (KB cell line, ATCC CCL 17). P. gingivalis strains W50 and FDC 381 (laboratory strains) and OMGS 1738, 1743 and 1439 (clinical isolates) as well as E. coli strain HB 101 (non‐adhering, non‐invasive control) were used. Adherence was assessed by means of scintillation counting and light microscopy, after incubation of radiolabelled bacteria with epithelial cells. In the invasion assay, monolayers were infected with the P. gingivalis and E. coli strains and further incubated with an antibiotic mixture (metronidazole 0.1 mg/ml and gentamicin 0.5 mg/ml). Invasion was evaluated by (i) assessing presence of bacteria surviving the antibiotic treatment, and (ii) electron microscopy. All P. gingivalis strains adhered to and entered into the oral epithelial cells. After 3 hours of incubation, bacteria were frequently identified intracellularly by means of electron microscopy. The cellular membranes, encapsulating the microorganisms in early stages of the invasive process, appeared later to disintegrate. The presence of coated pits on the epithelial cell surfaces suggested that internalization of P. gingivalis was associated with receptor‐mediated endocytosis (RME). Formation of outer membrane vesicles (blebs) by intracellular bacteria indicated that internalized P. gingivalis was able to retain its viability. E. coli strain HB 101 neither adhered to nor invaded epithelial cells.
Efficient and unbiased estimation of volume and area of tissue components and cell number in gingival biopsies
Authors: Verwer R. W. H. , Raber‐Durlacher J. E.
Published: July 2006

Recently, the methodology for volume and cell number estimation from sectioned tissue has undergone rapid progress. To data there are no indications in the literature that investigators in periodontal research are aware of this progress, published mainly in the disciplines of stereology and morphometry. This is unfortunate, as these developments could be profitably exploited in periodontal pathology. In this review we discuss the dangers of some currently used quantitative methods and indicate how simple unbiased methods together with an appropriate systematic sampling scheme lead to an efficient estimation of cell number and volume of tissue or tissue components.
Disposition of nifedipine in plasma and gingival crevicular fluid in relation to drug‐induced gingival overgrowth
Authors: Ellis J. S. , Seymour R. A. , Monkman S. , Idle J. R.
Published: July 2006

The present study investigates the relationship between the pharmacokinetic variables of nifedipine with the incidence and severity of gingival overgrowth in 9 adult male patients medicated with the drug for at least 6 months. Five of the patients had experienced significant gingival changes and were thus designated “responders”. The remaining four patients exhibited no gingival overgrowth, and thus acted as a control. A baseline periodontal examination (plaque scores, bleeding index and gingival overgrowth assessment) was carried out on each patient, and confined to the upper and lower anterior teeth. Serial blood and gingival crevicular fluid samples were collected over an eight‐hour investigation period. Samples were analyzed for nifedipine by gas chromatography. No significant difference (p>0.05) was seen between responders and non‐responders with regard to drug therapy, periodontal parameters or plasma pharmacokinetics of nifedipine. Nifedipine was detected in the gingival crevicular fluid of seven subjects (all responders, and two non‐responders). The peak concentration of nifedipine in crevicular fluid was 15–90 fold greater than levels observed in plasma.
Activation of serum complement by polysaccharide‐containing antigens of Porphyromonas gingivalis
Authors: Schifferle Robert E. , Wilson Mark E. , Levine Michael J. , Genco Robert J.
Published: July 2006

We previosly reported that hot aqueous phenol extraction of Porphyromonas gingivalis yields a preparation containing both lipopolysaccharide (LPS) and an antigenically distinct capsular polysaccharide (PS). In the present study, we examined the capacity of phenol‐water extracts from a number of strains of P. gingivalis to activate human serum complement. Anticomplementary activity of extracts from two invasive and two noninvasive strains of P. gingivalis was assessed in a sheep erythrocyte hemolytic assay and in an alternative pathway‐selective rabbit erythrocyte hemolytic assay. In the sheep erythrocyte assay, extracts from noninvasive strains were found to exhibit greater anticomplementary activity than extracts derived from invasive strains. A phenol‐water extract from invasive strain ATCC 53977 was further resolved into its LPS and PS fractions. Whereas isolated LPS from this strain exhibited strong anticomplementary activity, the PS fraction was only weakly active. Phenol‐water extracts from three of four strains were found to be potent activators of the alternative pathway, with extracts from the two noninvasive strains being most active. The extract from the remaining strain (ATCC 53977) was a poor activator of the alternative pathway. Further analysis of this extract revealed, however, that the LPS fraction was a potent activator of the alternative pathway, although the PS fraction exhibited negligible activity. The results of this study indicate that phenol‐water extracts of invasive and noninvasive strains of P. gingivalis differ in their respective anticomplementary activities, with invasive strains being less active. Although extracts from both invasive and noninvasive strains activated the alternative pathway, this activity appears to be attributable to the LPS, rather than the PS, component.
Attachment of T. denticola strains ATCC 33520, ATCC 35405, B11 and Ny541 to a morphologically distinct population of rat palatal epithelial cells
Authors: Keulers R. A. C. , Maltha J. C. , Wolters‐Lutgerhorst J. M. L. , Mikx F. H. M.
Published: July 2006

In the present study an assay for the attachment of T. denticola to epithelial cells is described. An indirect immunohistochemical staining method, using two native polyclonal antisera, revealed dark‐brown coloured spirochetes attached to rat palatal epithelial cell (RPE) monolayers. In addition, two morphologically distinct populations of RPE cells could be distinguished in the monolayers when using phase contrast microscopy. One minor population consisted of isolated rounded RPE cells that were lying on top of a confluent monolayer of flattened RPE cells. The rounded RPE cells were more receptive for the attachment of T. denticola than the flattened cells. The rounded RPE cells were evenly distributed over the monolayer, but the attachment of spirochetes to the rounded cells was greater at the edge than in the centre of the monolayers. The percentage of rounded RPE cells with attached spirochetes depended on the incubation time (optimum 6 h), temperature (optimum 37 C) and pH (optimum 7.0). It is speculated that the attachment of T. denticola is a physical/chemical process of yet unknown nature and that differences in the number of microvilli and/or the amount of available receptors, between the two morphologically distinct cell types, accounts for the differences in the numbers of attached spirochetes.
Periodontal repair or regeneration: structures of different types of new attachment
Authors: Schüpbach P. , Gaberthüel T. , Lutz F. , Guggenheim B.
Published: July 2006

The present study details the structural and ultrastructural features of healing events between the regenerated periodontal ligament and the root surface after experimental periodontal disease. Experiments were performed on dogs, and the concept of guided tissue regeneration was tested using resorbable polyurethane membranes. Light microscopy, scanning‐ and transmission electron microscopy were employed to determine if healing events involve regeneration (ie, process by which the architecture and the function are completely renewed) or periodontal repair (ie, healing of a wound by tissue that does not fully restore the architecture of a part). Regeneration occurred in parts of the roots only if some original cementum remained on the root surface after root planing. Repair was observed if peripheral dentin was removed by root planing as this layer was not reestablished. In areas remote from the base of the defect, new collagen fibrils, synthesized by fibroblasts and oriented perpendicular to the root surface, were spliced with severed ends of Sharpey's fiber bundles of original cementum. If circumpulpal dentin was exposed, intermingling between new fibrils with dentinal matrix fibrils occurred. In areas near the base of the defect, the first event was the formation of a cementoid by a cementoblast monolayer and subsequent formation of intrinsic fibrils oriented parallel to the root surface. Afterwards, the cementoblast monolayer disintegrated and extrinsic fiber bundles became anchored in the new cellular mixed fiber cementum. In these areas, linkage between new cementum and pre‐existing tissues always occurred by interfacial intermingling of the fibrils, regardless of whether new attachment occurred at circumpulpal dentin or original cementum.
Macaca nemestrina: a non‐human primate model for studies of periodontal disease
Authors: Persson G. R. , Engel L. D. , Moncla B. J. , Page R. C.
Published: July 2006

The non‐human primate Macaca nemestrina was evaluated for use as a potential model in periodontal research by study of 16 animals. Using one incisor, premolar, and molar per quadrant, we measured supragingival plaque, severity of gingival inflammation, and pocket depth, and analyzed the subgingival flora. Serum IgG titers and avidities to antigens of Porphyromonas gingivalis (Pg) and Actinobacillus actinomycetemcomitans (Aa) were also assessed. Ten animals were between 13 and 24 years old, and six were between 4 and 5 years old. While mean gingival inflammation scores were significantly higher for older than for for younger animals (2.2 vs 1.8, p < 0.05), mean plaque index scores and mean probing depths did not differ significantly. The animals harbored a subgingival microflora considered to be pathogenic for humans including Aa, Pg, Bacteroides forsythus, Prevotella intermedia I and II, Campylobacter recta and Fusobacterium nucleatum. Aa, however, was found only in the younger animals. All of the animals had serum IgG antibodies reactive with antigens of Pg and Aa, and titers for Pg but not for Aa were significantly higher in the older relative to the younger animals (t test p < 0.02). In contrast, antibody avidity did not significantly differ between the two groups. A combined clinical assessment index based on maximum probing depth, gingival index score, and tooth loss was used to assess the overall disease severity. Titers were positively associated with disease severity (Spearman's rank correlation 0.57, p=0.02). We conclude that M. nemestrina harbors a subgingival microflora considered to be pathogenic for humans, manifest serum IgG antibodies to antigens of Pg and Aa, and exhibits clinical features of periodontitis comparable to those seen in humans. This species appears, therefore, to be a useful model for investigating periodontal microbial‐host interactions, including the immune response.
Validation of a 21‐day, partial‐mouth gingivitis model for evaluating chemotherapeutic dentifrices
Authors: Putt M. S. , Van der Weijden G. A. , Kleber C. J. , Saxton C. A.
Published: July 2006

The experimental gingivitis model has long been used to evaluate chemotherapeutic agents in mouthrinses. Only recently however has the model been modified to test undiluted dentifrices by using a toothshield both to apply dentifrice and to protect selected teeth from toothbrushing. This also enables participants to brush the rest of the mouth and avoid the unpleasantness of 3 weeks without oral hygiene. Because of its well‐documented efficacy, chlorhexidine was used in a toothpaste formulation to investigate the validity of the partial‐mouth, experimental gingivitis model for evaluating therapeutic dentifrices. Optimal gingival health was established in 88 adults, who then were randomly assigned to two equal groups. A toothshield was constructed for each subject to fit the teeth of one mandibular quadrant. During the trial chlorhexidine or placebo dentifrice was applied undiluted to the test teeth via the toothshield, which also prevented plaque removal during brushing of the remaining dentition. After 21 days, plaque and gingivitis had developed in both groups. However, the chlorhexidine group had significantly less plaque and gingivitis than the placebo group. No adverse soft tissue effects were observed. This study demonstrated that the partial‐mouth, experimental gingivitis model allowed unhindered development of plaque and gingivitis that was comparable to whole‐mouth studies in which oral hygiene was suspended for 3 weeks. By corroborating with chlorhexidine, it is concluded that this short‐term clinical model is valid for evaluating the chemotherapeutic effects of dentifrices.
Immunopathogenesis of chronic inflammatory periodontal disease: cellular and molecular mechanisms
Authors: Seymour G. J. , Gemmell E. , Reinhardt R. A. , Eastcott J. , Taubman M. A.
Published: July 2006

Recent studies of the cellular mechanisms involved in chronic inflammatory periodontal disease (CIPD) have contributed significantly to our understanding of the pathogenesis of the disease process. Functional studies have demonstrated polymorphonuclear neutrophil (PMN) chemotactic defects in some 70% of subjects with localized juvenile periodontitis while chemiluminescence data have suggested that periphertal blood PMNs from young subjects with adult periodontitis (AP) may be in a metabolically active state. Further studies have shown that stimulation of PMNs with a number of periodontopathic bacteria resulted in the production of an IL‐1 inhibitor suggesting a possible regulatory role for PMNs in CIPD in addition to their established protective role. Most work on the immunoregulation of CIPD has, however, concentrated on T‐cells. Recent limit dilution analysis has demonstrated the presence of periodontopathic bacteria‐specific T cells in peripheral blood and the involvement and homing of these cells to the local lesions of CIPD is currently the focus of many studies. In animal studies, Actinobacillus actinomycetemcomitans (Aa)‐specific T‐cell clones home to the gingival tissues where they may exert a protective role. Homing and retention of lymphocytes to and in specific sites is dependent upon the expression of adhesion molecules. Recent data indicate however, that while there are increasing levels of ICAM‐1, LECAM‐1 and PECAM‐1 expression with increasing degrees of inflammation, there are no differences between gingivitis and periodontitis lesions. Cytokine profiles may be related to the role of T‐cell clones homing to the gingiva in CIPD. In subjects susceptible to periodontal breakdown there may be an increase in the type 2 IL‐4 producing T‐cells whereas in non‐susceptible subjects, type 1 IL‐2/IFN‐γ producing T‐cells may preferentially home to the gingiva. This hypothesis is generally supported by recent data obtained from human studies but data obtained from animal studies is only partly supportive and may suggest the opposite. Nevertheless, it is now possible to construct a testable framework or model of CIPD based on these cellular and molecular mechanisms.
Role of cytokines and inflammatory mediators in tissue destruction
Authors: Birkedal‐Hansen H.
Published: July 2006

Colonization or emergence of microbial pathogens may result in tissue destruction by activation of one or more of five distinct host degradative pathways (matrix metalloproteinase pathway, plasminogen‐dependent pathway, phagocytic pathway, PMN‐serine proteinase pathway and osteoclastic bone resorption) or by direct cleavage of extracellular matrix constituents by microbial proteinases. Activation of endogenous destructive pathways may be mediated by immune responses resulting in expression of degradative cellular phenotypes among both immigrant and resident cell populations. In addition, expression of degradative phenotypes may be triggered by direct influences on host cells of microbial products (LPS, enzymes, toxins). A body of evidence suggests that each of these mechanisms involves local production of proinflammatory cytokines and growth factors. The matrix metalloproteinase pathway is centrally involved in dissolution of all unmineralized connective tissues and perhaps in resorption of bone as well. The matrix metalloproteinase family consists of nine or more genetically distinct Zn++ endopeptidases which collectively cleave all of the constituents of the extracellular matrix. Recent studies have uncovered many essential elements of a complex, but still incomplete, regulatory network that governs tissue destruction. Proinflammatory cytokines and growth factors induce signalling pathways several of which are dependent on protein kinase C and result in transient expression of the transcription factors c‐jun and c‐fos. Initiation of transcription of most matrix metalloproteinase genes requires binding of the transcription factor AP‐1 (c‐jun/c‐fos) to a specific promoter sequence but attainment of maximal transcription rates is dependent on interaction with other promoter elements as well. Several matrix metalloproteinases have been detected in crevicular fluids and tissues of inflamed human gingiva as have the proinflammatory cytokines (IL‐1 and TNF‐α) which regulate their transcription. Although the mere presence of enzymes and cytokines does not necessarily impart function per se, these observations suggest that some level of spatial or temporal linkage exists between metalloproteinase/cytokine expression and gingival inflammation.
New clinical diagnostic strategies based on pathogensis of disease
Authors: Offenbacher S. , Collins J. G. , Arnold R. R.
Published: July 2006

The pathogenesis of periodontal tissue destruction involves the orchestrated sequential activation of several components of the host response, each of which have the potential for providing diagnostic information regarding the health or disease status of the periodontium. These events include the bacterial triggering of serum components, the release of vasoactive compounds, the recruitment of inflammatory cells, the activation of phagocytes, the local secretion of immunoglobulins and inflammatory mediators, as well as connective tissue remodeling. For purposes of diagnosis, much attention has been directed toward the measurement of local levels of specific byproducts pathogenic process either within the tissues or in the adjacent crevicular fluid. These are site‐directed assessments of the local concentration of these byproducts, and with the important exception of antibody levels, very few byproducts of the periodontal pathogenic process have been studied on a systemic level. However, since the risk associated with periodontal disease progression is primarily patient‐based and secondarily site‐based, there is an increasing need to identify patients at risk for intervention strategies. Furthermore, there are substantial data that periodontal diseases are specific infections that occur in an appropriately susceptible host. The expression of periodontal disease has a strong genetic component, which presumably defines the host's response thereby affecting susceptibility. For this reason, there is increased interest in defining those elements of the host response which result in susceptibility to disease. The ultimate objective of a diagnostic strategy is to identify patients who are potentially at risk for acquiring disease to enable preventive measures.
Adoptive transfer of suppressor T cells induced by Actinobacillus actinomycetemcomitans regulates immune response
Authors: Kurita‐Ochiai T. , Ochiai K. , Saito N. , Lkeda T. , Kurita‐Ochiai T.
Published: July 2006

Purified splenic T cells from C3H/HeN mice primed with immunosuppressive fraction (ISF) from A. actinomycetemcomitans were adoptively transferred to syngeneic mice with SRBC. The transfer of splenic T cells from mice, primed with various amounts of ISF for 6 days, resulted in the dose‐dependent inhibition of IgM anti‐sheep red blood cells (SRBC) plaque‐forming cells (PFC) compared with normal and BSA‐primed splenic T cells. Furthermore, the transfer of T cells from mice primed with 100 μg of ISF for 6 days to syngeneic and CD4‐depleted mice caused the highest inhibition. Immune suppression did not depend on the B cell population in spleen from donor mice primed with ISF, nor on haplotypes as recipient. The immunosuppressive function of these ISF‐primed T cells was abrogated by 1000 rad irradiation. Splenic T cells from ISF‐treated mice could suppress the T cell‐dependent proliferative responses of cocultured normal spleen cells in vitro. Analysis of T cell subsets of spleen cells from ISF‐treated mice showed that the suppressor cell is susceptible to treatment with anti‐CD8 and complement (C). ISF‐sensitized suppressor T cells also suppressed secondary IgG anti‐SRBC‐PFC response after immunization with SRBC in vivo depending on sensitized periods induced by ISF. Treatment of T cells from mice which primed with ISF for 8 days, with goat anti‐mouse CD8 antibody and C abrogated their suppressive effects, and secondary IgG response occurred. These results indicate that the adoptive transfer of ISF‐induced T cells, which increased suppressor function, caused the perfect blocking of immune response, allowing promotion of secondary infection.
Effect of loading on the migration of periodontal fibroblasts in the rat incisor
Authors: Michaeli Y. , Shamir D. , Weinreb Miron , Steigman Shulamit
Published: July 2006

The influence of occlusal loading on periodontal fibroblasts was investigated in hypoloaded (shortened out of occlusion), functionally loaded and hyperloaded (constant linguointrusive mechanical loads of 9.4 ± 0.06 g) lower left rat incisors. One hour following injection of 3H‐thymidine, half of the animals in each group were killed, while the remaining rats were killed 2 weeks later. The decalcified incisors were embedded in glycolmethacrylate and sectioned (2 μm) serially, perpendicularly to the long tooth axis. Labeled and unlabeled fibroblasts in the tooth‐related periodontal ligament were counted in 8 × 80μm consecutive layers. Cell density (CD) and labeling index (LI) were plotted according to their location on the apico‐incisal and cementum‐bone axes. Loading caused a decrease in CD and a shift of cells from the cementum towards the middle of the ligament, proportionally to load intensity and duration. The average tooth‐to‐bone movement of the cells was 2 μm/day in the hypoloaded and 4 μm/day in the two loaded groups. The mean daily tooth eruption rate was 975 ± 60 4 μm, 499 ± 18 μm and 103 ± 27 μm in the hypo‐, functionally‐and hyperloaded teeth, respectively. The respective concomitant average daily cell migration rates in the incisal direction were 786 μm, 500 μm and 500 μm, i.e. 80%, 100% and 485% of the tooth eruption rates. The gross disparity between cell velocity and tooth movement under conditions of restrained eruption indicates active motility of the fibroblasts, rather than their passive tooth‐eruption dependent translation.
Adhesion molecule expression in chronic inflammatory periodontal disease tissue
Authors: Gemmell E. , Walsh L. J. , Savage N. W. , Seymour G. J.
Published: July 2006

Differences in lymphocyte populations have been demonstrated in gingivitis and periodontitis lesions. A differential expression of adhesion molecules may play a role in lymphocyte trafficking in these tissues. An indirect avidin biotin immunoperoxidase technique was used to stain a range of adhesion molecules in tissue sections of 21 gingival biopsies from both gingivitis and periodontitis subjects. These specimens were placed into three groups according to the size of the infiltrate. ICAM‐1, PECAM‐1 and LECAM‐1 expression on mononuclear cells in the inflammatory infiltrates increased significantly with increasing size of infiltrate. Approximately 50% of these mononuclear cells were LFA‐1 + and CD29+. When specimens were grouped according to their putative disease status there were no significant differences between mononuclear cell adhesion molecule expression in small infiltrates from either gingivitis or adult periodontitis subjects. This was also the case with larger lesions from both clinical groups. Therefore there does not appear to be a differential expression of adhesion molecules on lymphocytes in gingivitis and periodontitis tissue. Endothelial cells were positive for ICAM‐1, PECAM‐1, CD29, GMP‐140 but negative for ELAM‐1. Keratinocyte expression of ICAM‐1 increased with increasing size of infiltrate although in heavy infiltrates, cells in the region of the junctional epithelium which were positive in small lesions, became ICAM‐1 negative. The upper layers of the oral epithelium were positive for LECAM‐1 in small infiltrates and with increasing size of infiltrate, the lower layers and many of the sulcular and junctional epithelium keratinocytes were positive. The basal epithelium and keratinocytes in the lower layers were CD29+ and in larger infiltrates, the upper layers were also positive. This study suggests that if specific homing of different lymphocyte clones occurs in gingivitis compared with periodontitis, this is not reflected in the pattern of adhesion molecule expression observed in this investigation. The present study may help to elucidate the roles played by endothelial cells and keratinocytes in lymphocyte trafficking in inflamed tissues.
Histological evaluation of interleukin‐1β and collagen in gingival tissue from untreated adult periodontitis
Authors: Feldner B. D. , Reinhardt R. A. , Garbin C. P. , Seymour G. J. , Casey J. H.
Published: July 2006

Interleukin‐1 beta (IL‐1β) may be related to the pathological processes associated with periodontitis, primarily due to its ability to induce collagenase, increase neutrophil chemotaxis, and stimulate bone resorption. This study was designed to histologically quantitate IL‐1β positive cells from various histologic fields in untreated gingivitis/early periodontitis (G/EP) versus moderate /severe periodontitis (M/SP) gingival tissues, and associate these with collagen loss. Two gingival biopsies from 8 patients were collected, one from a G/EP site and one from a M/SP site. Mouse monoclonal antibodies in combination with an avidin‐biotin‐peroxidase system were used to stain for IL‐1β, while the van Gieson method was used to stain for collagen in serial sections. Collagen loss in G/EP (35%) and M/SP (52%) fields was consistent with gingivitis and periodontitis, respectively. IL‐1β positive cells in combined coronal/sulcular (Co/Su) and apical/sulcular (Ap/Su) fields (nearest the bacterial insult) were significantly more numerous compared to combined coronal/middle (Co/Mi) and apical/middle (Ap/Mi) fields (p < 0.05). While numbers and percentages of IL‐1β positive cells were generally higher in M/SP biopsies, differences were not significant. Further, there was no correlation between the number of IL‐1β positive cells and percent collagen loss. However, a significant correlation between IL‐1β positive cells and corresponding gingival crevicular fluid IL‐1β concentrations was noted (r = 0.65, p = 0.01). Through the use of immunohisto‐chemistry, this study demonstrated that the presence of IL‐lβ+ cells does not appear to have a direct association with collagen loss.
Porphyromonas gingivalis invades human pocket epithelium in vitro
Authors: Sandros J. , Papapanou P. N. , Nannmark U. , Dahlén G.
Published: July 2006

The present study examined the adhesive and invasive potential of Porphyromonas gingivalis interacting with human pocket epithelium in vitro. Pocket epithelial tissue, obtained during periodontal surgery of patients with advanced periodontal disease, generated a stratified epithelium in culture. P. gingivalis strains W50 and FDC 381 (laboratory strains), OMGS 712, 1439, 1738, 1739 and 1743 (clinical isolates) as well as Escherichia coli strain HB101 (non‐adhering control) were tested with respect to epithelial adhesion and invasion. Adhesion was quantitated by scintillation spectrometry after incubation of radiolabeled bacteria with epithelial cells. The invasive ability of P. gingivalis was measured by means of an antibiotic protection assay. The epithelial multilayers were infected with the test and control strains and subsequently incubated with an antibiotic mixture (metronidazole 0.1 mg/ml and gentamicin 0.5 mg/ml). The number of internalized bacteria surviving the antibiotic treatment was assessed after plating lyzed epithelial cells on culture media. All tested P. gingivalis strains adhered to and entered pocket epithelial cells. However, considerable variation in their adhesive and invasive potential was observed. E. coli strain HB101 did not adhere or invade. Transmission electron microscopy revealed that internalization of P. gingivalis was preceded by formation of microvilli and coated pits on the epithelial cell surfaces. Intracellular bacteria were most frequently surrounded by endosomal membranes; however, bacteria devoid of such membranes were also seen. Release of outer membrane vesicles (blebs) by internalized P. gingivalis was observed. These results support and extend previous work from this laboratory which demonstrated invasion of a human oral epithelial cell‐line (KB) by P. gingivalis.
Isolation and characterization of a 53 kDa major cell envelope protein antigen from Treponema denticola ATCC 35405
Authors: Kokeguchi S. , Miyamoto M. , Kato K. , Tanimoto I. , Kurihara H. , Murayama Y.
Published: July 2006

A major cell envelope protein was purified from the cell envelope fraction of Treponema denticola ATCC 35405 by ion exchange chromatography after extraction with Zwittergent 3–14. Sodium dodecyl sulfate‐polyacrylamide gel electro‐phoresis showed a relative molecular mass of 53 kDa for this protein with a pI of 6.3–6.8. Amino acid analysis revealed that this protein contained high proportions of hydrophobic amino acids (40.4%), and no cysteine could be detected. The N‐terminus of the protein was blocked to Edman degradation. Rabbit antiserum raised against the purified 53 kDa protein reacted with the outer envelope of the T. denticola cell surface as confirmed by immunoelectron microscopy. This rabbit antiserum reacted with 4 of the 11 strains of treponemes tested in this study. Sera from 9 to 18 periodontitis patients reacted strongly with this 53 kDa cell envelope protein of T. denticola as determined by immunoblotting analysis.
Influence of contrast enhancement and pseudocolor transformation on the diagnosis with digital subtraction images (DSI)
Authors: Bräger U. , Bürgin W. , Marconi M. , Häsler R. U. , Lang N. P.
Published: July 2006

This study evaluated the influence of the image processing step of digital subtraction images on inter‐ and intraexaminer agreement in the interpretation of alveolar bone changes. 52 pairs of standardized radiographs from various clinical trails were included. Six dentists were invited to interpret the images projected as slides in random order. Display one demonstrated the slide of the digitized baseline radiograph and the follow‐up image. Display two showed the regular digital subtraction image. Display three represented a grey level contrast enhanced version and displays four and five were pseudo/color enhanced subtraction images. Applying κ‐statistics and multiple regression analysis it was demonstrated that better agreements were obtained when the two color coded displays of subtraction images were shown to the interpreters. The image interpretation was performed in two series. For the first evaluation the interpreters were not informed about the therapy provided nor the time elapsed between taking the pairs of standardized radiographs. In the second series this information was provided. It could be demonstrated that the agreement in the diagnosis of bone change was less influenzed by the knowledge about the clinical information if the two color‐converted versions of subtracted images were evaluated. Thus, it was concluded that image processing of subtraction images using color enhancement might improve agreement in the diagnostic task. The color coded images were less influenced by the bias in the interpretation of an expected change. The decision making process might be more objective when using color enhanced subtraction images.
Immunolocalization of matrix metalloproteinases and TIMP‐1 (tissue inhibitor of metalloproteinases) in human gingival tissues from periodontitis patients
Authors: Meikle M. C. , Hembry R. M. , Holley J. , Horton C. , McFarlane C. G. , Reynolds J. J.
Published: July 2006

The matrix metalloproteinases (MMPs) collagenase, gelatinase A (72 kDa gela‐tinase), stromelysin, and their specific inhibitor TIMP‐1 (tissue inhibitor of metalloproteinases), were immunolocalized using specific polyclonal antisera in gingival tissues from 21 patients with chronic inflammatory periodontal disease. Monoclonal antibodies against macrophages (Leu‐M5), B cells (Leu‐14), helper T cells (OKT4), suppressor T cells (OKT8) and the HLA‐DR epitope were also used to identify leukocyte subsets. MMPs were observed in connective tissues at sites that histologically showed signs of remodelling. The number and distribution of positive cells varied widely, however, not only between individual biopsy specimens, but also within the same specimen. The same was true for the composition and distribution of the inflammatory cell infiltrate. Moreover, although there was a positive correlation between the number of MMP‐producing cells and the severity of inflammation in some specimens, for others with comparable leukocyte subset scoring the number was reduced and sometimes absent altogether. Cells secreting MMPs were fibroblasts, macrophages and epithelial cells. It was not possible to determine unequivocally whether a MMP‐positive cell within the connective tissue was a fibroblast or a macrophage, since the antisera recognise both fibroblast and macrophage MMPs and the different fixation requirements for MMPs (4% paraformaldehyde) and Leu‐M5 (acetone) precluded co‐localization on the same section. TIMP‐1 was immunolocalized within connective tissue cells at sites of tissue remodelling. Our results support the hypothesis that tissue‐derived MMPs may be involved in tissue remodelling in periodontal disease and conclusively demonstrate that epithelial cells may be involved as well as connective tissue cells.