bluuebunny/crossref_metadata_2025 huggingface dataset:
Cell generation within the interdental gingival septum of the rat
Authors: Pender N. , Heaney T. G.
Published: July 2006

The aims of this investigation were to determine whether connective tissue progenitor cells in the interdental gingival septum (IGS) have a paravascular origin, and how the distribution of 3HTdR‐labelled cells within the IGS changes with time after a single injection. 30 male hooded Lister rats aged 6 weeks, were killed in groups of ten, 3, 75 and 171 h after a single injection of tritiated thymidine. Autoradiographs were examined of 3 transverse Historesin sections of the papilla between second and third mandibular molars in 29 specimens, taken at equidistant intervals between the col and alveolar bone crest. At all times and levels, 73.9–93.0% of labelled cells and 72.0–79.0% of unlabelled cells lay within 50 μm of blood vessels (BVs). The highest percentages of labelled cells (PLCs) occurred within 5 μm of BVs (P < 0.001) although mean nuclear density here was lowest (P < 0.017), and there was a significant diminution of PLC (P < 0.05) with increasing distance from BVs, occurring most precipitously 5–10 μ from vessel walls. Sites of significantly increased PLC at 3 h also approximated to sites in which mean BV densities were greatest. At 3 h, a number of discrete sites with significantly increased PLCs (P < 0.05) were found within two zones, each equivalent to 40% of IGS volume and juxtaposed with each tooth. At later times, additional sites of raised PLC appeared throughout the IGS. Overall PLCs in the upper two levels and within 5 μm of BVs also increased over the timecourse (P < 0.01). These data are consistent with the existence of paravascular connective tissue progenitor cells within the outer zones of the IGS closest to the teeth. Labelled cell distributions at 75 h and 171 h did not provide firm evidence of translocation within the IGS.
Proliferative potential of the attached cells of human junctional epithelium
Authors: Salonen J. I.
Published: July 2006

Samples of the attached cells of junctional epithelium (DAT cells) were obtained during extractions of eight erupted bicuspids from young healthy subjects. Each extracted tooth, with its layer of living DAT cells, was incubated for three hours in minimum essential medium (MEM) containing 5 μCi/ml of 3H‐thymidine, and prepared for autoradiography. An average of 3 labeled cells per 1 mm of the epithelial attachment was found along the vertical dimension of the tooth. The attachment of an individual cell to the tooth surface was found to be a prerequisite for the cell's DNA synthesis suggesting that the tooth has a nonspecific epigenetic role in defining the functional phenotype of the DAT cells. Even the most coronal DAT cells located about 200 μm apical from the plaque border, were found to synthesize DNA. The finding suggests that mechanisms which regulate the multiplication of DAT cells are involved in the preservation of the integrity of the dentogingival junction.
Cellular origins and differentiation control mechanisms during periodontal development and wound healing
Authors: Pitaru S. , McCulloch C. A. G. , Narayanan S. A.
Published: July 2006

In the context of cellular origins, ondotogenic epithelium and oral epithelium are the sources for junctional epithelium during development and during wound healing respectively. In contrast, both odontogenic and non‐odontogenic mesenchyme contain the progenitors for gingival fibroblasts in developing tissues while in wounded tissues, gingival fibroblasts are derived from gingival connective tissues and comprise a heterogeneous population of cells with diverse properties and functions. Periodontal ligament, bone and cementum cell populations apparently originate from dental follicle progenitor cells during development, but during wound healing derive from ancestral cells in periodontal ligament and bone. Cellular differentiation in developing periodontium is governed in part by epithelial‐mesenchymal interactions that generate specific signals which regulate selective cell populations in time and space. On the other hand, differentiation during wound healing and regeneration is regulated by a vast array of extracellular matrix informational molecules and by cytokines that induce both selective and non‐selective responses in the different cell lineages and their precursors. Further, several important signalling systems are irretrievably lost after development is complete. Thus, in the context of cellular origins and differentiation, developing and wounded periodontal tissues exhibit fundamental differences. Future prospects for improved healing and regeneration of periodontal tissues may derive from identification and isolation of informational molecules that are stored in connective tissue matrices. These molecules and elucidation of their functions may open new perspectives in our understanding of the biology of periodontal wound healing and may provide novel approaches to periodonlal regeneration.
Chemoluminescence generation and MTT dye reduction by polymorphonuclear leukocytes from periodontal disease patients
Authors: Gomez R. S. , da Costa J. E. , Lorentz T. M. , de Almeida Garrocho A. , Nogueira‐Machado J. A.
Published: July 2006

Alterations of polymorphonuclear leukocytes (PMNs) functions have been reported in patients with severe forms of some periodontal disease. In this study we evaluated the chemoluminescence generation and MTT dye reduction by human PMN in patients with juvenile periodontitis (JP), rapidly progressive periodontitis (RPP) and adult periodontitis (AP) during protein kinase C (PKC) activation or during the phagocytosis of opsonized zymosan. The results demonstrated that only PMNs of JP patients showed a decreased chemoluminescence generation and MTT dye reduction during the phagocytosis of opsonized zymosan (p < 0.05). The time to reach the maximal peak during the PKC activation on the chemoluminescence reaction was evaluated and JP PMNs patients demonstrated a depressed value (7.0 ± 0.4 min) compared with healthy volunteers (13.8 ± 0.5 min). The etiology and importance of such cellular alterations in the immunopathogenesis of the periodontal disease are discussed.
Inhibitory effect of aspirin on root resorption induced by mechanical injury of the soft periodontal tissues in rats
Authors: Kameyama Y. , Nakane S. , Maeda H. , Fujita K. , Takesue M. , Sato E.
Published: July 2006

The purpose of the present study was to study histologically and histometrically the inhibitory effect of aspirin on root resorption induced by mechanical injury of the periodontal soft tissues in rats. Resorption lacuna in the root surface of the molar in animals given both mechanical injury and aspirin administration contained fewer odontoclasts and was smaller in length and area than that in animals given only mechanical injury. The result of the present investigation indicated that the administration of aspirin might suppress root resorption induced by mechanical injury of the periodontal soft tissues.
Studies of the angular reproducibility of positioning patients adjacent to an x‐ray tube: 1. Stent‐rod based and extra‐oral systems
Authors: Allen K. M. , Hausmann E. , Kutlubay M. E. , Loza J. , Carpio L. C. , Ortman L. , Wobschall D.
Published: July 2006

The usefulness of subtraction radiography for detecting small changes in crestal bone is dependent upon achieving reproducible geometry between x‐ray beam and patient structures when serial radiographs are taken. This study evaluates 2 methods currently employed to maintain geometric correspondence: 1) a stent‐based system which rigidly fixes a custom‐made stent to the x‐ray tube by the use of a rod and 2) an extra‐oral system which positions a patient in the x‐ray unit by means of ear rods. The projection of a light beam from a fixed subject reference was used to measure the change of the orientation of the reference at 2 different measurement times. The rod‐stent system was able to maintain a discrepancy of less than 2 75% of the time over a time period of 6 months. For the extra‐oral system this ranged from 72% to 92% during a 1‐month period.
Increased respiratory burst activity is associated with normal expression of IgG‐Fc‐receptors and complement receptors in peripheral neutrophils from patients with juvenile periodontitis
Authors: Leino L. , Hurttia H. M. , Sorvajärvi K. , Sewon L. A.
Published: July 2006

The respiratory burst activity in peripheral neutrophils from nine patients with localized juvenile periodontitis (LJP) and age‐ and sex‐matched healthy controls was studied by measuring the intensity of luminol‐enhanced chemiluminescence (CL) induced by unopsonized and three differently opsonized zymosan particles, formyl‐methionyl‐leucyl‐phenylalanine (FMLP) or phorbol myristate acetate (PMA). The neutrophils from LJP patients showed in general more intense CL with all activators than did their controls. Particulary, the CL response induced by unopsonized zymosan particles and FMLP were significantly higher (p < 0.05 and 0.001). When comparisons were made between female LJP patients (n = 6) and matched controls, also serum‐opsonized and IgG‐opsonized zymosan particles produced CL was significantly increased (p < 0.05). In order to determine whether the elevated CL responses to zymosan particles were due to altered levels of the interacting receptors on neutrophil surface, an immunofluorescence analysis of the expression of IgG‐Fc‐receptors (FcR) and complement receptors (CR) was performed with flow cytometry. No significant difference in the expression of FcRII, FcRIII, CRl and CR3 was detected in LJP group compared to controls. Since the elevated CL responses can not be explained by changes in receptor numbers it is hypothesized that the increased respiratory burst activity in LJP may be caused by altered post receptor signalling pathway.
Cytokeratin profile of the junctional epithelium in partially erupted teeth
Authors: Feghali‐Assaly M. , Sawaf M.H. , Serres G. , Forest N. , Ouhayoun J. P.
Published: July 2006

This study uses cytokeratins (CK) as markers to investigate the phenotype of the junctional epithelium (JE) in partially erupted human teeth. The gingival samples, which were clinically healthy, were carefully dissected from the teeth. Cryostat sections were cut for histological staining, immunofluorescence microscopy and gel electrophoresis. Cytokeratins were extracted after microdis‐section. The basal and suprabasal epithelial cell markers, cytokeratins 4, 5, 13, 14 and 19 were detected with specific monoclonal antibodies. They showed that the junctional epithelium in erupting teeth has a complex topography. The cytokeratin immunohistochemical profile distinguished between the primary junctional epithelium (CK 5, 14 and 19 in basal and suprabasal cells and CK 13 faintly stained throughout the suprabasal layers) and the adjacent epithelium that had the same cytokeratin profile as the sulcular epithelium (CK 5, 14 and 19 in basal cells and CK 4 and 13 intensively stained in the suprabasal cells). Extraction, two‐dimensional electrophoresis and western blotting showed that this transitional JE during eruption also contained CK 6, 16 and perhaps CK 4. Thus, the JE in erupting teeth shows patterns of CK distribution that are very similar to that of developing oral epithelia.
Regeneration of junctional epithelium and its innervation in adult rats: a study using immunocytochemistry for p75 nerve growth factor receptor and calcitonin gene‐related peptide
Authors: Redd P. E. , Byers M. R.
Published: July 2006

Junctional epithelium (JE) is a rapidly proliferating tissue that connects the gum to the tooth, that provides a free surface for bidirectional movement of substances between the body and the oral cavity, and that participates in defense against bacterial infection. It is innervated by numerous sensory nerve fibers that are immunoreactive (1R) for neuropeptides such as calcitonin gene‐related peptide (CGRP), and for low affinity nerve growth factor receptor (p75‐NGFR). Basal epithelial cells of the JE and of adjacent sulcular epithelium also have intense p75‐NGFR‐IR. In the present study we removed a wedge of the free gingiva and JE from the anterior side of the maxillary first molar of adult rats, and then studied the return of nerve fibers during tissue regeneration from 1–63 days after gingivectomy. The nerve fibers entered the adjacent healing sulcular epithelium before innervating the new JE. in both cases prior to return of epithelial cell p75‐NGFR‐IR. The regenerating nerve fibers completely bypassed the zone of epithelial down‐growth (long junctional epithelium, LJE) that was briefly present along the tooth from 1–3 weeks after injury. The LJE did not have p75‐NGFR‐IR and was gradually replaced by a modified thicker regenerated junctional epithelium (RJE). The RJE was attached along the injured root surface, had numerous nerves in basal layers, and it had begun to regain p75‐NGFR‐IR staining of basal epithelial cells by 22 d. Regenerating nerve fibers at 6–10 d had unusually weak CGRP‐IR and greatly increased p75‐NGFR‐IR. Both nerve stains had returned to normal by 3–6 weeks. The intense p75‐NGFR‐IR of regenerating nerves was found on both axonal and Schwann cell membranes using electron microscopic immunocytochemistry. In both the normal and regenerating JE, nerve fibers were rare in the attachment layers next to the anterior side of the maxillary first molar, compared to well‐innervated basal layers. The complete avoidance of LJE by regenerating nerve fibers and its lack of p75‐NGFR‐IR suggest that its functions do not require innervation and that it does not make neurotrophic growth factors.
Intra‐/inter‐examiner reproducibility study of gingival bleeding
Authors: Van der Weijden G. A. , Timmerman M. F. , Saxton C. A. , Russell J. I. , Huntington E. , Van der Velden U. , Van der Weijden Fridus
Published: July 2006

Sulcular bleeding after stimulation with a periodontal probe has been associated with the presence of an inflammatory lesion in the gingiva. The objective of this study was to evaluate the effect of the placement of the probe in relation to the tooth surface, and the effect of standardising the probing pressure on the intra‐ and inter‐examiner reproducibility of the gingival bleeding when using a well‐defined bleeding index. Four different variations were defined: parallel bleeding index (ParBI): when the probe is run along the marginal gingiva it is held parallel to the tooth surface. Angulated bleeding index (AngBI): the probe is held at an angle of approximately 60° to the longitudinal axis of the tooth and in contact with the sulcular epithelium. Controlled force parallel bleeding index (CF‐ParBI)/controlled force angulated bleeding index (CF‐AngBI): the same procedure as described for the ParBI and AngBI is followed, but instead of a conventional (WHO‐ASH/Dentsply(r)) probe an adjustable force probe (Brodontic(r)‐ASH/dentsply), adjusted to 0.25 N is used. The results show that the agreement both within and between clinicians could hardly be rated as ‘fair’ on a site basis. Approximately one in every three sites was given a different assessment on the second examination. This might have been the consequence of the repeat examination. Agreement on a quadrant basis was slightly better. Furthermore, the direction of the probing influences the number of provoked bleeding sites. Angulation of the probe produces consistently less bleeding compared with parallel placement of the probe.
Periodontal conditions of teeth autogenously transplanted by a two‐stage technique
Authors: Nethander G.
Published: July 2006

Inflammatory reactions of the marginal periodontal tissues and loss of attachment could partly account for the often occurring rejection of autogenously transplanted mature teeth. The periodontal conditions of transplanted teeth were investigated from 1 month up to 5 years postoperatively. The parameters plaque, bleeding on probing to the bottom of the pocket, probing pocket depth (PPD), gingival recession and probing attachment loss were analysed by multiple regression analysis. No significant difference was found between transplanted and control teeth in bleeding on probing the bottom of the pockets up to 5 years postoperatively with the exception of increased bleeding on probing of the transplanted teeth at the 1‐month postsurgery examination. No significant difference of the mean probing depth between transplanted teeth and control teeth was found at the mesio‐ and distobuccal surfaces. The transplanted teeth at the buccal surface showed increase of the mean pocket depth during the observation period. Increased mean probing depth without progression over time was found at the transplanted teeth compared to the controls at the distolingual, lingual and mesiolingual surfaces. A small mean gingival recession at the transplants was observed. Loss of attachment was recorded at 13% of the surfaces. Totally 50% of the transplants showed loss of attachment and 5% were removed because of extensive attachment loss. On 13% of the transplanted teeth with loss of attachment, root resorption was also found.
Expression of membrane alkaline phosphatase activity on gingival fibroblasts in chronic inflammatory periodontal disease
Authors: Abe T. , Akamine A. , Hara Y. , Maeda K.
Published: July 2006

We investigated the expression of membrane alkaline phosphatase (ALP) activity on fibroblasts in inflamed gingiva from 7 patients with adult periodontitis. ALP activity was ultrahistochemically detected by a cerium‐based capture method. The degree of ALP activity was estimated by morphometric analysis of the percentage of the perimeter on which ALP reaction product was deposited. Fibroblasts in the non‐inflammatory connective tissue were surrounded by bundles of collagen fibrils, and the majority of these fibroblasts showed ALP‐negative or weakly ALP‐positive reaction. By contrast, fibroblasts in the inflammatory connective tissue were either surrounded by a non‐collagenous substance or in contact with inflammatory cells, and the majority of these fibroblasts showed a strong ALP‐positive reaction. These results suggest that the expression of membrane ALP activity on gingival fibroblasts is induced by microenvironmental changes associated with the loss of contact between the cells and the extracellular collagenous matrix during inflammatory reactions.
The effect of temperature on the discharge of periodontal ligament mechanoreceptors in the cat canine tooth
Authors: Linden R. W. A. , Millar B. J.
Published: July 2006

The response of periodontal ligament mechanoreceptors to mechanical stimuli was studied at different temperatures in anaesthetized cats. Recordings were made from functionally single fibres in the inferior alveolar nerve from mechanoreceptors which were located in the ligament by dissection and punctate stimulation and electrical stimulation. A thermode was used to alter and maintain small areas of periodontal ligament at temperatures ranging from thermode tip temperatures of 30C to 57°C. The response to ramp‐plateau mechanical stimuli applied to the tip of the crown of the canine tooth was greatest when the thermode temperature was 37.5°C±6.5°C. The effect was similar for all receptors studied.
Effects of cytokines on gingival fibroblasts in vitro are modulated by the extracellular matrix
Authors: Irwin C. R. , Schor S. L. , Ferguson M. W. J.
Published: July 2006

Fibroblast function in gingival tissue is thought to be regulated by the local cellular environment – both the extracellular matrix and soluble factors. In an attempt to artificially re‐create this situation fibroblasts have been cultured within 3‐dimensional collagen gels in an environment more physiologically comparable to connective tissue. Using such a model we investigated the effects of the extracellular matrix on gingival fibroblast growth and synthetic activity and on the cellular responsiveness to 4 soluble factors – epidermal growth factor (EGF), platelet‐derived growth factor (PDGF), transforming growth factor‐beta (TGF‐β1) and interleukin‐1β (IL‐1β). Fibroblasts cultured within collagen gels showed similar growth rates, an increased production of collagen but reduced levels of hyaluronan synthesis in comparison to cells in monolayer culture. Cellular responsiveness to soluble mediators was also modulated by the collagen matrix, with a generalised reduction in response by cells embedded within the matrix. The stimulatory effects of EGF and PDGF on cell growth in monolayer over a 14‐day period were only found during the initial stages of culture within gels. Similarly the stimulation of matrix production by cells induced by TGF‐β1, on plastic was reduced or even negated when cells were cultured in collagen gels. On plastic IL‐1β significantly stimulated cell growth but had no effect on either collagen or hyaluronan production by fibroblasts. In gel cultures, this cytokine had no effect on cell proliferation, but significantly inhibited both collagen and hyaluronan synthesis. These findings further illustrate the usefulness of fibroblast‐populated collagen gels as a model system for studying the modulatory effects of soluble factors and extracellular matrix molecules on fibroblast function in vitro.
Prostaglandin E2 and interleukin‐1 levels in smokeless tobacco‐induced oral mucosal lesions
Authors: Johnson G. K. , Poore T. K. , Squier C. A. , Wertz P. W. , Reinhardt R. A. , Vincent S. D.
Published: July 2006

Inflammatory mediators released as a result of smokeless tobacco (ST)‐induced irritation may play a role in the development of oral mucosal lesions at habitual tobacco placement sites in ST users. The present study examined levels of interleukin‐1 (IL‐1) and prostaglandin E2 (PGE2) in ST‐induced mucosal lesions and compared these to mediator levels in clinically normal mucosa. Soft tissue biopsies were obtained from white mucosal lesions at habitual placement sites and normal alveolar mucosal tissue at non‐placement sites in 18 ST users. Fifteen non‐tobacco using subjects also provided normal alveolar mucosal biopsies. IL‐1 and PGE2 were recovered from the specimens, and mediator levels were determined by enzyme immunoassay. Prostaglandin E2 levels (pg/mg) were lower in both regions in the ST subjects, but values did not vary significantly between the regions with 2.77±0.72 and 2.86±0.99 at placement and non‐placement sites, respectively, in ST users and 7.31±3.84 in non‐tobacco users. Both IL‐1α and IL‐lβ (pg/mg) were significantly (p < 0.0I) elevated in ST lesions (IL‐lã=25.56±4.00; IL‐1β=7.76±1.68) compared to either non‐placement sites in ST users (IL‐lα=14.64±2.65; IL‐lβ=1.63±0.72) or non‐tobacco users (IL‐lα=12.84±2.60; IL‐lβ=2.04±0.75). In view of IL‐l's role in keratinocyte proliferation and its inflammatory effects, this cytokine may contribute to mucosal and gingival alterations observed in ST users.
Model fit and measurement outcome in attachment measurements: a simulation study
Authors: Allen K. , Hausmann E.
Published: July 2006

Serial attachment level measurements were simulated based on 2 hypothetical models of true change: 1) a burst model, where attachment changes rapidly over the duration of one measurement interval, but is unchanging before and after, and 2) a linear model, where attachment changes at a constant rate over time. Normally distributed measurement error was added to the modeled attachment level change to produce the series of measurement simulations. It was then determined for each series whether a burst model or a linear model best fit the simulated measurement series for a range of overall attachment level changes. For series generated by a burst model, the burst model fit better than a linear model a significant proportion of the time at all attachment level changes. However, for series generated by a linear model, the burst model provided the best fit for attachment level changes that were less than 4 times the standard deviation of the measurement error. Estimates of change based on a linear model slightly overestimated change when the true underlying model was a burst model. Estimates of change based on a burst model slightly underestimated change when the true model was a burst model, but substantially underestimated change when the underlying model was a linear model. Model fit when assessed by the least squares criterion may not be a reliable guide to model validity.
Identification and possible function of cathepsin G in gingival crevicular fluid from chronic adult periodontitis patients and from experimental gingivitis subjects
Authors: Kunimatsu K. , Mine N. , Muraoka Y. , Kato I. , Hase T. , Aoki Y. , Yamamoto K.
Published: July 2006

The levels of cathepsin G in gingival crevicular fluid (GCF) from chronic adult periodontitis patients and experimental gingivitis subjects were determined both by activity measurement using N‐benzoyl‐(DL)‐phenylalanine‐2‐naphthyl ester as a substrate and by enzyme immunoassay using anti‐human cathepsin G IgG. The activity level of cathepsin G in GCF of both periodontitis and experimental gingivitis has no significant correlation with all measured clinical parameters. Western immunoblotting using antibodies specific for cathepsin G or α1‐proteinase inhibitor revealed that the difficulty in demonstrating the association of its activity with the severity of these diseases was due largely to formation of the enzyme‐inhibitor complexes. By contrast, statistically significant positive correlation was found between cathepsin G content in GCF of periodontitis, which was determined by enzyme immunoassay, and such clinical parameters as the GCF volume, the gingival index and probing depth. The increased cathepsin G content with increasing severity of periodontal inflammation was markedly diminished by the initial treatment. Although no significant activity was detectable in GCF of experimental gingivitis, a rapid increase of the immunoreactive cathepsin G was found in GCF at 3–5 d after refraining from oral hygiene measures, which rapidly decreased by 10 d. The progressively increased cathepsin G between 10th and 21st d rapidly decreased by cleaning of the teeth. The results indicate that cathepsin G is involved in the host's defensive mechanism against the invasion of etiologic microbes and/or the development of either periodontitis or gingivitis.
Elastin derived peptides protect elastic fibres degradation by human neutrophil elastase: in vitro and in vivo studies using a mechanically induced rat gingival inflammatory model
Authors: Bonnaure‐Mallet M. , Godeau G. , Tixier J. M. , Lebon‐Pelletier P. , Chambon Y. , Robert L. , Homebeck W.
Published: July 2006

An elastin peptide (kE57) obtained from organoalkaline hydrolysis of calf ligamentum nuchae insoluble elastin, was isolated by gel permeation on Sephadex G150 and high performance liquid chromatography on a TSK G 3000 SW column. It possessed an average Mr=57,000 and similar amino acids composition as its insoluble counterpart. KE57 behave as a competitive inhibitor of human neutrophil elastase (HNE) with KI=1.4 μM; it also inhibited porcine pancreatic elastase (PPE) but less efficiently KI=180 μM. Identification of elastic fibres in rat gingiva was ascertained by light and electron microscopic studies. Morphometric studies indicated that rat gingiva contained similar levels of elastic fibres (=2%) as human skin; elastic fibres networks from both tissues also displayed high structural analogy. Gingival chronic inflammation was induced in rats by mechanical impaction associated with an hyperglucidic diet. After 5 weeks, the levels of rat gingiva elastic fibres, decreased from Vv= 1.94±0.1% to Vv= 1.02±0.06%. Local injections of kE57: 100 μig per day, 5 days a week for 5 weeks did restore the integrity of the gingiva elastic fibres network: Vv= 1.84±0.1. Without influencing leucocyte infiltration, it is proposed that elastin‐derived peptides, acting as potent competitive inhibitor of neutrophil elastase involved in periodontitis, might be of therapeutic value.
Ultrastructural localization of glycosaminoglycans in human gingival connective tissue using Cupromeronic blue
Authors: Erlinger R. , Willershausen‐Zönnchen B. , Welsch U.
Published: July 2006

Human gingiva was stained with cupromeronic blue according to Scott's critical electrolyte concentration technique in order to localize glycosaminoglycans (GAG) in the electron microscope. Identification was performed by digestion with chondroitinase AC, ABC and heparinase. The GAG were localized in three compartments of the connective tissue: the supra‐alveolar fiber apparatus, the loose connective tissue and the basement membranes. In the supra‐alveolar fiber apparatus, consisting mainly of densely packed parallel collagen fibrils, dermatan sulfate GAG are regularly attached to the d‐band of the collagen fibrils. The precipitates (6–7 nm in diamter) aggregate to thicker precipitates (up to 16 nm), thus possibly providing stability to the fiber system. In the loose connective tissue with sparse collagen fibrils dermatan and chondroitin sulfate GAG form very large precipitates (up to 30 nm in diameter and 400 nm length) which interconnect the few collagen fibrils. The basement membranes of the epithelium and capillary endothelium contain heparan sulfate GAG as fine precipitates (4–6 nm in diameter) which form a meshwork. These findings are consistent with the Scott model (1) for the interactions among glycans and glycans and collagen fibrils in connective tissues.
Lipopolysaccharides from periodontal pathogens prime neutrophils for enhanced respiratory burst: differential effect of a synthetic lipid a Precursor IVA(LA‐14‐PP)
Authors: Aida Y. , Kukita T. , Takada H. , Maeda K. , Pabst M.J.
Published: July 2006

When neutrophils are incubated with bacterial lipopolysaccharide (LPS), they become primed for enhanced release of superoxide anion (O2−) in response to stimulation by FMLP. We investigated the human neutrophil‐priming activity of LPS from the periodontal pathogens, Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi) and Actinobacillus actinomycetemcomitans (Aa) in comparison with that of LPS from Escherichia coli (E. coli). The optimum conditions for LPS to prime neutrophils were assessed for every LPS and found to be as follows: Neutrophils were incubated with LPS in the presence of 10% heat‐inactivated plasma and 1 mM EDTA at 37°C for 30 min and then stimulated with 1 μM FMLP at 37°C for 7 min. Under these conditions, half‐maximum priming was observed at 6.2 ng/ml Pg‐LPS, 45 ng/ml Pi‐LPS, 1.5 ng/ml Aa‐LPS and 1.5 ng/ ml E. coli‐LPS. The priming activity of each LPS was neutralized by polymyxin B. Anti‐CD14 monoclonal antibody inhibited priming by all LPS. The priming by Aa‐LPS and E. coli‐LPS was inhibited by LA‐14‐PP, a synthetic lipid A precursor IVA, but that by Pg‐LPS and Pi‐LPS was not. Priming by tumor necrosis factor alpha was not affected by polymyxin B, anti‐CD14 antibody or LA‐14‐PP. Gelation of Limulus amebocyte lysate occured at 10 pg/ml Pg‐LPS, 30 pg/ml Pi‐LPS, 3 pg/ml Aa‐LPS and 3 pg/ml E. coli‐LPS. Thus LPS from different periodontal pathogens primed neutrophils with different efficacy. The difference in the sensitivity to LA‐14‐PP among the four LPS tested raises the possibility that the mechanism of host response to Pg‐LPS or Pi‐LPS may be different from that to Aa‐LPS or E. coli‐LPS.
Bacterial steroidogenesis by periodontal pathogens and the effect of bacterial enzymes on steroid conversions by human gingival fibroblasts in culture
Authors: Soory M.
Published: July 2006

Studies were performed to investigate the effect of microbial culture supernatants of periodontal pathogens on the metabolism of radiolabelled testosterone in the presence or absence of human gingival fibroblasts. Subgingival plaque samples were obtained on paper points from 3 sites with probing depth values of 6–8 mm. Samples were incubated with 14C‐testosterone for 24 h in brain heart infusion (BHI) broth. Similar incubations were also carried out with strains of A. actinomycetemcomitans, P. Intermedius and P. gingivalis to study the metabolism of radiolabelled testosterone by these periodontal pathogens. At the end of a 24 h incubation period with fibroblasts and supernatants or sonicates, the radioactive metabolites were extracted with ethyl acetate, evaporated and subjected to thin layer chromatography. The separated metabolites were quantified by scanning the radioactive plates using a Berthold linear analyser. When three sub‐gingival plaque samples were incubated with radiolabelled testosterone there were 50‐fold. 10–12‐fold and 15–17‐fold increases in 5α‐dihydrotestosterone (DHT) synthesis over 4‐androstenedione production in these mixed microbial cultures. The two strains of P. intermedius produced 3‐ and 20‐fold increases in 4‐androstenedione production and DHT synthesis respectively. Both strains of A. actinomycetemcomitans and P. gingivalis showed 3–4‐fold and 12–28‐fold increases respectively in 4‐androstenedione synthesis over that of DHT. Culture supernatants of P. intermedius and P. gingivalis caused 3‐fold and 2‐fold increases in DHT synthesis by fibroblasts over controls. There was little change in the case of the third pathogen. Since DHT has implications on matrix synthesis by fibroblasts in the environment of plaque associated inflammatory periodontal disease, bacterial metabolism and the effect of bacterial supernatants on human gingival fibroblasts can influence the degree of inflammatory repair.
Effects of FMLP and LPS on [Ca2+]i of peritoneal exudate polymorphonuclear leukocytes following onset of inflammation
Authors: Qu J. , Hosoi K. , Shimojima T. , Oi T. , Lkeda K.
Published: July 2006

Because a general study of activated neutrophils may have relevance to periodontal diseases and accompanying inflammation, we studied a function of mouse polymorphonuclear leukocytes (PMNs) that exude into the peritoneal cavity in response to inflammation caused by i.p. injection of 2% casein. The effects of E. coli‐lipopolysaccharide (E‐LPS) and a chemotactic factor, N‐for‐myl‐N‐methionyl‐N‐leucyl‐L‐phenylalanine (FMLP), on the level of intracellular calcium ([Ca2+]i) in these PMNs were examined. From analysis made with a laser cytometer (ACAS 570), the PMNs in exudates harvested 3–9 h after the onset of inflammation were shown to undergo [Ca2+]i elevation in response to 10–6 M FMLP. The peak concentration of [Ca2+]i elicited by FMLP was highest in exudate cells 6 h after casein injection. In addition, about 65% of the PMNs in the 3‐h exudate were FMLP sensitive displaying an elevated [Ca2+]i, whereas more than 85% of them in 6‐ and 9‐h exudates became FMLP sensitive. Also, the maximum level of [Ca2+]i after FMLP stimulation was potentiated by pretreatment of the cells with E‐LPS (0.2 μg/ml). The present study suggests that PMNs induced by casein injection and appearing in mouse peritoneal exudate at different times possess significantly different ability to undergo [Ca2+]i elevation, and different susceptibility toward a chemotactic factor, FMLP.
Effects and interactions of tumour necrosis factor α and bradykinin on interleukin‐1 production in gingival fibroblasts
Authors: Yucel‐Lindberg T. , Lerner U.H. , Modéer T.
Published: July 2006

Effects of and interactions between tumour necrosis factor α (TNFα) and bradykinin (BK) on production of interleukin‐1 (IL‐lα, IL‐lβ) in human gingival fibroblasts were studied. The cytokine TNFα induced production of cell‐associated IL‐lα and IL‐1β in gingival fibroblasts, with IL‐lβ being most abundant. Addition of BK, in the presence of TNFα, for 1 h and 6 h, respectively, synergistically enhanced the TNFα induced IL‐lβ production, whereas BK alone did not induce 1L‐1 production. Similar to BK, two phorbol esters, phorbol 12,13 dibutyrate (PDBu) and phorbol 12‐myristate‐13‐acetate (PMA) which are known to stimulate protein kinase C (PKC), synergistically enhanced the TNFα induced IL‐lβ production in the gingival fibroblasts. On the contrary, a phorbol ester which does not activate protein kinase C, 13‐phorbolacetate (13‐PA), did not potentiate the TNFα induced IL‐lβ production. Similar to BK, the phorbol esters (PMA, PDBu, 13‐PA) alone did not induce IL‐1β production in the gingival fibroblasts. The results indicate that TNFα induces production of cell‐associated IL‐1 in gingival fibroblasts, which can be upregulated by a PKC dependent pathway.
Migration and proliferation of progenitor cells in the connective tissue of rat gingival papilla
Authors: Pender N. , Heaney T.G.
Published: July 2006

The aim of this investigation was to determine whether gingival fibroblast progenitor cells undergo division and whether there is evidence of migration of their progeny from the paravascular sites within the interdental gingival septum (IGS). 30 male hooded Lister rats aged 6 weeks, were killed in groups of ten, 3, 75 and 171 h after a single injection of tritiated thymidine. Autoradiographs were examined of transverse Historesin sections of the papilla between second and third mandibular molars in 29 specimens, taken from equidistant intervals between the col and alveolar bone crest. Median grain counts in the whole papilla were greatest within 10 μm of blood vessels at 3 h (p<0.02) and decreased throughout the papilla with time (p<0.0001). The median grain counts at level 5, nearest the periodontal ligament, were greatest at all times (p<0.01). The distance of labelled nuclei from blood vessel walls increased with time, most notably at level 5 (p<0.001). The mean Clustering Index increased (p<0.01) from 4.6% at 3 h to 12.3% and 11.6% at 75 h and 171 h respectively. At 75 h, the median grain count of clustered nuclei was smaller (p<0.01) than that of non‐clustered nuclei. These data are consistent with the occurrence of clonal division and migration within the IGS and the presence of a slowly cycling cell population near to the periodontal ligament.
A feasibility study on the use of direct light silver stain compared with dark field microscopy for differential counting of subgingival plaque
Authors: Coffey A. , Coulter W. A. , Linden G.J.
Published: July 2006

The purpose of the present study was to compare direct light microscopy using a silver stain, with dark field microscopy for differential counting of subgingival plaque samples from patients with periodontitis. The feasibility of using the staining method was assessed on subgingival plaque samples which were collected at 34 sites from patients with untreated adult periodontitis. Differential counts of plaque morphotypes assessed by both methods showed close agreement. The proportions of spirochaetes assessed by both methods were significantly associated with probing depth. The silver stain proved a simple, rapid and inexpensive method for differential counting of plaque composition. This method is suitable for possible use in general dental practice where smears could be made at the chair‐side and allowed to dry ready for staining and counting at the dentist's convenience using a simple light microscope. A permanent record is also produced which could allow for comparison of samples from before and after treatment and could be used as an aid to patient motivation in suitable cases.
Laminin and collagen IV distribution and ultrastructure of the basement membrane of the gingiva of the rat incisor
Authors: Graner E. , Line S.R.P. , Jorge J. , Lopes M.A. , Almeida O.P.
Published: July 2006

The continuous growth of the rat incisor is associated with renovation of the junctional epithelium and resorption of the periodontal ligament. The circumdental papilla separates the connective tissue suffering resorption from the rest of the gingiva. Laminin and collagen IV were detected by the immunoperoxidase technique on the basement membrane of all regions of the gingival epithelium of the rat incisor, except the internal basal lamina and the internal surface of the circumdental papilla. The internal basal lamina is formed by a granular electron‐dense material, without the organization of a typical basal lamina. Areas of the internal surface of the circumdental papilla, negative for laminin and collagen IV, lack the basal lamina. These data suggest that these molecules are not components of the dento‐epithelial junction of the distal surface of the rat incisor. In addition, the basal lamina is absent or fragmented on the internal surface of the circumdental papilla, adjacent to the areas of the connective tissue undergoing resorption.
Differential reactivity of anti‐E‐selectin monoclonal antibodies in human gingival tissue
Authors: Pietrzak E.R. , Savage N.W. , Xu L.J.
Published: July 2006

E‐selectin is a cytokine‐inducible endothelial glycoprotein which participates in the binding of leukocytes to vascular endothelium. Variable levels of expression of E‐selectin have been reported in gingivitis and periodontitis, and two differing concepts of its significance have emerged: either gingival blood vessels express E‐selectin constitutively, or are continuously activated by inflammatory mediators arising from the gingival environment. A range of monoclonal antibodies reacting with different epitopes of E‐selectin are available commercially. The present study explored the possibility that the choice of antibody could affect estimation of the level of expression of E‐selectin in vivo. Five monoclonal antibodies were used to investigate E‐selectin expression in serial cryosections of human gingival tissue. While E‐selectin‐positive vascular endothelial cells were detected with all antibodies, the number of positively staining endothelial cells varied, with BBAl>H4/18 = H18/7=4D10>1.2B6. The frequency of strong staining in tissue specimens was BBAl>4D10>H4/18=H18/7>1.2B6, while the frequency of weak staining showed the reverse trend. Additionally, with antibodies HI8/7 and 1.2B6, 17 and 36% of the specimens were E‐selectin negative. The occurrence of what appear to be false positives and false negatives confounds estimation of the level of E‐selectin expression. Based on these findings, patterns of endothelial E‐selectin expression in gingivitis and periodontitis should be re‐evaluated.
ICAM‐1‐expressing pocket epithelium, LFA‐1‐expressing T cells in gingival tissue and gingival crevicular fluid as features characterizing inflammatory cell invasion and exudation in adult periodontitis
Authors: Takeuchi Y. , Sakurai K. , Ike I. , Yoshie H. , Kawasaki K. , Hara K.
Published: July 2006

Activated T lymphocytes constitute a major component of inflammatory cells in the early periodontal lesion, and also appear in the gingival crevicular fluid. In an attempt to clarify the relationship between the ICAM‐1 (CD54) expression of pocket epithelium in gingiva and the infiltrating lymphocyte population, we carried out an analysis of CD11a+ (LFA‐lα), CD25+ (IL‐2Rα) and CD4+ (Th) cells subjacent to ICAM‐1‐expressing pocket epithelia and CD11a+ CD25+CD4+ cells in gingival crevicular fluid (GCF). GCF was collected by crevicular washing from 16 patients with periodontitis (P group) and 3 subjects with healthy gingiva (H group). Peripheral blood (PB) was collected at the same time. Mononuclear cells were isolated by Ficoll‐paque gradient centrifugation from GCF and PB. Monoclonal antibodies (mAb) to CD11a, CD25, and CD4 were used for three‐color flow cytometry. Gingival biopsies were obtained from 7 patients in P group and 3 subjects in H group. Serial cryostat sections (6 μm in thickness) were prepared from each biopsy, on which a double staining was performed. The number of CD11a+ CD25+ CD4+ cells and the fluorescence intensity of FITC conjugated anti‐CD 11a were significantly higher in GCF than in PB (p≤0.001 to p≤0.01). CD11a+ CD25+CD4+ cells were not detected in GCF in H group. The pocket epithelia expressed CD54 in P group, but not in H group. The number of CD11a+, CD25+ and CD4+cells infiltrating the connective tissue subjacent to the upper, middle and lower parts of the CD54 positive pocket epithelium (n=16) was 141±26, 38±13, 144±29 (cells/0.04 mm2), respectively, whereas in the CD54 negative pocket epithelium, it was (n=5) 9±2, 3±1, 8±3. In P group, the CD11a+CD25+CD4+cell number in GCF correlated with CD25+, CD11a+cells in the connective tissue subjacent to the CD54+pocket epithelium. These results indicate that expression of ICAM‐1 in pocket epithelium is relevant to the migration of CD11a, CD25, CD4 positive cells in connective tissue subjacent to the pocket epithelium into the periodontal pocket. Assessing the relationship of our findings and other adhesion molecules would offer important clues to the understanding of T cell migration in affected gingiva.
Effect of venous stasis and hypoproteinemia in gingival fluid formation in rats
Authors: Aarli V. , Heyeraas K.J.
Published: July 2006

Experiments were performed to provide information on the mechanisms of the formation of gingival fluid in rats and on the determinants of its flow and composition. For this purpose we studied the effect of increasing net capillary filtration by venous stasis induced by multiple ligations of the jugular vein or by hypoproteinemia induced through puromycine nephrosis. A 1 μl glass capillary was placed in the sulcus of the first maxillary molar for collection of gingival fluid (GF). Colloid osmotic pressure (COP) was determined in GF, in wick fluid from attached gingiva and buccal mucosa, and in plasma. Interstitial fluid hydrostatic pressure (Pi) was measured by micropuncture technique and the fractional removal rate of radiolabelled human serum albumin (kAlb) was recorded in attached gingiva and buccal mucosa. During venous stasis the gingival fluid flow increased from 1.7 μ1/h to 3.8 μ1/h, whereas COPGF fell from 14.1 mmHg to 8.8 mmHg. COP in wick fluid from gingiva was reduced from 10.3 to 4.3 mmHg. Pi increased from 6.8 to 13.1 mmHg, and kAlb in sham‐operated controls increased from 0.068 to 0.189 h‐1. In buccal mucosa COPi was significantly decreased to 7.1 mmHg in rats with venous stasis, whereas Pi and kAlb remained unchanged compared to the sham‐operated controls. In hypoproteinemic rats COPGF was 5.0 mmHg and COPp was reduced from 18.9 to 8.0 mmHg. COPi declined from 8.9 mmHg to 2.4 mmHg in gingiva and from 8.1 mmHg to 2.7 mmHg in buccal mucosa. Pi in attached gingiva increased from 6.1 mmHg to 9.0 mmHg, whereas Pi in buccal mucosa showed no consistent change. The production of gingival fluid was increased about 3 times. We conclude that increased gingival fluid flow during venous stasis and hypoproteinemia is caused by increased capillary filtration, resulting in increased interstitital fluid volume and pressure.
Histological study of lectin binding in regenerated rat junctional epithelium
Authors: Abe Y. , Hara Y. , Kato I.
Published: July 2006

We investigated the expression of carbohydrate residues in regenerated junctional epithelium (JE) cells histopathologically with lectin staining to clarify the mechanisms responsible for the changes in their expression in JE cells derived from residual oral epithelium. Curettage and root planing procedures were performed on the buccal gingival sulci of rat first lower molars, and JE and connective tissues were completely removed. The mandibles were resected after 12 h and 1, 2, 3, 4, 5, 7, 10 and 14 days, fixed with paraformaldehyde, decalcified with EDTA and embedded in paraffin. Serial sections were stained histochemically with four kinds of lectins (PNA, DBA, GS I, UEA I) to clarify the expression patterns of carbohydrate residues in regenerating epithelium. No binding of PNA or DBA was observed even when the regenerating epithelium was attached to the root surface, and they showed the same negative reactions as the basal cells of oral gingival epithelium (OGE). Positive reactions were, however, observed on the more stratified regenerating epithelium along the root surface. Positive reactions with GS I and negative reactions with UEA I were observed throughout the regeneration process, and these were the same as those observed in the basal cells of OGE. Therefore, we concluded that the basal cells and regenerated epithelium derived from OGE expressed the same carbohydrate residues. Futher‐more, the expression of carbohydrate residues, one of the characteristics of JE, was related not only to the attachment to the tooth surface but also to changes of cell shape and cytoskeleton with stratification along the root surface.