bluuebunny/crossref_metadata_2025 huggingface dataset:
A cytochemical study of dense granules in the rat junctional epithelium
Authors: Shimono Masaki , Inoue Takashi , Hamada Yoshinobu , Abiko Yoshihiro , Hsshlmoto Sadamltsu
Published: July 2006

To clarify the details of inlracyloplasmic granules in the junctional epithelium (JEI of the rat gingwo, phosphotungstlc acid (PTA) staining. acid phosphatase cytochemistry and zmc iodide‐osmium (ZIO) staining were carried out. Con‐densing granules containing homogeneous electron‐dense materials. measuring ahout 260 nm in diameter. have hren ohserved at Ihe peripheral cytoplasm 01 the IE. These granules reveal PTA‐positive. ZIO‐positive and acid phosphatase‐positive staining. These results mduate that the granulrs contain glycoprolem phospholipid, lipoprotein and I~sosomal enzymes. From their composmon and morphology, it is suggested that these granules m the IE may conrrihute se‐cretory function and secrete glycoprotems or glycohpids. Although it is unclear whether the dense granules correspond LO membrane‐coating granules hy our stainmg methods. II 1s surmised that, if the dense granules can engage in eatabhsh‐merit of the barrier functmn, then this role is impeded by the large mtercsllular space in the JE.
Gingival hyperplasia in rats induced by oxodipine ‐ a calcium channel blocker
Authors: Nyska Abraham , Waner Trevor , Pirak Michael , Galiano Alvaro , Zlotogorski Abraham
Published: July 2006

Oxodipine, a new calcium channel blocker, induced gingival hyperplasia in rats. This is the first time that a calcium channel blocker has been documented as resulting in gingival hyperplasia in rats. In contrast to diphenylhydantoin, the hyperplastic changes induced by oxodipine were not precipitated by any prior irritation. The histology consisted of purely fibroblastic proliferation without infiltrate of inflammatory cells.
Hemoglobin concentration and oxygen saturation of clinically healthy and inflamed gingiva in human subjects
Authors: Hanioka T. , Shizukuishi S. , Tsunemitsu A.
Published: July 2006

The hemoglobin concentration (Hb index) and oxygen saturation (apparent SO2) in human gingiva were estimated by tissue reflectance spectrophotometry (TRS). The gingiva had significantly lower Hb index and higher apparent SO2 than those in alveolar mucosa, but there was no difference in either parameter among different gingival areas. The reproducibility in repeated measurements was high for both Hb index and apparent SO2 in gingiva. In inflamed gingiva, Hb index was significantly higher than that in clinically healthy gingiva. A lower apparent SO2 was observed in inflamed gingiva. This suggests that the increase in blood supply is insufficient to meet the oxygen demand in inflamed gingiva. There were significant correlations between either the Hb index or the apparent SO2 and the clinical parameters of gingival inflammation such as gingival index, plaque index, Periotron score and probing depth. Thus, TRS may be clinically available to estimate the blood volume and oxygen saturation in inflamed gingiva.
DNA homologies shared among E. corrodens isolates and other corroding bacilli from the oral cavity
Authors: Chen C.‐K. Casey , Potts Thomas V. , Wilson Mark E.
Published: July 2006

In a previous microbiological study of Eikenella corrodens, we noted the presence of E. corrodens strains with variability in colony morphology, as well as other corroding bacilli phenotypically similar to E. corrodens but which were unidentifiable on the basis of biochemical reactions. This raised questions as to whether E. corrodens constitutes a genetically heterogeneous group of organisms, and whether the unidentified corroding bacilli represent atypical E. corrodens or genetically unrelated organisms. In the present study, the genetic relationship among 14 E. corrodens isolates and 6 unidentified corroding bacilli was examined. DNA base compositions were determined from the melting temperatures of DNA samples. DNA homologies among E. corrodens and corroding bacilli were determined by DNA hybridization in solution using S1 nuclease. The % G + C content of E. corrodens strains varied from 56 to 58%, and from 56 to 60% for unidentified corroding bacilli. The DNA homologies among 12 E. corrodens isolates and 2 reference strains varied from 57 to 97%. Although these E. corrodens isolates exhibited variabilities in colony morphology and biochemical profile, no subspecies was identified. The unidentified corroding bacilli shared less than 33% homology with either of the E. corrodens reference strains. These corroding bacilli were further divided into 3 species on the basis of DNA hybridization studies using radiolabeled DNA from 2 representative corroding bacilli. One of the unidentified corroding bacilli appears to be a component of the normal flora in the human oral cavity. Our results indicate that E. corrodens is a genetically homogeneous species containing no recognizable subspecies. However, the oral microflora of periodontally healthy and diseased subjects contains other corroding bacilli which are recovered on media considered selective for E. corrodens. These organisms are morphologically and biochemically similar to E. corrodens but are genetically distinct. Such organisms are found frequently in the human oral cavity and may be easily confused with E. corrodens.
Zero‐order delivery with periodontal placement of tetracycline‐loaded ethylene vinyl acetate fibers
Authors: Tonetti M. , Cugini M. A. , Goodson J. M.
Published: July 2006

The concentration of tetracycline in the gingival fluid was measured in the periodontal pocket following placement of controlled drug delivery monolithic fibers and subgingival irrigation. Following subgingival irrigation with 1% and 10% tetracycline HC1 solution, concentrations decayed exponentially with half times of 4.2 and 12.2 h, respectively. Tetracycline fibers maintained a constant average concentration of 1590 μg/ml in periodontal pockets over a 10‐day period. The observed concentrations were in agreement with those expected from a steady‐state model based on release rate characteristic of the fibers and gingival fluid flow rate. After removal of the delivery system, tetracycline concentrations decreased exponentially with half time of 4.5 h. These data describe the delivery characteristics of tetracycline‐loaded ethylene vinyl acetate fibers as zero‐order for 10 d; following removal, an exponential washout was observed.
Neutrophil‐mediated damage to human periodontal ligament‐derived fibroblasts: Role of lipopolysaccharide
Authors: Deguchi Shinji , Hori Toshio , Creamer Howard , Gabler Walter
Published: July 2006

Human periodontal ligament‐derived fibroblasts (HPLF) were grown to confluency in culture and were subjected to various combinations of neutrophils (PMNs), lipopolysaccharide (LPS) and the chemoattractant formylmethionyl‐leucyl‐phenylalanine (FMLP). After treatment, the cells were stained to distinguish between normal and damaged cells. The stain also allowed an estimation of PMN adherence to the HPLF monolayer. We report that FMLP, LPS or PMNs alone did not damage HPLF cells, nor did PMNs when combined with LPS or FMLP separately. However, PMNs subjected to combinations of LPS (10‐1000 ng/ml) and FMLP (10−9‐10−6 M) caused significant PMN‐mediated fibroblast damage. LPS concentrations greater than 1000 ng/ml inhibited the cytotoxic reaction. Furthermore, we found that FMLP alone did not significantly enhance PMN adherence to the HPLF monolayer but that LPS increased PMN adherence 3‐fold and the combination of LPS and FMLP enhanced adherence 6‐fold. We conclude that LPS promotes PMN adherence to fibroblasts and that such adherence appears to be a crucial, but insufficient stimulus, for the induction of PMN‐mediated HPLF injury.
Low‐dose doxycycline therapy: Effect on gingival and crevicular fluid collagenase activity in humans
Authors: Golub L. M. , Ciancio S. , Ramamurthy N. S. , Leung M. , McNamara T. F.
Published: July 2006

Tetracyclines are now recognized to have non‐antimicrobial properties with therapeutic potential ‐ for example, these agents can inhibit pathologic collagenolysis by blocking mammalian collagenases and other matrix‐degrading metal‐loproteinases. In the current study, adult human subjects with moderate chronic periodontitis were administered specially formulated capsules of doxycycline, containing lower‐than‐usual amounts of this semisynthetic tetracycline, on a daily basis for 2 weeks prior to a full‐thickness flap procedure; control subjects were administered placebo capsules. The gingiva excised during this surgical procedure were extracted, the extracts partially purified and analyzed for collagenase activity using [3H‐methyl] collagen as substrate and the techniques of SDS‐PAGE/fluorography or liquid scintillation spectrometry. In the absence of any drug pre‐treatment, or after a 2‐wk regimen of placebo capsules, the gingival extracts exhibited pathologically‐excessive mammalian collagenase activity. The 2‐wk regimen of low‐dose doxycycline capsules reduced this activity by approximately 60–80% (p < 0.05 and < 0.01, respectively); in vitro exposure of the gingival extract to doxycycline also inhibited its collagenase activity. Collagenase activity in the crevicular fluid of periodontal pockets of an additional group of subjects was also significantly reduced, as was the severity of inflammation at the same gingival sites. The results suggest that a regimen of low‐dose doxycycline capsules may provide a safe (other studies indicate that this regimen may not induce tetracycline resistance in the subgingival plaque) and effective adjunct to instrumentation therapy in the management of pathologic collagenolysis in the periodontal patient. However, further studies are necessary to confirm this hypothesis.
Bradykinin‐2 receptor‐mediated release of 3H‐arachidonic acid and formation of prostaglandin E2 in human gingival fibroblasts
Authors: Modéer T. , Ljunggren Ö. , Lerner U. H.
Published: July 2006

Bradykinin stimulated production of prostaglandin E2 (PGE2) and the release of 3H‐arachidonic acid by gingival fibroblasts in a time‐ and dose‐dependent manner. The effect on PGE2 biosynthesis was seen already after 15 seconds and was maximal after 5 minutes. Several structurally unrelated inhibitors of arachidonic acid metabolism via the cyclooxygenase pathway totally abolished the PGE2 response to bradykinin. The stimulation of PGE2 formation was seen at and above 10 nmol/1 of bradykinin. Des‐Arg9‐bradykinin was 100‐fold less potent compared to bradykinin. Des‐Arg9‐Leu8‐bradykinin did not antagonize bradykinin‐induced PGE2 formation. Met‐Lys‐bradykinin and Lys‐bradykinin also enhanced PGE2 formation in gingival fibroblasts. The stimulatory action of bradykinin on 3H‐arachidonic acid release was observed after 30 s and progressively increased for at least 15 min. The stimulatory effect on3H‐arachidonic acid release by bradykinin was seen at and above 10 nmol/1, whereas des‐Arg9‐bradykinin was without effect up to a concentration of 1 μmol/1. Indomethacin did not affect bradykinin‐induced 3H‐arachidonic acid release. These data show that bradykinin, via a B2‐receptor‐mediated pathway, can stimulate arachidonic acid release and subsequent prostanoid formation in gingival fibroblasts. Consequently, gingival fibroblasts may contribute, by a bradykinin‐regulated reaction, to the enhanced amounts of prostanoids found in gingival tissues and crevicular fluids in patients with periodontal diseases.
Interaction of Fusobacterium nucleatum 191 with human peripheral blood lymphocytes
Authors: Tuttle Raymond S. , Mangan Dennis F.
Published: July 2006

Fusobacterium nucleatum zis frequently isolated in high numbers from the subgingival plaque of patients with periodontal diseases. Adherence of these bacteria to several host tissues is lectin‐like in that it is inhibited by galactose, lactose, and N‐acetyl‐galactosamine. Since F. nucleatum has the capacity to activate human peripheral blood lymphocytes, the purpose of this study was to determine whether F. nucleatum adheres to lymphocytes and, if so, to determine whether lectin‐like interactions facilitate lymphocyte activation. Adherence of F. nucleatum strain 191 to lymphocytes was confirmed by agglutination assays, scanning electron microscopy, and by using fluorescein‐ or [3H]‐labeled bacteria. Saturation of adherence was reached at about 35 bacteria per lymphocyte. F. nucleatum adhered to > 90% of the lymphocytes, and adhered in higher numbers to B cell‐enriched subpopulations than to T cell‐enriched subpopulations. Adherence was inhibited by N‐acetyl‐galactosamine, lactose > galactose, alpha‐ and beta‐methyl galactoside, but not by 100 mM glucose, mannose, N‐acetyl‐glucosamine, or other sugars tested. Lymphocytes underwent mitogenesis when preincubated with bacteria and washed to remove weakly adherent and non‐adherent bacteria. Mitogenesis induced by low concentrations of F. nucleatum was reduced, but not completely eliminated, by N‐acetyl‐galactosamine. However, N‐acetyl‐galactosamine had no effect on mitogenesis induced by preincubation with high concentrations of bacteria. These results suggest that adherence of F. nucleatum facilitates activation of lymphocytes, particularly at low concentrations of bacteria.
Possible role of cementoblasts in the resorbant organ of human deciduous teeth during root resorption
Authors: Sasaki Takahisa , Watanabe Chiaki , Shimizu Teruo , Debari Kazuhiro , Segawa Kazuyuki
Published: July 2006

Human deciduous teeth undergoing physiologic root resorption were extracted and fixed with a mixture of formaldehyde and glutaraldehyde and processed for scanning (SEM) and transmission (TEM) electron microscopy, and for acid (ACPase) and alkaline phosphatase (ALPase) cytochemistry. The resorbant organ, rich in odontoclasts, cementoblasts, fibroblasts, and macrophages, formed prominent resorption lacunae in root dentin. SEM observations of resorption lacunae treated with trypsin solution showed islands of newly‐formed cementum matrix in part of the resorbing dentin surfaces. Such cementum consisted of bundles of densely‐arranged collagen fibrils and, in part, contained forming cementocytic lacunae and canaliculi. Active cementoblasts adjacent to odontoclasts on resorbing dentin surfaces showed cuboidal outlines and were characterized by the presence of numerous cisterns of rough endoplasmic reticulum, well‐developed Golgi complexes, secretion granules, and many mitochondria. They sometimes formed a thin layer of cementoid and/or cementum matrix upon the resorbing dentin surface. These cementoblasts had ACPase‐positive lysosomes in the cell bodies and exhibited intense ALPase activity along the plasma membranes of whole cell surfaces. These results suggest that, during root resorption, 1) active cementoblasts are present adjacent to active odontoclasts and 2) these cementoblasts are involved in remodeling the resorbing dentin surfaces.
Selective modulation of bacterial attachment to oral epithelial cells by enzyme activities associated with poor oral hygiene
Authors: Childs W. C. , Gibbons R. J.
Published: July 2006

The present investigation explored the hypothesis that elevated levels of certain enzymes in the gingival crevicular environment of individuals with poor oral hygiene and/or gingival inflammation may modify the surfaces of epithelial cells and thereby modulate the types of bacteria which attach and colonize. Buccal epithelial cells treated with neuraminidase and certain proteases were used as a model for study. Bacteria studied included Streptococcus sanguis and Streptococcus mitis which have been associated with gingival health, Actinomyces species which are increased in plaque associated with developing gingivitis, and Bacteroides gingivalis, Bacteraides intermedius, and Actinobacillus actinomy‐cetemcomitans which are associated with destructive periodontal diseases. Treatment of epithelial cells with the enzymes studied produced selective effects on their receptivity for bacteria. Neuraminidase treatment of epithelial cells greatly reduced the attachment of all strains of S. sanguis and S. mitis studied. In contrast, the number of Actinomyces viscosus, A. naeslundii and A. israelii cells which attached was significantly increased. Neuraminidase treatment also appeared to enhance attachment of B. intermedius and B. gingivalis. Treatment of buccal cells with trypsin, chymotrypsin or papain also selectively affected bacterial attachment. Such protease treatment greatly reduced the numbers of streptococci and A. viscosus cells which attached, while the numbers of B. gingivalis and B. intermedius were significantly increased. Treatment of epithelial cells with preparations of lysosomal enzymes derived from human PMNs produced similar selective effects. The changes in bacterial adhesion observed by the enzyme treatments studied are consistent with the shifts in the composition of the gingival crevice flora which occur when oral hygiene is terminated and gingivitis develops.
The protein composition of gingival crevicular fluid sampled from male adolescents with no destructive periodontitis: Baseline data of a longitudinal study
Authors: Curtis M. A. , Sterne J. A. C. , Price S. J. , Griffiths G. S. , Coulthurst S. K. , Wilton J. M. A. , Johnson N. W.
Published: July 2006

Gingival crevicular fluid (GCF) is a promising source for markers of destructive periodontal diseases activity. As the initial stage of a longitudinal study into the characterization of disease markers, GCF sampled from 104 sites in 74 adolescents was examined via sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS/PAGE). In this population, which had varying degrees of gingivitis but little evidence of destructive periodontitis, there was a highly homologous GCF protein profile. The plasma components, albumin, transferrin and IgG, were major constituents of all samples. In addition, a second group of non‐plasma derived proteins, with molecular weights 37 kDa, 47 kDa, 57 kDa and 59 kDa, was also commonly detected. The high frequency of occurrence of these components suggests that they may represent products of normal turnover of the periodontal tissues. Analysis of GCF sampled from patients with progressing destructive disease revealed a different SDS/PAGE profile particularly with respect to proteins of non‐plasma origin. It is anticipated that the major metabolic changes which accompany the destruction of the tissues during future disease episodes in the adolescent study population will be discernible as alterations to the GCF protein profile.
Relationship between levels of aspartate aminotransferase in gingival crevicularfluid and gingival inflammation
Authors: Persson G. Rutger , DeRouen Timothy A. , Page Roy C.
Published: July 2006

Data from several sources demonstrate that disease‐active and disease‐inactive periodontal pockets exist, but currently available diagnostic procedures do not permit identification of disease‐active sites at any given point in time. Using the experimental gingivitis model, we have performed studies aimed at determining whether levels of the enzyme aspartate aminotransferase (AST) in gingival crevicular fluid correlate with the presence and extent of periodontal inflammation. Gingival inflammation was assessed using the Gingival Index and the Sulcular Bleeding Index, and enzyme activity was measured using a Standard procedure. Our data reveal a statistically significant association between AST values and Gingival Index scores for spontaneously occurring lesions (p < 0.02–0.04) and experimentally induced lesions (p < 0.0001), as well as the extent of change in these values during developing experimental gingivitis (p < 0.0001) and resolving experimental gingivitis (p < 0.0001). The data demonstrate that AST levels can be used to assess the presence and extent of periodontal inflammation.
Prepubertal periodontitis: a review of diagnostic criteria, pathogenesis, and differential diagnosis
Authors: Watanabeb Keiko
Published: July 2006

This paper reviews the literature on prepubertal periodontitis (PP) according to the definition and the classification of PP by Page. The generalized form of PP (G‐PP) defined by Page was identified as the oral manifestation of a systemic disease called leukocyte adhesion deficiency (LAD) and thus the pathogenesis is known at the molecular level. On the other hand, the localized form of PP (L‐PP) is a disease defined by clinical criteria and its pathogenesis is not known at the molecular level. The reported prevalence of L‐PP differs widely in reports, according to the methodology and population studied. However, it seems to be at least 0.84% or greater. Potential periodontal pathogens that have been associated with L‐PP include the following bacteria: Acti1nobacillus actinomycetemcomitans (A.a.), Bacteroides intermedius, Bacteroides gingivalis, Capnocytophaga sputigena, and Eikenella corrodens. Suggested contributing factors have included PMN or monocyte chemotactic defects and cementum defects. There is no unique pattern of bone loss in L‐PP; however, there may be a type of periodontitis that affects all deciduous teeth, in the absence of LAD. L‐PP may lead to localized juvenile periodontitis (LJP) or generalized juvenile periodontitis (GJP). Histiocytosis X, hypophosphatasia and mild forms of blood dyscrasias may have minimal or no clinical signs and symptoms except for alveolar bone loss. Therefore diseases known to be associated with alveolar bone loss must be definitively excluded in prepubertal children until the pathogenesis of L‐PP at the cellular and molecular levels is understood and L‐PP can be definitively diagnosed either as a distinct disease entity or entities.
The plasma cell at the advancing front of the lesion in chronic periodontitis
Authors: Joachim F. , Barber P. , Newman H. N. , Osborn J.
Published: July 2006

This study analyses the infrastructure of the plasma cell population of periodontitis‐affected soft tissue close to the advancing front of interdental lesions. Biopsies from 20 patients and 3 control volunteers were examined: 5 with treated adult periodontitis (AP), 5 with untreated AP, 5 with treated juvenile or postjuvenile periodontitis (JP) and 5 with untreated JP. Plasma cell (PC) counts increased significantly (p < 0.05) with lesion severity. They were absent from epithelium and sparse in the clinically healthy control specimens. Degenerate PC tended to be more numerous within JP tissue but differences were not significant (p > 0.05) when compared to AP. Intact plasma cells were never seen within JP superficial connective tissue. Russell bodies were small and few in number. The presence of degenerated plasma cells indicated normal formation and release of immunoglobulins within the tissues of AP and JP. Increased counts of degenerate PC and tissue destruction in JP suggested a correlation, possibly attributable to anti‐collagen antibody secretion.
Cell attachment activity of cementum: bone sialoprotein _ identified in cementum
Authors: Somerman M. J. , Sauk J. J. , Foster R. A. , Norris K. , Dickerson K. , Argraves W. S.
Published: July 2006

Considerable research effort has been directed at preparing root surfaces in a fashion that would promote cell attachment leading to periodontal regeneration; however, no methods have proven to be clinically predictable. Identification of attachment protein(s) associated with the root surface matrix of cementum may prove valuable for developing effective clinical treatments. In this study cementum proteins were extracted from bovine and human teeth by sequential chaotropic extraction using guanidine followed by guanidine/EDTA. The guanidine/EDTA extract, but not guanidine extract, was found to promote attachment of fibroblasts. This attachment activity was inhibitable with synthetic peptide containing the attachment sequence arginine‐glycine‐aspartic acid (RGD). Fractionation of the guanidine/EDTA extract revealed several fractions with attachment activity. Immunoblot analysis demonstrated that two of these fractions contain the bone‐associated RGD containing attachment protein, bone sialoprotein‐II (BSP‐II). In addition, attachment activity was also noted in other fractions that could not be attributed to BSP‐II or fibronectin. These studies indicate that a component of the attachment activity of cementum is likely to be due to BSP‐II and that cementum contains additional, as yet undetermined, attachment proteins.
A cross‐sectional analysis of aspartate aminotransferase in human gingival crevicular fluid
Authors: Imrey Peter B. , Crawford John M. , Cohen Rhonna L. , Alves Mario E. A.F. , McSwiggin Theresa A. , Chambers Donald A.
Published: July 2006

Previous investigation has shown that the concentration of aspartate aminotransferase (AST), an established serum marker for cardiac and liver damage in humans, is significantly elevated in samples of gingival crevicular fluid (GCF) from ligated teeth in beagle dogs. This paper reports on a cross‐sectional study of the relationships between AST in GCF and clinical indices of human periodontal disease in 60 patients with mild to moderate adult periodontitis. AST standardized to a 30‐second collection interval (AST30) showed substantial (multiple regression R2= 0.61) association with summary indices of patient disease status, modest association (partial R2= 0.22) with tooth disease status within patient, and weaker (partial R2= 0.12) but statistically significant association with site‐to‐site variation in disease at the same tooth. AST concentration showed modest (R2= 0.30) between‐patient relationship with clinical indices, but no clinically significant relationship with these indices between sites within patients, suggesting a rough proportionality between accumulated enzyme and GCF volume at sites with varying stages of disease. The relationship between GCF volume and probing depth also appears central to interpretation of enzyme assays. Clinical measures of past periodontitis and current inflammatory disease are cross‐sectionally related to variation in AST30, across patients and sites within the same patient. Considerable residual variation, especially elevated AST30 in the absence of clear signs of disease, may result from varying levels of current disease activity, not reflected in clinical measures.
The development and structure of principal fibers and cellular cementum in rat molars
Authors: Yamamoto Tsuneyuki , Wakita Minoru
Published: July 2006

The principal fibers and cellular cementum were examined in various developmental stages in rat molars by light and electron microscopy, and their development and structure were studied. The principal fibers increased in thickness with root development. At any given stage, the principal fibers consisted of small fiber bundles on the cementum surface and showed a branching structure. Sharpey's fibers also showed a similar branching structure and increased in thickness, as traced superficially in the cementum. It was suggested that the principal fibers increased in thickness by means of the aggregation of fiber bundles. The development of cellular cementum was divided into two (early and late) phases on the basis of the fiber arrangement. The early cementum was believed to contain a few Sharpey's fibers and many randomly arranged intrinsic fibers. The late cementum contained thicker Sharpey's fibers with branches and the intrinsic fibers which appeared to encircle Sharpey's fibers and/or meander among them.
Role of interleukin‐1 and prostaglandin in in vitro bone resorption induced by Actinobacillus actinomycetemcomitans lipopolysaccharide
Authors: Ishihara Yuichi , Nishihara Tatsuji , Maki Eijiro , Noguchi Toshihide , Koga Toshihiko
Published: July 2006

Lipopolysaccharide (Y4 LPS) isolated from Actinobacillus actinomycetemcomitans strain Y4 induced bone resorption in BALB/c mouse calvaria organ culture. The calcium release from LPS‐low responsive C3H/HeJ mouse calvaria by Y4 LPS was very low. Indomethacin almost completely inhibited prostaglandin E2 (PGE2) production by Y4 LPS‐stimulated BALB/c mouse calvaria, but did not suppress interleukin‐1 (IL‐1) release from the calvaria, and partially suppressed the bone resorption. Dexamethasone strongly inhibited the PGE2 and IL‐1 production by Y4 LPS‐stimulated BALB/c mouse calvaria. as well as Y4 LPS‐induced bone resorption. Dexamethasone inhibited expression of membrane IL‐1 on osteoblastic cells stimulated with Y4 LPS, but indomethacin did not. Furthermore, anti‐IL‐1 serum partially suppressed the calcium release from Y4 LPS‐stimulated BALB/c mouse calvaria. These results suggest that both PGE2 and IL‐1 participate in Y4 LPS‐induced bone resorption in vitro.
Identification of osteoclasts and their mononuclear precursors. A comparative histological and histochemical study in hamster periodontitis
Authors: Baroukh B. , Saffar J. L.
Published: July 2006

Quantification of osteoclast resorption, a good index of periodontitis destruction, is primarily based on osteoclast identification. As their identification is sometimes dubious, we compared osteoclastic counts in hamster specimens processed for either routine histology or tartrate‐resistant acid phosphatase (TRAP) staining. No difference was found between the two approaches concerning the number of osteoclasts. However the mean bone‐osteoclast interface was higher in the TRAP‐stained specimens (+ 30%, p<0.02). As osteoclast precursors are also TRAP+ cells, they were quantified too. Compared with controls, there was a dramatic increase (p < 0.0001) in periodontitis‐affected animals. Precursors were strongly correlated to active osteoclasts (r = 0.97). Our data suggest that precursors are recruited only when the disease is active in a given site.
Expression of EGF‐receptors on epithelial and stromal cells of normal and inflamed gingiva
Authors: Irwin C. R. , Schor S. L. , Ferguson M. W. J.
Published: July 2006

Immunolocalization techniques were used to examine the expression of the cell surface receptors of EGF in normal and inflamed gingival tissue. Detectable levels of receptor were not observed in any (0/6) of the normal tissue biopsies examined; in contrast, the EGF‐receptor was expressed by both epithelial and stromal cells in 7/9 of the inflamed tissue biopsies. Receptor expression by epithelial cells in inflamed tissues exhibited a variable distribution pattern. In the majority of sections, staining was confined to cells in the spinous, granular and cornified cell layers, with little in the basal layer. Occasionally, isolated islands of stained epithelial cells were present, suggesting their clonal origin. Staining for the EGF receptor was also observed in fibroblasts and endothelial cells throughout the lamina propria of inflamed tissue. Positive staining for the receptor ligand (EGF) was observed in both normal and inflamed tissue. These data suggest that an up‐regulation of cell surface receptors for EGF occurs during the inflammatory response, this resulting in an increased cellular responsiveness to EGF.
Urea concentration in minor mucous gland secretions and the effect of salivary film velocity on urea metabolism by Streptococcus vestibularis in an artificial plaque
Authors: Macpherson L. M. D. , Dawes C.
Published: July 2006

Our purpose was to determine the urea concentration in minor mucous gland (MMG) secretions and the pH at proximal and distal aspects of the lower surface of artificial plaque in vitro during infusion of urea solutions over the surface, at different film velocities. Saliva is present in the mouth as a slowly moving film (ca. 0.1 mm thick) with an estimated velocity in the range of 0.8–8.0 mm/min. At low velocities, due to the accumulation of bacterial products, a progressive increase in their concentration may occur in both the plaque and the overlying salivary film at the distal edge (where the film leaves the plaque). S. vestibularis, an oral micro‐organism possessing ureolytic activity, was combined with 1% agarose, to give a urease Vmax similar to that of natural plaque. The artificial plaque was in the chamber (6.0 × 6.0 square and 0.5 or 1.5 mm deep) of a diffusion apparatus, and a urea‐containing artificial saliva (3.3 or 13.2 mmol/ 1) was infused over the surface, as a film 0.1 mm deep, at velocities of 0.8, 8.2 and 86.2 mm/min. At the lower (physiologically normal) urea concentration and the two lower film velocities, most urea appeared to be metabolized at the proximal end of the plaque, which developed a higher pH. At the higher urea concentration, and a film velocity of 8 mm/min, a higher pH was found at the distal end. This was probably due to the combination of greater urea availability and a reduced rate of ammonia loss distally. At a film velocity of 86.2 mm/min, proximal/distal pH gradients did not develop. Thus the salivary film velocity may influence the pH and ammonia level in plaque and perhaps the development of gingivitis. In unstimulated and stimulated MMG secretions, which are the secretions in contact with the buccal surfaces of most teeth, the urea concentrations were 5.27 ± 1.07 and 4.38 ± 1.51 mmol/1, respectively.
Interleukin‐2, interleukin‐2 receptor and interleukin‐4 levels are elevated in the sera of patients with periodontal disease
Authors: McFarlane Christine G. , Meikle Murray C.
Published: July 2006

Three serological markers of immune cell activation, interleukin‐2 (IL‐2), soluble interleukin‐2 receptor (sIL‐2R), and interleukin‐4 (IL‐4), were measured by enzyme‐linked immunosorbent assays in 20 control subjects and 26 periodontitis patients. The experimental group comprised 19 juvenile/post‐juvenile and 7 severe generalized periodontitis patients with radiographic evidence of alveolar bone loss. Although some control sera contained immunoreactive IL‐2 (2 of 20) and IL‐4 (3 of 20), all contained sIL‐2R, the levels of which correlated well with age (r = 0.644). Mean levels of all three markers were significantly elevated in the sera of patients with periodontal disease compared to control values. However, there was a wide variation in the amounts detected; IL‐2 (0.21‐173.33 ng/ml); sIL‐2R (217.95‐1177.27 units/ml); IL‐4 (3.17‐16.35 pg/ ml), which did not correlate with either the degree of bone loss or pocket formation observed clinically. Moreover, there was no correlation between the levels of IL‐2, slL‐2R or IL‐4 for any given individual in the experimental group. The finding that only 2 of the control sera contained IL‐2 (10%) compared to 23 of the periodontitis patients (88.5%) suggests that, of the three parameters investigated, the measurement of IL‐2 could provide a sensitive laboratory test for assessing periodontal disease activity. Nevertheless, a definitive study to determine the relationship of serum IL‐2 levels to clinical parameters of disease activity will be necessary to confirm this observation. These results provide direct evidence for the systemic activation of immune cells in periodontitis, and suggest a role for IL‐2 and IL‐4 in the pathogenesis of the disease.
Bacteriological study of juvenile periodontitis in China
Authors: Han Naiming , Xiao Xiaorong , Zhang Liangsheng , Ri Xinquan , Zhang Juzhi , Tong Yuehua , Yang Meiru , Xiao Zhuoran
Published: July 2006

The predominant cultivable bacteria associated with juvenile periodontitis (JP) in China were studied for the first time. Subgingival plaque samples were taken on paper points from 23 diseased sites in 15 JP patients and from 7 healthy sites in 7 control subjects. Serially diluted plaque samples were plated on nonselective blood agar and on MGB agar, a selective medium for the isolation of Actinobacillus actinomycetemcomitans. Fifteen or more isolated colonies from each sample (in sequence without selection) were purified for identification. The results indicated that the microfiora in healthy sulci of the 7 control subjects was significantly different from that in diseased sites of JP patients. The predominant species in healthy sulci were Streptococcus spp. and Capnocytophaga gingivalis. In JP patients, Eubacterium sp. was found in significantly higher frequency and proportion. Actinobacillus actinomycetemcomitans was not detected in any samples. It appears that this species is not associated with juvenile periodontitis in China.
The regulatory effects of monocytes on human natural killer cells activated by lipopolysaccharides
Authors: Lindemann R. A.
Published: July 2006

Lipopolysaccharides (LPS) rapidly enhance cytotoxicity of human natural killer (N K.) cells against tumor targets. The regulatory effects of peripheral blood monocytes (MO) on this activation were measured. When lymphocytes were kept at a constant number in culture containing LPS from oral and enteric bacteria, increasing the percentage of MO caused a dose‐dependent suppression of NK cytotoxicity. This suppression was reversed by adding the prostaglandin (PG) inhibitor indomethacin which indicates that PGE was released by MO stimulated by LPS. PGE is known to suppress NK activity by its effects on cAMP. MO separated from lymphocytes by transwell membranes also suppressed NK cells in the presence of LPS but this action was again reversed by indomethacin. This suggests that cell‐to‐cell contact is not necessary for MO to suppress NK cytotoxicity when stimulated by LPS. The role of interleukin‐1 (IL‐1) and tumor necrosis factor (TNF) in NK suppression was studied. Antibodies to IL‐1 and TNF did not alter the suppression mediated by MO on NK activity. Adding IL‐1 or TNF to cell cultures without MO or LPS had no effect on NK activity after 24 h. TNF, but not IL‐1, enhanced NK activily in the presence of LPS in cultures without MO. When PGE was pre‐incubated with only lymphocytes for 2 h, the activating effects of a secondary stimulation, interleukin‐2 (IL‐2), were inhibited. IL‐1 had no effect on IL‐2 activation when pre‐incubated with PBL but TNF slightly enhanced IL‐2‐induced NK cytotoxicity.
A re‐evaluation of the distribution of the elastic meshwork within the periodontal ligament of the mouse
Authors: Johnson R. B. , Pylypas S. P.
Published: July 2006

The elastic properties of the periodontal ligament have been attributed, in part, to oxytalan fibers, as no other types of elastic fibers are described there. It has been difficult to study the periodontal elastic meshwork by standard microscopic techniques because it is partially obscured by the adjacent periodontal ligament collagen fibers. Our study employed methods which either completely or partially removed mandibular molar periodontal ligament collagen fibers, exposing a previously undescribed periodontal elastic meshwork. The periodontal elastic meshwork was composed of many elastin lamellae containing both peripheral microfibrils of regular arrangement and central microfibrils of irregular arrangement, which could only be demonstrated in oxidized tissues. Peripheral, regularly arranged bundles of microfibrils resembled oxytalan fibers, which were often adherent to the border of the elastin lamella. Elastin lamellae containing irregular microfibrils resembled elaunin fibers. These fibers probably enclosed either blood vessels, nerves or collagen fiber bundles. Peripheral microfibrils attached elaunin to cementum, alveolar bone, blood vessels, and principal periodontal collagen fibers. Thus, the periodontal elastic meshwork is composed of both oxytalan and elaunin fibers. Microfibrils attach elaunin fibers to the adjacent non‐elastic tissue and also form bundles which traverse the periodontal ligament space and are probably the oxytalan fibers demonstrable by light microscopic techniques. This meshwork of oxytalan and elaunin fibers probably contributes to tooth support and maintenance of periodontal homeostasis by dissipating chewing forces and maintaining patency of periodontal blood vessels.
Numbers and vitality of leukocytes in pocket washings of untreated periodontitis lesions in humans utilizing a novel intracrevicular lavage technique
Authors: Zappa U. , Boretti G. , Graf H. , Case D.
Published: July 2006

The purpose of the present study was to develop an intracrevicular lavage technique, and to use it for assessment of the total number and % of vital leukocytes from untreated periodontitis pockets. A lavage device was developed, consisting of specially crafted cannulas, a vacuum pump and a charge amplifier. In vivo evaluations showed that there was a linear relationship between lavage time and lavage volume; 2–6 lavage samples were obtained from each of 20 patients with untreated advanced periodontitis, and the lavage time was measured in a subsample of 16 pockets. The lavage fluid was centrifuged, and the supernatant was separated from the cellular components. The cells were vital‐stained using two methods, trypanblue exclusion method (TB) and ethidiumbromide fluorescein‐diacetate stain (EB‐FDA). Numbers of vital and non‐vital leukocytes per sample were assessed using a Neubauer chamber. The number of erythrocytes per sample was evaluated using the same counting method. The results included 95 samples obtained from the 20 patients: 76% of all samples ranged in pocket depth between 4 and 8 mm. The lavage technique provided an overall mean lavage volume of 282.37 microliters in an average time of 16.44 seconds. The mean number of leukocytes per sample was 22.20 × 103 (TB) and 24.48 × 103 (EB‐FDA). Percent vital leukocytes were 72.27 (TB) and 72.63 (EB‐FDA). EB‐FDA had a lower counting error than TB. The low erythrocyte counts per sample suggested that subgingival bleeding during sampling was negligible. Spearman correlation coefficients showed weak associations between pocket depth and leukocyte counts, % of vital leukocytes and erythrocytes. Due to the short sampling time this new intracrevicular sampling technique permits sampling of pockets before the tissue responds to the stimulus of the lavage device, and provides subgingival washings with high numbers of leukocytes.
General issues in efficacy, equivalency, and superiority trials: Clinical considerations
Authors: Listgarten Max A.
Published: July 2006

The design of clinical trials aimed at treating different types of periodontal diseases must take into account the prevalence of the disease in the population and the relationship of various descriptors, which may vary from disease to disease. For screening purposes, patients should be selected with disease in the high‐severity range, in order to maximize the likelihood of detecting a therapeutic effect. Subsequent trials may be designed around a more representative group of subjects. Therapies must be evaluated on the basis of actual clinical changes, rather than their effect on presumed etiologic factors. The observed changes must be of clinical as well as statistical significance. The distribution of periodontal diseases within a dentition may affect as few as one or as many as over one hundred sites. Strategies are needed to correlate events observed at sites within the dentition, i.e. tooth surface‐based measurements or scores, with events that are subject‐based, e.g. concentration of blood or salivary components.
Changes in cytokeratin expression during the development of the human oral mucosa
Authors: Pelissier A. , Ouhayoun J. P. , Sawaf M. H. , Forest N.
Published: July 2006

The changes in cytokeratin expression by the developing oral mucosa of 10 to 23‐week‐old human fetuses were studied by indirect immunofluorescence using a panel of 15 monoclonal antibodies. The lining and masticatory mucosae were incompletely differentiated in 10‐wk fetuses, since they expressed identical patterns of cytokeratins (CK 4, 5, 8, 13, 18, 19 and probably CK 14, 16, 17) very similar to that of adult alveolar mucosa. The main difference was the presence of cytokeratins 8, 18 and 19 in embryonic tissues. Cytokeratins 1, 2, 10 and 11 began to appear in gingival and hard palate epithelium from wk 11, predicting the differentiation of the masticatory mucosa by wk 16. The patterns of cytokeratin expression in the 23‐wk fetus in the lining and masticatory mucosae appear to be different. In lining mucosa, the only difference from the 10th wk is a decrease in cytokeratins 8, 18 and 19, whereas the pattern of cytokeratin expression in masticatory mucosa (CK 1, 2, 4, 5, 8, 10. 11, 13, 18, 19 and probably CK 14, 16 and 17) is now very near that of adult gingiva. This pattern appears, as in the adult, to be similar to that of the epidermis in the same period.
Endothelial cell leukocyte adhesion molecule‐1 (ELAM‐1) and intercellular adhesion molecule‐1 (ICAM‐1) expression in gingival tissue during health and experimentally‐induced gingivitis
Authors: Moughal N. A. , Adonogianaki E. , Thornhill M. H. , Kinane D. F.
Published: July 2006

The changes in vascular adhesion molecule expression and numbers of infiltrating leukocytes during a 21‐day experimental gingivitis episode were investigated immunohistochemically. Monoclonal antibodies to ELAM‐l (1.2B6), ICAM‐l (6.5B5), CD3 (OKT3 ‐ pan‐T cell) and neutrophils (PMN‐elastase) were used to identify positive vessels and leukocytes within gingival biopsies taken on d 0, 7, 14 and 21. Vascular endothelium expressed ELAM‐1 and ICAM‐1 both in clinically ‘healthy’ tissue (d 0) and in experimentally inflamed tissue (d 7 to 21). Positive vessels were found mainly in the connective tissue subjacent to the junctional epithelium where the highest numbers of T cells and neutrophils were also seen. Although T cells were found in all tissue areas studied, neutrophils were largely concentrated in the junctional epithelium and the subjacent connective tissue but were absent from the oral epithelial region. As the experimental gingivitis developed, the number of T cells or neutrophils in the different tissue regions did not change significantly although the most intense vascular ICAM‐1 and ELAM‐1 staining redistributed to the CT adjacent to the junctional epithelium. A prominent feature was the intense ICAM‐1‐positive staining of the junctional epithelium and its absence in the closely adjacent oral epithelium, in both clinically ‘healthy’ and inflamed tissue. The gradient of ICAM‐1 in junctional epithelium, with the strongest staining on the crevicular aspect plus the vascular expression of ELAM‐1 and ICAM‐1 in both clinically ‘healthy’ and inflamed tissue may be crucial processes which direct leukocyte migration towards the gingival crevice.
Ultrastructural and ultracytochemical characteristics of multinucleated cells after hydroxyapatite implantation into rat periodontal tissue
Authors: Kawaguchi Hiroyuki , Ogawa Tetsuji , Shirakawa Masaharu , Okamoto Hiroshi , Akisaka Toshitaka
Published: July 2006

Multinucleated cells (MNCs) that appeared after hydroxyapatite (HAP) implantation into experimentally‐produced bone defects in rat periodontal tissues were investigated both ultrastructurally and ultracytochemically. At day 5 after implantation, MNCs first appeared along the HAP surface. They had no features of typical osteoclasts such as ruffled border and clear zone. By d 14, these cells acquired features similar to osteoclasts, including ruffled border and clear zone. With the appearance of ruffled borders in MNCs, new bone deposited around the implanted HAP. MNCs appeared to excavate both newly‐formed bone and implanted HAP simultaneously. Ingested HAP particles were observed not only in MNCs but also in macrophages. MNCs contained both tartrate‐resistant acid phosphatase (ACPase) and carbonic anhydrase (CAase). ACPase activity was detected along all the biosynthesizing pathways in MNCs. Extracellular ACPase activity around the ruffled border region was also demonstrable. CAase activity could be detected only in the cytosol, vesicles and mitochondorial cristae of the MNCs. These cytochemical characteristics were almost the same regardless of the time elapsed after implantation.
Autoimmunity to collagen in adult periodontal disease: Immunoglobulin classes in sera and tissue
Authors: Anusaksathien O. , Singh G. , Matthews N. , Dolby A. E.
Published: July 2006

The immunoglobulin class distribution of antibody to human collagen type I has been examined in sera and gingival extracts from patients with adult chronic periodontitis. Tissue extracts were made either by simple washing or ultrasonication. With either method, IgG and IgA antibodies to collagen were present in higher concentration in tissue extracts than in autologous serum when adjustment was made for dilution differences. No significant differences were found for IgM antibodies. Antibodies to human collagen type I are usually “natural antibodies” of the IgM class and, therefore, our findings suggest a class switch to IgG in inflamed gingivae, presumably due to prolonged antigenic stimulation.