bluuebunny/crossref_metadata_2025 huggingface dataset:
Accessible sialic acid content of oral epithelial cells from healthy and gingivitis subjects
Authors: Davis G. , Gibbons R. J.
Published: July 2006

The purpose of the present study was to determine if there were differences in the quantity of accessible sialic acid on superficial epithelial cells collected from different areas of the mouth, and from healthy subjects with good oral hygiene, as compared to subjects with gingivitis. Superficial epithelial cells were collected by gently scraping the tongue dorsum, hard palate, free gingiva and buccal epithelium. The cells were washed and treated with clostridial neuraminidase to release accessible sialic acid; this was quantitated using a fluorometric assay. Buccal cells released an average of 62.6 ng sialic acid per 10000 cells, which was nearly 3‐fold more than cells from the hard palate (24.1 ng), free gingiva (21.9 ng), or tongue (15.4 ng). Buccal and free gingival cells collected from 5 healthy subjects had significantly higher levels of accessible sialic acid on their surface than cells collected from 5 subjects with gingivitis. These differences were significant at the p < 0.001 and p < 0.01 levels, respectively. The data obtained suggest that the oral hygiene status of an individual can influence the quantity of accessible sialic acid residues on oral epithelium; this would be expected to influence the attachment and colonization of bacteria which bind to sialic acid‐containing receptors.
Identification of polymorphonuclear leukocyte collagenase and gelatinase activities in mouthrinse samples: Correlation with periodontal disease activity in adult and juvenile periodontitis
Authors: Gangbar Stephen , Overall Christopher M. , McCulloch Christopher A. G. , Sodek Jaro
Published: July 2006

In previous studies, elevations in the levels of active and latent collagenase in gingival crevicular fluid (GCF) have been correlated positively with periodontal disease activity. To provide a simple diagnostic approach for testing collagenolytic activity, the feasibility of using a 3.0 ml water mouthrinse to collect GCF simultaneously from all sites in the mouth was assessed. Patients with adult periodontitis (AP, n = 23) and local juvenile periodontitis (LJP, n = 7) were sampled before periodontal therapy and some (12 AP, 4 LJP) were also assessed longitudinally after scaling and root planing, administration of antibiotics, and following periodontal surgery. Healthy patients (n = 19) were used as controls. The levels of active collagenase, procollagenase, and collagenase inhibitor activity were determined by functional assays and quantitated after SDS‐PAGE and fluorography. Gelatinase and progelatinase were assayed by enzymography on gelatin‐substrate gels. Active collagenase levels were found to be significantly higher (14‐ to 20‐fold) in AP and LJP patients compared to controls, whereas matrix metalloproteinase activity was not detected in mouthrinses from edentulous patients. Collagenase inhibitor levels were generally low in all groups of subjects tested. Following clinical treatment the levels of active collagenase and gelatinase were reduced; the reduction was significant for active collagenase after tetracycline treatment and scaling in LJP patients. Of the clinical indices recorded (gingival index, plaque index, and pocket depth) there were no significant correlations with enzyme activity but similar trends were observed between the changes in active collagenase and gingival index. In patients with untreated periodontal disease, collagenase occurred predominantly in the active form. N‐ethylmaleimide (NEM) and p‐aminophenylmercuric acetate (AMPA) were equally effective as activators of the latent collagenase, indicating that the collagenase was derived from PMNs, which were also the source of the gelatinase. The results of these studies indicate that measurement of active collagenase and gelatinase in mouthrinse samples is potentially useful in the diagnosis and assessment of periodontal disease activity.
Calibration errors in digital subtraction radiography
Authors: Webber Richard L. , Ruttimann Urs E. , Heaven Timothy J.
Published: July 2006

Two methods for the measurements of osseous change detected by digital subtraction radiography have been evaluated. Estimates of errors introduced by soft and hard tissues that overlay the region of interest (ROI) or by soft tissue that replaced the bone are made. All estimates are made assuming that the radiation source is a 40 keV monoenergetic beam and the reference Standard is equivalent to compact bone. These assumptions facilitate a theoretical analysis of calibration errors on a relative scale. The radiographic image method uses a calibration wedge on each of the two films. The mean gray value of the ROI on each film is converted into an equivalent thickness of bone by matching the ROI mean gray value to a gray value along the wedge. These thickness values are then subtracted to obtain a measurement of the amount of change. The subtraction image method makes use of a wedge on only one of the two films. The image of the subtraction of the two radiographs is used for detection of the area of change and the mean gray value of the ROI is matched to a gray value along the wedge. The thickness of the wedge at this point is the measured change. The errors introduced by inclusion of the cheek over the ROI and the replacement of bone by soft tissue are estimated for the radiographic image method. The influence of unequal beam attenuation between the reference ramp and the ROI is estimated for the subtraction image method. Other factors influencing the accuracy of estimates of osseous change which are nonlinear in their effects are also considered. These include the effects of scattered radiation, film response characteristics and x‐ray beam hardening.
Experimentally‐induced neurogenic inflammation in the rat oral mucosa
Authors: Fazekas Árpád , Vindisch Káimán , Pósch Elek , Györfi Adrienne
Published: July 2006

Blood flow and vascular permeability in the gingiva and alveolar mucosa of the lower jaw were studied after the antidromic (electric) or orthodromic (topical administration of capsaicin onto the oral mucosa) Stimulation of the inferior alveolar nerve (IAN) in rats with or without capsaicin pretreatment. Blood flow was determined using 86Rb isotope dilution technique, while vascular permeability was assessed by the Evans blue extravasation. Both antidromic or orthodromic stimulation of the IAN increased blood flow and Evans blue extravasation. Capsaicin pretreatment abolished the increase in gingivo‐mucosal blood flow and vascular permeability induced by nerve stimulation. The results of the present study appear to confirm the possibility of the development of neurogenic inflammation in the oral cavity. The mechanism observed may play a role in the development of certain inflammatory reactions in the oral mucosa frequently encountered in human clinical practice.
Changes in cytokeratin expression in gingiva during inflammation
Authors: Ouhayoun J. P. , Goffaux J. C. , Sawaf M. H. , Shabana A. H. M. , Collin C. , Forest N.
Published: July 2006

Cytokeratins represent specific markers of certain pathways of epithelial differentiation. The purpose of this study was to describe the alterations of cytoker atin pattern and topographical distribution of individual cytokeratins in in flamed gingiva. Five healthy and 15 inflammatory samples of human gingiva were studied. From each biopsy, cryostat sections allowed histological staining, immunofluorescence microscopy using a battery of monoclonal antibodies to cytokeratins, and gel electrophoresis. The results show marked differences in cytokeratin expression by healthy epithelia as compared with inflamed gingiva: in susprabasal cell layers there were reductions or disappearance of cytokeratins 1, 2 and 10, 11 ‐ specific for terminal differentiation ‐ and increased expression of cytokeratins 4 and 13, as well as ‐ in basal and parabasal cell layers ‐expression of cytokeratin 19. These alterations might represent an adaptation of involved epithelia to the alterations brought about by the inflammatory process.
Effect of infection with Eikenella corrodens on the progression of ligature‐induced periodontitis in rats
Authors: Samejima Yoshiaki , Ebisu Shigeyuki , Okada Hiroshi
Published: July 2006

The periodontopathic ability of Eikenella corrodens 1073‐R(EcR) on ligature‐induced periodontal defects in immunosuppressed and non‐immunosuppressed rats was studied bacteriologically and histologically. Silk ligatures were placed around the maxillary second molars of rats, and the rats were divided into eight groups. Four groups received cyclophosphamide (CY), an immunosuppressive agent, the day after ligature placement. On days 3 and 4, the oral cavities of the rats in all four groups were inoculated with 8 × 108 cells of live EcR. Rats were sacrificed on d 1, 3, 5, 8, 11 and 18. Alveolar bone resorption of ligated rats was enhanced by the implantation of EcR, although the number of total cultivable bacterial cells from ligated sites was not changed by the implantation of EcR. CY suppressed the number of white blood cells, inflammatory cellular infiltrates in gingival tissue, and repair of periodontal tissue, and enhanced bone destruction. The implantation of EcR in the ligature‐ and CY‐treated rats also enhanced osteoclastic bone resorption. Without ligatures, high doses of CY or EcR inoculum did not result in periodontal destruction. These results indicate that it is possible to establish EcR in conventional rat flora with a ligature and that EcR causes osteoclastic bone resorption in this model.
Alterations in cell morphology and cytoskeletal proteins in gingival fibroblasts exposed to a Bacteroides gingivalis extract
Authors: Phillips John R. , Nadim Hany S. , Layman Don L.
Published: July 2006

A soluble sonic extract (SSE) from Bacteroides gingivalis caused a dose‐dependent inhibition of gingival fibroblast growth, reduced cell attachment and altered cell morphology. Most of its cytotoxic activity was destroyed by heating, indicating that the factor(s) was a protein rather than endotoxin. Cells, grown in the presence of, or on, root surfaces pretreated with 100–200 μg SSE/ml, partially retracted from the substratum and exhibited extensive surface blebbing and finger‐like protrusions. Immunofluorescent staining showed that the morphological effects of Bacteroides gingivalis SSE are directed specifically at actin stress fibers and not microtubules of the cytoskeleton. Exposure to the SSE resulted in a dramatic relocalization of the bulk of F‐actin from a fibrous form to a non‐aggregated diffuse form. Disorganization of actin stress fibres occurred at concentrations of SSE that inhibited cell growth, but preceded any observable changes in cell attachment or morphology. The microtubular network remained intact, although it stained less intensely than that of controls. By contrast, Bacteroides intermedius SSE did not significantly influence growth, alter cellular morphology or affect the two cytoskeletal proteins.
Deficiency of salivary PAF in edentulous individuals
Authors: McManus L. M. , Marze B. T. , Schiess A. V.
Published: July 2006

PAF, a potent phospholipid mediator of inflammation, is present in normal human, mixed saliva. However, the anatomic origin of PAF is not known. In this study, PAF levels in mixed saliva of edentulous subjects were estimated in comparison to that of dentate individuals. PAF activity was assessed in bioassay and expressed relative to the activity of known amounts of authentic PAF, 1‐O‐hexadecyl‐2‐acetyl‐sn‐glycero‐3‐phosphocholine (AGEPC). PAF was not detected in the saliva of 60% of the edentulous subjects; moreover, when present, the PAF levels were significantly less (635 ± 82 AGEPC fmole equivalents/ml saliva, mean ± SEM, n = 6) than in dentate subjects (5568 ± 1135 AGEPC fmole equivalents/ml saliva, n = 27). Of relevance, the numbers of polymorphonuclear leukocytes in the mixed saliva samples of edentulous subjects were markedly reduced when compared to those of normal subjects. These findings suggest that salivary PAF most likely originales from the crevicular space, and derives from inflammatory cells within the gingival and/or periodontal tissues.
Granulocyte medullasin levels in gingival crevicular fluid from chronic adult periodontitis patients and experimental gingivitis subjects
Authors: Kunimatsu Kazushi , Ichimaru Eiji , Kato Lhachi , Kato Yuzo , Sonoda Yasutaka , Aoki Yosuke , Yamamoto Kenji
Published: July 2006

The concentration of medullasin, an elastase‐like serine proteinase, in gingival crevicular fluid (GCF) from chronic adult periodontitis patients and experimental gingivitis subjects was determined by the highly sensitive immunoassay method. In periodontitis patients, the medullasin content increased with increase of the GCF volume and then attained a maximum value at a relatively mildly inflamed stage. The value was maintained through more serious stages of disease activity. However, the medullasin content was independent of the probing depth. The medullasin content of the patients was markedly decreased after periodontal treatment, indicating that the enzyme participates in the development of the chronic periodontitis. Large amounts of medullasin were also detected in GCF from experimental gingivitis subjects, although it was not detected by the activity measurements. There was a rapid increase in the medullasin content during the 4‐day period after abstention from oral hygiene measures, which corresponded to those of severely inflamed periodontitis patients. The peak value decreased up to the 7th‐d followed by a gradual increase during the 21‐d experimental period. The increased medullasin level rapidly decreased following resumption of oral hygiene measures. The results suggest that medullasin plays important roles both in the defence mechanism against the gingival inflammation and in the development of the acute inflammation.
Electron‐immunocytochemistry of laminin and type‐IV collagen in the junctional epithelium of rat molar gingiva
Authors: Sawada Takashi , Yamamoto Takashi , Yanagisawa Takaaki , Takuma Shosaburo , Hasegawa Hideaki , Watanabe Keiichi
Published: July 2006

The present study was carried out to examine the ultrastructural localization of laminin and type‐IV collagen in the junctional epithelium of rat molar gingiva by means of the indirect immunoperoxidase method. Intense laminin reaction occurred in both the internal and the external basal laminae. Laminin reaction products were observed within the cisternae of the rough endoplasmic reticulum of junctional epithelium cells and in concavities formed at the distal plasma membranes adjacent to the basal lamina. Small spherical bodies occurring in the concavities also reacted positively to laminin. Type‐IV collagen reaction was intense in the external basal lamina. The internal basal lamina, however, showed no reaction for type‐IV collagen. These results indicate that the internal basal lamina contains laminin but no type‐IV collagen and that junctional epithelium cells seem very likely to be involved in the production of laminin.
Binding specificity of Fusobacterium nucleatum to human erythrocytes, polymorphonuclear leukocytes, fibroblasts, and HeLa cells
Authors: Ozaki Masaharu , Miyake Yoichiro , Shirakawa Masaharu , Takemoto Toshinobu , Okamoto Hiroshi , Suginaka Hidekazu
Published: July 2006

Eighteen strains ofFusobacterium nucleatumwere studied with respect to their adherence to human erythrocytes, polymorphonuclear leukocytes, fibroblasts, and HeLa cells. Four types of adherence were found: 1) sugar‐sensitive adherence 2) amino acid‐sensitive adherence 3) unknown adherence 4) weak adherence. There was no obvious correlation between the patterns of hemagglutination and adherence to other cells. The results indicate not only a complex network of bacterial receptors on human cells, but also a variety of types of bacterial adherence as expressed by the selectivity of the bacterial binding to specific cell surfaces.
Measurement of interleukin‐1α and ‐1β in gingival crevicular fluid: Implications for the pathogenesis of periodontal disease
Authors: Masada Marvin P. , Persson Rutger , Kenney John S. , Lee Simon W. , Page Roy C. , Allison Anthony C.
Published: July 2006

Samples of gingival crevicular fluid (GCF) were harvested from sites manifesting features characteristic of active disease including inflammation, periodontal attachment loss, and radiographic signs of alveolar bone destruction in untreated patients with advanced periodontitis. The presence and concentrations of interleukin‐lα (IL‐lα) and interleukin‐1β (IL‐1β) were measured using ELISAs specific for these cytokine molecules. IL‐lα and/or IL‐1β were identified in the GCF of 15 of 15 patients having untreated periodontitis. Ninety percent (71 of 79) of the sites tested contained measurable amounts of IL‐l. with IL‐lβ as the more frequently occurring form. IL‐lα levels ranged from 0.23 nM to 13.9 nM in the GCFs. IL‐1β levels were between 0.04 nM and 5.28 nM. Marked reductions of total IL‐1 levels were observed following effective treatment. Both forms of IL‐1 messenger RNA (mRNA) were detected in 17 of 17 gingival tissue samples from 6 patients. These results demonstrate that IL‐1 is produced and released locally in periodontal disease at concentrations sufficient to mediate tissue inflammation and bone resorption. IL‐1 may serve as a marker of periodontal tissue destruction.
Fibroblastic cells derived from bovine periodontal ligaments have the phenotypes of osteoblasts
Authors: Nojima N. , Kobayashi M. , Shionome M. , Takahashi N. , Suda T. , Hasegawa K.
Published: July 2006

We examined the possibility that periodontal ligament (PDL) cells can differentiate into osteoblasts and/or cementoblasts in freshly isolated PDL tissues and in cultured cells derived from PDL. PDL tissues were obtained from the incisor teeth of bovine lower jaws; gingival connective tissues of the same animals were used as controls. Freshly isolated PDL tissues and cultured PDL cells showed an intense alkaline phosphatase (ALPase) activity both histochemically and biochemically. The production of 3′, 5′‐cyclic adenosine monophosphate (cAMP) was greatly increased in response to human parathyroid hormone [PTH(1‐34)], in both freshly isolated PDL tissues and cultured PDL cells. In contrast, neither ALPase activity nor PTH‐dependent cAMP production was detected in gingival connective tissues and cultured gingival fibroblasts. Furthermore, cultured PDL cells synthesized a protein immunologically cross‐reactive with bovine bone gla protein (BGP), a highly reliable marker of osteoblastic cells. When 10−8 M lα, 25‐dihydroxyvitamin D3 [lα,25(OH)2D3] was added to the PDL cell cultures, the synthesis of the BGP‐like protein was increased 2‐ to 3‐fold. The maximal level of the synthesis was obtained 72 h after the addition of lα,25(OH)2D3 Gingival fibroblasts cultured with or without lα,25(OH)2D3 did not produce any appreciable amounts of the BGP‐like protein. These results indicate that the PDL cells have phenotypes typical of osteoblasts, indicating that they may differentiate into osteoblasts and/or cementoblasts.
Some predictors of radiographic alveolar bone height reduction over 6 years
Authors: Albandar Jasim M.
Published: July 2006

The present study was undertaken to 1) develop a model to predict the proportion of sites with alveolar bone height reduction over 6 years by means of a few factors, 2) build a second model to predict the initial values of the dependent variable, and 3) describe the relationship between initial bone loss and the bone loss over 6 yr with age. 142 subjects (18–67 yr) were examined radiographically at baseline and 6 yr later using a standardized method. For each subject, the proportion of sites depicting significant alveolar bone height reduction during the study was assessed. Explanatory variables were: presence of initial bone loss, local plaque retaining factors, age, sex, number of missing teeth at baseline and rheumatoid arthritis. Employing multiple regression analysis, the combined effect of initial bone loss, plaque retaining factors, age and rheumatoid arthritis provided the best model suited to predict the proportion of sites undergoing bone loss over time. However, age, plaque retaining factors and number of missing teeth were the best predictors of initial bone loss. A logistic regression model was then used to study the significance of these predictors at the site level. This model indicated that alveolar bone loss over time at a given site is related mainly to presence of local factors and initial bone loss at that site as compared to the effect of other sites with local factors and initial bone loss in the subject. Age demonstrated a linear relationship with initial bone loss and a curvilinear relationship to periodontal disease progression. It was concluded that the reported findings may be helpful in defining criteria for the detection of subjects at high risk of undergoing periodontal breakdown. In addition, it seems that results from cross‐sectional studies on the loss of periodontal support may not directly infer periodontal disease progression.
Local ofloxacin delivery using a controlled‐release insert (PT‐01) in the human periodontal pocket
Authors: Higashi Kiyotsugu , Morisaki Katsuhiko , Hayashi Shin'ichi , Kitamura Masahiro , Fujimoto Naoki , Kimura Shigenobu , Ebisu Shigeyuki , Okada Hiroshi
Published: July 2006

PT‐01, a controlled‐release insert, was developed for topical chemotherapy in periodontal disease. It is a soluble insert that consists of fast‐release and sustained‐release parts containing ofloxacin (OFLX) as an antibacterial agent. In this study, the release profile of OFLX from PT‐01 was investigated in vitro. Twelve adult volunteers were administered OFLX as PT‐01 or as an aqueous solution into their periodontal pockets, OFLX concentrations in gingival crevicular fluid (GCF) were evaluated from the viewpoint of pharmacokinetics. The in vitro release profile of OFLX from PT‐01 showed a biphasic pattern. The release rate of OFLX was relatively rapid in the early phase and slow thereafter. When OFLX aqueous solution was administered into periodontal pockets, the OFLX level in GCF rapidly decreased to be about 1/100 after 30 minutes. When PT‐01 was inserted into the pockets, the OFLX level in GCF immediately reached a peak (about 12 mg/ml), and gradually decreased until the 3rd day, and maintained a constant level above 2 μg/ml, the effective minimum antibacterial concentration for periodontopathic microorganisms, from the 3rd to 7th day after insertion. No side‐effects were observed in the volunteers who received the PT‐01 insert. The above results suggest that PT‐01 is a suitable pharmaceutical preparation for periodontal chemotherapy.
Androgen metabolism in gingival hyperplasia induced by nifedipine and cyclosporin
Authors: Sooriyamoorthy M. , Gower D. B. , Eley B. M.
Published: July 2006

Three cases of gingival overgrowth induced by cyclosporin and/or nifedipine have been reported. Patient A was under medication with cyclosporin plus nifedipine, Patient B with nifedipine only and Patient C with cyclosporin only. The significance of androgen metabolism in gingival tissue, with respect to hyperplastic changes has been studied by several workers. Hence, we have investigated whether gingival tissue from the above patients showed significant metabolism of the androgen, testosterone, to its biologically‐active form, 5α‐dihydrotesto‐sterone (5α‐DHT). Radical gingivectomy was carried out in all 3 cases to remove the hyperplastic tissue. The excised tissue was incubated with labelled testosterone in order to study the extent of androgen metabolism. Healthy gingivae from males and females produced 5α‐DHT (22.4 ± 7.7, s.e.m., n – 8). Very significantly higher values (p < 0.001) were recorded for Patients A, B and C (1139, 542 and 994 fmol/mg, respectively). These represented increases of 51‐, 24‐ and 44.4‐fold, respectively over control values. Corresponding production of 4‐andro‐stenedione from testosterone was 28±8.3, s.e.m., n = 8, fmol/mg. In Patients A, B and C, 4‐androstenedione production was elevated: 85, 901 and 113 fmol/mg, respectively, representing increases of 3‐, 32‐ and 4‐fold. Even the lower values of 85 and 113 fmol/mg were very highly significant (p < 0.001) compared with control values. Although healthy female gingival tissue does not metabolize testosterone significantly, in the presence of inflammation the extent of 5α‐DHT formation is comparable to that of male samples. For comparative purposes, the results of a previous study relating to phenytoin and androgen metabolism are included, since phenytoin is the third of the main drugs which cause the gingival overgrowth phenomenon. The relevant part of the study concerns the effects of phenytoin on a 180 g supernatant of fibroblasts derived from inflamed tissue. At a concentration of 10 μg/ml, phenytoin caused an approximately 160‐fold increase in 5α‐DHT formation from testosterone in the inflamed tissue fibroblast preparation compared with the non‐inflamed preparation.
Immunohistochemical distribution of keratin proteins in human gingival heterotransplants in nude mice
Authors: Juhl M. , Holmstrup P. , Reibel J. , Andreasen J. O.
Published: July 2006

Clinically healthy human gingivae from deciduous molar regions were transplanted to subcutaneous sites of nude mice (nu/nu NC). Transplants were harvested after posttransplantation periods of 5, 6, 7, 8.5, 10.5 and 12 weeks and examined histologically after staining with hematoxylin‐eosin (H.E.), bisbenzimide, and a panel of mouse monoclonal anti‐keratin antibodies in an indirect fluorescence technique. Central parts of transplants contained human connective tissue covered by human stratified squamous epithelium which were unkeratinized in 5‐ to 7‐wk‐old transplants and most frequently (75%) parakeratinized in 8.5‐wk to 12‐wk transplants. Comparison of keratin expression before and after transplantation revealed a progressive keratin reconstitution, i.e., keratin markers of basal/suprabasal cells preceded those of suprabasal/spinous cell layers and immunohistochemical markers of keratinization preceded routine histologically observed parakeratinization. Original keratin staining and essential features of histodifferentiation were reconstituted and maintained after 8.5 wk but graft recovery rate decreased drastically 12 wk after transplantation. This study shows that the human gingiva/nude mouse model is useful in experimental studies of the gingival keratin profile in the period 8.5 to 10.5 wk after transplantation.
Gingival crevicular fluid elastase‐inhibitor complex: correlation with clinical indices and subgingival flora
Authors: Zafiropoulos G.‐G. K. , Flores‐de‐Jacoby L. , Todt G. , Kolb G. , Havemann K. , Tatakis D. N.
Published: July 2006

This investigation analyzed, in a cross‐sectional study, the possible relationship between gingival crevicular fluid (GCF) elastase‐like protease (ELP) levels and the periodontal clinical parameters or the presence of specific bacteria in subgingival plaque. A total of 388 periodontal sites from 8 adult periodontitis patients were examined for plaque index (P1I), gingival index (GI), pocket depth (PD) and alveolar bone loss (ABL). GCF ELP levels were determined as ELP alpha‐1 protease inhibitor (ELP‐α1‐PI) complex levels with a commercially available ELISA. Subgingival plaque samples were tested for the presence of Bacteroides gingivalis, B. intermedius and Actinobacillus actinomycetemcomitans by indirect immunofluorescence (IF) microscopy. GCF ELP‐α1‐PI levels were then correlated with clinical periodontal indices and proportions of IF‐positive bacteria per site. Statistically significant positive correlations were found between GCF ELP‐α1‐PI concentrations and subgingival Bacteroides proportions. When the sites examined were analyzed depending on the level of each clinical parameter, the levels of these correlations changed. A. actinomycetemcomitan correlated highly (r = 0.716) with ABL for sites with low GI score. The correlations between GCF ELP‐α1‐PI and B. gingivalis (r = 0.642) or B. intermedius (r = 0.774) were the highest for ABL ≤ 20% and PD ≤ 3 mm, respectively. The strong association between GCF ELP‐α1‐PI concentrations and subgingival bacteria previously associated with advancing periodontitis indicates that measurement of GCF ELP‐α1‐PI concentrations may be useful in the evaluation of periodontal sites, especially those with very little or no tissue destruction.
Topical chemotherapy in human periodontitis using a new controlled‐release insert containing ofloxacin. I. Microbiological observation
Authors: Kimura S. , Toda H. , Shimabukuro Y. , Kitamura M. , Fujimoto N. , Miki Y. , Okada H.
Published: July 2006

The recognition that destructive periodontal diseases may be caused by specific microorganisms in periodontal pockets has led to an increased interest in and usage of antimicrobial agents in periodontal therapy. Recently, a new controlledrelease insert containing ofloxacin, a synthetic antibiotic, has been developed. In this study, the controlled‐release insert (PT‐01) was microbiologically evaluated in combination with or without subgingival mechanical debridement. PT‐01 was applied in the periodontal pockets of 27 patients with chronic periodontitis. Three sites with a deep probing pocket depth (≥5 mm) were randomly selected in different quadrants of each patient, and were assigned into three groups, i.e., PT01 applied (T), placebo applied (P) and control sites (C). Periodontal treatments consisted of supragingival scaling with oral hygiene instruction for the first 2 weeks followed by root planing and subgingival scaling. PT‐01 was applied weekly on day 0 to 35, and the subgingival plaque samples from each site were collected on d 0, 14, 21 and 42. The dynamics of the subgingival microflora was investigated by dark field microscopy and by anaerobic and aerobic cultivation. In the supragingival scaling period, significant reduction in percentages of spirochetes and motile rods and significant increase of the percentage of coccoid cells were observed only at T sites. In addition, the total viable counts of bacteria, black‐pigmented Bacteroides and Fusobacterium species were significantly reduced at T sites. After mechanical subgingival debridement, significant shifts in the proportion and reduction of the viable counts in the subgingival microflora were found at all sites. Although PT‐01 applied sites showed some further shift in the proportion and reduction in subgingival microorganisms, statistically no significant differences in the microbiological results between the three groups of experimental sites were found. These results suggested that weekly application of PT‐01 in the periodontal pocket could have significant effects on both qualitative and quantitative changes in the subgingival microflora. However, the mechanical subgingival debridement, consisting of root planing and subgingival scaling, was very effective in eliminating the subgingival microflora by itself. Then, in the combination with mechanical subgingival debridement, statistically no additional effects could be found. Consequently, it was suggested that the application of PT‐01 might have an ameliorating effect as an adjunct in conventional periodontal therapy.
Cells from Hertwig's epithelial root sheath do not transcribe amelogenin
Authors: Luo W. , Slavkin H. C. , Snead M. L.
Published: July 2006

Recent experimental evidence has led to the Interpretation that “enamel‐like” material is deposited along the forming mouse molar root surface by cells of Hertwig's epithelial root sheath (HERS cells) and that this material is integral to the developmental program for cementogenesis. The experimental strategy described in this study was to examine selected developmental stages of root formation for mouse first and second mandibular molars in order to localize the cellular sites of amelogenin gene transcripts using high resolution in situ hybridization. Amelogenin is the major structural protein of coronal enamel and is highly conserved among mammalian species at the DNA and amino acid sequence level. Within the limits of sensitivity for in situ hybridization and utilizing either cRNAs or oligodeoxynucleotide probes, we were unable to localize amelogenin transcripts within HERS cells from selected developmental stages associated with mouse molar root formation. In contrast, previous studies using antipeptide antibodies have provided immuno‐histochemical localization of amelogenin domains in HERS cell‐derived products. For these HERS cell‐derived proteins to contain both amelogenin epitopes and yet fail to yield nucleic acid hybridization Signals suggests that either gene rearrangement and/or alternative processing of messenger RNAs from the structural gene locus operate to produce immunologically related motifs sharing insufficient complementarity at the nucleotide level to permit efficient detection by hybridization. It is postulated that HERS cells synthesize proteins which contain amelogenin domains and that these proteins participate during cementogenesis. However, these enamel‐related proteins are neither identical to, nor collinear with coronal canonical amelogenin transcripts.
Suppression of human neutrophil functions by tetracyclines
Authors: Gabler Walter L. , Creamer Howard R.
Published: July 2006

Tetracycline inhibition of neutrophil‐associated collagenolysis has been the focus of a number of investigations. Evidence has suggested that this inhibition results from the ability of this family of antimicrobial drugs to bind divalent cations such as Ca2+ and Zn2+, two cations that are required for full expression of activity of metalloproteinases such as collagenase and gelatinase. Data presented in this study demonstrate that tetracyclines can also inhibit neutrophil‐mediated RBC lysis, superoxide anion synthesis, degranulation and migration. To some extent, tetracycline inhibition of neutrophil functions is mimicked by the Ca2+ binding agents, EDTA and TMB‐8. However, Ca2+ enrichment restored full function to EDTA‐ and TMB‐8‐treated cells but not to tetracycline‐treated neutrophils. This suggests that Ca2+ binding plays a role but is not the critical effect leading to tetracycline suppression of neutrophil functions. It has been suggested that tetracyclines can suppress leukocyte‐associated tissue damage. Host tissues are protected from neutrophil‐mediated damage by two mechanisms: 1. Neutrophil granule‐associated enzymes are secreted in an inactive state; and, 2. tissues are protected from these enzymes by a potent inhibitor shield. Neutrophils can bypass these protective elements by activating enzymes and by destroying the shield through the synthesis of oxygen radicals. Therefore, tetracyclines may suppress neutrophil‐mediated tissue damage by inhibiting their migration and degranulation and, potentially more importantly, by suppressing synthesis of oxygen radicals. Before the anti‐inflammatory properties of the tetracyclines can be most safely and effectively used in treating conditions where inflammatory tissue damage is a significant part of the disease process, a more complete understanding of the mechanisms involved in their inhibition of PMN function will be required.
A longitudinal study of aspartate aminotransferase in human gingival crevicular fluid
Authors: Chambers Donald A. , Imrey Peter B. , Cohen Rhonna L. , Crawford John M. , Alves Mario E.A.F. , McSwiggin Theresa A.
Published: July 2006

Previous studies have shown that aspartate aminotransferase (AST), an established serum marker for cardiac and liver damage in humans, appears in elevated concentrations in samples of gingival crevicular fluid (GCF) from ligated vs. non‐ligated teeth in beagle dogs and in elevated quantities in cross‐sectional GCF sampling, adjusted for collection time, from human sites with clinical signs of past or present periodontal disease as compared to healthy sites. This paper describes a longitudinal study in which AST was monitored quarterly over a 2‐ year period at 2 sites/tooth in 31 patients with mild to moderate adult periodontitis. In this study sample, 40 (2.6%) of 1536 sites exhibited confirmed loss of at least 2 mm of attachment during the 2‐yr observation period. In comparison with healthy sites within the same patients, AST standardized to a 30‐second collection interval (AST30) was elevated at these sites with new confirmed attachment loss, and at sites with past attachment loss or gingivitis in the absence of periodontitis. When both within‐ and between‐patient variation were taken into account, observed odds‐ratios associating enzyme with disease were higher for sites with new attachment loss (9–16 depending on test cut‐point) than for sites with pre‐study attachment loss (3–12), or gingivitis in the absence of periodontitis (5–8). AST in GCF is strongly related to human periodontal disease. The data are consistent with the hypothesis that the relationship is strongest during episodes of cumulative tissue breakdown, but the small numbers of sites with confirmed attachment loss during the study period, or with gingivitis in the absence of periodontitis, means that further clinical studies are necessary to clarify this issue.
Effect of region‐of‐interest in computerized densitometric analysis of radiographs
Authors: Steffensen B. , Bräagger U. , Yuan C. , Pasquali L. A. , Brunsvold M. , Kornman K. S.
Published: July 2006

The region‐of‐interest (ROI) in computer‐assisted densitometric image analysis (CADIA) is defined by its size and location. This study evaluated the effects of these variables on two quantitative parameters, the change in density and the area with change in density. Pairs of radiographs for these analyses were obtained from sites with “no change” or “known loss” in Cynomolgus monkeys during a study of ligature‐induced periodontitis. The size and location of the ROI had clear effects on the two CADIA parameters. To reduce these effects, a corrective procedure hypothesizing a linear relationship between the ROI size and the area with change in density was tested. While this procedure was sufficient to correct for ROI size‐dependent differences among “no change” images, it was not effective in images with “known loss”. In such images, additional adjustments by increasing threshold levels for the registered change in density were found to reduce but not to eliminate differences between ROIs of different size and location. When densitometric radiographic analysis is used for quantitative comparison of different sites, it is primarily recommended to select ROIs of similar size and location. Application of corrective procedures should follow only after careful evaluation of their effects on sensitivity and specificity.
Immune responses to implanted human collagen graft in rats
Authors: Quteish D. , Dolby A. E.
Published: July 2006

Immunity to collagen implants may be mediated by cellular and humoral immune responses. To examine the possibility of such immunological reactivity and crossreactivity to collagen, 39 Sprague‐Dawley rats (female, 10 weeks old, approximately 250 g wt) were implanted subcutaneously at thigh sites with crosslinked, freeze‐dried human placental type I collagen grafts (4×4×2 mm) which had been irradiated (520 Gray) or left untreated. Blood was obtained by intracardiac sampling prior to implantation or from normal rats, and at various times afterwards when the animals were sacrificed. The sera from these animals were examined for circulating antibodies to human, bovine and rat tail (type I) collagens by enzyme‐linked immunosorbent assay (ELISA). Also, the lymphoblastogenic responses of spleen lymphocytes from the irradiated collagen‐implanted animals were assessed in culture by measuring thymidine uptake with autologous and normal rat sera in the presence of human and bovine type I collagens. Implantation of the irradiated and non‐irradiated collagen grafts in rats led to a significant increase in the level of circulating antibodies to human collagen. Also antibody to bovine and rat tail collagens was detectable in the animals implanted with irradiated collagen grafts but at a lower level than the human collagen. There was a raised lymphoblastogenic response to both human and bovine collagens. The antibody level and lymphoblastogenesis to the tested collagens gradually decreased towards the end of the post‐implantation period.
Distribution of collagens type V and VI in the normal human alveolar mucosa: An immunoelectronmicroscopic study using ultrathin frozen sections
Authors: Rabanus J. P. , Gelderblom H. R. , Schuppan D. , Becker J.
Published: July 2006

The ultrastructural localization of collagens type V and VI in normal human gingival mucosa was investigated by immunoelectron microscopy. Twenty biopsies were fixed in dimethylsuberimidate and shock‐frozen in slush nitrogen. Collagen type V was mainly located to meshworks of uniform nonstriated microfibrils of 12 to 20 nm width, which preferentially appeared in larger spaces between cross‐striated major collagen fibrils. Occasionally single microfibrils of collagen type V fanned out from the ends of major collagen fibrils, which may indicate a role as a core fibril. Collagen type V was not found in the subepithelial basement membrane and the immediately adjacent stroma. Collagen type VI was detected in a loose reticular network of unhanded microfilaments that were morphologically distinguishable by knoblike protrusions every 100–110 nm. These microfilaments were found in the vicinity, but not as an intrinsic component, of the subepithelial basement membrane. Single filaments of collagen type VI filaments appeared to form bridges between neighboring cross‐striated major collagen fibrils, suggesting an interconnecting role for this collagen type. The method presented appears to be excellently suited to study the normal and pathological supramolecular organization of the oral extracellular matrix.
Role of fibroblast subpopulations in periodontal physiology and pathology
Authors: McCulloch Christopher A. G. , Bordin Sandra
Published: July 2006

Fibroblasts are the principal cell type in the soft connective tissues of the periodontium; they perform important functions in development, physiology, and disease. A growing number of reports have indicated site‐specific phenotypic variation of fibroblasts. Heterogeneity of metabolic traits has been demonstrated in cells from healthy and diseased tissues. The tissue distribution and relative proportions of fibroblast subpopulations have a significant impact on the regulation of connective tissue function in health and disease.
Measurement of relative avidity of antibodies reactive with Porphyromonas (Bacteroides) gingivalis in the sera of subjects having adult periodontitis
Authors: Lopatin Dennis E. , LaBelle Douglas , Lee Seok‐Woo
Published: July 2006

Relative avidities of antibodies to Porphyromonas (Bacteroides) gingivalis in the sera of 15 patients having adult periodontitis and 15 healthy subjects were evaluated using an ammonium thiocyanate‐dissociated ELISA. Graded concentrations of ammonium thiocyanate were added to a single dilution of serum in order to dissociate low avidity antibody binding to P. gingivalis. The concentration of thiocyanate resulting in 50% reduction in binding (absorbance) was termed the ID50 for that serum. When IgG‐class antibodies were examined, the ID50 of anti‐P. gingivalis antibodies in the sera of patients was significantly elevated (0.96M vs 0.71M; p<0.01, Student's t‐test). In contrast, when IgM‐class antibodies were examined no significant differences in ID50 between patients and controls were found for P. gingivalis (0.54M vs 0.53M). While the ID50 values of patient antibodies were found to be elevated relative to those of healthy controls, comparison with antibodies from rabbits immunized with P. gingivalis and with ID50 values from other human studies suggests that adult humans, in general, produce very low‐avidity antibodies to P. gingivalis. It is suggested that the presence of low‐avidity antibodies contributes to the pathology associated with periodontal disease.
A fractal model for periodontal breakdown in periodontal disease
Authors: Landini Gabriel
Published: July 2006

This paper presents a computer model of periodontal breakdown based on 1/f noise. The model is multifactorial and simulates the disease advancing with age in bursts and remissions, as seen in previous epidemiologic studies. Changing the weight of some parameters changed the simulated periodontal breakdown dramatically, disclosing antagonistic and synergistic effects between the causal factors.
Serological studies of Porphyromonas (Bacteroides) gingivalis and correlation with enzyme activity
Authors: Nagata A. , Man‐yoshi T. , Sato M. , Nakamura R.
Published: July 2006

Porphyromonas gingivalis from the human oral cavity was serologically characterized using absorbed and unabsorbed rabbit antisera. The reference strains were ATCC 33277, W50, W83, 381 and hara 1. The 432 isolates were from periodontal pockets of 63 patients with adult periodontitis. Using sonicated antigens, four serotypes were identified by immunodiffusion tests and immunoelectrophoresis. Each patient harbored only one serotype of P. gingivalis, and serotypes I and IV predominated. The incidence of serotype I was four times higher than that of serotype II, and approximately seven times higher than that of serotype III. The collagenolytic and some proteolytic enzymes of representatives of each serotype were assessed. Although all strains produced these enzymes to some degree, some differences in their levels were observed. Serotype II strains were more collagenolytic than serotypes I or III, and serotype III exhibited lower activities of N‐CBz‐glycyl‐glycyl‐arginyl peptidase than other serotypes. Antibiotic sensitivity was also compared with antimicrobial disks, and serotype IV strains exhibited high sensitivity to the four antibiotics used.
Measurement of associations in periodontal diseases using statistical methods for dependent data
Authors: DeRouen Timothy A. , Mancl Lloyd , Hujoel Philippe
Published: July 2006

Clinical studies of periodontal diseases often involve obtaining observations for variables measured at multiple sites within each patient studied. These observations are thus inherently dependent, and the use of standard statistical methods to measure associations among the variables is inappropriate since they ordinarily assume independence among observations. Methods are suggested for extending standard statistical methods to the situation where data are dependent. For example, if the sensitivity and specificity of a diagnostic test is of interest, the usual binomial distribution, which assumes independence, can be replaced with the correlated binomial, and these characteristics can still be estimated in the presence of correlated data. In situations where the interrelationships of several variables to a response would ordinarily be investigated using multiple linear or logistic regression, the presence of correlated data such as that arising from clinical studies of periodontal disease requires that adjustments be made to account for the correlation. One of the most promising methods for taking such correlation into account is the use of generalized estimating equation (GEE) methodology, which is described in this paper and employed in two examples. The two examples involve measuring the association of levels of aspartate aminotransferase (AST) with tissue destruction, and the evaluation of the effects of metronidazole and surgery on attachment level in different groups of chronic periodontitis patients. Several statistical approaches and their conclusions are compared for each of the examples. GEE methodology allows the extension of standard regression models to situations involving dependent data while maintaining the ease of interpretation associated with regression results.