bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tetracycline treatment of periodontal disease in the beagle dog
Authors: Williams R. C. , Leone C. W. , Jeffcoat M. K. , Nitzan D. , Goldhaber P. 
Published: July 2006

The flora of periodontal pockets < 6 mm and the rate of alveolar bone loss of one diseased site in each of eighteen adult beagle dogs were compared during a 6 month pretreatment period and a subsequent 12 month tetracycline treatment period. The dogs were divided into the following three groups and treated as follows: untreated controls (5), 250 mg tetracycline daily (5), and 500 mg tetracycline daily (7). An attempt was made to correlate the flora in deep periodontal pockets and the subsequent rate of alveolar bone loss in untreated control beagles and beagles treated with tetracycline (250 mg per day and 500 mg per day). The bacterial flora and the rate of bone loss of one site in each dog was compared during a six‐month pretreatment period and a subsequent twelve‐month tetracycline treatment period. The cultivable flora was classified according to cellular morphology. Gram stain, and atmospheric tolerance.The periodontal pocket flora was predominantly a Gram negative anaerobic flora at all time periods throughout the study. The flora of the untreated control dogs spontaneously shifted to a more Gram negative flora at 18 months of the study. In the treated dogs, after six months of tetracycline treatment, there was a significant shift to a more Gram negative flora which returned to baseline proportions after twelve months of treatment. A decrease in the numbers of bacteria sensitive in vitro to tetracycline was found in the course of the treatment period. No significant relationship was found between the cultivable flora of a specific site and the rate of alveolar bone loss for that site.The data suggest that in advanced periodontal disease in the beagle dogs studied a Gram negative anaerobic flora was predominantly cultivated. Broad groupings of bacteria cultivated from each site did not correlate with the rate of alveolar bone loss of each site.
Effects of Actinomyces and Fusobacterium on humoral immune response in vitro
Authors: Yoshie Hiromasa , Mitsuma Takashi , Kozima Keniti , Hara Kohji 
Published: July 2006

The purpose of this study was to examine the effects of Actinomyces viscosus and Fusobacterium nucleatum sonicates on antibody formation in vitro and to elucidate their mechanisms on the cellular basis. Suspensions of A. viscosus and F. nucleatum were sonicated, and the supernatant was filtered and heated. After AKR mouse spleen cells were stimulated with sheep red blood cells, the antibody formation was assayed by counting the plaque‐forming cells (PFC). Macrophages, T‐ and B‐cells were harvested from the mouse peritoneal exudate and spleen. Mitogenicity of the sonicates was determined by counting the uptake of 3H‐thymidine.The PFC number, when A. viscosus or F. nucleatum sonicate was added, increased significantly by 2.4–6.6 times more than the control. Two sonicates were found to activate the macrophages, resulting in an increase of PFC. F. nucleatum sonicate was effective to PFC response via activation of helper T‐cells. Stimulation index of F. nucleatum sonicate on T‐cells was 4.1 and that of A. viscosus sonicate on B‐cells was 3.2. In conclusion, the enhanced antibody formation by A. viscosus sonicate depends on the activation of macrophages and B‐cell mitogenicity, and the F. nucleatum sonicate enhances the PFC response by activation of both macrophages and helper T‐cells and by T‐cell proliferation.
Murine model for analysis of the immune response to oral colonization
Authors: Fitzgerald John E. , Gebhardt Bryan M. , Birdsell Dale C. 
Published: July 2006

The overall aim of this work was to analyze the role of the immune response to a known periodontal pathogen, Actinomyces viscosus T14V, in orally superinfected Balb/c mice. The mice did not contain A. viscosus in the oral cavity prior to superinfection. Colonization by superinfecting A. viscosus was specific for the tooth surface.When mice were placed on a soft, high‐carbohydrate diet and superinfected with varying doses of A. viscosus T14VJ1, all mice became infected. A cell‐mediated response to the bacteria was detected only in the low‐dose inoculated animals, and only the low‐dose mice developed bone loss. No serum antibody to the bacteria was detected in any animal. The response to the bacteria was detected in the cervical lymph nodes, which are the draining lymph nodes for the gingival tissue. The results suggest that the development of an immune response to the periodontal pathogen, A. viscosus T14V, correlated with bone loss in super‐infected mice.
Immunoelectron microscopic studies of Actinomyces viscosus
Authors: Berthold P. , Lai C.‐H. , Listgarten M. A. 
Published: July 2006

Optimal conditions for labelling Actinomyces viscosus (T14V) in thin sections by an indirect immunoperoxidase technique are described. The influence of several fixatives on the degree of labelling of bacterial cells was tested in pure cultures and in dental plaques. Some pure cultures were also processed without prior fixation. The effect of different incubation conditions on the degree of labelling was evaluated in pure cultures. The optimal labelling conditions included fixation with paraformaldehyde (4%) plus glutaraldehyde (0.25%), incubation with highly diluted rabbit anti‐T14V γglobulin for 24 hours at 4°C, followed by incubation with diluted sheep anti‐rabbit IgG conjugated to horseradish peroxidase, and subsequent histochemical visualization of the peroxidase. Optimal labelling conditions were used to check for cross‐reactions between the anti‐T14V γ‐globulin and some common oral bacteria. The well‐known cross‐reaction with Actinomyces naeslundii was noted, as well as a slight cross‐reaction with Bacterionema matruchotii.Optimal conditions were used for labelling sections of dental plaques. Wide variations were observed in the number of labelled cells. Cells labelled with anti‐T14V γ‐globulin were unlabelled when consecutive sections of these cells were treated with control normal rabbit serum γ‐globulin or anti‐Streptococcus mutansγglobulin. Cells labelled with anti T14V γglobulin tended to be cocco‐bacillary in shape in the superficial layers of plaque. The deeper layers exhibited more filamentous forms. These observations are compatible with the known pleomorphism of A. viscosus in vitro.
Attachment of periodontal ligament fibroblasts to the extracellular matrix in the squirrel monkey
Authors: Garant Philias R. , Cho Moon‐Il , Cullen Mary Rose 
Published: July 2006

Fibroblasts of the transseptal fiber region of the periodontal ligament contain well developed bundles of microfilaments or stress fibers. The stress fibers are made up of numerous parallel and closely packed cytoplasmic filaments approximately 6 nm wide. These intra‐cellular stress fibers appear to be connected to and colinear with extracellular non‐striated microfibrils. The junction occurs at a juxta‐membrane dense patch called the fibronexus (Singer 1979).Similar associations of cytoplasmic microfilament bundles and the attachment protein fibronectin have been shown by other investigators to be necessary for cell attachment to substrata and oriented cell migration in fibroblasts cultured in vitro.
Systemic immune response to oral colonization
Authors: Fitzgerald John E. , Birdsell Dale C. 
Published: July 2006

The principal aim of this work was to analyze the host systemic immune response to an oral infection of A. viscosus T14V. Previous work bad established a Balb/c mouse model for A. viscosus T14V oral infection. Animals were infected and the splenocyte response to A. viscosus T14V antigens, LPS, and Con A were assessed in the lymphoblast assay. Splenocytes from mice infected with A. viscosus T14V exhibited an altered response pattern to the antigens and mitogens. The responses were enhanced or suppressed when compared to the uninfected control splenocyte response. The effluent celis from a nylon wool column were unresponsive to A. viscosus antigens but LPS did respond to Con A. This response pattern was true for splenocytes from infected and uninfected animals.These results suggest that A. viscosus T14V is a potent immunomodulater when analyzed within the Balb/c mouse model system.
Collagenolytic activity associated with Bacteroides species and Actinobacillus actinomycetemcomitans
Authors: Robertson P. B. , Lantz M. , Marucha P. T. , Kornman K. S. , Trummel C. L. , Holt S. C. 
Published: July 2006

Collagenolytic activity was assessed in a variety of microorganisms with particular emphasis on members of the indigenous oral flora. Organisms were grown in complete and peptide depleted basal anaerobic broth. Cell sonicates and media preparations were assayed for collagenolytic activity using 14C‐labelled collagen in solution and as fibrils. Assay reaction products were evaluated by acrylamide gel electrophoresis.All tested species of Bacteroides, including B. gingivalis, B, melaninogenicus ss. melaninogenicus and intermedius, B. capillus, B. oris, B. thetaiotaomicron, and B. fragilis produced collagenase which was primarily associated with the cell fraction. Collagenolytic activity was also observed in both media and cell sonicates of Actinobacillus actinomycetemcomitans, Strain 511. The Bacteroides and Actinobacillus enzymes were heat labile, inhibited by EDTA and human serum. Enzyme activity appeared to be enhanced when these organisms were grown in peptide depleted medium. Collagenase production by tested species of Bacteroides and A. actinomycetemcomitans (511) was unique among other members of the oral microflora including species of Fusobacterium, Actinomyces, Capnocylophaga, and Selenomonas, which did not demonstrate collagenolytic activity under the same cultural conditions.
Effects of colchicine on periodontal ligament fibroblasts of the mouse
Authors: Cho Moon Il , Garant Philias R. 
Published: July 2006

The effects of colchicine administration on the ultrastructure aad function of periodontal ligament fibroblasts was studied in young mice as a further attempt to document the microtubule‐dependent nature of collagen secretory granule translocation.Disruption of the normal appearance of the Golgi complex was an early response to colchicine administration. This change was visible at the light microscopic level. At the electron microscopic level it was observed that Golgi saccules were dispersed and that Golgi cisternae were shorter and reduced in number. Microtubules were absent. Dense granules accumulated in a juxtanuclear region of cytoplasm previously occupied by the normal Golgi complex. Lipid droplets and autophagosomes were increased in number. Intermediate filaments (10 nm diameter) formed perinuclear fascicles several hours after colchicine treatment.These results as well as the recently published report (Cho & Garant 1981d) support the concept that microtubules play an important role in the normal organization of the Golgi complex and in the translocation of secretory granules to the fibroblast cell surface.
Quantitative analysis of connective tissue resorption in the supra‐alveolar region of the mouse incisor ligament
Authors: Schellens J. P. M. , Everts V. , Beertsen W. 
Published: July 2006

During eruption of the mouse incisor part of the periodontal ligament moves along with the tooth in the occlusal direction and is degraded in the supra‐alveolar region.In the present study stereologic analysis at the ultrastructural level has shown that significant reduction of the amount of extracellular collagen is confined to the most occlusal region of the ligament, just apically to the functional epithelium. In connection herewith a relatively high amount of homogeneous material of moderate electron density was found in the intercellular space, suggesting a process of extracellular collagen breakdown near the epithelium‐connective tissue interface.With respect to the distribution of collagen phagocytosis by fibroblasts, it appeared that the volume density of cytoplasmic vacuoles containing collagen fibrils was considerably higher in the supra‐alveolar region of the ligament than in its subcrestal part, particularly in the zone along the tooth surface. This phenomenon is interpreted as being indicative of increased phagocytic activity of fibroblasts leading to the detachment of the periodontal ligament from the cemeatum before it enters the region of final degradation near the apical termination of the junctional epithelium.In an attempt to identify the cells involved in the degradation of (fragments of) periodontal fibroblasts in the supra‐alveolar region, periodontal ligament cells were labelled with tritiated thymidine at their site of origin. By means of both autoradiography and electron microscopy, it was shown that, following the arrival of Jabelled fibroblasts in the supra‐alveolar region, at least part of the degradation of cellular constituents is accomplished via a process of heterophagocytosis among fibroblasts.
Immunological and metabolical studies in two siblings with Papillon‐Lefevre syndrome
Authors: Lyberg Torstein 
Published: July 2006

Two cases of typical Papillon‐Lefevre syndrome in one family were reported. Neither patient showed evidence of systemic disease as assessed by the medical history and a battery of clinical laboratory tests including a screening system for the detection of inborn errors of metabolism.A survey of the patients’ immunological status, including lymphocyte transformation tests using mitogens and polymorphonuclear leukocyte chemoiaxis studies, gave no indication of disturbances in immunological functions and host defense mechanisms. Possible pathogenetic mechanisms are discussed.
Microscopical evaluation of the microflora in relation to necrotizing ulcerative gingivitis in the beagle dog
Authors: Mikx F. H. M. , van Campen G. J. 
Published: July 2006

The microflora associated with necrotizing ulcerative gingivitis (NUG) in beagle dogs was investigated in three comparative studies. In the first study beagle dogs were involved harboring different stages of NUG; in the second and third studies the NUG lesions were induced by topical application of debris from a NUG lesion to the gingiva of dogs which had been pretreated with Kenacort A40R.The microorganisms of diseased and NUG free sites were compared by microscopy in gram‐stained preparations of supra‐ and subgingival samples. Most bacterial types were observed in all dogs, in diseased and NUG free sites. Distinct quantitative differences were observed for the intermediate spirochetes in the supra‐ and subgingival samples of the diseased sites. The other bacterial types were observed in variable numbers. The fusiforms were found in higher numbers in the subgingival samples of the NUG free animals.A spirillum not described previously was observed especially in relation to inoculated and diseased dogs.It is concluded that the induction of transmissible lesions in beagle dogs offers the possibility for studying the microbial and host factors related to NUG in an animal model: further investigations will aim at the occurrence of spirochetes and spirillae in relation to necrotizing ulcerating gingivitis.
Mucopolysaccharide localization in gingival epithelium Factors affecting biosynthesis of sulphated proteoglycans in organ cultures of gingival epithelium
Authors: Wiebkin and Ole W. , Thonard John C. 
Published: July 2006

The effect of extraneous hyaluronidase, trypsin, hyaluronic acid, chrondroitin sulphate, and commercial heparin on the synthesis and secretion of proteoglycans (mucopolysaccharides) by gingival epithelium in short term incubations was investigated by autoradiography. Small pieces of human gingivae were incubated at 37°C in tissue culture medium (T.C. 199) for 75 min. The first 15 min incubation included a “pulse” of (35S)‐sulphate, after which the radioactive incorporation was “chased” in radioactive free medium. Cryostat sections of these pieces were cut, air dried, slide fixed with cetylpyridinium chloride, and prepared for autoradiography. The effect of the various additives in the “pulse” or the “chase” incubations on the autoradiographic localization of incorporated (35S)‐sulphate in the epithelium was noted.The responses by the epithelium to the enzymes hyaluronidase and trypsin were different. The former caused marked tissue disruption, probably due in part to degradation of the ground substance. Synthesis and secretion of sulphated macromolecules were evident when the lower concentrations of hyaluronidase were used. Tissue disruption appeared to be less severe. Trypsin in the medium of the gingival incubations appeared to cause both metabolic and secretory disruption. Both the sulphated polyanions, chrondroitin sulphate and heparin, when added to gingival incubations, showed inhibition of localization of (35S)‐sulphate label inlercellularly. Chrondroitin sulphate included in the “chase” incubations alone resulted in the inhibition, while only low concentrations of heparin caused any inhibition. These latter data were curious. The interpretations of a comparison of the data from “pulse” and “chase” additions of the non‐sulphated hyaluronic acid imply that there was an initial inhibitory effect on secretion which in turn resulted in a subsequent regulation of synthesis of the intercellular sulphated macromolecules. These data and those derived from other tissues such as endothelium, cartilage, and chondrocyte cultures are briefly contrasted.
Loss of connective tissue attachment in the marginal periodontium of the mouse following blockage of eruption
Authors: Beertsen Wol'ter , Everts Vincent , Niehof Anneke , Bruins Hubert 
Published: July 2006

In an attempt to investigate which factors are involved in modulating the degradation of periodontal ligament carried into the supra‐alveolar region during the eruption of continuously growing teeth, the lower right incisor of the mouse was restrained from erupting by pinning it to its alveolar process. Animals were killed at time intervals varying from one hour up to nine months after pinning and their lower jaws processed for microscopic examination and histometric measurements.It was observed that, following blockage of eruption, progressive loss of connective tissue attachment occurred in the marginal periodontium throughout the entire experimental period. Loss of attachment and concomitant apical migration of the junctional epithelium apparently were neither related to eruption nor to plaque‐related inflammatory changes. These regressive features were not seen, atleast not to the same extent, in a comparable experiment involving molar teeth which are not subject to a rapid continuous eruption. Although in the latter teeth some lime‐related loss of connective tissue attachment was noted, its overall rate was, on the average, less than one fifth of that calculated for the pinned incisors.It is concluded that changes of the attachment level in the marginal periodontium of the incisor are caused by local intrinsic factors possibly connected with epithelium‐connective tissue interactions near the apical termination of the junctional epithelium.
An ultrastructural quantitative study of the significance of microbial multiplication during early dental plaque growth
Authors: Brecx Michel , Theilade Jørgen , Attström Rolf 
Published: July 2006

Plaque growth may be a result of proliferation of bacteria already present on the teeth and/or of a continuous deposition of additional salivary bacteria. The purpose of this investigation was to study the relative significance of these two mechanisms.During 4, 8, or 24 hours, plaque was allowed to form on plastic films placed on the buccal surface of the premolar 14 of subjects with healthy gingiva. In addition plastic films were used to collect plaque for an initial 4 hour period after which a filter was applied to prevent further bacterial aggregation to the deposits. The filter‐covered plastic films remained in situ for another 4 or 20 hours. After removal, the samples were processed for electron microscopy.After 4 hours, the plastic films were covered by a surface coating of an acellular material in or on which bacteria, epithelial cells, and leukocytes were observed. The 8‐hour samples exhibited the same general morphology, but contained more cellular components. After 24 hours, the plaque consisted mainly of a multilayer of bacteria. The 4‐hour samples which remained in the mouth for an additional 4‐hour period covered by a filter resembled the 8‐hour samples. Furthermore, the samples which were covered by the filter after 4 hours and allowed to remain for another 20 hours in the mouth were very similar to the 24‐hour samples.Finally, the number of bacteria present in a specified area in the section along the plastic film adjacent to the gingival margin was counted in one section from each sample. These data indicated that the number of bacteria had increased between 4 and 8 hours, but no difference was noted between the number of bacteria originating from the 8‐hour samples with or without filter. For the period between 4 and 24 hours, an obvious increase in bacterial counts was ascertained.The results indicate that proliferation of bacteria already present on the teeth accounts for the major part of the microbial mass increase during early plaque formation, and that the mean generation time is shorter during the first 8 hours (1–2 hours) than during the following 16 hours (3–7 hours).
Statistical analyses of microbial counts of dental plaque
Authors: Socransky S. S. , Haffajee A. D. , Tanner A. C. R. 
Published: July 2006

Samples of bacterial plaque were removed from the mesial surfaces of the upper canine, and upper and lower first molars from 20 young adult subjects with gingivitis but without attachment loss. Absolute counts and proportions of 23 categories of microorganisms were enumerated by darkfield microscopy and on selective and elective media. The differences in means of absolute counts of each microbial group on the tooth surfaces were compared by one‐ and two‐way analysis of variance using untransformed, log and square root transformed values. Data were compared with zero values or with zero values replaced with a minimum threshold of detection values of 105 for microscopic counts and 103 for cultural counts. The untransformed and transformed data with and without minimum thresholds replacing zero were tested for conformity to a normal distribution. Differences in counts of each microbial group on the different tooth surfaces were sought by the nonparametric Kruskal‐Wallis one‐way analysis of variance and the Friedman two‐way analysis of variance. Differences in percentages of each microbial group were also sought using the same analyses on untransformed and arc sine transformed percentages.None of the untransformed absolute counts conformed to a normal distribution. Log transformation, particularly with minimum threshold values replacing zero, was more successful in fitting the data to a normal distribution than square root transformation. However, few groups conformed to a normal distribution after either transformation. Percentages with or without arc sine transformation in most instances were not normally distributed. Substitution of minimum thresholds for zero values did not markedly alter significance testing, but did help to decrease confidence intervals of the means, particularly of log transformed counts. Significant differences revealed by the nonparametric analyses of absolute counts were most similar to one‐ and two‐way ANOVA of log transformed absolute counts. The use of nonparametric analyses for microbial counts is recommended because of the variability of the count data and the difficulties in interpreting zero values and in transforming the data to a normal distribution.