bluuebunny/crossref_metadata_2025 huggingface dataset:
The response of human sulcular leucocytes to a chemotactic challenge
Authors: Golub L. M. , Iacono V. J. , Nicoll G. , Ramamurthy N. , Kaslick R. S.
Published: July 2006

We monitored the in vivo response of human and rat crevicular leucocytes (CL) and fluid (CF) to a chemical challenge in an attempt to develop an in vivo chemotaxis assay. The mesial crevices of #21 and #22 of male dental students (mean GI = 0; crevice depth = 2.3 mm) were washed and air dried. The baseline values for CL (#num;21) and CF (#22) were recorded. CL were collected in 10 μI washes of the crevice and an aliquot immediately counted in a hemacytometer. CF was collected on filter paper strips and measured with a fluid meter. Casein, a nutrient and a standard in vitro chemo‐attractant was applied with a calibrated wire loop into each crevice. CL and CF were monitored 15 min later and at 5 min intervals up to 45 min. CL and CF peaked approximately 30 min after the casein challenge; both parameters returned to baseline rapidly thereafter. In rats, a dose‐response was obtained when concentrations of 0.01–4.0 mg casein/ml were applied to the gingival crevice. The maximum response of CL and CF occurred at 2.0 mg/ml. The application of buffer alone or Fab protein, which lacks chemotactic activity, produced no rise in CL and CF. We suggest that this crevicular technique can be used to monitor the in vivo response of subjects with defects in leucocyte chemotaxis.
Peripheral blood leucocytes with receptors for extracts of dental plaque
Authors: Walker D. M. , Hardy G.
Published: July 2006

The percentage of peripheral blood leucocytes with receptors for dental plaque has been determined with a rosetting assay. Patients with periodontal disease had a significantly greater mean fraction of leucocytes with receptors for a plaque extract than could be detected in leucocytes from healthy subjects. The percentage of plaque binding leucocytes was dependent upon the plaque concentrations used to coat the indicator sheep erythrocytes.

Attempts to demonstrate the receptors directly by pre‐incubation of the leucocytes with high concentrations of plaque were unsuccessful in that subsequent rosette formation with plaque coated sheep erythrocytes was not inhibited.

It is suggested that both antigen binding cells and mitogen binding cells are detected by the present method in proportions dependent upon the plaque concentration employed.

If tolerance occurs to plaque in advanced periodontal disease, it is not due to a reduction in the number of specific antigen binding cells.
Bone resorbing activity of gingiva from beagle dogs following metronidazole and indomethacin therapy
Authors: Nuki K. , Soskolne W. A. , Raisz L. G. , Kornman K.S. , Alander C.
Published: July 2006

Twenty‐four beagle dogs were divided into three groups of eight dogs each. Periodontitis was induced in three of the denial quadrants of each dog using wire ligatures while one quadrant was not ligaled and was kept cleaned. One group of dogs received no additional treatment, one group received systemic metronidazole and the third group received systemic indomethacin. The in vitro bone resorbing activity of extracts from freeze dried gingiva from the groups was compared.

Extracts of gingiva from ligaled teeth produced significant bone resorption. Metronidazole treatment suppressed this ligature‐induced bone resorbing activity while indomethacin had no effect. Extracts from gingiva from around clean non‐ligated teeth had somewhat less activity than extracts from gingiva of ligaled teeth, although some significant resorption remained in all treatment groups. Bacterial cultures from melronidazoletreated groups showed a change from a predominantly Gram negative obligatory anerobic flora (B. assacharolyticus), to one predominated by Gram negative, facultative anaerobes (Capnocytophaga and Campylobacter). It was concluded that metronidazole suppressed bone resorbing activity by inducing a change in the flora of the gingival crevice.
Interrelation between alveolar bone and periodontal ligament repair after replantation of mature permanent incisors in monkeys
Authors: Andreasen J. O.
Published: July 2006

Interrelation between alveolar bone and periodontal ligament repair was studied in green Vervet monkeys. Maxillary central incisors were extracted. The storage medium for the extracted teeth was saline in an 18 min. extra‐alveolar group and dry storage in a 120 min. extra‐alveolar group. In the experimental groups, the labial bone plate was removed surgically and the teeth replanted. In the control groups, teeth with similar extra‐alveolar periods were replanted into sockets with intact labial bone, The animals were sacrificed 8 weeks after replantation and the replanted teeth examined histometrically. Root resorplion and the position of the labial bone in relation to the cemento‐enamel junction were registered for each tooth. A significant relationship was found between the extent of labial bone repair and the extra‐alveolar period. Thus, teeth with I8 min. extra‐alveolar period showed almost complete repair of the labial bone plate, whereas teeth with an extra‐alveolar period of 120 min. showed a mean position of labial bone 3.7 mm from the pocket epithelium. The extent of root resorption was influenced by the extra‐alveolar period alone and not by the presence or absence of alveolar bone. It is concluded that a vital periodontal ligament upon replanted mature teeth is able to induce the formation of new alveolar bone.
The predominant cultivable subgingival flora of beagle dogs following ligature placement and metronidazole therapy
Authors: Kornman K. S. , Siegrlst B. , Soskolne W. A. , Nukl K.
Published: July 2006

Ligature‐induced periodontitis was evaluated microbiologically in 8 beagle dogs. Gingival health was established by repeated cleaning. At day 0 subgingival plaque was sampled from individual sites in two quadrants. All teeth in one quadrant were then ligated at the CEJ, and the other quadrant served as a non‐ligated control which was cleaned three times each week. At day 14, four dogs were given metronidazole for seven days. Plaque was cultured anaerobically on nonselcctive media, and the predominant cultivable flora was characterized. At day 0 Gram‐negative facultative rods represented 56.8 % of the flora. with motile and surface translocating organisms predominating. At day 14 Bacteroides asaccharolyticus, including catalase positive B.asaccharolyticus‐like organisms, increased at ligated sites to 34.7 % of the cultivable flora. After metronidazole therapy the total bacterial count decreased, and Gram‐negative anaerobic rods became non‐detectable. Gram negative facultative bacteria which were motile or surface translocating represented 52.7 % of the cultivable flora after metronidazole treatment.

In the beagle dog ligature placement was associated with a shift in the flora from Gram‐negative facultative rods to Gram‐negative anaerobic rods. Metronidazole treatment reduced the total cultivable flora and selectively reversed the microflora shifts which followed ligature placement.
The progress of the periodontal syndrome in the rice rat
Authors: Gotcher J. E. , Jee W. S. S.
Published: July 2006

Several morphometric and cellular parameters were studied in the rice rat (Oryzomys palustris). When fed a soft, high carbohydrate diet, a severe periodontal disease occurred, with significant alterations in the morphometric and cellular endpoints observed. Weaned animals were placed on a high carbohydrate diet for periods of 6, 12 or 18 weeks. There was a linear, rapid loss of bone by 18 weeks, approaching a 75 % loss of original bone. Vascular spaces decreased as the remaining connective tissue became fibrotic in character. The percentage of the interdental test site which was destroyed by periodontal disease increased dramatically over the time of the experiment. The numbers of fibroblasts per mm of bone surface increased slightly at the 18 week period; osteoblasts were unchanged at any period. The numbers of osteoclast nuclei rose dramatically by 12 weeks, and these cell nuclei remained at increased levels at 18 weeks. Also, the numbers of inflammatory cells residing at the bone surface increased greatly by 18 weeks time. Finally, the numbers of 3H‐TdR labeled periodontal ligament (PDL) fibroblasts increased significantly at both 12 and 18 weeks time. These cellular changes and their relation to the bone loss due to periodontal disease are discussed.
Influence of cell cycle on collagen synthesis by human gingival fibroblasts
Authors: Ko S. David , Narayanan A. Sampath , Page RoyC.
Published: July 2006

The effect of cell cycle stages on collagen and protein synthesis by human gingival fibroblasts was investigated. The fibroblasts were synchronized by depriving them of serum for 48 hours and then activating them to divide by adding 10 per cent fetal calf serum. At various time points, the cells were pulse labeled with radioactive proline, and protein and collagen synthesis were measured. Proteins were quantitated by total proline incorporation and collagen was assayed by digesting it with purified bacterial collagenase. Protein synthesis increased with time and reached maximal levels at and after 24 hours, the time of peak DNA synthesis. The proportion of collagen synthesized also increased, and it reached maximum values after 33 hours. The levels of transport of proline into the cell did not parallel the protein synthesis. Confluent and nonconfluem cells gave similar results. The ratio of collagen type I to type III collagen did not significantly vary at any time and no new collagens were detected.
Collagen degradation by human gingival fibroblasts
Authors: Yamasaki Akira , Rose George G. , Mahan Charles J.
Published: July 2006

An electron microscopic survey and stereological analysis were made of the lamina propria of human gingival tissues from 8 patients with periodontitis and 6 patients clinically free of pathology (normal). The connective tissue was classified and divided into Zones A, B, and C, according to their collagen content, fibroblastic status (active or inactive), and numbers of inflammatory cells. Fibroblastic phagocytosis of collagen was most prominent in relatively stable areas (Zone A) where the collagen content was high, fibroblasts were classified as inactive (resting), and there were no inflammatory cells. Active (synthesizing) fibroblasts were conspicuous in Zone B, where intercollagenous spaces were wide and mononuclear cells occurred. Phagocytosis of collagen in the human gingiva was found to be a minor function of fibroblasts in Zone B and the highly inflamed Zone C.
The effects of bacterial sonicates on human keratinizing stratified squamous epithelium in vitro
Authors: Kamen P. R.
Published: July 2006

Direct cytotoxicity of plaque is believed to play a role in the soft tissue destruction observed in periodontal disease. This property has been demonstrated in vitro on cell lines but appears to be dependent upon the target cell used and the plaque organism being tested. The purpose of this investigation was to determine the effects of bacterial products on growth of keratinized stratified squamous epithelium maintained in vitro. Morphological features of these cultures closely resembled normal epidermis. Sterile sonicates of the periodontal pathogenesBacieroides asaccharolyticusandActinomyces, naeslundiiwere diluted to equal protein concentrations and added lo keratinocyte cultures. TheBacteroidessonicate caused up to 97 % inhibition of labelled thymidine uptake of cultured keratinocytes while the peak inhibition of theActinomycessonicate was only 39 % of untreated controls. These results indicate that products ofB.asaccharolyticuswere more inhibitory to the growth of cultured keratinocytes than products ofA. naes lundii.and that keratinocyte cultures make a useful model for investigation of the interactions between periodontal pathogens and differentiating epidermal cells.
Cyclic nucleotide content in gingival tissue of smokers and non‐smokers
Authors: Hedin C. A. , Ronquist G. , Forsberg O.
Published: July 2006

The total amount of cAMP and cGMP was determined in gingival tissue of smokers and non‐smokers. The mean gingival tissue content from 56 patients was 1.80 pmol cAMP/mg protein and 0.56 pmol cGMP/mg protein. There was no significant difference in nucleotide levels as between smokers and non‐smokers. Heavy smokers (> 15 cig/day, x̄= 19.7). however, were found to have significantly elevated nucleotide levels as compared to moderate smokers (≤ 15 cig/day, x̄= 6.8). Smokers also had a significantly lower gingival exudate flow as compared to non‐smokers. These findings suggest that tobacco smoking may change the cellular metabolism in human gingival tissue.
Bone induction in vitro
Authors: Rose George G. , Yamasaki Akira , Mahan Charles J.
Published: July 2006

A human gingival fibroblast cell line was cultured on bovine fibrillar collagen films and under transparent regenerated cellulose filters (cut off 70,000 M.W.) in multiple chambers of a circumfusion system. The cultures were in apposition with 0.5 mm‐thick wafers of demineralized human tooth. The fibroblasts grew up and around the wafers, and after one month the electron micrographs showed deposits of extracellular fibrils and matrix vesicles on the tooth matrix. In some areas near the tooth matrix clusters of apatite‐like crystals appeared in the extracellular fibrils after two months of cultivation.
The microbiology of ligature‐induced periodontitis in the cynomolgus monkey
Authors: Kornman K. S. , Holt S. C. , Robertson P. B.
Published: July 2006

The cultivable subgingival microflora in the cynomolgus monkey, Macaca fascicularis, was monitored during the ligature‐induced progression of naturally occurring gingivitis to periodontitis. Clinical and microbiological observations were divided into four stages. Stage I, prior to ligature placement, was characterized clinically by chronic generalized gingivitis and microbiologically by Gram‐positive cocci and rods with B. melaninogenicus ss. intermedius the dominant Gram‐negative organism. Stage II, 1 to 3 weeks following ligature placement, exhibited slightly greater gingival inflammation but no clinical evidence of attachment loss. The subgingival flora showed a significant increase in motile and surface translocating Gram‐negative rods, primarily Capnocytophaga species and Campylobacter sputorum. Stage III, 4 to 7 weeks following ligature placement, revealed increased pocket depth and radiographic evidence of alveolar bone loss. This stage was characterized by a Gram‐negative anaerobic flora with B. asaccharolyticus as the dominant cultivable organism. Stage IV encompassed the remainder of the experimental period, 8 to 17 weeks, during which time no further change in the clinical parameters occurred and levels of B. asaccharolyticus decreased.

The subgingival microflora of ligature induced periodontitis in Macaca fascicularis closely resembled that reported for human periodontal disease and the episodic clinical pattern of attachment loss was associated with levels of Gram‐negative anaerobes, primarily B. asaccharolyticus.
Immunological studies of young adults with severe periodontitis
Authors: Ranney R. R. , Ruddy S. , Tew J. G. , Welshimer H. J. , Palcanis K. G. , Segreti A.
Published: July 2006

The objective of this study was to determine whether young adults (19–30 yrs.) with severe, generalized periodontal destruction differed from an age matched population with a healthy periodontium when compared by a thorough medical evaluation and/or an evaluation of humoral immunoglobulins and complement levels. The medical laboratory testing included BP, EKG, chest film, VDRL, urinalysis, hematology, blood chemistry, GTT, and a physical examination. The evaluations of immunoglobulins and complement included levels of serum and salivary IgG, IgA, IgM and 8 proteins of the classical and alternative complement pathway and levels of serum antibody to a panel of bacteria. The two groups were very similar in results of medical evaluations, antibody, complement, properdin, and immunoglobulin levels in most comparisons. The periodontally diseased group did have higher IgG levels and a tendency for higher IgA in saliva, probably due to gingival fluid contributing to saliva, including production of IgG locally in the gingiva. There was also a tendency for higher IgG in serum of the diseased group, resulting from more individuals in that group having elevated levels than in the healthy group. The mean levels of both
Collagenase and neutral metallo‐proteinase activity in xtracts of inflamed human gingiva
Authors: Veli‐Jukka Uitto , Appelgren Rolf , Robinson Peter J.
Published: July 2006

Human gingiva was found to contain neutral proteolytic enzymes that degrade native and denatured collagen, and azocoll, a substrate for non‐specific proteinases. The best enzyme recovery was obtained when an insoluble gingival homogenate was extracted at 40°C in the presence of 0.1 M CaCl2. The proteinases were found to exist in the extracts mostly in a latent form that could be activated by compounds reacting with sulfhydryl groups of proteins. Enzyme inhibitor studies showed that all three enzymes belong to the group of metallo‐proteinases. In gel filtration chromatography the enzyme activity degrading denatured collagen was separated from the two other proteinase activities. When the specific collagenase activity and the nonspecific proteinase activity were compared with Gingival Index, it was found that the enzyme activities were significantly higher in gingival samples that showed clear signs of inflammation than in clinically non‐inflamed samples.
The relationship between soft tissue attachment, epithelial downgrowth and surface porosity
Authors: Squier C. A. , Collins P.
Published: July 2006

Millipore filters with pore sizes ranging from 0.025 μm to 8.0 μm were implanted in the backskin of pigs for periods up to 8 weeks. Measurements of the rate of epithelial migration along the filters showed an inverse relationship with pore size although the extent of migration was significantly less along filters with pore sizes of 3‐ μm and above than along those with smaller pore sizes. Histological examination revealed a difference in the extent of connective tissue infiltration which corresponded to the differences in the rate of migration; filters of pore size 3 μm or more were extensively infiltrated with cell and tissue elements whereas there was little infiltration of filters of 1 μm pore size and none of smaller pore size filters. It is suggested that 3 μm is the minimum pore size that permits connective tissue penetration into the filter and that when infiltration does occur the resulting soft tissue attachment markedly restricts the extent of epithelial downgrowth. These results support therapeutic attempts to modify the cemental surface and thereby facilitate soft tissue reattachment to the tooth.
Mucopolysaccharide localization in gingival epithelium
Authors: Wiebkin Ole W. , Thonard John C.
Published: July 2006

Short incubations, at 37°C, of small freshly excised pieces of healthy human gingivae iancorporated [35S]‐sulphate and [3H]‐acetate into macromolecular material which could be precipitated intercellularly in the epithelium. Following radioactively pulse‐chased incubations, such localization was observed by autoradiography on cryostat histological sections fixed in cetylpyridinium chloride. Critical electrolyte salt concentration elution indicated that most of the intercellular material was soluble in 0.63M‐MgCl2, and any material which remained was intracellular. In vitro and in vivo incorporation studies were compared. These data corroborate biochemical studies (Wiebkin, Bartold & Thonard 1979) together with other histochemical observations that proteoglycans (mucopolysaccharides) are a major intercellular component of human gingival epithelium. Molecular conformation and the relatively rapid synthesis and secretion rate for this class of epithelial macromolecule may explain the lack of susceptibility of this material in the intercellular site, both to degradation by some specific enzymes previously reported and to elution with critical salt concentrations from cationic detergent precipitates.

The method described, together with in vivo incorporation studies, provides a useful technique for studying direct effects of some microenvironmental influences on gingival epithelium.
The effect of subclinical ascorbate deficiency on periodontal health in nonhuman primates
Authors: Alvares Olav , Altman Leonard C. , Springmeyer Steven , Ensign Wayne , Jacobson Kerry
Published: July 2006

The aim of this study was to evaluate the effects of chronic subclinical ascorbic acid deficiency on periodontal health in a nonhuman primate model. Young adult Macaca fascicularis monkeys were fed an ascorbic acid free diet for nine weeks followed by a diet with a suboptimal level of ascorbic acid for an additional sixteen weeks. During the 25‐week period, a pair fed control group was fed a nutritionally adequate diet in amounts equivalent to that consumed by the experimental group. From the second week onward, whole blood ascorbic acid levels in the experimental animals but not in pair fed controls were significantly reduced. Experimental animals did not develop clinical signs of ascorbate deficiency, and there was little evidence of spontaneous gingivitis or periodontitis in either group between weeks 0 and 23. At week 23, plaque‐associated periodontitis was experimentally induced to evaluate the response of the periodontal tissues to the underlying subclinical ascorbate deficiency. Gingival index scores and pocket depth measurements were significantly greater in the ascorbate deficient animals than in controls. Preliminary studies of leukocyte function suggested that this susceptibility to periodontitis might be related to impaired polymorphonuclear leukocyte chemotaxis and phagocytosis. This study indicates that the periodontium is vulnerable to chronic inflammation as a consequence of subclinical ascorbic acid deficiency.
Tetracycline treatment of periodontal disease in the beagle dog
Authors: Williams R. C. , Leone C. W. , Jeffcoat M. K. , Scott E. R. , Goldhaber P.
Published: July 2006

Seventeen adult beagle dogs with moderate to severe periodontitis were examined at time zero and after a 6 month pretreatment period for plaque accumulation, gingival inflammation, and rate of alveolar bone loss. The dogs were then divided into three groups. One group was the untreated controls, one group received tetracycline HCl 250 mg daily, and one group received tetracycline HCl 500 mg daily. Plaque accumulation, gingival inflammation, and rate of alveolar bone loss in each group over a 12 month treatment period was compared to the pretreatment baseline values in each group.

There was no significant difference in either the mean plaque accumulation or gingival inflammation over the 12 month treatment period in the untreated control dogs or the tetracycline treated dogs. The untreated control dogs lost alveolar bone in the treatment period at a rate similar to the pretreatment period. In the dogs treated with 250 and with 500 mg tetracycline HCl there was a statistically significant decrease in the rate of alveolar bone loss in the treatment period when compared to the pretreatment period.

The findings suggest that daily tetracycline in either a 250 or 500 mg dose does not affect accumulation of bacterial plaque or severity of gingival inflammation in the beagle dogs studied. Tetracycline administration does significantly decrease the rate of alveolar bone loss in the treated animals for a 12 month period. An additional report will detail the subsequent 12 months of treatment in which tetracycline loses its ability to reduce the rate of alveolar bone loss.
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.
Intercellular junctions and the permeability barrier in the junctional epithelium
Authors: Saito Isamu , Watanabe Osamu , Kawahara Hironori , Igarashi Yuichi , Yamamura Takeo , Shimono Masaki
Published: July 2006

The morphology and distribution of intercellular junctions were studied in the clinically normal junctional epithelium of dogs by freeze‐fracture and thin sectioning. Desmosomes were found in cells of the coronal and apical regions of the junctional epithelium. The occurrence values for desmosomes were low in comparison with those of other oral epithelia. Gap junctions were also observed in cells of the junctional epithelium, often in association with desmosomes. These were usually small, their diameter varying between 0.2 and 0.7 μm. Relatively large ones were found in the cells of the coronal region. Tight junctions were observed only in the intermediate cells of the coronal region, forming small, discrete maculae occludentes. Numerous dense PTA‐positive granules were observed in the peripheral cytoplasm of the intermediate and superficial cells. In freeze‐fracture replicas, hemispherical structures were also observed at the periphery of the cytoplasm. Because of similarities in their size and location, the hemispherical structures probably correspond to the dense granules. Freeze‐fracture images such as elevated membranes seem to reveal exocytosis. The hypothesis is put forward that the dense granules are related to the physiological permeability barrier in the junctional epithelium. However, it is doubtful that the epithelium provides a complete barrier function because of the vast extent of the intercellular spaces and the sparseness of desmosomes.
Progesterone metabolism by rat oral mucosa
Authors: Ojanotko Anita , Mielityinen Helena , Harri Matti‐Pekka
Published: July 2006

The metabolism of progesterone in the oral mucosa of the rat was investigated. Homoge‐nates and mitochondrial, microsomal, and soluble fractions were obtained with differential centrifugation. The subcellular preparations were supplemented with NADPH and incubated with 14C‐progesterone for 30 min at pH 7.4 and 37°C. The metabolites were identified by column, multiple thin‐layer chromatography and radioautography and quantified with liquid scintillation counting. The subcellular preparations of female and male rat oral mucosa were found to metabolize progesterone. Differences between both sexes were detected. The metabolism was less in the male than in the female preparations. On the basis of the identified metabolites it can be concluded that the oral mucosae of both sexes contain marked 3α‐3β, and 20α‐hydroxysteroid dehydrogenase, δ4‐5α‐ and δ4‐5β‐steroid hydrogenase activities, and also small 20β‐hydroxysteroid dehydrogenase activity.
Physiological and ultrastructural characterization of a new Bacteroides species (Bacteroides capillus) isolated from severe localized periodontitis
Authors: Kornman K. S. , Holt S. C.
Published: July 2006

Strains of a new Bacteroides species were isolated from three cases of severe localized periodontitis in adults, in which the organism comprised greater than 50 % of the cultivable subgingival flora. The isolates were Gram‐negative, obligately anaerobic short rods, which required CO2 for growth. The strains were esculin‐positive, oxidase– and gelatinase‐negative, and produced acid from a variety of carbohydrates, including arabinose, xylose, raffinose, rhamnose, and cellobiose. The major acid end–products from glucose were acetic and succinic acids. The isolates all possessed an extra‐layer external to the outer membrane, as well as an extensive fibrous or hair‐like network of intensely staining, ruthenium red, and malachite green material, indicative of a glycolipid or a glycolipoprotein polymer. The physiological and ultrastructural observations are discussed in relation to other known bacteroides and show these isolates to be representative of a new Bacteroides species named Bacteroides capillus.
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.
Complement fixing activity in diseased human gingival tissues
Authors: Schonfeld Steven E. , Drury Gerald I. , Herles Susan M.
Published: July 2006

Human gingival tissue biopsies were classified as “initial or early” or “established or advanced” periodontal lesions on the basis of the histopathological criteria of Page and Schroeder (1976). They were then examined for the ability to fix complement by the anticomplement immunofluorescence technique which detects fixation of exogenously applied guinea pig complement. Complement fixation was found in association with IgG deposits (detected by immunohistochemical staining) in 80 % of the established and advanced lesion, thus suggesting that it was fixed by immune complexes or aggregated IgG. The complement fixing activity was not associated with IgA or IgM deposits. In contrast, less than 13 % of the initial and early lesions were found to contain such activity. The presence of complement fixing activity was thus found to be significantly correlated with the more advanced as opposed to the earlier stages of periodontal inflammation (p = 0.02 by Chisquare analysis).
Differences between gingivitis and periodontitis associated microbial flora in the beagle dog
Authors: S vanberg G. K. , Syed S. A. , Scott B. W.
Published: July 2006

The predominant dental plaque flora was compared between two groups of adult beagle dogs, (1) ten with gingivitis and (2) ten with advanced periodontitis. Plaque from a maxillary third premolar was cultured under strict anaerobic conditions. Specimens comprising the marginal periodontal tissues were taken at the plaque sampling site and analyzed for some histological parameters of periodontal disease. The periodontitis dogs scored significantly higher for crevice depth, length of ulcerated crevice epithelium, area of inflamed connective tissue, and loss of attachment. Supragingival periodontitis plaque had significantly higher anaerobic to aerobic ratio, proportions and CFU of esculin negative streptococci, but lower proportions of Actinomyces viscosus. Subgingival periodontitis plaque had significantly higher anaerobic to aerobic ratio, microscopic counts of spirochetes, total viable CFU, proportions and CFU of esculin negative streptococci and Fusobacterium nucieatum, as well as CPU of Bacteroides asaccharolyticus, Gram negative bacilli and coccobacilli, but significantly lower proportions of A. viscosus and unspeciated actinomycetes. The total viable CFU, proportions and CFU of esculin negative streptococci correlated with all four histological parameters of periodontal disease. The CFU of B. asaccharolyticus, bacilli, and coccobacilli correlated with the length of ulcerated crevice epithelium and loss of attachment, but F. nucleatum only with the area of inflamed connective tissue and loss of attachment.
Microbiological studies on early dento‐gingival plaque on teeth and Mylar strips in humans
Authors: Theilade Else , Theilade Jørgen , Mikkelsen Lena
Published: July 2006

The predominant cutivahle flora of 3‐ and 8‐hr‐old dento‐gingival plaque formed on a buccal tooth surface and on Mylar strips ligated to a buccal surface was studied in 6 students with healthy gingiva. Differential counts of various bacterial types were also performed by direct microscopy. In 6 other students. 1‐ and 3‐day‐old plaque was similarly studied. From each sample. 31–111 strains (a total of 2,867 strains) were characterized. Streptococci predominated at all times. Most of these were Streptococcus milior. Sfreptococcus sunguis and Streptococcus milleri. Very few Gram‐negative cocci were isolated from 3‐ and 8‐hr samples, whereas Veillonella constituted about 20 Q of the strains from 1‐ and 3‐day plaque. Gram‐positive rods increased from low proportions in most 3‐ and 8‐ hr samples to median values of 21% and 25% in 1‐ and 3‐day plaque. In 3‐ and 8hr samples all the Gram‐positive rods were facultative anaerobes (most of them Actinomyces viscosus and Actinomyes nueslundii). In 1‐ and 3‐day samples obligatdy anaerobic Grampositive rods also appeared. Gram‐negative rods were virtually absent from 3‐ and 8‐hr plaque. Ohligately anaerobic Gram‐negative rods appeared in low proportions in 1‐ and 3day samples (median 4% and 7%). Large site‐to‐site variations were found but no systematic differences between samples from Mylar and enamel surfaces.
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.
Virulence of black‐pigmented Bacteroides strains from periodontal pockets and other sites in experimentally induced skin lesions in mice
Authors: Van Steenbergen T. J. M. , Kastelein P. , Touw J. J. A. , De Graaff J.
Published: July 2006

The virulence of different black‐pigmented Bacteroides strains (BPB) was studied using monoinfections in an experimental animal model. Bacterial suspensions were injected subcutaneously in the back of mice. After four days the mice were killed and the induced inflammations were examined histologically. Bacteroides gingivalis strains, which are mostly isolated from subgingival plaque associated with adult destructive periodontitis. were characterized by inducing a spreading type of inflammation, mostly resulting in a gravity abscess or a phlegmonous abscess. Strains of Bacteroides melaranogenicus subspecies intermedius, isolated from gingivitis or periodontitis, always induced a localized abscess at the site of injection. Most Bacteroides asaccharolyticus strains, which are isolated from nonoral sites, caused a localized inflammation, and Bacteroides melaninogenicus subspecies melaninogenicus strains caused only minimal inflammation.
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.
The effect of indomethacin on alveolar bone loss in experimental periodontitis
Authors: Weaks‐Dybvig Marilyn , Sanavi Farshid , Zander Helmut , Rifkin Barry R.
Published: July 2006

This study was undertaken to determine if prostaglandins play a role in the events leading to loss of bone in the ligature model of periodontitis. Periodontitis was induced by placement of the ligatures around mandibular teeth on one side of the jaw of squirrel monkeys (Saimiri sciureus). From one day prior to ligature placement, half the animals were administered indomethacin (5 mg/kg/day), a potent inhibitor of prostaglandin synthesis. Animals were sacrificed after one and two weeks of experimental periodontitis. It was found that indomethacin treatment abolished the significant losses of alveolar bone height and bone mass seen in non‐indomethacin‐treated (NIT) animals following ligature placement. Indomethacin also depressed the large increase in osteoclast density measured at one week in the NIT animals. The results support the hypothesis that prostaglandins are an important mediator of bone loss in the ligature model of periodontitis. Evidence is also presented for the coupling of bone resorption with osteoblastic neo‐osteogenesis on both periodontal ligament and endosteal bone surfaces.
Progesterone metabolism by rat oral mucosa II. The effect of pregnancy
Authors: Ojanotko and Anita , Harri Matti‐Pekka
Published: July 2006

In order to examine the effect of pregnancy on the gingiva, the metabolism of progesterone in pregnant and non‐pregnant rats was studied. Homogenates and mitochondrial, microsomal, and soluble fractions were obtained with differential centrifugation. The subcellular preparations were supplemented with NADPH and incubated with 14C‐progesterone for 30 min at pH 7.4 and 37°C. The metabolites were identified by column and multiple thin‐layer chromatography and radioautography and quantified with liquid scintillation counting. The metabolism was significantly reduced in homogenate, mitochondrial, and microsomal incubations of oral mucosae of pregnant rats when compared to those of non‐pregnant ones. The decrease of the metabolism in the soluble fraction incubations was not statistically significant. In all subcellular preparations the activities of 20et‐and 20β‐hydroxysteroid dehydrogenases, if present, remained rather constant, but the activities of steroid hydrogenases and 3α‐ and 3β‐hydroxysteroid dehydrogenases decreased markedly. The value of these findings as a contributing factor in pregnancy gingivitis is discussed.
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.
Biosynthesis of complement components in chronically inflamed gingiva
Authors: Lally Edward T. , McArthur William P. , Baehni Pierre C.
Published: July 2006

The biosynthesis of the third and fifth components of complement in chronically inflamed gingiva is demonstrated. The technique utilized in these studies was an immunochemical detection of 14C‐labeled amino acid incorporated protein from gingival explant cultures. C3 and C5 synthesis was detected in 8 of 10 individuals with periodontal disease, while no evidence of synthesis was noted in 5 control subjects. The results indicate an even greater consumption of complement occurs in periodontal disease than has been predicted previously using serum as the sole source of complement. The local production of complement could play a role in modulating the inflammatory response in the gingiva.
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.
Localized damage to the periodontal ligament and its effect on the eruptive process of the rat incisor
Authors: Michaeli Y. , Pitaru S. , Zajicek G.
Published: July 2006

Localized thermal injury was produced in the coronal part of the rat incisor periodontal ligament (PDL). The tooth was cut off at the gingival margin and its pulp removed to a depth of 9 mm from the cut edge. An electrocautery needle was then inserted into the pulp cavity, and a current of two seconds duration was applied. The thermal injury affects primarily PDL vitality, and this is manifested by an eruption slow‐down accompanied by typical histological changes. Specimens for histological examination were obtained one, three, and seven days following treatment and compared with the sections prepared from sham operated and control incisors. The mean eruption rate of the cauterized teeth was slower by about 70 % than that in the other two groups. Histological sections of the former incisors revealed well demarcated coagulation necrosis, which was especially pronounced on the first and third post treatment days. Signs of repair in the damaged areas were observed on the seventh day following treatment. The lingual periodontal lesions were infiltrated with fibroblasts and vascular tissue. In some incisors, hard tissue deposits appeared in the tooth‐related part of the PDL. The PDL of sham operated or control animals did not exhibit any changes. These experiments demonstrate that isolated damage to the PDL retards tooth eruption, supporting the hypothesis which views the PDL as the prime motor pulling the erupting incisor outward.