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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 157 (1997), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: We report here that Streptomyces coelicolor A3(2) produces at least seven butyrolactone autoregulators: two of the IM-2 type, four virginiae butanolide type, and one A-factor type. The most abundant one corresponds to virginiae butanolide-C9 having a C2 side chain of nine carbons. Model butyrolactone compounds as well as extracts of S. coelicolor mycelia showed clear induction of morphological differentiation, implying that S. coelicolor A3(2) probably possessed butyrolactone-type autoregulator(s) controlling the morphological differentiation.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 31 (1996), S. 0 
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Serum rheumatoid factor (RF) level and peritoneal and splenic CD5+B (B-1) cells in mice were examined after intraperitoneal administration of purified lipopolysaccharides (LPS) from oral periodontopathic bacteria; Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum and Capnocytophaga ochracea. F. nucleatum and C. ochracea LPS induced higher levels of serum IgM- and IgG-RF, while P. gingivalis LPS showed the least induction. In addition, wet weights of spleen and serum IgM and IgG concentration were markedly increased in F. nucleatum LPS injected group. On the other hand, the proportion of CD5+ B cells to lymphocytes in the peritoneal cavity and spleen did not increase. The reason for this was not clear but conventional B cells (CD5+ B cells) might increase more rapidly with splenic enlargement than CD5+ B cells. These results suggested that RF induced by bacterial LPS may modulate immune responses against bacteria and plays an important role for defence and destruction of periodontal tissue.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 31 (1996), S. 0 
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Using the method of reconstitution of nude mice with T cells, we examined the effects of T cell on alveolar bone resorption induced by repeated injections of Escherichia coli endotoxin into periodontal tissue. Three mice groups (normal, nude and T cell reconstituted nude mice) were used. Endotoxin derived from E. coli was repeatedly injected into the gingiva of the mice left mandibles every 48 h and the mice were killed on the day after the 1st, 4th, 7th, 10th, 13th and 20th injections of endotoxin. Alveolar bone resorption was examined histopathologically and histomorphometrically. Bone surfaces in contact with the osteoclast were defined as the site of active resorption and the ratios of active resorption were compared among the 3 nice groups. Consequently, no active resorption was found after the first injection of endotoxin in any group. After the 4th injection, active resorption was found in normal nice and T cell reconstituted nude mice and gradually rose with the increase in the injection frequency. In contrast, few osteoclasts were found even after the 10th injection in the nude mice. In addition, there were statistically significant differences between the normal price and nude mice after the 4th and 10th injections (p〈0.05). These findings suggested that T cell influences periodontal bone destruction induced by local administration of endotoxin during the early phases.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We have reported recently that increased expression of membrane alkaline phosphatase (ALP) activity is a phenotypical characteristic of gingival fibroblasts located in chronic inflammatory periodontal lesions. To understand the cellular properties of these cells, we isolated ALP-positive gingival fibroblasts from patients with adult periodontitis and evaluated their proliferative potential. Using an enzymatic digestion procedure, we prepared gingival cell suspensions containing ALP-positive fibroblasts without affecting their ALP activities. These cell suspensions were then subjected to 1 g sedimentation, followed by allowing cells to adhere to substrata. Using this procedure, 71.9% of isolated cells were ALP-positive. Dissociation of ALP-positive fibroblasts and contamination by non-fibroblastic cells were examined by cytochemical and immunocytochemical analyses. The proliferative capacity of ALP-positive fibroblasts in culture was assessed by monitoring the proportion of ALP-positive cells after repeated subculture passages and by labelling DNA-synthesizing cells with bromodeoxyuridine (BrdU). The proportion of ALP-positive fibroblasts decreased during cell culture passages without an apparent change in the ALP-positive phenotype. The percentage of BrdU-positive cells was significantly lower among ALP-positive than among ALP-negative fibroblasts. These results indicate that ALP-positive fibroblasts in chronic inflammatory periodontal lesions have low growth potential. We suggest that their reduced capacity to grow in vitro reflects a more differentiated state induced under inflammatory conditions in vivo.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Cystatins are protein inhibitors of cysteine proteinases, which are believed to play an important role in the pathogenesis of periodontal disease. In this study, we report a new sensitive method for the quantitative analysis of cystatin activity in a small amount of crude sample such as gingival crevicular fluid. Cystatin activity in the crude sample was determined by using active site-titrated papain, which is a cysteine proteinase from the plant Carica papaya. Crude samples usually contain endogenous cysteine proteinases. These competed with the added papain for the active sites of the cystatins. The cystatin-cysteine proteinase complex was able to be dissociated by the addition of papain. This competition and dissociation could interfere with the determination of cystatin activity, since some of the cysteine proteinases, such as cathepsin B, hydrolyzed the specific substrate for papain during titration with the papain. In order to exclude this interference and measure total cystatin activity, the crude sample must be alkalinized (pH 11.0) for 5 min at 4°C followed by 10 min at 40°C before titration with papain. The minimum detectable amount of cystatins was 20 fmol/ assay when it was calculated per mole of papain inhibitory sites. Using this method, significant levels of cystatin activity were detected in all the samples of gingival crevicular fluid taken from periodontal disease patients. These results suggest that cystatins could regulate the cysteine proteinases in gingival crevicular fluid and that this new method could be useful to clarify the role of cystatins in the pathogenesis of periodontal disease.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 22 (1987), S. 0 
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Specimens of gingiva from 78 lesions taken from 52 patients with chronic periodontitis and gingiva from clinically healthy subjects or subjects with gingivitis were obtained. The patients and control subjects were placed into three groups according to age. The numbers of IgE-bearing cells and other classes of immun-oglobulin-bearing cells were counted, and the ratios of those cells to the total numbers of infiltrating cells were determined. There was a predominance of IgG-bearing cells, followed by IgA-bearing cells; the numbers of IgM- and IgE-bearing cells were small. IgE-bearing cells were observed in gingivaI specimens with a small infiltration. In moderately and severely infiltrated lesions, IgE-bearing cells were observed most frequently in the specimens, and the ratio of IgE-bearing cells to total inflammatory cells was significantly elevated. These findings show that local IgE synthesis is highest in the gingiva of young patients with periodontitis and supports the concept that a hypersensitivity reaction mediated by IgE may play a role in periodontitis.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 32 (1997), S. 0 
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Our previous study showed that the expression of carbohydrate residues in junctional epithelium (JE) after resection is closely related to attachment and stratification along the dental root surface. However, the influence of the periodontal ligament on carbohydrate expression has still not been clarified. In this study we examined the relationship between the presence of periodontal ligament and the expression of carbohydrate residues on epithelium regenerating along root surfaces. We transplanted extracted rat molars with or without periodontal ligament tissue, repeatedly frozen and thawed teeth with ligament and demineralized teeth without ligament into the dorsal skin of rats. After 2, 3, 5, 7, 10, 14 or 21 d, dorsal cutaneous tissues containing transplanted teeth were resected, fixed, decalcified and embedded in paraffin. Serial sections were stained histochemically with the HRP-conjugated lectin. peanut agglutinin (PNA) to observe the expression of carbohydrate residues in regenerating epithelium. Histochemical observation revealed that lectin binding reactions were changed from the characteristics of skin to those of JE when the regenerating epithelium was attached and stratified along the tooth with unfrozen or frozen tissue. These results suggested that the structural formation and expression of PNA in regenerating epithelium around the root surface were influenced by not only the tooth but also by the periodontal ligament.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Different types of periodontopathic bacterial lipopolysaccharide (LPS) exert various biological activities in vitro. However, whether or not these activities also occur in vivo remains unclear. Thus the present study investigates bone resorption, as well as local IL-1α and IL-1β synthesis induced by Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis LPS in the periodontal tissue of mice. Both types of LPS were injected into mouse gingiva every 48 h and the animals were sacrificed 6 h after the 1st, 4th, 7th, 10th, 13th, 16th, 20th, or 24th injection. Bone resorption in the injected gingiva was histopathologically and histomorphometrically investigated and local concentrations of IL-1α and IL-1β were detected using an enzyme-linked immunosorbent assay. The active resorption ratio was significantly higher in the group given the 10th injection of LPS from A. actinomycetemcomitans than in the group given P. gingivalis LPS. Furthermore, A. actinomycetemcomitans LPS stimulated significantly more synthesis of IL-1α than P. gingivalis LPS after the 4th and 10th injections, and of IL-1β after the 4th, 7th, 10th, 13th, 16th and 20th injections. These results suggest that A. actinomycetemcomitans LPS is a more potent inducer of bone resorption and synthesis of IL-1α and IL-1β in the short term than P. gingivalis LPS.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 26 (1991), S. 0 
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We investigated the penetration and clearance of antigen in the rat gingiva and the antigen-specific antibody response in the draining lymph nodes. Rats were primarily immunized into the alveolar submucosa with horseradish peroxidase (HRP) in complete Freund's adjuvant. Ultrastructural demonstration of antigen and specific antibody was performed by incubation of cryosections in an HRP solution, followed by peroxidase cytochemistry. Anti-HRP antibody-containing cells were observed in the draining lymph nodes from 2 to 9 weeks after immunization. The bulk of these cells were located in the medullary cords. The extracellular antibody and antibody-containing cells were also found in germinal centers (GCs) from 3 to 9 wk, and 3 wk, respectively, after immunization. The results suggest that the specific antibody response was most enhanced 3 wk after primary immunization. Therefore, at this time we further challenged rats with the topical application of HRP to the gingival sulcus. The results showed that antigen penetrated through the junctional epithelium into the underlying connective tissue and from here was cleared by macrophages or via the lymphatics. In the draining lymph nodes, antigen first appeared in the subcapsular sinus and eventually became retained within GCs. Between 3 and 5 days, the GCs of challenged rats contained more mature-type anti-HRP antibody-containing cells than those of non-challenged rats. The sequence of events observed suggests that antigen challenge applied topically to the gingival sulcus can induce the active GC reaction in the draining lymph nodes of immunized rats.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 34 (1999), S. 0 
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We examined the levels of anti-thymocyte/T lymphocyte autoantibody (ATA) in the serum of mice injected intraperitoneally with lipopolysaccharides (LPS) from periodontopathic bacteria; Porphyromonas gingivalis, Actinobacillus actinomyceterncomitans, Fusobacterium nucleatum, Capnocytophaga ochracea, and non-oral Escherichia coli. All of the LPS induced IgM-ATA. Among these, LPS from C. ochracea induced the highest level of IgM-ATA, whereas that of P. gingivalis induced the lowest. The peritoneal T lymphocytes of mice injected with LPS were bound by IgM-ATA. Peritoneal B-1 (CD5+B) cells stimulated by each LPS produced much more IgM-ATA than splenic B-2 (CD5− B) cells, suggesting that B-1 cells might be responsible for the production of these antibodies. Serum of mice injected with C. ochracea and F. nucleatum LPS showed cytotoxicity against thymocytes in the presence of rabbit complements. Binding and cytotoxicity were confirmed by IgM purified from serum of the mice injected with C. ochracea LPS. Furthermore, serum of mice treated with C. ochracea, F. nucleatum or A. actinomycetemcomitans LPS inhibited the proliferation of thymocytes. However, purified IgM from the serum of mice treated with C. ochracea LPS failed to produce the same inhibition. Our results suggest that LPS from certain species of periodontopathic bacteria can induce IgM-ATA in the serum and these antibodies may modulate the local immune network in periodontal tissues.
    Type of Medium: Electronic Resource
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