摘要:

The levels of volatile sulphur compounds (VSC) in periodontal pockets and mouth air have been found to correlate with severity of the disease process. The purpose of this study was to examine the influence of hydrogen sulphide and methyl mercaptan on protein metabolism of human gingival fibroblasts. The incorporation of labelled amino acids into protein was used to evaluate effects on total protein content. Changes in collagenous protein concentration were monitored by release of radioactivity following collagenase digestion as well as direct analysis of hydroxyproline. Both thiols were found to reduce total protein synthesis, with mercaptan exerting a greater adverse effect. In cultures exposed to mercaptan, total protein was reduced by 35%. The changes in total protein were accompanied by a corresponding decrease in collagenase‐digestible protein. Hydroxyproline analysis of CH3SH‐exposed cultures confirmed the changes associated with collagenous proteins. It indicated that in comparison to the controls the CH3SH‐exposed cultures had a 70% reduction in collagen which resulted from a combined effect of suppressed synthesis and increased rate of collagen degradation. The possibility of thiol reaction with collagen was determined using in vitro systems in which type I collagen was reacted with varying concentrations of [35S]‐H2S. The carboxymethyl (CM) cellulose assays of resulting reaction mixtures indicate that [35S]‐radioactivity was incorporated directly into αl, α2, β11, β12 peptide chains. Furthermore, upon exposure of collagen to elevated H2S concentrations, the H2S converted some of the acid‐soluble collagen to a more soluble product which could be extracted in neutral salt and analyzed by CM‐cellulose chromatography. This effect on collagen solubility may make it more susceptible to enzymatic degradation and contribute to the increased destruction of collagen observed in the thiol‐treated

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1992.tb01736.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Tumor necrosis factor‐alpha (TNF‐α) has been shown not only to induce the biosynthesis and secretion of collagenase but also to change the organization of cytoskeletal components. In the present study we explore the correlation between the biosynthesis of collagenase (by mRNA hybridization, indirect immuno‐fluorescence and collagenolytic activity), and cytoskeletal reorganization (by rhodamine‐phalloidin staining of F‐actin) induced in fibroblasts by recombin‐ant TNF (rTNF). In the concentration range of 1–100 ng/ml, rTNF increased extracellular collagenase activity 8‐fold and collagenase mRNA 4‐fold. In addition, whereas the collagenase mRNA was detected as early as 24 h post‐treatment, the appearance of extracellular collagenase activity required 48 h. Using phalloidin to follow the organization of the cytoskeleton we observed that rTNF disrupted the parallel array of stress fibers normally observed in the perinuclear region. In contrast to the time required to affect collagenase synthesis, the effect of rTNF on stress fiber organization occurred as early as 6 h post‐treatment. Finally, while the number of cells exhibiting this change increased with increasing concentrations of rTNF, a maximum of about 30% of the cells showed this effect. Interestingly, double staining studies demonstrated that both stress fiber changes and procollagenase production occurred in the same cells. This finding, together with the observation that the cytoskeletal disorganization preceded collagenase gene induction by at least 18 h is consistent with the conclusion that the organizational status of the microfilaments may have a role as a regulator of procolla

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1992.tb01737.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The presence of adrenergic nerve fibers was demonstrated ultrastructurally in the human periodontal ligament obtained from extracted premolar teeth from 8 young patients. The nerve endings were located close to arterioles. The results suggest that they seem to control blood flow in the human periodontal ligament.

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1992.tb01738.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Comparisons between plaque index (PII) and bacterial counts have been made already; however, these did not take into account the area used for plaque sampling. The objective of the present study was to determine the correlation between the PII score, the number of bacteria and the bacterial plaque vitality when dental plaque was repeatedly sampled from the same area in each subject during early plaque accumulation. Between intervals of optimal oral hygiene, 10 participants refrained from all oral hygiene measures for periods of 1, 2, 3, 4 and 5 days. The PII was recorded on the vestibular surface of all first premolars as local PII:LS. For statistical reasons, the scores of the independent variable LS were added for each subject giving LS* values ranging from 0 to 8. The plaque sampled from this specific surface was circumscribed by the marginal gingiva and an acrylic splint, giving reproducible areas for plaque collection. Total microscopic bacterial counts (BC), colony forming units of anaerobes (CFUan) and aerobes (CFUae), and proportions of vital bacteria (VF) were compared with LS* values. BC and LS* values were strongly correlated. CFUanand CFUaeincreased significantly with LS*, but this increase was higher for LS* 0 to 4 than for LS* 4 to 8. The ratio between vital and dead microorganisms, assessed by two different methods, was low when an LS* of 0 was recorded, with higher ratios registered for LS* values 4 and 8.

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1992.tb01739.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Determinations of interocclusal tactile threshold levels so far have involved neither appropriate psychophysical approaches nor an assessment of the mechanical and thermal properties of the foils used. Twenty subjects (12 females) aged 18 to 50 (mean age 35) were tested for their absolute threshold level (RL). Both the method of limits and the staircase method were applied to determine the active or passive RL. For the active RL assessment, foils of different thicknesses were placed between edge‐to‐edge opposed incisors during gentle biting. Inner ear receptors of the blindfolded subjects were blocked by broad band noise applied through earphones, because vibrations induced by occlusal contact and conducted through bone might be perceived by these receptors. The foils presented were aluminum (Al), tin (Sn), polyester (PE) and calibrated steel (St) (thickness ranging from 8 to 50 μm) which offer different physical and thermal properties. The range of RL of the group varied between 8 μm for aluminum to 46 μm for polyester for 50% correct assessments. Increasing the foil temperature from room temperature (20°C) to body temperature (35°C) significantly increased the RL for conducting materials (one‐way blocked ANOVA). These results indicate that temperature exchange takes place while presenting conducting foils at 20°C (cold stimulus) interocclusally, which influences the RL by activating thermosensitive receptors. The passive RL determination with classical von Frey‐hairs resulted in a mean axial RL of 3.0 g. Both psychophysical RL assessments (method of limits, staircase method) gave reproducible and similar results as ascertained by ANOVA. Furthermore, a positive correlation was established between active and passive RL (Pearson correlation test). It is concluded that the physical and thermal properties of the foils need careful consideration in future experiments on threshold determination. Although active RL determination may involve the activation of non‐periodontal receptors, it remains a realistic parameter to monitor tactile fu

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1992.tb01740.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The changes in cytokeratin expression by the developing oral mucosa of 10 to 23‐week‐old human fetuses were studied by indirect immunofluorescence using a panel of 15 monoclonal antibodies. The lining and masticatory mucosae were incompletely differentiated in 10‐wk fetuses, since they expressed identical patterns of cytokeratins (CK 4, 5, 8, 13, 18, 19 and probably CK 14, 16, 17) very similar to that of adult alveolar mucosa. The main difference was the presence of cytokeratins 8, 18 and 19 in embryonic tissues. Cytokeratins 1, 2, 10 and 11 began to appear in gingival and hard palate epithelium from wk 11, predicting the differentiation of the masticatory mucosa by wk 16. The patterns of cytokeratin expression in the 23‐wk fetus in the lining and masticatory mucosae appear to be different. In lining mucosa, the only difference from the 10th wk is a decrease in cytokeratins 8, 18 and 19, whereas the pattern of cytokeratin expression in masticatory mucosa (CK 1, 2, 4, 5, 8, 10. 11, 13, 18, 19 and probably CK 14, 16 and 17) is now very near that of adult gingiva. This pattern appears, as in the adult, to be similar to that of the epidermis in the same

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1992.tb01741.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1992.tb01742.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The clinical diagnostic features of gingivitis such as redness, swelling and bleeding are based on vascular changes. It would be desirable to directly make use of the vascular changes in the clinical evaluation of gingival inflammation. In the present study, capillary microscopy was used for quantitative evaluation of the vascular reaction of the marginal gingiva in response to experimental plaque formation in 6 healthy students. Low power stereomicroscopy was used and the number of vessel endings was evaluated from stereophotographs. A gradual increase in the number of visible vessel endings was observed over time of plaque accumulation. The mean ± SEM at baseline was 24.0 ± 6.30 as compared to 77.0 ± 10.02 at day 28. After removal of plaque and re‐institution of oral hygiene measures, a return toward pre‐experimental numbers was observed. Throughout the test the number of vessel endings within the proximal‐papillary part of the marginal gingiva was less than that within the basal‐labial part. The results indicate that low power stereophotomicroscopy is a useful tool for the clinical study of inflammatory changes in the gingival v

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1992.tb01743.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Anaerobic Gram‐negative bacteria dominate in periodontitis locations, while Gram‐positive bacteria characterize healthy sites. A well‐established Gram‐positive flora might therefore inhibit the colonization of Gram‐negative pathogens. The purpose of the present investigation was to examine whether endogenousS. sanguiscould prevent, or reduce, periodontal bone loss in rats infected with a virulentP. gingivalisstrain. Sixty specific pathogen‐free Wistar rats were divided into 6 groups. Doxycycline was administered in the drinking water for 2 weeks to the groups A, B, C, and D to suppress the preexisting microflora in the mouth. Rats in groups A and C were subsequently inoculated with an 5.sanguisstrain, isolated from one of the rats, once a day for 5 d. Infection withP. gingivalis381 was then carried out for 5 d in groups A, B, and E. Group F was not treated with doxycycline nor infected with bacteria and served as untreated control. Six weeks after theP. gingivalisinoculation, the rats were killed. Periodontal bone levels were assessed radiographically and morphometrically, and serum antibody against P. gingivalis 381 was determined by a fluorescence immunoassay. Periodontal bone support, determined radiographically, was reduced in group B (doxycycline‐treated,P. gingivalis‐inoculated) compared with the other groups. In contrast, the morphometric determination showed no differences between the groups. In group B antibody levels against two differentP. gingivalis381 cell surface antigens were significantly elevated. The data indicated that the preinoculation of an endogenousS. sanguisstrain protected against a reduction of the radiographically assessed periodontal bone support induced byP. gingivalis381. and similarly prevented an elevation of the total serum antibody response toP

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1992.tb01744.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The mechanism of aggregation ofEikenella corrodens1073 withE. corrodensaggregating factor (EcAF) which was purified from submandibular‐sublingual (SM‐SL) saliva was investigated. Heating (100°C, 10 minutes) or protease treatment ofE. corrodenscells abolished the aggregating activity. The aggregation was inhibited by adding N‐acetyl‐D‐galactosamìne (GalNAc) and saccharides which contain a galactose residue at the non‐reducing end. The aggregating activity was sensitive to EDTA and was restored by Ca2+but not by Mn2+or Mg2+. Neuraminidase treatment of EcAF increased their ability to aggregate.E. corrodens, suggesting that the sialic acids on EcAF interfere with aggregation. These data suggest that the aggregation ofE. corrodens1073 with EcAF is mediated by specific interactions between a bacterial cell surface lectin‐like substance and a complementary GalNAc‐like receptor. EcAF also aggregated 16 strains of oral bacteria including periodontopathic bacteria such asPorphyromonas(Bacteroides) gingivalis 381 andActinobacillus actinomycetemcomitansATCC29522; however, those aggregations were not inhibited by GalNAc. Therefore, EcAF appears to have more than two types of bacterial binding site and plays important roles in accumulation of dental plaque by forming a complex network of plaque bacteria including periodo

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1992.tb01745.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY