摘要:

Periodontal diseases are characterized in part by generation of oxygen free radicals, which can cause breaks in cellular DNA strands. Repair of damaged DNA is dependent upon the synthesis of poly(ADP‐ribose)(PADPR) catalyzed by PADPR synthetase, an enzyme known to be activated by the broken ends of DNA strands. We measured the activities of PADPR synthetase and of PADPR glycohydrolase. which degrades PADPRS, in gingival biopsy specimens from 16 sites with adult periodontitis and 12 clinically healthy control sites. The results indicated that sites with periodontitis displayed markedly reduced PADPR synthetase activity compared with healthy control sites, whereas PADPR glycohydrolase activity was not changed. The mean specific activity of PADPR synthetase for the diseased specimens was one‐sixth of that of the healthy specimens (p<0.001). The PADPR synthetase activity was negatively correlated with the Gingival Index (rs=‐0.60), pocket depth (rs=‐0.70) and bleeding upon probing (rs=‐0.72). Cultured fibroblasts derived from clinically characterized healthy and diseased gingival sites reflected similar patterns of enzyme activity. The mean specific activity of PADPR synthetase for the diseased‐site cultures (n=9) was 56±7% (p<0.001) of the cultures from healthy control sites (n=6). These results suggest that a reduced level of PADPR synthetase activity is associated with increased inflammation and periodontal destruction, and that the ability to synthesize PADPR is compromised in adult p

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1996.tb01408.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Morphologic and chemical characterization of root surfaces treated with either the CO2, laser, Nd:YAG, or Nd:YAG with water/air surface cooling (Nd:YAG‐C) was completed using scanning electron microscopy (SEM) and FTIR photoacoustic spectroscopy (FTIR/PAS). Specimens for morphologic analysis consisted of 20 extracted single rooted teeth unaffected by periodontal disease. The specimens were exposed at varying energy densities to a single pass of the laser. SEM examination revealed, for all lasers, a direct correlation between increasing energy densities and depth of tissue ablation and width of tissue damage. The Nd:YAG‐C required higher energy densities than either the CO2or Nd:YAG lasers to achieve the same relative depth of tissue ablation. Regardless of energy density, and in contrast with other laser types, areas treated with the Nd:YAG‐C did not exhibit collateral zones of heat damage. Specimens for spectroscopic examination consisted of 12 disks, 6x2 mm, cut from debrided root surfaces of extracted, unerupted human molars. The spectral results indicate a substantial reduction in the absorption bands attributable to protein and an additional band at 2015 cm‐1in specimens exposed to the Nd:YAG without water. In the presence of water/air coolant, the band at 2015 cm‐1appears only at a substanially higher energy density. The spectra of the CO2treated specimens, with the char layer present, show a significant reduction in the protein bands and additional bands at 2015 and 2200 cm‐1, that are tentatively assigned to the cyanamide and cyanate ions, respectively. These results suggest a reaction of the organic matrix and mineral with las

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1996.tb01409.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

The aim of this study was to investigate the influence of the structure of corals on their resorption kinetics after implantation in subcutaneous areas. Three types of coral (Porites astreoides, Montastrea annularis and Dichocenia stokesi) identical in composition but different in structure were implanted, for periods of 1 and 2 months in subcutaneous sites in OF l mice. The resorption of the implants was studied by means of qualitative (histology, scanning electron microscopy, fluorochrome labelling method) and quantitative approaches (gravimetric method). The results of the qualitative study revealed a process of irregular deterioration of the coral, linked to the detachment of crystals at the surface of the implant. The results of the quantitative study showed that the speed of resorption increases with the implantation time and the open porosity of the coral. These reactions are explained by the increase of the surface exchange area in contact with factors responsible for resorption: biological medium and cells. When considering the choice of coral as a bone substitute, these factors must be taken into account to allow thein situmaintenance of the implant over a sufficiently long period of time according to the clinical situation.

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1996.tb01410.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Cementogenesis of the molars with aging was studied using senescence accelerated mouse (SAM) which included SAMP2/Iw and SAMP8//Iw as prone strains, and SAMRl/Iw as a resistant strain. Morphometric analysis was done for the cementum thickness at 2, 6, 12 and 16 months of age on 4 parts of the mice, i.e. at the mesial (M), the distal (D), the apical (A) and the furcational (F) cementum of the maxillary first molar. SAMRl/Iw was also studied at 20 months of age. Mean cementum thickness was statistically analyzed for age and strain differences. Mean thicknesses of the M and the D cementum in SAMP2/Iw and in SAMP8//Iw were usually higher than those in SAMRl/Iw. Furthermore, there were significant differences between SAMP2/Iw and SAMRl/Iw, and between SAMP8//Iw and SAMRl/Iw, both at 12 and 16 months of age. There was no difference in mean thickness in the F cementum in either strain and at any age. In the A cementum, SAMP2/Iw displayed significantly thicker cementum than SAMRl/Iw at 6, 12 and 16 months of age. The degree of molar eruption was thought to be more accelerated in SAMP2/Iw than in SAMRl/Iw. However, the thickness of the A cementum was not different for SAMP8//Iw and SAMRl/Iw in any age group. In this study, 2 conclusions were drawn as follows: first, that SAMP2/Iw and SAMP8//Iw exhibited more accelerated cementogenesis than SAMRl/Iw in the M and the D cementum. Secondly, several factors such as intrinsic factors, occlusal forces and degree of attrition affected the cementogenesis of the M and the D, the F and the A cementum, respectively.

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1996.tb01411.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

The aim of the present study was to analyze the cytotoxicity of some bacterial species associated with periodontal diseases. The specificity of cytotoxicity was estimated against cells of various origin and from different individuals. The reference bacteria wereActinobacillus actinomycetemcoinitans, Porphyromonas gingivalisandFusobacterium nucleatum. These bacteria were cultured for 24 h in liquid media and the supernatants were used in cytotoxicity assays. The target cells used were human gingival fibroblasts (GF). dermal fibroblasts (K4), gingival epithelial cells (E) and HeLa‐cells (HeLa). These cells were exposed at 4 h or 24 h, respectively, to various concentrations of culture supernatants from the selected bacteria. The influence on the viability and metabolism of the cells were estimated quantitatively as increase in neutral red uptake and lactic acid production. Growth medium supernatants ofP. gingivalis33277 were strongly cytotoxic to gingival fibroblasts after 24 h incubation, compared to supernatants ofP. gingivalis381 or W 50, A. actinomycetemcoinitans or F. nucleatum cultures. The toxic effect ofP. gingivalis33277 decreased drastically after heat inactivation, which indicates effects of proteins. By adding anti‐sera the cytotoxicity ofP. gingivalis 33277could be dose dependently neutralized, which was not the case when supernatants of A.actinomycetemcoinitanswas tested. Target cells of epithelial origin did not show increased cytotoxicity toP. gingivalis 33277. The results of the present study strengthen the hypothesis thatP. gingivalisremains as a suspect causative key component in periodontal disea

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1996.tb01412.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Numerous data strongly suggest the involvement of cytokines and the matrix metalloproteinase collagenase (MMP‐1) in the pathogenesis of periodontitis. Recently, we have demonstrated that, upon culturing under the influence of IL‐ lα+EGF, a large amount of inactive procollagenase (MMP‐1) is stored in the extracellular matrix of periosteal tissue. We now show that this endogenous reservoir of proenzyme can be operative after activation with plasmin and is able to induce a rapid and almost complete breakdown of the collagenous extracellular matrix. The level of collagen degradation following activation showed a strong correlation with the amount of proenzyme that was incorporated in the tissue. The highest levei of degradation (70% of the total amount of collagenous proteins) was found with the IL‐lα+EGF‐treated explants, followed by those treated with IL‐1α alone (35%). Explants cultured with EGF or in the absence of cytokines, containing only small amounts of procollagenase, showed little collagen breakdown following plasmin activation (7%). Inhibition of metalloproteinases by EDTA, or blockage of plasmin by PMSF, prevented the degradation in all explants irrespective of the amount of proenzyme present in the tissue. Our findings demonstrate that endogenous proenzyme stored in a native connective tissue matrix can be activated at a later time interval which results in a massive breakdown of the tissue. This study shows a possible pathway of collagenase‐induced breakdown without recent de novo synthesis of the enzyme. Such a sequence may be operative in chronic inflammatory diseases, such as periodontitis, where production of procollagenase under the influence of cytokines spans a longer time period, whereas breakdown is often characterized by a

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1996.tb01413.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Cytokines play an important role in the pathology associated with chronic inflammatory diseases. We measured the total amounts [picograms (pg)] and concentrations (pg/μl) of interleukin‐1 alpha (IL‐lα), interleukin‐8 (IL‐8) and interferonalpha (IFN‐α) in 20 s gingival crevicular fluid (GCF) samples obtained from 2 diseased and 2 healthy sites in 20 subjects with periodontitis, and from 2 healthy sites in 20 subjects without disease. Both the mean amount and concentration of IL‐lα were significantly higher (p<0.001) in diseased sites compared to healthy sites in subjects with disease. The results for IL‐8 and IFN‐α differed depending on the method of reporting. Whereas the amount of IL‐8 was significantly higher (p<0.01) in diseased sites, the mean concentration of IL‐8 was lower compared to healthy sites. The mean amount of IFN‐α was similar in health and disease; however, the concentration of IFN‐alpha was significantly lower in diseased sites (p<0.001) corresponding to the significant increase in crevicular fluid volume (p<0.001). There were no significant differences in the amount or concentrations of the 3 cytokines between healthy sites from subjects with disease and healthy sites from healthy controls. The total amounts of both IFN‐α and IL‐8 were correlated between healthy and diseased sites in subjects. These data suggest that, while the disease status of a site is the major determinant of the levels of these cytokines locally, subjects with high levels of IL‐8 and IFN‐α in healthy sites also tend to have high levels of these cytokines in diseased sites. Finally, both the concentrations and total amounts of IL‐8 and IFN‐α were significantly correlated in diseased sites, suggesting that levels of these two cytokines rise or fall in tandem. The combination of decreased IL‐8 and decreased IFN‐α concentrations at diseased sites may reflect the reduced

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1996.tb01414.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

In this study, the major periodontal pathogensActinobacillus actinomycetemcomitansandPorphyromonas gingivaliswere detected in subgingival plaque samples from patients with periodontal disease by polymerase chain reaction (PCR) and conventional culture methods. 170 plaque samples from 43 patients were analysed;A. actinomycetemcomitansandP. gingivaliswere each detected in 40 (24%) of samples by PCR. whereas conventional culture methods detectedA. actinomycetemcomitansandP. gingivalisin 25 (15%) and 18 (11%) of samples, respectively. The proportion of patients carrying A. actinomycetemcomitans in at least 1 sampled periodontal site was 17/43 (40%) by PCR and 13/43 (30%) by culture; forP. gingivalisthis was 2/43 (28%) by PCR and 9/43 (21%) by culture. Only 5 samples, from 3 patients, harboured bothA. actinomycetemcomitansandP. gingivalis. It is concluded that PCR is more accurate than conventional culture methods for identification of these periodontal pathogens in subgingival plaque samples and has a higher frequency of detection.

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1996.tb01415.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

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 nucleatumandCapnocytophaga ochracea. F. nucleatumandC. ochraceaLPS induced higher levels of serum IgM‐ and IgG‐RF, whileP. gingivalisLPS showed the least induction. In addition, wet weights of spleen and serum IgM and IgG concentration were markedly increased inF. nucleatumLPS 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 t

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1996.tb01416.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

We hypothesized that one mechanism underlying advanced periodontal disease in diabetes may involve oxidant stress in the gingiva, induced by the effects of Advanced Glycation Endproducts (AGEs), the irreversible products of non‐enzymatic glycation and oxidation of proteins and lipids which accumulate in diabetic plasma and tissue. Infusion of AGE albumin, a prototypic ligand, into mice resulted in increased generation of thiobarbituric acid reactive substances (TBARS) compared with infusion of non‐glycated albumin in the gingiva, as well as in the lung, kidney and brain. Pretreatment of the animals with the antioxidants probucol or N‐acetylcysteine (NAC) prevented the generation of TBARS in the gingiva. Affinity‐purified antibody to AGEs demonstrated increased immunoreactivity for AGEs in the vasculature and connective tissues of the gingiva in streptozotocin‐induced diabetic mice compared to non‐diabetic controls. Increased immunoreactivity for AGEs was also demonstrated in the gingiva of diabetic humans compared with non‐diabetic individuals via immuno‐histochemistry and ELISA. Consistent with these data, immunohistochemistry for heme oxygenase‐1, a marker of enhanced oxidant stress, was increased in the gingival vasculature of diabetic mice and humans compared with non‐diabetic controls. These data suggest that AGEs present in diabetic gingiva may be associated with a state of enhanced oxidant stress, a potential mechanism for accele

ISSN:0022-3484    

DOI:10.1111/j.1600-0765.1996.tb01417.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY