Microbiological Aspects of Naturally Occurring Primary Endodontic Infections in Dogs.

Dental fractures are common in dogs, but data on microbiology of naturally occurring primary endodontic infections, and their relation to clinical and radiographic signs, are lacking. Samples were obtained from root canals of 32 periodontally healthy fractured teeth under aseptic conditions and immediately cultured for aerobic and anaerobic bacteria. Cultures were further identified by matrix-assisted laser desorption/ionization, time of flight technology. Sixty-one bacteria (30 bacterial species) were isolated from root canals; 54% were Gram-negative bacteria, 53% were facultative anaerobic, and 42% were anaerobic bacteria. Number of bacterial species in the root canals declined with the duration of fractures over 12 months. No statistically significant association was found between the number of bacterial species involved in the root canal infection and any of the clinical or radiographic signs of endodontic disease. Naturally occurring primary endodontic infections in dogs appear to be polymicrobial and involve only a selected number of opportunistic pathogen species.

Oral health and systemic inflammatory, cardiac and nitroxid biomarkers in hemodialysis patients

Background: Periodontal diseases have systemic inflammatory effects and have been adversely associated with cardiovascular diseases, which are also the most frequent cause of death in the end-stage renal disease. The aim of this cross-sectional study was to investigate the oral health and serum biomarkers among the hemodialysis (HD) patients in Slovenia. Material and Methods: 111 HD patients were periodontally examined and their sera were assayed for C-reactive protein (CRP), cardiac troponin T (TnT), nitrite/nitrate (NOx) and antibody levels to A. actinomycetemcomitans and P. gingivalis. The association of oral health with systemic response was analyzed with Kruskal-Wallis test, Fisher’s exact test and multivariate linear regression. Results: Bleeding on probing without periodontal pockets was present in 5.2%, calculus without periodontal pockets in 42.1%, shallow periodontal pockets in 39.5% and deep periodontal pockets in 13.2% of dentate patients. There were 28.8% edentulous participants. 63.1% of the patients had CRP levels higher than 3 mg/L and 34.2% higher than 10 mg/L. TnT was detectable in all participants, with 25.2% exhibiting levels higher than 100 ng/L. The median level of NOx was 43.1 µmol/L. Participants with higher CRP were more likely to be edentulous and have higher TnT levels. A direct association of oral health with TnT or NOx was not detected. Conclusions: HD patients in Slovenia have compromised oral health and increased serum inflammatory and cardiac biomarkers. Edentulousness was an independent predictor for the increased CRP, indicating a need for improved dental care to retain the teeth as long as possible (AU)

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Aerosolized clindamycin is superior to aerosolized dexamethasone or clindamycin-dexamethasone combination in the treatment of severe Porphyromonas gingivalis aspiration pneumonia in an experimental murine model.

Adjunctive corticosteroid treatment to reduce excessive local inflammatory response in pneumonia is controversial. To study the effects of an early local adjunct dexamethasone treatment on the course of pneumonia and inflammatory/cytokine response, mice were intratracheally inoculated with live Porphyromonas gingivalis and treated with either clindamycin (C), dexamethasone (D), C+D combination, or were not treated (Pg). Six mice from each group were euthanized at 6, 24, 72, and 168 hours after inoculation. Levels of tumor necrosis factor (TNF)-α, soluble TNF-α receptors (sTNFR1 and sTNFR2), interleukin (IL)-1ß, and IL-6 in the serum and lung-homogenate supernatant were determined. Lung samples were histopathologically assessed and all findings compared to those found in 24 sham-inoculated mice (phosphate-buffered saline [PBS]). Severe P. gingivalis-induced bronchopneumonia progressed from 24 hours, peaked at 72 hours, and resolved after 168 hours with changes in local and systemic cytokine levels. Clindamycin-treated mice developed only mild bronchopneumonia that resolved fast (72 hours) with an early (6-24 hours) normalization of local and systemic cytokine levels. Similar course of pneumonia and cytokine level changes were observed in mice treated with C+D, but later. Early (6-24 hours) local elevation of sTNFRs was observed in C and C+D groups of mice, whereas nontreated (Pg) mice had increased systemic sTNFRs. Severe bronchopneumonia with delayed resolution was observed in D-group mice, with an early local and systemic decrease in sTNFR1 and persistent elevation of local TNF-α. Clindamycin or a clindamycin-dexamethasone combination treatment significantly improves the course of P. gingivalis-aspiration pneumonia, but more so if clindamycin alone is used. A favorable course of pneumonia seems to be associated with an early elevation of sTNFRs and normalization of TNF-α.

Early systemic inflammatory response in mice after a single oral gavage with live Escherichia coli is evidenced by increased TNF-alpha and nitric oxide production.

Twenty-four female BALB/c mice were orally inoculated with 10(8) CFU Escherichia coli ATCC 25922 and euthanized 2.5, 7, 13 and 25 h post-inoculation. The levels of organ nitric oxide (NO) and plasma endotoxin, TNF-alpha and nitrite/nitrate (NO(x)) were compared to those found in sham-inoculated mice, to evaluate systemic host-response to a low-level oral exposure to Gram-negative bacteria. Organ bacterial culture and immunohistochemistry for iNOS were performed on lungs, liver, kidneys and brain from all mice. Organ NO and plasma TNF-alpha levels were higher in E. coli-inoculated animals, but no differences were detected in plasma endotoxin levels, NO(x) or iNOS immunostaining for any of the animal groups. Single oral gavage with live E. coli stimulates an early systemic immune response in clinically healthy mice as evidenced by increased plasma TNF-alpha and organ NO levels, but bacteremia and endotoxemia are not related to this inflammatory response.

Systemic use of selective iNOS inhibitor 1400W or non-selective NOS inhibitor l-NAME differently affects systemic nitric oxide formation after oral Porphyromonas gingivalis inoculation in mice.

OBJECTIVE: Nitric oxide synthase (NOS) inhibitors are reported to protect against the local tissue damage in gingivitis and periodontal disease by reducing nitroxidative stress during inflammation, but their systemic effects are not well investigated. DESIGN: NOS inhibitors systemic effects were investigated in a murine chronic oral inoculation model using live Porphyromonas gingivalis ATCC 33277 (0.3 ml; 10(9)cfu/ml) or sterile broth (0.3 ml). Organ nitric oxide (NO) and plasma nitrite/nitrate (NOx) were determined in mice treated with non-selective NOS inhibitor l-NAME (50mg/kg/24h i.p.) or selective iNOS inhibitor 1400W (10mg/kg/6h i.p.) for the last 5 days of the experiment. Differences between groups were evaluated by nonparametric Wilcoxon's rank-sum one-sided two-sample test and the results compared to those obtained from sham-treated (sterile broth) sham-inoculated animals (water for injection i.p./6h). RESULTS: Repeated ingestion of P. gingivalis resulted in generalized production of NO in organs and NOx in plasma, the levels of both typically being reduced in P. gingivalis-inoculated-1400W-treated mice, whilst the use of l-NAME was largerly ineffective, even promoting NO/NOx formation. Application of either inhibitor to sham-inoculated animals enhanced NO/NOx formation, due only in part to the repeated i.p. injections. CONCLUSIONS: The systemic use of 1400W or l-NAME differently affects systemic nitric oxide formation in mice orally challenged with P. gingivalis, but the sequelae of such an intervention should be evaluated further.

Lack of soluble tumor necrosis factor alpha receptor 1 and 2 and interleukin-1beta compartmentalization in lungs of mice after a single intratracheal inoculation with live Porphyromonas gingivalis.

Porphyromonas gingivalis aspiration pneumonia induces local and systemic cytokine responses, but the dynamic of the immune response following lung exposure to live P. gingivalis is poorly understood. Groups of 50 12-week-old male BALB/c mice were inoculated intratracheally with live P. gingivalis ATCC 33277 using low dose (2 x 10(5) colony-forming units [CFU]), high dose (2.9 x 10(9) CFU), or phosphate-buffered saline (PBS; sham-inoculated), and the 3 groups were sacrificed at 2, 6, 24, 72, 168 hours. Lung and serum samples were collected for tumor necrosis factor alpha (TNF-alpha), soluble TNF-alpha receptors (sTNFRs), interleukin (IL)-1beta, and IL-6 analysis and lung histology. Pneumonia, only observed in the high-dose group, was associated with an early increase in lung TNF-alpha, IL-1beta, and IL-6, whereas no significant changes were observed in lung sTNFRs. Serum sTNFRs were significantly increased in high-dose animals at all times. IL-1beta elevation occurred earlier in serum than in lungs. IL-1beta was also significantly elevated in serum from low-dose animals at 6 hours. Serum IL-6 and sTNFRs remained raised at 7 days, whereas all other measured cytokines returned to basal levels with resolution of pneumonia. Development of pneumonia is dependent on the P. gingivalis dose; however, part of the cytokine response is unique to the systemic compartment, even in animals that do not develop pneumonia.

Single oral inoculation with Escherichia coli (ATCC 25922) stimulates generalised production of nitric oxide in mice.

Nitric oxide (NO) production was investigated in the lungs, thoracic aorta, heart, liver, spleen, kidneys and brain of mice inoculated orally with Escherichia coli ATCC 25922. Detection of NO was performed by electron paramagnetic resonance (EPR) using diethyldithiocarbamate (DETC) spin trap. Nitric oxide synthase (NOS) inhibitors [nonselective: L-NAME and inducible NOS (iNOS) selective: 1400W] were used to determine the source of NO. Spin-trap only and untreated mice were included as controls. Within 2.5 hours (h) of a single oral inoculation with E. coli half of the animals had increased NO levels in all investigated organs. Thereafter the signals dropped before increasing again to reach maximal median values by 25 h in all organs of all inoculated mice. The most intense response occurred in livers, followed by aorta and lungs. Early (2.5 h) inhibition of the signal was achieved using both NOS inhibitors. L-NAME was also effective at 25 h, while 1400W-treated mice had increased NO levels beyond 7 h. The generalised increase in NO production in the short and longer term indicates a host response to E. coli administered by the oral route of infection.

Periodontal disease burden and pathological changes in organs of dogs.

Bacterial plaque associated periodontal disease is the most common chronic infection in man and dogs. In man, there is an association between periodontal disease and myocardial infarction and stroke, while in dogs it has also been associated with changes in internal organs. Inflamed periodontal tissues present a 'periodontal disease burden' to the host and the extent of this inflammatory disease burden is likely to affect the degree of associated pathological change in distant organs. This hypothesis was investigated in dogs with naturally occurring periodontal disease. Post-mortem investigations including periodontal assessment, standard necropsy, and organ histology were performed on 44 mature toy and miniature Poodles (related, periodontitis predisposed breeds) that died naturally or were euthanized based on clinical disease. Animals with gross primary organ pathology were excluded. The periodontal disease burden was estimated from the total surface area of periodontal pocket epithelium using six measurements of probing depth for each tooth and the tooth circumferences. Ordinal logistic regression (OR) analysis established that for each square centimeter of periodontal disease burden there was a 1.4-times higher likelihood of greater changes being present in the left atrio-ventricular valves (OR = 1.43), plus 1.2 and 1.4 times higher likelihoodfor greater liver and kidney pathology (OR = 1.21; OR = 1.42), respectively The results show that there is a link between the estimated 'periodontal disease burden' resulting from plaque-bacteria associated periodontal disease and the level of internal pathology in this population, implying that periodontitis might contribute to the development of systemic pathology in dogs.

Histological evaluation of the pulp in teeth from dogs with naturally occurring periodontal disease.

The purpose of this investigation was to evaluate the pulp of dog teeth affected by advanced periodontal disease. Histological examination was done on demineralized teeth extracted during clinical treatment of mature, client owned small and medium-size breed dogs with either good periodontal health or with advanced naturally occurring periodontal disease. Routinely stained sections from 5 clinically normal teeth and 22 teeth with advanced periodontitis from dogs between 5 and 12-years of age were examined using light microscopy. The pulp cavities of most teeth were narrow with low cellularity and some fibrosis of the pulp. Findings specific to periodontally affected teeth included acute and chronic pulpitis, vascular congestion, and pulp necrosis. A glomus body was identified in the pulp of one tooth and areas of poorly mineralized cementum were seen in both normal and diseased teeth. Age related changes in dog teeth appear similar to those reported for man and the rat. In addition to age related changes, the pulp of dog teeth with advanced periodontal disease were frequently inflamed or necrotic. This may reflect the advanced periodontitis affecting these teeth or a mechanical effect related to excessive tooth mobility. Further study is required to determine the etiology and significance of these findings and to investigate pulp status in less severely diseased teeth.

Membrane switch hypothesis. 2. Domain structure of phagocytes in horses with recurrent airway obstruction.

The mechanism of recurrent airway obstruction (RAO) in horses was investigated by measuring the membrane domain structure and oxy-redoxy activity in phagocytes isolated from bronchoalveolar lavage fluid (BAL) and from the blood of healthy and RAO horses by electron paramagnetic resonance (EPR). Differences in the activity of intracellular antioxidant enzymes CAT, GPx, and SOD measured in phagocytes of RAO horses in comparison to healthy horses showed that the phagocytes were affected by oxidative stress. In comparison with polymorphonuclear leukocytes (phagocytes) from the blood of healthy horses the reduction mechanisms in BAL were faster and coincided with the merging of disordered membrane domains, while in horses with RAO the reduction and membrane domain structure remained unchanged. We assume that the merging of lipid domains observed in phagocytes from BAL of healthy horses could promote cluster formation of membrane proteins or ligands, which could trigger the activation process in phagocytes of healthy horses and consequently the physiological response that probably did not happen in phagocytes of RAO horses.

Measurement of total antioxidant capacity in gingival crevicular fluid and serum in dogs with periodontal disease.

OBJECTIVE: To determine whether gingival crevicular fluid (GCF) and serum total antioxidant capacities (TACs) correlate with the degree of severity of periodontal disease in dogs. ANIMALS: 41 Toy and Miniature Poodles. PROCEDURES: After assessment of the degree of severity of naturally occurring periodontitis, GCF samples from both maxillary fourth premolars and a blood sample were collected from each dog. The condition of the periodontium of the entire dentition and at each site of GCF collection was recorded. Clinical parameters assessed included plaque index, gingival index, and probing depth. Radiographic analysis of alveolar bone level was also performed. Total antioxidant capacity was measured in GCF and serum samples by use of a commercial kit. RESULTS: Dogs with gingivitis and minimal periodontitis had significantly higher TAC in GCF than dogs with advanced periodontitis. Bivariate regression analysis revealed significant negative correlations between TAC in GCF and clinical parameters and age. The TAC in serum was significantly negatively correlated with the degree of gingival inflammation but was not significantly correlated with age. CONCLUSIONS AND CLINICAL RELEVANCE: TAC in GCF is related to the degree of severity of periodontal disease in dogs. This is likely the result of release of reactive oxygen species by activated phagocytes and fibroblasts in the inflamed periodontal tissues. The results of our study suggest that the local delivery of antioxidants may be a useful adjunctive treatment for periodontitis in dogs.

In vivo study of different ointments for drug delivery into oral mucosa by EPR oximetry.

The aim of the present study was to determine the rate of transport and long-term effect of a drug applied to the oral mucosa in different ointments. Three ointments with bioadhesive properties: Orabase, Carbopol 935P, and polymethyl methacrylate (PMM) and the ointment Miglyol without such properties were used. Benzyl nicotinate (BN) was used as an active ingredient that causes hyperemia. The kinetics of drug action was measured by electron paramagnetic resonance (EPR) oximetry in vivo using the paramagnetic probe (Lithium phthalocyanine) implanted beneath the epithelium of the buccal mucosa in rats. EPR spectra line-width was proportional to local changes of partial pressure of oxygen (pO(2)) in tissue and was monitored for 90 min after the application of ointments mixed with BN. The greatest increase in pO(2) and the highest efficiency of drug action was observed after the application of 2% BN in PMM (P<0.01). Additionally in PMM the drug effect increased linearly with BN concentration up to 3%, at higher concentrations (3.5 and 4% BN) no further effect was observed. The results demonstrated that the greatest and the longest effect caused by a hyperemic drug in PMM. By increasing the concentration of the drug in PMM higher pO(2) in the oral mucosa can be established but only until the saturation is reached.