Expression and characterization of a Rana pipiens amelogenin protein

Amelogenin, the major protein of developing enamel matrix, controls enamel crystal growth via unique supermolecular features. While much has been contributed to our understanding of mammalian amelogenin function, little is known about how amelogenin and its unique physico-chemical features have evolved among vertebrates. Here we report, for the first time, amphibian amelogenin recombinant protein expression and characterization in Rana pipiens . In order to characterize R. pipiens amelogenin, the newly discovered amelogenin coding sequence was amplified, subcloned, and expressed in Eshcerichia coli . Our newly generated R. pipiens amelogenin-specific antisera resolved a major 19-kDa band on western blots of frog tooth extracts and revealed an enamel organ tissue-specific localization pattern using immunohistochemistry. Using mass spectroscopy, a single major compound with a molecular weight of 21.6 kDa was detected, which corresponded to the amino acid sequence-based molecular weight prediction of the His fusion recombinant protein. Dynamic light scattering studies resolved 41-nm radius subunits compared with 14-nm radius subunits from mouse recombinant amelogenin controls. Transmission electron microscopy revealed defined spherical subunits in R. pipiens matrix self-assembly in contrast with a homogeneous 'stippled' matrix in mouse amelogenin matrix self-assembly. Our data suggest that R. pipiens amelogenin is distinguished from mammalian amelogenins by a number of unique physico-chemical properties which may be related to specific modes of crystal formation in frog enamel.     

Prevalence of mutans streptococci isolated from complete dentures and their susceptibility to mouthrinses

The aims of this study were to evaluate the incidence of mutans streptococci (MS - sessile form) on complete maxillary dentures after use of a specific denture paste, and to determine the minimum inhibitory concentration (MIC) and maximum inhibitory dilution (MID) of 3 oral mouthrinses: Cepacol, Plax and Periogard. Seventy-seven complete denture wearers were randomly assigned into 2 groups, according to the product used for denture cleaning: Control group - conventional dentifrice (Kolynos-Super White); and Test group: experimental denture cleaning paste. Denture biofilm was collected at baseline and after 90 and 180 days after treatment by brushing the dentures with saline solution. After decimal serial dilution, samples were seeded onto agar sucrose bacitracin to count colonies with morphological characteristics of MS. MS identification was performed by the sugar fermentation tests. After this procedure, brain heart infusion broth (BHI) was added to oral mouthrinses (Plax, Cepacol e Periogard) and seeded on Petri dishes. The colonies were seeded using the Steers multiplier and, after the incubation, the MIC and MID of the mouthrinses were calculated. The results showed an incidence of 74.0% (n=57) of MS in the 77 complete dentures examined in the study, being 76.3% (n=29) of the Control group (conventional dentifrice) and 71.8% (28) of the Test group (experimental denture cleaning paste). In both groups, the number of positive cases for MS decreased from day 0 to day 180. In the Test group there was a slight decrease in the incidence of Streptococcus mutans 90 days after use of the experimental denture cleaning paste, which was not observed in the Control group. As regards to mouthrinses, for both groups, Periogard showed antimicrobial action with the highest dilution, followed by Cepacol and Plax. In conclusion, the incidence of MS in complete dentures was high and Periogard was the mouthrinse with the strongest antimicrobial action against MS. The experimental denture cleaning paste showed a slight action against S. mutans after 90 days of treatment.     

Conversion of one-step to two-step self-etch adhesives for improved efficacy and extended application

PURPOSE: One-step self-etch adhesives have restricted use due to their acid-base incompatibility with autocured composites and their behavior as permeable membranes after polymerization. This study examined the feasibility of their conversion to two-step self-etch adhesives via the adjunctive use of a non-solvented, relatively hydrophobic resin coating. METHODS: iBond, Xeno III and Adper Prompt were used either in multiple coats, or in a single coat followed by the use of a layer of Scotchbond Multi-Purpose Plus bond resin for coupling to light- and auto-cured composites. Four types of experiments were performed. Bonded specimens were examined with TEM after immersion in an ammoniacal silver nitrate tracer. Fluid flow measurements of iBond were conducted using the two application protocols to compare the permeability of the bonded dentin with the original smear layer. Permeability of vital dentin bonded with both application protocols were compared for the transudation of dentin fluid across the bonded dentin. Microtensile bond strengths of dentin bonded with the two protocols were examined for their compatibility with an auto-cured composite. RESULTS: The results of the four experiments were complementary. iBond and Xeno III exhibited "apparent incompatibility" to auto-cured composites that resulted from their inherent permeability. This was confirmed by the presence of dentin fluid transudate on the adhesive surfaces when they were bonded to vital dentin. Conversely, Adper Prompt exhibited "true incompatibility" to auto-cured composites that was caused by adverse acid-base interaction, masking the inherent permeability of this adhesive. "True" and "apparent" incompatibility issues were eliminated upon their conversion to two-step self-etch adhesives.     

Salivary gland tumors in a Brazilian population: a retrospective study of 496 cases

Salivary gland tumors are uncommon and the microscopical features can be complex. Epidemiological data of these tumors in the various parts of the world can be helpful for a better understanding of its biology and clinical characteristics. In this study, 496 epithelial and mesenchymal tumors of major and minor salivary glands diagnosed at Londrina Cancer Institute during the period from 1972 to 2001 were reviewed. Out of all cases, 335 (67.5%) were classified as benign and 161 (32.5%) as malignant. The majority of the cases occurred in the parotid gland (67.7%), followed by the minor salivary glands (22.8%) and submandibular gland (9.5%). Among the minor salivary gland tumors, the palate was the most frequent location (67%). The tumors affected more commonly adult patients with peak incidence between 40 and 50 years of age and with a slightly predominance in females. Pleomorphic adenoma was the most frequent tumor representing 54.2% of all cases, followed by mucoepidermoid carcinoma (13.5%), Warthin's tumor (8.5%) and adenoid cystic carcinoma (7.9%).     

New biomarker evidence of oxidative DNA damage in whole saliva from clinically healthy and periodontally diseased individuals

BACKGROUND: There is an increasing body of evidence implicating reactive oxygen species in the pathogenesis of periodontal tissue destruction. 8-Hydroxy-deoxyguanosine (8-OHdG) is one of the most commonly used markers to evaluate oxidative damage in a number of disorders including chronic inflammatory diseases. The aim of the present study was to evaluate 8-OHdG levels in whole saliva of patients with periodontitis and to assess the changes after initial treatment. METHODS: Saliva samples were collected from 78 patients with untreated periodontitis and 17 healthy control subjects. Clinical parameters and levels of 8-OHdG were assessed first to establish a baseline and again after initial periodontal treatment from 15 patients. 8-OHdG levels were determined by enzyme-linked immunosorbent assay. RESULTS: The mean value of 8-OHdG in the saliva of periodontally diseased subjects, 4.28 +/- 0.10 ng/ml, was significantly higher (P<0.01) than that of clinically healthy subjects (1.56 +/- 0.10 ng/ml). A significant decrease in salivary 8-OHdG was observed after therapy (P<0.01). CONCLUSION: In the present study, we evaluated for the first time 8-OHdG levels in whole saliva of patients with periodontitis and assessed changes after initial periodontal treatment. Our study indicated that 8-OHdG levels in saliva appear to reflect the status of periodontal health.     

Relationship between clinical probing depth and reactivity to the BANA test of samples of subgingival microbiota from patients with periodontitis

The enzymatic test BANA (N-benzoyl-DL-arginine-naphthylamide) was used to analyze the subgingival microbiota of 28 patients aged 26 to 55 years old with a diagnosis of adult periodontitis. Samples were collected with periodontal curettes at 513 sites, with a mean number of sites of 18.3 +/- 8.8 per patient. The results of the BANA test were correlated with the initial measurements of pocket depth. The data showed a statistically significant correlation between increasing probing depth and a positive BANA test. BANA test detected the presence of BANA-positive microorganisms at sites of < 3 mm probing depth in a statistically significant proportion. Negative (BANA 1) and weakly positive (BANA 2) BANA tests were inversely correlated with increasing pocket depth, and positive (BANA 3) BANA tests were directly correlated with increasing pocket depth. On the basis of the presents results, we consider the BANA test to be of practical applicability in periodontal clinical practice and to represent an important auxiliary diagnostic tool for patients with adult periodontitis.     

Clinical application of a new compact computed tomography system for evaluating the outcome of regenerative therapy: a case report

BACKGROUND: The limitations of conventional 2-dimensional (2-D) radiographs have been emphasized in many studies. Because the image is a 2-D map of the 3-dimensional (3-D) tooth and periodontal tissue, these structures may be superimposed on each other. Recently, 3-D image analysis by computed tomography (CT) was introduced to dentistry, but it has been used only rarely in the periodontal field. METHODS: The purpose of this case report was to introduce the clinical application of a newly developed, compact computed tomography system for evaluating the outcome of regenerative therapy in an adult patient with periodontitis (male, aged 55 years). To evaluate the bone defects including furcation involvement, we took an intraoral radiograph and performed CT scanning on tooth #19. We recorded a number of clinical parameters at the time of surgery. We compared the images of the bone defect obtained by CT images and the conventional radiograph with the true bone defect morphology at the surgical site. RESULTS: One year after the periodontal surgery, we again took CT scans and a conventional radiograph, and the new images of the bone defect were compared and evaluated. The new CT images were reconstructed for 3-D evaluation and compared with those taken before surgery. The CT provides 3-D images of excellent quality for evaluating the morphology of the periodontal bone defect and furcation involvement. CONCLUSIONS: We consider that CT is a useful aid in periodontal examination and diagnosis, and in the prediction and evaluation of periodontal treatment outcomes.     

Waist circumference is associated with locomotive syndrome in elderly females

Background

Central obesity has been proved to be a strong risk factor for numerous health-related problems as well as mortality. However, there have been no studies on the relationship between central obesity and locomotive syndrome (LS). The present study investigated the influence of central obesity on LS.

Methods

A total of 217 females between the ages of 60 and 79 years (mean 68.2 ± 5.0 years) who completed the questionnaires, physical examination and physical performance tests in the Yakumo study in 2011–2012 were enrolled in this study. Participants were assessed according to the 25-Question Geriatric Locomotive Function Scale (GLFS-25), visual analog scale (VAS) for lower back pain (LBP) and knee pain, and the Roland Morris Disability Questionnaire (RDQ). LS was defined as having a score of >16 points on the GLFS-25. Height, weight, waist circumference (WC), hip circumference, % body fat and bone mineral density were measured. Body mass index and waist-to-hip ratio were calculated. The timed up-and-go test, one-leg standing time with eyes open, 10-m gait time and maximum stride were assessed. Back muscle strength and grip strength were measured. The relationships between obesity-related parameters and GLFS-25, RDQ, VAS and physical performance tests were analyzed.

Results

The GLFS-25, LBP and knee pain showed significant correlation with most of obesity-related parameters. Among obesity-related parameters, WC was most strongly related to the GLFS-25, LBP and knee pain. When participants were stratified by WC, larger WC was significantly associated with a higher GLFS-25 score, higher prevalence of LS and higher VAS for LBP and knee pain as well as poorer results in some physical performance tests even after adjustment by age.

Conclusions

The present study revealed that central obesity is significantly associated with LS, and WC can be a useful parameter to assess the risk of LS in elderly women.