Are myoepithelial cells responsible for the widespread expression of inducible nitric oxide synthase in pleomorphic adenoma? An immunohistochemical study

Many of the actions of nitric oxide (NO) are still poorly understood. Recently, it has been shown that the inducible isoform of the enzyme nitric oxide synthase, iNOS, is expressed in both salivary ducts and pleomorphic adenoma. The current immunohistochemistry study determined whether or not this distribution correlated with smooth muscle actin (SMA) expression, thereby suggesting the expression by myoepithelial cells in both sites. Twenty cases of histologically confirmed pleomorphic adenoma, the sections of which contained adjacent normal salivary gland tissue, were stained for iNOS and smooth muscle actin (clone 1A4). The salivary ducts of all cases were stained intensely by both antibodies, with smooth muscle actin staining also being noted around acini in the normal gland parenchyma. Moderate or heavy staining for iNOS was found in all specimens of pleomorphic adenoma, with smooth muscle actin being distributed in a similar manner in 19 cases. Smooth muscle actin, but not iNOS, was also noted in blood vessels of both normal glands and tumours. The correlation between iNOS and SMA in pleomorphic adenoma was significant (P<0.001). The presence of iNOS in normal salivary ducts and pleomorphic adenoma is most likely due to expression by myoepithelial cells.     

Increased nuclear ?-catenin expression in oral potentially malignant lesions: A marker of epithelial dysplasia

Background

Deregulation of ?-catenin is associated with malignant transformation; however, its relationship with potentially malignant and malignant oral processes is not fully understood. The aim of this study was to determine and compare the nuclear ?-catenin expression in oral dysplasia and oral squamous cell carcinoma (OSCC).

Material and Methods

Cross sectional study. Immunodetection of ?-catenin was performed on 72 samples, with the following distribution: 21 mild dysplasia, 12 moderate dysplasia, severe dysplasia 3, 36 OSCC including 19 well differentiated, 15 moderately differentiated and 2 poorly differentiated. Through microscopic observation the number of positive cells per 1000 epithelial cells was counted. For the statistical analysis, the Kruskal Wallis test was used.

Results

Nuclear expression of ?-catenin was observed in all samples with severe and moderate dysplasia, with a median of 267.5, in comparison to mild dysplasia whose median was 103.75. Only 10 samples (27.7%) with OSCC showed nuclear expression, with statistically significant differences between groups (p < 0.05).

Conclusions

Our results are consistent with most of the reports which show increased presence of ?-catenin in severe and moderate dysplasia compared to mild dysplasia; however the expression of nuclear ?-catenin decreased after starting the invasive neoplastic process. This suggests a role for this protein in the progression of dysplasia and early malignant transformation to OSCC. Immunodetection of ?-catenin could be a possible immune marker in the detection of oral dysplasia. Key words:Oral squamous cell carcinoma (OSCC), ?-catenin, oral dysplasia.     

Does a clinical evaluation of oral cleanliness correlate with caries incidence in preschool children? Findings from a cohort study

The aim of this study was to assess whether a clinical evaluation of oral cleanliness reflects subsequent caries incidence. Oral examination of 180 children (1- to 4-year-olds) was carried out twice in a six-month period. Caries prevalence at baseline (dfs) in 1- to 2-year-olds (group A) and 3- to 4-year-olds (group B) correlated significantly with oral cleanliness as well as salivary mutans streptococci count (MS). Caries increment (delta(dfs)) correlated significantly with oral cleanliness in group A but not in group B, while delta(dfs) significantly correlated with MS in group B and slightly correlated with that in group A. ANCOVA revealed that dfs was significantly higher at the second examination than at baseline in group B, even after adjusting for oral cleanliness. This finding was confirmed by Wilcoxon test when group B was divided in three categories (low, middle and high) based on oral cleanliness. This suggests that the relationship between delta(dfs) and oral cleanliness decreased with age and that the significant positive correlation found in group B by our point-prevalence survey is derived from the remainder of the positive correlation that occurred at a younger age.     

Is bruxism severity a predictor of oral splint efficacy in patients with myofascial face pain?

Both the efficacy and mechanism of any effect of oral splint therapy for patients with temporomandibular disorders (TMDs) are a matter of controversy. To address these issues, this study tested the hypothesis that oral splints produce the most marked pain relief for those TMD patients with myofascial face pain (MFP) who also brux (i.e. grind or clench) more than other MFP patients. In a 6-week randomized controlled clinical trial, 52 women with MFP were randomly assigned to receive either a full-coverage hard acrylic splint or a palatal-only splint. Bruxism was assessed both by self-report and by an objective assessment of molar microwear changes over a 2-week period prior to the start of the trial. Tested across multiple outcome measures, results indicated that those receiving the full-coverage splint had marginally better improvement on some pain-related measures than those receiving the palatal splint, but severity of bruxism did not moderate the therapeutic effect of the full-coverage splint. These findings strongly argue against the belief that oral splints reduce MFP by reducing bruxism and raise questions about the importance of bruxism in the maintenance of MFP.     

Is negative affectivity associated with oral quality of life?

OBJECTIVES: The personality trait of negative affectivity (NA) is associated with reports of worse physical health, more symptoms and worse health-related quality of life but its associations with oral quality of life (OQOL) are unexplored. In this study we examined the association of NA with OQOL. METHODS: We drew on data from two samples of older men: The VA Dental Longitudinal Study (DLS; n=177) and the Veterans Health Study (VHS; n=514), which included three measures of oral quality of life: the Oral Health-Related Quality of Life Measure (OHQOL), the Oral Health Impact Profile (OHIP), and the Geriatric Oral Health Assessment Instrument (GOHAI). For each OQOL measure, and the GOHAI and OHIP subscales, two regression models were estimated to examine the marginal change in variance due to NA: the first model included age, number of teeth, and self-rated oral health, and the second added NA. RESULTS: In both bivariate and multivariate analyses, higher NA was consistently associated with worse scores on the OQOL measures. In the regression analyses, NA explained an additional.01 to 18% of the variance in OQOL, explaining the most variance in the OHIP and the least in the OHQOL. The addition of NA explained more variance in the more subjective, psychologically oriented GOHAI and OHIP subscales than it did in the more objective, physical function oriented subscales. CONCLUSIONS: Psychosocial factors such as personality are significantly associated with quality of life ratings. Such associations should be taken into account when OQOL measurements are used and interpreted.     

Does the geriatric nutrition risk index predict the prognosis of patients with oral squamous cell carcinoma?

Malnutrition is associated with the prognosis of malignant disease. The geriatric nutritional risk index (GNRI), based on serum albumin (ALB) levels and the present and ideal body weight, is a simple screening tool with which to predict the risk of malnutrition and mortality in patients. We hypothesised that nutritional markers could predict the prognosis of patients with oral squamous cell carcinoma (OSCC). The primary predictor variable was the GNRI score and the primary outcome variable was overall survival (OS). Univariate and multivariate analyses were performed using a Cox proportional hazard model to identify independent prognostic factors. The sample comprised 155 patients, of whom 17 presented with a low GNRI score (≤98) and 138 with a high GNRI score (≥ 98). There was a significant difference in OS when patients were stratified according to GNRI scores, with OS rates of 29.2% and 76.4% for scores of 98 and under and scores of over 98, respectively (p < 0.001). Univariate analyses showed that OS was significantly associated with GNRI score, age, T classification, N classification, stage, body mass index (BMI), prognostic nutrition index, and ALB levels. Analysis identified three independent predictive factors for OS: age (hazard ratio (HR) 2.184; 95% confidence interval (CI) 1.119 to 4.261; p = 0.022), stage (HR 2.684; 95% CI 1.457 to 5.367; p = 0.011), and GNRI score (HR 4.559; 95% CI 2.172 to 9.570; p <0.001). The results suggest that the GNRI score (>98 vs ≤98) is a good prognostic marker in patients with OSCC, along with age and stage.     

Does oral dryness influence pressure pain sensitivity in the oral mucosa of removable denture wearers?

Clinical Oral Investigations - This study aimed to determine if oral dryness is associated with oral pain sensitivity in removable denture wearers. The pressure pain threshold (PPT) in the mucosa...     

Impact of epidermal growth factor receptor,mesenchymal–epithelial transition factor,and insulin-like growth factor receptor 1 expression on survival of patients with oral and oropharyngeal cancer

The aim of this study was to evaluate the impact of expression of epidermal growth factor receptor (EGFR), mesenchymal–epithelial transition factor (c-Met), and insulin-like growth factor receptor 1 (IGF-1R) protein on response to treatment and survival in patients with oral and oropharyngeal squamous cell carcinoma (SCC). EGFR, c-Met, and IGF-1R immunohistochemical (IHC) scores were generated based on the incidence and intensity of expression of the biomarkers evaluated in paraffin-embedded sections of biopsy specimens taken before treatment from 113 patients given neoadjuvant chemoradiotherapy followed by resection for primary locally advanced oral and oropharyngeal SCC. Correlations were assessed between the IHC of the biomarkers and the patients’ clinicopathological variables using Spearman's rank test. Cox's regression models were used to evaluate the impact of EGFR, c-Met, and IGF-1R, expression on survival.     

Is podoplanin expression associated with the proliferative activity of ameloblastomas?

Oral Diseases (2012) 18 , 673–679 Objectives: The aim of this study was to investigate the relationship between podoplanin expression and proliferative activity of ameloblastomas and remnants of the odontogenic epithelium from dental follicles (DF) of unerupted teeth. Subjects and methods: Thirty‐three paraffin‐embedded ameloblastomas and thirty‐two DF obtained of unerupted teeth were analyzed by immunohistochemistry using anti‐human podoplanin and anti‐Ki‐67 antibodies. Podoplanin expression in odontogenic epithelial cells was evaluated using a scoring method, and the Ki‐67 labeling index was determined by the percentage of positive odontogenic cells. Results: All ameloblastomas displayed podoplanin expression in ameloblast‐like cells of the epithelial islands. Membranous expression of podoplanin in ameloblastomas was stronger than in the remnants of odontogenic epithelium (P = 0.001). Statistically significant difference was observed between the cytoplasmic and membranous expression of podoplanin in the remnants of odontogenic epithelium (P = 0.001). The index of epithelial odontogenic proliferative activity, verified by Ki‐67 expression, was higher in ameloblastomas vs remnants of odontogenic epithelium (P < 0.001). No statistically significant correlation was identified between podoplanin and the cellular odontogenic proliferative activity in ameloblastomas and DF (P > 0.05). Conclusions: These results provide evidence that there is no connection between podoplanin immunostaining and odontogenic cellular proliferative activity and suggest a role for membranous podoplanin expression in the local invasion of ameloblastomas.     

Does invasion of oral squamous cell carcinoma occur into a non-pathological fracture of the mandible?

Although the route of invasion of oral squamous cell carcinoma into the intact mandible is well-documented we know of no reports about whether malignant cells invade through non-pathological fractures. A 68-year-old patient presented with a traumatic fracture of the mandible at the site of an existing carcinoma. He had asegmental resection but histological examination showed no evidence of invasion into the bone.