Ameloblastoma RNA profiling uncovers a distinct non-coding RNA signature.

Ameloblastoma of the jaws remains the top difficult to treat odontogenic tumour and has a high recurrence rate. New evidence suggests that non-coding RNAs (ncRNAs) play a critical role in tumourgenesis and prognosis of cancer. However, ameloblastoma ncRNA expression data is lacking. Here we present the first report of ameloblastoma ncRNA signatures. A total of 95 ameloblastoma cases and a global array transcriptome technology covering > 285.000 full-length transcripts were used in this two-step analysis. The analysis first identified in a test cohort 31 upregulated ameloblastoma-associated ncRNAs accompanied by signalling pathways of cancer, spliceosome, mRNA surveillance and Wnt. Further validation in an independent cohort points out the long non-coding (lncRNAs) and small nucleolar RNA (snoRNAs): LINC340, SNORD116-25, SNORA11, SNORA21, SNORA47 and SNORA65 as a distinct ncRNA signature of ameloblastoma. Importantly, the presence of these ncRNAs was independent of BRAF-V600E and SMO-L412F mutations, histology type or tumour location, but was positively correlated with the tumour size. Taken together, this study shows a systematic investigation of ncRNA expression of ameloblastoma, and illuminates new diagnostic and therapeutic targets for this invasive odontogenic tumour.

Tissue reactions to subperiosteal onlays of demineralized xenogenous dentin blocks in rats.

OBJECTIVES: This study was undertaken to examine the influence of partial demineralization of xenogenous dentin on bone formation in an osteoconductive environment. MATERIALS AND METHODS: Sixty dentin blocks, 2-3 mm thick and 4 mm in diameter, were prepared from developing teeth of young pigs. Forty blocks were demineralized in 24% ethylenediaminetetraacetic acid (pH 7.0) for 1, 2, 6 or 12 h. Forty adult rats divided into eight groups with five rats in each group were used. A sagittal midcranial incision was made from the occipital to the frontal region. Through a subperiostal dissection, a pocket was created on each side of the skull. One demineralized block was placed on one side, and a non-demineralized block was placed on the contralateral side, or the pocket was left empty as controls. Thus, eight experimental groups with five rats in each were formed. RESULTS: Resorption increased significantly with increasing degree of demineralization while bone formation increased significantly with increasing degree of demineralization, provided inflammation was compensated for. This suggests an important role for inflammation or infection control during the healing period of osteogenic implants to optimize osseous integration in an osteoconductive environment. CONCLUSION: Partial demineralization of xenogenous dentin blocks may provide a method for optimizing the integration of dentin onlays in an osteoconductive environment, thus stabilizing the implant and slowing down replacement resorption.

Validation of an algorithm for chronic periodontitis risk assessment and prognostication: analysis of an inflammatory reactivity test and selected risk predictors.

BACKGROUND: Patients with severe forms of chronic periodontitis present with varying degrees of decreased inflammatory reactivity. A previously reported algorithm for chronic periodontitis risk assessment and prognostication is based on the analysis of some 20 risk predictors. One of these predictors is a skin provocation test that assesses the individual patient's reactivity to a lipid A challenge. The aim of this report was to analyze results from validation data for the algorithm with respect to the contribution of results of the skin provocation test as a risk predictor for the progression of chronic periodontitis and to compare these results with the contribution from other predictors, namely smoking, angular bony destruction, furcation involvement, abutment teeth, and endodontic pathology. METHODS: Data from a previously reported clinical validation sample were used for the analysis, including the calculation of quality measures and explanatory values using different types of regression analysis and non-parametric testing. RESULTS: Smoking, endodontic pathology, abutment teeth, angular bony destruction, and furcation involvement presented with individual explanatory values for periodontitis progression between 4% and 13% and highly significant parameter estimates. Explanatory values for the results of the skin provocation test ranged between 2.6% and 5.1% depending on the disease severity group, with a positive predictive value of 82% for the identification of high-risk patients. CONCLUSION: The skin provocation test provided a clinically significant contribution to the quality of analysis with the periodontitis risk and prognostication algorithm, in particular in the selection of high-risk patients for in-depth individual tooth analysis.

Validation of an algorithm for chronic periodontitis risk assessment and prognostication: risk predictors, explanatory values, measures of quality, and clinical use.

BACKGROUND: The American Academy of Periodontology has recently stated that, "[risk assessment will become] increasingly important in periodontal treatment planning and should be part of every comprehensive dental and periodontal evaluation." (J Periodontol 2006;77:1608). Unaided risk assessment and prognostication show significant variability because chronic periodontitis is a multifactorial disease. This report summarizes the clinical validation of an algorithm for chronic periodontitis risk assessment and prognostication. The algorithm is a Web-based analytic tool that integrates some 20 risk predictors and calculates scores indicating levels of risk for chronic periodontitis for the dentition (Level I) and, if an elevated risk is found, prognosticates disease progression tooth by tooth (Level II). METHODS: An independent clinical validation sample was generated in an open, prospective clinical trial and analyzed in a predetermined validation plan. RESULTS: The analyses identified two threshold scores above which significant progression of periodontitis was found. Based on these scores, sufficiently high explanatory values with significant and increasing parameter estimates for increasing risk were established in Level I, justifying detailed analysis tooth by tooth in Level II. Subsequent prognostication of chronic periodontitis in Level II was found to be accompanied by clinically relevant measures of quality in relation to rates of disease progression. Three score intervals representing increasing levels of periodontitis progression were identified corresponding to increasing levels of significant annual marginal bone loss. CONCLUSIONS: The predictors included in the algorithm reflect a relevant selection for periodontitis risk assessment. Risk assessment and prognostication with the algorithm provides the clinician with a validated, reliable, consistent, and objective tool supporting treatment planning.

Assessment of dysplastic dentin in osteogenesis imperfecta and dentinogenesis imperfecta.

Two semiquantitative scoring systems, Clinical Radiographic Score (CRS) and Dysplastic Dentin Score (DDS), were introduced for analyzing degree of dysplastic manifestations in dentin. The utility of both systems was demonstrated in a large material of teeth from patients with dentinogenesis imperfecta (DI) and osteogenesis imperfecta (OI). Twenty teeth from healthy controls, 81 teeth from 40 patients with OI, and 18 teeth with DI without OI (DI type II) were examined. The degree of dysplasia was correlated with type and form of OI and type of DI. The median DDS did not differ between DI associated with OI (DI type I) and DI type II. DDS in OI patients without clinical signs of DI was above that of control teeth. Both circumpulpal and mantle dentin showed increased DDS, although circumpulpal dentin was more severely affected. The median DDS was highest for the most severe type of non-lethal OI (type III). DDS increased significantly with form (severity) of OI. A significant association between DDS and CRS was found, although diagnosis of DI in less severe cases was not possible based on radiographic or clinical signs alone. Thus, the DDS system proved valuable when the CRS system based on radiographic/clinical manifestations failed, the most significant finding being subclinical histological manifestations of DI in patients with OI but without clinical or radiographic signs of DI. These subtle dysplastic changes are most likely an expression of genetic disturbances associated with OI and should not be diagnosed as DI, but rather be termed histologic manifestations of dysplastic dentin associated with OI.

Expression and localization of alpha- and beta-carbonic anhydrase in Helicobacter pylori.

Helicobacter pylori, the causative agent of peptic ulcer disease, expresses two different forms of the zinc-containing enzyme carbonic anhydrase (CA) (alpha and beta), catalyzing the reversible hydration of CO(2). Presumably, the high CO(2) requirement of H. pylori implies an important role for this enzyme in the bacterial physiology. In this paper, expression of the CAs has been analyzed in three different strains of the bacterium, 26695, J99 and 17.1, and appears to be independent of CO(2) concentration in the investigated range (0.1-10%). Presence of the potent and highly specific CA inhibitor, acetazolamide, in the medium does not seem to inhibit bacterial growth at the given sulfonamide concentration. Moreover, the localization and distribution of the alpha-CA was analyzed by immunonegative staining, while SDS-digested freeze-fracture immunogold labelling was used for the beta-form of the enzyme. The latter method has the advantage of allowing assessment of protein localization to distinct cell compartments and membrane structures. The resulting electron microscopy images indicate a localization of the beta-CA in the cytosol, on the cytosolic side of the inner membrane and on the outer membrane facing the periplasmic space. The alpha-enzyme was found attached to the surface of the bacterium.