Global Deletion of Pannexin 3 Resulting in Accelerated Development of Aging-Induced Osteoarthritis in Mice

Objective: Osteoarthritis (OA) results in pathologic changes in the joint tissue. The mechanisms driving disease progression remain largely unclear, and thus disease-modifying treatments are lacking. Pannexin 3 (Panx3) was identified as a potential mediator of cartilage degeneration in OA, and our previous study in mice indicated that deletion of the Panx3 gene delayed surgically induced cartilage degeneration. This study was undertaken to examine the role of Panx3 in other OA subtypes, particularly primary OA during aging, in a mouse model of aging-induced OA. Methods: Wild-type (WT) and Panx3−/− C57BL/6J (Black-6) mice, ages 18–24 months, were analyzed by micro–computed tomography to investigate bone mineral density and body composition. Joints were harvested from the mice, and histopathologic analysis of the joint tissue for OA development was conducted with a specific focus on changes in articular cartilage, subchondral bone, and synovial tissue. Results: Global loss of Panx3 in aging mice was not associated with increased mortality or changes in body composition. Mice lacking Panx3 had shorter appendicular skeletons than WT mice, but overall the body compositions appeared quite similar. Panx3 deletion dramatically accelerated cartilage degeneration and subchondral bone thickening with aging in both 18-month-old and 24-month-old mice, while promoting synovitis in 18-month-old mice. Conclusion: These observations in a mouse model of OA suggest that Panx3 has a protective role against the development of primary aging-associated OA. It appears that Panx3 has opposing context-specific roles in joint health following traumatic injury versus that associated with aging. These data strongly suggest that there are differences in the molecular pathways driving different subtypes of OA, and therefore a detailed understanding of these pathways could directly improve strategies for OA diagnosis, therapy, and research

Influence of endodontic sealer composition and time of fiber post cementation on sealer adhesiveness to bovine root dentin

This study aimed to assess the influence of the type of endodontic sealer (salicylate resinbased sealer vs. two endodontic sealers) and the time of fiber post cementation after root filling on the post adhesion to bovine root dentin. Sixty bovine roots were assigned to six groups (n=10), considering an experimental design with two factors (factorial 3x2): endodontic sealer factor in three levels [epoxy resin-based sealer (AH Plus), eugenol-based sealer (Endofill), and salicylate resin-based sealer plus mineral trioxide aggregate - MTA (MTA Fillapex)] and time for post cementation factor in two levels (immediate post cementation or 15 days after root canal filling). After post cementation, 2-mm-thick slices were produced and submitted to push-out test. The failure modes were analyzed under a 40× stereomicroscope and scored as: adhesive at cement/dentin interface; adhesive at cement/post interface; cement cohesive; post cohesive; dentin cohesive; or mixed. Data were analyzed using two-way ANOVA and Tukey’s post-hoc tests (α=0.05). When the fiber posts were cemented immediately after the root canal filling, the bond strengths were similar, independent of the endodontic sealer type. However, after 15 days, the epoxy resin-based sealer presented higher bond strength than the other sealers (p<0.05). Comparison between each sealer in different experimental times did not reveal any differences. The main failure type was adhesive at dentin/cement interface (89.4%). The time elapsed between the root canal filling and post cementation has no influence on post/root dentin adhesion. On the contrary, the type of endodontic sealer can influence the adhesion between fiber posts and root dentin.Este estudo objetivou avaliar a influência do tipo de cimento endodôntico (um cimento à base de resina de salicilato e dois cimentos endodônticos) e do tempo decorrido entre a obturação do conduto e a cimentação do pino de fibra na adesão de pinos de fibra à dentina radicular bovina. Sessenta dentes bovinos foram divididos em seis grupos (n=10), considerando um desenho experimental de dois fatores (3x2): cimento endodôntico em três níveis [à base de resina epóxica (AH Plus), eugenol (Endofill) e resina de salicilato e MTA (MTA Fillapex)] e o tempo para cimentação em dois níveis (cimentação imediata e 15 dias pós a obturação). Após cimentação do pino de fibra, fatias com 2 mm de espessura foram obtidas e submetidas ao teste de push-out. Os padrões de falha foram analisados em estereomicroscópio (40×) e classificados em: adesiva na interface cimento/dentina, adesiva cimento/pino, coesiva do cimento, coesiva do pino, coesiva da dentina e mista. Os dados foram analisados através dos testes de ANOVA a dois fatores e post hoc de Tukey (a=0,05). Quando os pinos de fibra foram cimentados imediatamente após a obturação dos condutos, a resistência adesiva foi similar, independentemente do tipo de cimento endodôntico. Entretanto, após 15 dias, os dentes obturados com cimento resinoso à base de resina epóxica apresentaram os maiores valores de resistência adesiva (p<0,05). Os valores de resistência adesiva do mesmo cimento nos diferentes tempos experimentais não foram alterados. O principal tipo de falha foi adesiva na interface cimento/ dentina (89,4%). O tempo decorrido entre a obturação dos condutos e a cimentação do pino não influenciou a adesão do pino de fibra à dentina radicular. Por outro lado, o tipo de cimento endodôntico influencia a adesão entre dentina radicular e pinos de fibra

Effect of three radicular dentine treatments and two luting cements on the regional bond strength of quartz fibre posts

The purpose was to investigate by push-out tests and scanning electron microscopy (SEM)/energy-dispersive spectroscopy (EDS) the effect, after first acid etching the post space walls, of three radicular dentine treatments on the regional bond strength of quartz fibre posts placed using two heavily filled resin luting cements. The crowns of 39 extracted maxillary central incisors were sectioned transversely 2 mm coronal to the labial cement-enamel junction and the roots endodontically treated. After standardized post space preparations and etching 15 s with 32% phosphoric acid, 36 roots were randomly divided into six equal groups. Quartz fibre posts (D.T. LIGHT-POST) were placed using three radicular dentine treatments (0.9% sodium chloride (NaCl) for 60 s, 10% sodium hypochlorite (NaOCl) for 60 s, 17% ethylenediaminetetraacetic acid (EDTA) for 60 s followed by 5.25% NaOCl for 60 s) and two resin composite luting cements (ONE-STEP PLUS/DUO-LINK; ONE-STEP PLUS/LuxaCore Dual). Transverse segments (S1-S7), 1.00 mm (SD = 0.05 mm) thick, were sectioned from the coronal 8 mm of each root. Push-out bond strength tests were performed on coronal, middle and apical post space segments (S2, S4, S6) at a crosshead speed of 0.5 mm/min. Data were recorded and analyzed using a two-way mixed ANOVA design (a = 0.05). Three segments (S1, S5, S7) from roots in each group were examined using SEM/EDS. After post space preparation, acid etching and using each of the three radicular dentine treatments, the three remaining roots were sectioned longitudinally for SEM observation of the post space walls. At all root segment sites, the mean bond strengths from using 0.9% NaCl were significantly lower than for the other two radicular dentine treatments (P ≤ 0.02), and DUO-LINK cement had significantly higher mean bond strengths than LuxaCore Dual cement (P ≤ 0.01). There was a significant linear trend for reduced bond strengths from coronal to apical post space segments (P < 0.001), which was supported by the SEM/EDS observations of dentine tubule appearance and resin tag formation. Acid etching followed by either 10% NaOCl or 17% EDTA and 5.25% NaOCl dentine treatments of the post spaces provided good adhesion and resin luting cement tag infiltration of dentinal tubules in the coronal and middle segments in particular.Haiyan Mao, Yaming Chen, Kevin H-K. Yip, Roger J. Smale

Evidence of mother-child transmission of Helicobacter pylori infection Evidência da transmissão mãe-filho da infecção por Helicobacter pylori

BACKGROUND: Low socioeconomical status is a major risk factor for natural acquisition of Helicobacter pylori (H. pylori) infection in developing countries. Its transmission route is unknown but studies suggest person-to-person transmission. AIM: To evaluate seropositivity of anti-H. pylori antibodies in family members of infected symptomatic index patients as compared to family members of symptomatic uninfected index patients. PATIENTS AND METHODS: One hundred and twelve family members of 38 patients who underwent endoscopy to exclude peptic disease were studied. Patients were deemed H. pylori infected or not infected when rapid urease test and histology were both positive or both negative. The family members underwent ELISA serology using the Cobas Core II Kit (Roche) and were classified into three groups: I - 29 family members of 10 H. pylori (+) duodenal ulcer index patients; II - 57 family members of 17 H. pylori (+) index patients without duodenal ulcer; III - 26 family members of 11 H. pylori (-) index patients. RESULTS: Seropositivity of group I and II (infected patients) was higher than the control group, 83% vs 38%, specially in mothers, 81% vs 18%, and in siblings 76% vs 20%. Differences between fathers' seropositivity was not statistically significant in the three groups: 100% vs 86% vs 70%. Seropositivity of all family members (mother, father and siblings) between infected group (I vs II) was similar. CONCLUSION: Prevalence of H. pylori infection was higher in family members of infected patients, but was similar among family members of infected patients with and without duodenal ulcer. H. pylori infection is more frequent in mothers and siblings of infected index children. A common source of infection cannot be excluded, but facts suggest that person-to-person transmission occurs, specially from mother to child.<br>O estrato socioeconômico baixo é o maior fator de risco para a aquisição natural da infecção por Helicobacter pylori em países em desenvolvimento. As vias de transmissão são desconhecidas embora estudos sugerem transmissão pessoa-pessoa. OBJETIVO: Avaliar a soropositividade de anticorpos anti H. pylori em familiares de pacientes sintomáticos infectados comparados a de pacientes não infectados. CASUÍSTICA E MÉTODOS: Foram estudados 112 familiares de 38 pacientes encaminhados para afastar doença péptica. Os pacientes foram submetidos a exame endoscópico, sendo realizadas quatro biopsias gástricas para pesquisa de H. pylori: duas para teste rápido da urease e duas para histologia (HE/Giemsa). Foi considerado infectado por H. pylori quando ambos os exames resultaram positivos. Nos familiares foi realizada sorologia com método ELISA, utilizando-se o Kit Cobas Core II (Roche), sendo considerado resultado positivo a titulação 7U/mL. Os familiares foram divididos em três grupos: grupo I: 29 familiares de 10 pacientes com úlcera duodenal H. pylori+; grupo II: 57 familiares de 17 pacientes sem úlcera duodenal H. pylori+; grupo III: 26 familiares de 11 pacientes H. pylori-. Foi testada a associação entre grupos e positividade através de uma extensão do teste exato de Fisher (método de Montecarlo SPSS), sendo analisada a soropositividade em cada um dos membros da família: pai, mãe, irmãos e o binômio mãe/pai e para a avaliação de múltiplas variáveis utilizou-se ANOVA. RESULTADOS: Os familiares de pacientes H. pylori+ apresentaram maior soropositividade comparado com o grupo controle, 83% vs 38%, sendo maior nas mães 81% vs 18% e irmãos 76% vs 20%. A soropositividade do pai não foi estatiscamente significante, quando comparados os três grupos de pacientes: 100% vs 86% vs 70%. A soropositividade de todos os membros da família, mãe, pai e irmãos nos grupos de úlcera duodenal H. pylori+ e sem úlcera duodenal H. pylori+ foram semelhantes. CONCLUSÃO: Familiares de pacientes infectados apresentam mais infecção por H. pylori. A soropositividade foi semelhante entre os familiares dos pacientes infectados com e sem úlcera duodenal. Infecção por H. pylori é mais freqüente em mães e irmãos de pacientes infectados; ao contrário, nos pais não houve diferença estatisticamente significante nos três grupos. As crianças apresentam mais infecção quando ambos os pais são H. pylori+ e existe uma concordância do resultado da sorologia entre os cônjuges. Não podemos afastar uma fonte comum de infecção, mas os fatos nos sugerem que a transmissão acontece de pessoa a pessoa e especialmente da mãe para filho e entre os irmãos