Análise histomorfométrica de implantes de titânio puro com superfície porosa versus superfície rugosa

The purpose of this study was to analyze the bone repair around commercially pure titanium implants with rough and porous surface, fabricated using powder metallurgy technique, after their insertion in tibiae of rabbits. Seven male rabbits were used. Each animal received 3 porous-surface implants in the left tibia and 3 rough-surface implants in the right tibia. The rabbits were sacrificed 4 weeks after surgery and fragments of the tibiae containing the implants were submitted to histological and histomorphometric analyses to evaluate new bone formation at the implant-bone interface. Means (%) of bone neoformation obtained in the histomorphometric analysis were compared by Student's t-test for paired samples at 5% significance level.. The results of the histological analysis showed that osseointegration occurred for both types of implants with similar quality of bone tissue. The histomorphometric analysis revealed means of new bone formation at implant-bone interface of 79.69 ± 1.00% and 65.05 ± 1.23% for the porous- and rough-surface implants, respectively. Statistically significant difference was observed between the two types of implants with respect to the amount new bone formation (pO propósito deste estudo foi avaliar a reparação óssea ao redor de implantes de superfície porosa comparados com implantes de superfície rugosa, ambos confeccionados de titânio puro grau 2 por meio da técnica de metalurgia do pó. Os implantes foram inseridos em tíbias de coelhos. Foram utilizados neste estudo 7 coelhos machos, sendo que cada um recebeu 3 implantes de superfície porosa na tíbia esquerda e 3 implantes de superfície rugosa na tíbia direita. Os animais foram sacrificados 4 semanas após a cirurgia e os fragmentos das tíbias contendo os implantes foram submetidos à análise histológica e histomorfométrica, visando analisar a neoformação óssea na interface osso-implante. As médias (%) obtidas na análise histomorfométrica foram avaliadas por meio do teste estatístico t-student de amostras pareadas com nível de significância de 5%. Os resultados da análise histológica mostraram que a osseointegração foi obtida nos dois tipos de implantes com similar qualidade de tecido ósseo. Na análise histomorfométrica, verificaram-se médias de neoformação óssea na interface osso-implante de 79,69% ± 1,00 e 65,05 ± 1,23 para os implantes de superfície porosa e rugosa, respectivamente, e foi observada diferença estatisticamente significante entre os dois tipos de implantes com relação à quantidade de neoformação óssea. Concluiu-se que os implantes de superfície porosa contribuíram para a osseointegração devido à sua maior superfície de contato na interface osso-implante

KIAA1549: BRAF gene fusion and FGFR1 hotspot mutations are prognostic factors in pilocytic astrocytomas

Up to 20% of patients with pilocytic astrocytoma (PA) experience a poor outcome. BRAF alterations and Fibroblast growth factor receptor 1 (FGFR1) point mutations are key molecular alterations in Pas, but their clinical implications are not established. We aimed to determine the frequency and prognostic role of these alterations in a cohort of 69 patients with PAs. We assessed KIAA1549:BRAF fusion by fluorescence in situ hybridization and BRAF (exon 15) mutations by capillary sequencing. In addition, FGFR1 expression was analyzed using immunohistochemistry, and this was compared with gene amplification and hotspot mutations (exons 12 and 14) assessed by fluorescence in situ hybridization and capillary sequencing. KIAA1549:BRAF fusion was identified in almost 60% of cases. Two tumors harbored mutated BRAF. Despite high FGFR1 expression overall, no cases had FGFR1 amplifications. Three cases harbored a FGFR1 p.K656E point mutation. No correlation was observed between BRAF and FGFR1 alterations. The cases were predominantly pediatric (87%), and no statistical differences were observed in molecular alterations-related patient ages. In summary, we confirmed the high frequency of KIAA1549:BRAF fusion in PAs and its association with a better outcome. Oncogenic mutations of FGFR1, although rare, occurred in a subset of patients with worse outcome. These molecular alterations may constitute alternative targets for novel clinical approaches, when radical surgical resection is unachievable.This study was partially supported by CNPq/Universal (475358/2011-2), and FAPESP (2012/19590-0) grants to RMR and to the NIH- P30CA046934 (CCSG Molecular Pathology/Cytogenetics) to MVG and DL

Resistência à corrosão das ligas de 'TI-'MO' em meios contendo íons cloreto e fluoreto, visando à aplicação biomédica

O Ti e suas ligas são os materiais mais utilizados como biomateriais nas áreas biomédicas. Sua biocompatibilidade é resultado da estabilidade do filme de TiO2 formado sobre a superfície do material, protegendo-o contra o processo contínuo de corrosão, agravado por íons agressivos. Neste trabalho, foram utilizadas ligas de Ti fundidas contendo 6, 10 e 15% (m/m) de Mo, Ti cp e Mo metálico. As concentrações de Mo eram específicas às diferentes fases do titânio (para 6%, a fase  era a mais estável; em 10%, a fase  + ; e em 15%, a fase ). Todos os corpos-de-prova foram polidos, e, por meio de técnicas eletroquímicas (potencial de circuito aberto E com o tempo t; voltametria cíclica; espectroscopia de impedância eletroquímica), o comportamento eletroquímico deles foi analisado em soluções simulando o fluido biológico, uma vez que é comum na sociedade moderna o uso de dentifrícios contendo 1450 ppm de flúor e o uso de águas fluoretadas contendo entre 0,6 e 0,8 ppm de flúor para prevenção de cáries. Para a caracterização morfológica e análise do filme formado sobre a superfície do Ti, foram utilizadas, respectivamente, as técnicas de microscopia eletrônica de varredura e espectroscopia de fotoelétrons excitados por raios X. A liga de Ti-15Mo apresentou maior resistência à corrosão, com valores de potenciais menos negativos, seguida das ligas de Ti-10Mo e Ti-6Mo. A maior estabilidade do filme foi observada em solução de Na2SO4 0,15 mol L-1, seguida das soluções de Ringer 0,15 mol L-1, Ringer 0,15 mol L-1 mais NaF 0,15 mol L-1 e NaF 0,036 mol L-1 (voltamogramas). A resistência do filme Rp aumentou com o tempo de imersão para todas as ligas, porém, a resistência da solução Rs aumentou na presença de Cl- e F-, principalmente em F- (diagramas de Bode e Nyquist), o que diminuiu a resistência das...Ti and its alloys are the materials most used as biomaterials in the biomedical fields. Its biocompatibility is due to the stability of TiO2 film formed on this material surface, protecting it against the continuous corrosion process, injured by aggressive ions. In this work were used merged Ti alloys containing 6, 10 and 15% (w / w) of Mo, Ti cp and Mo metal. The Mo concentrations was specific for different phases of titanium (for 6%, the phase  is more stable; for 10%, it is the phase  + ; and for 15%, it is the phase ). All the specimens were polished, and by electrochemical techniques (open circuit potential E with time t; cyclic voltammetry; electrochemical impedance spectroscopy), the electrochemical behavior of them was analyzed in solutions simulating the biological fluid, as it is common in modern society the use of dentifrices containing 1450 ppm of fluoride and the use of fluoridated water containing between 0.6 and 0.8 ppm of fluoride for caries prevention. For the morphological characterization and analysis of the film formed on the Ti surface were used, respectively, techniques of scanning electron microscopy and X-ray photoelectron spectroscopy. The Ti-15Mo alloy showed a higher corrosion resistance, with less negative potential values (variation of E vs. t), followed by the Ti-10Mo and Ti-6Mo alloy. The higher film stability was observed in 0.15 mol L-1 Na2SO4 solution, followed by solutions of 0.15 mol L-1 Ringer, 0.15 mol L-1 Ringer plus 0.036 mol L -1 NaF and 0.036 mol L-1 NaF (voltammograms). The film resistance Rp increased with the immersion time for all alloys, however, the solution resistance Rs increased in the presence of Cl- and F-, mainly F- ions (Bode plots and Nyquist), reducing the alloys resistance against corrosion. There was no pitting corrosion of alloys (microscopy). The film formed on their... (Complete abstract click electronic access below)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Facile Ionic Liquid-Assisted Strategy for Direct Precipitation of Eu2+ -Activated Nanophosphors under Ambient Conditions

International audienceThis work describes a novel ionic liquid (IL)‐assisted synthesis strategy for a direct and easy production of Eu2+‐doped nanoparticles (NPs), where ILs are also used as fluoride sources to avoid the use of elemental fluorine or toxic hydrofluoric acid. Up to now, the direct synthesis of Eu2+‐doped nanophosphors consisted of an enormous challenge, due to the oxidation to Eu3+ observed in hydrous solution, which is commonly used for the preparation of NPs, generating lattice defects and undesired particle growth or agglomeration by additional reducing steps at high temperatures. In contrast, ILs, unless containing ClO4 – or NO3 – anions, do not present an oxidizing character, allowing the direct precipitation of NPs, e.g., using Eu2+ containing starting materials. Here, the undoped and Eu2+‐doped BaFCl NPs have been prepared under atmospheric conditions for the first time using ILs as solvents and also as fluoride source, applying sonochemical and microwave‐assisted approaches. In general, this method bears an enormous potential for an easy synthesis of fluoride materials compared to inconvenient solid‐state methods. In addition, the IL plays the role of a strongly attached protecting shell which represents ≈7–8% of the total NPs weight

Análise histomorfométrica de implantes de titânio puro com superfície porosa versus superfície rugosa

The purpose of this study was to analyze the bone repair around commercially pure titanium implants with rough and porous surface, fabricated using powder metallurgy technique, after their insertion in tibiae of rabbits. Seven male rabbits were used. Each animal received 3 porous-surface implants in the left tibia and 3 rough-surface implants in the right tibia. The rabbits were sacrificed 4 weeks after surgery and fragments of the tibiae containing the implants were submitted to histological and histomorphometric analyses to evaluate new bone formation at the implant-bone interface. Means (%) of bone neoformation obtained in the histomorphometric analysis were compared by Student's t-test for paired samples at 5% significance level.. The results of the histological analysis showed that osseointegration occurred for both types of implants with similar quality of bone tissue. The histomorphometric analysis revealed means of new bone formation at implant-bone interface of 79.69 ± 1.00% and 65.05 ± 1.23% for the porous- and rough-surface implants, respectively. Statistically significant difference was observed between the two types of implants with respect to the amount new bone formation (pO propósito deste estudo foi avaliar a reparação óssea ao redor de implantes de superfície porosa comparados com implantes de superfície rugosa, ambos confeccionados de titânio puro grau 2 por meio da técnica de metalurgia do pó. Os implantes foram inseridos em tíbias de coelhos. Foram utilizados neste estudo 7 coelhos machos, sendo que cada um recebeu 3 implantes de superfície porosa na tíbia esquerda e 3 implantes de superfície rugosa na tíbia direita. Os animais foram sacrificados 4 semanas após a cirurgia e os fragmentos das tíbias contendo os implantes foram submetidos à análise histológica e histomorfométrica, visando analisar a neoformação óssea na interface osso-implante. As médias (%) obtidas na análise histomorfométrica foram avaliadas por meio do teste estatístico t-student de amostras pareadas com nível de significância de 5%. Os resultados da análise histológica mostraram que a osseointegração foi obtida nos dois tipos de implantes com similar qualidade de tecido ósseo. Na análise histomorfométrica, verificaram-se médias de neoformação óssea na interface osso-implante de 79,69% ± 1,00 e 65,05 ± 1,23 para os implantes de superfície porosa e rugosa, respectivamente, e foi observada diferença estatisticamente significante entre os dois tipos de implantes com relação à quantidade de neoformação óssea. Concluiu-se que os implantes de superfície porosa contribuíram para a osseointegração devido à sua maior superfície de contato na interface osso-implante