Uso de ligas metálicas básicas em próteses sobre implantes: análise da adaptação marginal

The original protocol for implant prosthesis recommends the use of a gold framework for acrylic and ceramic prosthesis. However, due to its high cost, the use of alternative alloys is desired. This study compares the marginal accuracy of pre-made cylinders versus plastic cylinders cast with two different base metal casting alloys. Five samples each of (1) plastic cylinder cast in cobalt-chromium alloy, (2) plastic cylinder cast in nickel-chromium alloy, and (3) silver-palladium pre-made cylinder (control) were examined for marginal accuracy according to: (A) vertical gap; (B) horizontal gap and (C) horizontal gap depth at the abutment/cylinder interface. Data were submitted to statistical analysis (ANOVA and Student-Newman Keuls, pO protocolo para prótese sobre implantes recomenda o uso de uma infra-estrutura em ouro para próteses metalo-plásticas e metalo-cerâmicas. No entanto, devido ao seu alto custo, o uso de ligas alternativas é desejado. OBJETIVO: Este estudo compara a adaptação marginal de cilindros protéticos pré-fabricados e cilindros protéticos plásticos fundidos com dois tipos de ligas metálicas básicas. MATERIAL E MÉTODOS: 05 amostras de (1) cilindros plásticos fundidos em liga de cobalto cromo; (2) cilindros plásticos fundidos em liga de níquel cromo e (3) cilindros pré-fabricados com cinta metálica em paládio, foram examinados na interface intermediário/cilindro protético na análise de desajuste marginal, considerando-se (A) desajuste vertical, (B) desajuste horizontal e (C) profundidade de fenda. RESULTADOS: os valores médios para o desajuste vertical, horizontal e profundidade foram, respectivamente, 4,13µm, 14,5µm e 6,93µm para o cilindro pré-fabricado em paládio, 23,18µm, 33,2µm e 88µm para os cilindros plásticos fundidos em Níquel cromo e 25,6µm, 51,8µm e 114,54 µm para os cilindros fundidos em cobalto-cromo. CONCLUSÃO: não foram encontradas diferenças estatísticas entre os grupos fundidos (grupo 1 e 2), mas uma adaptação marginal significantemente superior foi observada com os cilindros pré-fabricados quando comparado aos cilindros plásticos fundidos com níquel-cromo e cobalto-cromo para todas as análises

Toward a test of angular momentum coherence in a twin-atom interferometer

We present a scheme well-suited to investigate quantitatively the angular momentum coherence of molecular fragments. Assuming that the dissociated molecule has a null total angular momentum, we investigate the propagation of the corresponding atomic fragments in the apparatus. We show that the envisioned interferometer enables one to distinguish unambiguously a spin-coherent from a spin-incoherent dissociation, as well as to estimate the purity of the angular momentum density matrix associated with the fragments. This setup, which may be seen as an atomic analogue of a twin-photon interferometer, can be used to investigate the suitability of molecule dissociation processes -- such as the metastable hydrogen atoms H($2^2 S$)-H($2^2 S$) dissociation - for coherent twin-atom optics.Comment: 6 pages, 3 Figures. Final version accepted for publication in Europhysics Letter

Alloxan-induced diabetes delays repair in a rat model of closed tibial fracture

A closed fracture was performed on the left tibia of 3-month-old Wistar rats weighing 250 to 350 g that were either healthy (N = 24) or made diabetic with alloxan (N = 24) to investigate the effect of alloxan-induced diabetes on the course of bone fracture healing. Histomorphometric analysis of the fracture site was performed at 7, 14, 25, and 35 days. After 7 days, diabetic rats had significantly less cartilage (P = 0.045) and greater fibrous connective (P = 0.006) tissue formation at the fracture site compared to controls. In contrast, marked callus formation was seen in diabetic rats with significant osteogenesis (P = 0.011, P = 0.010, P = 0.010, respectively, for 14, 25, and 35 days) and chondrogenesis (P = 0.028, P = 0.033, P = 0.019) compared to controls. Radiographic analysis revealed a displaced fracture with poor bone fragment alignment and delayed consolidation at these times in the diabetic group. The levels of alkaline phosphatase were significantly higher in diabetic rats at 25 days (P = 0.009). These results suggest that the initial excessive formation of fibrous connective tissue associated with delay in chondrogenesis and osteogenesis may not provide suitable stability of the fractured site, contributing to the inappropriate alignment of fragments and an increase in the volume of callus in later stages of repair. The resulting displaced fracture in diabetic rats requires long periods for remodeling and complete bone consolidation

Comprehensive molecular landscape of cetuximab resistance in head and neck cancer cell lines

Cetuximab is the sole anti-EGFR monoclonal antibody that is FDA approved to treat head and neck squamous cell carcinoma (HNSCC). However, no predictive biomarkers of cetuximab response are known for HNSCC. Herein, we address the molecular mechanisms underlying cetuximab resistance in an in vitro model. We established a cetuximab resistant model (FaDu), using increased cetuximab concentrations for more than eight months. The resistance and parental cells were evaluated for cell viability and functional assays. Protein expression was analyzed by Western blot and human cell surface panel by lyoplate. The mutational profile and copy number alterations (CNA) were analyzed using whole-exome sequencing (WES) and the NanoString platform. FaDu resistant clones exhibited at least two-fold higher IC50 compared to the parental cell line. WES showed relevant mutations in several cancer-related genes, and the comparative mRNA expression analysis showed 36 differentially expressed genes associated with EGFR tyrosine kinase inhibitors resistance, RAS, MAPK, and mTOR signaling. Importantly, we observed that overexpression of KRAS, RhoA, and CD44 was associated with cetuximab resistance. Protein analysis revealed EGFR phosphorylation inhibition and mTOR increase in resistant cells. Moreover, the resistant cell line demonstrated an aggressive phenotype with a significant increase in adhesion, the number of colonies, and migration rates. Overall, we identified several molecular alterations in the cetuximab resistant cell line that may constitute novel biomarkers of cetuximab response such as mTOR and RhoA overexpression. These findings indicate new strategies to overcome anti-EGFR resistance in HNSCC.This work was supported by Barretos Cancer Hospital and the Public Ministry of Labor Campinas (Research, Prevention, and Education of Occupational Cancer) in Campinas, Brazil, CAPESDFATD (88887.137283/2017-00). INFG is the recipient of a FAPESP Ph.D. fellowship (2017/22305-9)

Prevalence of Streptococcus agalactiae colonization in pregnant women from the 18th Health Region of Paraná State

Introduction The aim of this study was to determine the prevalence of GBS colonization in pregnant women in a public health service. Methods A study of 496 pregnant women at 35-37 gestational weeks was conducted from September 2011 to March 2014 in 21 municipalities of the 18th Health Region of Paraná State. Vaginal and anorectal samples of each woman were plated on sheep blood agar, and in HPTH and Todd-Hewitt enrichment broths. Results Of the 496 pregnant women, 141 (28.4%) were positive for GBS based on the combination of the three culture media with vaginal and anorectal samples. The prevalence was 23.7% for vaginal samples and 21.9% for anorectal ones. Among the variables analyzed in this study, only urinary infection was a significant factor (0.026) associated with GBS colonization in women. Conclusions Based on these results, health units should performs universal screening of pregnant women and hospitals should provide adequate prophylaxis, when indicated

INDICADORES FECAIS DE BOVINOS NELORE ALIMENTADOS COM DIETAS DE ALTA PROPORÇÃO DE CONCENTRADO

O presente trabalho teve como objetivo avaliar os efeitos de dietas de alta proporção de concentrado sobre características fecais em 20 bovinos Nelore machos com idade de 28 meses, em delineamento inteiramente casualizado. Os tratamentos foram constituídos de dieta total mais bagaço in natura - DT+BIN (54,52% de sorgo moído, 10,94% de caroço de algodão, 18% de casca de soja, 2,54% de farelo de soja, 10% bagaço de cana in natura e 4% de núcleo farelado), milho grão inteiro - MGI (75% de milho grão inteiro, 10% de casca de soja e 15% de núcleo peletizado) e dieta total - DT (44,44% de sorgo moído, 16,70% de caroço de algodão, 28,86% de casca de soja e 10% de núcleo farelado). Para determinação do pH das fezes e do amido fecal, amostras de fezes foram coletadas do reto de cada bovino nos dias 54, 55, 56 e 57 de experimento no período da manhã. O pH fecal foi determinado após adição de 100 mL de água destilada deionizada em 15 g de fezes frescas úmidas com a introdução da ponta do eletrodo de um peagâmetro microprocessado. O restante da amostra foi colocado em gelo, para depois ser congelado. Com o intuito de avaliar ocorrências de distúrbios gastrintestinais, as fezes frescas dos animais nas baias experimentais individuais foram avaliadas diariamente durante todo o experimento em três períodos. Os valores médios em percentagem do amido fecal, matéria seca fecal, medida de pH para o local de fermentação do amido e consumo de amido/kg não foram influenciados (P>0,05) pelos tratamentos. A FDN das fezes e o escore de consistência fecal foram influenciados pelos tratamentos (P<0,05). A dieta MGI com menor teor de FDNfe apresentou menor escore de fezes e menor percentagem de FDN fecal. Porém, a percentagem de amido e pH fecal, MS fecal e o consumo do amido não foram afetados pelo teor de FDNfe nas rações. A concentração de FDN fecal foi igual para os tratamentos DT+BIN e DT. O menor teor de FDN fecal no tratamento MGI é função do menor consumo de FDN pelos animais e, possivelmente, da maior digestibilidade dessa dieta. Os animais do tratamento MGI apresentaram fezes com consistência mais mole, com o valor de escore de 2,92. As fezes dos bovinos do tratamento DT+BIN foram de consistência mais firme com valor de escore de 3,12, considerada normal, e a dos animais do tratamento DT foram de consistência mais dura com valor de escore de 3,20.  Houve uma relação consistente positiva entre amido fecal e eficiência alimentar e uma tendência de relação positiva entre amido fecal e GMD. Dieta de alta proporção de concentrado com adição de 10% de BIN na matéria seca proporciona maior freqüência de fezes com escore de consistência firme. PALAVRAS-CHAVE: amido; confinamento; fezes; ração