Fluoride release profile of a nanofilled resin-modified glass ionomer cement

The present study aimed to compare the fluoride (F-) release pattern of a nanofilled resin-modified glass ionomer cement (GIC) (Ketac N100 - KN) with available GICs used in dental practice (resin-modified GIC - Vitremer - V; conventional GIC - Ketac Molar - KM) and a nanofilled resin composite (Filtek Supreme - RC). Discs of each material (n=6) were placed into 4 mL of deionized water in sealed polyethylene vials and shaken, for 15 days. F- release (μg F-/cm²) was measured each day using a fluoride-ion specific electrode. Cumulative F- release means were statistically analyzed by linear regression analysis. In order to analyze the differences among materials and the influence of time in the daily F- release, 2-way ANOVA test was performed (α=0.05). The linear fits between the cumulative F- release profiles of RC and KM and time were weak. KN and V presented a strong relationship between cumulative F- release and time. There were significant differences between the daily F- release overtime up to the third day only for GICs materials. The daily F- release means for RC were similar overtime. The results indicate that the F- release profile of the nanofilled resin-modified GIC is comparable to the resin-modified GIC.O presente estudo teve como objetivo comparar o padrão de liberação de fluoreto (F-) de um cimento de ionômero de vidro (CIV) nanoparticulado modificado por resina (Ketac N100 - KN) com CIVs disponíveis na prática clínica (CIV modificado por resina - Vitremer - V; CIV convencional - Ketac Molar - KM) e uma resina composta nanoparticulada (Filtek Supreme - RC). Discos de cada material (n=6) foram imersos em 4 mL de água deionizada em frascos de polietileno e agitados durante 15 dias. A liberação de F- (μg F-/cm²) foi medida a cada dia utilizando um eletrodo de F- específico. Os valores de liberação cumulativa de F- foram analisados estatisticamente por análise de regressão linear. Com o objetivo de analisar as diferenças entre os materiais e a influência do tempo na liberação diária de F- foi aplicado o teste ANOVA a dois critérios (α=0,05). A relação entre os padrões de liberação de cumulativo de F- da RC e KM e o tempo foram fracas. Os materiais KN e V apresentaram uma relação forte entre a liberação cumulativa de F- e o tempo. Diferenças significativas foram observadas entre a liberação diária de F- até o terceiro dia somente para os cimentos ionoméricos. Os resultados indicam que o padrão de liberação de F- do CIV modificado por resina nanoparticulado é semelhante ao CIV modificado por resina

Bilateral mesiodens in monozygotic twins: 3D diagnostic and management

Mesiodens is the most frequent type of supernumerary tooth and may occur in several forms, causing different local disorders, such as impaction of the anterior permanent teeth. High-resolution three-dimensional (3D) images have improved the diagnosis and treatment plan of patients with impacted and supernumerary teeth. The purpose of this paper was to report a case of two mesiodens in monozygotic twin boys with appropriate 3D diagnostic and treatment pla

The Grb10/Nedd4 Complex Regulates Ligand-Induced Ubiquitination and Stability of the Insulin-Like Growth Factor I Receptor

The adapter protein Grb10 belongs to a superfamily of related proteins, including Grb7, -10, and -14 and Caenorhabditis elegans Mig10. Grb10 is an interacting partner of the insulin-like growth factor I receptor (IGF-IR) and the insulin receptor (IR). Previous work showed an inhibitory effect of mouse Grb10 (mGrb10α) on IGF-I-mediated mitogenesis (A. Morrione et al., J. Biol. Chem. 272:26382-26387, 1997). With mGrb10α as bait in a yeast two-hybrid screen, mouse Nedd4 (mNedd4-1), a ubiquitin protein ligase, was previously isolated as an interacting protein of Grb10 (A. Morrione et al., J. Biol. Chem. 274:24094-24099, 1999). However, Grb10 is not ubiquitinated by Nedd4 in cells. Here we show that in mouse embryo fibroblasts overexpressing Grb10 and the IGF-IR (p6/Grb10), there is a strong ligand-dependent increase in ubiquitination of the IGF-IR compared with that in parental cells (p6). This increased ubiquitination is associated with a shorter half-life and increased internalization of the IGF-IR. The IGF-IR is stabilized following treatment with both MG132 and chloroquine, indicating that both the proteasome and lysosomal pathways mediate degradation of the receptor. Ubiquitination of the IGF-IR likely occurs at the plasma membrane, prior to the formation of endocytic vesicles, as it is insensitive to dansylcadaverine, an inhibitor of early endosome formation in IGF-IR endocytosis. Grb10 coimmunoprecipitates with the IGF-IR and endogenous Nedd4 in p6/Grb10 cells, suggesting the presence of a Grb10/Nedd4/IGF-IR complex. Ubiquitination of the IGF-IR in p6/Grb10 cells is severely impaired by overexpression of a catalytically inactive Nedd4 mutant (Nedd4-CS), which also stabilizes the receptor. Likewise, overexpression of a Grb10 mutant lacking the Src homology 2 (SH2) domain impaired ubiquitination of the IGF-IR in parental p6 and p6/Grb10 cells, indicating that Grb10 binding to Nedd4 is critical for ubiquitination of the receptor. These results suggest a role for the Grb10/Nedd4 complex in regulating ubiquitination and stability of the IGF-IR, and they suggest that Grb10 serves as an adapter to form a bridge between Nedd4 and the IGF-IR. This is the first demonstration of regulation of stability of a tyrosine kinase receptor by the Nedd4 (HECT) family of E3 ligases

Design and optimization of polymer nanoshuttles for nanomedicine

Current advances in nanotechnology hold the promises to greatly impact on current medical practice. Since nanometric materials interact with cells, tissue and organs at a molecular level, they may be used as probes for ultrasensitive molecular sensing and diagnostic imaging or carriers for drug and gene delivery. However, along with the excitement that has driven the development of novel nanocarriers, there have been increasing concerns regarding the risks these materials may generate. As these nanostructures are intentionally engineered to target specific cells or tissues, it is imperative to ensure their safety. The optimal design of safe and functional nanocarriers for medicine requires a better understanding of the interaction between the physical-chemistry properties of the nanoparticle surface with the complex protein machinery existing at the cell membrane. In particular the effect of the particles properties (charge, shape, protein coating) on the mechanism of cellular uptake is highly relevant both to assess the real biological risks coupled with the use of nanomaterial (nanopathology and nanotoxicology) and to engineer carriers able to improve the medical practice. The nanometric size and the surface molecular decoration may activate mechanisms of cellular uptake different from those commonly used by cells: these open the possibility to activated/modulated the membrane crossing by tuning chemical-physical properties of nanometric materials. In this work, the design and production of novel degradable polymeric nanocavities via layer-by-layer and temperature induced phase separation technology will be presented along with a detailed characterization of their in vitro performances. Furthermore, possible mechanisms of cellular uptake will be discussed and critically presented. The effect of surface bioconjugation on cell membrane crossing will be exploited and elucidated. Particular attention will be devoted to surface molecular decoration able to guide the nanoparticle throughout the cytosol

Confined Gelatin Dehydration as a Viable Route to Go beyond Micromilling Resolution and Miniaturize Biological Assays

Nowadays, microfluidic channels of a few tens of micrometers are required and widely used in many fields, especially for surface-processing applications and miniaturization of biological assays. Herein, we selected micromilling as a low-cost technology and proposed an approach capable of overcoming its limitations; in fact, microstructures below 20-30 m in depth are difficult to obtain, and the manufacturing error is rather high, as it is inversely proportional to the depth. Indeed, the proposed method uses a confined dehydration process of a patterned gelatin substrate fabricated via replica molding onto a micromilled poly(methyl methacrylate) substrate to produce a gelatin master with demonstrated final micrometric features down to 3 m for the channel depth and, in specific configurations, down to 5 m for the channel width. Finally, we demonstrated the ability to flux liquids in miniaturized microfluidic devices and fabricated and tested - as an example - micrometric microstructures arrays connected via microchannels for biological assay

Hepatic steatosis is uncommon in children with chronic hepatitis B

Differently from chronic hepatitis C, factors associated with hepatic steatosis in children with chronic hepatitis B are not clearly elucidated. Objective Aim of this study was to investigate prevalence of steatosis at liver biopsy in HBV-infected children. Study design A retrospective study including 56 children with chronic hepatitis B undergoing liver biopsy at median age of 8.1 years. In all patients demographic, anthropometric, clinical and laboratory data were evaluated at the time of liver biopsy. Results Steatosis was present in 2 (4%) children. BMI was significantly higher in 2 patients with steatosis compared with those without steatosis. Demographic, biochemical and virological parameters did not differ between children with and those without steatosis. Conclusions Liver steatosis in HBV-infected children seems to be related to obesity and metabolic factors rather than to viral factors. Detection of steatosis in non-obese children with HBV infection requires a careful investigation to rule out other causes of fatty liver

Energetics of ligand-receptor binding affinity on endothelial cells: An in vitro model

Targeted therapies represent a challenge in modern medicine. In this contest, we propose a rapid and reliable methodology based on Isothermal Titration Calorimetry (ITC) coupled with confluent cell layers cultured around biocompatible templating microparticles to quantify the number of overexpressing receptors on cell membrane and study the energetics of receptor-ligand binding in near-physiological conditions. In the in vitro model here proposed we used the bEnd3 cell line as brain endothelial cells to mimic the blood brain barrier (BBB) cultured on dextran microbeads ranging from 67 μm to 80 μm in size (Cytodex) and the primary human umbilical vein cells (HUVEC) for comparison. The revealed affinity between transferrin (Tf) and transferrin receptor (TfR) in both systems is very high, Kd values are in the order of nM. Conversely, the value of TfRs/cell reveals a 100-fold increase in the number of TfRs per bEnd3 cells compared to HUVEC cells. The presented methodology can represent a novel and helpful strategy to identify targets, to address drug design and selectively deliver therapeutics that can cross biological barriers such as the blood brain barrier

Energetics of ligand-receptor binding affinity on endothelial cells: An in vitro model

Targeted therapies represent a challenge in modern medicine. In this contest, we propose a rapid and reliable methodology based on Isothermal Titration Calorimetry (ITC) coupled with confluent cell layers cultured around biocompatible templating microparticles to quantify the number of overexpressing receptors on cell membrane and study the energetics of receptor-ligand binding in near-physiological conditions. In the in vitro model here proposed we used the bEnd3 cell line as brain endothelial cells to mimic the blood brain barrier (BBB) cultured on dextran microbeads ranging from 67 μm to 80 μm in size (Cytodex) and the primary human umbilical vein cells (HUVEC) for comparison. The revealed affinity between transferrin (Tf) and transferrin receptor (TfR) in both systems is very high, Kd values are in the order of nM. Conversely, the value of TfRs/cell reveals a 100-fold increase in the number of TfRs per bEnd3 cells compared to HUVEC cells. The presented methodology can represent a novel and helpful strategy to identify targets, to address drug design and selectively deliver therapeutics that can cross biological barriers such as the blood brain barrier