Reaction of rat connective tissue to mineral trioxide aggregate and diaket

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to compare the reaction of rat connective tissue to two root-end filling materials: white Mineral Trioxide Aggregate (WMTA) and Diaket.</p> <p>Methods</p> <p>Each of the materials was placed in dentine tubes and implanted subcutaneously in the dorsal connective tissue of 21 Wistar albino rats. Tissue biopsies were collected 7, 30, and 60 days after the implantation procedure. The specimens were processed and stained with hematoxylin and eosin and examined microscopically. After determining inflammatory cell numbers in sections from each specimen, inflammatory reaction scores were defined as follows: 0; no or few inflammatory cells (no reaction), 1; less than 25 cells (mild reaction), 2; 25 to 125 cells, (moderate reaction), and 3; 125 or more cells (severe reaction). Statistical analysis was performed using the Kruskal-Wallis and Mann-Whitney tests.</p> <p>Results</p> <p>There were statistically significant differences in the median inflammatory cell numbers throughout the three test periods, with the most severe degree of inflammation observed at the one-week period. Few cases of necrosis were observed with WMTA. Diaket exhibited the most severe degree of inflammation and necrosis. After 30 days, both materials provoked moderate inflammatory reaction. The eight-week period showed the least severe degree of inflammation in all groups.</p> <p>Conclusions</p> <p>It was concluded that WMTA exhibits a more favourable tissue response compared with Diaket which induced more severe inflammatory reaction than WMTA and the control.</p

In vitro analysis of the cytotoxicity and the antimicrobial effect of four endodontic sealers

<p>Abstract</p> <p>Introduction</p> <p>The aim of this study was to investigate <it>in vitro </it>the cytotoxicity and antibacterial properties of four different endodontic sealers using human periodontal ligament fibroblast cell proliferation and visual analysis of growth inhibition.</p> <p>Methods</p> <p>A silicone (GuttaFlow), silicate (EndoSequence BC), zinc oxide eugenol (Pulp Canal Sealer EWT) and epoxy resin (AH Plus Jet) based sealer were incubated with PDL fibroblasts (10⁴cells/ml, n = 6) up to 96 h. Cell proliferation (RFU) was determined by means of the Alamar Blue assay. Cell growth and morphology was visualized by means of fluorescent dyes. Possible antibacterial properties of the different sealers were visualized by means of SEM (<it>Enterococcus faecalis; Parvimonas micra</it>).</p> <p>Results</p> <p>Fibroblast proliferation depended on sealer and cultivation time. After 72 and 96 h GuttaFlow and EndoSequence BC showed relatively non-cytotoxic reactions, while Pulp Canal Sealer EWT and AH Plus Jet caused a significant decrease of cell proliferation (p < 0.001). Visualization of cell growth and morphology with various fluorescent dyes supplemented the results. No antibacterial effect of EndoSequence BC to <it>P. micra </it>was found, whereas GuttaFlow showed a weak, Pulp Canal Sealer EWT and AH Plus Jet extensive growth inhibition. Also, no antibacterial effect of GuttaFlow, EndoSequence BC or AH Plus Jet to <it>E. faecalis </it>could be detected.</p> <p>Conclusions</p> <p>These <it>in vitro </it>findings reveal that GuttaFlow and EndoSequence BC can be considered as biocompatible sealing materials. However, prior to their clinical employment, studies regarding their sealing properties also need to be considered.</p

Construction and in vivo assembly of a catalytically proficient and hyperthermostable de novo enzyme

Although catalytic mechanisms in natural enzymes are well understood, achieving the diverse palette of reaction chemistries in re-engineered native proteins has proved challenging. Wholesale modification of natural enzymes is potentially compromised by their intrinsic complexity, which often obscures the underlying principles governing biocatalytic efficiency. The maquette approach can circumvent this complexity by combining a robust de novo designed chassis with a design process that avoids atomistic mimicry of natural proteins. Here, we apply this method to the construction of a highly efficient, promiscuous, and thermostable artificial enzyme that catalyzes a diverse array of substrate oxidations coupled to the reduction of H2O2. The maquette exhibits kinetics that match and even surpass those of certain natural peroxidases, retains its activity at elevated temperature and in the presence of organic solvents, and provides a simple platform for interrogating catalytic intermediates common to natural heme-containing enzymes

Induction of eosinophil apoptosis by hydrogen peroxide promotes the resolution of allergic inflammation

Made available in DSpace on 2015-08-19T13:49:23Z (GMT). No. of bitstreams: 2 license.txt: 1914 bytes, checksum: 7d48279ffeed55da8dfe2f8e81f3b81f (MD5) ma_martins_etal_IOC-2105.pdf: 3830001 bytes, checksum: 2629ef32ff4c6dfb811625d5ef43b612 (MD5) Previous issue date: 2015Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Morfologia. Laboratório de Resolução da Resposta Inflamatória. Laboratório de Imunofarmacologia. Departamento de Bioquímica e Imunologia. Belo Horizonte, MG, Brasil.University of Edinburgh. The Queen’s Medical Research Institute. Medical Research Council Centre for Inflammation Research. Edinburgh, Scotland, UK.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Morfologia. Laboratório de Resolução da Resposta Inflamatória. Laboratório de Imunofarmacologia. Departamento de Bioquímica e Imunologia. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Morfologia. Laboratório de Resolução da Resposta Inflamatória. Laboratório de Imunofarmacologia. Departamento de Bioquímica e Imunologia. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Faculdade de Farmácia. Departamento de Análises Clínicas e Toxicológicas. Laboratório de Sinalização na Inflamação. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Microbiologia. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Inflamação. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Inflamação. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Inflamação. Rio de Janeiro, RJ, Brasil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Laboratório de Patologia Geral. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Faculdade de Farmácia. Departamento de Análises Clínicas e Toxicológicas. Laboratório de Sinalização na Inflamação. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Inflamação. Rio de Janeiro, RJ, Brasil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Morfologia. Laboratório de Resolução da Resposta Inflamatória. Belo Horizonte, MG, Brasil.University of Edinburgh. The Queen’s Medical Research Institute. Medical Research Council Centre for Inflammation Research. Edinburgh, Scotland, UK.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Bioquímica e Imunologia. Laboratório de Imunofarmacologia. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Morfologia. Laboratório de Resolução da Resposta Inflamatória. Laboratório de Imunofarmacologia. Departamento de Bioquímica e Imunologia. Belo Horizonte, MG, Brasil.Eosinophils are effector cells that have an important role in the pathogenesis of allergic disease. Defective removal of these cells likely leads to chronic inflammatory diseases such as asthma. Thus, there is great interest in understanding the mechanisms responsible for the elimination of eosinophils from inflammatory sites. Previous studies have demonstrated a role for certain mediators and molecular pathways responsible for the survival and death of leukocytes at sites of inflammation. Reactive oxygen species have been described as proinflammatory mediators but their role in the resolution phase of inflammation is poorly understood. The aim of this study was to investigate the effect of reactive oxygen species in the resolution of allergic inflammatory responses. An eosinophilic cell line (Eol-1) was treated with hydrogen peroxide and apoptosis was measured. Allergic inflammation was induced in ovalbumin sensitized and challenged mouse models and reactive oxygen species were administered at the peak of inflammatory cell infiltrate. Inflammatory cell numbers, cytokine and chemokine levels, mucus production, inflammatory cell apoptosis and peribronchiolar matrix deposition was quantified in the lungs. Resistance and elastance were measured at baseline and after aerosolized methacholine. Hydrogen peroxide accelerates resolution of airway inflammation by induction of caspase-dependent apoptosis of eosinophils and decrease remodeling, mucus deposition, inflammatory cytokine production and airway hyperreactivity. Moreover, the inhibition of reactive oxygen species production by apocynin or in gp91phox −/− mice prolonged the inflammatory response. Hydrogen peroxide induces Eol-1 apoptosis in vitro and enhances the resolution of inflammation and improves lung function in vivo by inducing caspase-dependent apoptosis of eosinophils

Biocompatibility of RealSeal, its primer and AH Plus implanted in subcutaneous connective tissue of rats

OBJECTIVE: This study tested rat connective tissue response to RealSeal, RealSeal primer or AH Plus after 7, 15, 30, 60 and 90 days of implantation. MATERIAL AND METHODS: Thirty Wistar rats had subcutaneous sockets created on their back and received four implants each of polyethylene tubes containing one of the materials tested according to the groups: AH (AH Plus Sealer); RS (RealSeal Sealer); RP (RealSeal Primer); CG (control group - empty tube). After histological processing, sections were analyzed to identify the presence of neutrophils, lymphocytes and plasma cells, eosinophils, macrophages and giant cells, as well as fibrous capsule and abscesses, by an examiner using light microscope. Kruskal-Wallis and multiple-comparisons test were used for statistical analysis. Significance level was set at 5%. RESULTS: Lymphoplasmacytic infiltrate scores significantly higher than those of the control group were observed at 14 and 60 days in AH group, and at 90 days in RS group (p<0.05). There were no differences in terms of presence of macrophages, giant cells, eosinophils, neutrophils or fibrosis. AH Plus group scored higher for abscesses at 7 days than after any other period (p=0.031). RP group scored higher for lymphoplasmacytic infiltrate at 14 days than at 90 days (p=0.04). CONCLUSION: The main contribution of this study was to demonstrate that issues involved with tissue tolerance of a Resilon-containing sealer, RealSeal Sealer, cannot be attributed to its primer content