Análise do comportamento de fibroblastos gengivais cultivados sobre diferentes tipos de membranas reabsorvíveis

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Programa de Pós-Graduação em Odontologia, Florianópolis, 2010Cirurgias para reconstrução de tecido mole que utilizam material autógeno aumentam a morbidade e o riscos de complicações com a segunda área cirúrgica. Como alternativa para eliminar esses inconvenientes, a engenharia tecidual busca encontrar um arcabouço ideal para carrear células e fatores de crescimento responsáveis pela criação de tecidos em ambiente in vitro. Dessa forma o objetivo deste estudo é analisar quatro membranas absorvíveis como potencial arcabouço para a engenharia de tecidos. Foram utilizados fibroblastos humanos gengivais provenientes de cultura primária. Quatro membranas foram utilizadas: Osseoguard®, Genderm®, ácido poli(ácido lactico-co-glicólico) (PLGA) e ácido poli(ácido lactico-co-glicólico) associado com hidroxiapatita (PLGA+HA). Testes de proliferação, análise da degradação através da microscopia eletrônica de varredura (MEV), teste de viabilidade celular (MTT) e análise do pH do meio de cultura foram os métodos utilizados para avaliar as membranas. Os índices de proliferação não foram estatisticamente significativos entre grupos, contudo todas as membranas possibilitaram a proliferação celular. A análise do MEV mostrou que as membranas com base polimérica (PLGA e PLGA + HA) apresentam características mais apropriadas a arcabouços para engenharia tecidual. Os níveis de viabilidade celular diminuíram e os níveis de pH foram similares para todos os grupos exceto o PLGA que se apresentou ácido. A membrana de PLGA + HA é a que apresenta melhores características biológicas e estruturais para funcionar como arcabouço para a engenharia de tecidos.Soft tissue reconstruction using autogenous material increases morbidity and risk of complications with the second surgical area, the donor site. As an alternative to eliminate these drawbacks, tissue engineering seeks to find an ideal scaffolds to wash cells and growth factors that are responsible for a tissue environment fabrication in vitro. Thus the aim of this study is to analyze four absorbable membranes as a potential scaffold for tissue engineering. Human gingival fibroblasts (HGF) from primary cell culture were used. Four types of bioabsorbable membranes were used as cell carrier: OsseoGuard®, Genderm®, poly (lactic-co-glycolic) acid (PLGA) and poly (lactic-co-glycolic) acid associated with hydroxyapatite (PLGA+HA). Proliferation assays, degradation analysis by scanning electron microscopy (SEM) cell viability assay (MTT) and pH analysis of the culture mediums were used to evaluate the membranes. The proliferation index was not statistically significant between groups, yet all the membranes allowed cell proliferation. The SEM analysis showed that the membranes based on polymers (PLGA and PLGA HA) have more appropriate scaffolds characteristics for tissue engineering. The level of cell viability decreased and the pH levels were similar for all groups except that PLGA. The PLGA+HA membrane has the best biological and structural functions as a scaffold for tissue engineering

Lactamas e nanopartículas de prata como potenciais agentes antibiofilme e antimicrobianos: estudo in vitro

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Programa de Pós-Graduação em Odontologia, Florianópolis, 2013.As doenças periodontal e peri-implantar são processos infecciosos, dependente da patogenicidade dos microrganimos responsáveis. A utilização de antibióticos tem sido frequente, associada terapias convencionais, para o combate dessas infecções, contudo seu uso indiscriminado tem gerado o aparecimento deresistência bacteriana. Como alternativa, compostos que inibem mecanismos regulatórios das bactérias veem sendo testados, tendo como alvo a inibição da virulência sem interferir com a viabilidade bacteriana.Dentro desta nova classe de antimicrobianos não convencionais destacam-se os compostos que atuam na inibição do biofilme bacteriano. Assim, o objetivo deste estudo é analisar a capacidade antibiofilme de três lactamas, derivadas de furanonas cuja a atividade contra o biofilme bacteriano e reconhecida, e de nanopartículas de prata, utilizadas em concentrações subinibitórias,na a formação de biofilmes deEnterococcus faecalissobre um material polimérico implantável. A atividade de três lactamas sintéticas, U 21-1, U 21-2 e U 27-2, foi avaliadasobre discos de PLGA-HA. e comparadas com as de concentrações subinibitórias de nanopartículas de prata (NpAg). Ensaios de inibição de aderência e formação de biofilme e observação ao MEV foram escolhidos para quantificar e qualificar a formação de biofilme de E.faecalis.A viabilidadede células cultivadas sobre o polímero foi acessada através de ensaios colorimétricos e confirmada pelo ensaio Live/Dead e a adesão das células foi caracterizada por microscopia confocal. Todos os compostos apresentaram taxas de redução de biofilme superiores à 99%, o que foi comprovado com as imagens obtidas pelo MEV. Nas CIM, os índices de viabilidade celular de todos os compostos foi superior ao preconizado para aprovação para uso clínico, tendo as lactamas apresentado resultados superiores aos das NpAg. Os resultados aqui apresentados indicam que lactamas e nanopartículas de prata apresentam excelente potencial para utilização no tratamento da doença periodontal e se associados ao PLGA-HA podem ser utilizadas na prevenção de peri-implantites. Abstract : Periodontal and peri-implant diseases are infection pathologies related to the pathogenicity of the microrganisms involved. The use of antibiotics has been frequently associated with conventional therapies for the combat these infections, however the widespread use of these antimicrobial compounds has led to the emergence of bacterial resistance. Alternatively, compounds that inhibit bacterial regulatory mechanismscontrolling virulence,havebeentested in the view of developing a new generation of antimicrobial drugstargeting inhibition of virulence without interfering with bacterial viability.Within this new class of antimicrobials some of the most promising are those interfering with bacterial biofilms.Here we analysed the effects of three novel synthetic lactams, derived from furanones whose antibiofilm activities are recognized, and of subinibitory concentrations of silver nanoparticles (AgNPs), on biofilms of Enterococcus faecalisformed over an Implantable polymeric material. The behavior of human cells cultured over this biomaterial in the presence of those compounds was also accessed, in view of developing functionalized implantable devices. Inhibition assays of adhesion and biofilm formation and SEM observation were used to quantify and qualify the biofilm formation of E. faecalis. Viability of cells cultured on the surface of this polymer was accessed via colorimetric assays and cell adhesion was characterized by confocal microscopy. All compounds showed biofilm inhibition rates higher than 99%, as acessed by CFU contings and in agreement with images obtained by SEM. At the CIM, human cells viability indexes of all compounds were higher than those recommended for approval in clinical use, with lactams showing better results than AgNPs. Results presented here indicate that lactams and silver nanoparticles have excellent potential for use in the treatment of periodontal disease and inassociation with PLGA-HA can be used in the prevention of peri-implantitis

Gingival peeling and periodontal aesthetics: a case report.

Melanic pigmentations (MP) are dark stains located on the masticatory mucosa. These pigmentations are consequence of the excess of melanin  production by  the  melanocytes  located  in  the  basal  layer  of  the epithelium, between epithelial cells and connective tissue cells. The MP of the periodontium are the results of the melanin granules transfer from the melanocytes to the keratinocytes, in a process called epidermal melanin.  This study aims to report a clinical case of dermabrasion for treatment of gingival melanin hyper pigmentation of a female patient, 21 years of age, non smoker, under orthodontic treatment and without systemic alterations. This patient attended the Clinic of Specialization in Periodontics of the Brazilian Association of Dentistry (ABO) with the aesthetic of her smile as the chief complain, due to the excess of melanin on the gingival tissues, in the anterior superior region.  The  epithelial  dermabrasion technique, with hand tools, promoted aesthetic results on the melanic depigmentation.Melanic pigmentations (MP) are dark stains located on the masticatory mucosa. These pigmentations are consequence of the excess of melanin  production by  the  melanocytes  located  in  the  basal  layer  of  the epithelium, between epithelial cells and connective tissue cells. The MP of the periodontium are the results of the melanin granules transfer from the melanocytes to the keratinocytes, in a process called epidermal melanin.  This study aims to report a clinical case of dermabrasion for treatment of gingival melanin hyper pigmentation of a female patient, 21 years of age, non smoker, under orthodontic treatment and without systemic alterations. This patient attended the Clinic of Specialization in Periodontics of the Brazilian Association of Dentistry (ABO) with the aesthetic of her smile as the chief complain, due to the excess of melanin on the gingival tissues, in the anterior superior region.  The  epithelial  dermabrasion technique, with hand tools, promoted aesthetic results on the melanic depigmentation

Effects of inorganic mercury exposure in the alveolar bone of rats: an approach of qualitative and morphological aspects

Pró-Reitoria de Pesquisa (PACI/PROPESP/UFPA/ Brazil), Brazilian National Council for Scientific and Technological Development (CNPq), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brazil (CAPES) – Finance Cod 001Background: In comparison to organic mercury (MeHg), the environmental inorganic mercury (IHg) can be found in some skin-lightening cosmestics were considered “harmless” for a long time. However, recent studies have shown that long-term exposure to low doses of IHg may affect biological systems. Therefore, this study investigated the effects of IHg long-term exposure to the alveolar bone of adult rats. Methods: Adult Wistar rats were distributed in control and HgCl2 exposed (0.375 mg/kg/day). After 45 days, the rats were euthanized and both blood and hemimandibles were collected. Total blood Hg levels were measured and both inorganic and organic components of the alveolar bone were determined through XRD and ATR-FTIR. The microstructure of the alveolar bone was assessed by using micro-CT and the morphometric analysis was performed by using stereomicroscopy. Results: Alterations in the physicochemical components of the alveolar bone of exposed animals were observed. The bone changes represented a tissue reaction at the microstructural level, such as bone volume increase. However, no significant dimensional changes (bone height) were observed. Conclusion: Exposure to IHg at this dose can promote microstructural changes and alteration in the organic and inorganic components in the alveolar bone.publishersversionpublishe

Quercus suber and Betula pendula outer barks as renewable sources of oleochemicals: A comparative study

A comparative study on the chemical composition of oak cork (Quercus suber L.) and corresponding industrial residues and birch (Betula pendula L.) outer bark is reported. Cork oak samples have lower extractives contents (6-9%) and higher contents of carbohydrates and lignin (23-27 and 33-38%, respectively) than those found for birch outer bark (40, 6 and 9%, respectively); suberin contents accounted for around 30% of cork, 11% of industrial cork powder and 45% of birch outer bark. Analysis of the suberin monomeric composition revealed that C18 and C22 omega-hydroxyfatty acids (including mid-chain epoxy- and dihydroxy-derivatives), followed by alpha,omega-dicarboxylic acids, are the main components in both suberins, with 9,10-epoxy-18-hydroxyoctadecanoic, 18-hydroxyoctadec-9-enoic, 9,10,18-trihydroxyoctadecanoic and octadec-9-enoic acids as the major components. The differences in the relative amounts of these acids in the suberin samples and the impact on the potential exploitation of the different industrial by-products are discussed. (C) 2008 Elsevier B.V All rights reserved.WaCheUp project - STRP 013896EC/6FP - priority 3, NM

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Combined fit to the spectrum and composition data measured by the Pierre Auger Observatory including magnetic horizon effects

The measurements by the Pierre Auger Observatory of the energy spectrum and mass composition of cosmic rays can be interpreted assuming the presence of two extragalactic source populations, one dominating the flux at energies above a few EeV and the other below. To fit the data ignoring magnetic field effects, the high-energy population needs to accelerate a mixture of nuclei with very hard spectra, at odds with the approximate E$^{-2}$ shape expected from diffusive shock acceleration. The presence of turbulent extragalactic magnetic fields in the region between the closest sources and the Earth can significantly modify the observed CR spectrum with respect to that emitted by the sources, reducing the flux of low-rigidity particles that reach the Earth. We here take into account this magnetic horizon effect in the combined fit of the spectrum and shower depth distributions, exploring the possibility that a spectrum for the high-energy population sources with a shape closer to E$^{-2}$ be able to explain the observations

Studies of the mass composition of cosmic rays and proton-proton interaction cross-sections at ultra-high energies with the Pierre Auger Observatory

In this work, we present an estimate of the cosmic-ray mass composition from the distributions of the depth of the shower maximum (Xmax) measured by the fluorescence detector of the Pierre Auger Observatory. We discuss the sensitivity of the mass composition measurements to the uncertainties in the properties of the hadronic interactions, particularly in the predictions of the particle interaction cross-sections. For this purpose, we adjust the fractions of cosmic-ray mass groups to fit the data with Xmax distributions from air shower simulations. We modify the proton-proton cross-sections at ultra-high energies, and the corresponding air shower simulations with rescaled nucleus-air cross-sections are obtained via Glauber theory. We compare the energy-dependent composition of ultra-high-energy cosmic rays obtained for the different extrapolations of the proton-proton cross-sections from low-energy accelerator data

Study of downward Terrestrial Gamma-ray Flashes with the surface detector of the Pierre Auger Observatory

The surface detector (SD) of the Pierre Auger Observatory, consisting of 1660 water-Cherenkov detectors (WCDs), covers 3000 km2 in the Argentinian pampa. Thanks to the high efficiency of WCDs in detecting gamma rays, it represents a unique instrument for studying downward Terrestrial Gamma-ray Flashes (TGFs) over a large area. Peculiar events, likely related to downward TGFs, were detected at the Auger Observatory. Their experimental signature and time evolution are very different from those of a shower produced by an ultrahigh-energy cosmic ray. They happen in coincidence with low thunderclouds and lightning, and their large deposited energy at the ground is compatible with that of a standard downward TGF with the source a few kilometers above the ground. A new trigger algorithm to increase the TGF-like event statistics was installed in the whole array. The study of the performance of the new trigger system during the lightning season is ongoing and will provide a handle to develop improved algorithms to implement in the Auger upgraded electronic boards. The available data sample, even if small, can give important clues about the TGF production models, in particular, the shape of WCD signals. Moreover, the SD allows us to observe more than one point in the TGF beam, providing information on the emission angle