REABSORÇÃO CONDILAR INTERNA DA ARTICULAÇÃO TEMPOROMANDIBULAR NO PACIENTE ADOLESCENTE

A reabsorção condilar interna no adolescente (RCIA) é uma doença progressiva que afeta a articulação temporomandibular (ATM) e que pode resultar em maloclusão, deformidade facial, disfunção de ATM e dor. O aparecimento desta doença ocorre entre os 10 e os 15 anos, sendo mais freqüente em adolescentes do sexo feminino. Esses pacientes apresentam sinais clínicos característicos como: ângulo do plano oclusal e do plano mandibular aumentados, retrusão progressiva da mandíbula e maloclusão Classe II, com ou sem mordida aberta. Nos exames de imagem (tomografia computadorizada e ressonância magnética), observa-se reabsorção interna dos côndilos e deslocamento dos discos articulares da ATM. Tendo em vista a dificuldade em determinar a causa da RCIA e a importância em eliminar a dor e melhorar a função mastigatória, este estudo se propôs a avaliar as alterações promovidas no posicionamento mandibular, a sintomatologia dolorosa e a estabilidade do tratamento da RCIA, utilizando o protocolo de tratamento (Dr. Larry M. Wolford) em pacientes adolescentes submetidos a cirurgia de reposicionamento do disco articular e cirurgia ortognática, realizadas no mesmo ato cirúrgico. Neste estudo retrospectivo, foram avaliadas as telerradiografias laterais adquiridas na avaliação inicial (T1), pré-cirúrgica (T2), pós-cirúrgica imediata (T3) e de maior acompanhamento, com pelo menos um ano pós-cirurgia (T4) e questionários de dor e função mandibular de uma amostra de 24 pacientes com maloclusão de Classe II (20 do sexo feminino e 4 do sexo masculino) diagnosticados com RCIA, os quais foram submetidos ao protocolo de tratamento composto pela cirurgia de reposicionamento do disco articular da ATM concomitantemente à cirurgia ortognática. O protocolo de tratamento utilizado mostrou-se bastante positivo, uma vez que a estabilidade foi adquirida e uma melhora significativa nos níveis de dor e função mandibular foram atingidos. O tratamento dos pacientes diagnosticados com RCIA, através do protocolo de tratamento proposto, é um procedimento estável e atua diretamente em um ganho na redução da dor.

Segmentação fuzzy de objetos tridimensionais com propriedades texturais

Digital image segmentation is the process of assigning distinct labels to different objects in a digital image, and the fuzzy segmentation algorithm has been used successfully in the segmentation of images from several modalities. However, the traditional fuzzy segmentation algorithm fails to segment objects that are characterized by textures whose patterns cannot be successfully described by simple statistics computed over a very restricted area. In this paper we present an extension of the fuzzy segmentation algorithm that achieves the segmentation of textures by employing adaptive affinity functions as long as we extend the algorithm to tridimensional images. The adaptive affinity functions change the size of the area where they compute the texture descriptors, according to the characteristics of the texture being processed, while three dimensional images can be described as a finite set of two-dimensional images. The algorithm then segments the volume image with an appropriate calculation area for each texture, making it possible to produce good estimates of actual volumes of the target structures of the segmentation process. We will perform experiments with synthetic and real data in applications such as segmentation of medical imaging obtained from magnetic rosonance

Análise estrutural e avaliação do efeito condroitim sulfato extraído de tilápia (Oreochromis niloticus) em modelo de peritonite aguda

Chondroitin sulfate (CS) is a naturally glycosaminoglycan found in the extracellular matrix of connective tissues and it may be extracted and purified those tissues. CS is involved in various biological functions, which may be related to the having structural variability, despite the simplicity of the linear chain structure from this molecule. Researches in biotechnology and pharmaceutical field with wastes from aquaculture has been developed in Brazil. In recent decades, tilapia (Oreochromis niloticus), native fish from Africa, has been one of the most cultivated species in various regions of the world, including Brazil. The tilapia farming is a cost-effective activity, however, it generates large amount of wastes that are discarded by producers. It is understood that waste from tilapia can be used in research as a source of molecules with important biotechnological applications, which also helps in reducing environmental impacts and promote the development of an ecofriendly activity. Thus, nile tilapia viscera were subjected to proteolysis, then the glycosaminoglycans were complexed with ion exchange resin (Lewatit), it was fractionated with increasing volumes of acetone and purified by ion exchange chromatography DEAE-Sephacel. Further, the fraction was analyzed by agarose gel electrophoresis and nuclear magnetic resonance (NMR). The electrophoretic profile of the compound together the analysis of 1H NMR spectra and the HSQC correlation allow to affirm that the compound corresponds to a molecule like chondroitin sulfate. MTT assay was used to assess cell viability in the presence of CS tilapia isolated and showed that the compound is not cytotoxic to normal cells such as cells from the mouse embryo fibroblast (3T3). Then, this compound was tested for the ability to reduce the influx of leukocytes in model of acute peritonitis (in vivo) induced by sodium thioglycolate. In this context, it was done total and differential leukocytes counting in the blood and peritoneal fluid collected respectively from vena cava and the peritoneal cavity of the animals subjected to the experiment. The chondroitin sulfate for the first time isolated from tilapia (CST ) was able to reduce the migration of leukocytes to the peritoneal cavity of inflamed mice until 80.4 per cent at a dose 10µg/kg. The results also show that there was a significant reduction (p<0.001) of the population of polymorphonuclear leukocytes from peritoneal cavity in the three tested doses (0.1µg/kg; 1µg/kg and 10µg/kg) when it was compared to the positive control (just thioglycolate). Therefore, since the CST structure and mechanism of action has been completely elucidated, this compound may have potential for therapeutic use in inflammatory diseases

Alquilação de tolueno com propeno, através de complexo ferro (II) ᵦ- diimina homogêneo e heterogeneizado em MCM-41, Al-MCM-41 e SBA-15

This work describes the synthesis and aplication of homogeneous and heterogenized iron catalysts in the alkylation reaction of toluene with propene, empolying experimental design. The homogenous complex was obtained trough the synthesis of the organic ligand folowed by the complexation of the iron(II) chloride. As to the heterogenized complexes, first were synthetized the inorganic supports (SBA-15, MCM-41 and Al-MCM-41). Then, it was synthetized the ligand again, that through funcionalization with chloropropyltrimethoxysilane (CPTMS), was anchored on the support previously calcinated. To these anchored ligands, was complexed the iron(II) chloride, previously solubilizated in tetrahydrofuran (THF). The organic ligand characterization was accomplished trough nuclear magnetic resonance (NMR) and Infrared spectroscopy (IV). The supports were characterized with x-ray diffraction (DRX), texture analysis with nitrogen adsorption/desorption (before and after the anchoring), termogravimetric analysis (TG) and infrared (IV). The metalic content was quantified trough the atomic absorption spectrophotometry (AAS). The complexes were tested in catalytic reactions emolying ethylaluminium sesquichloride (EASC) as co-catalyst in steel reactor, under mecanic stirring. The reaction conditions ranged from 4 to 36 ◦C, with many aluminum/iron ratios. The catalysts were actives in homogeneous and heterogenized ways. The homogenous catalytic complex showed a maximum turnover frequency (TOF) of 8.63 ×103 · h −1 , while, in some conditions, the anchored complexes showed better results, with TOF of until 8.08 ×103 · h −1 . Aditionally, it was possible to determine an equation, to the homogenous catalyst, that describes the product quantity in function of reacional temperature and aluminum/iron ratio.

Desenvolvimento e avaliação tribológica de emulsão O/A a partir de óleo vegetal epoxidado para aplicação em fluídos de corte

The cutting fluids are lubricants used in machining processes, because they present many benefits for different processes. They have many functions, such as lubrication, cooling, improvement in surface finishing, besides they decreases the tool wear and protect it against corrosion. Therefore due to new environment laws and demand to green products, new cutting fluids must be development. These shall be biodegradable, non-toxic, safety for environment and operator healthy. Thus, vegetable oils are a good option to solve this problem, replacing the mineral oils. In this context, this work aimed to develop an emulsion cutting fluid from epoxidized vegetable oil, promoting better lubrication and cooling in machining processes, besides being environment friendly. The methodology was divided in five steps: first one was the biolubricant synthesis by epoxidation reaction. Following this, the biolubricant was characterized in terms of density, acidity, iodo index, oxirane index, viscosity, thermal stability and chemical composition. The third step was to develop an emulsion O/A with different oil concentration (10, 20 and 25%) and surfactant concentration (1, 2.5 and 5%). Also, emulsion stability was studied. The emulsion tribological performance were carried out in HFRR (High Frequency Reciprocating Rig), it consists in ball-disc contact. Results showed that the vegetable based lubricant may be synthesized by epoxidationreaction, the spectra showed that there was 100% conversion of the epoxy rings unsaturations. In regard the tribological assessment is observed that the percentage of oil present in the emulsion directly influenced the film formation and coefficient of friction for higher concentrations the film formation process is slow and unstable, and the coefficient of friction. The high concentrations of surfactants have not improved the emulsions tribological performance. The best performance in friction reduction was observed to emulsion with 10% of oil and 5% of surfactant, its average wear scar was 202 μm.

Síntese de zeólitas utilizando cátions orgânicos a base de um anel imidazólio como agentes direcionadores de estruturas em meio fluorídrico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

Tensoativo derivado do ácido cítrico: síntese e aplicação em fluidos de perfuração de emulsão inversa

This work describes the synthesis and study of the application of a new surfactant (Triester Lipophilic – TEL) obtained by citric acid with octanol. It is reaction was followed by thin layer chromatography (TLC) and after purification the product was characterized by proton and 13 – carbon nuclear magnetic resonance spectroscopy ( H and 13C NMR), thermogravimetric analysis (TGA) and surface tension analysis of oil-in-water emulsions. The TEL performance as surfactant in ester, n-paraffin and biodiesel based drilling fluids on the 70/30 and 60/40 water- oil rations (WOR) was evaluated by comparative tests of two commercial products used in the fields. These drilling fluids were aged in roller oven at 200 0 F during 16 h. The rheological and electric stability measurements were carried out at 135 ºF, the phase separation was evaluated after seven days at rest and the filtrate volume of drilling fluids was determined at high temperature and high pressure. The rheological behavior of the drilling fluids was evaluated by the flow curves. The results showed that the drilling fluids studied here presented Binghamian behavior as well as the used in the oil fields. The laboratory tests showed that the TEL reduced the filtrate volume and promoted the enhance of the thermal and mechanical stabilities.

Interações da trancinolona com ciclodextrinas em sistemas multicomponentes

Triamcinolone is a relevant anti-inflammatory costicosteroid drug, used mainly by injectable suspensions due its poor water solubility. The association of triamcinolone with cyclodextrins and co-solvents (triethanolamine TEA and N-methylpirrolidone NMP) was held to solubilize the drug and explain the involved interactions. Phase-solubility diagrams showed that triamcinolone was solubilized forming incredible stable complexes with cyclodextrins, in which bests results were observed applying randomyl-methylated-beta-cyclodextrin (RMβCD) (161 fold on increased solubility). The co-solvents TEA and NMP also enhanced drug solubility 1.4 and 6.7 fold, respectively. The association of both co-solvents with CDs seems decreased complexation stability, but enables higher amount of uncomplexed drug. Experimental magnetic resonance 2D-ROESY and theoretical molecular modeling studies demonstrated TRI-CDs interactions and elucidated the structure of formed complex, which occurred due to the inclusion of ring A of TRI on CDs cavity. Physicochemical aspects of solid binary and ternary complexes prepared by spray drying were assessed by using FTIR, X-ray diffraction and SEM photographs. Dissolution studies showed that binary and ternary associations presented higher dissolution efficacy in detrimental to pure drug system. In addition, the ternary complex containing TEA and RMβCD allowed drug dissolution faster than binary complex with RMβCD. Therefore, given the higher solubility and drug dissolution rate, binary and ternary complexes are new raw materials with great potential for pharmaceuticals containing triamcinolone.

Catalisadores bifuncionais à base de silicoaluminofosfato e fosfatos de nióbio para emprego em reações de hidroisomerização e hidrocraqueamento do n-hexadecano

Lubricants and cutting middle distillates typically have large amounts of n-paraffins to increase its freezing point and fluidity. Accordingly, the removal of n-paraffins of long chain lubricants oils and diesel is essential to get a product with good cold flow properties. The development of new catalysts, which exhibit thermal stability and catalytic activity for the hydroisomerization reaction is still a challenge. Thus, silicoaluminophosphates (SAPO) were synthesized by different routes. Have been used also post-synthesis treatment for obtaining hybrid structures and others synthesis have been carried out with mesoporous template (soft and hard-template). Therefore, SAPO have been impregnated with H2PtCl6 solution by the incipient wetness method. Then assessments of catalytic activities in hydroisomerization and hydrocracking reactions of hexadecane have been held. Besides SAPO, niobium phosphate - NbP - were also impregnated with platinum and evaluated in the same reaction. After impregnation, these catalysts have been characterized by X-ray diffraction (XRD), nitrogen adsorption, infrared spectroscopy with adsorbed pyridine (IV-PY), scanning electron microscopy (SEM) and resonance nuclear magnetic 29Si (29Si-NMR). The characterization results by XRD have shown that it has been possible to obtain mesoporous SAPOs. However, for the syntheses with soft template there was collapse of the structure after removal of the organic template. Even so, these catalysts have been actives. It was possible to obtain hybrid materials through the synthesis of SAPO-11 made with hard templates and by means of post-synthesis treatments samples of SAPO-11. Moreover, NbP has shown characteristic XRD of amorphous materials, with high acidity and were active in the conversion of hexadecane.

Catalisadores bifuncionais à base de silicoaluminofosfato e fosfatos de nióbio para emprego em reações de hidroisomerização e hidrocraqueamento do n-hexadecano

Lubricants and cutting middle distillates typically have large amounts of n-paraffins to increase its freezing point and fluidity. Accordingly, the removal of n-paraffins of long chain lubricants oils and diesel is essential to get a product with good cold flow properties. The development of new catalysts, which exhibit thermal stability and catalytic activity for the hydroisomerization reaction is still a challenge. Thus, silicoaluminophosphates (SAPO) were synthesized by different routes. Have been used also post-synthesis treatment for obtaining hybrid structures and others synthesis have been carried out with mesoporous template (soft and hard-template). Therefore, SAPO have been impregnated with H2PtCl6 solution by the incipient wetness method. Then assessments of catalytic activities in hydroisomerization and hydrocracking reactions of hexadecane have been held. Besides SAPO, niobium phosphate - NbP - were also impregnated with platinum and evaluated in the same reaction. After impregnation, these catalysts have been characterized by X-ray diffraction (XRD), nitrogen adsorption, infrared spectroscopy with adsorbed pyridine (IV-PY), scanning electron microscopy (SEM) and resonance nuclear magnetic 29Si (29Si-NMR). The characterization results by XRD have shown that it has been possible to obtain mesoporous SAPOs. However, for the syntheses with soft template there was collapse of the structure after removal of the organic template. Even so, these catalysts have been actives. It was possible to obtain hybrid materials through the synthesis of SAPO-11 made with hard templates and by means of post-synthesis treatments samples of SAPO-11. Moreover, NbP has shown characteristic XRD of amorphous materials, with high acidity and were active in the conversion of hexadecane.

Elucidação molecular e micelar dos superagregados de anfotericina B

A Anfotericina B (AmB) é amplamente utilizada no tratamento de infecções fúngicas sistêmicas. No entanto, a sua utilização é limitada devido a sua elevada toxicidade aguda e crônica. Os superagregados de AmB (H-AmB) obtido pelo processo de aquecimento controlado apresentam um potencial reduzido de toxicidade quando comparados à Anfotericina B micelar não aquecida (M-AmB). Diante do exposto, o objetivo deste estudo foi avaliar as características físico-químicas do processo de formação dos superagregados após a liofilização do H-AmB, por meio de técnicas tais como a calorimetria de exploratória diferencial (DSC), termogravimetria (TG) e análise térmica diferencial (DTG), ressonância magnética nuclear (RMN), espalhamento dinâmico de luz (DLS) e difração de raios X (DRX). Os dados de DLS indicaram um tamanho de aproximadamente 260 nm deste novo sistema, sendo este tamanho compatível e viável para administração intravenosa. A análise de DRX demonstrou a formação de um novo estado cristalino do sistema micelar, podendo este estar relacionado a presença de grande proporção de desoxicolato de sódio (NaDC) na formulação. O aquecimento do NaDC resulta na formação de uma estrutura helicoidal intermolecular, promovendo desta forma o aumento da agregação micelar e consequentemente aumento de seu tamanho. Os estudos das análises térmicas demonstraram que o processo de aquecimento não influência no comportamento das amostras. Os dados de RMN da H-AmB demonstraram a presença de ácido desoxicólico além do NaDC. O ácido desoxicólico é formado após o processo de aquecimento e sugere-se que o equilíbrio entre ambas as moléculas seja responsável pela redução da toxicidade da AmB. Os resultados aqui apresentados sugerem que o processo de aquecimento controlado altera a organização estrutural das micelas, resultando na diminuição da toxicidade, na melhoria da estabilidade térmica e na manutenção da atividade.

Elucidação molecular e micelar dos superagregados de anfotericina B

A Anfotericina B (AmB) é amplamente utilizada no tratamento de infecções fúngicas sistêmicas. No entanto, a sua utilização é limitada devido a sua elevada toxicidade aguda e crônica. Os superagregados de AmB (H-AmB) obtido pelo processo de aquecimento controlado apresentam um potencial reduzido de toxicidade quando comparados à Anfotericina B micelar não aquecida (M-AmB). Diante do exposto, o objetivo deste estudo foi avaliar as características físico-químicas do processo de formação dos superagregados após a liofilização do H-AmB, por meio de técnicas tais como a calorimetria de exploratória diferencial (DSC), termogravimetria (TG) e análise térmica diferencial (DTG), ressonância magnética nuclear (RMN), espalhamento dinâmico de luz (DLS) e difração de raios X (DRX). Os dados de DLS indicaram um tamanho de aproximadamente 260 nm deste novo sistema, sendo este tamanho compatível e viável para administração intravenosa. A análise de DRX demonstrou a formação de um novo estado cristalino do sistema micelar, podendo este estar relacionado a presença de grande proporção de desoxicolato de sódio (NaDC) na formulação. O aquecimento do NaDC resulta na formação de uma estrutura helicoidal intermolecular, promovendo desta forma o aumento da agregação micelar e consequentemente aumento de seu tamanho. Os estudos das análises térmicas demonstraram que o processo de aquecimento não influência no comportamento das amostras. Os dados de RMN da H-AmB demonstraram a presença de ácido desoxicólico além do NaDC. O ácido desoxicólico é formado após o processo de aquecimento e sugere-se que o equilíbrio entre ambas as moléculas seja responsável pela redução da toxicidade da AmB. Os resultados aqui apresentados sugerem que o processo de aquecimento controlado altera a organização estrutural das micelas, resultando na diminuição da toxicidade, na melhoria da estabilidade térmica e na manutenção da atividade.

Tumores do espaço parafaríngeo: experiência de 10 anos do IPO-LFG

Introdução: As neoplasias do espaço parafaríngeo são raras, representando apenas 0,5% dos tumores da cabeça e pescoço. A maioria são benignas, mas uma ampla variedade de patologias benignas e malignas podem ser encontradas neste espaço, o que cria desafios complexos de diagnóstico e tratamento. Objetivo: Descrever e analisar uma série de casos de neoplasias primárias do espaço parafaríngeo tratadas no Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG). Material e métodos: Estudo retrospetivo, com recolha e análise dos dados dos processos clínicos de tumores primários do espaço parafaríngeo, que foram diagnosticados ou referenciados ao IPOLFG entre 1 de Janeiro de 2003 e 31 de Dezembro de 2013. Resultados: Foram incluídos 38 doentes. A idade mediana foi de 52 anos (Âmbito Interquartil: 40-63 anos). Dez (26,3%) doentes eram assintomáticos. O sintoma mais comum à apresentação foi a sensação de corpo estranho orofaríngeo (23,7%) e o achado mais frequente foi um abaulamento orofaríngeo (78,4%). Todos os doentes fizeram exames de imagem pré-operatórios: 94,7% tomografia computorizada e 68,4% ressonância magnética. A citologia aspirativa foi realizada em 39,5%. 31 tumores eram benignos (81,6%), sendo os mais frequentes os adenomas pleomórficos (58,1%). 7 eram malignos (18,4%), com os carcinomas exadenomas pleomórficos (28,6%) e os linfomas (28,6%) sendo os mais comuns. 36 doentes (94,7%) foram submetidos a tratamento cirúrgico primário; os outros 2 doentes (5,3%) receberam tratamento não cirúrgico, com quimioterapia e quimioradioterapia, respectivamente. A abordagem cervical foi a mais utilizada (80%). A mandibulotomia foi necessária em apenas 5,7%. A complicação mais frequente foi a neuropatia de pares cranianos de novo, identificada em 22,2%. Destes, 75% foram sequela da resseção de tumores neurogénicos. Todas as neuropatias que resultaram da resseção de tumores não neurogénicos foram transitórias. O follow-up mediano foi de 6,5 anos. A taxa de recorrência foi de 13,5%. Conclusões: Os tumores do espaço parafaríngeo requerem um elevado índice de suspeição para serem diagnosticados num estadio precoce. A resseção cirúrgica completa é o principal tratamento. A abordagem cirúrgica deve ser selecionada caso a caso, mas a cervical fornece um excelente acesso à maioria dos tumores deste espaço

Hybrid materials for biomedical applications

The increased longevity of humans and the demand for a better quality of life have led to a continuous search for new implant materials. Scientific development coupled with a growing multidisciplinarity between materials science and life sciences has given rise to new approaches such as regenerative medicine and tissue engineering. The search for a material with mechanical properties close to those of human bone produced a new family of hybrid materials that take advantage of the synergy between inorganic silica (SiO4) domains, based on sol-gel bioactive glass compositions, and organic polydimethylsiloxane, PDMS ((CH3)2.SiO2)n, domains. Several studies have shown that hybrid materials based on the system PDMS-SiO2 constitute a promising group of biomaterials with several potential applications from bone tissue regeneration to brain tissue recovery, passing by bioactive coatings and drug delivery systems. The objective of the present work was to prepare hybrid materials for biomedical applications based on the PDMS-SiO2 system and to achieve a better understanding of the relationship among the sol-gel processing conditions, the chemical structures, the microstructure and the macroscopic properties. For that, different characterization techniques were used: Fourier transform infrared spectrometry, liquid and solid state nuclear magnetic resonance techniques, X-ray diffraction, small-angle X-ray scattering, smallangle neutron scattering, surface area analysis by Brunauer–Emmett–Teller method, scanning electron microscopy and transmission electron microscopy. Surface roughness and wettability were analyzed by 3D optical profilometry and by contact angle measurements respectively. Bioactivity was evaluated in vitro by immersion of the materials in Kokubos’s simulated body fluid and posterior surface analysis by different techniques as well as supernatant liquid analysis by inductively coupled plasma spectroscopy. Biocompatibility was assessed using MG63 osteoblastic cells. PDMS-SiO2-CaO materials were first prepared using nitrate as a calcium source. To avoid the presence of nitrate residues in the final product due to its potential toxicity, a heat-treatment step (above 400 °C) is required. In order to enhance the thermal stability of the materials subjected to high temperatures titanium was added to the hybrid system, and a material containing calcium, with no traces of nitrate and the preservation of a significant amount of methyl groups was successfully obtained. The difficulty in eliminating all nitrates from bulk PDMS-SiO2-CaO samples obtained by sol-gel synthesis and subsequent heat-treatment created a new goal which was the search for alternative sources of calcium. New calcium sources were evaluated in order to substitute the nitrate and calcium acetate was chosen due to its good solubility in water. Preparation solgel protocols were tested and homogeneous monolithic samples were obtained. Besides their ability to improve the bioactivity, titanium and zirconium influence the structural and microstructural features of the SiO2-TiO2 and SiO2-ZrO2 binary systems, and also of the PDMS-TiO2 and PDMS-ZrO2 systems. Detailed studies with different sol-gel conditions allowed the understanding of the roles of titanium and zirconium as additives in the PDMS-SiO2 system. It was concluded that titanium and zirconium influence the kinetics of the sol-gel process due to their different alkoxide reactivity leading to hybrid xerogels with dissimilar characteristics and morphologies. Titanium isopropoxide, less reactive than zirconium propoxide, was chosen as source of titanium, used as an additive to the system PDMS-SiO2-CaO. Two different sol-gel preparation routes were followed, using the same base composition and calcium acetate as calcium source. Different microstructures with high hydrophobicit were obtained and both proved to be biocompatible after tested with MG63 osteoblastic cells. Finally, the role of strontium (typically known in bioglasses to promote bone formation and reduce bone resorption) was studied in the PDMS-SiO2-CaOTiO2 hybrid system. A biocompatible material, tested with MG63 osteoblastic cells, was obtained with the ability to release strontium within the values reported as suitable for bone tissue regeneration.

Síndrome Takotsubo após procedimento anestésico em idade pediátrica - um caso clínico

A síndrome Takotsubo (STT) é uma forma adquirida e transitória de disfunção sistólica, cuja apresentação clínica e eletrocardiográfica mimetiza um enfarte agudo do miocárdio. A STT é também conhecida como miocardiopatia de stress, síndrome do «coração partido», balonamento apical, insuficiência cardíaca aguda reversível, miocárdio «atordoado» (forma neurogénica) ou miocardiopatia aguda das catecolaminas. Os autores descrevem uma apresentação rara de STT após procedimento anestésico. Adolescente de 14 anos, sexo feminino, com antecedentes pessoais de enxaqueca hemiplé- gica e quisto pineal, submetida a ressonância magnética (RM) cranioencefálica de controlo. Durante a indução anestésica com propofol verificou-se bradicardia, revertida com atropina, seguida de taquidisritmia ventricular, revertida com lidocaína e murro pré-cordial. Nas primeiras horas de internamento evoluiu para edema pulmonar associado a insuficiência respiratória global por disfunção ventricular esquerda aguda. O ecocardiograma transtorácico mostrou dilatação do ventrículo esquerdo com hipocinesia global e fração de ejeção reduzida (< 30%). O eletrocardiograma revelou taquicardia sinusal persistente e alterações inespecíficas do segmento ST. Os biomarcadores cardíacos encontravam-se elevados (troponina 2,42 ng/ml, proBNP 8248 pg/ml). Foi medicada com diuréticos, IECA, digitálico e dopamina, com melhoria clínica, bioquímica e ecocardiográfica ao quarto dia. Os ecocardiogramas subsequentes mostraram normalização da função ventricular. A doente teve alta medicada com carvedilol, que suspendeu após normalização da função cardíaca e RM cardíaca não ter revelado alterações. Estão descritos poucos casos de STT em idade pediátrica. Alguns são desencadeados por patologia aguda do sistema nervoso central, mas nem todos cumprem os critérios de diagnóstico clássicos. Neste caso, o procedimento anestésico poderá ter desencadeado a STT.