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Base de dados : LILACS
Pesquisa : D01.552 [Categoria DeCS]
Referências encontradas : 223 [refinar]
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Id: lil-282681
Autor: Farfalli, Luis.
Título: Artroplastias condilares totales de rodilla con componentes tibiales de base metalica / Tibial component with metalic base in total condylar arthroplasty
Fonte: Rev. Asoc. Argent. Ortop. Traumatol;50(4):381-91, 1985. ilus.
Idioma: es.
Resumo: La observacion de deformacion plastica progresiva con aflojamiento mecanico del componente tibial de polietileno en una artroplastia total condilar, origino la experimentacion con componentes similares pero montados sobre una base metalica de acero inoxidable. En bancos de prueba, estos implantes mostraron una resistencia a las cargas superior al 50 por ciento en relacion a los convencionales totalmente de polietileno. El montaje del platillo de polietileno sobre una base metalica evitaria la deformacion secundaria del plastico, creando una mas uniforme distribucion de las cargas en el extremo proximal de la tibia. Estas caracteristicas determinarian condiciones biomecanicas mas favorables en la interfase cemento-hueso, previniendo los aflojamientos mecanicos. La experiencia clinica se llevo a cabo implantando los componentes de base metalica del sistema total condilar en 18 artroplastias de rodilla realizadas en 17 pacientes adultos de ambos sexos padeciendo osteoartritis y artritis reumatoidea (resumen truncado)
Descritores: Polietilenos
Artrite Reumatoide/cirurgia
Osteoartrite do Joelho/cirurgia
Metais
Prótese do Joelho
-Argentina
Limites: Masculino
Feminino
Responsável: AR337.1 - Biblioteca A.A.O.T.


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Id: biblio-1381930
Autor: Oliveira, Lara Luiza Freitas de; Santos, Hélio Batista dos; Thomé, Ralph Gruppi; Chequer, Farah Maria Drumond.
Título: Efeitos tóxicos à saúde humana e ao ambiente causados pelo derramamento de rejeitos de minério da barragem de Fundão / Toxic effects to human health and the environment caused by the spillage of ore tailings from the Fundão dam
Fonte: J. Health Biol. Sci. (Online);9(1):1-17, 2021. tab, graf.
Idioma: pt.
Resumo: Objetivo: analisar as evidências científicas existentes até o presente momento que descrevem os efeitos tóxicos causados à saúde humana e ao ambiente, devido à liberação dos rejeitos de minério, decorrentes do rompimento da barragem de Fundão em Mariana - MG. Métodos: a revisão narrativa da literatura baseou-se na busca de artigos em quatro bases de dados: PubMed, SciELO, Science Direct e LILACS, utilizando os descritores "Dam", "Fundão" e "Mariana" junto com o operador booleano "AND". Resultados: trinta e quatro das oitenta e cinco publicações encontradas atenderam aos critérios de inclusão e foram utilizadas para compor a presente revisão. Foram observados os seguintes efeitos tóxicos: contaminação da água e do solo, principalmente, por metais pesados, potencial genotóxico, citotóxico e mutagênico da água, diminuição da diversidade microbiana, contaminação de peixes, perda da vegetação e prejuízos ao metabolismo de crescimento de plantas. Entre esses metais, foi relatado aumento na concentração de ferro, manganês, cobre, cádmio, chumbo, arsênio, cromo, magnésio, alumínio, mercúrio, cobalto, bário, níquel e selênio. Além disso, o desastre promoveu o aumento no número de casos de doenças humanas, como dengue, doenças respiratórias, dermatológicas, intestinais, psicológicas e comportamentais. Conclusão: todas as evidências científicas expostas na presente revisão sugerem que houve a contaminação ambiental, bem como da população local, por agentes tóxicos presentes nos rejeitos de minério, em especial metais pesados, liberados após o rompimento da barragem de Fundão. Assim, torna-se essencial a realização de mais estudos que visem esclarecer os efeitos tóxicos crônicos decorrentes dos rejeitos de minério liberados ao ambiente.

Objective: to analyze the scientific evidence existing to date that describes the toxic effects caused to human and the environmental health, due to the release of ore tailings, resulting from the rupture of the Fundão dam in Mariana-MG. Methods: the narrative literature review was based on a search for articles in four databases: PubMed, SciELO, Science Direct and LILACS, using the descriptors "Dam", "Fundão" and "Mariana" together with the Boolean operator "AND". Results: thirty-four, of the eighty-five publications found, met the inclusion criteria and were used to compose the present review. The following toxic effects were observed: contamination of water and soil mainly by heavy metals, genotoxic, cytotoxic and mutagenic potential of water, decrease in microbial diversity, contamination of fish, loss of vegetation, and impairment of plant growth metabolism. Among these metals, increased concentrations of iron, manganese, copper, cadmium, lead, arsenic, chromium, magnesium, aluminum, mercury, cobalt, barium, nickel and selenium were reported. In addition, the disaster promoted an increase in the number of cases of human diseases, such as dengue, respiratory, dermatological, intestinal, psychological and behavioral diseases. Conclusion: all the scientific evidence exposed in the present review that there was environmental contamination, as well as of the local population, by toxic agents present in the ore tailings, especially heavy metals, released after the collapse of the Fundão dam. Thus, further studies aimed at clarifying the chronic toxic effects resulting from the ore tailings released into the environment are essential.
Descritores: Resíduos
Toxicidade
-Poluição da Água
Barragens
Saúde Ambiental
Substâncias Tóxicas
Metais Pesados
Poluição Ambiental
Colapso Estrutural
Metais
Tipo de Publ: Revisão
Responsável: BR1780.2


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Id: lil-647649
Autor: Navarro Genta, Mario; Tagle, A; Montes, Jorge.
Título: Experiencia inicial con el uso de stent metálico resonance ® en el tratamiento de la obstrucción ureteral por causa neoplásica / Initial experience with resonance ® metal stent in the treatment of neoplasic ureteral obstruction
Fonte: Rev. chil. urol;76(1):35-40, 2011. ilus.
Idioma: es.
Resumo: Introducción: La obstrucción ureteral extrínseca provoca un daño de grado variable en la unidad renal comprometida. La hidroureteronefrosis (HUN) que se produce, se trata tradicionalmente en forma inicial, con cateterismo ureteral mediante el uso de stents plásticos que requieren recambio continuamente. Sin embargo, la tasa de éxito disminuye en el tiempo, sumándose mayores probabilidades de complicaciones e infecciones por lo que se requiere generalmente de una nefrostomía definitiva, con la consiguiente alteración en la calidad de vida de estos pacientes. Por esta razón, surge interesante la posibilidad de disponer de un stent ureteral metálico más resistente a la compresión, tolerable y mas durable en el tiempo, y que requiera de una menor tasa de recambio y complicaciones. En esta comunicación Presentamos la primera experiencia del país con el uso del Catéter ureteral metálico Resonance® (Cook Ireland. Ltd.), compuesto de una aleación no magnética de cobalto, níquel, molibdeno y cromo. Se describe la técnica de instalación y los resultados funcionales en una serie consecutiva de 2 pacientes femeninas con seguimiento estricto cada 2 meses. Pacientes y Método:2 pacientes, 42 y 55 años de edad, portadoras de cáncer cérvico uterino tratadas previamente con cirugía, luego radioterapia y braquiterapia, desarrollaron una HUN derecha con atrofia renal contralateral y alteración de la función renal secundaria a compresión extrínseca por reactividad tumoral y fibrosisactínica respectivamente. Se instalaron sendos catéteres Resonance® a derecha en noviembre de2008 y enero de 2009 respectivamente. Se describe la técnica quirúrgica, mejoría de función renal e índice de satisfacción (escala 0 a 10) durante el seguimiento. Resultados: El procedimiento se realizó bajo anestesia regional y radioscopia. Tiempo promedio de 36 minutos (26-46). Período de hospitalización de 1,5 días (1-2). No hubo complicaciones intraoperatorias ni síntomas disúricos...

Introduction: Extrinsic ureteral obstruction leads to damage of varying degrees in the renal unit involved.The hydroureteronephrosis (HUN) is traditionally treated with ureteral catheterization using plastic stents that require continuous replacement. However, the success rate decreases over time, adding greater chance of complications and infections that usually required a definitive nephrostomy, resulting in impaired quality of life of these patients. For this reason, there arises an interesting possibility of having a metallic ureteral stent more resistant to compression, tolerable and more durable over time, and that requires a lower turnover rate and complications. We present the first experience of the country with the use of Resonance® MetallicUreteral catheter (Cook Ireland. Ltd.), consisting of a non-magnetic alloy of cobalt, nickel, molybdenum and chromium. It describes the installation technique and functional outcome in a consecutive series of 2 female patients with close monitoring every 2 months. Patients and methods: Two patients, 42 and 55 years old, carrying cervical cancer previously treated with surgery, radiotherapy and brachytherapy developed a right HUN with contralateral renal atrophy and impaired renal function secondary to extrinsic compression by tumor reactivity and actinic fibrosis respectively. Two separate Resonance® catheters were installed to right in November 2008 and January 2009 respectively. We describe the surgical technique, improved renal function and index of satisfaction (scale of 0 to 10) during follow-up Results: The procedure was performed under regional anesthesia and fluoroscopy. Average time of 36 minutes (26-46). hospitalization time of 1.5 days (1-2). There were no intraoperative or immediate dysuria symptoms. During checks of renal function was normal, no evidence of bleeding or urinary tract infections, reporting a high rate of satisfaction (8 - 9/10). The ultrasound showed a decrease...
Descritores: Cateteres
Neoplasias do Colo do Útero/complicações
Obstrução Uretral/cirurgia
Obstrução Uretral/etiologia
Stents
-Metais
Limites: Humanos
Feminino
Adulto
Pessoa de Meia-Idade
Responsável: CL10.1 - Biblioteca Biomédica


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Texto completo SciELO Costa Rica
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Id: lil-657845
Autor: Lizano, Omar G; Alfaro, Eric J; Salazar Matarrita, Alfonso.
Título: Un método para evaluar el enriquecimiento de metales en sedimentos marinos en Costa Rica / A method to evaluate metal enrichment in marine sediments
Fonte: Rev. biol. trop;60(supl.2):197-211, abr. 2012. graf, mapas, tab.
Idioma: es.
Resumo: A method to evaluate metal enrichment in marine sediments. In order to evaluate metal enrichment in sediments , a method is proposed and tested in Bahia Culebra and the Golfo de Nicoya, Costa Rica through the normalization of the elements against aluminum, and by linear regression of the logarithm of the concentrations of different elements respect to aluminum. The distributions of the elements manganese, and strontium of Bahía Culebra did not satisfy the tests of normalization and linear regression, indicating a nonnatural distribution or enrichment of these elements in this region. In the Golfo de Nicoya the elements copper , zinc , rubidium and the strontium did not satisfy the test of normality or the linear regression with respect to aluminum, indicating a possible enrichment of these elements. The majority of the concentrations of the elements in two sample sites, with the exception of chromium, are within the natural ranges in rocks or clays of marine sediments, and within the concentration ranges of other studies done in these same regions. Chromium has average values beyond the natural concentrations, the values of some samples in the Golfo de Nicoya are up to 10 times greater than the concentration value of a typical bay with high contamination of this element.

Se propone un método para evaluar enriquecimiento de metales en sedimentos de Bahía Culebra y en el Golfo de Nicoya de Costa Rica a través de la normalización de los elementos y el aluminio usando la regresión lineal de las concentraciones de los elementos y el Aluminio. Las distribuciones de los elementos manganeso y el estroncio de Bahía Culebra no cumplen con las pruebas de normalización y de regresión lineal, indicando una distribución no natural o enriquecimiento de estos elementos en esta región. En el Golfo de Nicoya los elementos cobre, zinc, rubidio y el estroncio no cumplen ya sea con la hipótesis de normalidad o con la regresión lineal respecto al aluminio, indicando un posible enriquecimiento de estos elementos en esta región. La mayoría de las concentraciones de los elementos tanto en ambos sitios de muestreo, con excepción del cromo, se encuentran dentro de los ámbitos naturales encontrados en las rocas o en las arcillas de sedimentos marinos a nivel mundial, y dentro de los ámbitos de las concentraciones de otros estudios realizados en estas mismas regiones. El cromo muestra valores promedio más allá de las concentraciones naturales, siendo la concentración de algunas muestras en el Golfo de Nicoya hasta diez veces mayores que el valor de una bahía con alta contaminación de este elemento.
Descritores: Recursos Marinhos
Sedimentos Geológicos/análise
Metais Leves/análise
Metais/análise
-Costa Rica
Poluição Ambiental
Alumínio/análise
Tipo de Publ: Estudo Comparativo
Responsável: CR1.1 - BINASSS - Biblioteca Nacional de Salud y Seguridad Social


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Id: biblio-1378151
Autor: Suárez, Cristina; Forero, Alejandra; Monsalvo, Daniel; Taborda, Alejandra; Londoño, Dario.
Título: Evaluación costo-efectividad de las prótesis con superficie cerámica-polietileno vs. metal-polietileno para reemplazo articular primario de cadera en Colombia / Cost-Effectiveness of Ceramic-Polyethylene Vs Metal-Polyethylene Bearing for Primary Total Hip Replacement in Colombia
Fonte: Rev. colomb. ortop. traumatol;34(3):223-230, 2020. ilus..
Idioma: es.
Resumo: Introducción Existe una diferencia estadísticamente significativa del 1.2% en la tasa de revisión a 15 años a favor de cerámica- polietileno altamente entrecruzado (CP), demostrada en el registro nacional de artroplastia australiano. Nuestro objetivo es evaluar la costo-efectividad entre los pares: cerámica-polietileno altamente entrecruzado (CP) y metal- polietileno altamente entrecruzado (MP) para el pagador en Colombia. Materiales y métodos Se construyó un árbol de decisiones TreeAge Pro® comparando CP vs MP desde la perspectiva del Sistema de Salud Colombiano (SSC). Los parámetros se tomaron de la mejor evidencia disponible, para la efectividad se realizó una revisión sistemática de la literatura y para los costos se usaron tarifas del mercado local. Se determinó la relación de costo-efectividad incremental, asumiendo un horizonte temporal de 15 años y aplicando una tasa de descuento del 5% para costos y efectividad. La incertidumbre fue controlada por un análisis de sensibilidad determinístico y probabilístico. Resultados Para el SSC, con un umbral de 1 PIB per cápita por año de vida ganado ajustado por calidad (AVAC), en adultos llevados a RTC el uso de CP no es costo-efectiva, dado que la efectividad es similar (MP:11,32 AVAC vs CP: 11,36 AVAC) y el costo es tres veces mayor (MP $ 861.826 COP vs CP $ 2.298.090 COP). El análisis de sensibilidad determinístico demuestra que la variable más importante en el resultado es el costo de la cerámica. Discusión Para el SSC el uso rutinario de cabezas de cerámica en RTC no es una estrategia costo-efectiva.

Background There is a statistically significant difference of 1.2% in the revision rate in a 15 year follow in favour of the use of ceramic on highly cross-linked polyethylene (CP) recently described in the Australian National Joint Registry. The purpose of this study is to compare the cost-effectiveness of CP implants and metal-on-highly cross-linked polyethylene (MP) implants in patients undergoing total hip replacement (THR). Materials and methods A TreeAge Pro® decision tree was constructed in order to determine cost-effectiveness between two bearing surfaces: CP or MP from the perspective of the Colombian Health Care System (CHCS). The model parameters where taken from the best available evidence. For the effectiveness, a systematic review of the literature was performed, and costs were taken from local market rates. The incremental cost-effectiveness ratio was determined assuming a time horizon of 15 years, and a discount rate of 5% was used for costs and effectiveness. Cost-effectiveness uncertainty was controlled with deterministic and probabilistic sensitivity analysis. Results For the CHCS, with a 1PIB per capita threshold adjusted per QALY in adults undergoing (THR), the use of a CP implant is not cost-effective, given that the effectiveness is similar (11.32 QALY for MP vs 11.36 QALY for CP), and the cost is three times higher (MP $ 861.826 COP vs CP $ 2.298.090 COP). The deterministic sensitivity analysis showed that the most important variable in the results is the ceramic cost. Discussion for the CHCS the routine use of ceramic-highly cross-linked polyethylene bearing surface in a THR is not a cost-effective strategy.
Descritores: Artroplastia de Quadril
Polietileno
-Cerâmica
Análise Custo-Benefício
Metais
Limites: Humanos
Responsável: CO5.1 - Centro de Información y Conocimiento


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Texto completo SciELO Chile
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Id: lil-745577
Autor: Wei, Kelvin Swee Chuan; Teoh, Teow Chong; Koshy, Philip; Salmah, Ismail; Zainudin, Arifin.
Título: Cloning, expression and characterization of the endoglucanase gene from Bacillus subtilis UMC7 isolated from the gut of the indigenous termite Macrotermes malaccensis in Escherichia coli
Fonte: Electron. j. biotechnol;18(2):103-109, Mar. 2015. ilus, graf, tab.
Idioma: en.
Projeto: University of Malaya.
Resumo: Background Bacillus subtilis UMC7 isolated from the gut of termite Macrotermes malaccensis has the ability to secrete a significant amount of extracellular endoglucanase, with an enzyme activity of 0.12 ± 0.01 μmol/min/mL. However, for economically viable industrial applications, the enzyme needs to be expressed in a heterologous host to overcome the low enzyme production from the wild-type strain. Results The endoglucanase gene from B. subtilis UMC7 was successfully cloned and expressed. A higher enzyme activity was observed in the intracellular fraction of the recombinant clone (0.51 ± 0.02 μmol/min/mL) compared with the cell-bound fraction (0.37 ± 0.02 μmol/min/mL) and the extracellular fraction (0.33 ± 0.01 μmol/min/mL). The recombinant endoglucanase was approximately 56 kDa, with optimal enzyme activity at 60°C and pH 6.0. The activity of the enzyme was enhanced by the addition of Ca2 +. However, the enzyme was inhibited by other metal ions in the following order: Fe3 + > Ni2 + > Cu2 + > Mn2 + = Zn2 + > Mg2 + > Cd2 + > Cr2 +. The enzyme was able to hydrolyze both low- and high-viscosity carboxymethyl-cellulose (CMC), avicel, cotton linter, filter paper and avicel but not starch, xylan, chitin, pectin and p-nitrophenyl α-d-glucopyranoside. Conclusions The recombinant endoglucanase showed a threefold increase in extracellular enzyme activity compared with the wild-type strain. This result revealed the potential of endoglucanase expression in E. coli, which can be induced for the overexpression of the enzyme. The enzyme has a broad range of activity with high specificity toward cellulose.
Descritores: Bacillus subtilis/enzimologia
Celulase/genética
Celulase/metabolismo
Isópteros
-Especificidade por Substrato
Temperatura
Bacillus subtilis/isolamento & purificação
Proteínas Recombinantes
Amplificação de Genes
Clonagem Molecular
Análise de Sequência
Escherichia coli
Concentração de Íons de Hidrogênio
Intestinos/microbiologia
Íons
Metais
Responsável: CL1.1 - Biblioteca Central


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Id: lil-764017
Autor: Liu, Chunming; Zhao, Yixin; Liu, Jianfeng; Gen, Wanting; Cheng, Yunqing.
Título: The effects of ethylene on the HCl-extractability of trace elements during soybean seed germination
Fonte: Electron. j. biotechnol;18(5):333-337, Sept. 2015. ilus, graf, tab.
Idioma: en.
Projeto: National Natural Science Foundation of China.
Resumo: Background Ethylene is capable of promoting seed germination in some plant species. Mobilization of metals such as Fe, Cu, Mn, and Zn in mature seeds takes place when seeds are germinating. However, whether ethylene is involved in the regulation of soybean seed germination and metal element mobilization during early seed germination stage remains unknown. In the present study, seeds were treated with ethylene synthesis inhibitor aminoethoxyvinylglycine (AVG) and ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), and double distilled H2O (ddH(2)0) treatment was used as control. Ethylene emission, ACC synthase (ACS) expression, ACS enzyme activity and Ca, Zn, Mn, Cu and Fe content in hypocotyls were qualified to analyze the relationship between ethylene and mobilization of these elements. Results The results showed that ACS expression, ACS enzyme activity and ethylene emission peaked at 1 and 7 d after sowing. AVG inhibited ethylene production, promoted the hypocotyls length, ACS expression and its activity, concentrations of total and HCl-extractable Zn, and HCl-extractable Fe in hypocotyls, while ACC caused opposite effects. AVG and ACC treatment had no significantly effects on total and HCl-extractable Ca, Cu and HCl-extractable Mn. Total Mn concentration was promoted by AVG at 1, 3, and 5 d significantly, while ACC treatment tended to have no significantly effects on Mn concentration. Conclusion These findings suggested that ethylene is at least partly involved in the regulation of soybean seed germination. Remobilization of Zn and Fe may be negatively regulated by ethylene.
Descritores: Sementes
Soja
Germinação
Etilenos
Liases/metabolismo
Metais/metabolismo
-Zinco/metabolismo
Reação em Cadeia da Polimerase Via Transcriptase Reversa
Ferro/metabolismo
Responsável: CL1.1 - Biblioteca Central


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Id: biblio-1359597
Autor: Jiménez del Río, Marlene.
Título: Modelo molecular unificado de estrés oxidativo en las enfermedades de Alzheimer y Parkinson / Unified molecular model of stress oxidative in diseases Alzheimer's and Parkinson's
Fonte: Salud(i)ciencia (Impresa) = Salud(i)ciencia (En linea);12(6):27-31, 2004. graf..
Idioma: es.
Resumo: Alzheimer's disease (AD) and Parkinson's disease (PD) are the most frequent progressive neurodegenerative diseases affecting millions of people in the world. Because a significant percentage of patients share common clinical and pathological features from both entities, this may indicate the existence of a common pathological mechanism. Based on in vitro and in situ data, authors proposed an unified molecular oxidative stress model induced by dopamine (DA), 6-hydroxydopamine (6-OHDA); 5,6 & 5,7-dihydrytryptamine (5,6 & 5,7 DHT); amyloid beta 25-35 (Aß25-35), and metals [e. g. iron (Fe2+), copper (Cu2+), zinc (Zn2+), manganese (Mn2+)], as a possible explanation of neural loss in AD/PD overlapping cases. This hypothesis might contribute to a better understanding of the pathophysiology cascades of both disorders, and also support the notion that oxidative stress generated by H2O2 represent an essential molecule of intracellular signalization leading to cell death. Taken together, these findings might allow a better rational approach to therapeutic design that rescue, delay or retard cell death in patients suffering from those deteriorating disorders.

La enfermedad de Alzheimer (EA) y la enfermedad de Parkinson (EP) son los trastornos neurodegenerativos progresivos que afectan con mayor frecuencia a millones de personas en el mundo. Dado que un porcentaje significativo de pacientes comparten características clínicas y patológicas de ambas entidades, esto podría indicar la existencia de un mecanismo patológico común. Con base en estudios in vitro e in situ, los autores proponen un modelo molecular unificado de estrés oxidativo en EA y EP, inducido por los estímulos tóxicos, la dopamina (DA), la 6- hidroxidopamina (6-OHDA), la 5,6-dihidroxitriptamina (5,6-DHT), la 5,7-dihidroxitriptamina (5,7-DHT), el beta-amiloide 25-35 (Aß[25-35]) y los metales (v. gr. hierro [Fe2+], cobre [Cu2+], cinc [Zn2+], manganeso [Mn2+]) como posible explicación a la pérdida neuronal en algunos casos mixtos con EA/EP. Esta hipótesis podría contribuir a una mejor comprensión de las cascadas fisiopatológicas en ambos desórdenes y valida la idea de que el estrés oxidativo generado por el peróxido de hidrógeno (H2 O2) representa una molécula fundamental de señalización de muerte celular. En conjunto, estas investigaciones permitirían un mejor acercamiento racional en los diseños terapéuticos que rescaten, detengan o retarden los procesos de deterioro neuronal en los pacientes que padecen estas devastadoras patologías.
Descritores: Doença de Parkinson
5,6-Di-Hidroxitriptamina
5,7-Di-Hidroxitriptamina
Doença de Alzheimer
-Dopamina
Oxidopamina
Morte Celular
Cobre
Amiloide
Metais
Limites: Humanos
Responsável: AR392.1 - Biblioteca


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Texto completo SciELO Costa Rica
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Id: biblio-958215
Autor: Vargas, José-A; Acuña-González, Jenaro; Vásquez, Fiorella; Sibaja-Cordero, Jeffrey-A.
Título: Brachiopods, sipunculans, enteropneusts and metals from two estuarine tidal flats, Pacific, Costa Rica / Braquiópodos, sipuncúlidos, enteropneustos y metales en dos planicies estuarinas de marea, Pacífico, Costa Rica
Fonte: Rev. biol. trop;64(3):1311-1331, jul.-sep. 2016. tab, ilus.
Idioma: en.
Resumo: Abstract:Reports on the abundances and on metal concentrations in intertidal estuarine invertebrates from the Eastern Tropical Pacific are rare. Thus, the objectives of this report are to make accessible data on the abundances (1984-1987, 49 dates; 2013, 12 dates) of sipunculans, brachiopods and hemichordates from a sand-mud flat; and on trace metals (1996, 2000) and abundances (2015, 3 dates) of sipunculans and brachiopods at a sand flat in the Gulf of Nicoya estuary (10o N-85o W). Cores (17.7 cm2) were collected at the sand-mud flat, and quadrats (0.2 m2) at the sand flat. The flats contrasted in their sand (65 % vs 90 %) and silt+clay (31.5 % vs 5.6 %) contents. At the sand-mud flat (1984-87: 1.83 m2) the sipunculans were represented by 13 individuals, the brachiopods by 129 and the acorn worms by 185, with estimated maximum densities of: 5.7, 29, and 40 ind./m2, respectively. Trace metal (Fe, Mn, Ni, Cr, Cd, Zn, and Pb) analysis (Atomic Absorption Spectrometry) were conducted in specimens of Sipunculus nudus (Sipuncula) and Glottidia audebarti (Brachiopoda). Maximum mean concentrations in S. nudus were: For non-depurated worms, Fe (16.0 mg/g dw) > Mn (165 µg/g dw) > Zn (81 µg/g dw) > Cu (26 µg/g dw) > Cr (11 µg/g dw) > Ni (10.4 µg/g dw) > Pb (9.3 µg/g dw) > Cd (1.2 µg/g dw). For 72 hour depurated worms: Fe (5.0 mg/g dw) > Mn (61 µg/g dw) > Zn (39 µg/g dw) > Cu (24 µg/g dw) > Ni (8.4 µg/g dw) > Pb (2.7 µg/g dw) > Cd (0.62 µg/g dw). For G. audebarti: Fe (1.6 mg/g dw-soft parts) > Zn (123.5 µg/g dw-soft parts) > Cu (31.4 µg/g dw-pedicles) > Pb (21.0 µg/g dw-shells) > Cd (5.2 µg/g dw-soft parts) > Cr (4.7 µg/g dw-shells). For sediments; Fe (46 mg/g dw) > Mn (41.3 µg/g dw) > Zn (63 µg/g dw) > Cu (36.2 µg/g dw) > Cr (31.5 µg/g dw) > Pb (21.1 µg/g dw) > Ni (16.1 µg/g dw) > Cd (1.1 µg/g dw). These concentrations were expected for a nonindustrialized estuary. At the sand flat (Area sampled: 10.6 m2 ) 76 individuals of G. audebarti, 112 of G. albida, and 366 of S. nudus were collected in 2015, with estimated maximum densities of: 7.1, 10.5, and 31 ind./m2, respectively. Densities of G. audebarti and G. albida were relatively low, while those of S. nudus were relatively high when compared with other reports. The shell lenght of G. audebarti ranged from 9.0 mm to 38.0 mm and from 6.0 mm to 29.0 mm for G. albida. These ranges were within those found for these lingulides elsewhere. The mean length of S. nudus was 41 mm and the maximum weight was 1.6 g, which are small. No brachiopods were found at the sand-mud flat in 2013, nor enteropneusts at the sand flat in 2015. G. audebarti had a relatively stable presence, while G. albida almost vanished from the samples at the end of 2015. The spatial distributions of the three invertebrates were found aggregated at both intertidal flats. Strong ENSO warming events during 1983 and 2015, and red tides in 1985 may have influenced the abundances. Rev. Biol. Trop. 64 (3): 1311-1331. Epub 2016 September 01.

ResumenSon raros los reportes sobre las abundancias y concentraciones de metales en invertebrados estuarinos de la zona de entre-mareas del Pacífico Este Tropical. Los objetivos de este informe son el hacer accesibles datos sobre las abundancias (1984-1987, 49 fechas; 2013, 12 fechas) de sipuncúlidos, braquiópodos y hemicordados en una planicie arenoso-fangosa y sobre metales traza (1996, 2000) y abundancias (2015, 3 fechas) de sipuncúlidos y braquiópodos en una planicie arenosa en el estuario del Golfo de Nicoya (10o N-85o W). Barrenos (17.7 cm2) fueron recolectados en la planicie arenoso-fangosa y cuadrantes (0.2 m2) en la arenosa. Las planicies contrastaron en sus contenidos de arena (65 % vs 90 %) y de limo + arcilla (31.5 % vs 5.6 %). En la planicie arenoso-fangosa (1984-87: 1.83 m2) los sipuncúlidos estuvieron representados por 13 individuos, los braquiópodos por 129 y los hemicordados enteropneustos por 185, con densidades estimadas de: 5.7, 29, y 40 ind. /m2, respectivamente. Análisis de metales traza (Fe, Mn, Ni, Cr, Cd, Zn, y Pb) por Espectrometría de Absorción Atómica (AAS) fueron hechos en especímenes de Sipunculus nudus (Sipuncula) y Glottidia audebarti (Brachiopoda). Concentraciones máximas promedio en S. nudus fueron: para gusanos no-depurados, Fe (16.0 mg/g dw) > Mn (165 µg/g dw) > Zn (81 µg/g dw) > Cu (26 µg/g dw) > Cr (11 µg/g dw) > Ni (10.4 µg/g dw) > Pb (9.3 µg/g dw) > Cd (1.2 µg/g dw). Para gusanos depurados por 72 horas: Fe (5.0 mg/g dw) > Mn (61 µg/g dw) > Zn (39 µg/g dw) > Cu (24 µg/g dw) > Ni (8.4 µg/g dw) > Pb (2.7 µg/g dw) > Cd (0.62 µg/g dw). Para G. audebarti: Fe (1.6 mg/g dw-partes suaves) > Zn (123.5 µg/g dw-partes suaves) > Cu (31.4 µg/g dwpedículos) > Pb (21.0 µg/g dw-conchas) > Cd (5.2 µg/g dw-partes suaves) > Cr (4.7 µg/g dw-conchas). Para sedimentos; Fe (46 mg/g dw) > Mn (41.3 µg/g dw) > Zn (63 µg/g dw) > Cu (36.2 µg/g dw) > Cr (31.5 µg/g dw) > Pb (21.1 µg/g dw) > Ni (16.1 µg/g dw) > Cd (1.1 µg/g dw). Estas concentraciones fueron esperables para un estuario no industrializado. En la planicie arenosa (Area muestreada: 10.6 m2) 76 individuos de G. audebarti, 112 de G. albida y 366 de S. nudus fueron recolectados en el 2015, con densidades estimadas de: 7.1, 10.5, y 31 ind. /m2, respectivamente. Densidades de G. audebarti y G. albida fueron relativamente bajas, mientras que las de S. nudus fueron relativamente altas cuando se les comparó con otros reportes. La longitud de la concha de G. audebarti varió entre 9.0 mm y 38.0 mm y entre 6.0 mm a 29.0 mm la de G. albida. Estos ámbitos estuvieron dentro de los encontrados para estos lingúlidos en otros sitios. La longitud promedio de S. nudus fue 41 mm y el peso máximo fue de 1.6 g que son pequeños. En la planicie arenoso-fangosa no se encontró braquiópodos en el 2013, ni enteropneustos en la planicie arenosa en el 2015. G. audebarti tuvo una presencia relativamente estable, mientras que G. albida casi desapareció de las muestras al final del 2015. La distribución espacial de las tres especies fue de tipo agregado en ambas planicies. Fuertes eventos ENSO durante 1983 y 2015, así como mareas rojas en 1985, pueden haber influenciado las abundancias.
Descritores: Cordados não Vertebrados/fisiologia
Estuários
Invertebrados/fisiologia
Metais/análise
Nematoides/fisiologia
-Valores de Referência
Estações do Ano
Água do Mar/química
Especificidade da Espécie
Espectrofotometria Atômica
Poluentes Químicos da Água/análise
Oceano Pacífico
Monitoramento Ambiental/métodos
Densidade Demográfica
Sedimentos Geológicos
Costa Rica
Análise Espaço-Temporal
Distribuição Animal
Limites: Animais
Responsável: BR1.1 - BIREME


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Id: biblio-951541
Autor: Department of Prosthodontics and PeriodonticsCaldas, Ricardo Armini; Pfeifer, Carmem Silvia Costa; Department of ProsthodonticsBacchi, Ataís; Department of RestorativeSantos, Mateus Bertolini Fernandes dos; Department of Prosthodontics and PeriodonticsReginato, Vagner Flávio; Department of Prosthodontics and PeriodonticsConsani, Rafael Leonardo Xediek.
Título: Implant inclination and horizontal misfit in metallic bar framework of overdentures: analysis by 3d-fea method
Fonte: Braz. dent. j;29(2):166-172, Mar.-Apr. 2018. tab, graf.
Idioma: en.
Resumo: Abstract The aim of this study was to evaluate by three-dimensional finite element analysis (3D-FEA) the biomechanics involved in bar-framework system for overdentures. The studied factors were latero-lateral angulation in the right implant (-10, -5, 0, 5 and 10 degrees), and different bar cross-sections (circular, Hader and oval) presenting horizontal misfits (50 or 150 µm) on the opposite implant. Positive angulation (5 and 10 degrees) for implant inclination to mesial position, negative angulation (-5 and -10 degrees) for distal position, and zero degree for parallel implants. The von Mises stresses evaluated the bar, screw and the implant; maximum principal, minimum principal and shear stress analyses evaluated the peri-implant bone tissue. Parallel implants provide lower stress in alveolar bone tissue; mesial inclined bars showed the most negative effect on prosthetic structures and implants. In conclusion, bar cross-section showed no influence on stress distribution for peri-implant bone tissue, and circular bar provided better behavior to the prosthetic system. Higher stress concentration is provided to all system as the misfit increases.

Resumo O objetivo neste estudo foi avaliar por meio do método por elemento finito tridimensional (3D-AEF) a biomecânica envolvida na infraestrutura do sistema barra-clipe para overdentures. Os fatores de estudo foram inclinação mésio-distal entre implantes (-10, -5, 0, 5, 10 graus) e diferentes seções transversais da barra metálica (circular, oval e Hader) com desajuste horizontal (50 e 150 µm). Valores de inclinação positivas (5 e 10 graus) indicam inclinação do implante para mesial e valores negativos (-5 e -10 graus) mostram inclinação para distal, enquanto zero grau indica implantes paralelos. Valores de tensões equivalentes de von Mises foram utilizadas nos sistemas barra, parafuso e implante. Tensão máxima e mínima principal, e cisalhante foram utilizadas para análise do osso alveolar peri-implante. Implantes paralelos promoveram menores tensões em tecido peri-implante; as inclinações para mesial apresentaram piores resultados para as estruturas protéticas e implantes. As diferentes seções transversais da barra não mostraram influência na distribuição de tensões no osso alveolar peri-implante. Concluindo, a barra circular apresentou melhores resultados para os componentes protéticos e maiores valores de tensões foram observados em todos os modelos na medida que o desajuste aumentou.
Descritores: Implantes Dentários
Revestimento de Dentadura
Metais/química
-Fenômenos Biomecânicos
Retenção de Dentadura
Análise de Elementos Finitos
Análise do Estresse Dentário/métodos
Limites: Humanos
Responsável: BR1.1 - BIREME



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