This research presents some geochemical aspects of the marine surface sediments of the north coast of the Gulfof Cariaco, in the state of Sucre, Venezuela. The gulf has a tectonic structure and a fault system mainly featuring sandysediments, most of which are quite permeable and have an average hydric content of 22.44%. The content of organic matterdetected was low, averaging 7.63%, organic carbon and calcium carbonate commanding 0.97% and 21.97%, respectively.Contrarily, phosphorus and total nitrogen were high, 360.03 mg.g-1 for the former and 396.29 mg.g-1 for the latter, the totalnitrogen to phosphorus ratio being 1.09, which indicates a certain degree of organic fertility. The metal concentrationspresented different distributions, averaging 3548.58, 14.63, 13.68, 11.59, 10.23, 2.29, 1.04, and 0.57 mg.g-1 for iron,manganese, nickel, zinc, chromium, copper, cadmium, and lead, respectively, indicative of contamination, especially bycadmium. The nonlinearity with the iron presented by some metals such as copper, nickel, and manganese suggests theexistence of anthropogenic influxes, probably swayed by river-borne industrial contributions, including the exogenous dischargesrunning seawards from the south coast.

Se realizo la caracterizacion geoquimica sedimentos superficiales de cano Manamo en el delta del rio Orinoco. Las muestras de sedimento analizadas corresponden a 7 estaciones establecidas a todo lo largo del cano, muestreandose en cada estacion ambas margenes y la zona central del rio. El analisis textural de los sedimentos se llevo a cabo mediante el metodo sedimentologico de Bouyoucos, la materia organica por termogravimetria y el carbono organico mediante digestion humeda. Los sedimentos pulverizados fueron sometidos a fraccionamiento con acidos debiles y fuertes para separar los metales asociados a la fraccion biodisponible (extraidos con acido acetico al 10%) y residuales (extraidos con mezcla de acido nitrico y peroxido de hidrogeno). La cuantificacion de los metales se realizo por espectrometria de emision atomica con plasma acoplado inductivamente (ICP-EOS). La concentracion de aceites y grasas e hidrocarburos se determino por el metodo CARIPOL y el metodo 8440 de la US EPA. Los sedimentos superficiales del cano Manamo se clasifican como del tipo arenoso y areno limosos, con un promedio de 65,66% de arena, 21,84% de limo y 11,93% de arcilla. El contenido materia organica fluctuo entre 0,12 a 14,92% y un valor promedio de 2,54%. La maxima concentracion de materia organica se determino en una de las margenes del sector de Winamorena. El resto de las estaciones presentaron valores inferiores al 5%. Las concentraciones de carbonatos variaron 0,14-2,51%, con un promedio de 0,62%. Las mayores concentraciones de metales se presentan en la fraccion residual (Fr) asi como en los oxihidroxidos de hierro y manganeso (F3). En el caso de Mn y el Cu se detectaron niveles de metales asociados a las fracciones intercambiables (F1) y carbonatos (F2). No se detectaron los metales Cd, Ni, Co y As en ninguna de las estaciones ni fracciones geoquimicas de los sedimentos superficiales. Se observa una tendencia general donde las mayores concentraciones de aceite y grasas e hidrocarburos alifaticos se presentan hacia la margen con menor influencia del flujo del cano donde se presentan menores contenidos de limos y arcillas. La textura de los sedimentos asi como el contenido de metales y materia organica estan condicionados por la hidrodinamica del cano Manamo y la interaccion con la cuna salina en el tramo cercano a su desembocadura. Existe una fuerte asociacion entre los metales y la materia organica con las fracciones limosas y arcillosas de los sedimentos. Palabras clave: Calidad de sedimentos, fraccionamiento geoquimico, cano Manamo ABSTRACT: The geochemical characterization of surface sediments of cano Manamo in the delta of the Orinoco River, was performed. The sediment samples analyzed correspond to 7 stations established throughout the pipe, both being sampled at each station and the central banks of the river. Textural analysis of sediment was conducted by the sedimentological method of Bouyoucos, organic matter by thermogravimetry and organic carbon by wet digestion. Powdered sediment underwent fractionation with weak and strong acid to remove metals associated to the bioavailable fraction (extracted with 10% acetic acid) and residual (extracted with mixture of nitric acid and hydrogen peroxide). The quantification of metals was performed by atomic emission spectrometry with inductively coupled plasma (ICP-EOS). The concentration of oils and fats and hydrocarbons were determined by the methods of CARIPOL and 8440 U.S. EPA. The surface sediments of cano Manamo are classified as sandy and sandy silt, with an average of 65.66% sand, 21.84% silt and 11.93% clay. The organic matter content ranged from 0.12 to 14.92% and an average value of 2.54%. The highest concentration of organic matter was found in one of the margins Winamorena sector. The remaining stations had values lower than 5%. Carbonate concentrations ranged from 0.14 to 2.51%, with an average of 0.62%. The highest concentrations of metals were identified in the residual fraction (Fr) as well as the iron and manganese oxyhydroxides (F3). In the case of Mn and Cu, metal levels were discovered associated with interchangeable fractions (F1) and carbonates (F2). We detected metals Cd, Ni, Co and As in none of the stations or geochemical fractions of the surface sediments. There is a general trend where the highest concentrations of oil and grease and aliphatic hydrocarbons occur toward the lower margin of the river flow influence which have lower content of silt and clay. The texture of the sediments and metal content and organic matter are conditioned by the hydrodynamics of cano Manamo and interaction with the salt wedge in the stretch near its mouth. There is a strong association between metals and organic matter silt and clay fractions of sediments. Key words: Quality of sediment, geochemical fractionation, cano Manamo.

The content of Fe, Mn, Cu, Cr, Ni, Zn, Cd and Pb in muscle tissuesof fish and crustaceans from the Unare lagoon (Lagunade Unare) in the state of Anzoátegui, Venezuela, was analyzedby flame Atomic Absorption Spectrometry. The levels of thesemetals present in suspended material of the water and in sedimentswere also determined in order to detect possible impacton the ecosystem. The mean concentrations in the water werelow (0.104-0.53 μmol/L Fe; 0.004-0.06 μmol/L Mn; 0.002-0.028μmol/L Zn; 0.004-0.012 μmol/L Cr; undetectable-0.011 μmol/LNi and undectable-0.001 μmol/L Cd). In the sediments, evidencewas found of anthropogenic intervention with mean valuesin decreasing order of Mn (516.37) > Zn (127.49) > Ni(52.41) > Cr (51.69) > Cu (41.13) > Pb (29) > Cd (1.51 μg/g),all of which are greater than established levels for uncontaminatedsediments. Toxic metals were detected in the examinedorganisms, such as lead and cadmium with levels above 0.16and 0.04 μg/g, respectively, and zinc with levels greater than17 μg/g in the majority of the species. ANOVA statistical tests(P < 0.05) show discrepancies in the concentrations or themetals in the tissues of the different genera and species, aswell as in the values for individuals of the same species(Cathorops spixii) which live inside and outside of the lagoon.The levels are higher in those which live within the lagoon, which indicates bioaccumulation processes. This study confirmsthat the lagoon and its biota have suffered a progressiveand important deterioration inasmuch as the neighboring populationrelies on the commercialization of the fish and crustaceansfor their economic stability.

The content of Fe, Mn, Cu, Cr, Ni, Zn, Cd and Pb in muscle tissues of fish and crustaceans from the Unare lagoon (Laguna de Unare) in the state of Anzoategui, Venezuela, was analyzed by flame Atomic Absorption Spectrometry. The levels of these metals present in suspended material of the water and in sediments were also determined in order to detect possible impact on the ecosystem. The mean concentrations in the water were low (0.104-0.53 mu mol/L Fe; 0.004-0.06 mu mol/L Mn; 0.002-0.028 mu mol/L Zn; 0.004-0.012 mu mol/L Cr; undetectable-0.011 mu mol/L Ni and undectable-0.001 mu mol/L Cd). In the sediments, evidence was found of anthropogenic intervention with mean values in decreasing order of Mn (516.37) > Zn (127.49) > Ni (52.41) > Cr (51.69) > Cu (41.13) > Pb (29) > Cd (1.51 mu g/g), all of which are greater than established levels for uncontaminated sediments. Toxic metals were detected in the examined organisms, such as lead and cadmium with levels above 0.16 and 0.04 mu g/g, respectively, and zinc with levels greater than 17 mu g/g in the majority of the species. ANOVA statistical tests (P < 0.05) show discrepancies in the concentrations or the metals in the tissues of the different genera and species, as well as in the values for individuals of the same species (Cathorops spixii) which live inside and outside of the lagoon. The levels are higher in those which live within the lagoon, which indicates bioaccumulation processes. This study confirms that the lagoon and its biota have suffered a progressive and important deterioration inasmuch as the neighboring population relies on the commercialization of the fish and crustaceans for their economic stability.

To detected alterations in the productive ecosystem of the Castillero Lagoon (Caicara of the Orinoco, Cedeno Municipality, Bolivar State, Venezuela), results are presented for granulometric measurements and heavy metals concentrations: Fe, Mn, Zn, Pb and Co made in June 2001 on superface sediments and of the muscular tissue of several native species of fish (Plasgiosium squamossimos, Pigocentrus cariba, Pheudoplastyloma fasciatum, and Hypostomus spp. By using atomic absorption spectrophotometry with an air-acetylene flame, it was determined that the highest concentrations of metals are represented by manganese, zinc and lead. It was determined that the highest concentrations of metals are represented by manganese, zinc and lead. In the most internal part in the lagoon the type of predominant sediments is the mud, constituting among 30% and 65% of the material collected by station. Is that those levels fall toward the mouth of the lagoon, product of the interaction of the flow / reflux currents that washes the sediment and that is reflected in the biggest presence of fine sand. The statistical analysis of ANOVA shows significant differences among the concentrations of the metals in the stations, tipificated for the presence of different averages. The averages levels for the superficial sediments of the area are the following ones: Fe (3365.44+/-261.61), Mn (132.17+/-25.46), Zn (253.04+/-86.48), Pb (17.02+/-2.21) y Co (4.65+/-0.76) mu g/g. In similarly way, in the muscular tissue of the fish the following concentrations were quantified: Fe between (31.26+/-0.06) and (68.36+/-0.05); Mn between (2.02+/-0.05) and (4.1+/-0.03); Zn between (19.09+/-0.01) and (28.89+/-0.01); Pb between (0.38+/-0.01) and (0.47+/-0.03) mu g/g. The analysis reflects a remarkable association between the high securities of concentrations of metals and the sediments type, with a growing gradient toward the sediments type mud. These are alarming values in concentration of Pb and Zn, attributed to the stress that produces the anthropogenic activities surrounding the Lagoon of Castillero. It can be concluded that based on the diagnosis that the ecosystem of the lagoon is in evident state of deterioration with implications that could affect the species inhabit, and the economic activities of the population that exploit the resources biotiques of that body of water.

RESUMEN: Los metales trazas pueden ser acumulados y transformar los nutrientes en sustancias toxicas; por ello, sepropuso determinar las concentraciones (mg Kg-1 de masa seca) de zinc, hierro, manganeso, cobre, cromo, cadmio, plomo yniquel en tejidos blandos de las jaibas Callinectes ornatus, procedentes de las lagunas Bocaripo y Chacopata, en epocas de sequiae inicio de invierno, usando un espectrometro de absorcion atomica Perkin Elmer 3110 con llama de aire-acetileno y correctorde fondo de deuterio. Las concentraciones promedio de los metales no superaron los limites permitidos para consumo animaly humano. Las comparaciones entre lagunas mostraron diferencias significativas para cromo (P=7,97E-6), niquel (P=1,08E-7),zinc (P=2,91E-2) y plomo (P=2,96E-3), lo que indica diferentes condiciones hidro-geoquimicas que los afectan. Los contenidosde metales trazas determinados en C. ornatus procedentes de la laguna Chacopata mostraron correlaciones positivas significativasentre Mn-Zn (r=0,547), Mn-Fe (r=0,496), Cr-Zn (r=0,690), Ni-Zn (r=0,430) y Ni-Cr (r=0,516); mientras que para la lagunaBocaripo fueron Fe-Zn (r=0,473), Mn-Zn (r=0,801), Mn-Fe (r=0,600), Cd-Zn (r=0,569) y Cd-Mn (r=0,545). Por otra parte,las correlaciones entre las concentraciones de los metales trazas en restos de tejidos blandos de C. ornatus y las concentracionesbiodisponibles que han sido referidas en sedimentos superficiales de los mismos lugares de procedencia de los organismosanalizados mostraron para la laguna Chacopata coeficientes de correlacion significativos que explicaron un modelo decorrelacion lineal para manganeso (r=0,533), zinc (r=0,568), niquel (r=0,696) y cromo (r=0,730); no obstante, para la lagunaBocaripo solamente la correlacion lineal del hierro fue explicada por su coeficiente de correlacion (r=0,561), sugiriendo queesos metales llegan desde el sedimento. C. ornatus ingiere sedimentos superficiales desde los cuales absorbe metales biodisponiblescomo manganeso, zinc, niquel, cromo (laguna Chacopata) y hierro (laguna Bocaripo); ademas, pueden acumular plomo, viacadena trofica, y cadmio, desde la solucion. Palabras claves: sustancias toxicas, biodisponibilidad, cangrejos. ABSTRACT: The remnants of the processing of soft tissues of the crab Callinectes ornatus, a very abundant species withinthe Bocaripo and Chacopata lagoons, can be used to make non-traditional fishmeals. However, they can contain levels oftrace metals that could render them non-nutritive or toxic for animal or human consumption. In this regard, this studypurports to determine the variation of trace metals (mg Kg-1 dry weight) in the soft tissues of the crab during the dry and initialrainy seasons. A Perkin Elmer 3110 atomic absorption spectrometer equipped with acetylene flame and deuterium backgroundcorrector was used for the measurements. The average concentrations of metals in the soft tissue of the crab did not surpassthe allowable levels for human or animal consumption. Comparisons between the lagoons showed significant differences forchromium (P=7.97E-6), nickel (P=1.08E-7), zinc (P=2.91E-2), and lead (P=2.96E-3), which suggests that different hydro-geochemical conditions affect them. The trace metal contents in soft tissue of C. ornatus from Chacopata Lagoon showedsignificant positive correlations between Mn-Zn (r=0.547), Mn-Fe (r=0.496), Cr-Zn (r=0.690), Ni-Zn (r=0.430), and Ni-Cr(r=0.516); whereas those from Bocaripo Lagoon were Fe-Zn (r=0.473), Mn-Zn (r=0.801), Mn-Fe (r=0.600), Cd-Zn (r=0.569),and Cd-Mn (r=0.545). On the other hand, the correlations between trace metal concentration in soft tissue remnants of C.ornatus and the bio-available concentrations that have been reported in surface sediments from the same geographical areaswere significant for Chacopata Lagoon, supporting a linear correlation model for manganese (r=0.533), zinc (r=0.568), nickel(r=0.696), and chromium (r=0.730). Only the linear correlation of iron was explained by its correlation coefficient (r=0.561)in Bocaripo, suggesting that this metal can be absorbed from the sediment. C. ornatus consumes surface sediments, from whereit absorbs bio-available metals like manganese, zinc, nickel, chromium (Chacopata lagoon), and iron (Bocaripo lagoon).Furthermore, it can accumulate lead, through the trophic chain, and dissolved cadmium from the water. Key words: trace metals, Callinectes ornatus, Bocaripo Lagoon, Chacopata Lagoon

No properly evaluated surfactants are currently available in Cuba for the treatment of the acute respiratory distress syndrome (ARDS), and it is not known whether SURFACEN © and the SP-A protein are suitable for the formulation of this type of product. This study evaluated the biophysical, anti-inflammatory and antimicrobial properties of SURFACEN ® , as well as the antioxidant and antibacterial activities of SP-A, to assess the potential for their use as the pharmacological basis of this new therapeutic product. Results proved that the biophysical properties of the Cuban surfactant are similar to those of the native surfactant, with superior interfacial characteristics when com- pared to CUROSURF ® and thermotropic characteristic which are qualitatively different to those of homologous preparations. Similarly, in vivo models, showed that its anti-inflammatory activity decreases pulmonary edema, myeloperoxidase activity, malondialdehyde concentrations and the total counts of inflammatory cells, restoring the normal values of the macrophage-polymorphonuclear ratio as well. A dose of 100 mg/kg, in a pleurisy model, decreased pleural exudation to levels comparable to those achieved by indomethacin. During in vitro assays, it also inhibited the production of tumor necrosis factor a (TNF α) in activated monocytes, as well as the expression of the ICAM-1 adhesion molecule in endothelial cells. Studies in five pathogenic strains proved that it exhibits antibiotic activity against Gram-positive and Gram-negative bacteria usually associated to respiratory infections. On the other hand, it is shown that pig or porcine SP-A can scavenger hydroxyl radicals and hypochlorous acid, can chelate iron, and has a protective effect in lung mitochondria and microsomes exposed to hydroxyl radicals. SP-A also protected SURFACEN ® from the oxidative action of hypochlorous acid and hydroxyl radicals, as demonstrated by the inhibition of lipid peroxidation and a lower modification of the tensoactive properties of the surfactant when treated with these chemicals, as well as by the protection of the polyunsaturated fatty acids present in SURFACEN ® . These new biophysical and immunomodulatory properties are the pharmacological supports for a prospective pharmaceu- tical formulation based on this surfactant and this protein, which can be used for the treatment of acute respiratory distress syndrome. This study contributes to the search and endorsement of a pharmaceutical formulation that may become the choice therapy for a problem that currently remains unsolved.

The antioxidant activity of Rhizophora mangle bark aqueous extract and its majoritary component and high molecular weight polyphenols' fraction were studied using deoxyribose assay. The total extract and its fraction showed scavenging activity of hydroxyl radicals and hability to chelate iron ions.

Policies, which usually govern the behaviour of networking services (e.g., security, QoS, mobility, etc.), are becoming an increasingly popular approach for the dynamic regulation of web information systems. The adoption of a policy-based approach for controlling a system requires an appropriate policy representation regarding both syntax and semantics, and the design and development of a policy management framework. In the context of the Web, the use of languages enriched with semantics (i.e. semantic languages) has been limited primarily to represent Web content and services. However the capabilities of these languages, coupled with the availability of tools to manipulate them, make them well suited for many other kinds of application, as policy representation and management. This paper provides the current trends of policy-based management enriched by semantics applied to the protection of web information systems. It also presents an approach for using DMTF Common Information Model (CIM) ontology with semantic languages.

Several recent studies in human immunodeficiency virus (HIV) patients have identified micronutrient deficiencies as affecting progression to acquired immunodeficiency syndrome (AIDS) and death. Although the mechanisms are not known, micronutrient deficiencies may exacerbate the oxidative stress induced by HIV. In addition, infection and its evolution likely lead to an increased requirement for nutritional micronutrients, especially antioxidants. To evaluate this, 40 relatively healthy, institutionalized HIV-infected individuals were recruited for assessment before or three months after fresh fruit and vegetable supply were increased due to seasonal supply. Seven-day dietary records were recorded at the beginning (December) and end of the three-month study period (March). Oxidative stress indices and CD4+, CD38+/CD8+, and CD95+ T-lymphocyte subsets were also measured at these times. No significant differences were found in calorie or protein intake across the study period, but vitamin A, C, and E intakes all increased. A number of redox indicators were modified (increase: total antioxidant status, glutathione peroxidase, and glutathione; and decrease: superoxide dismutase) during the study period. However, no change in malondialdehyde, hydroperoxides, or DNA damage was noted but a significant reduction in CD38+/CD8+ relative count was seen. Within the context and limitations of this study, the increase of dietary fruits and vegetables intake for three months had some beneficial effects on nutrition, systemic redox balance, and immune parameters in HIV-infected persons.

Superoxide dismutase (SOD) was chemically modified with carboxymethylcellulose through two different synthetic procedures: Reductive alkylation with the periodate-oxidized polymer (SOD-CMCox), and the formation of amide linkages through a carbodiimide catalyzed reaction (SODCMCedac). The SOD-CMCox and SOD-CMCedac conjugates contained about 1.8–1.2mol of polymer per mol of protein, and retained 68–78% of the initial catalytic activity, respectively. The glycosidated enzymes were more resistant to inactivation with H2O2 and their plasma half-life times were prolonged to 34.7h – 6.6h when compared with 4.8min for native SOD. The anti-inflammatory activity of the enzyme was 2–2.4 times increased after conjugation with the polymer.

The diesel engine injection system is greatly responsible for the emission of pollutants to the atmosphere, noise generation, and engine performance. Proper synchronization of the exact amount of fuel that can be burnt according to each crankshaft position is essential to achieve maximum power, consumption economy, and combustion without residues. In this sense, when designing an injection system, all of these factors must be taken into account. During the optimization, however, the improvement of some of them may result in detriment to others. For this reason, to achieve the system optimization, the relationship between the aforementioned variables and the parameters that characterize the injection must be established. According to this, it is important to design a strategy that allows the named "reverse modeling of the injection system", that is to say, to determine the injection system dimensions according to the system requirements. In the present work, an iterative computer model based on the continuity and energy equations, solved by finite differences algorithms, has been proposed. This model has been designed for a Bosch rotary pump and makes it possible to plot the performance of the pressure lines in the different combustion chambers, the valve lift curves, and the fuel flow injected per cylinder and cycle. In this sense, we can conclude that the proposed computer model predicts accurately the opening and closing processes in the injector needle, as well as the pressure curves in the last division of the high-pressure tube.

An association between viral diseases and increased oxidative stress has been suggested. The time course of serum levels of total antioxidant status (TAS), peroxidation potential (PP), glutathione (GSH), lipid peroxidation measured as hydroperoxides, and malondyaldehyde and 4-hydroxyalkenals (MDA + 4-HDA), as well as antioxidant enzymatic activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx), were measured in 22 serologically confirmed dengue patients. Most of the patients had dengue fever and three of them had dengue hemorrhagic fever. The redox parameters were compared with those of age- and sex- matched controls. No significant difference was observed for levels of GSH and TAS between patients and controls. Levels of PP, MDA + 4-HDA, and SOD were significantly higher. Levels of GPx and total hydroperoxides were significantly lower in patients in comparison with controls. These findings suggest that the alteration in redox status could result of increased oxidative stress and it may play a role in the pathogenesis of the disease.

The heavy metals Cd, Zn, Cu, Cr, Ni and Pb were determined to establish baseline levels and contamination in surface sediments of the Gulf of Cariaco, affected by industrial and urban development. Analyzed samples sediment correspond to 21 stations established along the North and South coasts and a central transect of the Gulf. The powdered sediments were digested according to the method from CARMODY et al. (1973) and additional digestion with H 2 O 2 and the quantification of the metals by Atomic Absorption Espectrometry , using a Perkin Elmer model 3110. The concentration of heavy metals in the sediments ranged from: Cd (0.00-6.21 µg/g), Zn (2.01-222.42 µg/g), Cu (0.63-67.01 µg/g), Cr (2.51-97.15 µg/g), Ni (2.01-49.87 µg/g) and Pb (0.00-37.08 µg/ g), the distribution of these trace metals was irregular, reflecting an increment of the concentration towards the central part of the Gulf. In a same way, the sediments of the North coast of the Gulf of Cariaco present higher concentrations to those obtained for the South coast, except for Pb. This can be a consequence of the circulation pattern that reigns in the Gulf, upwelling which is more intense toward the central part of the north coast of the Gulf and to the litological composition of the sediments. On the other hand, a strong anthropogenetic influence is observed that affects Pb concentrations and other metals contained in the surface sediments of this region.

Gregorio Martinez. M. Sc. en Ciencias Marinas. Profesor-Investigador Agregado, Universidad de Oriente (UDO). Coordinador del Laboratorio de Metales Trazas, Instituto Oceanografico de Venezuela (UDO). Direccion: Departamento de Oceanografia, I.O.V, UDO, Nucleo Sucre. Av. Universidad, Cerro Colorado, A.P.245,6001, Cumana, Venezuela. e-mail: gmartine@sucre.udo.edu.ve William Senior. Doctor en Quimica. Profesor-Investigador Asociado, UDO. Jefe del Departamento de Oceanografia y Coordinador de los Laboratorios de Elementos Nutritivos e Hidrocarburos, Instituto Oceanografico de Venezuela, UDO. e-mail: wsenior@ sucre.udo.edu.ve ESPECIACION DE METALES PESADOS (Cd, Zn, Cu y Cr) EN EL MATERIAL EN SUSPENSION DE LA PLUMA DEL RIO MANZANARES, VENEZUELA

Kainate induces a marked expression of cyclooxygenase-2 after its systemic administration. Because cyclooxygenase-2 activity is associated to the production of reactive oxygen species, we investigated the effects of nimesulide, a selective cyclooxygenase-2 inhibitor, on kainate-induced in vivo oxidative damage in the rat hippocampus. A clinically relevant dose of nimesulide (6 mg/kg, i.p. ) was administered three times following kainate application (9 mg/kg, i.p.). After 24 h of kainate administration, the drastic decrease in hippocampal glutathione content and the significant increase in lipid peroxidation were attenuated in nimesulide-treated rats, suggesting that the induction of cyclooxygenase-2 is involved in kainate-mediated free radicals formation.

Resumen— Las aplicaciones adaptables son un concepto clave a tener en cuenta para la transmisión de contenidos multimedia de tiempo real en entornos móviles e inalámbricos en los cuales las condiciones específicas que presenta la red son muy cambiantes y los problemas que aparecen no son únicamente debidos a la congestión -como ocurre en las redes fijas- sino debido también a interferencias en el enlace radio, movimiento de los nodos, etc. En este artículo presentamos una arquitectura para la adaptación dinámica de aplicaciones multimedia que permite minimizar de forma significativa el impacto que provoca el cambio continuo de las condiciones de la red en el nivel de aplicación. El uso de aplicaciones adaptables permite mantener la calidad de servicio percibida por los usuarios en un nivel aceptable. Se presentarán a lo largo del artículo varios resultados empíricos a partir de las pruebas realizadas sobre la arquitectura presentada.