914 resultados para Séneca, Lucio Anneo, ca. 4 a.C.-65 d.C..
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Revisión sistemática de la literatura tomando ensayos clínicos aleatorizados sobre el uso de la inyección intraprostática de la toxina botulínica en los pacientes con hiperplasia prostática benigna evaluando una escala validada de síntomas del tracto urinario bajo como desenlace primario
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Breve reseña de la vida de Lucio Anneo Séneca, el filósofo español más destacado del Imperio Romano, y de la evolución de su pensamiento según los acontecimientos que presencia y sufre, en especial, el destierro durante ocho años en la inhóspita isla de Córcega por una falsa acusación de adulterio, que le marcó profundamente.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Background: Cytotoxic T lymphocyte-associated factor 4 (CTLA-4) functions as a negative regulator of T cell-mediated immune response. Molecular changes associated to CTLA-4 gene polymorphisms could reduce its ability to suppress and control lymphocyte proliferation. Aims: To evaluate the frequency of CTLA-4 gene polymorphisms in chronic hepatitis C virus (HCV) infected patients and correlate to clinical and histological findings. Methods: We evaluated 112 HCV-infected subjects prospectively selected and 183 healthy controls. Clinical and liver histological data were analysed. - 318C > T, A49G and CT60 CTLA-4 single-nucleotide polymorphisms (SNPs) were studied by PCR-RFLP and AT(n) polymorphism by DNA fragment analysis by capillary electrophoresis in automatic sequencer. Results: Eight AT repetitions in 3' UTR region were more frequent in HCV-infected subjects. We found a positive association of -318C and + 49G with HCV genotype 3 (P = 0.008, OR 9.13, P = 0.004, OR 2.49 respectively) and an inverse association of both alleles with HCV genotype 1 (P = 0.020, OR 0.19, P = 0.002, OR 0.38 respectively). Allele + 49G was also associated to aminotransferases quotients > 3 (qALT, P = 0.034, qAST, P = 0.041). Allele G of CT60 SNP was also associated with qAST > 3 (P = 0.012). Increased number of AT repetitions was positively associated to severe necroinflammatory activity scores in liver biopsies (P = 0.045, OR 4.62). Conclusion: CTLA-4 gene polymorphisms were associated to HCVinfection. Eight AT repetitions were more prevalent in HCV-infected subjects. - 318C and + 49G alleles were associated to genotypes 1 and 3 infections and increased number of AT repetitions in 3' UTR region favoured severe necroinflammatory activity scores in liver biopsies.
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Providing care to a spouse with Alzheimer's disease (AD) may contribute to cardiovascular disease (CVD). The acute phase reactant C-reactive protein (CRP) is a well-established biomarker of an increased CVD risk.
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BACKGROUND: Hepatic steatosis may promote progression of chronic hepatitis C (CHC). Microsomal triglyceride transfer protein (MTP) is required for assembly and secretion of ApoB lipoprotein and is implicated in hepatitis C virus (HCV)-related steatosis. The MTP -493G/T polymorphism may promote liver fat accumulation, but its role in HCV-related steatosis is still unclear. METHODS: Two hundred ninety-eight CHC patients were studied and genotyped for MTP -493G/T variants. Hepatic MTP mRNA expression and activity were determined in a subgroup. RESULTS: Patients with grades 2/3 steatosis were older, had a higher body mass index (BMI), more advanced fibrosis and lower MTP mRNA expression and carried more often HCV genotype 3 and the MTP T allele. Age, BMI, HCV-3 and MTP T allele [odds ratio (OR) 2.05; 95% confidence interval (CI) 1.2-3.53; P=0.009] were independent risk factors for steatosis grades 2/3, and in HCV genotype non-3 patients, the MTP T allele was the strongest predictor for steatosis grade 2/3 (OR 2.17; 95% CI 1.22-3.86; P=0.008). Moreover, TT carriers had higher high-density lipoprotein (65.6+/-14.6 vs 56.1+/-16.2 mg/dl; P=0.003) and apolipoprotein AI (1.80+/-0.3 vs 1.60+/-0.3 g/L; P=0.005) levels than G allele carriers. CONCLUSIONS: Chronic hepatitis C patients with the MTP -493T allele reveal higher grades of steatosis, indicating a relevant contribution to liver fat accumulation, particularly in HCV non-3 patients.
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Thermal acclimation is frequently cited as a means by which ectothermic animals improve their Darwinian fitness, i.e. the beneficial acclimation hypothesis. As the critical swimming speed (U (crit)) test is often used as a proxy measure of fitness, we acclimated Atlantic cod (Gadus morhua) to 4 and 10 degrees C and then assessed their U (crit) swimming performance at their respective acclimation temperatures and during acute temperature reversal. Because phenotypic differences exist between different populations of cod, we undertook these experiments in two different populations, North Sea cod and North East Arctic cod. Acclimation to 4 or 10 degrees C had a minimal effect on swimming performance or U (crit), however test temperature did, with all groups having a 10-17% higher U (crit) at 10 degrees C. The swimming efficiency was significantly lower in all groups at 4 degrees C arguably due to the compression of the muscle fibre recruitment order. This also led to a reduction in the duration of "kick and glide" swimming at 4 degrees C. No significant differences were seen between the two populations in any of the measured parameters, due possibly to the extended acclimation period. Our data indicate that acclimation imparts little benefit on U (crit) swimming test in Atlantic cod. Further efforts need to identify the functional consequences of the long-term thermal acclimation process.
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Based on benthic and planktic foraminifera, Bolboforma, oxygen isotope measurements and seismic data, major changes in Miocene, Pliocene and Pleistocene paleoenvironments on the mid Norwegian shelf are discussed and a possible scenario of the late Cenozoic uplift history is given. The dating of the Neogene sequence has been done using foraminifera and Bolboforma. Four main assemblage zones have been identified with nine distinct subzones. Most of the Miocene sequence is preserved. The lower Miocene sediments contain only siliceous microfossils. A period of high fertility and upwelling in the study area prevailed. The early Miocene-early mid Miocene (15 Ma?) change from a siliceous to a calcareous rich microfauna, dominated by Nonion barleeanum, can be related to increased surface-water circulation due to overflow across the Iceland-Faeroe ridge. During the Miocene the temperature decreased in the study area. Evidence of increased amounts of coarser sediments may suggest that an uplift of the mainland areas occurred during the mid-late Miocene. Lower Pliocene sediments contain a foraminiferal fauna that seems to occur in slightly colder conditions than the late Miocene fauna suggesting a further cooling. Possibly, Arctic waters entered the study area in the early Pliocene. A very marked change in lithology (from compacted claystone to unconsolidated diamicton), fauna (from deep dwelling to shallow dwelling species) and seismic signature (from flat lying reflectors to prograding clinoforms) occurs during the mid?-late Pliocene. A two step cooling trend is indicated by the microfauna of these prograding wedges. (1) The first wedge buildups might have been associated with an uplift of the mainland during the early late Pliocene (mid Pliocene, ca. 4 Ma). However, the age determination is somewhat uncertain and may very well be of late Pliocene age. (2) The second step of wedge buildup is associated with a glacial phase where the dominating microfauna exists of arctic species. Large continental ice sheets might have occurred at this time reaching coastal areas and that possibly many of the geomorphological features such as the strandflat were made during this episode. The Pleistocene epoch is represented by an increased percentage of boreal foraminifera intermingled with high arctic species which indicates that interglacial-glacial cycles prevailed and the dynamics of the glacier system changed.
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La nitrificación-desnitrificación es el proceso biológico tradicional para la remoción de nitrógeno de las aguas residuales (Ruiz G. et al., 2006a), siendo fundamental ya que contribuye a controlar la eutroficación de los cuerpos receptores. Debido al deterioro que sobre la disponibilidad de los recursos han ejercido las actividades antropogénicas, es necesario orientar el tratamiento de las aguas residuales hacia tecnologías que ofrezcan el mayor grado de sustentabilidad, planteando innovaciones en el tratamiento. El presente proyecto de tesis doctoral versa sobre el estudio de la influencia de la relación C/N en la desnitrificación y metanogénesis de aguas residuales urbanas en un reactor anaeróbico de lecho fluidizado inverso (RLFI). Previamente a la realización de las pruebas experimentales de variación de la relación C/N, se llevó a cabo la etapa de arranque del RLFI la cual se inició en modo batch, favoreciendo la formación y adhesión de biopelícula al medio de soporte utilizado (Extendosphere). Después, sobrevino la operación en modo continuo desde una carga volumétrica aplicada (CVA) de 0.5 g DQOs/L⋅d hasta alcanzar 4 g DQOs/L⋅d, carga volumétrica a la cual se logró la plena estabilización del reactor, siendo la alta variabilidad de la concentración de DQOs en el agua residual urbana de alimentación, la principal problemática que ocasionó retrasos en la estabilidad del reactor. A una CVA de 4 g DQOs/L⋅d en estado estacionario, el valor mínimo de eficiencia de remoción de DQOs fue del 32.36% y el máximo de 66.99%. En estas condiciones el porcentaje de metano presente en el biogás producido tuvo un valor medio de 85.57 ± 2.93%, siendo un valor alto comparado con otros porcentajes de metano encontrados en la digestión anaerobia de aguas residuales urbanas. El YCH4 tuvo un valor medio de 0.316 ± 0.110 LCH4/g DQOrem⋅día. Los porcentajes de metanización variaron en el rango de 20.50 a 100%, registrándose un valor medio de 73.42 ± 25.63%. La considerable variabilidad en el porcentaje de metanización se debió principalmente a que se presentaron eventos de lavado de soporte colonizado, lo cual propició que las actividades metabólicas fueran orientadas hacia formación de biopelícula (anabolismo) en vez de estar dirigidas hacia producción de metano (catabolismo). En relación a los ensayos con variación de la relación C/N, se manejaron relaciones DQOs/N-NO3 en el rango de 1.65 a 21.1 g DQOs/g N-NO3. La tasa de remoción anaerobia de DQOs se incrementó con la concentración de sustrato en una relación casi lineal, ajustándose a una cinética de primer orden, lo que regularmente se presenta a concentraciones bajas de sustrato. La eficiencia del proceso de desnitrificación fue por lo regular alta, incrementándose ligeramente con la concentración de DQOs en el influente, con valores en el rango de 73.8 a 99.1%. Por otra parte, la tasa de remoción por metanogénesis se incrementó con la concentración relativa de sustrato (es decir, a mayores relaciones DQOs/N-NO3), siendo más sensitiva la metanogénesis a la concentración relativa de sustrato que la desnitrificación. Conforme aumentó la relación DQOs/N-NO3, la desnitrificación, de ser la ruta metabólica principal de utilización de la materia orgánica (comparada con la metanización), empezó a combinarse con la metanización. De manera evidente, a las relaciones DQOs/N-NO3 probadas, se manifestaron más las actividades desnitrificantes, quedando reflejadas por el alto porcentaje de utilización de la DQOs removida hacia la desnitrificación. La relación experimental DQOs/N-NO3 a la cual se pudiera haber cumplido con el requerimiento de materia orgánica (en términos de DQOs) para la desnitrificación de nitratos en las aguas residuales urbanas tratadas resultó aproximadamente ser igual a 7.1 g DQOs/g N-NO3. A una CVA de 4 g DQOs/L⋅d, se obtuvo un diámetro promedio máximo de soporte colonizado igual a 266.106 ± 69.279 μm aunque, hay que indicarlo, se presentaron fluctuaciones, las cuales se reflejaron también en el espesor de la biopelícula, el cual tuvo un valor máximo de 50.099 μm y un valor promedio de 37.294 ± 11.199 μm. Estas fluctuaciones pudieron deberse a la existencia de corrientes preferenciales dentro del reactor, las cuales no permitieron un acceso equitativo del sustrato a todo el lecho. Nitrification-denitrification is the traditional biological process for nitrogen removal from wastewaters (Ruiz G. et al., 2006a), being fundamental since it contributes to control the eutrophication of the receiving waters. Due to the deterioration that on the availability of the aquatic resources the anthropogenic activities have exerted, it is necessary to orient the treatment of wastewaters towards technologies that offer the greater degree of sustainability, raising innovations in the treatment. This work studied the influence of C/N ratio on denitrification and methanogenesis of urban wastewaters in an inverse fluidized bed reactor (IFBR). Previously to the accomplishment of the experimental tests with variation of C/N ratio, the start up of the IFBR was carried out in batch way, encouraging the formation and adhesion of biofilm to Extendosphere, which it was used as support. The operation in continuous way carried out from an organic loading rate (OLR) of 0.5 g CODs/L ∙ d to 4 g CODs/L ∙ d, when the steady-state was reached. The high variability of the CODs of the urban wastewaters caused delays in the stability of the reactor. Once stationary state was reached, the removal efficiency of CODs ranged from 32.36 to 66.99% to 4 g CODs/L ∙ d. In these conditions the percentage of methane in produced biogas had an average value of 85.57 ± 2.93%, being a high value compared with other studies treating anaerobically urban wastewaters. The YCH4 had an average value of 0.316 ± 0.110 LCH4/g CODrem ∙ d. The percentage of methanisation ranged from 20.50 to 100%, with an average value of 73.42 ± 25.63%. The considerable variability in the methanisation percentage occurred mainly due events of wash-out of colonized support, which caused that the metabolic activities were oriented towards formation of biofilm (anabolism) instead of methane production (catabolism). Concerning the tests with variation of C/N ratio, CODs/NO3-N ratios from 1.65 to 21.1 g CODs/g NO3-N were proved. The CODs anaerobic removal rate increased with the substrate concentration in an almost linear relation, adjusting to a kinetic of first order, which regularly appears to low concentrations of substrate. Efficiency of the denitrification process was regularly high, and it increased slightly with the CODs concentration in the influent, ranging from 73.8 to 99.1%. On the other hand, the CODs removal rate by methanogenesis increased with the substrate relative concentration (e.g., to greater CODs/NO3-N ratios), being more sensitive the methanogenesis to the substrate relative concentration that the denitrification. When the CODs/NO3-N ratio increased, the denitrification, of being the main metabolic route of use of the organic matter (compared with the methanogenesis), began to be combined with the methanogenesis. Definitively, to the proven CODs/NO3-N ratios the denitrification processes were more pronounced, being reflected by the high percentage of use of the removed CODs towards denitrification. The experimental CODs/NO3-N ratio to which it was possible to have been fulfilled the requirement of organic matter (in terms of CODs) for the denitrification of nitrates in urban wastewaters turned out to be approximately 7.1 g CODs/g NO3-N. It was obtained a maximum average diameter of colonized support of 266.106 ± 69.279 μm to 4 g CODs/L ∙ d, although it is necessary to indicate that appeared fluctuations in the thickness of biofilm, which had a maximum value of 50.099 μm and an average value of 37.294 ± 11.199 μm. These fluctuations could be due to the existence of preferential currents within the reactor, which did not allow an equitable access of the substrate to all the bed.
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Inositol phosphates are a family of water-soluble intracellular signaling molecules derived from membrane inositol phospholipids. They undergo a variety of complex interconversion pathways, and their levels are dynamically regulated within the cytosol in response to a variety of agonists. Relatively little is known about the biological function of most members of this family, with the exception of inositol 1,4,5-trisphosphate. Specifically, the biological functions of inositol tetrakisphosphates are largely obscure. In this paper, we report that D-myo-inositol 3,4,5,6-tetrakisphosphate (D-Ins(3,4,5,6)P4) has a direct biphasic (activation/inhibition) effect on an epithelial Ca(2+)-activated chloride channel. The effect of D-Ins(3,4,5,6)P4 is not mimicked by other inositol tetrakisphosphate isomers, is dependent on the prevailing calcium concentration, and is influenced when channels are phosphorylated by calmodulin kinase II. The predominant effect of D-Ins(3,4,5,6)P4 on phosphorylated channels is inhibitory at levels of intracellular calcium observed in stimulated cells. Our findings indicate the biological function of a molecule hitherto considered as an "orphan" messenger. They suggest that the molecular target for D-Ins(3,4,5,6)P4 is a plasma membrane Ca(2+)-activated chloride channel. Regulation of this channel by D-Ins(3,4,5,6)P4 and Ca2+ may have therapeutic implications for the disease states of both diabetic nephropathy and cystic fibrosis.
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Mode of access: Internet.
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Mode of access: Internet.