865 resultados para inferior cava vein obstruction


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AR

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Left ventricular outflow tract (LVOT) defects are an important group of congenital heart defects (CHDs) because of their associated mortality and long-term complications. LVOT defects include aortic valve stenosis (AVS), coarctation of aorta (CoA), and hypoplastic left heart syndrome (HLHS). Despite their clinical significance, their etiology is not completely understood. Even though the individual component phenotypes (AVS, CoA, and HLHS) may have different etiologies, they are often "lumped" together in epidemiological studies. Though "lumping" of component phenotypes may improve the power to detect associations, it may also lead to ambiguous findings if these defects are etiologically distinct. This is due to potential for effect heterogeneity across component phenotypes. ^ This study had two aims: (1) to identify the association between various risk factors and both the component (i.e., split) and composite (i.e., lumped) LVOT phenotypes, and (2) to assess the effect heterogeneity of risk factors across component phenotypes of LVOT defects. ^ This study was a secondary data analysis. Primary data were obtained from the Texas Birth Defect Registry (TBDR). TBDR uses an active surveillance method to ascertain birth defects in Texas. All cases of non complex LVOT defects which met our inclusion criteria during the period of 2002–2008 were included in the study. The comparison groups included all unaffected live births for the same period (2002–2008). Data from vital statistics were used to evaluate associations. Statistical associations between selected risk factors and LVOT defects was determined by calculating crude and adjusted prevalence ratio using Poisson regression analysis. Effect heterogeneity was evaluated using polytomous logistic regression. ^ There were a total of 2,353 cases of LVOT defects among 2,730,035 live births during the study period. There were a total of 1,311 definite cases of non-complex LVOT defects for analysis after excluding "complex" cardiac cases and cases associated with syndromes (n=168). Among infant characteristics, males were at a significantly higher risk of developing LVOT defects compared to females. Among maternal characteristics, significant associations were seen with maternal age > 40 years (compared to maternal age 20–24 years) and maternal residence in Texas-Mexico border (compared to non-border residence). Among birth characteristics, significant associations were seen with preterm birth and small for gestation age LVOT defects. ^ When evaluating effect heterogeneity, the following variables had significantly different effects among the component LVOT defect phenotypes: infant sex, plurality, maternal age, maternal race/ethnicity, and Texas-Mexico border residence. ^ This study found significant associations between various demographic factors and LVOT defects. While many findings from this study were consistent with results from previous studies, we also identified new factors associated with LVOT defects. Additionally, this study was the first to assess effect heterogeneity across LVOT defect component phenotypes. These findings contribute to a growing body of literature on characteristics associated with LVOT defects. ^

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An observational study was conducted in a SICU to determine the frequency of subclavian vein catheter-related infection at 72 hours, to identify the hospital cost of exchange via a guidewire and the estimated hospital cost-savings of a 72 hour vs 144 hour exchange policy.^ An overall catheter-related infection ($\geq$15 col. by Maki's technique (1977)) occurred in 3% (3/100) of the catheter tips cultured. Specific infections rates were: 9.7% (3/31) for triple lumen catheters, 0% (0/30) for Swan-Ganz catheters, 0% (0/30) for Cordes catheters, and 0% (0/9) for single lumen catheters.^ An estimated annual hospital cost-savings of $35,699.00 was identified if exchange of 72 hour policy were changed to every 144 hours.^ It was recommended that a randomized clinical trial be conducted to determine the effect of changing a subclavian vein catheter via a guidewire every 72 hours vs 144 hours. ^

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En este trabajo se evalúa el comportamiento del nivel freático (NF) en un área de regadío de 75.774 ha ubicadas en el tercio inferior de la cuenca del río Atuel, departamentos de General Alvear y San Rafael en la provincia de Mendoza, y su vinculación con: las pérdidas que se producen en la red de canales, las prácticas de riego y los escurrimientos sub-superficiales de zonas más elevadas. En la zona existe una red de 193 freatímetros en la que se han registrado lecturas de niveles freáticos desde 1980 a 2008, en distintas estaciones del año. El área de estudio se dividió en cuatro sub-zonas, cada una de ellas abastecida por un canal matriz de riego. La serie existente de lecturas de NF permitió elaborar planos estacionales de isohipsas e isobatas medias. Se definieron indicadores de factor de reacción freática (FRF) y de eficiencia del sistema (IES); además, se elaboraron planos de isolíneas y tablas de salinidad (conductividad eléctrica) media del agua subterránea. El análisis de los registros recopilados muestra la dirección del flujo de agua subterránea "noroeste-sureste", isohipsas con un gradiente medio de 1,54 m.Km-1 y nivel freático (NF) con una profundidad mínima media de 1.31 m. La evidencia de zonas de recarga de agua subterránea posibilita, junto a los otros planos, una rápida identificación de zonas vulnerables al ascenso del NF. El FRF permitió establecer que se incorpora al área cultivada de Alvear-Bowen un volumen de 3,7 veces más agua que la requerida por los cultivos y que el IES es del 27%. En primavera, el riego representa el 66% del volumen incorporado a la zona mientras que las precipitaciones representan el 34 % y la superficie con NF de hasta 1,0 m de profundidad es 4,8 veces mayor al promedio del área afectada en las demás estaciones. Los resultados brindan una fuente de información actualizada para la planificación del uso del suelo en la zona, para la operación del sistema de riego y para la implementación y priorización de planes de mejora en la infraestructura.

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La odontología está inmersa en un nuevo paradigma: no se puede pensar en ninguna técnica restauradora sin que participen fenómenos de adhesión. El desarrollo de pernos de fibra de vidrio, sumado a los procedimientos de restauraciones adhesivas puede utilizarse como uno de los tantos recursos de la odontología de invasión mínima. Los pernos de fibra de vidrio ofrecen varias ventajas: comportamiento anisótropo, módulo de elasticidad bajo, buena resistencia mecánica, el lecho que aloja al perno de fibra requiere de una mínima preparación y se cementan con cementos adhesivos con carga, permitiendo de esta manera obtener una superficie homogénea que se interpone entre el perno de fibra y los tejidos dentales, conectándolo a los tejidos del conducto y sustituyendo mecánicamente la dentina. El caso clínico que se reporta se presentó para su resolución en la Clínica Integrada III F. O. UNCuyo durante el año lectivo 2009. El paciente presentaba una fractura amelodentinaria desde hacía cuatro años, con compromiso de la vitalidad y un proceso periapical. Durante los procedimientos endodónticos se realizó una perforación de la pared del conducto que se selló mediante la colocación de hidróxido de calcio y la obturación del mismo con conos de gutapercha. Se efectuó el seguimiento clínico y radiográfico del caso en donde se constató la reparación del proceso apical y luego se procedió a la restauración del elemento dentario con resinas compuestas con la ayuda de un poste de fibra de vidrio cementado con cemento resinoso. Dadas las características del tratamiento endodóntico realizado, se decidió dejar más porción del cono de gutapercha a pesar de lo aconsejado por numerosos autores, ya que de esta manera se aseguró el sellado de la perforación radicular para evitar de esta manera la nanofiltración hacia el interior del elemento dentario.

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Vein smectites with large Rb/Sr enrichments from extensively altered basaltic oceanic crust in Deep Sea Drilling Project hole 417A in the western Atlantic define a highly constrained Rb/Sr isochron age of 108 +/- 3 m.y. This age is identical to a less well constrained age of 108 +/- 17 m.y. for vein smectites with lower Rb/Sr enrichments from adjacent hole 418A and to the 108 m.y. age of crust formation derived by paleontological and magnetic anomaly correlation. Reasonable agreement exists between the 87Sr/86Sr ratio of vein calcites from both sites and the seawater 87Sr/86Sr ratio at the time. Pervasive low-temperature alteration in the contrasting environments of sites 417 and 418 appears to be coeval and essentially coincident with basement formation. Alteration may be used to advantage in determining ages of old oceanic crust.

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Fil: Baldino, Juan Marcos. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

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Fil: Baldino, Juan Marcos. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

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Fil: Baldino, Juan Marcos. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

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Cation exchange experiments (ammonium acetate and cation resin) on celadonite-smectite vein minerals from three DSDP holes demonstrate selective removal of common Sr relative to Rb and radiogenic Sr. This technique increases the Rb/Sr ratio by factors of 2.3 to 22 without significantly altering the age of the minerals, allowing easier and more precise dating of such vein minerals. The ages determined by this technique (Site 261 - 121.4+/-1.6 m.y.; Site 462A - 105.1+/-2.8 m.y.; Site 516F - 69.9+/-2.4 m.y.) are 34, 54 and 18 m.y. younger, respectively, than the age of crust formation at the site; in the case of site 462A, the young age is clearly related to off-ridge emplacement of a massive sill/flow complex. At the other sites, either the hydrothermal circulation systems persisted longer than for normal crust (10-15 m.y.), or were reactivated by off-ridge igneous activity. Celadonites show U and Pb contents and Pb isotopic compositions little changed from their basalt precursors, while Th contents are significantly lower. Celadonites thus have unusually high alkali/U,Th ratios and low Th/U ratios. If this celadonite alteration signature is significantly imprinted on oceanic crust as a whole, it will lead to very distinctive Pb isotope signatures for any hot spot magmas which contain a component of aged subducted recycled oceanic crust. Initial Sr isotope ratios of ocean crust vein minerals (smectite, celadonite, zeolite, calcite) are intermediate between primary basalt values and contemporary sea water values and indicate formation under seawaterdominated systems with effective water/rock ratios of 20-200.