RESUMEN
Ecological effects of gold nano-particles (AuNP) are examined due to growing use in consumer and industrial materials. This study investigated uptake and movement of AuNPs through an aquatic food chain. Simple (single-species) and diverse (multi-species) periphyton communities were exposed to AuNP (0, 100, 500 µg L-1 treatments). AuNP quickly aggregated and precipitated from the water column, suggesting it is an insignificant route of AuNP exposure even at elevated concentrations. Gold was measured in 100 and 500 µg L-1 periphyton treatments. Gold accumulation was similar between periphyton treatments, suggesting physical processes were important for AuNP basal accumulation. Hyalella azteca and Lymnea stagnalis whole body tissue analysis indicated gold accumulation may be attributed to different feeding mechanisms, general versus selective grazing, respectively. Results suggest trophic transfer of AuNP is organism specific and aggregation properties of AuNP are important when considering fate of nano-particles in the environment and movement through aquatic food webs.
Asunto(s)
Anfípodos/efectos de los fármacos , Oro/análisis , Lymnaea/efectos de los fármacos , Nanopartículas del Metal/análisis , Perifiton/efectos de los fármacos , Contaminantes Químicos del Agua/análisis , Anfípodos/química , Animales , Exposición Dietética , Cadena Alimentaria , Lymnaea/química , Especificidad de la EspecieRESUMEN
BACKGROUND: Mortality in severe acute renal failure (ARF) requiring renal replacement therapy (RRT) approximates 50% and varies with clinical severity. Continuous RRT (CRRT) has theoretical advantages over intermittent hemodialysis (IHD) for critical patients, but a survival advantage with CRRT is yet to be clearly demonstrated. To date, no prospective controlled trial has sufficiently answered this question, and the present prospective outcome study attempts to compare survival with CRRT versus that with IHD. METHODS: Multivariable Cox-proportional hazards regression was used to analyze the impact of RRT modality choice (CRRT vs. IHD) on in-hospital and 100-day mortality among ARF patients receiving RRT during 2000 and 2001 at University of Michigan, using an "intent-to-treat" analysis adjusted for multiple comorbidity and severity factors. RESULTS: Overall in-hospital mortality before adjustment was 52%. Triage to CRRT (vs IHD) was associated with higher severity and unadjusted relative rate (RR) of in-hospital death (RR = 1.62, p = 0.001, n = 383). Adjustment for comorbidity and severity of illness reduced the RR of death for patients triaged to CRRT and suggested a possible survival advantage (RR = 0.81, p = 0.32). Analysis restricted to patients in intensive care for more than five days who received at least 48 hours of total RRT, showed the RR of in-hospital mortality with CRRT to be nearly 45% lower than IHD (RR = 0.56, n = 222), a difference in RR that indicates a strong trend for in-hospital mortality with borderline statistical significance (p = 0.069). Analysis of 100-day mortality also suggested a potential survival advantage for CRRT in all cohorts, particularly among patients in intensive care for more than five days who received at least 48 h of RRT (RR = 0.60, p = 0.062, n = 222). CONCLUSION: Applying the present methodology to outcomes at a single tertiary medical center, CRRT may appear to afford a survival advantage for patients with severe ARF treated in the ICU. Unless and until a prospective controlled trial is realized, the present data suggest potential survival advantages of CRRT and support broader application of CRRT among such critically ill patients.
Asunto(s)
Lesión Renal Aguda/diagnóstico , Lesión Renal Aguda/terapia , Terapia de Reemplazo Renal/métodos , APACHE , Lesión Renal Aguda/mortalidad , Adulto , Anciano , Estudios de Cohortes , Cuidados Críticos/métodos , Femenino , Estudios de Seguimiento , Hemofiltración/métodos , Humanos , Unidades de Cuidados Intensivos , Pruebas de Función Renal , Masculino , Persona de Mediana Edad , Análisis Multivariante , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Diálisis Renal/métodos , Medición de Riesgo , Índice de Severidad de la Enfermedad , Tasa de Supervivencia , Resultado del TratamientoRESUMEN
Injured tissue is characterized by increased glucose uptake and increased lactate production as compared to normal tissue. These metabolic changes have been attributed to the presence of inflammatory cells in injured tissues. To correlate these metabolic changes with changes in the inflammatory cell population at various times after injury, we studied the lambda-carrageenan hindlimb wound model in anesthetized rats. Perfusion studies demonstrated that at 3 and 5 days after injury glucose uptake was increased in injured hindlimbs, compared with hindlimbs from pair-fed control animals. At 3, 5, and 10 days after injury, lactate production from glucose was increased in injured hindlimbs, compared with hindlimbs from pair-fed control animals. These metabolic changes were not related to differences in body weight or food intake. There was no difference in glucose oxidation or in oxygen consumption in injured hindlimbs, compared with hindlimbs from pair-fed control animals. The increased glucose uptake and increased lactate production from glucose was coincident with the presence of inflammatory cells--predominantly macrophages--at the site of injury. It is suggested that the glucose metabolism in injured tissue reflects the metabolism of the inflammatory cells at the site of injury.
Asunto(s)
Glucosa/metabolismo , Músculos/metabolismo , Heridas y Lesiones/metabolismo , Animales , Glucemia/metabolismo , Radioisótopos de Carbono , Carragenina , Inflamación , Lactatos/metabolismo , Masculino , Consumo de Oxígeno , Perfusión , Técnica de Dilución de Radioisótopos , Ratas , Ratas Endogámicas , Valores de Referencia , Factores de TiempoRESUMEN
The elderly Chicano comprise a population that is distinct in historical background, socialization patterns, coping mechanisms, and patterns of participation in community affairs. These distinctive characteristics have often been overlooked by community planners who know little about elderly Chicanos and assume that all their needs can be met by their families. Several strategies are proposed for the development of participatory processes and systems that take into account the reality of daily life in the barrio. Statistical data should be enriched by qualitative information for decision-making purposes: the calm rationality of one set of people discussing the problems of others should be balanced by the fire of people describing their own experiences.
Asunto(s)
Anciano/psicología , Hispánicos o Latinos/psicología , Conducta Social , Adulto , Demografía , Humanos , Modelos Psicológicos , Motivación , Política , Calidad de Vida , Ajuste Social , Apoyo Social , Servicio Social , Estados UnidosRESUMEN
Important in the development of research-based practice models is the impact on them of program design. In this article, the concept of program design is reduced to elements that can be examined for their reliability, validity, relevance, and internal consistency. Defining these elements contributes to understanding what types of interventions have what effects on what types of clients with what types of problems.