Few data exist on the possible effects of pulp and paper effluent discharge on native fish populations in the Southern Hemisphere, relative to the research done in the Northern Hemisphere. The present research examined two native fish species (Trichomycterus areolatus and Percilia gillissi) for effects at both the molecular and individual level due to the discharge of effluent from a tertiary treated elemental chlorine-free pulp mill into a fluvial system in Central Chile over three seasons (February 2007, October 2007, January 2008). Different responses were observed between species and between sexes. There was an increase in the production of gonadal 17β-estradiol in the females of both species but a drop in 11-ketotestosterone production in P. gillissi males. Female gonadal size was increased, especially during the summer period, with corresponding increases the frequency of advanced oocyte development, and in the oocyte diameter in both species. Hepatic ethoxyresorufin-O-deethylase (EROD) activity was elevated for both species downstream of the discharge point, although overall it was higher in P. gillissi than T. areolatus. Decreases in the frequency of smaller-sized fish for both species, as well as a drop in the size of the adults downstream of the discharge point, were observed. The present study is the first evidence of endocrine disruption in native freshwater fish associated with modern pulp mills in South America. This study establishes possible links in the reproductive alterations observed at the subindividual and individual levels that could explain the changes observed at the population level.

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Industrial wastewaters and urban discharges contain complex mixtures of chemicals capable of impacting reproductive performance in freshwater fish, called endocrine-disrupting compounds (EDCs). In Chile, the issue was highlighted by our group beginning over 15 years ago, by analyzing the impacts of pulp and paper mill effluents (PPME) in the Biobio, Itata, and Cruces River basins. All of the rivers studied are important freshwater ecosystems located in the Mediterranean region of Central Chile, each with a unique fish biodiversity. Sequentially, we developed a strategy based on laboratory assays, semicontrolled-field experiments (e.g., caging) and wild fish population assessments to explore the issue of reproductive impacts on both introduced and native fish in Chile. The integration of watershed, field, and laboratory studies was effective at understanding the endocrine responses in Chilean freshwater systems. The studies demonstrated that regardless of the type of treatment, pulp mill effluents can contain compounds capable of impacting endocrine systems. Urban wastewater treatment plant effluents (WWTP) were also investigated using the same integrated strategy. Although not directly compared, PPME and WWTP effluent seem to cause similar estrogenic effects in fish after waterborne exposure, with differing intensities. This body of work underscores the urgent need for further studies on the basic biology of Chilean native fish species, and an improved understanding on reproductive development and variability across Chilean ecosystems. The lack of knowledge of the ontogeny of Chilean fish, especially maturation and sexual development, with an emphasis on associated habitats and landscapes, are impediment factors for their conservation and protection against the threat of EDCs. The assessment of effects on native species in the receiving environment is critical for supporting and designing protective regulations and remediation strategies, and for conserving the unique Chilean fish biodiversity.

Seasonal changes in oocyte development, growth and population size distribution of Percilia gillissi and Trichomycterus areolatus in the Itata basin, ChileCambio estacionales en el desarrollo de oocitos, crecimiento y distribución de talla poblacional de Percilia gillissi y Trichomycterus areolatus en la cuenca del río Itata, Chile GUSTAVO ABSTRACTThere is scarce basic biological data on native freshwater fi sh species from Chile and next to zero on growth, gonad development and reproduction, which are critical for the purposes of the conservation of their natural populations. Seasonal analysis of sub-individual (oocyte development) and population (length frequency, growth rates) endpoints in Trichomycterus areolatus and Percilia gillissi were evaluated from February 2007 to January 2008. Oocyte development has a marked seasonality for P. gillissi, with mature eggs in October and declining frequency of mature oocytes into January. For T. areolatus we found some mature eggs in July, with highest number of mature eggs in October, coincident with previous data on maximum gonad size. Both species showed a multiple spawning reproductive strategy, with a long spawning season starting in spring to early summer. Increased numbers of juveniles were observed during mid-summer for P. gillissi,and during the end of the summer and beginning of autumn for T. areolatus. Juveniles had a higher growth coeffi cient (K) (0.56-0.38 mm month-1) than adults (0.29-0.15 mm month-1), and almost all juveniles in the population reached maturity before the spring (>50 mm for T areolatus and >40 mm for P. gillissi) and were incorporated into the population as a new recruitment cohort. Knowledge of the seasonal variability of these individual and population level responses can help better understand the biology of the species, and simultaneously improve the management and conservation of freshwater biota in Chile. KEYWORDS:Seasonal cycles, native fi sh Chile, oocyte development, multiple spawning reproductive strategy, population size-structure. RESUMENExisten escasos datos de biología básica sobre las especies de peces nativas chilenas de agua dulce y casi ninguno en sobre el crecimiento, el desarrollo gonadal y reproducción, que son fundamentales para los propósitos de la conservación de sus poblaciones naturales. El análisis estacional de los parámetros sub-individuales (desarrollo de oocitos) y poblacionales (frecuencia de tallas y tasa de crecimiento) en Trichomycterus areolatus y Percilia gillissi fueron evaluados entre febrero de 2007 y enero de 2008.El desarrollo de los oocitos posee una marcada estacionalidad en P. gillissi con oocitos maduros en octubre y una disminución de estos estados maduros hacia enero. En T. areolatus encontramos oocitos maduros en Julio, pero con una mayor abundancia durante octubre, coincidente con datos previos de máximo desarrollo de la gónada. Ambas especies mostraron una estrategia reproductiva de desoves multiples, con una temporada de desove que comienza en primavera hasta principios de verano. Amb...

Una de las técnicas más comunes de tratamiento respiratorio es la nebulización de medicamentos para administrarlos por vía inhalada utilizando oxígeno como propelente, el cual a su vez es considerado un fármaco que puede generar efectos adversos relacionados con la dosificación. El objetivo de esta investigación fue diseñar, desarrollar y analizar un sistema dual de micronebulización con control preciso de la FIO2. Métodos: Se diseñó, construyó y evaluó un modelo virtual y un prototipo funcional siguiendo la metodología de bioingeniería de un nuevo dispositivo de micronebulización con control de FIO2. Se evaluó el funcionamiento del dispositivo y su impacto en voluntarios sanos y pacientes hospitalizados mediante escalas psicométricas específicas. Resultados: Se conceptualizó, diseñó y construyó un dispositivo que integra un micronebulizador (cazoleta), que permite nebulizar suero fisiológico o soluciones de diversos fármacos basado en la presurización de un gas propelente (aire u oxígeno) junto a un mecanismo de ajuste de la fracción inspirada de O2 (mínimo, 21%; máximo de 99%). Los límites (máximo y mínimo) de flujo recomendado para generar el aerosol son 6-8 l/min. En ningún caso de uso se presentaron complicaciones. Conclusiones: CONTROLizer es un dispositivo integrado dual y no-invasivo para la micronebulización de soluciones respiratorias y control continuo de la fracción inspirada de oxígeno. Por sus cualidades y funcionamiento, el dispositivo fue percibido como adecuado y seguro para aplicarse en individuos sanos y pacientes ingresados tanto en salas de cuidados intensivos como de hospitalización convencional.