4,392 research outputs found
Plasticizers as endocrine disruptors: the case of the endocannabinoid system in teleost species
No full textPlasticizers, as Bisphenol A (BPA) and Di-isononyl phthalate (DiNP), are chemicals added to the plastics to improve their performance, which recently, turned into a ubiquitous in the environment due to the high rate of use and manufacture of plastic, and hence, of the plasticizers. BPA and DiNP have been found in all environmental matrices, being bioavailable for organisms and reported as endocrine-disrupting chemicals (EDCs). On the other hand, the endocannabinoid system (ECS), a novel lipid signaling system lately defined, has been proposed as a new target for the potential effects of the EDCs. The ECS has been described in several species and it has an essential role for the well-being of the organisms. For that, the main goal of the present project was to assess the effects of BPA and DiNP in the ECS of Danio rerio and Sparus aurata. To accomplish this objective D. rerio and S. aurata were chronically treated (3 weeks) with BPA and DiNP, separately, via water or via food respectively. Generally, the results for both species, showed a deregulation of the ECS at central (brain) and peripheral level (liver and gonads) at mRNA and protein level, the alteration of the hepatic lipid metabolism and the biochemical composition of liver in both species. In the gonads, the reproductive performance measured as fertility rate, the gonadal morphology and sexual hormone levels were also altered by the treatments of both pollutants. In conclusion, the chronic exposure to environmental concentrations of BPA and DiNP induced alterations at the ECS pathway in Danio rerio and Sparus aurata. Finally, the ECS can be considered as new target for EDCs such as BPA and DiNP
Amyloodinum ocellatum in Dicentrarchus labrax: Study of infection in salt water and freshwater aquaponics
No full textEndocrine-disrupting chemicals in aquatic environment: what are the risks for fish gametes?
No full textOver the past 25 years, extensive research in vertebrate species has identified several genomic pathways altered by exposures to anthropogenic chemicals with hormone-like activity mediated by their interaction with nuclear receptors. In addition, many pollutants have been shown to interfere with non-genomic (non-classical) pathways, but this mechanism of endocrine disruption is still poorly understood. Recently, the number of publications describing the effects of Endocrine disrupting chemicals (EDCs) on fish reproduction, focusing on the deregulation of the hypothalamus-pituitary-gonadal axis as well as on gamete quality, significantly increased. Depending on their ability to mimic endogenous hormones, the may differently affect male or female reproductive physiology. Inhibition of gametogenesis, development of intersex gonads, alteration of the gonadosomatic index, and decreased fertility rate have been largely documented. In males, alterations of sperm density, motility, and fertility have been observed in several wild species. Similar detrimental effects were described in females, including negative outcomes on oocyte growth and maturation plus the occurrence of apoptotic/autophagic processes. These pathways may affect gamete viability considered as one of the major indicators of reproductive endocrine disruption. Pollutants act also at DNA level producing DNA mutations and changes in epigenetic pathways inducing specific mechanisms of toxicity and/or aberrant cellular responses that may affect subsequent generation(s) through the germline. In conclusion, this review summarizes the effects caused by EDC exposure on fish reproduction, focusing on gametogenesis, giving a general overview of the different aspects dealing with this issue, from morphological alteration, deregulation of steroidogenesis, hormonal synthesis, and occurrence of epigenetic process
Diets contaminated with Bisphenol A and Di-isononyl phtalate modify skeletal muscle composition: A new target for environmental pollutant action
No full textEffects of diisononyl phthalate on Danio rerio reproduction
No full textDi-isononyl phthalate (DiNP) is a high molecular weight phthalate commonly used as a plasticizer. It was introduced as a replacement for bis (2-ethylhexyl) phthalate (DEHP) which is used in the production of plasticized polyvinyl chloride (PVC). The purpose of this study was to investigate for the first time the effect of DiNP on female reproductive physiology in Danio rerio. Fish were exposed to five different doses of DiNP plus control (0 μg/L; 0.42 μg/L; 4.2 μg/L; 42 μg/L; 420 μg/L; 4200 μg/L) for a period of 21 days. We evaluated fish fecundity, oocyte growth, autophagic and apoptotic processes, as well as changes in morphological and biochemical composition of oocytes, using, qPCR analysis, histology and Fourier transform infrared imaging. The results demonstrate a non-monotonic dose response to DiNP. Greater differences were observed at the lowest (0.42 μg/L) and higher concentrations (420 μg/L; 4200 μg/L) of DiNP. The findings provide evidence that exposure to DiNP adversely affect oocytes growth and maturation, leading to abnormal gonadal development and reproduction in zebrafish
Role of Bisphenol A on the Endocannabinoid System at central and peripheral levels: Effects on adult female zebrafish
No full textEffects of diethylene glycol dibenzoate and Bisphenol A on the lipid metabolism of Danio rerio
No full textEffects of BPA on zebrafish gonads: Focus on the endocannabinoid system
No full textBisphenol A (BPA), a monomer used for polycarbonate manufacture, has been widely reported as an endocrine-disrupting chemical (EDC). Among other alterations, BPA induces reproductive dysfunctionalities. Changes in the endocannabinoid system (ECS) have been recently shown to be associated with reproductive disorders. The ECS is a lipid-based signaling system (cannabinoid receptors, endocannabinoids and enzymatic machinery) involved in several physiological functions. The main goal of the present study was to assess the effects of two environmental concentrations of BPA (10 and 20 μg/L) on the ECS in 1-year old zebrafish gonads. In males, BPA increased the gonadosomatic index (GSI) and altered testicular levels of endocannabinoids as well as reduced the testicular area occupied by spermatogonia. In male liver, exposure to 20 μg/L BPA significantly increased vitellogenin (vtg) transcript levels. In female zebrafish, BPA altered ovarian endocannabinoid levels, elevated hepatic vtg mRNA levels as well as increased the percentage of vitellogenic oocytes in the ovaries. In conclusion, exposure to two environmentally relevant concentrations of BPA altered the ECS and consequently, gonadal function in both male and female zebrafish
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Daughter of fortune: Isabel Allende's popularity from a readership perspective
No full textThe primary aim of this thesis is to explore and critically interrogate Isabel Allende’s popularity cross-culturally in Britain and Spain. It analyses readers’ responses to Allende’s works as well as the discourses surrounding her public representation, an approach that is ‘readerly’ but must also take account of production and text. This approach is intended to further the understanding of Allende’s work which so far has always been analysed from a textual perspective. However, the relationship between Allende’s popularity, her texts, public representation and readers has not been yet analysed in detail.This thesis is innovative in other ways too. Methodologically, it approaches readers through the under studied cultural form of the reading group. It also incorporates a comparative dimension by looking at the reception of Allende in two different cultural contexts: the British and Spanish respectively. Finding out about Allende’s popularity has involved asking readers about their reading experiences as well as analysing the production of discourses around her public representation. Paul Ricoeur’s (1984, 1988) perspective on authorial intentions and readers’ responses to texts helps in understanding the intricacies surrounding what is involved in reading any text. It draws attention to Allende’s and her publishers’ authorial strategies, her ‘strategies of persuasion’ and the specificity of the lives and contexts of British and Spanish reading publics. Equally, this ‘readerly’ approach draws on feminist audience research and primarily on the work of Ien Ang and Janice Radway. Their work with viewers and readers respectively is particularly useful in establishing and developing methodological parameters for the study of reading groups. As a whole, this thesis contributes to the understanding of Allende’s cross-cultural popularity by situating readers at the centre
Tetraplejia traumática tras fractura vertebral cervical: estudio comparativo de tratamiento conservador y quirúrgico
No full textTesis de la Universidad Complutense de Madrid, Facultad de Medicina, Departamento de Medicina Física y de Rehabilitación (Hidrología Médica), leída el 17-12-2010El objetivo del estudio es comparar los resultados del tratamiento conservador y el tratamiento quirúrgico en una muestra de 140 pacientes con lesión medular cervical traumática, con respecto a la recuperación neurológica, complicaciones, estancias hospitalarias y dolor a largo plazo. Se distinguieron los factores clínicos relacionados con la recuperación neurológica y se evaluó el beneficio del tratamiento con corticoides a altas dosis según la pauta NASCIS. La media global de mejoría fue de 0,44 grados de ASIA de media y de 0,86 niveles de ASIA de media. La mejora neurológica, en cuanto a niveles de ASIA, fue mayor en los pacientes tratados quirúrgicamente que en el grupo conservador (p= 0,046). Un 9,6% de lesiones completas presentó cierta recuperación neurológica, pasando a in-completas. Tanto las lesiones completas como las incompletas se han beneficiado del tratamiento quirúrgico, aunque la recuperación fue mayor en la puntuación motora de las lesiones completas intervenidas. Hubo una tendencia a una mayor frecuencia de complicaciones en el grupo conser-vador, si bien no alcanzó significación estadística (p= 0,832). En cuanto al beneficio de la administración de corticoides, no encontramos diferencias en la recuperación neurológica ni en la frecuencia de complicaciones médicas. El dolor en la fase aguda en el foco de fractura fue más frecuente en los pacientes sometidos a tratamiento conservador que en el grupo quirúrgico, sin diferencias entre los tipos de cirugía. No se pudo demostrar que la cirugía evitara la deformidad ni la inestabilidad vertebral. En el dolor a largo plazo no hubo diferencias entre el tratamiento quirúrgico y el conservador. El tratamiento quirúrgico no consiguió acortar el periodo de encamamiento ni la estancia hospitalaria total.Depto. de Radiología, Rehabilitación y FisioterapiaFac. de MedicinaTRUEpu
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