Fetal exposure to bisphenol A as a risk factor for the development of childhood asthma: an animal model study

<p>Abstract</p> <p>Background</p> <p>The prevalence of asthma in industrialized countries has been increasing dramatically and asthma is now the most common chronic disease of children in the United States. The rapidity of the increase strongly suggests that changes in environmental exposures are the likely cause of this epidemic. Further, the early onset of allergic manifestations suggests that these exposures may act on the prenatal development of the immune system. We have focused on the potential effects of bisphenol A (BPA), a chemical pollutant with one of the largest productions, on the development of childhood asthma. We have reported that perinatal BPA exposure promotes the development of allergic asthma in a mouse model. The current study was designed to identify a critical period of BPA exposure and to begin elucidating the mechanisms for this susceptibility.</p> <p>Methods</p> <p>Female BALB/c mice received 10 micro g/ml BPA in their drinking water from one week before pregnancy until the end of the study. Some of the pups were transferred in the first 48 h of life from their BPA-loaded mother to an unexposed mother, or vice versa. Half of the pups were sensitized with a low dose of the experimental allergen ovalbumin (OVA), the rest received PBS as an unsensitized controls. On day 22, the pups were challenged by inhalations of ovalbumin or PBS followed by quantification of eosinophils in and hyperreactivity of their airways, major indicators of experimental asthma in this classical mouse model. Hepatic expression of two isoforms of UDP-glucuronosyltransferase (Ugt) was quantified by quantitative RT-PCR at various ages.</p> <p>Results</p> <p>Pups exposed to BPA in utero and through breast milk, or in utero only, displayed an asthma phenotype in response to their "suboptimal" allergic sensitization, whereas, pups only exposed to BPA postnatally from breast milk, did not. The expression of Ugt2b1, an isoform related to BPA clearance in rats, was not detectable in mouse fetuses and newborn pups, but increased by day 5 and approached adult levels by day 25.</p> <p>Conclusions</p> <p>Prenatal exposures that produce environmentally relevant burdens of BPA, followed by postnatal allergic sensitization and challenges, promote the development of experimental allergic asthma. Delayed expression of BPA-metabolizing enzymes may explain, at least in part, the enhanced fetal susceptibility to this common environmental contaminant.</p

Considerations for the development of Computer-assisted Language Learning (CALL) teacher training course: a practical experience from a CALL course development in Indonesia

The need for technology training for teachers will keep on growing in line with the development of technology itself. Although technology nowadays is more and more user friendly and may need no specific training on how to use it, teachers need to possess the knowledge that underpins the idea of using it for teaching and learning process. Teachers need to have solid pedagogical knowledge on how to use the technology to deliver contents to their students. Therefore, a technology-training course for teachers is always necessary. This paper presents the partial results of a design based study/research (DBR) on the development of online technology training for teachers with focus on CALL in Indonesia. Questions regarding factors affecting online CALL course and ways to improve the course in terms of training materials, activities, as well as the administration of the training are addressed in the study. Based on the study, some considerations on how to design such technology-training course are proposed. The considerations are ranging from aspects associated with technology competence for teacher standards, constructivism in online learning, adult learning theory, online instructional models, the technology, pedagogy and content knowledge (TPACK) framework and open educational resources (OER). Information regarding those aspects will be useful to assist other CALL teacher training course developers later to inform their decision in the development of the course which is based on a good theoretical understanding as well as highly practical in learning activitie

Modelli di e-learning

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The teacher’s professional profile in ICT for education

EDEN - European Distance and E Learning Networ