2 resultados para Subversive activities

em Deakin Research Online - Australia


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"Step up and play" begins the famous hit song 'Penny Arcade'. And so it
was for thousands of Australian families, as their eldest child began school
this year, and the associated endless merry-go-round of extra-curricular
activities also began. But how many of those families realise that the song ends "Roll up and spend your last dime!"? While the perceived benefits of
children's involvement in extracurricular activities are many and are widely accepted, there are also costs, not only in terms of money but also in terms
of time. Evidence from a study conducted in Melbourne highlights the fact that, for many families such as those on low incomes and those headed by a single parent, both the time and the money costs may be prohibitive. This article highlights parents' perceptions of the benefits·and costs of children's extra-curricular activities, and explores the implications of changing family and household structures for families' capacity to sustain such activities.

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Inorganic arsenic (jAs), a known human carcinogen, acts as a tumor promoter in part by inducing a rapid burst of reactive oxygen species (ROS) in mammalian cells. This causes oxidative stress and a subsequent increase in the level of cellular glutathione (GSH). Glutathione, a ubiquitous reducing sulfhydryl tripeptide, is involved in ROS detoxification and its increase may be part of an adaptive response to the oxidative stress. Glutathione related enzymes including glutathione reductase (GR) and glutathione S-transferase (GST) also play key roles in these processes. In this study the regulatory effects of inorganic arsenite (As111) on the activities of GSH-related enzymes were investigated in cultured human keratinocytes. Substantial increases in GR enzyme activity and mRNA levels were shown in keratinocytes and other human cell lines after exposure to low, subtoxic, micromolar concentrations of As111 for 24 h. Upregulation of GSH synthesis paralleled the upregulation of GR as shown by increases in glutamatecysteine lyase (GeL) enzyme activity and mRNA levels, cystine uptake, and intracellular GSH levels. Glutathione S-transferase activity was also shown to increase slightly in keratinocytes, but not in fibroblasts or breast tumor cells. Overall the results show that sublethal arsenic induces a multicomponent response in human keratinocytes that involves upregulation of parts, but not all of the GSH system and counteracts the acute toxic effects of jAs. The upregulation of GR has not previously been shown to be an integral part of this response, although GR is critical for maintaining levels of reduced GSH.