73 research outputs found
Magnetic resonance detects metabolic changes associated with chemotherapy-induced apoptosis
Apoptosis was induced by treating L1210 leukaemia cells with mechlorethamine, and SW620 colorectal cells with doxorubicin. The onset and progression of apoptosis were monitored by assessing caspase activation, mitochondrial transmembrane potential, phosphatidylserine externalization, DNA fragmentation and cell morphology. In parallel, 31P magnetic resonance (MR) spectra of cell extracts were recorded. In L1210 cells, caspase activation was detected at 4 h. By 3 h, the MR spectra showed a steady decrease in NTP and NAD, and a significant build-up of fructose 1,6-bisphosphate (F-1,6-P) dihydroxyacetonephosphate and glycerol-3-phosphate, indicating modulation of glycolysis. Treatment with iodoacetate also induced a build-up of F-1,6-P, while preincubation with two poly(ADP-ribose) polymerase inhibitors, 3-aminobenzamide and nicotinamide, prevented the drop in NAD and the build-up of glycolytic intermediates. This suggested that our results were due to inhibition of glyceraldehyde-3-phosphate dehydrogenase, possibly as a consequence of NAD depletion following poly(ADP-ribose) polymerase activation. Doxorubicin treatment of the adherent SW620 cells caused cells committed to apoptosis to detach. F-1,6-P was observed in detached cells, but not in treated cells that remained attached. This indicated that our observations were not cell line- or treatment-specific, but were correlated with the appearance of apoptotic cells following drug treatment. The 31P MR spectrum of tumours responding to chemotherapy could be modulated by similar effects
Insect threats and conservation through the lens of global experts
While several recent studies have focused on global insect population trends, all are limited in either space or taxonomic scope. As global monitoring programs for insects are currently not implemented, inherent biases exist within most data. Expert opinion, which is often widely available, proves to be a valuable tool where hard data are limited. Our aim is to use global expert opinion to provide insights on the root causes of potential insect declines worldwide, as well as on effective conservation strategies that could mitigate insect biodiversity loss. We obtained 753 responses from 413 respondents with a wide variety of spatial and taxonomic expertise. The most relevant threats identified through the survey were agriculture and climate change, followed by pollution, while land management and land protection were recognized as the most significant conservation measures. Nevertheless, there were differences across regions and insect groups, reflecting the variability within the most diverse class of eukaryotic organisms on our planet. Lack of answers for certain biogeographic regions or taxa also reflects the need for research in less investigated settings. Our results provide a novel step toward understanding global threats and conservation measures for insects.Peer reviewe
Mourning and Longing: Media Studies learning to let go of liberal democracy
In her essay âNeoliberalism and the end of liberal democracyâ, Wendy Brown suggests that critical political theory needs to âmourn liberal democracyâ in order to develop a transformative vision of âthe goodâ. The problem, as Brown outlines it, is not only that â to varying extents and in different scales across democratic states â market rationality has hollowed out representative structures and processes and organizes social life but also that âbasic principles and institutions of democracy are becoming nothing other than ideological shellsâ that nevertheless legitimate neoliberal governmentality. Brownâs concept of mourning has implications for Media Studiesâ constitutive focus on publicness and political participation within the democratic nation-state. This article considers Brownâs critique in relation to the tendency in Media Studies to admit the unachievable idealism of certain ideas â particularly in relation to the public sphere and pluralism â while continuing to use them as guiding normative standards and values. The article questions how such normative ideals can provide guidance where not only the political and institutional imaginary that underpins them has changed, perhaps irrevocably, but where the continued flagging of these ideas may be implicated in the kind of ideological camouflage Brown identifies
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