34 research outputs found
Burnt and Blossoming: Material Mysticism in Trilogy and Four Quartets
This paper brings two WWII poems into dialogue: H.D.'s Trilogy and Eliot's Four Quartets. Both poems express a creative response to the destruction of war. My reading of Trilogy suggests a material mysticism in which vision and renewal are situated within the natural world, rituals and bodily experience. Bringing this understanding of mysticism to bear on Four Quartets reveals tension between transcendence and materiality. For Eliot, redemption comes through time and location, while for H.D., redemption lies within material particularity. Four Quartets oscillates between an apophatic discourse that seeks to transcend desire and history and an emphasis on material particularities
The P2X1 receptor and platelet function
Extracellular nucleotides are ubiquitous signalling molecules, acting via the P2 class of surface receptors. Platelets express three P2 receptor subtypes, ADP-dependent P2Y1 and P2Y12 G-protein-coupled receptors and the ATP-gated P2X1 non-selective cation channel. Platelet P2X1 receptors can generate significant increases in intracellular Ca2+, leading to shape change, movement of secretory granules and low levels of Ξ±IIbΞ²3 integrin activation. P2X1 can also synergise with several other receptors to amplify signalling and functional events in the platelet. In particular, activation of P2X1 receptors by ATP released from dense granules amplifies the aggregation responses to low levels of the major agonists, collagen and thrombin. In vivo studies using transgenic murine models show that P2X1 receptors amplify localised thrombosis following damage of small arteries and arterioles and also contribute to thromboembolism induced by intravenous co-injection of collagen and adrenaline. In vitro, under flow conditions, P2X1 receptors contribute more to aggregate formation on collagen-coated surfaces as the shear rate is increased, which may explain their greater contribution to localised thrombosis in arterioles compared to venules within in vivo models. Since shear increases substantially near sites of stenosis, anti-P2X1 therapy represents a potential means of reducing thrombotic events at atherosclerotic plaques
Number of AΞ² Inoculations in APP+PS1 Transgenic Mice Influences Antibody Titers, Microglial Activation, and Congophilic Plaque Levels
There have been several reports on the use of Ξ²-amyloid (AΞ² ) vaccination in different mouse models of Alzheimer\u27s disease (AD) and its effects on pathology and cognitive function. In this report, the histopathologic findings in the APP+PS1 doubly transgenic mouse were compared after three, five, or nine AΞ² inoculations. The number of inoculations influenced the effects of vaccination on Congo red levels, microglia activation, and anti-AΞ² antibody titers. After three inoculations, the antibody titer of transgenic mice was substantially lower than that found in nontransgenic animals. However, after nine inoculations, the levels were considerably higher in both genotypes and no longer distinguishable statistically. The number of inoculations influenced CD45 expression, an indicator of microglial activation. There was an initial upregulation, which was significant after five inoculations, but by nine inoculations, the extent of microglial activation was equivalent to that in mice given control vaccinations. Along with this increased CD45 expression, there was a correlative reduction in staining by Congo red, which stains compact plaques. When data from the mice from all groups were combined, there was a significant correlation between activation of microglia and Congo red levels, suggesting that microglia play a role in the clearance of compact plaque
Correlation between Working Memory Deficits and Cortical AΓ Deposition in Transgenic APP+PS1 Mice
Doubly transgenic mAPP+mPS1 mice (15β16 months) had impaired cognitive function in a spatial learning and memory task that combined features of a water maze and a radial arm maze. Nontransgenic mice learned a new platform location each day during 4 consecutive acquisition trials, and exhibited memory for this location in a retention trial administered 30 min later. In contrast, transgenic mice were, on average, unable to improve their performance in finding the hidden platform over trials. The cognitive performance of individual mice within the transgenic group were inversely related to the amount of AΞ²deposited in the frontal cortex and hippocampus. These findings imply that mAPP+mPS1 transgenic mice develop deficits in cognitive ability as AΞ² deposits increase. These data argue that radial arm water maze testing of doubly transgenic mice may be a useful behavioral endpoint in evaluating the functional consequences of potential AD therapies, especially those designed to reduce AΞ² load