Regulating macrophage phenotype and function by retinal pigment epithelial cells

Purpose: We have shown previously that macrophages/microglia accumulate in the subretinal space and express CD68 and Arginase-1 in the aging eye. Subretinal macrophages are in close contact with retinal pigment epithelial (RPE) cells. We hypothesize that RPE cells may play an important role in regulating macrophage/microglial phenotype and function. The aim of this study was to investigate the effect of RPE cells on the phenotype and function of bone marrow–derived macrophages (BM-DMs).
Methods: BM-DM from C57BL/6J mice were cultured in DMEM supplemented with 20%L929 cell supernatant for 5 days. The phenotype of BM-DMs was confirmed by flow cytometry as CD11b+F4/80+. Primary RPE cells were cultured from C57BL/6J mice and confirmed by RPE65 and cytokeratin staining. BMDMs were co-cultured with different types of RPE cells (healthy, oxidized, and apoptotic RPE) and then isolated from the co-culture system for phenotypic and functional assays.
Results: Co-culture of BM-DMs with RPE cells results in a time-dependent down-regulation of MHC-II expression and the generation of CD11b+F4/80+Ly6G+ myeloid-derived suppressor cells (MDSC). qRT-PCR analysis showed that RPE-induced MDSCs expressed high levels of IL-6, IL-1β, and Arginase-1, but lower levels of IL-12p40 and TNF-a compared to naïve BM-DMs. The expression levels of iNOS, TGF-β and Ym1 did not differ 207 between naive BMDMs and RPE-induced MDSCs. Furthermore, functional studies showed that these cells had reduced phagocytic activity and lower ability to stimulate T cell activation and proliferation. When RPE cells were pre-treated with oxidized photoreceptor outer segments before co-culturing with BMDMs, the expression of IL-1β and IL-6 in BMDMs was increased whereas the expression of Arginase-1 was decreased. 
Conclusion: Our results suggest that healthy RPE cells can convert BMDMs into myeloid-derived suppressor cells under in vitro culture conditions, RPE-induced myeloid-derived suppressor cells are CD11b+F4/80+Ly6G+MHCIIlowIL6+IL1b+Arg-1+. The ability of RPE cells is reduced when suffering from oxidative insults.

A 'ruin of all space, shattered glass and toppling masonry': Joyce's Orientalism in the Context of 11 September 2001 and 1922

Chapters 3 and 15 of Joyce's Ulysses exhibit glimpses of three dreams, fantasies and eventual nightmares linked to the figure of 'Haroun al Raschid.' Historically speaking, the latter was a powerful Caliph of Baghdad, a medieval potentate about whom many of the most memorable of The Thousand and One Nights or The Arabian Nights' Entertainments were once and then again spun as tales of pleasure. Joyce seizes upon the figure of 'Haroun al Raschid' as a fictive measure to articulate the 'orientalist' fantasies of Stephen Dedalus and Leopold Bloom. However, this evocative figure of Near Eastern history, of fabulous narrative and the progressively converging fantasies of two modern European literary characters is riddled with paradox. Such material provides Joyce a perceptive and proleptic sense of the paradoxes and brutal historical contradictions through which Western and Eastern dreams of theocratic nationalism, ethnic zealotry, colonial rebellion and Zionism are to be played out. W. B. Yeats' poem 'The Gift of Harun al-Raschid', written in 1923, the year after the book publication of Ulysses, provides both a fitting foil and a significant socio-historical point of reference for Joyce's own figurative use of the Caliph of Baghdad.

Performing Space

This article discusses how the notion of performance provides impetus for the design of interactive digital environments. These environments can ultimately be regarded as user-spaces; a condition which replaces the "fixed" art-object with a configuration of interactions. Our understanding of space, as suggested by Lefevbre (2001), defines the "inhabitant" as a full participant, a user, a performer of space. What is at play when the installation artist designs environments that invite performative exploration? The issue of improvised performance in the inhabiting of installation spaces is exposed. Two interactive installations by the author and works by others in the field provide a context for discussion for discussion and analysis.

Models of open populations with space-limited recruitment: extension of theory and application to the barnacle Chthamalus montagui.

1. Barnacles are a good model organism for the study of open populations with space-limited recruitment. These models are applicable to other species with open supply of new individuals and resource limitation. The inclusion of space in models leads to reductions in recruitment with increasing density, and thus predictions of population size and stability are possible. 2. Despite the potential generality of a demographic theory for open space-limited populations, the models currently have a narrow empirical base. In this study, a model for an open population with space-limited recruitment was extended to include size-specific survival and promotions to any size class. The assumptions of this model were tested using data from a pan-European study of the barnacle Chthamalus montagui Southward. Two models were constructed: a 6-month model and a periodic annual model. Predicted equilibria and their stabilities were compared between shores. 3. Tests of model assumptions supported the extension of the theory to include promotions to any size class. Mortality was found to be size-specific and density independent. Studied populations were open, with recruitment proportional to free space. 4. The 6-month model showed a significant interaction between time and location for equilibrium free space. This may have been due to contrasts in the timing of structuring processes (i.e. creating and filling space) between Mediterranean and Atlantic systems. Integration of the 6-month models into a periodic annual model removed the differences in equilibrium-free space between locations. 5. Model predictions show a remarkable similarity between shores at a European scale. Populations were persistent and all solutions were stable. This reflects the apparent absence of density-dependent mortality and a high adult survivorship in C. montagui. As populations are intrinsically stable, observations of fluctuations in density are directly attributable to variations in the environmental forcing of recruitment or mortality