The protective role of transferrin in Müller glial cells after iron-induced toxicity.

International audiencePURPOSE: Transferrin (Tf) expression is enhanced by aging and inflammation in humans. We investigated the role of transferrin in glial protection. METHODS: We generated transgenic mice (Tg) carrying the complete human transferrin gene on a C57Bl/6J genetic background. We studied human (hTf) and mouse (mTf) transferrin localization in Tg and wild-type (WT) C57Bl/6J mice using immunochemistry with specific antibodies. M?r glial (MG) cells were cultured from explants and characterized using cellular retinaldehyde binding protein (CRALBP) and vimentin antibodies. They were further subcultured for study. We incubated cells with FeCl(3)-nitrilotriacetate to test for the iron-induced stress response; viability was determined by direct counting and measurement of lactate dehydrogenase (LDH) activity. Tf expression was determined by reverse transcriptase-quantitative PCR with human- or mouse-specific probes. hTf and mTf in the medium were assayed by ELISA or radioimmunoassay (RIA), respectively. RESULTS: mTf was mainly localized in retinal pigment epithelium and ganglion cell layers in retina sections of both mouse lines. hTf was abundant in MG cells. The distribution of mTf and hTf mRNA was consistent with these findings. mTf and hTf were secreted into the medium of MG cell primary cultures. Cells from Tg mice secreted hTf at a particularly high level. However, both WT and Tg cell cultures lose their ability to secrete Tf after a few passages. Tg MG cells secreting hTf were more resistant to iron-induced stress toxicity than those no longer secreted hTf. Similarly, exogenous human apo-Tf, but not human holo-Tf, conferred resistance to iron-induced stress on MG cells from WT mice. CONCLUSIONS: hTf localization in MG cells from Tg mice was reminiscent of that reported for aged human retina and age-related macular degeneration, both conditions associated with iron deposition. The role of hTf in protection against toxicity in Tg MG cells probably involves an adaptive mechanism developed in neural retina to control iron-induced stress

L’invention technique et théorique : la philosophie des sciences de G. Bachelard

International audienceSciences produce what Bachelard names phenomenotechnic inventions. This permanent inventiveness which makes of the man a “mutant species” is present in the technological and intellectual novation of any scientific projection. Culture and philosophy remain behind, foreign with this inventiveness. We will try in this communication to characterize : 1) the philosophy "bachelardienne" of the “4th state” (that which produces noumenes in the experiment), 2) originality of the proposal (not comtienne, non Cartesian, non Kantian, anti bergsonienne, foreign with analytical philosophy. This philosopher antinaturalist, antirealist, materialist and rationalist in a very particular direction however provide a set of concepts very highly lighting and useful to define the technological and political innovation. Whereas the philosophical community is rather concerned to take as a starting point Simondon, or Social Sciences Studies (of Bruno Latour for example), Bachelard is forgotten whereas it provides a bouquet of stimulative ideas. Through the restitution of his philosophy, one more generally wishes to contribute to give again life at the French School of epistemology, which, from Comte to Foucault, produced a tradition strongly critical, at the same time as favorable to sciences and technophile (contrary to the German School, from Heidegger to Habermas). Concerning the question of imaginary and technical invention and innovation, Bachelard gives us stimulative instruments and something to lean on, particularly in these three works: Le Rationalisme appliqué, 1949, L'Activité rationaliste de la physique contemporaine, 1951, Le Matérialisme rationnel,, 1953. It does not approach the invention from the point of view of lived subjective or creative experiments (Ribot, Bergson) but starting from the objective scientific knowledge, from the experimentation, much richer and full of daring.Les sciences produisent ce que Bachelard nomme des inventions phénoménotechni-ques. Cette inventivité permanente qui fait de l'homme une "espèce mutante" est présente dans la novation technologique et intellectuelle de toute avancée scientifique. Culture et phi-losophie restent en arrière, étrangère à cette inventivité. On s'attardera dans cette communication à caractériser : 1) la philosophie bachelardienne du "4e état" (celui qui produit des noumènes dans l'expérience), 2) l'originalité de la proposition (non comtienne, non cartésien-ne, non kantienne, anti bergsonienne, étrangère à la philosophie analytique. Ce philosophe antinaturaliste, antiréaliste, matérialiste et rationaliste en un sens très particulier fournit pour-tant un ensemble de notions très vivement éclairantes et utiles pour définir l'innovation tech-nologique et politique. 2 L'invention technique et théorique : la philosophie des sciences de G. Bachelard Bachelard philosophe des sciences est oublié dans le débat contemporain sur les technoscien-ces et l'innovation. Ce philosophe anti-naturaliste, anti-réaliste, matérialiste et rationaliste en un sens très particulier fournit pourtant un ensemble de notions très vivement éclairantes et utiles pour structurer le débat actuel. Alors que la communauté philosophique est plutôt soucieuse de s'inspirer de Simondon, ou des Social Sciences Studies (de Bruno Latour en particulier), Bachelard est oublié alors qu'il fournit un bouquet d'idées stimulantes. A travers la restitution de sa philosophie, on souhaite plus généralement contribuer à redonner vie à l'École française d'épistémologie, qui, de Comte à Foucault, a produit une tradition à la fois puissamment critique, en même temps que favorable aux sciences et technophile (contraire-ment à l'École allemande, de Heidegger à Habermas). Pour ce qui concerne la question de l'imaginaire et de l'invention technique, de l'innovation, Bachelard nous donne des instruments et des points d'appui stimulants, particulièrement dans ces trois ouvrages : Le Rationalisme appliqué, 1949, L'Activité rationaliste de la physique contemporaine, 1951, Le Matérialisme rationnel, 1953. Il n'aborde pas l'invention du point de vue du vécu subjectif ou d'expériences créatrices (Ribot, Bergson) mais à partir de la connaissance scientifique objective, de l'expérimentation, beaucoup plus riche et audacieuse

Stress in Prefixed Disyllabic Verb/Noun Pairs

International audienceSummary of stress variation, data consistency between dictionaries, and detailed analysis of two parameters: frequency (from COCAE data) and vowel quality (full and/or reduced vowe

L'agent glottopolitique et son glossaire. Enjeux de représentations des langues chez trois romanciers hétérolingues

International audienceQuand dire, c’est feindre…L’analyse des emprunts aux langues endogènes dans les romans hétérolingues génère une interrogation sur leur dimension mimétique. Si la critique linguistique et la sociocritique des littératures francophones tendent à percevoir les romans hétérolingues comme représentatifs des contextes plurilingues, en revanche les partisans de l’hétérolinguisme mettent en évidence la dimension illusoire de cette représentation. Quand dire, c’est faire...En revanche, le glossaire des écrivains hétérolingues tend à imposer en langue les emprunts, dévoilant ainsi sa portée glottopolitique. Les pratiques glossairistiques spécifiques des écrivains peuvent ainsi être mises en relation avec leurs représentations épilinguistiques déclarées, comme avec celles des locuteurs endogènes de la société dont ils émanent. L’analyse de trois romans francophones (Le Jujubier du Patriarche, d’Aminata Sow Fall, 1993, Allah n’est pas obligé, de Kourouma, 2000, et Le Rocher de Tanios, de Maalouf, 1993) révèle l’intérêt des comparaisons du glossaire des écrivains pour découvrir plus en profondeur la spécificité de leur rapport à la langue littéraire

A link at infinity for minimal surfaces in R4\mathbb{R}^4

We look at complete minimal surfaces of finite total curvature in $\mathbb{R}^4$. Similarly to the case of complex curves in $\mathbb{C}^2$ we introduce their link at infinity; we derive the writhe number at infinity which gives a formula for the total normal curvature of the surface. The knowledge of the link at infinity can sometimes help us determine if a surface has self-intersection and we illustrate this idea by looking at genus zero surfaces of small total curvature

Population genomics of eusocial insects: the costs of a vertebrate-like effective population size

International audienceThe evolution of reproductive division of labour and social life in social insects has lead to the emergence of several life-history traits and adapta-tions typical of larger organisms: social insect colonies can reach masses of several kilograms, they start reproducing only when they are several years old, and can live for decades. These features and the monopolization of reproduction by only one or few individuals in a colony should affect molecular evolution by reducing the effective population size. We tested this prediction by analysing genome-wide patterns of coding sequence polymor-phism and divergence in eusocial vs. noneusocial insects based on newly generated RNA-seq data. We report very low amounts of genetic polymor-phism and an elevated ratio of nonsynonymous to synonymous changes – a marker of the effective population size – in four distinct species of eusocial insects, which were more similar to vertebrates than to solitary insects regarding molecular evolutionary processes. Moreover, the ratio of nonsyn-onymous to synonymous substitutions was positively correlated with the level of social complexity across ant species. These results are fully consistent with the hypothesis of a reduced effective population size and an increased genetic load in eusocial insects, indicating that the evolution of social life has important consequences at both the genomic and population levels

Video games and urban simulation: new tools or new tricks?

International audienceVideo games allow complex systems modelling, revealing retroaction loops, replicating self-organization and the emergence of hierarchical organization, functional differentiation and social segregation through multi-level interactions. Recent trends focus on improving modelling tools’ graphic quality and interface attractiveness and on using video games to facilitate urban studies teaching and research. This apparent convergence between simulation and video games is addressed through a selection of strategy and city builder video games. Comparisons reveal that simulations and video games point to similar results:, they both allow the simulation of complex urban processes, like hierarchical urban networks or urban segregation. Games even seem to allow going one step further, being often more comprehensive simulations. However, the main limitation of video games emerges from their didactic power: video games and simulation software implement rules and models in almost opposite means. Games induce players to learn the model but not to challenge or to produce new knowledge

Not Always the Same Old Story: Spatial Segregation and Feelings of Dislike against Roma and Sinti in Large Cities and Medium-size Towns in Italy

The scientific literature on the dynamics of public opinion and racism as a whole has neglected the spread of anti-gypsy feeling . Only recently, with the Europeanization of the Roma Movements' claims, have official data from public opinion research made it possible to reach any empirically-based conclusions on the spread of anti-gypsy prejudice in Europe. The availability of these data has not yet been fully exploited, and at the same time their use, albeit only partial, has not been critically worked out. On the other hand we know that the use of opinion polls within the public sphere cannot be ignored, because of the resulting reification of the prejudice and the effects on the objectified ethnic category. This will be the focus of discussion for this chapter, which will introduce unpublished analysis and focus on the Italian situation, showing how pragmatic reflection on the use of data may make it possible to tackle the main risks that these investigations entail. We will also be careful not to ignore the political relevance taken on by the research, even if, no doubt, this will have contradictory effects as well

Particle Deposition in a Child Respiratory Tract Model: <I>In Vivo</I> Regional Deposition of Fine and Ultrafine Aerosols in Baboons

International audienceTo relate exposure to adverse health effects, it is necessary to know where particles in the submicron range deposit in the respiratory tract. The possibly higher vulnerability of children requires specific inhalation studies. However, radio-aerosol deposition experiments involving children are rare because of ethical restrictions related to radiation exposure. Thus, an in vivo study was conducted using three baboons as a child respiratory tract model to assess regional deposition patterns (thoracic region vs. extrathoracic region) of radioactive polydisperse aerosols ([d16-d84], equal to [0.15 μm-0.5 μm], [0.25 μm-1 μm], or [1 μm-9 μm]). Results clearly demonstrated that aerosol deposition within the thoracic region and the extrathoraic region varied substantially according to particle size. High deposition in the extrathoracic region was observed for the [1 μm-9 μm] aerosol (72% ± 17%). The [0.15 μm-0.5 μm] aerosol was associated almost exclusively with thoracic region deposition (84% ± 4%). Airborne particles in the range of [0.25 μm-1 μm] showed an intermediate deposition pattern, with 49% ± 8% in the extrathoracic region and 51% ± 8% in the thoracic region. Finally, comparison of baboon and human inhalation experiments for the [1 μm-9 μm] aerosol showed similar regional deposition, leading to the conclusion that regional deposition is species-independent for this airborne particle sizes

Pointwise estimates and existence of solutions of porous medium and pp-Laplace evolution equations with absorption and measure data

Let $\Omega$ be a bounded domain of $\mathbb{R}^{N}(N\geq 2)$. We obtain a necessary and a sufficient condition, expressed in terms of capacities, for existence of a solution to the porous medium equation with absorption \begin{equation*} \left\{ \begin{array}{l} {u_{t}}-{\Delta }(|u|^{m-1}u)+|u|^{q-1}u=\mu ~ \text{in }\Omega \times (0,T), \\ {u}=0~~~\text{on }\partial \Omega \times (0,T), \\ u(0)=\sigma , \end{array} \right. \end{equation*} where $\sigma$ and $\mu$ are bounded Radon measures, $q>\max (m,1)$, $m>\frac{N-2}{N}$. We also obtain a sufficient condition for existence of a solution to the $p$-Laplace evolution equation \begin{equation*} \left\{ \begin{array}{l} {u_{t}}-{\Delta _{p}}u+|u|^{q-1}u=\mu ~~\text{in }\Omega \times (0,T), \\ {u}=0 ~ \text{on }\partial \Omega \times (0,T), \\ u(0)=\sigma . \end{array} \right. \end{equation*} where $q>p-1$ and $p>2$