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Brigitte Chamak

Bio: Brigitte Chamak is an academic researcher from Paris Descartes University. The author has contributed to research in topics: Autism & Social movement. The author has an hindex of 19, co-authored 64 publications receiving 1732 citations. Previous affiliations of Brigitte Chamak include Centre national de la recherche scientifique & Collège de France.


Papers
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TL;DR: The results suggest that brain macrophages could favour the appearance of neuroregressive events which occur either during neurogenesis or in neurodegenerative diseases, implying intracerebral recruitment of mononuclear phagocytes.
Abstract: Brain macrophages are transiently present in different regions of the central nervous system during development or in the course of tissue remodelling following various types of injuries. To investigate the influence of these phagocytes on neuronal growth and survival, brain macrophages stemming from the cerebral cortex of rat embryos were added to neuronal primary cultures. A neurotoxic effect of brain macrophages was demonstrated by the reduction of the number of neurons bearing neurites within two days of contact between the two cell types. Neuronal death and phagocytosis were also directly observed in video recordings of living cultures. This toxicity involved the production by brain macrophages of reactive oxygen intermediates, as shown by the protective effect of catalase, a scavenger of H2O2. In addition, the respiratory bursts of brain macrophages were stimulated in the presence of neurons. These results suggest that brain macrophages could favour the appearance of neuroregressive events which occur either during neurogenesis or in neurodegenerative diseases, implying intracerebral recruitment of mononuclear phagocytes.

202 citations

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TL;DR: The observations strongly suggest that the astrocytic environment regulates the synthesis and/or intracellular distribution of MAP2, as well as the morphology of the neurons, and that this regulation is region specific.
Abstract: Embryonic neurons from the rat striatum and mesencephalon were plated on mesencephalic or striatal astrocytes in 4 possible combinations. It was found that specific traits are expressed by the neurons when they are grown on homotopic astrocytes (neurons and astrocytes from the same region). These traits are the following: 1. The number of cells stained with an antibody raised against the microtubule-associated protein 2 (MAP2) is higher in homotopic than in heterotopic cocultures. This is true for both mesencephalic and striatal neurons. 2. In homotopic conditions, there is an increase in the number of cells having more primary neurites and branching points. This effect is observed for both neuronal populations but is more pronounced in mesencephalic neurons. 3. The intensity of MAP2 staining was correlated with the branching ability of the neurons. First, on comparing MAP2-positive and MAP2-negative cells, it was found that, in any combination (homotopic and heterotopic cocultures), the number of primary neurites and branching points was much higher in MAP2-positive cells. In fact, almost no branching activity was found in MAP2-negative neurons. Second, within the MAP2-positive neuronal population, the higher number of branching points observed under homotopic neuro-astroglial conditions was mostly due to the neuritic compartment, which was strongly and homogeneously stained with the anti-MAP2 antibody. These observations strongly suggest that the astrocytic environment regulates the synthesis and/or intracellular distribution of MAP2, as well as the morphology of the neurons, and that this regulation is region specific.

201 citations

Journal ArticleDOI
TL;DR: It is suggested that both the autism-category changes in the late 1980s, and the development of educational and behavioural methods in the United States, have given rise to a large-scale mobilisation around the changes inThe definition of autism and interventions in many countries.
Abstract: The aim of this empirical investigation is to analyse the social movements brought about by autism-related issues. It is suggested that both the autism-category changes in the late 1980s, and the development of educational and behavioural methods in the United States, have given rise to a large-scale mobilisation around the changes in the definition of autism and interventions in many countries. The present paper highlights the historical dynamics of the mobilisation of French parents' associations and the engagement of autistic persons' organisations. The role of the French parents' associations has been studied over the last 40 years to show how they have contributed to shaping public policy in France and how they have favoured the American model of autism despite the French professionals' resistance. At the international level, the newly-born associations of autistic individuals have introduced new actors who sometimes reproach the parents' associations for speaking on their behalf. These new associations, such as self-help groups, have a political identity problem. Their members no longer want to be considered as patients but as individuals with a different cognitive mode of functioning. Their actions can be analysed in the broader context of the disability movement. If the disability movement is considered as the latest generation of social movements, the action of autistic persons can be viewed as the latest generation of the disability movements.

162 citations

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TL;DR: The results suggest that brain macrophages contribute actively to neurite growth or regeneration during the development or in pathological contexts.
Abstract: The presence of macrophages in the developing or lesioned central nervous system (CNS) led us to study the influence of these cells on neuronal growth. Macrophages were isolated from embryonic rat brain and we observed that factors released in vitro by these cells stimulate neurite growth and regeneration of cultured CNS neurons. This effect was inhibited by antibodies directed against thrombospondin, an extracellular matrix protein that we found to be synthesized and released by brain macrophages. Immunodetection of thrombospondin in the adult rat brain lesioned by kainic acid confirmed the production of this protein by brain macrophages and indicated an early intraparenchymal accumulation of thrombospondin following injury. These results suggest that brain macrophages contribute actively to neurite growth or regeneration during the development or in pathological contexts.

154 citations

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TL;DR: In this paper, the authors assessed parents' first concerns about their autistic child and categorized them into three groups: (a) early awareness group, which included motor problems and passivity (14.6 months); (b) intermediate awareness group including emotional, hyperactivity, and sleep problems (15.3 months); and (c) later awareness group which included communication problems, poor social interaction, and autistic type behaviors (22.3months).

135 citations


Cited by
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TL;DR: Reading a book as this basics of qualitative research grounded theory procedures and techniques and other references can enrich your life quality.

13,415 citations

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TL;DR: An understanding of intercellular signalling pathways for microglia proliferation and activation could form a rational basis for targeted intervention on glial reactions to injuries in the CNS.

4,372 citations

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TL;DR: A summary of molecules whose levels of expression differentiate activated from resting astrocytes is provided and it becomes apparent that reactive astroCytes may benefit the injured nervous system by participating in diverse biological processes.

1,467 citations

Journal ArticleDOI
01 May 2016-Autism
TL;DR: It is demonstrated that there is no single way of describing autism that is universally accepted and preferred by the UK’s autism community and that some disagreements appear deeply entrenched.
Abstract: Recent public discussions suggest that there is much disagreement about the way autism is and should be described. This study sought to elicit the views and preferences of UK autism community membe...

1,089 citations

Journal ArticleDOI
01 Jan 1993-Glia
TL;DR: Interference with the microglial activation or the productions of cytotoxic metabolites by microglia may offer new therapeutic opportunities for the prevention of neuronal cell death in CNS disease.
Abstract: The most characteristic property of microglia is their swift activation in response to neuronal stress and their capacity for site-directed phagocytosis. The transformation of microglia into intrinsic brain macrophages appears to be under strict control and takes place if neuronal and/or terminal degeneration occurs in response to nerve lesion. The differentiation of microglia into brain macrophages is accompanied by the release of several secretory products, e.g., proteinases, cytokines, reactive oxygen intermediates, and reactive nitrogen intermediates. Interference with the microglial activation or the productions of cytotoxic metabolites by microglia may thus offer new therapeutic opportunities for the prevention of neuronal cell death in CNS disease.

1,032 citations