80 research outputs found

    Troubling meanings of "family" for young people who have been in care: from policy to lived experience

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    This article seeks to trouble the concept of “family” for young people who have been in out-of-home care, by reflecting on the continuing significance (and troubles) of family relationships beyond childhood. The analysis draws on two cross-national studies in Europe: Beyond Contact, which examined policies and systems for work with families of children in care, and Against All Odds?, a qualitative longitudinal study of young adults who have been in care. Policy discourses that reify and instrumentalize the concept of family—for example, through the language of “contact,” “reunification,” and “permanence”—neglect the complex temporality of “family” for young people who have been in care, negotiated and practiced across time and in multiple (and changing) care contexts, and forming part of complex, dynamic and relational identities, and understandings of “belonging” for young adults who have been in care

    Silsesquioxane 3-n-Propylpyridinium chloride: a new polymer for the potentiometric analysis of Cr(VI) in electroplating and leather industry wastes

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    A new polymer, silsesquioxane 3-n-propylpyridinium chloride (SiPy+Cl-), was used in the preparation of an electrode. The polymer coated graphite rod ion selective electrode for Cr(VI) was constructed and evaluated for the determination of Cr(VI) in samples of electroplating and leather industry wastes. This electrode exhibited a Nernstian response for Cr(VI) concentrations between 3.1<FONT FACE=Symbol>&acute;</FONT>10-6 and 1.8<FONT FACE=Symbol>&acute;</FONT>10-2 mol L-1 and a detection limit of 2.8<FONT FACE=Symbol>&acute;</FONT>10-6 mol L-1 (0.15 ppm). The response of the electrode for Cr(VI) was fast (15 s) and the independent potential of pH in the range of 3.0 to 7.0. The selectivity coefficients for several anions showed that the electrode presents excellent performance. The sensor exhibits a shelf-life of 6 months with good reproducibility. Determination of Cr(VI) in electroplating and leather wastes using the sensor was successfully achieved

    Molecular Basis for Defining the Pineal Gland and Pinealocytes as Targets for Tumor Necrosis Factor

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    The pineal gland, the gland that translates darkness into an endocrine signal by releasing melatonin at night, is now considered a key player in the mounting of an innate immune response. Tumor necrosis factor (TNF), the first pro-inflammatory cytokine to be released by an inflammatory response, suppresses the translation of the key enzyme of melatonin synthesis (arylalkylamine-N-acetyltransferase, Aanat). Here, we show that TNF receptors of the subtype 1 (TNF-R1) are expressed by astrocytes, microglia, and pinealocytes. We also show that the TNF signaling reduces the level of inhibitory nuclear factor kappa B protein subtype A (NFKBIA), leading to the nuclear translocation of two NFKB dimers, p50/p50, and p50/RelA. The lack of a transactivating domain in the p50/p50 dimer suggests that this dimer is responsible for the repression of Aanat transcription. Meanwhile, p50/RelA promotes the expression of inducible nitric oxide synthase (iNOS) and the production of nitric oxide, which inhibits adrenergically induced melatonin production. Together, these data provide a mechanistic basis for considering pinealocytes a target of TNF and reinforce the idea that the suppression of pineal melatonin is one of the mechanisms involved in mounting an innate immune response

    Anti-IL-2 Treatment Impairs the Expansion of Treg Cell Population during Acute Malaria and Enhances the Th1 Cell Response at the Chronic Disease

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    Plasmodium chabaudi infection induces a rapid and intense splenic CD4+ T cell response that contributes to both disease pathogenesis and the control of acute parasitemia. The subsequent development of clinical immunity to disease occurs concomitantly with the persistence of low levels of chronic parasitemia. The suppressive activity of regulatory T (Treg) cells has been implicated in both development of clinical immunity and parasite persistence. To evaluate whether IL-2 is required to induce and to sustain the suppressive activity of Treg cells in malaria, we examined in detail the effects of anti-IL-2 treatment with JES6-1 monoclonal antibody (mAb) on the splenic CD4+ T cell response during acute and chronic P. chabaudi AS infection in C57BL/6 mice. JES6-1 treatment on days 0, 2 and 4 of infection partially inhibits the expansion of the CD4+CD25+Foxp3+ cell population during acute malaria. Despite the concomitant secretion of IL-2 and expression of high affinity IL-2 receptor by large CD4+ T cells, JES6-1 treatment does not impair effector CD4+ T cell activation and IFN-γ production. However, at the chronic phase of the disease, an enhancement of cellular and humoral responses occurs in JES6-1-treated mice, with increased production of TNF-α and parasite-specific IgG2a antibodies. Furthermore, JES6-1 mAb completely blocked the in vitro proliferation of CD4+ T cells from non-treated chronic mice, while it further increased the response of CD4+ T cells from JES6-1-treated chronic mice. We conclude that JES6-1 treatment impairs the expansion of Treg cell population during early P. chabaudi malaria and enhances the Th1 cell response in the late phase of the disease

    Ammonium ion sensor based on SiO2/ZrO2/phosphate-NH4+ composite for quantification of ammonium ions in natural waters

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    Ion selective-electrode was constructed and evaluated for determination of ammonium ions in natural waters. The electrode consists of paste carbon with the composite SiO2/ZrO2/phosphate-NH4+ obtained through sol-gel process. The electrode exhibits a sub-Nernstian response for ammonium concentrations between 7.7<FONT FACE=Symbol>&acute;</FONT>10-7 and 4.0<FONT FACE=Symbol>&acute;</FONT>10-2 mol L-1 and a detection limit of 1.58<FONT FACE=Symbol>&acute;</FONT>10-7 mol L-1 (8.5<FONT FACE=Symbol>&acute;</FONT>10-3 ppm). The electrode response for ammonium was fast (1 minute). The selectivity coefficients KpotA,B for several ions usually present in natural waters were determined applying the matched potential method. The potentiometric method with the ion selective electrode was validated by the Berthelot method (standard method), through the determination of ammonium ions in natural waters. The ion selective-electrode proved suitable for routine quality control of natural waters by potentiometry

    Leishmania amazonensis Arginase Compartmentalization in the Glycosome Is Important for Parasite Infectivity

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    In Leishmania, de novo polyamine synthesis is initiated by the cleavage of L-arginine to urea and L-ornithine by the action of arginase (ARG, E.C. 3.5.3.1). Previous studies in L. major and L. mexicana showed that ARG is essential for in vitro growth in the absence of polyamines and needed for full infectivity in animal infections. The ARG protein is normally found within the parasite glycosome, and here we examined whether this localization is required for survival and infectivity. First, the localization of L. amazonensis ARG in the glycosome was confirmed in both the promastigote and amastigote stages. As in other species, arg− L. amazonensis required putrescine for growth and presented an attenuated infectivity. Restoration of a wild type ARG to the arg− mutant restored ARG expression, growth and infectivity. In contrast, restoration of a cytosol-targeted ARG lacking the glycosomal SKL targeting sequence (argΔSKL) restored growth but failed to restore infectivity. Further study showed that the ARGΔSKL protein was found in the cytosol as expected, but at very low levels. Our results indicate that the proper compartmentalization of L. amazonensis arginase in the glycosome is important for enzyme activity and optimal infectivity. Our conjecture is that parasite arginase participates in a complex equilibrium that defines the fate of L-arginine and that its proper subcellular location may be essential for this physiological orchestration

    In Vivo Approaches Reveal a Key Role for DCs in CD4+ T Cell Activation and Parasite Clearance during the Acute Phase of Experimental Blood-Stage Malaria

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    Dendritic cells (DCs) are phagocytes that are highly specialized for antigen presentation. Heterogeneous populations of macrophages and DCs form a phagocyte network inside the red pulp (RP) of the spleen, which is a major site for the control of blood-borne infections such as malaria. However, the dynamics of splenic DCs during Plasmodium infections are poorly understood, limiting our knowledge regarding their protective role in malaria. Here, we used in vivo experimental approaches that enabled us to deplete or visualize DCs in order to clarify these issues. To elucidate the roles of DCs and marginal zone macrophages in the protection against blood-stage malaria, we infected DTx (diphtheria toxin)-treated C57BL/6.CD11c-DTR mice, as well as C57BL/6 mice treated with low doses of clodronate liposomes (ClLip), with Plasmodium chabaudi AS (Pc) parasites. The first evidence suggesting that DCs could contribute directly to parasite clearance was an early effect of the DTx treatment, but not of the ClLip treatment, in parasitemia control. DCs were also required for CD4+ T cell responses during infection. The phagocytosis of infected red blood cells (iRBCs) by splenic DCs was analyzed by confocal intravital microscopy, as well as by flow cytometry and immunofluorescence, at three distinct phases of Pc malaria: at the first encounter, at pre-crisis concomitant with parasitemia growth and at crisis when the parasitemia decline coincides with spleen closure. In vivo and ex vivo imaging of the spleen revealed that DCs actively phagocytize iRBCs and interact with CD4+ T cells both in T cell-rich areas and in the RP. Subcapsular RP DCs were highly efficient in the recognition and capture of iRBCs during pre-crisis, while complete DC maturation was only achieved during crisis. These findings indicate that, beyond their classical role in antigen presentation, DCs also contribute to the direct elimination of iRBCs during acute Plasmodium infection.São Paulo Research Foundation grants: (2011/24038-1 [MRDL], 2009/08559-1 [HBdS], CAPES/IGC 04/ 2012 [MRDL, CET])

    IFNγ and IL-12 restrict Th2 responses during Helminth/Plasmodium co-infection and promote IFNγ from Th2 cells

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    Parasitic helminths establish chronic infections in mammalian hosts. Helminth/Plasmodium co-infections occur frequently in endemic areas. However, it is unclear whether Plasmodium infections compromise anti-helminth immunity, contributing to the chronicity of infection. Immunity to Plasmodium or helminths requires divergent CD4+ T cell-driven responses, dominated by IFNγ or IL-4, respectively. Recent literature has indicated that Th cells, including Th2 cells, have phenotypic plasticity with the ability to produce non-lineage associated cytokines. Whether such plasticity occurs during co-infection is unclear. In this study, we observed reduced anti-helminth Th2 cell responses and compromised anti-helminth immunity during Heligmosomoides polygyrus and Plasmodium chabaudi co-infection. Using newly established triple cytokine reporter mice (Il4gfpIfngyfpIl17aFP635), we demonstrated that Il4gfp+ Th2 cells purified from in vitro cultures or isolated ex vivo from helminth-infected mice up-regulated IFNγ following adoptive transfer into Rag1-/- mice infected with P. chabaudi. Functionally, Th2 cells that up-regulated IFNγ were transcriptionally re-wired and protected recipient mice from high parasitemia. Mechanistically, TCR stimulation and responsiveness to IL-12 and IFNγ, but not type I IFN, was required for optimal IFNγ production by Th2 cells. Finally, blockade of IL-12 and IFNγ during co-infection partially preserved anti-helminth Th2 responses. In summary, this study demonstrates that Th2 cells retain substantial plasticity with the ability to produce IFNγ during Plasmodium infection. Consequently, co-infection with Plasmodium spp. may contribute to the chronicity of helminth infection by reducing anti-helminth Th2 cells and converting them into IFNγ-secreting cells
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