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1.
Global Health ; 14(1): 13, 2018 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-29378667

RESUMO

BACKGROUND: Grand Challenges for international health and development initiatives have received substantial funding to tackle unsolved problems; however, evidence of their effectiveness in achieving change is lacking. A theory of change may provide a useful tool to track progress towards desired outcomes. The Saving Lives at Birth partnership aims to address inequities in maternal-newborn survival through the provision of strategic investments for the development, testing and transition-to-scale of ground-breaking prevention and treatment approaches with the potential to leapfrog conventional healthcare approaches in low resource settings. We aimed to develop a theory of change and impact framework with prioritised metrics to map the initiative's contribution towards overall goals, and to measure progress towards improved outcomes around the time of birth. METHODS: A theory of change and impact framework was developed retrospectively, drawing on expertise across the partnership and stakeholders. This included a document and literature review, and wide consultation, with feedback from stakeholders at all stages. Possible indicators were reviewed from global maternal-newborn health-related partner initiatives, priority indicator lists, and project indicators from current innovators. These indicators were scored across five domains to prioritise those most relevant and feasible for Saving Lives at Birth. These results informed the identification of the prioritised metrics for the initiative. RESULTS: The pathway to scale through Saving Lives at Birth is articulated through a theory of change and impact framework, which also highlight the roles of different actors involved in the programme. A prioritised metrics toolkit, including ten core impact indicators and five additional process indicators, complement the theory of change. The retrospective nature of this development enabled structured reflection of the program mechanics, allowing for inclusion of learning from the first four rounds of the program to inform implementation of subsequent rounds. CONCLUSIONS: While theories of change are more traditionally developed before program implementation, retrospective development can still be a useful exercise for multi-round programs like Saving Lives at Birth, where outputs from the development can be used to strengthen subsequent rounds. However, identifying a uniform set of prioritised metrics for use across the portfolio proved more challenging. Lessons learnt from this exercise will be relevant to the development of pathways to change across other Grand Challenges and global health platforms.


Assuntos
Saúde Global , Promoção da Saúde , Saúde do Lactente , Saúde Materna , Avaliação de Programas e Projetos de Saúde/métodos , Feminino , Humanos , Lactente , Mortalidade Infantil/tendências , Recém-Nascido , Mortalidade Materna/tendências , Modelos Teóricos , Gravidez , Estudos Retrospectivos
2.
PLoS Pathog ; 11(9): e1005140, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26402732

RESUMO

The in utero environment profoundly impacts childhood neurodevelopment and behaviour. A substantial proportion of pregnancies in Africa are at risk of malaria in pregnancy (MIP) however the impact of in utero exposure to MIP on fetal neurodevelopment is unknown. Complement activation, in particular C5a, may contribute to neuropathology and adverse outcomes during MIP. We used an experimental model of MIP and standardized neurocognitive testing, MRI, micro-CT and HPLC analysis of neurotransmitter levels, to test the hypothesis that in utero exposure to malaria alters neurodevelopment through a C5a-C5aR dependent pathway. We show that malaria-exposed offspring have persistent neurocognitive deficits in memory and affective-like behaviour compared to unexposed controls. These deficits were associated with reduced regional brain levels of major biogenic amines and BDNF that were rescued by disruption of C5a-C5aR signaling using genetic and functional approaches. Our results demonstrate that experimental MIP induces neurocognitive deficits in offspring and suggest novel targets for intervention.


Assuntos
Complemento C5a/metabolismo , Interações Hospedeiro-Parasita , Malária/fisiopatologia , Transtornos Neurocognitivos/etiologia , Neurogênese , Complicações Parasitárias na Gravidez/fisiopatologia , Receptor da Anafilatoxina C5a/metabolismo , Animais , Aminas Biogênicas/metabolismo , Encéfalo/irrigação sanguínea , Encéfalo/imunologia , Encéfalo/metabolismo , Encéfalo/patologia , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Circulação Cerebrovascular , Regulação para Baixo , Feminino , Desenvolvimento Fetal , Malária/imunologia , Malária/metabolismo , Malária/parasitologia , Masculino , Camundongos Endogâmicos BALB C , Camundongos Knockout , Transtornos Neurocognitivos/imunologia , Transtornos Neurocognitivos/metabolismo , Transtornos Neurocognitivos/patologia , Neurônios/imunologia , Neurônios/metabolismo , Neurônios/patologia , Plasmodium berghei/imunologia , Plasmodium berghei/fisiologia , Gravidez , Complicações Parasitárias na Gravidez/imunologia , Complicações Parasitárias na Gravidez/metabolismo , Complicações Parasitárias na Gravidez/parasitologia , Receptor da Anafilatoxina C5a/genética , Transdução de Sinais
3.
J Pathol ; 233(1): 18-26, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24293254

RESUMO

The study of mutations causing the steroid-resistant nephrotic syndrome in children has greatly advanced our understanding of the kidney filtration barrier. In particular, these genetic variants have illuminated the roles of the podocyte, glomerular basement membrane and endothelial cell in glomerular filtration. However, in a significant number of familial and early onset cases, an underlying mutation cannot be identified, indicating that there are likely to be multiple unknown genes with roles in glomerular permeability. We now show how the combination of N-ethyl-N-nitrosourea mutagenesis and next-generation sequencing could be used to identify the range of mutations affecting these pathways. Using this approach, we isolated a novel mouse strain with a viable nephrotic phenotype and used whole-genome sequencing to isolate a causative hypomorphic mutation in Lamb2. This discovery generated a model for one part of the spectrum of human Pierson's syndrome and provides a powerful proof of principle for accelerating gene discovery and improving our understanding of inherited forms of renal disease.


Assuntos
Anormalidades Múltiplas/genética , Análise Mutacional de DNA/métodos , Anormalidades do Olho/genética , Sequenciamento de Nucleotídeos em Larga Escala , Laminina/genética , Mutação , Síndrome Nefrótica/congênito , Distúrbios Pupilares/genética , Anormalidades Múltiplas/metabolismo , Anormalidades Múltiplas/patologia , Animais , Modelos Animais de Doenças , Etilnitrosoureia , Anormalidades do Olho/metabolismo , Anormalidades do Olho/patologia , Estudos de Associação Genética , Predisposição Genética para Doença , Túbulos Renais/metabolismo , Túbulos Renais/patologia , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Síndromes Miastênicas Congênitas , Síndrome Nefrótica/genética , Síndrome Nefrótica/metabolismo , Síndrome Nefrótica/patologia , Linhagem , Fenótipo , Proteinúria/genética , Proteinúria/metabolismo , Distúrbios Pupilares/metabolismo , Distúrbios Pupilares/patologia
4.
Lancet ; 392(10162): 2350, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30527611
5.
Drug Metab Dispos ; 42(4): 603-10, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24281836

RESUMO

Preventing and treating malaria in pregnancy is a global health priority. However little is known regarding the impact of malaria infection on the maternal and fetal disposition of pharmaceuticals and other xenobiotics. Our objective was to characterize expression of key determinants of drug-disposition in maternal and fetal tissues in a validated murine model of experimental placental malaria. Balb/c mice were infected with Plasmodium berghei at mid gestation [gestational day (GD) 13] and maternal, placental, and fetal tissues were collected at GD19. Expression of key ABC drug transporters and Cyp3a11 was examined by quantitative polymerase chain reaction. Western blotting was used to examine the protein expression of multidrug resistance protein 1 (MDR1, ABCB1). Compared with controls, placental mRNA expression of Abcb1a, Abcb1b, Abcc1, Abcc2, Abcc3, and Abcg2 were significantly downregulated in the malaria-infected group (P < 0.05), as was placental MDR1 protein (P < 0.05). Significantly decreased hepatic expression of Abcc2, Abcg2, and Abcb11 and significantly increased expression of Abcb1b, Abcc1, and Abcc3 were seen in malaria-infected dams (P < 0.05) in comparison with uninfected controls. The expression of Abcb1a and Abcg2 was significantly decreased in fetal liver of infected dams, whereas levels of Abcb1b were increased (P < 0.05). Maternal and fetal hepatic expression of Cyp3a11 was significantly downregulated in the malaria group (P < 0.05). Together, malaria-induced alterations in the expression of transporters and drug-metabolizing enzymes in maternal and fetal tissues may alter the disposition of endogenous and therapeutic substrates, potentially impacting maternal and fetal outcomes.


Assuntos
Proteínas de Transporte/genética , Fígado/metabolismo , Malária/metabolismo , Preparações Farmacêuticas/metabolismo , Placenta/metabolismo , Complicações Parasitárias na Gravidez/metabolismo , Animais , Ácidos e Sais Biliares/sangue , Transporte Biológico , Proteínas de Transporte/metabolismo , Citocromo P-450 CYP3A/genética , Citocromo P-450 CYP3A/metabolismo , Modelos Animais de Doenças , Feminino , Fígado/embriologia , Malária/parasitologia , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Estresse Oxidativo , Plasmodium berghei/patogenicidade , Gravidez , Complicações Parasitárias na Gravidez/parasitologia , Distribuição Tecidual
6.
J Exp Med ; 204(4): 759-69, 2007 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-17420266

RESUMO

Immunological memory is characterized by heightened immunoglobulin (Ig) G antibody production caused in part by enhanced plasma cell formation conferred by conserved transmembrane and cytoplasmic segments in isotype-switched IgG B cell receptors. We tested the hypothesis that the IgG tail enhances intracellular B cell antigen receptor (BCR) signaling responses to antigen by analyzing B cells from Ig transgenic mice with IgM receptors or chimeric IgMG receptors containing the IgG tail segment. The IgG tail segment enhanced intracellular calcium responses but not tyrosine or extracellular signal-related kinase (ERK) phosphorylation. Biochemical analysis and crosses to CD22-deficient mice established that IgG tail enhancement of calcium and antibody responses, as well as marginal zone B cell formation, was not due to diminished CD22 phosphorylation or inhibitory function. Microarray profiling showed no evidence for enhanced signaling by the IgG tail for calcium/calcineurin, ERK, or nuclear factor kappaB response genes and little evidence for any enhanced gene induction. Instead, almost half of the antigen-induced gene response in IgM B cells was diminished 50-90% by the IgG tail segment. These findings suggest a novel "less-is-more" hypothesis to explain how switching to IgG enhances B cell memory responses, whereby decreased BCR signaling to genes that oppose marginal zone and plasma cell differentiation enhances the formation of these key cell types.


Assuntos
Sequência Conservada , Memória Imunológica/imunologia , Receptores de Antígenos de Linfócitos B/química , Receptores de Antígenos de Linfócitos B/metabolismo , Receptores de IgG/química , Receptores de IgG/metabolismo , Transdução de Sinais , Animais , Linfócitos B/citologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Cálcio/metabolismo , Diferenciação Celular , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Imunoglobulina M/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosfotirosina/metabolismo , Receptores de Antígenos de Linfócitos B/genética , Receptores de Antígenos de Linfócitos B/imunologia , Receptores de IgG/genética , Receptores de IgG/imunologia , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico/genética , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico/metabolismo , Transdução de Sinais/imunologia , Ativação Transcricional
7.
Cell Microbiol ; 12(8): 1036-45, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20545944

RESUMO

Severe malaria remains a major cause of global mortality. The innate immune response to infection is a key determinant of malaria severity and outcome. The complement system plays a key role in initiating and augmenting innate immune responses, including inflammation, endothelial activation, opsonization and coagulation, processes which have been implicated in malaria pathogenesis. In this review, we discuss the evidence supporting a role for excessive complement activation in the pathogenesis of severe malaria.


Assuntos
Proteínas do Sistema Complemento/imunologia , Imunidade Inata , Malária/imunologia , Malária/patologia , Plasmodium/imunologia , Animais , Humanos
9.
BMJ Open ; 10(4): e032134, 2020 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-32341042

RESUMO

OBJECTIVE: The WHO recommends responsive caregiving and early learning (RCEL) interventions to improve early child development (ECD), and to achieve the Sustainable Development Goals' vision of a world where all children thrive. Implementation of RCEL programmes in low and middle-income countries (LMIC) requires evidence to inform decisions about human resources and curricula content. We aimed to describe human resources and curricula content for implementation of RCEL projects across diverse LMICs, using data from the Grand Challenges Canada Saving Brains ECD portfolio. SETTING: We evaluated 32 RCEL projects across 17 LMICs on four continents. PARTICIPANTS: Overall, 2165 workers delivered ECD interventions to 25 909 families. INTERVENTION: Projects were either stand-alone RCEL or RCEL combined with health and nutrition, and/or safety and security. PRIMARY AND SECONDARY OUTCOMES: We undertook a mixed methods evaluation of RCEL projects within the Saving Brains portfolio. Quantitative data were collected through standardised reporting tools. Qualitative data were collected from ECD experts and stakeholders and analysed using thematic content analysis, informed by literature review. RESULTS: Major themes regarding human resources included: worker characteristics, incentivisation, retention, training and supervision, and regarding curricula content: flexible adaptation of content and delivery, fidelity, and intervention duration and dosage. Lack of an agreed standard ECD package contributed to project heterogeneity. Incorporation of ECD into existing services may facilitate scale-up but overburdened workers plus potential reductions in service quality remain challenging. Supportive training and supervision, inducement, worker retention, dosage and delivery modality emerged as key implementation decisions. CONCLUSIONS: This mixed methods evaluation of a multicountry ECD portfolio identified themes for consideration by policymakers and programme leaders relevant to RCEL implementation in diverse LMICs. Larger studies, which also examine impact, including high-quality process and costing evaluations with comparable data, are required to further inform decisions for implementation of RCEL projects at national and regional scales.


Assuntos
Desenvolvimento Infantil , Currículo , Países em Desenvolvimento , Desenvolvimento Sustentável , Recursos Humanos/estatística & dados numéricos , Criança , Humanos , Pesquisa Qualitativa
10.
Arch Dis Child ; 104(Suppl 1): S43-S50, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30885965

RESUMO

The Sustainable Development Goals, Global Strategy for Women's, Children's and Adolescents' Health (2016-2030) and Nurturing Care Framework all include targets to ensure children thrive However, many projects to support early childhood development (ECD) do not 'scale well' and leave large numbers of children unreached. This paper is the fifth in a series examining effective scaling of ECD programmes. This qualitative study explored experiences of scaling-up among purposively recruited implementers of ECD projects in low- and middle-income countries. Participants were sampled, by means of snowball sampling, from existing networks notably through Saving Brains®, Grand Challenges Canada®. Findings of a recent literature review on scaling-up frameworks, by the WHO, informed the development of a semistructured interview schedule. All interviews were conducted in English, via Skype, audio recorded and transcribed verbatim. Interviews were analysed using framework analysis. Framework analysis identified six major themes based on a standard programme cycle: planning and strategic choices, project design, human resources, financing and resource mobilisation, monitoring and evaluation, and leadership and partnerships. Key informants also identified an overarching theme regarding what scaling-up means. Stakeholders have not found existing literature and available frameworks helpful in guiding them to successful scale-up. Our research suggests that rather than proposing yet more theoretical guidelines or frameworks, it would be better to support stakeholders in developing organisational leadership capacity and partnership strategies to enable them to effectively apply a practical programme cycle or systematic process in their own contexts.


Assuntos
Desenvolvimento Infantil , Serviços de Saúde da Criança/organização & administração , Criança , Saúde da Criança , Países em Desenvolvimento , Política de Saúde , Humanos , Liderança , Desenvolvimento de Programas , Avaliação de Programas e Projetos de Saúde
11.
Arch Dis Child ; 104(Suppl 1): S3-S12, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30885961

RESUMO

Translating the Nurturing Care Framework and unprecedented global policy support for early child development (ECD) into action requires evidence-informed guidance about how to implement ECD programmes at national and regional scale. We completed a literature review and participatory mixed-method evaluation of projects in Saving Brains®, Grand Challenges Canada® funded ECD portfolio across 23 low- and middle-income countries (LMIC). Using an adapted programme cycle, findings from evaluation related to partnerships and leadership, situational analyses, and design for scaling ECD were considered. 39 projects (5 'Transition to Scale' and 34 'Seed') were evaluated. 63% were delivered through health and 84% focused on Responsive Caregiving and Early Learning (RCEL). Multilevel partnerships, leadership and targeted situational analysis were crucial to design and adaptation. A theory of change approach to consider pathways to impact was useful for design, but practical situational analysis tools and local data to guide these processes were lacking. Several RCEL programmes, implemented within government services, had positive impacts on ECD outcomes and created more enabling caregiving environments. Engagement of informal and private sectors provided an alternative approach for reaching children where government services were sparse. Cost-effectiveness was infrequently measured. At small-scale RCEL interventions can be successfully adapted and implemented across diverse settings through processes which are responsive to situational analysis within a partnership model. Accelerating progress will require longitudinal evaluation of ECD interventions at much larger scale, including programmes targeting children with disabilities and humanitarian settings with further exploration of cost-effectiveness, critical content and human resources.


Assuntos
Desenvolvimento Infantil , Serviços de Saúde da Criança/organização & administração , Criança , Pré-Escolar , Países em Desenvolvimento , Política de Saúde , Humanos , Lactente , Recém-Nascido , Relações Interinstitucionais
12.
Ann N Y Acad Sci ; 1419(1): 230-248, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29791735

RESUMO

Small pilot studies of young children have frequently shown promise, but very few have been successfully scaled to the regional or national levels. How can we ensure that these promising approaches move from a suite of pilots to full-scale implementation that can deliver sustainable impact for hundreds of millions of children? To elucidate concrete lessons learned and suggestions on accelerating the transition to impact at scale, we reviewed the Saving Brains portfolio to better understand three points: (1) the extent to which useful signals of impact could be extracted from data at the seed phase, (2) the ways in which innovators (project leaders) were approaching human resource challenges critical for scaling, and (3) the multisector diversity of the portfolio and the way innovators entered partnerships. The findings suggest key considerations for transitioning early childhood development interventions to scale and sustainability: strong entrepreneurial leadership, rigorous measurement and active use of data in support of adaptive learning, and champions acting at subnational levels. Together, these can enable flexible, iterative learning that can make the scaling process an opportunity to increase the level of benefit each child receives from an intervention.


Assuntos
Desenvolvimento Infantil , Intervenção Educacional Precoce , Criança , Pré-Escolar , Empreendedorismo , Humanos , Liderança , Projetos Piloto , Desenvolvimento de Programas
13.
J Glob Health ; 7(1): 011002, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28685048

RESUMO

BACKGROUND: Existing health and nutrition services present potential platforms for scaling up delivery of early childhood development (ECD) interventions within sensitive windows across the life course, especially in the first 1000 days from conception to age 2 years. However, there is insufficient knowledge on how to optimize implementation for such strategies in an integrated manner. In light of this knowledge gap, we aimed to systematically identify a set of integrated implementation research priorities for health, nutrition and early child development within the 2015 to 2030 timeframe of the Sustainable Development Goals (SDGs). METHODS: We applied the Child Health and Nutrition Research Initiative method, and consulted a diverse group of global health experts to develop and score 57 research questions against five criteria: answerability, effectiveness, deliverability, impact, and effect on equity. These questions were ranked using a research priority score, and the average expert agreement score was calculated for each question. FINDINGS: The research priority scores ranged from 61.01 to 93.52, with a median of 82.87. The average expert agreement scores ranged from 0.50 to 0.90, with a median of 0.75. The top-ranked research question were: i) "How can interventions and packages to reduce neonatal mortality be expanded to include ECD and stimulation interventions?"; ii) "How does the integration of ECD and MNCAH&N interventions affect human resource requirements and capacity development in resource-poor settings?"; and iii) "How can integrated interventions be tailored to vulnerable refugee and migrant populations to protect against poor ECD and MNCAH&N outcomes?". Most highly-ranked research priorities varied across the life course and highlighted key aspects of scaling up coverage of integrated interventions in resource-limited settings, including: workforce and capacity development, cost-effectiveness and strategies to reduce financial barriers, and quality assessment of programs. CONCLUSIONS: Investing in ECD is critical to achieving several of the SDGs, including SDG 2 on ending all forms of malnutrition, SDG 3 on ensuring health and well-being for all, and SDG 4 on ensuring inclusive and equitable quality education and promotion of life-long learning opportunities for all. The generated research agenda is expected to drive action and investment on priority approaches to integrating ECD interventions within existing health and nutrition services.


Assuntos
Prestação Integrada de Cuidados de Saúde/organização & administração , Serviços de Saúde Materno-Infantil/organização & administração , Pesquisa , Adolescente , Criança , Desenvolvimento Infantil , Pré-Escolar , Feminino , Saúde Global , Humanos , Lactente , Recém-Nascido , Estado Nutricional , Gravidez
14.
Transplantation ; 81(3): 308-15, 2006 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-16477212

RESUMO

Autoreactive B cells are actively tolerized to more abundant self-antigens by a series of checkpoints involving receptor editing, deletion, anergy and competition for growth factors. In contrast, B cells reactive against rare, sequestered or tissue specific self-antigens remain functionally naïve. During an immune response, the autoimmune danger from these cells is countered by a variety of mechanisms comprising control of self-antigen presentation, limitation of immunogenic and tolerogenic costimuli including T cell help, homeostatic control of growth and strict regulation of germinal centre reactions. In this overview we consider how knowledge of these checkpoints may be used to gain a better understanding of transplant tolerance and the generation of alloantibodies.


Assuntos
Autoantígenos/imunologia , Autoimunidade , Linfócitos B/imunologia , Imunologia de Transplantes , Tolerância ao Transplante , Anergia Clonal , Humanos , Linfócitos T Auxiliares-Indutores/imunologia
15.
Sci Transl Med ; 8(358): 358ra128, 2016 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-27683553

RESUMO

Cerebral malaria is a leading cause of global morbidity and mortality. Interventions targeting the underlying pathophysiology of cerebral malaria may improve outcomes compared to treatment with antimalarials alone. Microvascular leak plays an important role in the pathogenesis of cerebral malaria. The angiopoietin (Ang)-Tie-2 system is a critical regulator of vascular function. We show that Ang-1 expression and soluble Tie-2 expression were associated with disease severity and outcome in a prospective study of Ugandan children with severe malaria and in a preclinical murine model of experimental cerebral malaria. Ang-1 was necessary for maintenance of vascular integrity and survival in a mouse model of cerebral malaria. Therapeutic administration of Ang-1 preserved blood-brain barrier integrity and, in combination with artesunate treatment, improved survival beyond that with artesunate alone. These data define a role for dysregulation of the Ang-Tie-2 axis in the pathogenesis of cerebral malaria and support the evaluation of Ang-Tie-2-based interventions as potential adjunctive therapies for treating severe malaria.


Assuntos
Angiopoietina-1/metabolismo , Malária Cerebral/etiologia , Malária Cerebral/metabolismo , Adenoviridae/metabolismo , Animais , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Artemisininas/farmacologia , Artemisininas/uso terapêutico , Artesunato , Barreira Hematoencefálica/patologia , Pré-Escolar , Modelos Animais de Doenças , Suscetibilidade a Doenças , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/patologia , Feminino , Deleção de Genes , Humanos , Lactente , Estimativa de Kaplan-Meier , Cinética , Malária Falciparum/metabolismo , Malária Falciparum/patologia , Masculino , Camundongos Endogâmicos C57BL , Fenótipo , Plasmodium falciparum/efeitos dos fármacos , Receptor TIE-2/metabolismo , Proteínas Recombinantes/farmacologia , Análise de Sobrevida , Resultado do Tratamento , Uganda
16.
Sci STKE ; 2003(184): pe21, 2003 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-12771436

RESUMO

The B cell receptor (BCR) consists of an antigen-binding membrane immunoglobulin (mIg) associated with the CD79alpha and CD79beta heterodimer. Naïve B cells express the IgM and IgD isotypes, which have very short cytoplasmic tails and therefore depend on CD79alpha and CD79beta for signal transduction. After antigenic stimulation, B cells undergo isotype switching to yield IgG, IgE, or IgA. Recent research suggests that the ability of the B cell coreceptor CD22 to regulate BCR signaling depends on the isotype of the mIg cytoplasmic tail. Cell lines that express a BCR with the cytoplasmic tail from IgG, the isotype found in memory B cells, are not subject to CD22 regulation, whereas cell lines that express BCRs with IgM cytoplasmic tails are subject to CD22 regulation. Moreover, stimulation through BCRs containing an IgG cytoplasmic tail causes increased numbers of antigen-specific clones to accumulate. These observations are a valuable step toward understanding the difference in B cell signaling between na ve and memory cells. Here, we discuss the implications of these findings for CD22 regulation and signaling through the mIgG-containing BCR.


Assuntos
Subpopulações de Linfócitos B/imunologia , Isotipos de Imunoglobulinas/fisiologia , Transdução de Sinais/imunologia , Humanos
17.
Cell Host Microbe ; 13(2): 215-26, 2013 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-23414761

RESUMO

Placental malaria (PM) is a major cause of fetal growth restriction, yet the underlying mechanism is unclear. Complement C5a and C5a receptor levels are increased with PM. C5a is implicated in fetal growth restriction in non-infection-based animal models. In a case-control study of 492 pregnant Malawian women, we find that elevated C5a levels are associated with an increased risk of delivering a small-for-gestational-age infant. C5a was significantly increased in PM and was negatively correlated with the angiogenic factor angiopoietin-1 and positively correlated with angiopoietin-2, soluble endoglin, and vascular endothelial growth factor. Genetic or pharmacological blockade of C5a or its receptor in a mouse model of PM resulted in greater fetoplacental vessel development, reduced placental vascular resistance, and improved fetal growth and survival. These data suggest that C5a drives fetal growth restriction in PM through dysregulation of angiogenic factors essential for placental vascular remodeling resulting in placental vascular insufficiency.


Assuntos
Ativação do Complemento , Complemento C5a/metabolismo , Retardo do Crescimento Fetal/patologia , Regulação da Expressão Gênica no Desenvolvimento , Malária/patologia , Insuficiência Placentária/patologia , Complicações Parasitárias na Gravidez/patologia , Adolescente , Animais , Biomarcadores/metabolismo , Estudos de Casos e Controles , Modelos Animais de Doenças , Feminino , Retardo do Crescimento Fetal/metabolismo , Retardo do Crescimento Fetal/parasitologia , Idade Gestacional , Humanos , Malária/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Neovascularização Patológica/metabolismo , Placenta/irrigação sanguínea , Placenta/parasitologia , Insuficiência Placentária/metabolismo , Insuficiência Placentária/parasitologia , Plasmodium berghei/patogenicidade , Gravidez , Receptor da Anafilatoxina C5a , Receptores de Complemento/metabolismo , Transdução de Sinais , Transcrição Gênica , Adulto Jovem
20.
Trends Parasitol ; 27(7): 294-9, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21493146

RESUMO

Malaria infection is a significant risk factor for low birth weight outcomes in pregnancy. Despite efforts to define the molecular mechanisms that cause low birth weight as a result of intrauterine growth restriction, the roles of inflammation and mononuclear cells in the process are incompletely understood. Data from adverse pregnancy outcomes in humans and from murine models of pathological pregnancies suggest that C5a could be an important upstream regulator of placental angiogenesis, and excessive C5a could lead to functional placental insufficiency by impairing adequate vascularization of the placenta. Based on recent evidence, we hypothesize that complement factor C5a is a central initiator of poor birth outcomes associated with placental malaria by promoting mononuclear cell migration, activation and dysregulated angiogenesis.


Assuntos
Ativação do Complemento/imunologia , Placenta/parasitologia , Complicações Parasitárias na Gravidez/metabolismo , Resultado da Gravidez , Complemento C5a/genética , Complemento C5a/metabolismo , Feminino , Regulação da Expressão Gênica/imunologia , Humanos , Placenta/imunologia , Gravidez
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