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1.
Rheumatology (Oxford) ; 60(8): 3579-3587, 2021 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-33374013

RESUMO

OBJECTIVES: To evaluate the reliability of the OMERACT paediatric ultrasound (US) synovitis definitions and scoring system in JIA. METHODS: Thirteen sonographers analysed 75 images for the presence/absence of elementary lesions (binary scoring) and for grading synovitis, synovial hypertrophy, effusion and Doppler signals. Static US images of the second metacarpophalangeal joint (MCP-II), wrist, elbow, knee and ankle in JIA patients at different ages and different disease stages were collected with standardized scanning by two experienced sonographers. Intra- and inter-reader reliability were analysed with kappa coefficients. RESULTS: Intra-reader reliability was good for binary scoring (Cohen's kappa 0.62, range 0.47-0.75), synovitis and synovial hypertrophy; excellent for Doppler signals (quadratic weighted kappa 0.77, 0.66-0.86; 0.76, 0.61-0.84; and 0.87, 0.77-0.94, respectively); and moderate for effusion (0.55, 0.24-0.76). Inter-reader reliability was good for synovitis and synovial hypertrophy (Light's kappa 0.68, 95% CI: 0.61, 0.75 and 0.63, 0.54-0.71, respectively), excellent for Doppler signals (0.85, 95% CI: 0.77, 0.90), and moderate for binary scoring and effusion (0.48, 95% CI: 0.36, 0.64 and 0.49, 0.40-0.60, respectively). We obtained the best scores for the knee (0.71, 0.54-0.85) except for Doppler signals, with reliability higher for MCP-II. We found a trend toward better results in older children. CONCLUSIONS: This is the first study establishing the reliability of the OMERACT paediatric US synovitis definitions and scoring system in the five most commonly affected joints in JIA. The reliability was good among a large group of sonographers. These results support the applicability of these definitions and scoring system in clinical practice and multicentre studies.


Assuntos
Artrite Juvenil/diagnóstico por imagem , Articulações/diagnóstico por imagem , Sinovite/diagnóstico por imagem , Ultrassonografia/métodos , Humanos , Reprodutibilidade dos Testes , Índice de Gravidade de Doença
2.
Lancet ; 392(10163): 2452-2464, 2018 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-30473366

RESUMO

BACKGROUND: Bullying, aggression, and violence among children and young people are some of the most consequential public mental health problems. We tested the Learning Together intervention, which involved students in efforts to modify their school environment using restorative practice and by developing social and emotional skills. METHODS: We did a cluster randomised trial, with economic and process evaluations, of the Learning Together intervention compared with standard practice (controls) over 3 years in secondary schools in south-east England. Learning Together consisted of staff training in restorative practice; convening and facilitating a school action group; and a student social and emotional skills curriculum. Primary outcomes were self-reported experience of bullying victimisation (Gatehouse Bullying Scale; GBS) and perpetration of aggression (Edinburgh Study of Youth Transitions and Crime (ESYTC) school misbehaviour subscale) measured at 36 months. We analysed data using intention-to-treat longitudinal mixed-effects models. This trial was registered with the ISRCTN registry (10751359). FINDINGS: We included 40 schools (20 in each group); no schools withdrew. 6667 (93·6%) of 7121 students participated at baseline and 5960 (83·3%) of 7154 at 36 months. Mean GBS bullying score at 36 months was 0·34 (SE 0·02) in the control group versus 0·29 (SE 0·02) in the intervention group, with a significant adjusted mean difference (-0·03, 95% CI -0·06 to -0·001; adjusted effect size -0·08). Mean ESYTC score at 36 months was 4·33 (SE 0·20) in the control group versus 4·04 (0·21) in the intervention group, with no evidence of a difference between groups (adjusted difference -0·13, 95% CI -0·43 to 0·18; adjusted effect size -0·03). Costs were an additional £58 per pupil in intervention schools than in control schools. INTERPRETATION: Learning Together had small but significant effects on bullying, which could be important for public health, but no effect on aggression. Interventions to promote student health by modifying the whole-school environment are likely to be one of the most feasible and efficient ways of addressing closely related risk and health outcomes in children and young people. FUNDING: National Institute for Health Research, Educational Endowment Foundation.


Assuntos
Comportamento do Adolescente , Agressão/psicologia , Bullying/prevenção & controle , Aprendizado Social , Estudantes/psicologia , Violência/prevenção & controle , Adolescente , Criança , Currículo , Emoções , Inglaterra , Feminino , Humanos , Masculino , Instituições Acadêmicas , Habilidades Sociais , Apoio Social
3.
J Sch Health ; 89(12): 977-993, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31691287

RESUMO

BACKGROUND: Teachers report higher levels of stress than most occupational groups. Burnout is a specific psychological condition that results from chronic job stress characterized by emotional exhaustion, low personal accomplishment, and depersonalization. This study considers associations between aspects of the school environment and teacher burnout. METHODS: Exploratory analysis of baseline data from a cluster randomized controlled trial of 40 schools and 2278 teachers in the United Kingdom. Multilevel methods were used to consider the associations between different compositional and contextual aspects of the school environment and teacher burnout. RESULTS: There was evidence for school effects on teacher burnout, evidenced by ICCs and likelihood ratio tests, supporting the association between school environment and teacher burnout. The factors most consistently associated with teacher burnout in our study were teachers' perceptions of the school's safety and support and student attitudes to learning. CONCLUSIONS: The school environment does influence teacher burnout. More research is needed to develop and test causal pathways between the school environment and teacher burnout, and to understand ecological and individual predictors of teacher burnout and the interaction between the two.


Assuntos
Esgotamento Profissional/etiologia , Professores Escolares/psicologia , Instituições Acadêmicas , Esgotamento Profissional/diagnóstico , Feminino , Humanos , Masculino , Estresse Psicológico , Inquéritos e Questionários , Reino Unido
4.
J Epidemiol Community Health ; 73(6): 502-508, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30798267

RESUMO

BACKGROUND: The theory of human functioning and school organisation proposes that schools with rigid 'boundaries' (weaker relationships), for example, between staff and students, or learning and broader development, engender weaker student school commitment and sense of belonging, particularly among disadvantaged students, leading to greater involvement in risk-behaviours. Existing studies provide some support but rely on a proxy exposure of 'value-added education' and have not explored effects by disadvantage. METHODS: We used longitudinal data from English secondary schools from the control arm of a trial, assessing school-level measures of rigid boundaries, and student commitment and belonging at age 11/12, and student risk-behaviours at age 14/15. RESULTS: Our direct measures were more strongly associated with risk-behaviours than was value-added education. School-level rigid boundaries were associated with increased alcohol use and bullying. Student belonging was more consistently associated with reduced risk-behaviours than was student commitment. Some school effects were greater for students from disadvantaged subgroups defined in terms of poverty, ethnicity and family structure. CONCLUSION: Our results provide direct support for the theory of human functioning and school organisation and suggest a sense of belonging in school might be particularly protective factor among secondary school students. School effects on risk are generally stronger among disadvantaged students as theorised. TRIAL REGISTRATION NUMBER: ISRCTN10751359.


Assuntos
Consumo de Bebidas Alcoólicas/psicologia , Bullying/psicologia , Assunção de Riscos , Professores Escolares , Meio Social , Estudantes/psicologia , Adolescente , Comportamento do Adolescente , Consumo de Bebidas Alcoólicas/epidemiologia , Bullying/estatística & dados numéricos , Criança , Meio Ambiente , Feminino , Humanos , Relações Interpessoais , Masculino , Instituições Acadêmicas , Inquéritos e Questionários
5.
J Epidemiol Community Health ; 73(5): 455-464, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30723088

RESUMO

BACKGROUND: Interventions to modify school environments are effective in promoting young people's health across outcomes, but mechanisms are poorly understood. We assessed mediation in a trial of the Learning Together intervention, building on the recent publication of results of effectiveness for reducing bullying and benefits across secondary outcomes and generally good implementation fidelity. METHODS: Within a cluster-randomised trial involving 40 English schools, we examined student-reported and staff-reported school climate and student-reported involvement with delinquent peers at 24-month and 36-month follow-up, assessing the reliability of measures and whether these mediated health outcomes at a final follow-up. RESULTS: Response rates and reliability were good for student-reported but not staff-reported measures. The intervention increased student-reported but not staff-reported-positive school climate but, like effects on student health outcomes, these manifested only at a final follow-up. The intervention reduced student-reported contact with delinquent peers at an interim follow-up. Student-reported potential mediators measured at the interim follow-up were associated with most health outcomes at the final follow-up. Adjustment for student-reported school climate and contact with delinquent peers at the interim follow-up did not reduce the associations between trial arm and our health outcomes. CONCLUSION: Despite being constrained by imperfect measures and by the late manifestation of impacts on student-reported school climate undermining ability to assess mediation, our study for the first time provides tentative evidence that mediation of intervention effects via improved climate and disengagement from delinquent peers is plausible. Our study provides the first evidence from a trial that whole-school interventions may work by modifying school environments and student relationships. TRIAL REGISTRATION NUMBER: ISRCTN10751359.


Assuntos
Promoção da Saúde/métodos , Instituições Acadêmicas , Meio Social , Estudantes/psicologia , Adolescente , Bullying/prevenção & controle , Criança , Análise por Conglomerados , Inglaterra , Feminino , Humanos , Masculino , Autorrelato
6.
BMJ Open ; 8(2): e018640, 2018 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-29449292

RESUMO

OBJECTIVE: To undertake a cost-utility analysis of a motivational multicomponent lifestyle-modification intervention in a community setting (the Healthy Eating Lifestyle Programme (HELP)) compared with enhanced standard care. DESIGN: Cost-utility analysis alongside a randomised controlled trial. SETTING: Community settings in Greater London, England. PARTICIPANTS: 174 young people with obesity aged 12-19 years. INTERVENTIONS: Intervention participants received 12 one-to-one sessions across 6 months, addressing lifestyle behaviours and focusing on motivation to change and self-esteem rather than weight change, delivered by trained graduate health workers in community settings. Control participants received a single 1-hour one-to-one nurse-delivered session providing didactic weight-management advice. MAIN OUTCOME MEASURES: Mean costs and quality-adjusted life years (QALYs) per participant over a 1-year period using resource use data and utility values collected during the trial. Incremental cost-effectiveness ratio (ICER) was calculated and non-parametric bootstrapping was conducted to generate a cost-effectiveness acceptability curve (CEAC). RESULTS: Mean intervention costs per participant were £918 for HELP and £68 for enhanced standard care. There were no significant differences between the two groups in mean resource use per participant for any type of healthcare contact. Adjusted costs were significantly higher in the intervention group (mean incremental costs for HELP vs enhanced standard care £1003 (95% CI £837 to £1168)). There were no differences in adjusted QALYs between groups (mean QALYs gained 0.008 (95% CI -0.031 to 0.046)). The ICER of the HELP versus enhanced standard care was £120 630 per QALY gained. The CEAC shows that the probability that HELP was cost-effective relative to the enhanced standard care was 0.002 or 0.046, at a threshold of £20 000 or £30 000 per QALY gained. CONCLUSIONS: We did not find evidence that HELP was more effective than a single educational session in improving quality of life in a sample of adolescents with obesity. HELP was associated with higher costs, mainly due to the extra costs of delivering the intervention and therefore is not cost-effective. TRIAL REGISTRATION NUMBER: ISRCTN9984011.


Assuntos
Análise Custo-Benefício , Promoção da Saúde/métodos , Estilo de Vida Saudável , Motivação , Obesidade/terapia , Anos de Vida Ajustados por Qualidade de Vida , Padrão de Cuidado , Adolescente , Adulto , Peso Corporal , Criança , Custos e Análise de Custo , Dieta Saudável , Feminino , Educação em Saúde , Promoção da Saúde/economia , Humanos , Londres , Masculino , Obesidade/psicologia , Obesidade Infantil/psicologia , Obesidade Infantil/terapia , Características de Residência , Autoimagem , Redução de Peso , Adulto Jovem
7.
Trials ; 18(1): 238, 2017 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-28545574

RESUMO

BACKGROUND: Systematic reviews suggest that multi-component interventions are effective in reducing bullying victimisation and perpetration. We are undertaking a phase III randomised trial of the INCLUSIVE multi-component intervention. This trial aims to assess the effectiveness and cost-effectiveness of the INCLUSIVE intervention in reducing aggression and bullying victimisation in English secondary schools. This paper updates the original trial protocol published in 2014 (Trials 15:381, 2014) and presents the changes in the process evaluation protocol and the secondary outcome data collection. METHODS: The methods are summarised as follows. DESIGN: cluster randomised trial. PARTICIPANTS: 40 state secondary schools. Outcomes assessed among the cohort of students at the end of year 7 (n = 6667) at baseline. INTERVENTION: INCLUSIVE is a multi-component school intervention including a social and emotional learning curriculum, changes to school environment (an action group comprising staff and students reviews local data on needs to review rules and policies and determine other local actions) and staff training in restorative practice. The intervention will be delivered by schools supported in the first two years by educational facilitators independent of the research team, with a third intervention year involving no external facilitation but all other elements. Comparator: normal practice. OUTCOMES: Primary: Two primary outcomes at student level assessed at baseline and at 36 months: 1. Aggressive behaviours in school: Edinburgh Study of Youth Transitions and Crime school misbehaviour subscale (ESYTC) 2. Bullying and victimisation: Gatehouse Bullying Scale (GBS) Secondary outcomes assessed at baseline, 24 and 36 months will include measures relating to the economic evaluation, psychosocial outcomes in students and staff and school-level truancy and exclusion rates. SAMPLE SIZE: 20 schools per arm will provide 90% power to identify an effect size of 0.25 SD with a 5% significance level. Randomisation: eligible consenting schools were randomised stratified for single-sex versus mixed-sex schools, school-level deprivation and measures of school attainment. DISCUSSION: The trial involves independent research and intervention teams and is supervised by a Trial Steering Committee and a Data Monitoring Committee. TRIAL REGISTRATION: Current Controlled Trials, ISRCTN10751359 . Registered on 11 March 2014.


Assuntos
Comportamento do Adolescente , Agressão , Bullying/prevenção & controle , Meio Ambiente , Serviços de Saúde Escolar , Instituições Acadêmicas , Estudantes/psicologia , Adolescente , Fatores Etários , Análise Custo-Benefício , Emoções , Inglaterra , Humanos , Aprendizagem , Projetos de Pesquisa , Serviços de Saúde Escolar/economia , Instituições Acadêmicas/economia , Comportamento Social , Fatores de Tempo
8.
Arch Dis Child ; 102(8): 695-701, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28687677

RESUMO

OBJECTIVE: Approximately 7% of children and young people aged 5-15 years in the UK have obesity at a level likely to be associated with comorbidities. The majority of multicomponent lifestyle programmes have limited applicability and generalisability for British adolescents.The Healthy Eating and Lifestyle Programme (HELP) was a specific adolescent-focused intervention, designed for obese 12 to 18-year-olds seeking help to manage their weight. Participants were randomised to the 12-session HELP intervention or standard care. The primary outcome was difference in mean body mass index (BMI) (kg/m2) between groups at week 26 adjusted for baseline BMI, age and sex. SUBJECTS: 174 subjects were randomised (87 in each arm), of whom 145 (83%) provided primary outcome data at week 26. RESULTS: At week 26 there were no significant effects of the intervention on BMI (mean change in BMI 0.18 kg/m2 for the intervention arm, 0.25 kg/m2 for the control arm; adjusted difference between groups: -0.11 kg/m2 (95% CI -0.62 to 0.40), p=0.7). At weeks 26 and 52 there were no significant differences between groups in any secondary outcomes. CONCLUSION: At minimum this study reinforces the need for higher level, structured interventions to tackle the growing public health burden of obesity in the UK and internationally.The HELP intervention was no more effective than a single educational session for reducing BMI in a community sample of obese adolescents.Further work is needed to understand how weight management programmes can be delivered effectively to young people from diverse and deprived backgrounds in which childhood obesity is common. The study has significant implications in terms of informing public health interventions to tackle childhood obesity. TRIAL REGISTRATION NUMBER: ISRCTN: ISRCTN99840111.


Assuntos
Estilo de Vida Saudável , Entrevista Motivacional/métodos , Obesidade Infantil/prevenção & controle , Adolescente , Índice de Massa Corporal , Serviços de Saúde Comunitária/métodos , Feminino , Humanos , Masculino , Cooperação do Paciente , Fatores de Risco
9.
Trials ; 15: 381, 2014 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-25269491

RESUMO

BACKGROUND: Systematic reviews suggest that interventions that address school organisation are effective in reducing victimisation and bullying. We successfully piloted a school environment intervention modified from international studies to incorporate 'restorative justice' approaches. This trial aims to establish the effectiveness and cost-effectiveness of the INCLUSIVE intervention in reducing aggression and bullying in English secondary schools. DESIGN: cluster randomised trial. PARTICIPANTS: 40 state-supported secondary schools. OUTCOMES assessed among the cohort of students in year 8 (n = approximately 6,000) in intervention year 1. INTERVENTION: INCLUSIVE is a school-led intervention which combines changes to the school environment with the promotion of social and emotional skills and restorative practices through: the formation of a school action group involving students and staff supported by an external facilitator to review local data on needs, determine priorities, and develop and implement an action plan for revising relevant school policies/rules and other actions to improve relationships at school and reduce aggression; staff training in restorative practices; and a new social and emotional skills curriculum. The intervention will be delivered by schools supported in the first two years by educational facilitators independent of the research team, with a third locally facilitated intervention year.Comparator: normal practice. OUTCOMES: primary: 2 primary outcomes at student level assessed at baseline and at 36 months:1. Aggressive behaviours in school: Edinburgh Study of Youth Transitions and Crime school misbehaviour subscale (ESYTC)2. Bullying and victimisation: Gatehouse Bullying Scale (GBS)Secondary outcomes assessed at baseline, 24 and 36 months will include measures relating to the economic evaluation, psychosocial outcomes in students and staff and school-level truancy and exclusion rates. SAMPLE SIZE: 20 schools per arm will provide 90% power to identify an effect size of 0.25 SD with a 5% significance level.Randomisation: eligible consenting schools will be randomised stratified for single sex versus mixed sex schools, school-level deprivation and measures of school attainment. DISCUSSION: The trial will be run by independent research and intervention teams and supervised by a Trial Steering Committee and a Data Monitoring Committee (DMC). TRIAL REGISTRATION: Current Controlled Trials ISRCTN10751359 (Registered 11 March 2014).


Assuntos
Comportamento do Adolescente , Bullying/psicologia , Comportamento Infantil , Vítimas de Crime/psicologia , Instituições Acadêmicas , Estudantes/psicologia , Violência/prevenção & controle , Adaptação Psicológica , Adolescente , Fatores Etários , Criança , Análise Custo-Benefício , Emoções , Inglaterra , Feminino , Humanos , Masculino , Projetos de Pesquisa , Instituições Acadêmicas/economia , Habilidades Sociais , Inquéritos e Questionários , Fatores de Tempo , Violência/economia , Violência/psicologia
10.
Trials ; 12: 242, 2011 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-22088133

RESUMO

BACKGROUND: The childhood obesity epidemic is one of the foremost UK health priorities. Childhood obesity tracks into adult life and places individuals at considerable risk for diabetes, cardiovascular disease, liver disease and other morbidities. There is widespread need for paediatric lifestyle programmes as change may be easier to accomplish in childhood than later in life. STUDY DESIGN/METHOD: The study will evaluate the management of adolescent obesity by conducting a Medical Research Council complex intervention phase III efficacy randomised clinical trial of the Healthy Eating Lifestyle Programme within primary care. The study tests a community delivered multi-component intervention designed for adolescents developed from best practice as identified by National Institute for Health and Clinical Excellence. The hospital based pilot reduced body mass index and improved health-related quality of life.Subjects will be individually randomised to receiving either the Healthy Eating Lifestyle Programme (12 fortnightly family sessions) or enhanced standard care. Baseline and follow up assessments will be undertaken blind to allocation status. A health economic evaluation is also being conducted.200 obese young people (13-17 years, body mass index > 98th centile for age and sex) will be recruited from primary care within the greater London area.The primary hypothesis is that a motivational and solution-focused family-based weight management programme delivered over 6 months is more efficacious in reducing body mass index in obese adolescents identified in the community than enhanced standard care.The primary outcome will be body mass index at the end of the intervention, adjusted for baseline body mass index, age and sex.The secondary hypothesis is that the Healthy Eating Lifestyle Programme is more efficacious in improving quality of life and psychological function and reducing waist circumference and cardiovascular risk factors in obese adolescents than enhanced standard care assessed at 6 and 12 months post baseline assessment.Improvement in quality of life predicts on-going lifestyle change and maximises the chances of long-term weight reduction. We will explore whether improvement in QOL may be intermediate on the pathway between the intervention and body mass index change. TRIAL REGISTRATION: ISRCTN: ISRCTN99840111.


Assuntos
Protocolos Clínicos , Estilo de Vida , Obesidade/terapia , Adolescente , Índice de Massa Corporal , Ingestão de Alimentos , Feminino , Humanos , Masculino , Obesidade/psicologia , Qualidade de Vida
11.
J Immunol ; 180(3): 1414-22, 2008 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-18209036

RESUMO

Recognition of peptide-MHC by the TCR induces T lymphocytes to undergo cell division. Although recognition of foreign peptide induces a program of cellular division and differentiation by responding T cells, stimulation by self-peptide MHC complexes in lymphopenic conditions induces a slower burst of divisions that may or may not be accompanied by effector differentiation. Although both responses are triggered by signals from the TCR, it is not known whether they represent distinct programs of cell cycle control. In this study, we use a mathematical modeling approach to analyze the proliferative response of TCR transgenic F5 T cells to lymphopenia. We tested two fundamentally different models of cell division: one in which T cells are triggered into an "autopilot" deterministic burst of divisions, a model successfully used elsewhere to describe T cell responses to cognate Ag, and a second contrasting model in which cells undergo independent single stochastic divisions. Whereas the autopilot model provided a very poor description of the F5 T cell responses to lymphopenia, the model of single stochastic divisions fitted the experimental data remarkably closely. Furthermore, this model proved robust because specific predictions of cellular behavior made by this model concerning the onset, rate, and nature of division were successfully validated experimentally. Our results suggest cell division induced by lymphopenia involves a process of single stochastic divisions, which is best suited to a homeostatic rather than differentiation role.


Assuntos
Diferenciação Celular , Divisão Celular , Linfopenia/imunologia , Linfócitos T/citologia , Linfócitos T/imunologia , Animais , Antígenos/imunologia , Proliferação de Células , Camundongos , Camundongos Transgênicos , Modelos Biológicos , Receptores de Antígenos de Linfócitos T/genética
12.
Blood ; 108(6): 1949-56, 2006 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-16705084

RESUMO

The role for IL-7R expression in the differentiation of effector T cells into resting memory remains controversial. Here, using a conditional IL-7R transgenic model, we were able to test directly whether CD8 effector T cells require IL-7R expression for their differentiation into resting memory cells. In the absence of IL-7R expression, effector cells transferred into "full" hosts underwent a protracted and unremitting contraction compared with IL-7R-expressing control cells and were unable to develop into long-term resting memory cells. Surprisingly, when the same effector cells were transferred into empty T-cell-deficient hosts, they could generate long-lived fully functional resting memory cells independently of IL-7R expression. Formation of these latter cells was found to be dependent on IL-15, because the same IL-7R-deficient effector cells were rapidly lost from IL-15-deficient hosts, having a half-life of less than 40 hours. Therefore, our data suggest that, under physiological conditions, both IL-7 and IL-15 synergize to promote the formation of memory cells directly by limiting the contraction of effectors that occurs following an immune response and that reexpression of IL-7R is a key checkpoint in the regulation of this process.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Memória Imunológica , Receptores de Interleucina-7/metabolismo , Transferência Adotiva , Animais , Linfócitos T CD8-Positivos/citologia , Interleucina-15/deficiência , Interleucina-15/genética , Interleucina-15/metabolismo , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Camundongos Knockout , Camundongos Transgênicos , Receptores de Interleucina-7/deficiência , Receptores de Interleucina-7/genética
13.
Immunity ; 18(4): 523-33, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12705855

RESUMO

ZAP-70, a member of the Syk family of tyrosine kinases, has been reported to be expressed exclusively in T and NK cells. We show here that it is expressed throughout B cell development and that it plays a role in the transition of pro-B to pre-B cells in the bone marrow, a checkpoint controlled by signals from the pre-B cell receptor (pre-BCR), which monitors for successful rearrangement of immunoglobulin heavy chain genes. Whereas mice deficient in Syk show a partial block at this step, mice mutant in both Syk and ZAP-70 show a complete block at the pro-B cell stage and a failure of heavy chain allelic exclusion, hallmarks of defective pre-BCR signaling.


Assuntos
Linfócitos B/fisiologia , Células-Tronco Hematopoéticas/fisiologia , Proteínas Tirosina Quinases/fisiologia , Alelos , Animais , Precursores Enzimáticos/fisiologia , Cadeias Pesadas de Imunoglobulinas/genética , Peptídeos e Proteínas de Sinalização Intracelular , Linfopoese , Camundongos , Camundongos Endogâmicos BALB C , Receptores de Antígenos de Linfócitos B , Quinase Syk , Proteína-Tirosina Quinase ZAP-70
14.
Eur J Immunol ; 33(3): 790-7, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12616499

RESUMO

Activation of T lineage cells through the TCR by peptide-MHC complexes on APC is critically dependent on rearrangement of the actin cytoskeleton. Vav1 is a guanine nucleotide exchange factor for members of the Rho/Rac family of GTPases which is activated following TCR stimulation, suggesting that it may transduce TCR signals to the activation of some or all actin-controlled processes. We show that Vav1-deficient double-positive thymocytes are less efficient at forming conjugates with APC presenting agonist peptide than wild-type cells are. Furthermore we demonstrate that Vav1 is required for TCR-induced activation of the integrin LFA-1, which is likely to explain the defect in conjugate formation. However, once Vav1-deficient cells form a conjugate, the assembly of proteins into an immunological synapse at the conjugate interface is normal. In contrast, thymocyte polarization is defective in the absence of Vav1, as judged by the relocalization of the microtubule-organizing center. These data demonstrate that Vav1 transduces signals to only a subset of cytoskeleton-dependent events at the immunological synapse.


Assuntos
Proteínas de Ciclo Celular , Antígeno-1 Associado à Função Linfocitária/fisiologia , Proteínas Proto-Oncogênicas/fisiologia , Receptores de Antígenos de Linfócitos T/fisiologia , Transdução de Sinais/fisiologia , Sinapses/imunologia , Células Apresentadoras de Antígenos/fisiologia , Polaridade Celular , Humanos , Proteínas Proto-Oncogênicas c-vav , Proteína cdc42 de Ligação ao GTP/fisiologia
15.
Science ; 302(5644): 459-62, 2003 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-14564011

RESUMO

The Rac1 guanosine triphosphatase (GTPase) has been implicated in multiple cellular functions, including actin dynamics, proliferation, apoptosis, adhesion, and migration resulting from signaling by multiple receptors, including the B cell antigen receptor (BCR). We used conditional gene targeting to generate mice with specific Rac1 deficiency in the B cell lineage. In the absence of both Rac1 and the highly related Rac2, B cell development was almost completely blocked. Both GTPases were required to transduce BCR signals leading to proliferation, survival and up-regulation of BAFF-R, a receptor for BAFF, a key survival molecule required for B cell development and maintenance.


Assuntos
Linfócitos B/fisiologia , Receptores de Antígenos de Linfócitos B/metabolismo , Transdução de Sinais , Proteínas rac de Ligação ao GTP/fisiologia , Proteínas rac1 de Ligação ao GTP/fisiologia , Animais , Fator Ativador de Células B , Receptor do Fator Ativador de Células B , Subpopulações de Linfócitos B/fisiologia , Diferenciação Celular , Divisão Celular , Linhagem da Célula , Sobrevivência Celular , Feminino , Marcação de Genes , Ativação Linfocitária , Masculino , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Receptores do Fator de Necrose Tumoral/genética , Receptores do Fator de Necrose Tumoral/metabolismo , Recombinação Genética , Baço/citologia , Fator de Necrose Tumoral alfa/metabolismo , Regulação para Cima , Proteína RAC2 de Ligação ao GTP
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