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1.
Artigo em Inglês | MEDLINE | ID: mdl-38722601

RESUMO

OBJECTIVES: In order for parents, educators, and communities to support racially/ethnically minoritized youth to resist and heal from White supremacy, it is important to examine how youths' beliefs about their ethnic-racial identity (ERI) and critical consciousness (CC) around racism inform one another. Despite this need, limited empirical research examines whether these processes are related across adolescence. METHOD: The present two-wave longitudinal study investigates whether ERI content (i.e., centrality, private regard) and CC (i.e., critical social analysis, interpersonal antiracism actions) are associated with one another among Black and Latinx youth N = 233; young women (55.6%); young men (44.4%); M = 14.96 years old, SD = 1.46. RESULTS: Autoregressive cross-lagged panel models suggested that youths' centrality at W1 was positively and significantly associated with a critical social analysis at W2, and critical social analysis at W1 was positively and significantly associated with private regard at W2 for both groups. Involvement in interpersonal antiracism actions at W1 was positively and significantly associated with private regard at W2 for both groups. Group differences existed in the link between centrality at W1 and interpersonal antiracism actions at W2. CONCLUSION: Results indicate that ERI and CC may be viable entry points into stimulating youths' capacity to challenge racism, although there is promise in activating antiracism action to further stimulate ERI development. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

2.
Cultur Divers Ethnic Minor Psychol ; 29(1): 43-52, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34323505

RESUMO

OBJECTIVES: Many scholars and educators have written about how to approach teaching about social identities, diversity, and societal inequity in classrooms and beyond. The current article adds to this literature by considering the developmental trajectories of individuals as they engage in learning opportunities about identities, diversity, and equity. RESULTS: This article details the specific aspects of knowledge that are essential to develop cultural competence and critical consciousness as well as a sequence in which they should be acquired. CONCLUSIONS: Previous models emphasize progressive movement toward more advanced levels, but this article explains how motivation can explain movement and stalling in development. Furthermore, it analyzes the cognitive and motivational antecedents of resistance to diversity learning opportunities. The article concludes with implications for teaching and future directions for research. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Assuntos
Aprendizagem , Motivação , Humanos , Estado de Consciência , Competência Cultural , Identificação Social
3.
Artigo em Inglês | MEDLINE | ID: mdl-37498718

RESUMO

OBJECTIVES: The previous decade has seen an abundance of scholarship on the benefits of critical consciousness (CC) for racial and ethnic minority youth. However, it is unclear whether CC is a buffer against the negative effects of racial discrimination on Black adolescents' outcomes. The present study examined whether three CC dimensions buffered against the negative effects of racial discrimination on academic attitudes. METHOD: A total of 205 Black adolescents (Mage = 15.10) reported racial discrimination and CC. We conducted multiple regression analyses for each component of CC to test for their direct and protective effects on academic attitudes. RESULTS: Our results revealed associations between CC dimensions and academic attitudes. Critical reflection and critical action also buffered against racial discrimination's negative effects. CONCLUSIONS: Implications for research on the nature and impact of CC dimensions on racial discrimination and academic attitudes are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

4.
J Res Adolesc ; 32(3): 1109-1119, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35709012

RESUMO

Little is known about how different school racial climate experiences influence the critical reflection and subsequent critical action behaviors of racially minoritized youth. Therefore, the current study examined how critical reflection mediated the relationship between school racial climate profiles and critical action behaviors. Participants were 559 Black and Latinx adolescents, aged 13-17 who completed an online survey. Results indicated that critical reflection significantly mediated the relationships between interpersonal interactions (i.e., equal status) and anti-racist critical action behaviors. Similarly, the relationships between school racial socialization messages (i.e., cultural and critical consciousness socialization) and anti-racist critical action behaviors were also mediated by critical reflection. Findings have implications for how dimensions of the school racial climate differentially relate to racially minoritized youth's critical consciousness.


Assuntos
Relações Interpessoais , Socialização , Adolescente , Humanos , Grupos Raciais , Instituições Acadêmicas , Inquéritos e Questionários
5.
Cultur Divers Ethnic Minor Psychol ; 28(2): 205-216, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34941284

RESUMO

OBJECTIVE: Schools are an influential source of information on the meaning of race and culture in society and adolescents' personal lives. Yet, that influence is understudied in the literature on adolescent ethnic-racial identity (ERI) development. Studies of ethnic-racial socialization tend to focus on the family context; the current study measures adolescents' perceptions of ethnic-racial socialization from the school context. METHODS: The sample includes 819 youth aged 12-18 (M = 15.27, SD = 1.58) from 4 ethnic-racial groups. We used structural equation modeling to examine the relations between ethnic-racial socialization and ERI controlling for race, gender, and age. To examine ethnic-racial group membership as a moderator, a multigroup model was used. RESULTS: The findings show that, across ethnic-racial groups, the perceptions of opportunities to learn about one's ethnic-racial background and messages about American values are positively associated with youths' exploration of and commitment to their identities. Furthermore, color-blind socialization messages were associated with lower identity commitment. CONCLUSIONS: The findings highlight the importance of the school context in shaping students' ethnic-racial socialization and identity. This study investigated how what adolescents learn about race/ethnicity and culture in school is associated with their ERI. The findings indicate that opportunities to learn about one's culture are related to more identity exploration and greater sense of the importance of group membership. Furthermore, opportunities to learn about other cultures promote positive attitudes toward people of different races/ethnicities. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Assuntos
Etnicidade , Socialização , Adolescente , Criança , Humanos , Grupos Raciais , Instituições Acadêmicas , Identificação Social
6.
J Community Psychol ; 48(6): 1942-1963, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32526066

RESUMO

Given that ecological models of development highlight the interacting influences of multiple environments, further research is needed that explores ethnic-racial socialization from multiple contexts. The current study explores how families, schools, neighborhoods, and the Internet jointly impact academic outcomes, critical consciousness, and psychological well-being in adolescents, both through socialization messages and experiences with racial discrimination. The research questions were: (a) What profiles of multiple contexts of socialization exist? and (b) How are the different profiles associated with academic outcomes, critical consciousness, and psychological well-being? The sample consisted of 1,084 U.S. adolescents aged 13-17 (M = 14.99, SD = 1.37; 49% girls) from four ethnic-racial groups: 25.6% Asian American, 26.3% Black/African American, 25.3% Latinx, and 22.9% White. The participants completed online surveys of socialization and discrimination from four contexts and three types of outcomes: academic outcomes, critical consciousness, and well-being. A latent profile analysis revealed three profiles: Average, High Discrimination, and Positive School. The Positive School class had the most positive academic outcomes and well-being. The High Discrimination class reported the highest critical consciousness. Their academic outcomes and well-being were similar to the Average group. The findings support complexity in perceptions of socialization from different contexts and the associations of socialization with youth outcomes.


Assuntos
Desempenho Acadêmico/estatística & dados numéricos , Saúde do Adolescente/estatística & dados numéricos , Família/psicologia , Racismo/psicologia , Percepção Social/psicologia , Socialização , Desempenho Acadêmico/tendências , Adolescente , Negro ou Afro-Americano/psicologia , Negro ou Afro-Americano/estatística & dados numéricos , Asiático/psicologia , Asiático/estatística & dados numéricos , Estado de Consciência/fisiologia , Estudos Transversais , Feminino , Hispânico ou Latino/psicologia , Hispânico ou Latino/estatística & dados numéricos , Humanos , Internet/estatística & dados numéricos , Masculino , Características de Residência/estatística & dados numéricos , Instituições Acadêmicas/estatística & dados numéricos , Percepção Social/etnologia , Inquéritos e Questionários/estatística & dados numéricos , Estados Unidos/etnologia , População Branca/psicologia , População Branca/estatística & dados numéricos
7.
Cultur Divers Ethnic Minor Psychol ; 25(2): 137-151, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29952579

RESUMO

OBJECTIVES: The current study presents a comprehensive framework of campus racial climate and tests the validity and reliability of a new measure, the School Climate for Diversity Scale-College, in three independent samples. The scale measures 10 dimensions of campus racial climate in the two domains of intergroup interactions (frequency of interaction, quality of interaction, equal status, support for positive interaction, and stereotyping) and campus racial socialization (cultural socialization, mainstream socialization, promotion of cultural competence, colorblind socialization, and critical consciousness socialization). METHOD: Participants were college students drawn from an online task system and a public university on the West Coast. RESULTS AND CONCLUSIONS: Study 1 provided evidence of reliability and validity with existing measures of college climate, whereas Study 2 provided evidence of factor stability through exploratory factor analysis as well as additional evidence of discriminant and concurrent validity. Finally, Study 3 replicated the factor structure of Study 2 and provided further evidence of validity. (PsycINFO Database Record (c) 2019 APA, all rights reserved).


Assuntos
Competência Cultural/psicologia , Identificação Social , Socialização , Inquéritos e Questionários/normas , Feminino , Humanos , Relações Interpessoais , Masculino , Psicometria , Grupos Raciais , Reprodutibilidade dos Testes , Percepção Social , Estudantes/psicologia , Universidades , Adulto Jovem
8.
Child Dev ; 89(6): e552-e571, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29154406

RESUMO

This study examines school climate, racial identity beliefs, and achievement motivation beliefs within a cultural-ecological and risk and resilience framework. Data were drawn from a longitudinal study of 733 (Mage  = 14.49) African American adolescent girls. A linear mixed effects model was used to determine if racial identity dimensions moderated the relationship between school climate and achievement motivation beliefs across four waves. Results revealed that racial identity (private regard and racial centrality) and ideology (nationalist) beliefs were associated with higher achievement motivation beliefs over time, while racial centrality and private regard, and a sense of belonging served as protective factors. The findings contribute to the importance of racial identity beliefs and increase the visibility of African American girls.


Assuntos
Negro ou Afro-Americano/psicologia , Resiliência Psicológica , Identificação Social , Adolescente , Criança , Feminino , Humanos , Relações Interpessoais , Estudos Longitudinais , Motivação , Fatores de Proteção , Instituições Acadêmicas , Estados Unidos
9.
J Couns Psychol ; 62(2): 216-25, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25867694

RESUMO

Scholars agree on the negative impacts of racial discrimination on the mental health of African Americans (Brondolo et al., 2008). Yet research is needed to explore the impacts of everyday discrimination over time, especially compared to nonracial daily hassles, in an ecologically valid manner. It is also widely accepted that racial identity can moderate the impact of racial hassles (Sellers, Copeland-Linder, Martin, & Lewis 2006), but few studies have examined this moderating effect over time. The current study addresses gaps in the current literature by analyzing the relationship between reported racial and nonracial stressors over the course of four days. Participants were 225 college students at three institutions who participated in a 20-day daily diary study. Each day, participants reported whether they had experienced a stressful event and their depressive symptoms. We compared reports of depressive symptoms the day an event occurred and two days after for racial and nonracial stressors and examined whether racial identity served as a moderator. The results showed that individuals experienced similar increases for racial and nonracial stressors when events occur and similar decreases in the following two days. Additionally, symptom trajectories varied by racial identity. Implications for the understanding of racial discrimination's role in the well-being of African Americans are discussed.


Assuntos
Negro ou Afro-Americano/psicologia , Depressão/psicologia , Saúde Mental , Racismo/psicologia , Feminino , Humanos , Masculino , Estresse Psicológico/psicologia , Estudantes/psicologia , Adulto Jovem
10.
Cultur Divers Ethnic Minor Psychol ; 18(4): 329-39, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22866688

RESUMO

Racial discrimination, a common experience for many African Americans, has been conceptualized within a stress and coping framework. However, few have examined whether racially stressful events are appraised and coped with differently from nonracially stressful events. The present study uses a daily diary method to examine African American college students' appraisals and coping behaviors in racially and nonracially stressful situations. The study examines the following 3 questions: 1) Do African Americans appraise racially stressful events differently from nonracially stressful events? 2) Do they cope with racially stressful events differently from nonracially stressful events? and 3) Do they cope with racially stressful events differently from nonracially stressful events, even after controlling for differences in cognitive appraisals of the events? The present sample consists of 35 participants who reported experiencing at least one racially stressful event and at least one nonracially stressful event during a 20-day diary study. Overall, no differences were found in students' appraisals in the racially stressful versus nonracially stressful events. Participants used less planful problem solving and more confrontive, ruminative, and avoidance coping strategies in the racially stressful events as compared with the nonracially stressful events. These findings suggest a need for race-specific models for coping with racial discrimination. (PsycINFO Database Record (c) 2012 APA, all rights reserved).


Assuntos
Adaptação Psicológica , Negro ou Afro-Americano/psicologia , Racismo/psicologia , Estresse Psicológico/etnologia , Estudantes/psicologia , Adolescente , Cognição , Feminino , Humanos , Acontecimentos que Mudam a Vida , Masculino , Personalidade , Preconceito , Resolução de Problemas , Estresse Psicológico/psicologia , Adulto Jovem
11.
J Sch Psychol ; 91: 97-111, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35190082

RESUMO

Experiences with race-related stressors at school are linked to negative academic consequences, such as lowered belonging and engagement. One factor known to buffer racial stressors is ethnic-racial socialization (ERS). Although students receive ERS messages in school, less is known about how school ERS may reduce the negative consequences of school race-related stress (SRS) on youth's academic outcomes. To date no studies have examined the moderating effects of school ERS on SRS and whether the associations vary for African American and Latinx youth. Thus, the current study examined the direct effects of SRS and school ERS on youth's academic well-being, the moderating role of school ERS against SRS, and whether these associations varied for African American and Latinx youth. Multiple group regression analysis with 221 African American and 219 Latinx adolescents demonstrated that SRS was negatively associated with the academic outcomes. Cultural socialization was associated with more positive outcomes. Furthermore, there were significant interactions between SRS and color-evasive socialization, such that SRS was associated with lower belonging at higher compared to lower levels of color-evasive messages. Additionally, SRS was associated with less school engagement for those who reported high color-evasive socialization messages, but there was no association for those who reported low color-evasive messages. The results indicate that color-evasive school ERS messages can exacerbate the negative associations between SRS and academic well-being for both African American and Latinx youth and highlight how school racialized experiences may have unique or similar effects across groups. Implications for culturally relevant school practices and interventions are discussed.


Assuntos
Racismo , Socialização , Adolescente , Negro ou Afro-Americano , Etnicidade , Humanos , Instituições Acadêmicas , Identificação Social
12.
Res Hum Dev ; 17(2-3): 130-153, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-38239301

RESUMO

Research on ethnic-racial identity (ERI) and its development has increased exponentially over the past decade. In this paper we discuss five questions that the Lifespan ERI Study Group grappled with in our effort propose a lifespan model of ERI: (1) When does ERI development begin and end? (2) How do we account for age-dependent and contextually-initiated factors in ERI? (3) Should there be a reference point for healthy ERI, and if so, what is it? (4) How do the multiplicities of identity (intersectionality, multiracialism, whiteness) figure into our conceptualization of ERI? (5) How do we understand the role of ERI in pursuit of equity, diversity, and social justice? We note that these are persistent questions in ERI research, and thus our goal is to present our collective reckoning with these issues as well as our ponderings about why they persist. We conclude with recommendations forthe kinds of research questions, designs, and methods that developmental science, in particular, needs to pursue.

13.
Res Hum Dev ; 17(2-3): 99-129, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-38250240

RESUMO

The current paper presents a lifespan model of ethnic-racial identity (ERI) from infancy into adulthood. We conceptualize that ethnic-racial priming during infancy prompts nascent awareness of ethnicity/race that becomes differentiated across childhood and through adulthood. We propose that the components of ERI that have been tested to date fall within five dimensions across the lifespan: ethnic-racial awareness, affiliation, attitudes, behaviors, and knowledge. Further, ERI evolves in a bidirectional process informed by an interplay of influencers (i.e., contextual, individual, and developmental factors, as well as meaning-making and identity-relevant experiences). It is our goal that the lifespan model of ERI will provide important future direction to theory, research, and interventions.

14.
J Youth Adolesc ; 38(4): 544-59, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19636727

RESUMO

Increasingly, researchers have found relationships between a strong, positive sense of racial identity and academic achievement among African American youth. Less attention, however, has been given to the roles and functions of racial identity among youth experiencing different social and economic contexts. Using hierarchical linear modeling, the authors examined the relationship of racial identity to academic outcomes, taking into account neighborhood-level factors. The sample consisted of 564 African American eighth-graders (56% male). The authors found that neighborhood characteristics and racial identity related positively to academic outcomes, but that some relationships were different across neighborhood types. For instance, in neighborhoods low in economic opportunity, high pride was associated with a higher GPA, but in more advantaged neighborhoods, high pride was associated with a lower GPA. The authors discuss the need to take youth's contexts into account in order to understand how racial identity is active in the lives of African American youth.


Assuntos
Logro , Grupos Raciais/psicologia , Grupos Raciais/estatística & dados numéricos , Características de Residência , Autoimagem , Identificação Social , Adolescente , Negro ou Afro-Americano/psicologia , Negro ou Afro-Americano/estatística & dados numéricos , Anomia (Social) , Criança , Análise por Conglomerados , Etnicidade/psicologia , Etnicidade/estatística & dados numéricos , Feminino , Humanos , Masculino , Comportamento Social , Inquéritos e Questionários
15.
Br J Educ Psychol ; 87(4): 700-721, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28850714

RESUMO

BACKGROUND: The conceptualization of the role of race and culture in students' experience of school has been limited. This study presents a more comprehensive and multidimensional framework than previously conceptualized and includes the two domains of (1) intergroup interactions (frequency of interaction, quality of interaction, equal status, and support for positive interaction) and (2) school racial socialization (cultural socialization, mainstream socialization, promotion of cultural competence, colourblind socialization, critical consciousness socialization, and stereotyping) (Byrd, 2015, Journal of Educational Research, 108, 10). AIMS: The scale presents a measure of school racial climate for middle and high school students and tests for evidence of reliability and validity in two independent, nationwide samples. SAMPLE AND METHOD: Participants were 819 children aged 12-18 (M = 15.27, SD = 1.58) who completed the School Climate for Diversity - Secondary Scale and a number of validating measures: general school climate, perceived discrimination, culturally responsive teaching, grades, and academic motivation. RESULTS AND CONCLUSIONS: Confirmatory factor analyses and reliability analyses showed support for the 10-factor structure of the scale, and the subscales were associated with the validating measures in expected ways.


Assuntos
Diversidade Cultural , Psicometria/normas , Grupos Raciais/psicologia , Socialização , Adolescente , Criança , Feminino , Humanos , Masculino , Psicometria/instrumentação , Reprodutibilidade dos Testes
16.
J Sch Psychol ; 57: 1-14, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27425562

RESUMO

Although there exists a healthy body of literature related to discrimination in schools, this research has primarily focused on racial or ethnic discrimination as perceived and experienced by students of color. Few studies examine students' perceptions of discrimination from a variety of sources, such as adults and peers, their descriptions of the discrimination, or the frequency of discrimination in the learning environment. Middle and high school students in a Midwestern school district (N=1468) completed surveys identifying whether they experienced discrimination from seven sources (e.g., peers, teachers, administrators), for seven reasons (e.g., gender, race/ethnicity, religion), and in eight forms (e.g., punished more frequently, called names, excluded from social groups). The sample was 52% White, 15% Black/African American, 14% Multiracial, and 17% Other. Latent class analysis was used to cluster individuals based on reported sources of, reasons for, and forms of discrimination. Four clusters were found, and ANOVAs were used to test for differences between clusters on perceptions of school climate, relationships with teachers, perceptions that the school was a "good school," and engagement. The Low Discrimination cluster experienced the best outcomes, whereas an intersectional cluster experienced the most discrimination and the worst outcomes. The results confirm existing research on the negative effects of discrimination. Additionally, the paper adds to the literature by highlighting the importance of an intersectional approach to examining students' perceptions of in-school discrimination.


Assuntos
Preconceito/psicologia , Instituições Acadêmicas , Percepção Social , Estudantes/psicologia , Adolescente , Feminino , Humanos , Masculino , Michigan/etnologia , Preconceito/etnologia
17.
Mol Immunol ; 47(4): 756-62, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19942291

RESUMO

The production of superoxide from NADPH oxidase by macrophages in response to endotoxin (LPS) is an important innate immune response, yet it is not clear how LPS signals the activation of NADPH oxidase. The hypothesis is that LPS-induced src kinase and PI3 kinase (PI3K) facilitates the activation of p47(phox), the regulatory subunit of NADPH oxidase. In mouse macrophage RAW264.7 cells, inhibition of src tyrosine family kinases inhibited LPS-induced activation of NADPH oxidase, phosphorylation of p47(phox), activation of PI3K and phosphorylation of the TLR4. Moreover, inhibition of LPS-induced increases in intracellular calcium blunted src kinase activation, PI3K association with TLR4, as well as PI3 kinase activation. These data suggest that both src kinase and PI3 kinase are involved in LPS-induced NADPH oxidase activation. Importantly, these data suggest that LPS-induced src kinase activation is critical for PI3 kinase activation as well as TLR4 phosphorylation and is dependent upon LPS-induced increase in intracellular calcium. These signaling events fill critical gaps in our understanding of LPS-induced free radical production as well as may potentially responsible for the mechanism of innate immune tolerance or desensitization caused by steroids or ethanol.


Assuntos
Lipopolissacarídeos/farmacologia , NADPH Oxidases/metabolismo , Quinases da Família src/metabolismo , Animais , Cálcio/metabolismo , Linhagem Celular , Quelantes/farmacologia , Ativação Enzimática/efeitos dos fármacos , Espaço Intracelular/efeitos dos fármacos , Espaço Intracelular/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/enzimologia , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , Fosforilação/efeitos dos fármacos , Ligação Proteica/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Superóxidos/metabolismo , Receptor 4 Toll-Like/metabolismo , Quinases da Família src/antagonistas & inibidores
18.
Hepatology ; 46(1): 229-41, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17596893

RESUMO

UNLABELLED: The regeneration of liver tissue following transplantation is often complicated by inflammation and tissue damage induced by a number of factors, including ischemia and reperfusion injury and immune reactions to the donor tissue. The purpose of the current study is to characterize the effects of T cell-mediated hepatitis induced by concanavalin A (ConA) on the regenerative response in vivo. Liver regeneration following a partial (70%) hepatectomy (pHx) was associated with elevations in serum enzymes and the induction of key cell cycle proteins (cyclin D, cyclin E, and Stat3) and hepatocyte proliferation. The induction of T cell-mediated hepatitis 4 days before pHx increased serum enzymes 48 hours after pHx, reduced early cyclin D expression and Stat3 activation, and suppressed hepatocyte proliferation. This inhibition of proliferation was also associated with increased expression of p21, the activation of Smad2, the induction of transforming growth factor beta and interferon gamma expression, and reduced hepatic interleukin 6 production. Moreover, the ConA pretreatment increased the numbers of separate oval cell-like CD117(+) cells and hematopoietic-like Sca-1(+) cell populations 48 hours following pHx. The depletion of natural killer (NK) cells, an important component of the innate immune response, did not affect liver injury or ConA-induced impairment of hepatocyte proliferation but did increase the numbers of both CD117-positive and Sca-1-positive cell populations. Finally, splenocytes isolated from ConA-pretreated mice exerted cytotoxicity toward autologous bone marrow cells in an NK cell-dependent manner. CONCLUSION: T cell-mediated hepatitis alters early cytokine responses, reduces hepatocellular regeneration, and induces NK cell-sensitive oval cell and hematopoietic-like cell expansion following pHx.


Assuntos
Hepatite/patologia , Regeneração Hepática/fisiologia , Linfócitos T/patologia , Animais , Sobrevivência Celular , Concanavalina A/toxicidade , Genes Reporter , Hepatite/imunologia , Hepatite/fisiopatologia , Interferon gama/genética , Interleucina-6/genética , Células Matadoras Naturais/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos SCID , Camundongos Transgênicos , Reação em Cadeia da Polimerase , Linfócitos T/imunologia , Fator de Crescimento Transformador beta/genética , Fator de Necrose Tumoral alfa/genética
19.
Am J Physiol Gastrointest Liver Physiol ; 290(6): G1318-28, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16439470

RESUMO

Although it is clear that bile acid accumulation is the major initiator of fibrosis caused by cholestatic liver disease, endotoxemia is a common side effect. However, the depletion of hepatic macrophages with gadolinium chloride blunts hepatic fibrosis. Because endotoxin is a key activator of hepatic macrophages, this study was designed to test the hypothesis that LPS signaling through CD14 contributes to hepatic fibrosis caused by experimental cholestasis. Wild-type mice and CD14 knockout mice (CD14(-/-)) underwent sham operation or bile duct ligation and were killed 3 wk later. Measures of liver injury, such as focal necrosis, biliary cell proliferation, and inflammatory cell influx, were not significantly different among the strains 3 wk after bile duct ligation. Markers of liver fibrosis such as Sirius red staining, liver hydroxyproline, and alpha-smooth muscle actin expression were blunted in CD14(-/-) mice compared with wild-type mice after bile duct ligation. Despite no difference in lymphocyte infiltration, the macrophage/monocyte activation marker OX42 (CD11b) and the oxidative stress/lipid peroxidation marker 4-hydroxynonenal were significantly upregulated in wild-type mice after bile duct ligation but not in CD14(-/-) mice. Increased profibrogenic cytokine mRNA expression in the liver after bile duct ligation was significantly blunted in CD14(-/-) mice compared with the wild type. The hypothesis that LPS was involved in experimental cholestatic liver fibrosis was tested using mice deficient in LPS-binding protein (LBP(-/-)). LBP(-/-) mice had less liver injury and fibrosis (Siruis red staining and hydroxyproline content) compared with wild-type mice after bile duct ligation. In conclusion, these data demonstrate that endotoxin in a CD14-dependent manner exacerbates hepatic fibrogenesis and macrophage activation to produce oxidants and cytokines after bile duct ligation.


Assuntos
Colestase/imunologia , Colestase/patologia , Modelos Animais de Doenças , Receptores de Lipopolissacarídeos/imunologia , Lipopolissacarídeos/imunologia , Cirrose Hepática/imunologia , Cirrose Hepática/patologia , Animais , Colestase/complicações , Fígado/imunologia , Fígado/patologia , Cirrose Hepática/etiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Transdução de Sinais/imunologia
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