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1.
JAMA ; 321(4): 354-363, 2019 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-30694322

RESUMO

Importance: Dexamethasone initiated after the first week of life reduces the rate of death or bronchopulmonary dysplasia (BPD) but may cause long-term adverse effects in very preterm infants. Hydrocortisone is increasingly used as an alternative, but evidence supporting its efficacy and safety is lacking. Objective: To assess the effect of hydrocortisone initiated between 7 and 14 days after birth on death or BPD in very preterm infants. Design, Setting, and Participants: Double-blind, placebo-controlled randomized trial conducted in 19 neonatal intensive care units in the Netherlands and Belgium from November 15, 2011, to December 23, 2016, among preterm infants with a gestational age of less than 30 weeks and/or birth weight of less than 1250 g who were ventilator dependent between 7 and 14 days of life, with follow-up to hospital discharge ending December 12, 2017. Interventions: Infants were randomly assigned to receive a 22-day course of systemic hydrocortisone (cumulative dose, 72.5 mg/kg) (n = 182) or placebo (n = 190). Main Outcomes and Measures: The primary outcome was a composite of death or BPD assessed at 36 weeks' postmenstrual age. Twenty-nine secondary outcomes were analyzed up to hospital discharge, including death and BPD at 36 weeks' postmenstrual age. Results: Among 372 patients randomized (mean gestational age, 26 weeks; 55% male), 371 completed the trial; parents withdrew consent for 1 child treated with hydrocortisone. Death or BPD occurred in 128 of 181 infants (70.7%) randomized to hydrocortisone and in 140 of 190 infants (73.7%) randomized to placebo (adjusted risk difference, -3.6% [95% CI, -12.7% to 5.4%]; adjusted odds ratio, 0.87 [95% CI, 0.54-1.38]; P = .54). Of 29 secondary outcomes, 8 showed significant differences, including death at 36 weeks' postmenstrual age (15.5% with hydrocortisone vs 23.7% with placebo; risk difference, -8.2% [95% CI, -16.2% to -0.1%]; odds ratio, 0.59 [95% CI, 0.35-0.995]; P = .048). Twenty-one outcomes showed nonsignificant differences, including BPD (55.2% with hydrocortisone vs 50.0% with placebo; risk difference, 5.2% [95% CI, -4.9% to 15.2%]; odds ratio, 1.24 [95% CI, 0.82-1.86]; P = .31). Hyperglycemia requiring insulin therapy was the only adverse effect reported more often in the hydrocortisone group (18.2%) than in the placebo group (7.9%). Conclusions and Relevance: Among mechanically ventilated very preterm infants, administration of hydrocortisone between 7 and 14 days after birth, compared with placebo, did not improve the composite outcome of death or BPD at 36 weeks' postmenstrual age. These findings do not support the use of hydrocortisone for this indication. Trial Registration: Netherlands National Trial Register Identifier: NTR2768.


Assuntos
Anti-Inflamatórios/administração & dosagem , Displasia Broncopulmonar/prevenção & controle , Hidrocortisona/administração & dosagem , Doenças do Prematuro/mortalidade , Recém-Nascido de muito Baixo Peso , Anti-Inflamatórios/efeitos adversos , Método Duplo-Cego , Humanos , Hidrocortisona/efeitos adversos , Incidência , Recém-Nascido , Recém-Nascido Prematuro , Doenças do Prematuro/prevenção & controle , Unidades de Terapia Intensiva Neonatal , Respiração Artificial , Tempo para o Tratamento , Falha de Tratamento
2.
Intensive Crit Care Nurs ; 80: 103562, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37871352

RESUMO

OBJECTIVES: This study aimed to compare the use of a conventional low-tech communication board and a high-tech eye tracking device to improve communication effectiveness of mechanically ventilated patients in intensive care. DESIGN: A prospective randomized crossover was conducted with a mixed method approach (quantitative primary method and qualitative complementary method) to compare the two technologically opposed communication interfaces. SETTING: The mechanically ventilated patients were recruited from the general intensive care unit of the Marie Curie Civil Hospital (Charleroi University Hospital, Belgium). MAIN OUTCOME MEASURES: The communication exchanges were assessed through effectiveness indicators covering the quantity of messages transmitted, success rate, patient satisfaction, communication content and difficulties of use. RESULTS: The sample consisted of 44 mechanically ventilated patients, covering 88 communication exchanges. The intervention effects on the quantity of messages transmitted (two median messages per exchange for the board versus four median messages per exchange for the eye tracking, p < 0.0001), success rate (80 % for the board versus 100 % for the eye tracking, p < 0.05) and patient satisfaction (66 % "not satisfied", 32 % "satisfied" and 2 % "dissatisfied" for the board versus 52 % "satisfied" and 48 % "very satisfied" for the eye tracking, p < 0.0001) were significant. The communication content covered eight themes for the board compared to nine themes for the eye tracking and the use difficulties included four categories for the board as well as for the eye tracking. CONCLUSION: The eye tracking device may further improve communication effectiveness of mechanically ventilated patients compared to the conventional communication board, both quantitatively and qualitatively. IMPLICATIONS FOR CLINICAL PRACTICE: The implementation of high-tech communication devices based on eye tracking in intensive care practice can significantly contribute to patient-centered care by improving communication of mechanically ventilated patients.


Assuntos
Comunicação , Cuidados Críticos , Respiração Artificial , Humanos , Unidades de Terapia Intensiva , Estudos Prospectivos , Respiração Artificial/efeitos adversos , Estudos Cross-Over
3.
Heliyon ; 10(11): e32350, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38947466

RESUMO

Environmental toxins, particularly liposoluble compounds that accumulate in adipose tissues, present a risk for newborns, not only through breastfeeding but also through artificial milks. These compounds pass into breast milk, potentially exposing infants to harmful substances. In a monocentric observational study carried out in the Charleroi region, we employed liquid chromatography coupled with mass spectrometry to analyze the presence of environmental toxins in milk for newborns. Out of 39 breast milk and 12 artificial milk samples analyzed, 15 and six contained at least one pesticide, respectively, with nine different pesticides identified from a panel of 54 substances tested. The study found an association between the consumption of fresh produce and a higher presence of pesticides in breast milk. This. highlights the broader issue of environmental toxin exposure for infants, regardless of the feeding method. The results underline the need for a comprehensive approach when considering the establishment of breast milk banks and the safety of artificial milk, especially in the context of potential risks to premature newborns. Our findings not only validate the analysis technique for detecting toxins in breast milk but also suggest the necessity for a larger prospective study to explore these risks in the future.

4.
Arch Dis Child Fetal Neonatal Ed ; 109(2): 159-165, 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-37722765

RESUMO

OBJECTIVE: To explore clinical effect modifiers of systemic hydrocortisone in ventilated very preterm infants for survival and neurodevelopmental outcome at 2 years' corrected age (CA). DESIGN: Secondary analysis of a randomised placebo-controlled trial. SETTING: Dutch and Belgian neonatal intensive care units. PATIENTS: Infants born <30 weeks' gestational age (GA), ventilator-dependent in the second week of postnatal life. INTERVENTION: Infants were randomly assigned to systemic hydrocortisone (cumulative dose 72.5 mg/kg; n=182) or placebo (n=190). MAIN OUTCOME MEASURES: The composite of death or neurodevelopmental impairment (NDI) at 2 years' CA and its components. Candidate effect modifiers (GA, small for GA, respiratory index, sex, multiple births, risk of moderate/severe bronchopulmonary dysplasia or death) were analysed using regression models with interaction terms and subpopulation treatment effect pattern plots. RESULTS: The composite outcome was available in 356 (96.0%) of 371 patients (one consent withdrawn). For this outcome, treatment effect heterogeneity was seen across GA subgroups (<27 weeks: hydrocortisone (n=141) vs placebo (n=156), 54.6% vs 66.2%; OR 0.61 (95% CI 0.38 to 0.98); ≥27 weeks: hydrocortisone (n=30) vs placebo (n=31), 66.7% vs 45.2%; OR 2.43 (95% CI 0.86 to 6.85); p=0.02 for interaction). This effect was also found for the component death (<27 weeks: 20.1% vs 32.1%; OR 0.53 (95% CI 0.32 to 0.90); ≥27 weeks: 28.1% vs 16.1%; OR 2.04 (95% CI 0.60 to 6.95); p=0.049 for interaction) but not for the component NDI. No differential treatment effects were observed across other subgroups. CONCLUSION: This secondary analysis suggests that in infants <27 weeks' GA, systemic hydrocortisone may improve the outcome death or NDI, mainly driven by its component death. There was insufficient evidence for other selected candidate effect modifiers.


Assuntos
Displasia Broncopulmonar , Doenças do Prematuro , Lactente , Recém-Nascido , Humanos , Hidrocortisona , Recém-Nascido Prematuro , Recém-Nascido de muito Baixo Peso , Glucocorticoides/uso terapêutico , Doenças do Prematuro/tratamento farmacológico
5.
Arch Dis Child Fetal Neonatal Ed ; 108(1): 20-25, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35534184

RESUMO

OBJECTIVE: Observational studies in preterm infants suggest that systemic hydrocortisone improves pulmonary condition but may also lead to systemic adverse effects. We report the short-term pulmonary and systemic effects of hydrocortisone initiated in the second week. DESIGN: Randomised placebo-controlled trial. SETTING: Dutch and Belgian neonatal intensive care units. PATIENTS: Infants born <30 weeks' gestation and/or birth weight <1250 g, and ventilator dependent in the second week of life. INTERVENTION: Infants were randomly assigned to a 22-day course of systemic hydrocortisone (cumulative dose 72.5 mg/kg; n=182) or placebo (n=190). MAIN OUTCOME MEASURES: Data on extubation, ventilator settings, glucose levels, and blood pressure were recorded daily and analysed during the first 7 days of treatment using linear mixed-effects models. RESULTS: Infants in the hydrocortisone group (24.3%) failed extubation less often compared with placebo (38.6%, crude risk difference: -14.3% (95% CI: -23.4% to -4.8%)). The estimated difference in daily rate of change between hydrocortisone and placebo was -0.42 cmH2O (95% CI: -0.48 to -0.36) for mean airway pressure, -0.02 (95% CI: -0.02 to -0.01) for fraction of inspired oxygen, -0.37 (95% CI: -0.44 to -0.30) for respiratory index, 0.14 mmol/L (95% CI: 0.08 to 0.21) for blood glucose levels and 0.83 mm Hg (95% CI: 0.58 to 1.09) for mean blood pressure. CONCLUSIONS: Systemic hydrocortisone initiated between 7 and 14 days after birth in ventilated preterm infants improves pulmonary condition, thereby facilitating weaning and extubation from invasive ventilation. The effects of hydrocortisone on blood glucose levels and blood pressure were mild and of limited clinical relevance. TRIAL REGISTRATION NUMBER: Netherlands Trial Register (NTR2768; https://www.trialregister.nl/trial/2640) and European Union Clinical Trials Register (EudraCT, 2010-023777-19).


Assuntos
Doenças do Prematuro , Pneumopatias , Lactente , Recém-Nascido , Humanos , Hidrocortisona/efeitos adversos , Recém-Nascido Prematuro , Glicemia , Recém-Nascido de muito Baixo Peso , Doenças do Prematuro/tratamento farmacológico
6.
Arch Dis Child Fetal Neonatal Ed ; 108(4): 373-379, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36593110

RESUMO

OBJECTIVE: To report the parent-reported behavioural outcomes of infants included in the Systemic Hydrocortisone To Prevent Bronchopulmonary Dysplasia in preterm infants study at 2 years' corrected age (CA). DESIGN: Randomised placebo-controlled trial. SETTING: Dutch and Belgian neonatal intensive care units. PATIENTS: Infants born <30 weeks' gestation and/or birth weight <1250 g, and ventilator dependent in the second week of life. INTERVENTION: Infants were randomly assigned to a 22-day course of systemic hydrocortisone (cumulative dose 72.5 mg/kg; n=182) or placebo (n=190). MAIN OUTCOME MEASURES: Parent-reported behavioural outcomes at 2 years' CA assessed with the Child Behavior Checklist (CBCL 1½-5). RESULTS: Parents completed the CBCL of 183 (70% (183/262)) infants (hydrocortisone group, n=96; placebo group, n=87). Multiple imputation was used to account for missing data. Infants with critically elevated T-scores (>55) were found in 22.9%, 19.1% and 29.4% of infants for total, internalising and externalising problems, respectively; these scores were not significantly different between groups (mean difference -1.52 (95% CI -4.00 to 0.96), -2.40 (95% CI -4.99 to 0.20) and -0.81 (95% CI -3.40 to 1.77), respectively). In the subscales, we found a significantly lower T-score for anxiety problems in the hydrocortisone group (mean difference -1.26, 95% CI -2.41 to -0.12). CONCLUSION: This study found high rates of behaviour problems at 2 years' CA following very preterm birth, but these problems were not associated with hydrocortisone treatment initiated between 7 and 14 days after birth in ventilated preterm infants. TRIAL REGISTRATION NUMBER: NTR2768; EudraCT 2010-023777-19.


Assuntos
Displasia Broncopulmonar , Nascimento Prematuro , Lactente , Criança , Feminino , Recém-Nascido , Humanos , Hidrocortisona/uso terapêutico , Recém-Nascido Prematuro , Seguimentos , Nascimento Prematuro/tratamento farmacológico , Glucocorticoides/uso terapêutico , Displasia Broncopulmonar/prevenção & controle , Displasia Broncopulmonar/tratamento farmacológico , Recém-Nascido de muito Baixo Peso
7.
Neonatology ; 119(6): 753-759, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36030773

RESUMO

INTRODUCTION: Currently, INSURE (Intubation-Surfactant-Extubation) and LISA (Less Invasive Surfactant Administration) are two recommended techniques for surfactant delivery to newborns with respiratory distress syndrome. The aim of this study was to evaluate the feasibility, safety, tolerability of a new technique of surfactant administration in newborns without anesthesia or laryngoscopy: Fiberscope Assisted Surfactant Therapy (FAST). METHODS: This monocentric, prospective, nonrandomized, pilot feasibility study was conducted from January to December 2021. Spontaneously breathing infants born ≥28 weeks gestational age with respiratory distress syndrome received surfactant by a 1.5 French catheter inserted in the trachea using a flexible endoscope without anesthesia, while maintaining a continuous positive expiratory pressure. The learning curve of this new technique by caregivers was studied during training sessions on high fidelity mannequins. RESULTS: Eight infants born ≥28 weeks of gestation with a birth weight of 1,000 g-2,685 g were included in the study. FAST was successfully performed in each case without anesthesia, second dose of surfactant or mechanical ventilation. One hour after FAST, a decrease of FiO2 and PCO2 and an increase of arterial pressure and pH were recorded with medians of individual differences of -0.9, -4 mm Hg, 6.5 mm Hg, and 0.06, respectively. The learning curves of 13 physicians showed a rapid mastery of FAST from the third attempt onwards (mean duration of 113, 66, and 50 s for 1st, 2nd, and 3rd attempts, respectively, 29-37 s for further attempts). CONCLUSION: FAST may be considered as a possible new minimally invasive surfactant therapy technique for neonates ≥28 weeks with mild respiratory distress syndrome.


Assuntos
Síndrome do Desconforto Respiratório do Recém-Nascido , Síndrome do Desconforto Respiratório , Recém-Nascido , Humanos , Tensoativos , Projetos Piloto , Estudos Prospectivos , Síndrome do Desconforto Respiratório do Recém-Nascido/tratamento farmacológico
8.
Biochem Pharmacol ; 73(6): 831-42, 2007 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-17188249

RESUMO

Nicotinamide (NAm) represents both a pharmacological agent known to express cell preserving and anti-inflammatory properties, and a useful investigational tool to elucidate cellular pathways regulating a wide range of cellular functions. We demonstrate in this study that exogenous NAm, when used at pharmacological doses, inhibits activation of primary murine B lymphocytes in response to multiple ligands. NAm appears to affect a membrane proximal event leading to MAPKs activation, a transduction pathway shared by multiple receptors including the antigen-specific B cell receptor, CD38, CD40 and TLR4 receptors. NAm inhibited phospho-ERK accumulation, and only marginally affected phospho-p38 and phospho-JNK induction upon BCR stimulation of naive B lymphocytes. Accordingly, NAm also affected the expression of known targets of the MAPK ERK pathway such as CD69 and cyclin D2. Based on a comparison with well-characterized pharmacological inhibitors, we suggest in this work that NAm may inhibit a post-translational modification mediated by a yet unidentified mono(ADP-ribose)transferase. Collectively, our observations indicate that in addition to its previously described effect on cells of the innate immune system, NAm is able to modulate the activity of B lymphocytes suggesting a potential role of this vitamin in regulating antibody-mediated autoimmune disorders.


Assuntos
Linfócitos B/efeitos dos fármacos , Ativação Linfocitária/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Niacinamida/farmacologia , 3-Iodobenzilguanidina/farmacologia , Adenosina Difosfato Ribose/metabolismo , Animais , Formação de Anticorpos/efeitos dos fármacos , Antígenos CD/análise , Antígenos de Diferenciação de Linfócitos T/análise , Linfócitos B/imunologia , Cálcio/metabolismo , Feminino , Lectinas Tipo C , Camundongos , Camundongos Endogâmicos BALB C , Receptores de Antígenos de Linfócitos B
9.
Nucleic Acids Res ; 32(6): e56, 2004 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-15054124

RESUMO

Amplification of a cDNA product by quantitative PCR (qPCR) is monitored by a fluorescent signal proportional to the amount of produced amplicon. The qPCR amplification curve usually displays an exponential phase followed by a non-exponential phase, ending with a plateau. Contrary to prevalent interpretation, we demonstrate that under standard qPCR conditions, the plateau can be explained by depletion of the probe through Taq polymerase- catalysed hydrolysis. Knowing the probe concentration and the fluorescence measured at the plateau, a specific fluorescence can thus be calculated. As far as probe hydrolysis quantitatively reflects amplicon synthesis, this, in turn, makes it possible to convert measured fluorescence levels in the exponential phase into concentrations of produced amplicon. It follows that the absolute target cDNA concentration initially engaged in the qPCR can be directly estimated from the fluorescence data, with no need to refer to any calibration with known concentrations of target DNA.


Assuntos
DNA Complementar/análise , DNA Complementar/genética , Reação em Cadeia da Polimerase/métodos , Animais , Calibragem , Fluorescência , Fator de Crescimento Insulin-Like I/genética , Camundongos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase/normas , Padrões de Referência , Reprodutibilidade dos Testes , Glândula Tireoide/metabolismo , Fatores de Tempo
10.
Adv Biol Regul ; 53(1): 39-50, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22981169

RESUMO

Mice genetically-deficient for the B isoform of the inositol 1,4,5-trisphosphate 3-kinase (or Itpkb) have a severe defect in thymocytes differentiation and thus lack peripheral T cells. In order to study the functional role of Itpkb in peripheral T cells, we constructed a new mouse where a transgene encoding mouse Itpkb is specifically and transiently expressed in thymocytes of Itpkb(-)(/)(-) mice. This allows a partial rescue of mature thymocyte/T cell differentiation and thus the functional characterization of peripheral T cells lacking Itpkb. We show here that Itpkb(-)(/)(-) CD4(+) and CD8(+) peripheral T cells present important functional alterations. Indeed, an increased activated/memory phenotype as well as a decreased proliferative capacity and survival were detected in these T cells. These Itpkb-deficient peripheral T cells have also an increased capacity to secrete cytokines upon stimulation. Together, our present results define the important role of Itpkb in peripheral mature T cell fate and function in mouse, suggesting a potential role for Itpkb in autoimmunity.


Assuntos
Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Timócitos/metabolismo , Animais , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Diferenciação Celular , Proliferação de Células , Sobrevivência Celular , Células Cultivadas , Citocinas/biossíntese , Citocinas/imunologia , Expressão Gênica , Memória Imunológica , Camundongos , Camundongos Knockout , Fosfotransferases (Aceptor do Grupo Álcool)/deficiência , Fosfotransferases (Aceptor do Grupo Álcool)/imunologia , Transdução de Sinais , Timócitos/citologia , Timócitos/imunologia
11.
Adv Enzyme Regul ; 51(1): 66-73, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21035494

RESUMO

In mammals, Ins(1,4,5)P3, the well known calcium mobilization messenger, is phosphorylated in the cytosol at the 3-position of the inositol ring to yield Ins(1,3,4,5)P4 by Ins(1,4,5)P3 3-kinases A, B and C isoforms as well as by inositol polyphosphate multikinase (Ipmk). Studies in gene-deficient mice have revealed that these enzymes and Ins(1,3,4,5)P4, their reaction product, play essential role in multiple physiological processes, ranging from synaptic plasticity, hematopoietic cell survival, development and function, to mRNA export, transcriptional regulation and chromatin remodelling. Rather than to provide an unique and "universal" mechanism of Ins(1,3,4,5)P4 action, these studies in genetically-modified mice point for a role of this inositide in the control of calcium mobilization, of the subcellular localisation of PH domain-containing target proteins, and of higher inositol phosphate production. Mice deficient for the B isoform of inositol 1,4,5-trisphosphate 3-kinase (Itpkb) develop profound alterations in T and B cells as well as in neutrophils and mast cells. Our recent studies indicate that the 3-kinase Itpkb and Ins(1,3,4,5)P4 are important for the survival of naïve mature B cells and the control of proapoptotic Bim protein expression, rather than for the control of B cell transition from one developmental stage to another. They also suggest that Itpkb is an important component in the control of B cell anergy.


Assuntos
Linfócitos B/fisiologia , Sobrevivência Celular/fisiologia , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Animais , Cálcio/metabolismo , Humanos , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Transdução de Sinais/fisiologia
12.
Immunobiology ; 216(1-2): 103-9, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-20452702

RESUMO

Inositol 1,4,5-trisphosphate 3-kinase B (or Itpkb) and inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4), its reaction product, play an important role in the control of B lymphocyte fate and function in vivo. In order to investigate the fine mechanisms of Itpkb and Ins(1,3,4,5)P4 action in B cells, we crossed Itpkb(-/-) mice with transgenic mice expressing a 3-83µÎ´ B cell receptor (BCR) specific for membrane-bound MHC-I H2-K(b) and H2-K(k) molecules. On a non-deleting H2-K(d) genetic background, we show that Itpkb is important for the control of Bim protein expression and B cell survival rather than for the control of B cell development from one stage to another. Analyses of cell surface markers expression, proapoptotic Bim protein expression, in vitro survival and in vivo turnover demonstrated that BCR transgenic Itpkb(-/-) B cells exhibit an anergic phenotype with the notable exception of their enhanced antigen-induced calcium signalling. On a deleting H2-K(b) genetic background, we show that Itpkb is not essential for BCR editing or negative selection. These data establish Itpkb as an important regulator of B cell survival and anergy in vivo.


Assuntos
Linfócitos B/metabolismo , Fosfatos de Inositol/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Animais , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Linfócitos B/citologia , Linfócitos B/imunologia , Proteína 11 Semelhante a Bcl-2 , Sinalização do Cálcio/genética , Sobrevivência Celular/genética , Sobrevivência Celular/imunologia , Células Cultivadas , Anergia Clonal/genética , Antígenos H-2/imunologia , Fosfatos de Inositol/imunologia , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Camundongos Transgênicos , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Fosfotransferases (Aceptor do Grupo Álcool)/imunologia , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Receptores de Antígenos de Linfócitos B/genética
13.
Proc Natl Acad Sci U S A ; 104(35): 13978-83, 2007 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-17709751

RESUMO

The contribution of the B isoform of inositol 1,4,5-trisphosphate [Ins(1,4,5)P(3)] 3-kinase (or Itpkb) and inositol 1,3,4,5-tetrakisphosphate [Ins(1,3,4,5)P(4)], its reaction product, to B cell function and development remains unknown. Here, we show that mice deficient in Itpkb have defects in B cell survival leading to specific and intrinsic developmental alterations in the B cell lineage and antigen unresponsiveness in vivo. The decreased B cell survival is associated with a decreased phosphorylation of Erk1/2 and increased Bim gene expression. B cell survival, development, and antigen responsiveness are normalized in parallel to reduced expression of Bim in Itpkb(-/-) Bim(+/-) mice. Analysis of the signaling pathway downstream of Itpkb revealed that Ins(1,3,4,5)P(4) regulates subcellular distribution of Rasa3, a Ras GTPase-activating protein acting as an Ins(1,3,4,5)P(4) receptor. Together, our results indicate that Itpkb and Ins(1,3,4,5)P(4) mediate a survival signal in B cells via a Rasa3-Erk signaling pathway controlling proapoptotic Bim gene expression.


Assuntos
Proteínas Reguladoras de Apoptose/genética , Linfócitos B/citologia , Linfócitos B/fisiologia , Fosfatos de Inositol/farmacologia , Proteínas de Membrana/genética , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Proteínas Proto-Oncogênicas/genética , Animais , Apoptose , Proteínas Reguladoras de Apoptose/deficiência , Subpopulações de Linfócitos B/citologia , Subpopulações de Linfócitos B/imunologia , Subpopulações de Linfócitos B/fisiologia , Linfócitos B/imunologia , Proteína 11 Semelhante a Bcl-2 , Medula Óssea/imunologia , Sobrevivência Celular , Regulação da Expressão Gênica , Imunoglobulina D/análise , Imunoglobulina M/análise , Proteínas de Membrana/deficiência , Camundongos , Camundongos Knockout , Fosfotransferases (Aceptor do Grupo Álcool)/deficiência , Proteínas Proto-Oncogênicas/deficiência , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Baço/imunologia
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