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1.
Pediatrics ; 145(2)2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31988171

RESUMO

BACKGROUND AND OBJECTIVES: Clinicians are urged to optimize communication with families, generally without empirical practical recommendations. The objective of this study was to identify core behaviors associated with good communication during and after an unsuccessful resuscitation, including parental perspectives. METHODS: Clinicians from different backgrounds participated in a standardized, videotaped, simulated neonatal resuscitation in the presence of parent actors. The infant remained pulseless; participants communicated with the parent actors before, during, and after discontinuing resuscitation. Twenty-one evaluators with varying expertise (including 6 bereaved parents) viewed the videos. They were asked to score clinician-parent communication and identify the top communicators. In open-ended questions, they were asked to describe 3 aspects that were well done and 3 that were not. Answers to open-ended questions were coded for easily reproducible behaviors. All the videos were then independently reviewed to evaluate whether these behaviors were present. RESULTS: Thirty-one participants' videos were examined by 21 evaluators (651 evaluations). Parents and actors agreed with clinicians 81% of the time about what constituted optimal communication. Good communicators were more likely to introduce themselves, use the infant's name, acknowledge parental presence, prepare the parents (for the resuscitation, then death), stop resuscitation without asking parents, clearly mention death, provide or enable proximity (clinician-parent, infant-parent, clinician-infant, mother-father), sit down, decrease guilt, permit silence, and have knowledge about procedures after death. Consistently, clinicians who displayed such behaviors had evaluations >9 out of 10 and were all ranked top 10 communicators. CONCLUSIONS: During a neonatal end-of-life scenario, many simple behaviors, identified by parents and providers, can optimize clinician-parent communication.


Assuntos
Comunicação , Neonatologia , Pais , Ressuscitação/educação , Treinamento por Simulação/métodos , Assistência Terminal , Técnicas de Observação do Comportamento/ética , Técnicas de Observação do Comportamento/métodos , Pessoal de Saúde , Humanos , Internato e Residência , Idioma , Futilidade Médica , Treinamento por Simulação/ética , Gravação em Vídeo
3.
Cochrane Database Syst Rev ; 2: CD005389, 2017 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-28176308

RESUMO

BACKGROUND: Fluid restriction is often recommended as part of the management of infants with early or established bronchopulmonary dysplasia (BPD). OBJECTIVES: To determine whether fluid restriction as part of the therapeutic intervention for early or established BPD improves clinical outcomes. SEARCH METHODS: We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 1) in the Cochrane Library (searched 16 February 2016), MEDLINE via PubMed (1966 to 16 February 2016), Embase (1980 to 16 February 2016), and CINAHL (1982 to 16 February 2016). We also searched clinical trials' databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. SELECTION CRITERIA: Prospective randomised clinical trials comparing two distinct fluid administration volumes in preterm infants with early or established BPD. DATA COLLECTION AND ANALYSIS: We used the standard methods of Cochrane Neonatal. For the included trial, we extracted data and assessed the risk of bias, and used GRADE methods to assess the quality of the evidence. The outcomes considered in this review are effects on mortality or requirement for oxygen at 36 weeks' postmenstrual age (primary outcome measure), the duration of supplemental oxygen therapy, proportion of infants discharged from hospital on oxygen, duration of assisted ventilation, duration of hospitalisation, weight gain, feeding tolerance, apnoea, necrotizing enterocolitis, renal dysfunction or nephrocalcinosis, lung mechanics, and use of diuretic therapy (secondary outcome measures). MAIN RESULTS: One trial was found, including 60 preterm infants at 28 days of age with persistent oxygen requirements. Infants were randomised to either 180 mL/kg/day of standard formula or 145 mL/kg/day of concentrated formula. This single study did not provide data regarding our primary outcome. No effects of the intervention were found on any of our secondary outcomes. The quality of the evidence from this study was graded low. AUTHORS' CONCLUSIONS: There is no evidence to support the practice of fluid restriction in infants with early or established BPD.


Assuntos
Displasia Broncopulmonar/terapia , Hidratação/métodos , Apneia/epidemiologia , Doença Crônica , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Tempo de Internação/estatística & dados numéricos , Pneumopatias/terapia , Oxigenoterapia , Ensaios Clínicos Controlados Aleatórios como Assunto , Respiração Artificial/estatística & dados numéricos , Aumento de Peso
4.
Cochrane Database Syst Rev ; 1: CD000509, 2017 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-28045472

RESUMO

BACKGROUND: Inhaled nitric oxide (iNO) is effective in term infants with hypoxic respiratory failure. The pathophysiology of respiratory failure and the potential risks of iNO differ substantially in preterm infants, necessitating specific study in this population. OBJECTIVES: To determine effects of treatment with inhaled nitric oxide (iNO) on death, bronchopulmonary dysplasia (BPD), intraventricular haemorrhage (IVH) or other serious brain injury and on adverse long-term neurodevelopmental outcomes in preterm newborn infants with hypoxic respiratory failure.Owing to substantial variation in study eligibility criteria, which decreases the utility of an overall analysis, we divided participants post hoc into three groups: (1) infants treated over the first three days of life because of defects in oxygenation, (2) preterm infants with evidence of pulmonary disease treated routinely with iNO and (3) infants treated later (after three days of age) because of elevated risk of BPD. SEARCH METHODS: We used standard methods of the Cochrane Neonatal Review Group. We searched MEDLINE, Embase, Healthstar and the Cochrane Central Register of Controlled Trials in the Cochrane Library through January 2016. We also searched the abstracts of the Pediatric Academic Societies. SELECTION CRITERIA: Eligible for inclusion were randomised and quasi-randomised studies in preterm infants with respiratory disease that compared effects of iNO gas versus control, with or without placebo. DATA COLLECTION AND ANALYSIS: We used standard methods of the Cochrane Neonatal Review Group and applied the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess the quality of evidence. MAIN RESULTS: We found 17 randomised controlled trials of iNO therapy in preterm infants. We grouped these trials post hoc into three categories on the basis of entry criteria: treatment during the first three days of life for impaired oxygenation, routine use in preterm babies along with respiratory support and later treatment for infants at increased risk for bronchopulmonary dysplasia (BPD). We performed no overall analyses.Eight trials providing early rescue treatment for infants on the basis of oxygenation criteria demonstrated no significant effect of iNO on mortality or BPD (typical risk ratio (RR) 0.94, 95% confidence interval (CI) 0.87 to 1.01; 958 infants). Four studies examining routine use of iNO in infants with pulmonary disease reported no significant reduction in death or BPD (typical RR 0.94, 95% CI 0.87 to 1.02; 1924 infants), although this small effect approached significance. Later treatment with iNO based on risk of BPD (three trials) revealed no significant benefit for this outcome in analyses of summary data (typical RR 0.92, 95% CI 0.85 to 1.01; 1075 infants).Investigators found no clear effect of iNO on the frequency of all grades of IVH nor severe IVH. Early rescue treatment was associated with a non-significant 20% increase in severe IVH.We found no effect on the incidence of neurodevelopmental impairment. AUTHORS' CONCLUSIONS: iNO does not appear to be effective as rescue therapy for the very ill preterm infant. Early routine use of iNO in preterm infants with respiratory disease does not prevent serious brain injury or improve survival without BPD. Later use of iNO to prevent BPD could be effective, but current 95% confidence intervals include no effect; the effect size is likely small (RR 0.92) and requires further study.


Assuntos
Doenças do Prematuro/terapia , Óxido Nítrico/administração & dosagem , Insuficiência Respiratória/terapia , Vasodilatadores/administração & dosagem , Administração por Inalação , Displasia Broncopulmonar/mortalidade , Displasia Broncopulmonar/prevenção & controle , Hemorragia Cerebral/epidemiologia , Hemorragia Cerebral/prevenção & controle , Humanos , Incidência , Recém-Nascido , Recém-Nascido Prematuro , Doenças do Prematuro/prevenção & controle , Ensaios Clínicos Controlados Aleatórios como Assunto , Terapia de Salvação
5.
Cochrane Database Syst Rev ; 1: CD000399, 2017 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-28056166

RESUMO

BACKGROUND: Nitric oxide (NO) is a major endogenous regulator of vascular tone. Inhaled nitric oxide (iNO) gas has been investigated as treatment for persistent pulmonary hypertension of the newborn. OBJECTIVES: To determine whether treatment of hypoxaemic term and near-term newborn infants with iNO improves oxygenation and reduces rate of death and use of extracorporeal membrane oxygenation (ECMO), or affects long-term neurodevelopmental outcomes. SEARCH METHODS: We used the standard search strategy of the Cochrane Neonatal Review Group to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 1), MEDLINE via PubMed (1966 to January 2016), Embase (1980 to January 2016) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to January 2016). We searched clinical trials databases, conference proceedings and reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. We contacted the principal investigators of studies published as abstracts to ascertain the necessary information. SELECTION CRITERIA: Randomised studies of iNO in term and near-term infants with hypoxic respiratory failure, with clinically relevant outcomes, including death, use of ECMO and oxygenation. DATA COLLECTION AND ANALYSIS: We analysed trial reports to assess methodological quality using the criteria of the Cochrane Neonatal Review Group. We tabulated mortality, oxygenation, short-term clinical outcomes (particularly use of ECMO) and long-term developmental outcomes. STATISTICS: For categorical outcomes, we calculated typical estimates for risk ratios and risk differences. For continuous variables, we calculated typical estimates for weighted mean differences. We used 95% confidence intervals and assumed a fixed-effect model for meta-analysis. MAIN RESULTS: We found 17 eligible randomised controlled studies that included term and near-term infants with hypoxia.Ten trials compared iNO versus control (placebo or standard care without iNO) in infants with moderate or severe severity of illness scores (Ninos 1996; Roberts 1996; Wessel 1996; Davidson 1997; Ninos 1997; Mercier 1998; Christou 2000; Clark 2000; INNOVO 2007; Liu 2008). Mercier 1998 compared iNO versus control but allowed back-up treatment with iNO for infants who continued to satisfy the same criteria for severity of illness after two hours. This trial enrolled both preterm and term infants but reported most results separately for the two groups. Ninos 1997 studied only infants with congenital diaphragmatic hernia.One trial compared iNO versus high-frequency ventilation (Kinsella 1997).Six trials enrolled infants with moderate severity of illness scores (oxygenation index (OI) or alveolar-arterial oxygen difference (A-aDO2)) and randomised them to immediate iNO treatment or iNO treatment only after deterioration to more severe criteria (Barefield 1996; Day 1996; Sadiq 1998; Cornfield 1999; Konduri 2004; Gonzalez 2010).Inhaled nitric oxide appears to have improved outcomes in hypoxaemic term and near-term infants by reducing the incidence of the combined endpoint of death or use of ECMO (high-quality evidence). This reduction was due to a reduction in use of ECMO (with number needed to treat for an additional beneficial outcome (NNTB) of 5.3); mortality was not affected. Oxygenation was improved in approximately 50% of infants receiving iNO. The OI was decreased by a (weighted) mean of 15.1 within 30 to 60 minutes after the start of therapy, and partial pressure of arterial oxygen (PaO2) was increased by a mean of 53 mmHg. Whether infants had clear echocardiographic evidence of persistent pulmonary hypertension of the newborn (PPHN) did not appear to affect response to iNO. Outcomes of infants with diaphragmatic hernia were not improved; outcomes were slightly, but not significantly, worse with iNO (moderate-quality evidence).Infants who received iNO at less severe criteria did not have better clinical outcomes than those who were enrolled but received treatment only if their condition deteriorated. Fewer of the babies who received iNO early satisfied late treatment criteria, showing that earlier iNO reduced progression of the disease but did not further decrease mortality nor the need for ECMO (moderate-quality evidence). Incidence of disability, incidence of deafness and infant development scores were all similar between tested survivors who received iNO and those who did not. AUTHORS' CONCLUSIONS: Inhaled nitric oxide is effective at an initial concentration of 20 ppm for term and near-term infants with hypoxic respiratory failure who do not have a diaphragmatic hernia.


Assuntos
Óxido Nítrico/uso terapêutico , Insuficiência Respiratória/tratamento farmacológico , Vasodilatadores/uso terapêutico , Administração por Inalação , Oxigenação por Membrana Extracorpórea , Hérnia Diafragmática/complicações , Ventilação de Alta Frequência , Humanos , Recém-Nascido , Óxido Nítrico/administração & dosagem , Ensaios Clínicos Controlados Aleatórios como Assunto , Insuficiência Respiratória/mortalidade , Nascimento a Termo , Vasodilatadores/administração & dosagem
6.
JMIR Res Protoc ; 5(1): e26, 2016 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-26888076

RESUMO

BACKGROUND: Helping trainees develop appropriate clinical reasoning abilities is a challenging goal in an environment where clinical situations are marked by high levels of complexity and unpredictability. The benefit of simulation-based education to assess clinical reasoning skills has rarely been reported. More specifically, it is unclear if clinical reasoning is better acquired if the instructor's input occurs entirely after or is integrated during the scenario. Based on educational principles of the dual-process theory of clinical reasoning, a new simulation approach called simulation with iterative discussions (SID) is introduced. The instructor interrupts the flow of the scenario at three key moments of the reasoning process (data gathering, integration, and confirmation). After each stop, the scenario is continued where it was interrupted. Finally, a brief general debriefing ends the session. System-1 process of clinical reasoning is assessed by verbalization during management of the case, and System-2 during the iterative discussions without providing feedback. OBJECTIVE: The aim of this study is to evaluate the effectiveness of Simulation with Iterative Discussions versus the classical approach of simulation in developing reasoning skills of General Pediatrics and Neonatal-Perinatal Medicine residents. METHODS: This will be a prospective exploratory, randomized study conducted at Sainte-Justine hospital in Montreal, Qc, between January and March 2016. All post-graduate year (PGY) 1 to 6 residents will be invited to complete one SID or classical simulation 30 minutes audio video-recorded complex high-fidelity simulations covering a similar neonatology topic. Pre- and post-simulation questionnaires will be completed and a semistructured interview will be conducted after each simulation. Data analyses will use SPSS and NVivo softwares. RESULTS: This study is in its preliminary stages and the results are expected to be made available by April, 2016. CONCLUSIONS: This will be the first study to explore a new simulation approach designed to enhance clinical reasoning. By assessing more closely reasoning processes throughout a simulation session, we believe that Simulation with Iterative Discussions will be an interesting and more effective approach for students. The findings of the study will benefit medical educators, education programs, and medical students.

7.
Am J Med Genet A ; 164A(1): 208-12, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24352915

RESUMO

Congenital diaphragmatic hernia (CDH) has an incidence of around 1/3,000 births. The pathogenesis of this developmental anomaly remains largely unknown and the description of small chromosomal imbalances in cases of CDH is of major interest for the identification of candidate genes. We report on a tandem 4q31.23 triplication encompassing the EDNRA gene identified by array-CGH in a male presenting an isolated left postero-lateral CDH. This copy number variation was inherited from the asymptomatic father, carrier of a size-identical duplication. We demonstrate that EDNRA mRNA is over-expressed in the proband in blood tissue. Consistent with the expression of EDNRA in the developing diaphragm and the observation that the endothelin system is up-regulated in human and animal models of CDH, we conclude that the EDNRA triplication may be the cause of CDH in our patient.


Assuntos
Hérnias Diafragmáticas Congênitas/etiologia , Cromossomos Humanos Par 4 , Hibridização Genômica Comparativa , Hérnias Diafragmáticas Congênitas/diagnóstico , Humanos , Recém-Nascido , Masculino , Fenótipo , Receptor de Endotelina A/genética , Trissomia
8.
Arch Cardiovasc Dis ; 106(3): 169-77, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23582679

RESUMO

The main cause of pulmonary hypertension in newborn babies results from the failure of the pulmonary circulation to dilate at birth, termed 'persistent pulmonary hypertension of the newborn' (PPHN). This syndrome is characterized by sustained elevation of pulmonary vascular resistance, causing extrapulmonary right-to-left shunting of blood across the ductus arteriosus and foramen ovale and severe hypoxaemia. It can also lead to life-threatening circulatory failure. There are many controversial and unresolved issues regarding the pathophysiology of PPHN, and these are discussed. PPHN is generally associated with factors such as congenital diaphragmatic hernia, birth asphyxia, sepsis, meconium aspiration and respiratory distress syndrome. However, the perinatal environment-exposure to nicotine and certain medications, maternal obesity and diabetes, epigenetics, painful stimuli and birth by Caesarean section-may also affect the maladaptation of the lung circulation at birth. In infants with PPHN, it is important to optimize circulatory function. Suggested management strategies for PPHN include: avoidance of environmental factors that worsen PPHN (e.g. noxious stimuli, lung overdistension); adequate lung recruitment and alveolar ventilation; inhaled nitric oxide (or sildenafil, if inhaled nitric oxide is not available); haemodynamic assessment; appropriate fluid and cardiovascular resuscitation and inotropic and vasoactive agents.


Assuntos
Meio Ambiente , Síndrome da Persistência do Padrão de Circulação Fetal/fisiopatologia , Adaptação Fisiológica , Fármacos Cardiovasculares/uso terapêutico , Cesárea/efeitos adversos , Oxigenação por Membrana Extracorpórea , Feminino , Hemodinâmica , Humanos , Recém-Nascido , Exposição Materna , Dor/complicações , Síndrome da Persistência do Padrão de Circulação Fetal/diagnóstico , Síndrome da Persistência do Padrão de Circulação Fetal/etiologia , Síndrome da Persistência do Padrão de Circulação Fetal/terapia , Gravidez , Circulação Pulmonar , Respiração Artificial , Fatores de Risco , Estresse Fisiológico , Poluição por Fumaça de Tabaco/efeitos adversos , Resultado do Tratamento
9.
J Pediatr ; 162(6): 1133-7, 1137.e1, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23312684

RESUMO

OBJECTIVE: To compare breathing patterns and lung function in the supine, lateral, and prone positions in oxygen-dependent preterm infants. STUDY DESIGN: Respiratory function in preterm infants receiving nasal continous positive airway pressure therapy for mild respiratory failure was evaluated by respiratory inductive plethysmography. Infants were randomized to supine, left lateral, and prone positions for 3 hours. A nest provided a semiflexed posture for the infants placed in the left lateral position, similar to the in utero position. Tidal volume (Vt), phase angle between abdominal and thoracic movements, rib cage contribution to Vt, and dynamic elevation of end-expiratory lung volume were measured. RESULTS: Fraction of inspired O2 was similar in the 3 positions for 19 infants (mean gestational age, 27±2 weeks; mean birth weight, 950±150 g; mean postnatal age, 17±5 days). However, arterial O2 saturation and Vt were higher in the left lateral and prone positions than in the supine position (P<.05). The phase angle between abdominal and thoracic movements was lower and rib cage contribution to Vt was higher in the left lateral and prone positions than in the supine position (P<.05). Dynamic elevation of end-expiratory lung volume was greater in the supine position than in the left lateral and prone positions (P<.05). CONCLUSION: In oxygen-dependent preterm infants, both the left lateral and prone positions improve lung function by optimizing breathing strategy. In the neonatal intensive care unit, the left lateral position can be used as an alternative to the prone position for mild respiratory failure.


Assuntos
Doenças do Prematuro/fisiopatologia , Pulmão/fisiopatologia , Posicionamento do Paciente , França , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Unidades de Terapia Intensiva Neonatal , Pletismografia , Respiração , Testes de Função Respiratória
10.
J Pediatr ; 161(3): 404-8, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22534152

RESUMO

OBJECTIVE: To determine the hemodynamic impact of fluid restriction in preterm newborns with significant patent ductus arteriosus. STUDY DESIGN: Newborns ≥24 and <32 weeks' gestational age with significant patent ductus arteriosus were eligible for this prospective multicenter observational study. We recorded hemodynamic and Doppler echocardiographic variables before and 24 hours after fluid restriction. RESULTS: Eighteen newborns were included (gestational age 24.8 ± 1.1 weeks, birth weight 850 ± 180 g). Fluid intake was decreased from 145 ± 15 to 108 ± 10 mL/kg/d. Respiratory variables, fraction of inspired oxygen, blood gas values, ductus arteriosus diameter, blood flow-velocities in ductus arteriosus, in the left pulmonary artery and in the ascending aorta, and the left atrial/aortic root ratio were unchanged after fluid restriction. Although systemic blood pressure did not change, blood flow in the superior vena cava decreased from 105 ± 40 to 61 ± 25 mL/kg/min (P < .001). The mean blood flow-velocity in the superior mesenteric artery was lower 24 hours after starting fluid restriction. CONCLUSIONS: Our results do not support the hypothesis that fluid restriction has beneficial effects on pulmonary or systemic hemodynamics in preterm newborns.


Assuntos
Permeabilidade do Canal Arterial/fisiopatologia , Doenças do Prematuro/fisiopatologia , Água/administração & dosagem , Ecocardiografia Doppler , Hemodinâmica , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Pulmão/fisiopatologia , Estudos Prospectivos , Artéria Pulmonar/fisiopatologia , Fluxo Sanguíneo Regional/fisiologia , Veia Cava Superior/fisiopatologia
11.
Eur J Med Genet ; 54(5): e525-7, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21782985

RESUMO

Congenital diaphragmatic hernia (CDH) has an incidence of around 1/3000 births. Chromosomal anomalies constitute an important etiology for non-isolated CDH, and may participate to the identification of candidate genes for diaphragm development. We report on a microduplication identified by array-CGH (comparative genomic hybridization) including five contiguous genes (OPHN1, YIPF6, STARD8, EFNB1 and PJA1) and arising de novo in a male presenting a congenital diaphragmatic hernia (CDH). Our case is the second report of EFNB1 duplication associated with CDH in a male patient, supporting its implication sensitive to gene dosage in diaphragm development.


Assuntos
Efrina-B1/genética , Hérnias Diafragmáticas Congênitas , Transtornos dos Cromossomos Sexuais/genética , Trissomia/genética , Bandeamento Cromossômico , Cromossomos Humanos X/genética , Hibridização Genômica Comparativa , Dosagem de Genes , Hérnia Diafragmática/genética , Humanos , Hibridização in Situ Fluorescente , Lactente , Masculino , Fenótipo , Aberrações dos Cromossomos Sexuais
12.
Hum Mutat ; 32(4): 476-83, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21305656

RESUMO

Mutations in the electrogenic Cl(-)/H(+) exchanger ClC-5 gene CLCN5 are frequently associated with Dent disease, an X-linked recessive disorder affecting the proximal tubules. Here, we investigate the consequences in Xenopus laevis oocytes and in HEK293 cells of nine previously reported, pathogenic, missense mutations of ClC-5, most of them which are located in regions forming the subunit interface. Two mutants trafficked normally to the cell surface and to early endosomes, and displayed complex glycosylation at the cell surface like wild-type ClC-5, but exhibited reduced currents. Three mutants displayed improper N-glycosylation, and were nonfunctional due to being retained and degraded at the endoplasmic reticulum. Functional characterization of four mutants allowed us to identify a novel mechanism leading to ClC-5 dysfunction in Dent disease. We report that these mutant proteins were delayed in their processing, and that the stability of their complex glycosylated form was reduced, causing lower cell surface expression. The early endosome distribution of these mutants was normal. Half of these mutants displayed reduced currents, whereas the other half showed abolished currents. Our study revealed distinct cellular mechanisms accounting for ClC-5 loss of function in Dent disease.


Assuntos
Canais de Cloreto/genética , Doença de Dent/genética , Mutação , Sequência de Aminoácidos , Animais , Células Cultivadas , Canais de Cloreto/metabolismo , Doença de Dent/metabolismo , Células HEK293 , Humanos , Túbulos Renais Proximais/metabolismo , Dados de Sequência Molecular , Oócitos/metabolismo , Alinhamento de Sequência , Xenopus laevis
13.
Kidney Int ; 76(9): 999-1005, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19657328

RESUMO

Dent's disease is an X-linked recessive disorder affecting the proximal tubules and is frequently associated with mutations in CLCN5, which encodes the electrogenic chloride-proton exchanger ClC-5. To better understand the functional consequences of CLCN5 mutations in this disease, we screened four newly identified missense mutations (G179D, S203L, G212A, L469P), one new nonsense mutation (R718X), and three known mutations (L200R, C219R, and C221R), in Xenopus laevis oocytes and HEK293 cells expressing either wild-type or mutant exchanger. A type-I mutant (G212A) trafficked normally to the cell surface and to early endosomes, underwent complex glycosylation at the cell surface like wild-type ClC-5, but exhibited significant reductions in outwardly rectifying ion currents. The type-II mutants (G179D, L200R, S203L, C219R, C221R, L469P, and R718X) were improperly N-glycosylated and were non-functional due to retention in the endoplasmic reticulum. Thus these mutations have distinct mechanisms by which they could impair ClC-5 function in Dent's disease.


Assuntos
Canais de Cloreto/genética , Cloretos/metabolismo , Códon sem Sentido , Nefropatias/genética , Túbulos Renais Proximais/metabolismo , Mutação de Sentido Incorreto , Sequência de Aminoácidos , Animais , Transporte Biológico/genética , Linhagem Celular , Membrana Celular/metabolismo , Criança , Pré-Escolar , Canais de Cloreto/metabolismo , Retículo Endoplasmático/metabolismo , Endossomos/metabolismo , Predisposição Genética para Doença , Glicosilação , Humanos , Lactente , Nefropatias/metabolismo , Potenciais da Membrana , Microinjeções , Dados de Sequência Molecular , Fenótipo , Processamento de Proteína Pós-Traducional , Transporte Proteico , Fatores de Risco , Transfecção , Xenopus laevis
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