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1.
Lancet Oncol ; 24(9): 978-988, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37433316

RESUMO

BACKGROUND: Paediatric early warning systems (PEWS) aid in the early identification of clinical deterioration events in children admitted to hospital. We aimed to investigate the effect of PEWS implementation on mortality due to clinical deterioration in children with cancer in 32 resource-limited hospitals across Latin America. METHODS: Proyecto Escala de Valoración de Alerta Temprana (Proyecto EVAT) is a quality improvement collaborative to implement PEWS in hospitals providing childhood cancer care. In this prospective, multicentre cohort study, centres joining Proyecto EVAT and completing PEWS implementation between April 1, 2017, and May 31, 2021, prospectively tracked clinical deterioration events and monthly inpatient-days in children admitted to hospital with cancer. De-identified registry data reported between April 17, 2017, and Nov 30, 2021, from all hospitals were included in analyses; children with limitations on escalation of care were excluded. The primary outcome was clinical deterioration event mortality. Incidence rate ratios (IRRs) were used to compare clinical deterioration event mortality before and after PEWS implementation; multivariable analyses assessed the correlation between clinical deterioration event mortality and centre characteristics. FINDINGS: Between April 1, 2017, and May 31, 2021, 32 paediatric oncology centres from 11 countries in Latin America successfully implemented PEWS through Proyecto EVAT; these centres documented 2020 clinical deterioration events in 1651 patients over 556 400 inpatient-days. Overall clinical deterioration event mortality was 32·9% (664 of 2020 events). The median age of patients with clinical deterioration events was 8·5 years (IQR 3·9-13·2), and 1095 (54·2%) of 2020 clinical deterioration events were reported in male patients; data on race or ethnicity were not collected. Data were reported per centre for a median of 12 months (IQR 10-13) before PEWS implementation and 18 months (16-18) after PEWS implementation. The mortality rate due to a clinical deterioration event was 1·33 events per 1000 patient-days before PEWS implementation and 1·09 events per 1000 patient-days after PEWS implementation (IRR 0·82 [95% CI 0·69-0·97]; p=0·021). In the multivariable analysis of centre characteristics, higher clinical deterioration event mortality rates before PEWS implementation (IRR 1·32 [95% CI 1·22-1·43]; p<0·0001), being a teaching hospital (1·18 [1·09-1·27]; p<0·0001), not having a separate paediatric haematology-oncology unit (1·38 [1·21-1·57]; p<0·0001), and having fewer PEWS omissions (0·95 [0·92-0·99]; p=0·0091) were associated with a greater reduction in clinical deterioration event mortality after PEWS implementation; no association was found with country income level (IRR 0·86 [95% CI 0·68-1·09]; p=0·22) or clinical deterioration event rates before PEWS implementation (1·04 [0·97-1·12]; p=0·29). INTERPRETATION: PEWS implementation was associated with reduced clinical deterioration event mortality in paediatric patients with cancer across 32 resource-limited hospitals in Latin America. These data support the use of PEWS as an effective evidence-based intervention to reduce disparities in global survival for children with cancer. FUNDING: American Lebanese Syrian Associated Charities, US National Institutes of Health, and Conquer Cancer Foundation. TRANSLATIONS: For the Spanish and Portuguese translations of the abstract see Supplementary Materials section.


Assuntos
Deterioração Clínica , Neoplasias , Criança , Humanos , Masculino , Pré-Escolar , Adolescente , Estudos de Coortes , Estudos Prospectivos , América Latina/epidemiologia , Neoplasias/terapia , Hospitais
2.
Cancer ; 128(22): 4004-4016, 2022 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-36161436

RESUMO

BACKGROUND: Pediatric early warning systems (PEWS) aid in the early identification of deterioration in hospitalized children with cancer; however, they are under-used in resource-limited settings. The authors use the knowledge-to-action framework to describe the implementation strategy for Proyecto Escala de Valoracion de Alerta Temprana (EVAT), a multicenter quality-improvement collaborative, to scale-up PEWS in pediatric oncology centers in Latin America. METHODS: Proyecto EVAT mentored participating centers through an adaptable implementation strategy to: (1) monitor clinical deterioration in children with cancer, (2) contextually adapt PEWS, (3) assess barriers to using PEWS, (4) pilot and implement PEWS, (5) monitor the use of PEWS, (6) evaluate outcomes, and (7) sustain PEWS. The implementation outcomes assessed included the quality of PEWS use, the time required for implementation, and global program impact. RESULTS: From April 2017 to October 2021, 36 diverse Proyecto EVAT hospitals from 13 countries in Latin America collectively managing more than 4100 annual new pediatric cancer diagnoses successfully implemented PEWS. The time to complete all program phases varied among centers, averaging 7 months (range, 3-13 months) from PEWS pilot to implementation completion. All centers ultimately implemented PEWS and maintained high-quality PEWS use for up to 18 months after implementation. Across the 36 centers, more than 11,100 clinicians were trained in PEWS, and more than 41,000 pediatric hospital admissions had PEWS used in their care. CONCLUSIONS: Evidence-based interventions like PEWS can be successfully scaled-up regionally basis using a systematic approach that includes a collaborative network, an adaptable implementation strategy, and regional mentorship. Lessons learned can guide future programs to promote the widespread adoption of effective interventions and reduce global disparities in childhood cancer outcomes. LAY SUMMARY: Pediatric early warning systems (PEWS) are clinical tools used to identify deterioration in hospitalized children with cancer; however, implementation challenges limit their use in resource-limited settings. Proyecto EVAT is a multicenter quality-improvement collaborative to implement PEWS in 36 pediatric oncology centers in Latin America. This is the first multicenter, multinational study reporting a successful implementation strategy (Proyecto EVAT) to regionally scale-up PEWS. The lessons learned from Proyecto EVAT can inform future programs to promote the adoption of clinical interventions to globally improve childhood cancer outcomes.


Assuntos
Oncologia , Neoplasias , Criança , Humanos , América Latina , Hospitais Pediátricos , Hospitalização
3.
Lancet Oncol ; 22(10): 1416-1426, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34454651

RESUMO

BACKGROUND: Previous studies have shown that children and adolescents with COVID-19 generally have mild disease. Children and adolescents with cancer, however, can have severe disease when infected with respiratory viruses. In this study, we aimed to understand the clinical course and outcomes of SARS-CoV-2 infection in children and adolescents with cancer. METHODS: We did a cohort study with data from 131 institutions in 45 countries. We created the Global Registry of COVID-19 in Childhood Cancer to capture de-identified data pertaining to laboratory-confirmed SARS-CoV-2 infections in children and adolescents (<19 years) with cancer or having received a haematopoietic stem-cell transplantation. There were no centre-specific exclusion criteria. The registry was disseminated through professional networks through email and conferences and health-care providers were invited to submit all qualifying cases. Data for demographics, oncological diagnosis, clinical course, and cancer therapy details were collected. Primary outcomes were disease severity and modification to cancer-directed therapy. The registry remains open to data collection. FINDINGS: Of 1520 submitted episodes, 1500 patients were included in the study between April 15, 2020, and Feb 1, 2021. 1319 patients had complete 30-day follow-up. 259 (19·9%) of 1301 patients had a severe or critical infection, and 50 (3·8%) of 1319 died with the cause attributed to COVID-19 infection. Modifications to cancer-directed therapy occurred in 609 (55·8%) of 1092 patients receiving active oncological treatment. Multivariable analysis revealed several factors associated with severe or critical illness, including World Bank low-income or lower-middle-income (odds ratio [OR] 5·8 [95% CI 3·8-8·8]; p<0·0001) and upper-middle-income (1·6 [1·2-2·2]; p=0·0024) country status; age 15-18 years (1·6 [1·1-2·2]; p=0·013); absolute lymphocyte count of 300 or less cells per mm3 (2·5 [1·8-3·4]; p<0·0001), absolute neutrophil count of 500 or less cells per mm3 (1·8 [1·3-2·4]; p=0·0001), and intensive treatment (1·8 [1·3-2·3]; p=0·0005). Factors associated with treatment modification included upper-middle-income country status (OR 0·5 [95% CI 0·3-0·7]; p=0·0004), primary diagnosis of other haematological malignancies (0·5 [0·3-0·8]; p=0·0088), the presence of one of more COVID-19 symptoms at the time of presentation (1·8 [1·3-2·4]; p=0·0002), and the presence of one or more comorbidities (1·6 [1·1-2·3]; p=0·020). INTERPRETATION: In this global cohort of children and adolescents with cancer and COVID-19, severe and critical illness occurred in one fifth of patients and deaths occurred in a higher proportion than is reported in the literature in the general paediatric population. Additionally, we found that variables associated with treatment modification were not the same as those associated with greater disease severity. These data could inform clinical practice guidelines and raise awareness globally that children and adolescents with cancer are at high-risk of developing severe COVID-19 illness. FUNDING: American Lebanese Syrian Associated Charities and the National Cancer Institute.


Assuntos
COVID-19 , Neoplasias , Adolescente , COVID-19/mortalidade , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Neoplasias/mortalidade , Fatores de Risco , SARS-CoV-2 , Índice de Gravidade de Doença
4.
Dev Biol ; 382(1): 172-85, 2013 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-23906841

RESUMO

Congenital hydrocephalus, the accumulation of excess cerebrospinal fluid (CSF) in the ventricles of the brain, affects one of every 1000 children born today, making it one of the most common human developmental disorders. Genetic causes of hydrocephalus are poorly understood in humans, but animal models suggest a broad genetic program underlying the regulation of CSF balance. In this study, the random integration of a transgene into the mouse genome led to the development of an early onset and rapidly progressive hydrocephalus. Juvenile hydrocephalus transgenic mice (Jhy(lacZ)) inherit communicating hydrocephalus in an autosomal recessive fashion with dilation of the lateral ventricles observed as early as postnatal day 1.5. Ventricular dilation increases in severity over time, becoming fatal at 4-8 weeks of age. The ependymal cilia lining the lateral ventricles are morphologically abnormal and reduced in number in Jhy(lacZ/lacZ) brains, and ultrastructural analysis revealed disorganization of the expected 9+2 microtubule pattern. Rather, the majority of Jhy(lacZ/lacZ) cilia develop axonemes with 9+0 or 8+2 microtubule structures. Disruption of an unstudied gene, 4931429I11Rik (now named Jhy) appears to underlie the hydrocephalus of Jhy(lacZ/lacZ) mice, and the Jhy transcript and protein are decreased in Jhy(lacZ/lacZ) mice. Partial phenotypic rescue was achieved in Jhy(lacZ/lacZ) mice by the introduction of a bacterial artificial chromosome (BAC) carrying 60-70% of the JHY protein coding sequence. Jhy is evolutionarily conserved from humans to basal vertebrates, but the predicted JHY protein lacks identifiable functional domains. Ongoing studies are directed at uncovering the physiological function of JHY and its role in CSF homeostasis.


Assuntos
Cílios/patologia , Deleção de Genes , Hidrocefalia/genética , Hidrocefalia/patologia , Microtúbulos/metabolismo , Proteínas/genética , Envelhecimento , Sequência de Aminoácidos , Animais , Sequência de Bases , Líquido Cefalorraquidiano/metabolismo , Cílios/metabolismo , Cílios/ultraestrutura , Progressão da Doença , Elementos Facilitadores Genéticos/genética , Epêndima/crescimento & desenvolvimento , Epêndima/metabolismo , Epêndima/patologia , Epêndima/ultraestrutura , Genes Reporter , Humanos , Hidrocefalia/líquido cefalorraquidiano , Camundongos , Camundongos Transgênicos , Microtúbulos/ultraestrutura , Dados de Sequência Molecular , Fenótipo , Proteínas/química , Proteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Síndrome , Transgenes/genética
5.
Cancer Med ; 12(10): 11878-11888, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37022012

RESUMO

BACKGROUND: The COVID-19 pandemic impacted healthcare delivery worldwide, including pediatric cancer care, with a disproportionate effect in resource-limited settings. This study evaluates its impact on existing quality improvement (QI) programs. METHODS: We conducted 71 semi-structured interviews of key stakeholders at five resource-limited pediatric oncology centers participating in a collaborative to implement Pediatric Early Warning System (PEWS). Interviews were conducted virtually using a structured interview guide, recorded, transcribed, and translated into English. Two coders developed a codebook of a priori and inductive codes and independently coded all transcripts, achieving a kappa of 0.8-0.9. Thematic analysis explored the impact of the pandemic on PEWS. RESULTS: All hospitals reported limitations in material resources, reduction in staffing, and impacts on patient care due to the pandemic. However, the impact on PEWS varied across centers. Identified factors that promoted or limited ongoing PEWS use included the availability of material resources needed for PEWS, staff turnover, PEWS training for staff, and the willingness of staff and hospital leaders to prioritize PEWS. Consequently, some hospitals were able to sustain PEWS; others halted or reduced PEWS use to prioritize other work. Similarly, the pandemic delayed plans at all hospitals to expand PEWS to other units. Several participants were hopeful for future expansion of PEWS post-pandemic. CONCLUSION: The COVID-19 pandemic created challenges for sustainability and scale of PEWS, an ongoing QI program, in these resource-limited pediatric oncology centers. Several factors mitigated these challenges and promoted ongoing PEWS use. These results can guide strategies to sustain effective QI interventions during future health crises.


Assuntos
COVID-19 , Neoplasias , Criança , Humanos , Pandemias , COVID-19/epidemiologia , Atenção à Saúde , Hospitais , Neoplasias/epidemiologia , Neoplasias/terapia
6.
Cancer Med ; 12(14): 15358-15370, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37403745

RESUMO

BACKGROUND: Pediatric Early Warning Systems (PEWS) assist early detection of clinical deterioration in hospitalized children with cancer. Relevant to successful PEWS implementation, the "stages of change" model characterizes stakeholder support for PEWS based on willingness and effort to adopt the new practice. METHODS: At five resource-limited pediatric oncology centers in Latin America, semi-structured interviews were conducted with 71 hospital staff involved in PEWS implementation. Purposive sampling was used to select centers requiring variable time to complete PEWS implementation, with low-barrier centers (3-4 months) and high-barrier centers (10-11 months). Interviews were conducted in Spanish, professionally transcribed, and translated into English. Thematic content analysis explored "stage of change" with constant comparative analysis across stakeholder types and study sites. RESULTS: Participants identified six interventions (training, incentives, participation, evidence, persuasion, and modeling) and two policies (environmental planning and mandates) as effective strategies used by implementation leaders to promote stakeholder progression through stages of change. Key approaches involved presentation of evidence demonstrating PEWS effectiveness, persuasion and incentives addressing specific stakeholder interests, enthusiastic individuals serving as models for others, and policies enforced by hospital directors facilitating habitual PEWS use. Effective engagement targeted hospital directors during early implementation phases to provide programmatic legitimacy for clinical staff. CONCLUSION: This study identifies strategies to promote adoption and maintained use of PEWS, highlighting the importance of tailoring implementation strategies to the motivations of each stakeholder type. These findings can guide efforts to implement PEWS and other evidence-based practices that improve childhood cancer outcomes in resource-limited hospitals.


Assuntos
Deterioração Clínica , Neoplasias , Criança , Humanos , Detecção Precoce de Câncer , Oncologia , Neoplasias/diagnóstico , Neoplasias/terapia , Hospitais
7.
Front Oncol ; 13: 1122355, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37207162

RESUMO

Background: Pediatric Early Warning Systems (PEWS) aid in identification of deterioration in hospitalized children with cancer but are underutilized in resource-limited settings. Proyecto EVAT is a multicenter quality improvement (QI) collaborative in Latin America to implement PEWS. This study investigates the relationship between hospital characteristics and time required for PEWS implementation. Methods: This convergent mixed-methods study included 23 Proyecto EVAT childhood cancer centers; 5 hospitals representing quick and slow implementers were selected for qualitative analysis. Semi-structured interviews were conducted with 71 stakeholders involved in PEWS implementation. Interviews were recorded, transcribed and translated to English, then coded using a priori and novel codes. Thematic content analysis explored the impact of hospital characteristics and QI experience on time required for PEWS implementation and was supplemented by quantitative analysis exploring the relationship between hospital characteristics and implementation time. Results: In both quantitative and qualitative analysis, material and human resources to support PEWS significantly impacted time to implementation. Lack of resources produced various obstacles that extended time necessary for centers to achieve successful implementation. Hospital characteristics, such as funding structure and type, influenced PEWS implementation time by determining their resource-availability. Prior hospital or implementation leader experience with QI, however, helped facilitate implementation by assisting implementers predict and overcome resource-related challenges. Conclusions: Hospital characteristics impact time required to implement PEWS in resource-limited childhood cancer centers; however, prior QI experience helps anticipate and adapt to resource challenges and more quickly implement PEWS. QI training should be a component of strategies to scale-up use of evidence-based interventions like PEWS in resource-limited settings.

8.
JAMA Netw Open ; 5(3): e221547, 2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-35262714

RESUMO

Importance: Pediatric early warning systems (PEWS) aid with early identification of clinical deterioration and improve outcomes in children with cancer hospitalized in resource-limited settings; however, there may be barriers to implementation. Objective: To evaluate stakeholder-reported barriers and enablers to PEWS implementation in resource-limited hospitals. Design, Setting, and Participants: In this qualitative study, semistructured stakeholder interviews were conducted at 5 resource-limited pediatric oncology centers in 4 countries in Latin America. Hospitals participating in a multicenter collaborative to implement PEWS were purposefully sampled based on time required for implementation (fast vs slow), and stakeholders interviewed included physicians, nurses, and administrators, involved in PEWS implementation. An interview guide was developed using the Consolidated Framework for Implementation Research (CFIR). Interviews were conducted virtually in Spanish, audiorecorded, and professionally transcribed and translated into English. A codebook was developed a priori using the CFIR and supplemented with codes inductively derived from transcript review. Two coders independently analyzed all transcripts, achieving a κ of 0.8 to 0.9. The study was conducted from June 1 to August 31, 2020. Main Outcomes and Measures: Thematic analysis was conducted based on CFIR domains (inner setting, characteristics of individuals, outer setting, intervention characteristics, and implementation process) to identify barriers and enablers to PEWS implementation. Results: Seventy-one staff involved in PEWS implementation were interviewed, including 32 physicians (45%), 32 nurses (45%), and 7 administrators (10%). Of these, 50 were women (70%). Components of the 5 CFIR domains were mentioned by participants as barriers and enablers to PEWS implementation at both fast- and slow-implementing centers. Participants emphasized barriers at the level of the clinical staff, hospital, external factors, and PEWS intervention. These barriers included staff resistance to change, inadequate resources, components of health systems, and the perceived origin and complexity of PEWS. At all centers, most barriers were successfully converted to enablers during the implementation process through targeted strategies, such as early stakeholder engagement and adaptation, including adapting PEWS to better fit the local context and changing the hospital setting to support ongoing use of PEWS. Conclusions and Relevance: To date, this is the first multicenter, multinational study describing barriers and enablers to PEWS implementation in resource-limited settings. Findings suggest that many barriers are not immutable and can be converted to enablers during the implementation process. This work can serve as a guide for clinicians looking to implement evidence-based interventions to reduce global disparities in patient outcomes.


Assuntos
Deterioração Clínica , Neoplasias , Criança , Feminino , Hospitalização , Hospitais , Humanos , Masculino , Oncologia
9.
Front Oncol ; 12: 1018224, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36313665

RESUMO

Background: Pediatric Early Warning Systems (PEWS) reduce clinical deterioration, improve interdisciplinary communication, and provide cost savings; however, little is known about how these impacts are achieved or related. This study evaluates the multi-level impacts of PEWS in resource-limited pediatric oncology centers. Methods: We conducted 71 semi-structured interviews including physicians (45%), nurses (45%), and administrators (10%) from 5 resource-limited pediatric oncology centers in 4 Latin American countries. Interviews were conducted in Spanish, transcribed, and translated into English. A code book was developed using a priori and inductively derived codes. Transcripts were independently coded by 2 coders, achieving a kappa of 0.8-0.9. Thematic content analysis explored perceived impacts of PEWS at the level of the patient, clinician, healthcare team, and institution. Results: PEWS improved the quality of attention for patients, reducing morbidity and mortality. Clinicians felt more knowledgeable, confident, and empowered providing patient care, resulting in greater job satisfaction. PEWS affected team dynamics by improving interdisciplinary (ward and intensive care unit) and interprofessional (physicians and nurses) relationships and communication. This ultimately led to institutional culture change with emphasis on patient safety, collaboration with other centers, and receipt of institutional awards. Together, these impacts led to hospital-wide support of ongoing PEWS use. Conclusions: In resource-limited hospitals, PEWS use results in multi-level positive impacts on patients, clinicians, teams, and institutions, creating a feedback loop that further supports ongoing PEWS use. These findings can guide advocacy for PEWS to various stakeholders, improve PEWS effectiveness, and inform assessment of other interventions to improve childhood cancer outcomes.

10.
Front Health Serv ; 2: 1004805, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36925775

RESUMO

Background: Sustainability, or continued use of evidence-based interventions for long-term patient benefit, is the least studied aspect of implementation science. In this study, we evaluate sustainability of a Pediatric Early Warning System (PEWS), an evidence-based intervention to improve early identification of clinical deterioration in hospitalized children, in low-resource settings using the Clinical Capacity for Sustainability Framework (CCS). Methods: We conducted a secondary analysis of a qualitative study to identify barriers and enablers to PEWS implementation. Semi-structured interviews with PEWS implementation leaders and hospital directors at 5 Latin American pediatric oncology centers sustaining PEWS were conducted virtually in Spanish from June to August 2020. Interviews were recorded, professionally transcribed, and translated into English. Exploratory thematic content analysis yielded staff perceptions on PEWS sustainability. Coded segments were analyzed to identify participant perception about the current state and importance of sustaining PEWS, as well as sustainability successes and challenges. Identified sustainability determinants were mapped to the CCS to evaluate its applicability. Results: We interviewed 71 staff including physicians (45%), nurses (45%), and administrators (10%). Participants emphasized the importance of sustaining PEWS for continued patient benefits. Identified sustainability determinants included supportive leadership encouraging ongoing interest in PEWS, beneficial patient outcomes enhancing perceived value of PEWS, integrating PEWS into the routine of patient care, ongoing staff turnover creating training challenges, adequate material resources to promote PEWS use, and the COVID-19 pandemic. While most identified factors mapped to the CCS, COVID-19 emerged as an additional external sustainability challenge. Together, these challenges resulted in multiple impacts on PEWS sustainment, ranging from a small reduction in PEWS quality to complete disruption of PEWS use and subsequent loss of benefits to patients. Participants described several innovative strategies to address identified challenges and promote PEWS sustainability. Conclusion: This study describes clinician perspectives on sustainable implementation of evidence-based interventions in low-resource settings, including sustainability determinants and potential sustainability strategies. Identified factors mapped well to the CCS, however, external factors, such as the COVID pandemic, may additionally impact sustainability. This work highlights an urgent need for theoretically-driven, empirically-informed strategies to support sustainable implementation of evidence-based interventions in settings of all resource-levels.

11.
PLoS One ; 12(12): e0184957, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29211732

RESUMO

During the first postnatal week of mouse development, radial glial cells lining the ventricles of the brain differentiate into ependymal cells, undergoing a morphological change from pseudostratified cuboidal cells to a flattened monolayer. Concomitant with this change, multiple motile cilia are generated and aligned on each nascent ependymal cell. Proper ependymal cell development is crucial to forming the brain tissue:CSF barrier, and to the establishment of ciliary CSF flow, but the mechanisms that regulate this differentiation event are poorly understood. The JhylacZ mouse line carries an insertional mutation in the Jhy gene (formerly 4931429I11Rik), and homozygous JhylacZ/lacZ mice develop a rapidly progressive juvenile hydrocephalus, with defects in ependymal cilia morphology and ultrastructure. Here we show that beyond just defective motile cilia, JhylacZ/lacZ mice display abnormal ependymal cell differentiation. Ventricular ependyma in JhylacZ/lacZ mice retain an unorganized and multi-layered morphology, representative of undifferentiated ependymal (radial glial) cells, and they show altered expression of differentiation markers. Most JhylacZ/lacZ ependymal cells do eventually acquire some differentiated ependymal characteristics, suggesting a delay, rather than a block, in the differentiation process, but ciliogenesis remains perturbed. JhylacZ/lacZ ependymal cells also manifest disruptions in adherens junction formation, with altered N-cadherin localization, and have defects in the polarized organization of the apical motile cilia that do form. Functional studies showed that cilia of JhylacZ/lacZ mice have severely reduced motility, a potential cause for the development of hydrocephalus. This work shows that JHY does not only control ciliogenesis, but is a crucial component of the ependymal differentiation process, with ciliary defects likely a consequence of altered ependymal differentiation.


Assuntos
Diferenciação Celular/genética , Cílios/fisiologia , Epêndima/química , Proteínas de Membrana/genética , Junções Aderentes/metabolismo , Animais , Biomarcadores/metabolismo , Caderinas/metabolismo , Polaridade Celular , Ventrículos Cerebrais/citologia , Ventrículos Cerebrais/metabolismo , Camundongos , Camundongos Transgênicos , Microscopia Eletrônica de Varredura
12.
Mech Dev ; 130(2-3): 143-59, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23059197

RESUMO

Numerous studies have implicated Delta-like 1 (DLK1), a transmembrane protein that shares homology with Notch ligands, in embryonic growth and differentiation. Dlk1 expression is widespread, though not ubiquitous, during early development, but is confined to a few specific cell types in adults. Adult Dlk1-expressing tissues include the Insulin-producing ß-cells of the pancreas and the Growth hormone-producing somatotrophs of the pituitary gland. Previously generated Dlk1 null mice (Dlk1(Sul-pat)), display a partially penetrant neonatal lethality and a complex pattern of developmental and adult phenotypes. Here we describe the generation of a conditional Dlk1 mouse line (Dlk1(flox)) to facilitate cell type-specific deletion of the Dlk1 gene, providing a powerful system to explore each aspect of the Dlk1 null phenotype. Four tissue-specific Cre mouse lines were used to produce individual Dlk1 deletions in pancreatic ß-cells, pituitary somatotrophs and the endothelial cells of the embryo and placenta, key candidates for the Dlk1 phenotype. Contrary to expectations, all of these conditional mice were fully viable, and none recapitulated any aspect of the Dlk1(Sul-pat) null mice. Dlk1 expression is therefore not essential for the normal development of ß-cells, somatotrophs and endothelial cells, and the tissues responsible for the Dlk1 null phenotype remain to be identified. Dlk1(flox) mice will continue to provide an important tool for further research into the function of Dlk1.


Assuntos
Deleção de Genes , Peptídeos e Proteínas de Sinalização Intercelular/genética , Animais , Proteínas de Ligação ao Cálcio , Dieta Hiperlipídica , Desenvolvimento Embrionário/genética , Células Endoteliais/metabolismo , Feminino , Genes Letais , Células Secretoras de Insulina/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Gordura Intra-Abdominal/crescimento & desenvolvimento , Gordura Intra-Abdominal/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Tamanho do Órgão , Especificidade de Órgãos , Pâncreas/citologia , Pâncreas/crescimento & desenvolvimento , Hipófise/citologia , Hipófise/crescimento & desenvolvimento , Placenta/anatomia & histologia , Placenta/metabolismo , Gravidez , Somatotrofos/metabolismo
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