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1.
BMC Health Serv Res ; 24(1): 430, 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38575960

RESUMO

BACKGROUND: NHS England funded 40 Mental Health and Wellbeing Hubs to support health and social care staff affected by the COVID-19 pandemic. We aimed to document variations in how national guidance was adapted to the local contexts of four Hubs in the North of England. METHODS: We used a modified version of Price's (2019) service mapping methodology. Service level data were used to inform the analysis. A mapping template was adapted from a range of tools, including the European Service Mapping Schedule, and reviewed by Hub leads. Key data included service model; staffing; and interventions. Data were collected between March 2021 - March 2022 by site research assistants. Findings were accuracy-checked by Hub leads, and a logic model developed to theorise how the Hubs may effect change. RESULTS: Hub goals and service models closely reflected guidance; offering: proactive outreach; team-based support; clinical assessment; onward referral, and rapid access to mental health support (in-house and external). Implementation reflected a service context of a client group with high mental health need, and high waiting times at external mental health services. Hubs were predominantly staffed by experienced clinicians, to manage these mental health presentations and organisational working. Formulation-based psychological assessment and the provision of direct therapy were not core functions of the NHS England model, however all Hubs incorporated these adaptations into their service models in response to local contexts, such as extensive waiting lists within external services, and/or client presentations falling between gaps in existing service provision. Finally, a standalone clinical records system was seen as important to reassure Hub users of confidentiality. Other more nuanced variation depended on localised contexts. CONCLUSION: This study provides a map for setting up services, emphasising early understandings of how new services will integrate within existing systems. Local and regional contexts led to variation in service configuration. Whilst additional Hub functions are supported by available literature, further research is needed to determine whether these functions should comprise essential components of staff wellbeing services moving forward. Future research should also determine the comparative effectiveness of service components, and the limits of permissible variation. STUDY REGISTRATION: researchregistry6303.


Assuntos
Serviços de Saúde Mental , Resiliência Psicológica , Humanos , Saúde Mental , Pandemias , Apoio Social
2.
BMJ Open ; 13(8): e071826, 2023 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-37612138

RESUMO

OBJECTIVES: Evaluate the implementation of Hubs providing access to psychological support for health and social care keyworkers affected by the COVID-19 pandemic. DESIGN: Qualitative interviews informed by normalisation process theory to understand how the Hub model became embedded into normal practice, and factors that disrupted normalisation of this approach. SETTING: Three Resilience Hubs in the North of England. PARTICIPANTS: Hub staff, keyworkers who accessed Hub support (Hub clients), keyworkers who had not accessed a Hub, and wider stakeholders involved in the provision of staff support within the health and care system (N=63). RESULTS: Hubs were generally seen as an effective way of supporting keyworkers, and Hub clients typically described very positive experiences. Flexibility and adaptability to local needs were strongly valued. Keyworkers accessed support when they understood the offer, valuing a confidential service that was separate from their organisation. Confusion about how Hubs differed from other support prevented some from enrolling. Beliefs about job roles, unsupportive managers, negative workplace cultures and systemic issues prevented keyworkers from valuing mental health support. Lack of support from managers discouraged keyworker engagement with Hubs. Black, Asian and minority ethnic keyworkers impacted by racism felt that the Hubs did not always meet their needs. CONCLUSIONS: Hubs were seen as a valuable, responsive and distinct part of the health and care system. Findings highlight the importance of improving promotion and accessibility of Hubs, and continuation of confidential Hub support. Policy implications for the wider health and care sector include the central importance of genuine promotion of and value placed on mental health support by health and social care management, and the creation of psychologically safe work environments. Diversity and cultural competency training is needed to better reach under-represented communities. Findings are consistent with the international literature, therefore, likely to have applicability outside of the current context.


Assuntos
COVID-19 , Pessoal de Saúde , Pandemias , Sistemas de Apoio Psicossocial , Assistentes Sociais , Humanos , Asiático , Aconselhamento , Apoio Social/psicologia , Pessoal de Saúde/psicologia , Assistentes Sociais/psicologia , População Negra , Grupos Minoritários , Reino Unido , Estresse Ocupacional/etnologia , Estresse Ocupacional/psicologia , Estresse Ocupacional/terapia
3.
Genes Dev ; 37(13-14): 621-639, 2023 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-37541760

RESUMO

Punctuated bursts of structural genomic variations (SVs) have been described in various organisms, but their etiology remains incompletely understood. Homologous recombination (HR) is a template-guided mechanism of repair of DNA double-strand breaks and stalled or collapsed replication forks. We recently identified a DNA break amplification and genome rearrangement pathway originating from the endonucleolytic processing of a multi-invasion (MI) DNA joint molecule formed during HR. Genome-wide approaches confirmed that multi-invasion-induced rearrangement (MIR) frequently leads to several repeat-mediated SVs and aneuploidies. Using molecular and genetic analysis and a novel, highly sensitive proximity ligation-based assay for chromosomal rearrangement quantification, we further delineate two MIR subpathways. MIR1 is a universal pathway occurring in any sequence context, which generates secondary breaks and frequently leads to additional SVs. MIR2 occurs only if recombining donors exhibit substantial homology and results in sequence insertion without additional breaks or SVs. The most detrimental MIR1 pathway occurs late on a subset of persisting DNA joint molecules in a PCNA/Polδ-independent manner, unlike recombinational DNA synthesis. This work provides a refined mechanistic understanding of these HR-based SV formation pathways and shows that complex repeat-mediated SVs can occur without displacement DNA synthesis. Sequence signatures for inferring MIR1 from long-read data are proposed.


Assuntos
Instabilidade Genômica , Rearranjo Gênico , Recombinação Homóloga , Seleção Genética , DNA/genética , DNA/metabolismo , Cromossomos Fúngicos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo
4.
bioRxiv ; 2023 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-36993162

RESUMO

Punctuated bursts of structural genomic variations (SVs) have been described in various organisms, but their etiology remains incompletely understood. Homologous recombination (HR) is a template-guided mechanism of repair of DNA double-strand breaks and stalled or collapsed replication forks. We recently identified a DNA break amplification and genome rearrangement pathway originating from the endonucleolytic processing of a multi-invasion (MI) DNA joint molecule formed during HR. Genome-wide sequencing approaches confirmed that multi-invasion-induced rearrangement (MIR) frequently leads to several repeat-mediated SVs and aneuploidies. Using molecular and genetic analysis, and a novel, highly sensitive proximity ligation-based assay for chromosomal rearrangement quantification, we further delineate two MIR sub-pathways. MIR1 is a universal pathway occurring in any sequence context, which generates secondary breaks and frequently leads to additional SVs. MIR2 occurs only if recombining donors exhibit substantial homology, and results in sequence insertion without additional break or SV. The most detrimental MIR1 pathway occurs late on a subset of persisting DNA joint molecules in a PCNA/Polδ-independent manner, unlike recombinational DNA synthesis. This work provides a refined mechanistic understanding of these HR-based SV formation pathways and shows that complex repeat-mediated SVs can occur without displacement DNA synthesis. Sequence signatures for inferring MIR1 from long-read data are proposed.

5.
Dementia (London) ; 22(1): 85-104, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36345864

RESUMO

BACKGROUND: In the United Kingdom, the use of the terms 'complex' and 'complexity' alongside dementia is reflected in a number of policy and practice documents. However, there is a lack of evidence that explores how complexity is perceived, constructed and experienced by people with dementia, family carers and practitioners working in the NHS dementia inpatient assessment wards [dementia assessment wards]. OBJECTIVE: To explore the meaning and concept of complexity in dementia from within the setting of a dementia assessment ward and develop a practice model. METHODS: The study was conducted over three phases: 1) an online electronic survey of UK national dementia leaders; 2) individual interviews and a focus group with dementia practitioners in two dementia assessment wards; 3) case studies of four patients with dementia resident on a dementia assessment ward which included their identified family carer/consultee, the named clinician on the ward involved in that person's care and a care records review. RESULTS: The findings highlighted that complexity is constructed through a number of interconnected and interrelated domains that vary in acuity. These findings have been developed into the '3 Fs Model of Complexity' and the 3'Fs' stand for Fixed, Flexible and Fluctuating. The Fixed domain consists of six components which are always present in complexity. The Flexible domain consists of 14 components and a person with dementia may experience any number of Flexible domain components at any one time. The Fluctuating domain highlights that all components have the ability to vary in their acuity. CONCLUSION: The '3 Fs Model of Complexity' may facilitate a more holistic view of a person with dementia than when 'symptoms' are viewed in isolation. Going forward, and subject to further refinement and testing, the '3 Fs Model of Complexity' could help guide the selection of tailored, personalised interventions for people with dementia, including formulation approaches.


Assuntos
Demência , Humanos , Saúde Mental , Pacientes Internados , Medicina Estatal , Hospitais , Cuidadores/psicologia
6.
J Cyst Fibros ; 20(5): e46-e52, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33814320

RESUMO

BACKGROUND: Exercise tolerance in people with CF and advanced lung disease is often reduced. While supplemental oxygen can improve oxygenation, it does not affect dyspnoea, fatigue or comfort. Nasal high-flow therapy (NHFT), thanks to its pathophysiological mechanisms, could improve exercise tolerance, saturation and dyspnoea. This study explores the feasibility of conducting a clinical trial of using NHFT in patients with CF during exercise. METHODS: A pilot, open-label, randomized crossover trial was performed, enroling 23 participants with CF and severe lung disease. Participants completed two treadmill walking test (TWT) with and without NHFT at 24-48 h interval. Primary outcome was trial feasibility, and exploratory outcomes were TWT distance (TWTD), SpO2, transcutaneous CO2, dyspnoea and comfort. RESULTS: Recruitment rate was 2.4 subjects/month with 1.3:1 screening-to-randomization ratio. No adverse events caused by NHFT were observed. Tolerability was good and data completion rate was 100%. Twenty subjects (91%) were included in the exploratory study. Mean difference in TWTD on NHFT was 19 m (95% CI [4.8 - 33.1]). SpO2 was similar, but respiratory rate and mean tcCO2 were lower on NHFT (mean difference = -3.9 breaths/min 95% CI [-5.9 - -1.9] and -0.22 kPa 95% CI [-0.4 - 0.04]). NHFT reduced exercise-induced dyspnoea and discomfort. CONCLUSION: Trials using NHFT in patients with CF during exercise are feasible. NHFT appears to improve walking distance, control respiratory rate, CO2, dyspnoea and improve comfort. A larger trial with a longer intervention is feasible and warranted to confirm the impact of NHFT in training programmes for patients with CF.


Assuntos
Fibrose Cística/fisiopatologia , Fibrose Cística/terapia , Terapia por Exercício , Tolerância ao Exercício , Oxigenoterapia , Adulto , Estudos Cross-Over , Estudos de Viabilidade , Feminino , Humanos , Masculino , Projetos Piloto , Teste de Caminhada
7.
Respir Care ; 66(3): 466-474, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32900912

RESUMO

BACKGROUND: Noninvasive ventilation (NIV) is routinely used to treat patients with cystic fibrosis and respiratory failure. However, evidence on its use is limited, with no data on its role in disease progression and outcomes. The aim of this study was to assess the indications of NIV use and to describe the outcomes associated with NIV in adults with cystic fibrosis in a large adult tertiary center. METHODS: A retrospective analysis of data captured prospectively on the unit electronic patient records was performed. All patients with cystic fibrosis who received NIV over a 10-y period were included in the study. A priori, 2 groups were identified based on length of follow-up, with 2 subgroups identified based on duration of NIV treatment. RESULTS: NIV was initiated on 64 occasions. The duration of follow-up was categorized as > 6 months or < 6 months in 31 (48.4%) and 33 (51.6%) occasions, respectively. The most common indications for starting NIV were chronic (48.5%) and acute (32.8%) hypercapnic respiratory failure. Among those with a follow-up > 6 months, subjects who stopped using NIV early showed a steady median (interquartile range) decline in FEV1 (pre-NIV: -0.04 [-0.35 to 0.03] L/y vs post-NIV: -0.07 [-0.35 to 0.01] L/y, P = .51), while among those who continued using it had an improvement in the rate of decline (pre-NIV: -0.25 [-0.52 to -0.02] L/y vs post-NIV: -0.07 [-0.13 to 0.16] L/y, P = .006). No differences in intravenous antibiotic requirement or pulmonary exacerbations were noted with the use of NIV. Pneumothorax and massive hemoptysis occurred independently in 4 cases. CONCLUSIONS: NIV is being used in cystic fibrosis as adjunct therapy for the management of advanced lung disease in a similar fashion to other chronic respiratory conditions. Adherence to NIV treatment can stabilize lung function but does not reduce pulmonary exacerbations or intravenous antibiotic requirement.


Assuntos
Fibrose Cística , Ventilação não Invasiva , Doença Pulmonar Obstrutiva Crônica , Insuficiência Respiratória , Adulto , Fibrose Cística/complicações , Fibrose Cística/terapia , Humanos , Insuficiência Respiratória/etiologia , Insuficiência Respiratória/terapia , Estudos Retrospectivos , Reino Unido
8.
Proc Natl Acad Sci U S A ; 117(45): 28221-28231, 2020 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-33106418

RESUMO

Conventional models of genome evolution are centered around the principle that mutations form independently of each other and build up slowly over time. We characterized the occurrence of bursts of genome-wide loss-of-heterozygosity (LOH) in Saccharomyces cerevisiae, providing support for an additional nonindependent and faster mode of mutation accumulation. We initially characterized a yeast clone isolated for carrying an LOH event at a specific chromosome site, and surprisingly found that it also carried multiple unselected rearrangements elsewhere in its genome. Whole-genome analysis of over 100 additional clones selected for carrying primary LOH tracts revealed that they too contained unselected structural alterations more often than control clones obtained without any selection. We also measured the rates of coincident LOH at two different chromosomes and found that double LOH formed at rates 14- to 150-fold higher than expected if the two underlying single LOH events occurred independently of each other. These results were consistent across different strain backgrounds and in mutants incapable of entering meiosis. Our results indicate that a subset of mitotic cells within a population can experience discrete episodes of systemic genomic instability, when the entire genome becomes vulnerable and multiple chromosomal alterations can form over a narrow time window. They are reminiscent of early reports from the classic yeast genetics literature, as well as recent studies in humans, both in cancer and genomic disorder contexts. The experimental model we describe provides a system to further dissect the fundamental biological processes responsible for punctuated bursts of structural genomic variation.


Assuntos
Genoma Fúngico/genética , Instabilidade Genômica/genética , Saccharomyces cerevisiae/genética , Cromossomos Fúngicos/genética , Perda de Heterozigosidade/genética , Mutação/genética , Recombinação Genética/genética
9.
Genetics ; 216(1): 43-50, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32753390

RESUMO

Remarkably complex patterns of aneuploidy have been observed in the genomes of many eukaryotic cell types, ranging from brewing yeasts to tumor cells. Such aberrant karyotypes are generally thought to take shape progressively over many generations, but evidence also suggests that genomes may undergo faster modes of evolution. Here, we used diploid Saccharomyces cerevisiae cells to investigate the dynamics with which aneuploidies arise. We found that cells selected for the loss of a single chromosome often acquired additional unselected aneuploidies concomitantly. The degrees to which these genomes were altered fell along a spectrum, ranging from simple events affecting just a single chromosome, to systemic events involving many. The striking complexity of karyotypes arising from systemic events, combined with the high frequency at which we detected them, demonstrates that cells can rapidly achieve highly altered genomic configurations during temporally restricted episodes of genomic instability.


Assuntos
Aneuploidia , Genoma Fúngico , Instabilidade Genômica , Cromossomos Fúngicos/genética , Evolução Molecular , Cariótipo , Saccharomyces cerevisiae
10.
Sci Total Environ ; 715: 136944, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32014773

RESUMO

Produced water is the largest waste stream associated with oil and gas operations. This complex fluid contains petroleum hydrocarbons, heavy metals, salts, naturally occurring radioactive materials and any remaining chemical additives. In the United States, west of the 98th meridian, the federal National Pollutant Discharge Elimination System (NPDES) exemption allows release of produced water for agricultural beneficial reuse. The goal of this study was to quantify mutagenicity of a produced water NPDES release and discharge stream. We used four mutation assays in budding yeast cells that provide rate estimates for copy number variation (CNV) duplications and deletions, as well as forward and reversion point mutations. Higher mutation rates were observed at the discharge and decreased with distance downstream, which correlated with the concentrations of known carcinogens detected in the stream (e.g., benzene, radium), described in a companion study. Mutation rate increases were most prominent for CNV duplications and were higher than mutations observed in mixtures of known toxic compounds. Additionally, the samples were evaluated for acute toxicity in Daphnia magna and developmental toxicity in zebrafish. Acute toxicity was minimal, and no developmental toxicity was observed. This study illustrates that chemical analysis alone (McLaughlin et al., 2020) is insufficient for characterizing the risk of produced water NPDES releases and that a thorough evaluation of chronic toxicity is necessary to fully assess produced water for beneficial reuse.


Assuntos
Água/química , Animais , Variações do Número de Cópias de DNA , Daphnia , Gases , Mutagênicos , Óleos , Estados Unidos , Poluentes Químicos da Água
11.
Front Genet ; 10: 782, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31572430

RESUMO

Abundant genomic heterozygosity can be found in wild strains of the budding yeast Saccharomyces cerevisiae isolated from industrial and clinical environments. The extent to which heterozygosity influences the phenotypes of these isolates is not fully understood. One such case is the PE-2/JAY270 strain, a natural hybrid widely adopted by sugarcane bioethanol distilleries for its ability to thrive under harsh biotic and abiotic stresses during industrial scale fermentation, however, it is not known whether or how the heterozygous configuration of the JAY270 genome contributes to its many desirable traits. In this study, we took a step toward exploring this question by conducting an initial functional characterization of JAY270's heteroalleles. We manipulated the abundance and distribution of heterozygous alleles through inbreeding and targeted uniparental disomy (UPD). Unique combinations of homozygous alleles in each inbred strain revealed wide phenotypic variation for at least two important industrial traits: Heat stress tolerance and competitive growth. Quantitative trait loci analyses allowed the identification of broad genomic regions where genetic polymorphisms potentially impacted these traits, and there was no overlap between the loci associated with each. In addition, we adapted an approach to induce bidirectional UPD of three targeted pairs of chromosomes (IV, XIV, and XV), while heterozygosity was maintained elsewhere in the genome. In most cases UPD led to detectable phenotypic alterations, often in opposite directions between the two homozygous haplotypes in each UPD pair. Our results showed that both widespread and regional homozygosity could uncover cryptic phenotypic variation supported by the heteroalleles residing in the JAY270 genome. Interestingly, we characterized multiple examples of inbred and UPD strains that displayed heat tolerance or competitive growth phenotypes that were superior to their heterozygous parent. However, we propose that homozygosity for those regions may be associated with a decrease in overall fitness in the complex and dynamic distillery environment, and that may have contributed to slowing down the erosion of heterozygosity from the JAY270 genome. This study also laid a foundation for approaches that can be expanded to the identification of specific alleles of interest for industrial applications in this and other hybrid yeast strains.

12.
Methods Mol Biol ; 1569: 113-126, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28265992

RESUMO

Cytokinins have been shown to regulate plant immunity. Application of high levels of cytokinin to plants leads to decreased susceptibility to pathogens. In this chapter, we describe a fast and accurate protocol for assessment of cytokinin-induced immunity in Arabidopsis plants against an oomycete plant pathogen.


Assuntos
Arabidopsis/microbiologia , Arabidopsis/fisiologia , Citocininas/metabolismo , Interações Hospedeiro-Patógeno/imunologia , Oomicetos/imunologia , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Imunidade Vegetal , Contagem de Colônia Microbiana , Oomicetos/isolamento & purificação , Esporos Fúngicos
13.
PLoS One ; 11(6): e0156673, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27248141

RESUMO

Sucrose-specific regulation of gene expression is recognized as an important signaling response, distinct from glucose, which serves to modulate plant growth, metabolism, and physiology. The Arabidopsis MYB transcription factor Production of Anthocyanin Pigment-1 (PAP1) plays a key role in anthocyanin biosynthesis and expression of PAP1 is known to be regulated by sucrose. Sucrose treatment of Arabidopsis seedlings led to a 20-fold induction of PAP1 transcript, which represented a 6-fold increase over levels in glucose-treated seedlings. The PAP1 promoter was not sufficient for conferring a sucrose response to a reporter gene and did not correctly report expression of PAP1 in plants. Although we identified 3 putative sucrose response elements in the PAP1 gene, none were found to be necessary for this response. Using deletion analysis, we identified a 90 bp sequence within intron 1 of PAP1 that is necessary for the sucrose response. This sequence was sufficient for conferring a sucrose response to a minimal promoter: luciferase reporter when present in multiple copies upstream of the promoter. This work lays the foundation for dissecting the sucrose signaling pathway of PAP1 and contributes to understanding the interplay between sucrose signaling, anthocyanin biosynthesis, and stress responses.


Assuntos
Antocianinas/biossíntese , Proteínas de Arabidopsis/genética , Arabidopsis/metabolismo , Íntrons , Sacarose/metabolismo , Fatores de Transcrição/genética , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Proteínas Associadas a Pancreatite
14.
J Neurosci ; 26(20): 5393-401, 2006 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-16707791

RESUMO

Patterning of the mouse somatosensory cortex is unusually evident because of the presence of a "barrel field." Presynaptic serotonin and postsynaptic glutamate receptors regulate barrel formation, but little is known of the intracellular signaling pathways through which they act. To determine whether protein kinase A (PKA) plays a role in the development of the barrel field, we examined five viable PKA subunit-specific knock-out (KO) mouse lines for barrel field abnormalities. Barrels are present in these mice, but those lacking the RIIbeta subunit display significantly reduced contrast between the cell densities of barrel hollows and sides compared with wild-type animals. Thalamocortical afferent segregation in the posterior medial barrel subfield appeared normal, suggesting a postsynaptic site of gene action for the RIIbeta protein. Immunoelectron microscopy confirmed that RIIbeta was selectively localized to dendrites and dendritic spines. Mice lacking RIIbeta show reduced glutamate receptor A (GluRA) subunit insertion into the postsynaptic density in postnatal day 7 somatosensory cortex; however, GluRA KO mice developed normal barrels. Our results clearly demonstrate a role for postsynaptic PKA signaling pathways in barrel differentiation. They also demonstrate a clear dissociation between the regulation of GluRA trafficking by PKA and its role in barrel formation. Finally, although a role for PKA downstream of cAMP cannot be ruled out, these data suggest that PKA may not be the principle downstream target because none of the mutants showed a barrelless phenotype similar to that observed in adenylate cyclase type 1 KO mice. These results give insight into activity-dependent mechanisms that regulate barrel formation.


Assuntos
Padronização Corporal/genética , Diferenciação Celular/genética , Proteínas Quinases Dependentes de AMP Cíclico/genética , Malformações do Sistema Nervoso/enzimologia , Malformações do Sistema Nervoso/genética , Córtex Somatossensorial/anormalidades , Córtex Somatossensorial/enzimologia , Animais , Animais Recém-Nascidos , AMP Cíclico/metabolismo , Espinhas Dendríticas/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/genética , Camundongos , Camundongos Knockout , Vias Neurais/anormalidades , Vias Neurais/enzimologia , Subunidades Proteicas/genética , Receptores de N-Metil-D-Aspartato/metabolismo , Membranas Sinápticas/genética , Membranas Sinápticas/metabolismo , Transmissão Sináptica/genética , Núcleos Ventrais do Tálamo/anormalidades , Núcleos Ventrais do Tálamo/enzimologia
15.
J Neurosci ; 26(5): 1355-65, 2006 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-16452659

RESUMO

The development of ordered connections or "maps" within the nervous system is a common feature of sensory systems and is crucial for their normal function. NMDA receptors are known to play a key role in the formation of these maps; however, the intracellular signaling pathways that mediate the effects of glutamate are poorly understood. Here, we demonstrate that SynGAP, a synaptic Ras GTPase activating protein, is essential for the anatomical development of whisker-related patterns in the developing somatosensory pathways in rodent forebrain. Mice lacking SynGAP show only partial segregation of barreloids in the thalamus, and thalamocortical axons segregate into rows but do not form whisker-related patches. In cortex, layer 4 cells do not aggregate to form barrels. In Syngap(+/-) animals, barreloids develop normally, and thalamocortical afferents segregate in layer 4, but cell segregation is retarded. SynGAP is not necessary for the development of whisker-related patterns in the brainstem. Immunoelectron microscopy for SynGAP from layer 4 revealed a postsynaptic localization with labeling in developing postsynaptic densities (PSDs). Biochemically, SynGAP associates with the PSD in a PSD-95-independent manner, and Psd-95(-/-) animals develop normal barrels. These data demonstrate an essential role for SynGAP signaling in the activity-dependent development of whisker-related maps selectively in forebrain structures indicating that the intracellular pathways by which NMDA receptor activation mediates map formation differ between brain regions and developmental stage.


Assuntos
Padronização Corporal , Córtex Somatossensorial/citologia , Córtex Somatossensorial/crescimento & desenvolvimento , Núcleos do Trigêmeo/citologia , Núcleos do Trigêmeo/crescimento & desenvolvimento , Proteínas Ativadoras de ras GTPase/fisiologia , Animais , Proteína 4 Homóloga a Disks-Large , Guanilato Quinases , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Knockout , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Córtex Somatossensorial/enzimologia , Tálamo/citologia , Tálamo/enzimologia , Tálamo/crescimento & desenvolvimento , Núcleos do Trigêmeo/enzimologia , Proteínas Ativadoras de ras GTPase/genética , Proteínas Ativadoras de ras GTPase/metabolismo
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