Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 123
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
2.
Genes Dev ; 31(20): 2085-2098, 2017 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-29138277

RESUMO

Expression of the transcription factors OCT4, SOX2, KLF4, and cMYC (OSKM) reprograms somatic cells into induced pluripotent stem cells (iPSCs). Reprogramming is a slow and inefficient process, suggesting the presence of safeguarding mechanisms that counteract cell fate conversion. One such mechanism is senescence. To identify modulators of reprogramming-induced senescence, we performed a genome-wide shRNA screen in primary human fibroblasts expressing OSKM. In the screen, we identified novel mediators of OSKM-induced senescence and validated previously implicated genes such as CDKN1A We developed an innovative approach that integrates single-cell RNA sequencing (scRNA-seq) with the shRNA screen to investigate the mechanism of action of the identified candidates. Our data unveiled regulation of senescence as a novel way by which mechanistic target of rapamycin (mTOR) influences reprogramming. On one hand, mTOR inhibition blunts the induction of cyclin-dependent kinase (CDK) inhibitors (CDKIs), including p16INK4a, p21CIP1, and p15INK4b, preventing OSKM-induced senescence. On the other hand, inhibition of mTOR blunts the senescence-associated secretory phenotype (SASP), which itself favors reprogramming. These contrasting actions contribute to explain the complex effect that mTOR has on reprogramming. Overall, our study highlights the advantage of combining functional screens with scRNA-seq to accelerate the discovery of pathways controlling complex phenotypes.


Assuntos
Reprogramação Celular , Senescência Celular , Perfilação da Expressão Gênica , RNA Interferente Pequeno , Análise de Sequência de RNA , Serina-Treonina Quinases TOR/fisiologia , Fatores de Transcrição/metabolismo , Animais , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Fibroblastos/citologia , Fibroblastos/metabolismo , Humanos , Fator 4 Semelhante a Kruppel , Camundongos , Análise de Célula Única , Serina-Treonina Quinases TOR/antagonistas & inibidores
3.
Genes Dev ; 30(19): 2187-2198, 2016 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-27737960

RESUMO

Oncogene-induced senescence (OIS) is a potent tumor suppressor mechanism. To identify senescence regulators relevant to cancer, we screened an shRNA library targeting genes deleted in hepatocellular carcinoma (HCC). Here, we describe how knockdown of the SWI/SNF component ARID1B prevents OIS and cooperates with RAS to induce liver tumors. ARID1B controls p16INK4a and p21CIP1a transcription but also regulates DNA damage, oxidative stress, and p53 induction, suggesting that SWI/SNF uses additional mechanisms to regulate senescence. To systematically identify SWI/SNF targets regulating senescence, we carried out a focused shRNA screen. We discovered several new senescence regulators, including ENTPD7, an enzyme that hydrolyses nucleotides. ENTPD7 affects oxidative stress, DNA damage, and senescence. Importantly, expression of ENTPD7 or inhibition of nucleotide synthesis in ARID1B-depleted cells results in re-establishment of senescence. Our results identify novel mechanisms by which epigenetic regulators can affect tumor progression and suggest that prosenescence therapies could be employed against SWI/SNF-mutated cancers.


Assuntos
Carcinoma Hepatocelular/genética , Senescência Celular/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Regulação Neoplásica da Expressão Gênica/genética , Neoplasias Hepáticas/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Animais , Apirase/metabolismo , Carcinoma Hepatocelular/enzimologia , Linhagem Celular , Linhagem Celular Tumoral , Epigênese Genética/genética , Feminino , Humanos , Neoplasias Hepáticas/enzimologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mutação , RNA Interferente Pequeno/genética
5.
Eur Heart J ; 43(36): 3387-3398, 2022 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-35484821

RESUMO

AIMS: To systematically assess late outcomes of acute pulmonary embolism (PE) and to investigate the clinical implications of post-PE impairment (PPEI) fulfilling prospectively defined criteria. METHODS AND RESULTS: A prospective multicentre observational cohort study was conducted in 17 large-volume centres across Germany. Adult consecutive patients with confirmed acute symptomatic PE were followed with a standardized assessment plan and pre-defined visits at 3, 12, and 24 months. The co-primary outcomes were (i) diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH), and (ii) PPEI, a combination of persistent or worsening clinical, functional, biochemical, and imaging parameters during follow-up. A total of 1017 patients (45% women, median age 64 years) were included in the primary analysis. They were followed for a median duration of 732 days after PE diagnosis. The CTEPH was diagnosed in 16 (1.6%) patients, after a median of 129 days; the estimated 2-year cumulative incidence was 2.3% (1.2-4.4%). Overall, 880 patients were evaluable for PPEI; the 2-year cumulative incidence was 16.0% (95% confidence interval 12.8-20.8%). The PPEI helped to identify 15 of the 16 patients diagnosed with CTEPH during follow-up (hazard ratio for CTEPH vs. no CTEPH 393; 95% confidence interval 73-2119). Patients with PPEI had a higher risk of re-hospitalization and death as well as worse quality of life compared with those without PPEI. CONCLUSION: In this prospective study, the cumulative 2-year incidence of CTEPH was 2.3%, but PPEI diagnosed by standardized criteria was frequent. Our findings support systematic follow-up of patients after acute PE and may help to optimize guideline recommendations and algorithms for post-PE care.


Assuntos
Hipertensão Pulmonar , Embolia Pulmonar , Doença Aguda , Adulto , Doença Crônica , Feminino , Humanos , Hipertensão Pulmonar/complicações , Hipertensão Pulmonar/epidemiologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Embolia Pulmonar/complicações , Embolia Pulmonar/diagnóstico , Embolia Pulmonar/epidemiologia , Qualidade de Vida , Fatores de Risco
6.
Am Heart J ; 251: 43-53, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35588898

RESUMO

BACKGROUND: Due to the bleeding risk of full-dose systemic thrombolysis and the lack of major trials focusing on the clinical benefits of catheter-directed treatment, heparin antiocoagulation remains the standard of care for patients with intermediate-high-risk pulmonary embolism (PE). METHODS AND RESULTS: The Higher-Risk Pulmonary Embolism Thrombolysis (HI-PEITHO) study (ClinicalTrials.gov Identifier: NCT04790370) is a multinational multicenter randomized controlled parallel-group comparison trial. Patients with: (1) confirmed acute PE; (2) evidence of right ventricular (RV) dysfunction on imaging; (3) a positive cardiac troponin test; and (4) clinical criteria indicating an elevated risk of early death or imminent hemodynamic collapse, will be randomized 1:1 to treatment with a standardized protocol of ultrasound-facilitated catheter-directed thrombolysis plus anticoagulation, vs anticoagulation alone. The primary outcome is a composite of PE-related mortality, cardiorespiratory decompensation or collapse, or non-fatal symptomatic and objectively confirmed PE recurrence, within 7 days of randomization. Further assessments cover, apart from bleeding complications, a broad spectrum of functional and patient-reported outcomes including quality of life indicators, functional status and the utilization of health care resources over a 12-month follow-up period. The trial plans to include 406 patients, but the adaptive design permits a sample size increase depending on the results of the predefined interim analysis. As of May 11, 2022, 27 subjects have been enrolled. The trial is funded by Boston Scientific Corporation and through collaborative research agreements with University of Mainz and The PERT Consortium. CONCLUSIONS: Regardless of the outcome, HI-PEITHO will establish the first-line treatment in intermediate-high risk PE patients with imminent hemodynamic collapse. The trial is expected to inform international guidelines and set the standard for evaluation of catheter-directed reperfusion options in the future.


Assuntos
Embolia Pulmonar , Disfunção Ventricular Direita , Doença Aguda , Anticoagulantes/uso terapêutico , Catéteres , Fibrinolíticos/uso terapêutico , Humanos , Embolia Pulmonar/diagnóstico por imagem , Embolia Pulmonar/tratamento farmacológico , Qualidade de Vida , Terapia Trombolítica/métodos , Resultado do Tratamento , Disfunção Ventricular Direita/complicações
7.
Blood ; 135(5): 360-370, 2020 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-31774495

RESUMO

The oncogenic events involved in breast implant-associated anaplastic large cell lymphoma (BI-ALCL) remain elusive. To clarify this point, we have characterized the genomic landscape of 34 BI-ALCLs (15 tumor and 19 in situ subtypes) collected from 54 BI-ALCL patients diagnosed through the French Lymphopath network. Whole-exome sequencing (n = 22, with paired tumor/germline DNA) and/or targeted deep sequencing (n = 24) showed recurrent mutations of epigenetic modifiers in 74% of cases, involving notably KMT2C (26%), KMT2D (9%), CHD2 (15%), and CREBBP (15%). KMT2D and KMT2C mutations correlated with a loss of H3K4 mono- and trimethylation by immunohistochemistry. Twenty cases (59%) showed mutations in ≥1 member of the JAK/STAT pathway, including STAT3 (38%), JAK1 (18%), and STAT5B (3%), and in negative regulators, including SOCS3 (6%), SOCS1 (3%), and PTPN1 (3%). These mutations were more frequent in tumor-type samples than in situ samples (P = .038). All BI-ALCLs expressed pSTAT3, regardless of the mutational status of genes in the JAK/STAT pathway. Mutations in the EOMES gene (12%) involved in lymphocyte development, PI3K-AKT/mTOR (6%), and loss-of-function mutations in TP53 (12%) were also identified. Copy-number aberration (CNA) analysis identified recurrent alterations, including gains on chromosomes 2, 9p, 12p, and 21 and losses on 4q, 8p, 15, 16, and 20. Regions of CNA encompassed genes involved in the JAK/STAT pathway and epigenetic regulators. Our results show that the BI-ALCL genomic landscape is characterized by not only JAK/STAT activating mutations but also loss-of-function alterations of epigenetic modifiers.


Assuntos
Implantes de Mama/efeitos adversos , Epigênese Genética , Janus Quinases/metabolismo , Linfoma Anaplásico de Células Grandes/etiologia , Linfoma Anaplásico de Células Grandes/genética , Fatores de Transcrição STAT/metabolismo , Transdução de Sinais , Adulto , Idoso , Idoso de 80 Anos ou mais , Variações do Número de Cópias de DNA , Feminino , Genoma Humano , Humanos , Linfoma Anaplásico de Células Grandes/patologia , Pessoa de Meia-Idade , Mutação/genética
8.
Br J Dermatol ; 187(6): 970-980, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35895386

RESUMO

BACKGROUND: Primary cutaneous peripheral T-cell lymphomas with a T-follicular helper phenotype (pcTFH-PTCL) are poorly characterized, and often compared to, but not corresponding with, mycosis fungoides (MF), Sézary syndrome, primary cutaneous CD4+ lymphoproliferative disorder, and skin manifestations of angioimmunoblastic T-cell lymphomas (AITL). OBJECTIVES: We describe the clinicopathological features of pcTFH-PTCL in this original series of 23 patients, and also characterize these cases molecularly. METHODS: Clinical and histopathological data of the selected patients were reviewed. Patient biopsy samples were also analysed by targeted next-generation sequencing. RESULTS: All patients (15 men, eight women; median age 66 years) presented with skin lesions, without systemic disease. Most were stage T3b, with nodular (n = 16), papular (n = 6) or plaque (atypical for MF, n = 1) lesions. Three (13%) developed systemic disease and died of lymphoma. Nine (39%) patients received more than one line of chemotherapy. Histologically, the lymphomas were CD4+ T-cell proliferations, usually dense and located in the deep dermis (n = 14, 61%), with the expression of at least two TFH markers (CD10, CXCL13, PD1, ICOS, BCL6), including three markers in 16 cases (70%). They were associated with a variable proportion of B cells. Eight patients were diagnosed with an associated B-cell lymphoproliferative disorder (LPD) on biopsy, including Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma (n = 3), EBV+ LPD (n = 1) and monotypic plasma cell LPD (n = 4). Targeted sequencing showed four patients to have a mutated TET2-RHOAG17V association (as frequently seen in AITL) and another a TET2/DNMT3A/PLCG1/SETD2 mutational profile. The latter patient, one with a TET2-RHOA association, and one with no detected mutations, developed systemic disease and died. Five other patients showed isolated mutations in TET2 (n = 1), PLCG1 (n = 2), SETD2 (n = 1) or STAT5B (n = 1). CONCLUSIONS: Patients with pcTFH-PTCL have pathological and genetic features that overlap with those of systemic lymphoma of TFH derivation. Clinically, most remained confined to the skin, with only three patients showing systemic spread and death. Whether pcTFH-PTCL should be integrated as a new subgroup of TFH lymphomas in future classifications is still a matter of debate. What is already known about this topic? There is a group of cutaneous lymphomas that express T-follicular helper (TFH) markers that do not appear to correspond to existing World Health Organization diagnostic entities. These include mycosis fungoides, Sézary syndrome, or primary cutaneous CD4+ small/medium-sized T-cell lymphoproliferative disorder or cutaneous extensions of systemic peripheral T-cell lymphomas (PTCL) with TFH phenotype. What does this study add? This is the first large original series of patients with a diagnosis of primary cutaneous PTCL with a TFH phenotype (pcTFH-PTCL) to be molecularly characterized. pcTFH-PTCL may be a standalone group of cutaneous lymphomas with clinicopathological and molecular characteristics that overlap with those of systemic TFH lymphomas, such as angioimmunoblastic T-cell lymphoma, and does not belong to known diagnostic groups of cutaneous lymphoma. This has an impact on the treatment and follow-up of patients; the clinical behaviour needs to be better clarified in further studies to tailor patient management.


Assuntos
Infecções por Vírus Epstein-Barr , Linfadenopatia Imunoblástica , Linfoma de Células B , Linfoma Cutâneo de Células T , Linfoma de Células T Periférico , Micose Fungoide , Síndrome de Sézary , Neoplasias Cutâneas , Feminino , Humanos , Linfoma de Células T Periférico/genética , Linfoma de Células T Periférico/diagnóstico , Linfoma de Células T Periférico/patologia , Síndrome de Sézary/genética , Síndrome de Sézary/patologia , Infecções por Vírus Epstein-Barr/metabolismo , Infecções por Vírus Epstein-Barr/patologia , Linfócitos T Auxiliares-Indutores/metabolismo , Herpesvirus Humano 4 , Fenótipo , Micose Fungoide/diagnóstico , Micose Fungoide/genética , Neoplasias Cutâneas/patologia , Linfoma de Células B/patologia , Linfoma Cutâneo de Células T/genética , Linfoma Cutâneo de Células T/patologia
9.
Arch Phys Med Rehabil ; 103(3): 590-598, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34822844

RESUMO

The Rehabilitation Treatment Specification System (RTSS) provides a framework to identify specific components of treatments developed within various rehabilitation disciplines (eg, physical, occupational, or speech-language therapy). Furthermore, this framework offers the opportunity to identify the target and active ingredients of a therapy approach as well as the mechanism of action by which it is hypothesized to effect change in abilities or functions. In this article, we apply the RTSS framework to the characterization of a sample of treatments for aphasia that are based on cognitive-linguistic models of language processing. Our discussion of these applications centers on the benefits of this classification system and additional criteria to consider when evaluating cognitive-linguistic treatments for aphasia.


Assuntos
Afasia , Afasia/reabilitação , Cognição , Humanos , Idioma , Linguística , Fonoterapia
10.
Arch Phys Med Rehabil ; 103(3): 574-580, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34748758

RESUMO

A considerable body of research supports the use of behavioral communication treatment as the standard of care for aphasia. In spite of robust progress in clinical aphasiology, many questions regarding optimal care remain unanswered. One of the major challenges to progress in the field is the lack of a common framework to adequately describe individual treatments, which, if available, would allow comparisons across studies as well as improved communication among researchers, clinicians, and other stakeholders. Here, we describe how aphasia treatment approaches can be systematically characterized using the Rehabilitation Treatment Specification System (RTSS). At the core of the RTSS is a tripartite structure that focuses on targets (the behavior that is expected to change as a result of treatment), ingredients (what a clinician does to affect change in the target), and mechanism(s) of action (why a given treatment works by linking the ingredients to the target). Three separate articles in the current issue specifically describe how the RTSS can be used to describe different kinds of aphasia treatment approaches: functional approaches, cognitive-linguistic approaches, and biological approaches. It is our hope that the application of the RTSS in clinical aphasiology will improve communication in published studies, grant proposals, and in the clinical care of persons with aphasia.


Assuntos
Afasia , Terapia Cognitivo-Comportamental , Afasia/reabilitação , Comunicação , Humanos
11.
Ann Diagn Pathol ; 60: 151997, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35777330

RESUMO

Neurofibromatosis type 1 (NF1) is a common autosomal dominant disorder. The role of angiogenesis and VEGF pathway in the pathogenesis of neurofibromas and malignant peripheral nerve sheath tumors (MPNSTs) remains poorly understood. We assessed the expression of VEGF and VEGFR family members in cohorts of plexiform neurofibromas (pNF), MPNSTs and MPNST cell lines at transcript [pNF, n = 49; MPNST, n = 34] and protein levels [pNF, n = 21; MPNST, n = 9]. VEGF and VEGFR members were variably expressed in cell lines. VEGFA (p = 3.10-5), VEGFR1 (p = 0.08), and VEGFR2 (p = 2.10-4) mRNAs were overexpressed in MPNSTs in comparison with pNFs. Both VEGFA and VEGFR1 proteins were expressed by spindle tumor cells of pNFs and MPNSTs. VEGFA was expressed more in MPNSTs than in pNFs (p = 9.10-6) and a trend for VEGFR1 overexpression was observed (p = 0.06). VEGFR2 was not found at the protein level. The microvascular density was significantly reduced in MPNSTs as compared to pNFs (p = 0.0025), with no differences regarding the expression of the activated phosphorylated forms of ERK (P-ERK [p = 0.63]) and AKT (P-AKT [p = 0.41]) in endothelial cells, suggesting that VEGF-dependant angiogenesis may not be critical for MPNST oncogenesis. Altogether, these results indicate that the VEGF-VEGFR pathway may play a role in the development of pNFs and MPNSTs, independently of angiogenesis. Whether or not it drives an oncogenic autocrine/paracrine loop in neoplastic cells, participating in an increased activation of signaling pathways downstream of tyrosine kinase receptors, including VEGFRs, is a tempting hypothesis. Nevertheless, the specific targeting of angiogenesis in MPNSTs may not be sufficient to slow down tumor growth.


Assuntos
Neoplasias de Bainha Neural , Neurofibromatose 1 , Neurofibrossarcoma , Humanos , Carcinogênese , Células Endoteliais/metabolismo , Neovascularização Patológica , Neoplasias de Bainha Neural/patologia , Neurofibromatose 1/patologia , Proteínas Proto-Oncogênicas c-akt , Receptores de Fatores de Crescimento do Endotélio Vascular , Fator A de Crescimento do Endotélio Vascular/metabolismo , Comunicação Autócrina
12.
J Gambl Stud ; 38(3): 1075-1092, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34286413

RESUMO

Consequences experienced by the partners of individuals with a gambling disorder are well documented. However, little is known about the deleterious effects experienced by other people than partners of gamblers. A better understanding of these consequences could help improve clinical practices. The goal of this paper is to compare the consequences experienced by partners of gamblers with those experienced by their close family members (parents, adult children, siblings) by using the categorization method proposed by Langham et al. (BMC Public Health, 2016). To achieve this goal, 46 semi-structured interviews were conducted. Results indicate that the extent and intensity of the consequences experienced vary widely based on their level of emotional and financial involvement with the gambler. Considering the specific elements involved for each type of person in a gambler's life, future research should distinguish participants based on the nature of their relationship with the gambler.


Assuntos
Jogo de Azar , Adulto , Humanos , Família/psicologia , Jogo de Azar/psicologia , Motivação , Filhos Adultos
13.
Int J Mol Sci ; 23(16)2022 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-36012633

RESUMO

In response to many stresses, such as oncogene activation or DNA damage, cells can enter cellular senescence, a state of proliferation arrest accompanied by a senescence-associated secretory phenotype (SASP). Cellular senescence plays a key role in many physiopathological contexts, including cancer, aging and aging-associated diseases, therefore, it is critical to understand how senescence is regulated. Calcium ions (Ca2+) recently emerged as pivotal regulators of cellular senescence. However, how Ca2+ levels are controlled during this process is barely known. Here, we report that intracellular Ca2+ contents increase in response to many senescence inducers in immortalized human mammary epithelial cells (HMECs) and that expression of calbindin 1 (CALB1), a Ca2+-binding protein, is upregulated in this context, through the Ca2+-dependent calcineurin/NFAT pathway. We further show that overexpression of CALB1 buffers the rise in intracellular Ca2+ levels observed in senescent cells. Finally, we suggest that increased expression of Ca2+-binding proteins calbindins is a frequent mark of senescent cells. This work thus supports that, together with Ca2+channels, Ca2+-binding proteins modulate Ca2+ levels and flux during cellular senescence. This opens potential avenues of research to better understand the role of Ca2+ and of Ca2+-binding proteins in regulating cellular senescence.


Assuntos
Envelhecimento , Calbindina 1 , Cálcio , Senescência Celular , Calbindina 1/metabolismo , Cálcio/metabolismo , Dano ao DNA , Células Epiteliais/metabolismo , Humanos
14.
Nucleic Acids Res ; 47(7): 3407-3421, 2019 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-30753595

RESUMO

The proper tissue-specific regulation of gene expression is essential for development and homeostasis in metazoans. However, the illegitimate expression of normally tissue-restricted genes-like testis- or placenta-specific genes-is frequently observed in tumors; this promotes transformation, but also allows immunotherapy. Two important questions are: how is the expression of these genes controlled in healthy cells? And how is this altered in cancer? To address these questions, we used an unbiased approach to test the ability of 350 distinct genetic or epigenetic perturbations to induce the illegitimate expression of over 40 tissue-restricted genes in primary human cells. We find that almost all of these genes are remarkably resistant to reactivation by a single alteration in signaling pathways or chromatin regulation. However, a few genes differ and are more readily activated; one is the placenta-expressed gene ADAM12, which promotes invasion. Using cellular systems, an animal model, and bioinformatics, we find that a non-canonical but druggable TGF-ß/KAT2A/TAK1 axis controls ADAM12 induction in normal and cancer cells. More broadly, our data show that illegitimate gene expression in cancer is an heterogeneous phenomenon, with a few genes activatable by simple events, and most genes likely requiring a combination of events to become reactivated.


Assuntos
Regulação da Expressão Gênica/genética , Neoplasias/genética , Especificidade de Órgãos/genética , Transcrição Gênica/genética , Proteína ADAM12/genética , Proteína ADAM12/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Cromatina/genética , Cromatina/metabolismo , Regulação Neoplásica da Expressão Gênica/genética , Histona Acetiltransferases/metabolismo , Humanos , Neoplasias/metabolismo , Neoplasias/patologia , Proteínas Serina-Treonina Quinases/metabolismo , Interferência de RNA , Transdução de Sinais/genética , Fator de Crescimento Transformador beta1/metabolismo , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/metabolismo
15.
Neuropsychol Rehabil ; 31(5): 731-772, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32114906

RESUMO

Recent approaches to interventions for aphasia have incorporated verbal short-term memory (STM) and working memory (WM) components. We investigated whether a treatment involving repetition of word sequences after a response delay would improve tolerance of increased verbal STM load in repetition and, consequently, improve performance on repetition and other language tasks. Eight individuals with aphasia participated. We used a single subject design with outcome measures on near-transfer tasks closely related to the treatment task and far-transfer tasks more distantly related to the treatment task. We minimized repeated presentation of stimuli in all phases of treatment to control for confounding effects of repeated exposure of treated items. Four participants demonstrated modest acquisition effects. On outcome measures, we observed improvements by some participants on near-transfer tasks, (repetition of concrete and abstract word strings and verbal spans) and far-transfer tasks (naming and discourse). Some participants demonstrated a significant decline in word repetition accuracy after a response delay before treatment, indicating difficulty in maintaining activation of linguistic representations. It was these participants who showed the most improvement on outcome measures. More studies are needed to determine who will respond to this treatment and what factors might influence the effectiveness of this treatment approach.


Assuntos
Afasia , Memória de Curto Prazo , Afasia/etiologia , Cognição , Humanos , Idioma , Linguística
16.
Genes Dev ; 26(20): 2286-98, 2012 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-23019124

RESUMO

Embryonic stem cell (ESC) pluripotency depends on a well-characterized gene regulatory network centered on Oct4, Sox2, and Nanog. In contrast, little is known about the identity of the key coregulators and the mechanisms by which they may potentiate transcription in ESCs. Alongside core transcription factors, the orphan nuclear receptor Esrrb (estrogen-related receptor ß) is vital for the maintenance of ESC identity and furthermore is uniquely associated with the basal transcription machinery. Here, we show that Ncoa3, an essential coactivator, is required to mediate Esrrb function in ESCs. Ncoa3 interacts with Esrrb via its ligand-binding domain and bridges Esrrb to RNA polymerase II complexes. Functionally, Ncoa3 is critical for both the induction and maintenance of pluripotency. Through chromatin immunoprecipitation (ChIP) sequencing and microarray experiments, we further demonstrate that Ncoa3 shares overlapping gene regulatory functions with Esrrb and cooperates genome-wide with the Oct4-Sox2-Nanog circuitry at active enhancers to up-regulate genes involved in self-renewal and pluripotency. We propose an integrated model of transcriptional and coactivator control, mediated by Ncoa3, for the maintenance of ESC self-renewal and somatic cell reprogramming.


Assuntos
Reprogramação Celular/genética , Células-Tronco Embrionárias/citologia , Coativador 3 de Receptor Nuclear/metabolismo , Receptores de Estrogênio/metabolismo , Animais , Células COS , Proliferação de Células , Chlorocebus aethiops , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Genoma/genética , Células HEK293 , Humanos , Masculino , Camundongos , Receptores de Estrogênio/genética
17.
Proc Natl Acad Sci U S A ; 113(52): 15084-15089, 2016 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-27956631

RESUMO

Oncogenic isocitrate dehydrogenase (IDH)1 and IDH2 mutations at three hotspot arginine residues cause an enzymatic gain of function that leads to the production and accumulation of the metabolite 2-hydroxyglutarate (2HG), which contributes to the development of a number of malignancies. In the hematopoietic system, mutations in IDH1 at arginine (R) 132 and in IDH2 at R140 and R172 are commonly observed in acute myeloid leukemia, and elevated 2HG is observed in cells and serum. However, in angioimmunoblastic T-cell lymphoma (AITL), mutations are almost exclusively restricted to IDH2 R172, and levels of 2HG have not been comprehensively measured. In this study, we investigate the expression pattern of mutant IDH2 in the AITL tumor microenvironment and measure levels of 2HG in tissue and serum of AITL patients. We find that mutant IDH2 expression is restricted to the malignant T-cell component of AITL, and that 2HG is elevated in tumor tissue and serum of patients. We also investigate the differences between the three hotspot mutation sites in IDH1 and IDH2 using conditional knock-in mouse models. These studies show that in the lymphoid system, mutations in IDH2 at R172 produce high levels of 2HG compared with mutations at the other two sites and that lymphoid development is impaired in these animals. These data provide evidence that IDH2 R172 mutations may be the only variants present in AITL because of their capacity to produce significant amounts of the oncometabolite 2HG in the cell of origin of this disease.


Assuntos
Glutaratos/metabolismo , Isocitrato Desidrogenase/genética , Linfoma de Células T/imunologia , Animais , Biomarcadores Tumorais , Citometria de Fluxo , Regulação Neoplásica da Expressão Gênica , Genótipo , Humanos , Isocitrato Desidrogenase/metabolismo , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Linfócitos/metabolismo , Linfoma de Células T/metabolismo , Camundongos , Camundongos Knockout , Mutação
19.
J Neurolinguistics ; 48: 199-225, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30220790

RESUMO

Some current models of aphasia emphasize a role of short-term memory in the processing of language and propose that the language impairment in aphasia involves impairment to cognitive processes that activate and maintain representations of words over the time-period needed to support single word and multiple word tasks, including verbal span tasks. This paper reports normative data from 39 people with aphasia and 16 age-matched neurotypical controls on a test battery for aphasia that assesses effects of increased short-term/working memory load on word and sentence processing as well as effects of linguistic variations on verbal short-term memory abilities Two concepts are discussed that capture the unique potential of this test battery for research and clinical practice: specificity of diagnosis and sensitivity to all degrees of aphasia severity, including mild aphasia. An analysis is included that shows how the performance of individuals with mild aphasia who achieve normal level of performance on the Western Aphasia Battery (Kertesz, 2006) show a decline in a temporal delay condition that is greater than performance of control participants. We also report preliminary data showing differential effects of adding a time interval before a response or between items to be compared: reduced accuracy for some individuals with aphasia and improved accuracy for others. The theoretical and clinical importance of this finding is discussed, as well as the overall potential for this test battery to be used in research and as a clinical tool. Finally, we discuss the relevance of this test battery to investigate functional communication abilities in aphasia.

20.
J Neurolinguistics ; 48: 176-189, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30455550

RESUMO

Auditory-verbal short-term memory impairments are part and parcel of aphasia and interfere with linguistic processing. To date, the science about short-term memory impairments in aphasia has been generated and dominated by studying measures of accuracy, that is, span length. Because accuracy is expressed through speech, examining the speech-timing characteristics of persons with aphasia as they engage in spoken recall could reveal insights about the manner in which accuracy is achieved. Six speech-timing measures (e.g., response durations, pause durations) were elicited from the speech waveform of word span tasks from twelve people with aphasia. Speech-timing measures were compared to neuro-typical control participants. Speech-timing performance between erroneous and correct responses in the aphasia group was also examined. Across all measures, people with aphasia produced considerably longer speech-timing patterns in comparison to control participants. Memory load affected some measures in people with aphasia and control participants. Speech-timing in correct response trials was shorter than responses in erroneous trials. Memory span correlated only with one measure, namely, speech time (defined as the sum of each individual word duration in a response). Speech time also correlated with the following measures: Aphasia severity (Aphasia Quotient of the Western Aphasia Battery), spontaneous speech, and language comprehension (also measured by the Western Aphasia Battery). Some protracted speech-timing patterns in the aphasia group may be explained by a deregulation of activation-decay patterns. However, in the absence of further evidence from people with aphasia, possible issues around the sensitivity of some speech-timing measures limit firmer conclusions. Speech-timing measures are response-time measures, which have not been systematically studied in studies of short-term or working memory in aphasia and as such, can push the current boundaries of knowledge of short-term and working memory impairments in aphasia, not only in stroke related aphasia but also other neurological conditions.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA