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1.
AJNR Am J Neuroradiol ; 44(4): 474-480, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36997283

RESUMO

BACKGROUND AND PURPOSE: Flow diverters with antithrombotic coatings are increasingly used to improve the safety of flow diverter treatments of intracranial aneurysms. This study aimed to investigate the safety and short-term efficacy of the new FRED X flow diverter. MATERIALS AND METHODS: Medical charts and procedural and imaging data of a consecutive series of patients with intracranial aneurysms who were treated with the FRED X at 9 international neurovascular centers were retrospectively analyzed. RESULTS: One hundred sixty-one patients (77.6% women; mean age, 55 years) with 184 aneurysms (11.2% acutely ruptured) were included in this study. Most aneurysms were located in the anterior circulation (77.0%), most frequently at the ICA (72.7%). The FRED X was successfully implanted in all procedures. Additional coiling was performed in 29.8%. In-stent balloon angioplasty was necessary in 2.5%. The rate of major adverse events was 3.1%. Thrombotic events occurred in 7 patients (4.3%) with 4 intra- and 4 postprocedural in-stent thromboses, respectively (1 patient had both peri- and postprocedural thrombosis). Of these thrombotic events, only 2 (1.2%) led to major adverse events (ischemic strokes). Postinterventional neurologic morbidity and mortality were observed in 1.9% and 1.2%, respectively. The rate of complete aneurysm occlusion after a mean follow-up of 7.0 months was 66.0%. CONCLUSIONS: The new FRED X is a safe and feasible device for aneurysm treatment. In this retrospective multicenter study, the rate of thrombotic complications was low, and the short-term occlusion rates are satisfactory.


Assuntos
Embolização Terapêutica , Procedimentos Endovasculares , Aneurisma Intracraniano , Humanos , Feminino , Pessoa de Meia-Idade , Masculino , Resultado do Tratamento , Fibrinolíticos , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/terapia , Estudos Retrospectivos , Procedimentos Endovasculares/métodos , Stents , Embolização Terapêutica/métodos
2.
Climacteric ; 24(3): 229-235, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33527841

RESUMO

In clinical practice, micronized progesterone (MP) is frequently recommended to treat signs and symptoms of skin and hair aging in menopausal women. The aim of this comprehensive review was to evaluate whether topically or systemically applied MP may effectively prevent or slow down signs of skin and hair aging. Three out of six identified studies reported an impact of MP on skin aging markers in menopausal women. Of these, two studies reported a benefit: one for topically applied MP, another for systemically applied combined menopausal hormone therapy (MHT) comprising MP as progestogen for endometrial protection. Tolerability and safety of MP were good. However, there was no study investigating the impact of MP on menopausal scalp hair. In conclusion, delay of skin aging comprises lifestyle adjustment, antioxidants, and several esthetic procedures. In menopausal women, MHT displays beneficial effects on skin aging. There is poor quality but promising scientific evidence for MP displaying anti-aging skin effects in menopausal women. However, good quality studies are needed.


Assuntos
Terapia de Reposição de Estrogênios , Cabelo/efeitos dos fármacos , Menopausa/efeitos dos fármacos , Progesterona/administração & dosagem , Envelhecimento da Pele/efeitos dos fármacos , Administração Oral , Administração Tópica , Feminino , Humanos , Pessoa de Meia-Idade
3.
Neuroimage Clin ; 24: 102010, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31734532

RESUMO

The dynamic connectome perspective states that brain functions arise from the functional integration of distributed and/or partly overlapping networks. Diffuse low-grade gliomas (DLGG) have a slow infiltrating character. Here we addressed whether and how anatomical disconnection following DLGG growth and resection might interfere with functional resting-state connectivity, specifically in relation to picture naming. Thirty-nine native French persons with a left DLGG were included. All underwent awake surgical resection of the tumor using direct brain electrostimulation to preserve critical eloquent regions. The anatomical disconnectivity risk following the DLGG volume and the resection, and the functional connectivity of resting-state fMRI images in relation to picture naming were evaluated prior to and three months after surgery. Resting-state connectivity patterns were compared with nineteen healthy controls. It was demonstrated that picture naming was strongly dependent on the semantic network that emerged from the integration and interaction of regions within multiple resting-state brain networks, in which their specific role could be explained in the light of the broader resting-state network they take part in. It emphasized the importance of a whole brain approach with specific clinical data input, during resting-state analysis in case of lesion. Adaptive plasticity was found in secondary regions, functionally connected to regions close to the tumor and/or cavity, marked by an increased connectivity of the right and left inferior parietal lobule with the left inferior temporal gyrus. In addition, an important role was identified for the superior parietal lobe, connected with the frontal operculum, suggesting functional compensation by means of attentional resources in order to name a picture via recruitment of the frontoparietal attention network.


Assuntos
Neoplasias Encefálicas , Córtex Cerebral/fisiopatologia , Conectoma , Glioma , Rede Nervosa/fisiopatologia , Plasticidade Neuronal/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Adulto , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/cirurgia , Córtex Cerebral/diagnóstico por imagem , Feminino , Glioma/diagnóstico por imagem , Glioma/patologia , Glioma/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Rede Nervosa/diagnóstico por imagem , Procedimentos Neurocirúrgicos
4.
BMC Cardiovasc Disord ; 18(1): 41, 2018 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-29486707

RESUMO

BACKGROUND: Myxomatous mitral valve prolapse is a common cardiac abnormality. Morbus Barlow is characterized by excess myxomatous leaflet tissue, bileaflet prolapse or billowing, chordae elongation and annular dilatation with or without calcification. Extensive myxoid degeneration with destruction of the normal three-layered leaflet tissue architecture is observed histologically in such patients. Autosomal dominant inheritance with an age and sex-dependent expression has long been recognised. This review explores the current understanding of the genetics of bileaflet prolapse, with a focus on genetic analysis and the role for echocardiographical screening of the first degree relatives of affected patients. METHODS: Systematic literature searches were performed using PubMed and Embase up to September 2017. In Disse et al.'s study (study one) first degree relatives of 25 patients with Morbus Barlow who underwent mitral valve repair were screened for bileaflet valve prolapse. In Nesta et al.'s study one family with three living generations of 43 individuals with 9 confirmed cases of MVP was screened. Genotyping was performed in four families for 344 microsatellite markers from Chromosome 1 to 16. RESULTS: In study one, autosomal dominant inheritance was shown in four pedigrees. Genome-wide linkage analysis of the most informative pedigree (24 individuals, three generations) showed a significant linkage for markers mapping to chromosome 16p. Linkage to this locus was confirmed in a second family within the same study, but was excluded in the remaining two pedigrees. In study two an autosomal dominant locus was mapped to chromosome 13. 8 of the 9 individuals affected were found to suffer from bileaflet prolapse. CONCLUSIONS: Barlow's disease is a heritable trait but the genetic causes remain largely elusive. Ch16p11.2-p12.1 is the only locus proven to be associated with bileaflet prolapse. Locus 13.q31.3-q32.1 was shown to cause bileaflet as well as posterior leaflet prolapse. This review intends to make physicians aware of genetic causes of myxomatous mitral valve prolapse, thereby emphasising the importance of cardiological examination of first-degree relatives of patients with Morbus Barlow. Integrated and more comprehensive studies are needed for identification of genes involved in this heterogenic disease. Further genomic studies may facilitate more individualised and accurate risk assessment and may help to develop possible preventive stategies for patients in the future.


Assuntos
Prolapso da Valva Mitral/genética , Valva Mitral/anormalidades , Adulto , Ecocardiografia , Feminino , Marcadores Genéticos , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Hereditariedade , Humanos , Masculino , Pessoa de Meia-Idade , Valva Mitral/diagnóstico por imagem , Valva Mitral/fisiopatologia , Prolapso da Valva Mitral/diagnóstico por imagem , Prolapso da Valva Mitral/fisiopatologia , Linhagem , Prognóstico , Fatores de Risco
5.
Neurochirurgie ; 63(3): 135-141, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28506481

RESUMO

Neuropsychological care of patients suffering from an infiltrative glioma and candidates for a neurosurgery under awake condition with intraoperative functional mapping is a critical and mandatory stage in therapeutic management. It enables to estimate the functional impact of the tumor and, consequently, the efficacy of functional reorganization typically observed in these patients, not only to better predict surgery outcomes and select appropriate tasks for intraoperative functional mapping, but also to plan efficient and individualized postoperative cognitive rehabilitation strategies. Neuropsychological care management also enables patients to benefit from a solid psychological preparation both to the surgery and its associated transitory functional consequences, as well as provide a personalized psychological and emotional long-term support. Based on their solid experience in the peri-operative care of diffuse low-grade glioma patients, the authors thoroughly describe the different stages of neuropsychological management. Cognitive, emotional and language assessments typically used by the authors around and during surgery are reported, and different possible avenues of improvement are further discussed.


Assuntos
Mapeamento Encefálico , Neoplasias Encefálicas/fisiopatologia , Cognição , Glioma/fisiopatologia , Monitorização Neurofisiológica Intraoperatória , Idioma , Monitorização Intraoperatória , Encéfalo/cirurgia , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/cirurgia , Cognição/fisiologia , Glioma/diagnóstico , Glioma/patologia , Glioma/cirurgia , Humanos , Monitorização Intraoperatória/métodos , Procedimentos Neurocirúrgicos/métodos , Vigília/fisiologia
6.
Neurochirurgie ; 63(3): 250-258, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28161011

RESUMO

OBJECTIVE: Incidentally discovered diffuse low-grade gliomas progress in a fashion similar to their symptomatic counterparts. Their early detection allows more effective pre-emptive and individualized oncological treatment. We assessed the safety and efficacy of maximal safe resection according to functional boundaries for incidental diffuse low-grade gliomas in eloquent areas. MATERIAL AND METHODS: Two-centre retrospective series of adult patients with incidental diffuse low-grade gliomas located within/close to eloquent areas in the dominant hemisphere, treated with maximal surgical resection according to functional boundaries under intraoperative functional cortico-subcortical monitoring under awake conditions, and with a minimal follow-up of 24months. RESULTS: The series included 19 patients (8 men, 11 women) with no preoperative neurological deficit but with a radiologically enlarged glioma. No intraoperative seizure, postoperative infection, haematoma or wound-healing problem was observed. In the immediate postsurgical period, a transient neurological worsening occurred in 10 patients. The resection (mean rate 96.4%; range, 82.4-100) was supratotal in 5 cases, total in 5 cases, subtotal in 7 cases, and partial in 2 cases. Six months after surgery, all patients recovered after functional rehabilitation, with no permanent neurological deficit, Karnofsky Performance Status was 100 (except for one patient who received early postoperative radiotherapy) and no seizures were observed. The survival without progression requiring oncological treatment was significantly longer in patients with a total/supratotal resection than in patients with a partial/subtotal resection. CONCLUSIONS: These results suggest the reproducibility, safety, and effectiveness of an early maximal functionally based resection within cortico-subcortical functional boundaries for incidental diffuse low-grade gliomas in adults in centres hyperspecialized in surgical neuro-oncology.


Assuntos
Neoplasias Encefálicas/cirurgia , Epilepsia/cirurgia , Glioma/cirurgia , Adulto , Encéfalo/cirurgia , Mapeamento Encefálico/métodos , Neoplasias Encefálicas/complicações , Neoplasias Encefálicas/diagnóstico , Estimulação Elétrica/métodos , Epilepsia/etiologia , Feminino , Glioma/complicações , Glioma/diagnóstico , Humanos , Monitorização Neurofisiológica Intraoperatória , Masculino , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos/métodos , Complicações Pós-Operatórias/prevenção & controle , Estudos Retrospectivos , Resultado do Tratamento , Vigília/fisiologia
7.
Oncogene ; 36(7): 933-941, 2017 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-27477692

RESUMO

Tumor surveillance of natural killer (NK) cells is mediated by the cytotoxicity receptor natural-killer group 2 member D (NKG2D). Ligands for NKG2D are generally not expressed on healthy cells, but induced on the surface of malignant cells. To date, NKG2D ligand (NKG2D-L) induction was mainly described to depend on the activation of the DNA damage response, although the molecular mechanisms that regulate NKG2D-L expression remain largely unknown. Here, we show that the acetyltransferases CBP (CREB-binding protein) and p300 play a crucial role in the regulation of NKG2D-L on tumor cells. Loss of CBP/p300 decreased the basal cell surface expression of human ligands and reduced the upregulation of MICA/B and ULBP2 in response to histone deacetylase inhibitors or DNA damage. Furthermore, CBP/P300 deficiency abrogated the sensitivity of stressed cells to NK cell-mediated killing. CBP/p300 were also identified as major regulators of mouse NKG2D ligand RAE-1 in vitro and in vivo using the Eµ-Myc lymphoma model. Mechanistically, we observed an enhanced activation of the CBP/p300 binding transcription factor CREB (cAMP response element-binding protein) correlating to the NKG2D-L upregulation. Moreover, increased binding of CREB and CBP/p300 to NKG2D-L promoters and elevated histone acetylation were detectable. This study provides strong evidence for a major role of CBP and p300 in orchestrating NKG2D-L induction and consequently immunosurveillance of tumors in mice and humans. These findings might help to develop novel immunotherapeutic approaches against cancer.


Assuntos
Antígenos de Histocompatibilidade Classe I/genética , Peptídeos e Proteínas de Sinalização Intercelular/genética , Linfoma/metabolismo , Subfamília K de Receptores Semelhantes a Lectina de Células NK/metabolismo , Proteínas Associadas à Matriz Nuclear/genética , Proteínas de Transporte Nucleocitoplasmático/genética , Fatores de Transcrição de p300-CBP/metabolismo , Acetilação , Animais , Células Cultivadas , Modelos Animais de Doenças , Proteínas Ligadas por GPI/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Linfoma/genética , Linfoma/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Subfamília K de Receptores Semelhantes a Lectina de Células NK/genética , Transcrição Gênica , Fatores de Transcrição de p300-CBP/genética
8.
Am J Transplant ; 16(12): 3322-3337, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27529775

RESUMO

The pathophysiological importance of the immunogenicity of damage-associated molecular patterns (DAMPs) has been pinpointed by their identification as triggers of allograft rejection following release from dying cells, such as after ischemia-reperfusion injury. In cancers, however, this strong trigger of a specific immune response gives rise to the success of cancer immunotherapy. Here, we review the recently literature on the pathophysiological importance of DAMP release and discuss the implications of these processes for allograft rejection and cancer immunotherapy, revealing a striking mechanistic overlap. We conclude that these two fields share a common mechanistic basis of regulated necrosis and inflammation, the molecular characterization of which may be helpful for both oncologists and the transplant community.


Assuntos
Rejeição de Enxerto/imunologia , Inflamação/fisiopatologia , Neoplasias/imunologia , Traumatismo por Reperfusão/imunologia , Aloenxertos , Animais , Rejeição de Enxerto/patologia , Humanos , Necrose , Neoplasias/patologia , Traumatismo por Reperfusão/patologia
9.
Am J Transplant ; 16(12): 3338-3361, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27421829

RESUMO

Upon solid organ transplantation and during cancer immunotherapy, cellular stress responses result in the release of damage-associated molecular patterns (DAMPs). The various cellular stresses have been characterized in detail over the last decades, but a unifying classification based on clinically important aspects is lacking. Here, we provide an in-depth review of the most recent literature along with a unifying concept of the danger/injury model, suggest a classification of DAMPs, and review the recently elaborated mechanisms that result in the emission of such factors. We further point out the differences in DAMP responses including the release following a heat shock pattern, endoplasmic reticulum stress, DNA damage-mediated DAMP release, and discuss the diverse pathways of regulated necrosis in this respect. The understanding of various forms of DAMPs and the consequences of their different release patterns are prerequisite to associate serum markers of cellular stresses with clinical outcomes.


Assuntos
Estresse do Retículo Endoplasmático , Rejeição de Enxerto/etiologia , Inflamação/fisiopatologia , Transplante de Órgãos/efeitos adversos , Animais , Humanos , Necrose
11.
Artigo em Inglês | MEDLINE | ID: mdl-21467137

RESUMO

Chromatin is nonrandomly distributed in nuclear space, yet the functional significance of this remains unclear. Here, we make use of transgenes carrying developmentally regulated promoters to study subnuclear gene positioning during the development of Caenorhabditis elegans. We found that small transgenes (copy number ≤50) are randomly distributed in early embryonic nuclei, independent of promoter activity. However, in differentiated tissues, these same transgenes occupied specific subnuclear positions: When promoters are repressed, transgenes are found at the nuclear periphery, whereas active, developmentally regulated promoters are enriched in the nuclear core. The absence of specific transgene positioning in embryonic nuclei does not reflect an absence of proteins that mediate perinuclear sequestration: Embryonic nuclei are able to sequester much larger transgene arrays (copy number 300-500) at the periphery. This size-dependent peripheral positioning of gene arrays in early embryos correlates with the accumulation of heterochromatic marks (H3K9me3 and H3K27me3) on large arrays. Interestingly, depletion of nuclear lamina components caused release of arrays from the nuclear envelope and interfered with their efficient silencing. Our results suggest that developmentally silenced chromatin binds the nuclear lamina in a manner correlated with the deposition of heterochromatic marks. Peripheral sequestration of chromatin may, in turn, support the maintenance of silencing.


Assuntos
Caenorhabditis elegans/genética , Dosagem de Genes/genética , Heterocromatina/metabolismo , Laminas/metabolismo , Membrana Nuclear/metabolismo , Sequências Repetitivas de Ácido Nucleico/genética , Transgenes/genética , Animais , Caenorhabditis elegans/embriologia , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Diferenciação Celular/genética , Embrião não Mamífero/citologia , Embrião não Mamífero/metabolismo , Desenvolvimento Embrionário/genética , Genes de Helmintos/genética , Modelos Genéticos , Mutação/genética , Análise de Sequência com Séries de Oligonucleotídeos , Regiões Promotoras Genéticas , Processos Estocásticos
12.
Praxis (Bern 1994) ; 97(10): 569-70, 2008 May 14.
Artigo em Alemão | MEDLINE | ID: mdl-18595374

RESUMO

We report a case of a 56-year old patient with coronary heart disease and subacute myocardial infarction who presented with acute sialadenitis after twice undergoing coronary angiography. Acute sialadenitis ('iodide mumps') after exposure to contrast medium is characterized by a fast, painless and bilateral swelling of the salivary glands. It is usually self-limiting but can occur after re-exposure to the contrast agent.


Assuntos
Meios de Contraste/efeitos adversos , Angiografia Coronária/efeitos adversos , Estenose Coronária/diagnóstico por imagem , Iopamidol/análogos & derivados , Parotidite/induzido quimicamente , Angioplastia Coronária com Balão , Estenose Coronária/terapia , Diagnóstico Diferencial , Humanos , Iopamidol/efeitos adversos , Masculino , Pessoa de Meia-Idade , Stents
13.
Praxis (Bern 1994) ; 94(19): 765-9, 2005 May 11.
Artigo em Alemão | MEDLINE | ID: mdl-15940907

RESUMO

Sepsis is the most important reason for death among intensive care patients. This review will cover the actual definition of septic shock, and the difficulties regarding the diagnosis of sepsis. The principles of management of sepsis, the recently established principles as early goal directed therapy, low dose steroid substitution, insulin therapy, and the activated protein C are discussed.


Assuntos
Choque Séptico/diagnóstico , Corticosteroides/administração & dosagem , Fármacos Cardiovasculares/administração & dosagem , Ensaios Clínicos como Assunto , Terapia Combinada , Cuidados Críticos , Relação Dose-Resposta a Droga , Quimioterapia Combinada , Hemodinâmica/efeitos dos fármacos , Mortalidade Hospitalar , Humanos , Insulina/administração & dosagem , Oxigenoterapia , Proteína C/administração & dosagem , Proteínas Recombinantes/administração & dosagem , Choque Séptico/tratamento farmacológico , Choque Séptico/mortalidade , Taxa de Sobrevida
14.
J Acoust Soc Am ; 117(4 Pt 1): 2090-9, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15898650

RESUMO

The classical description of porous media as a homogeneous equivalent fluid is presented, and its foundations on the homogenization method is introduced and applied to the numerical prediction model for a periodic porous medium composed by face centered cubic sphere packing on which measurements have been made. The results are compared with existing numerical results in the literature and with new and experimental data.

16.
Cell Mol Life Sci ; 60(11): 2303-18, 2003 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-14625677

RESUMO

Most of the human genome is compacted into heterochromatin, a form that encompasses multiple forms of inactive chromatin structure. Transcriptional silencing mechanisms in budding and fission yeasts have provided genetically tractable models for understanding heritably repressed chromatin. These silent domains are typically found in regions of repetitive DNA, that is, either adjacent to centromeres or telomeres or within the tandemly repeated ribosomal DNA array. Here we address the mechanisms of centromeric, telomeric and locus-specific gene silencing, comparing simple and complex animals with yeast. Some aspects are universally shared, such as histone-tail modifications, while others are unique to either centromeres or telomeres. These may reflect roles for heterochromatin in other chromosomal functions, like kinetochore attachment and DNA ends protection.


Assuntos
Centrômero/fisiologia , Inativação Gênica , Telômero/fisiologia , Animais , Heterocromatina/fisiologia , Histona Desacetilases/fisiologia , Humanos , Metilação , Interferência de RNA , Saccharomycetales/genética , Schizosaccharomyces/genética , Proteínas Reguladoras de Informação Silenciosa de Saccharomyces cerevisiae/fisiologia , Sirtuína 2 , Sirtuínas/fisiologia
17.
Nature ; 414(6865): 768-73, 2001 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-11742404

RESUMO

Overexpression of the proto-oncogene c-myc has been implicated in the genesis of diverse human tumours. c-Myc seems to regulate diverse biological processes, but its role in tumorigenesis and normal physiology remains enigmatic. Here we report the generation of an allelic series of mice in which c-myc expression is incrementally reduced to zero. Fibroblasts from these mice show reduced proliferation and after complete loss of c-Myc function they exit the cell cycle. We show that Myc activity is not needed for cellular growth but does determine the percentage of activated T cells that re-enter the cell cycle. In vivo, reduction of c-Myc levels results in reduced body mass owing to multiorgan hypoplasia, in contrast to Drosophila c-myc mutants, which are smaller as a result of hypotrophy. We find that c-myc substitutes for c-myc in fibroblasts, indicating they have similar biological activities. This suggests there may be fundamental differences in the mechanisms by which mammals and insects control body size. We propose that in mammals c-Myc controls the decision to divide or not to divide and thereby functions as a crucial mediator of signals that determine organ and body size.


Assuntos
Genes cdc , Genes myc/fisiologia , Linfócitos T/citologia , Animais , Constituição Corporal/genética , Contagem de Células , Ciclo Celular/fisiologia , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/fisiologia , Divisão Celular/fisiologia , Tamanho Celular , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p27 , Drosophila , Embrião de Mamíferos/citologia , Embrião não Mamífero , Fibroblastos , Marcação de Genes , Camundongos , Proto-Oncogene Mas , Especificidade da Espécie , Linfócitos T/imunologia , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/fisiologia
18.
Science ; 294(5549): 2181-6, 2001 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-11739961

RESUMO

Little is known about the dynamics of chromosomes in interphase nuclei. By tagging four chromosomal regions with a green fluorescent protein fusion to lac repressor, we monitored the movement and subnuclear position of specific sites in the yeast genome, sampling at short time intervals. We found that early and late origins of replication are highly mobile in G1 phase, frequently moving at or faster than 0.5 micrometers/10 seconds, in an energy-dependent fashion. The rapid diffusive movement of chromatin detected in G1 becomes constrained in S phase through a mechanism dependent on active DNA replication. In contrast, telomeres and centromeres provide replication-independent constraint on chromatin movement in both G1 and S phases.


Assuntos
Cromatina/fisiologia , Cromossomos Fúngicos/fisiologia , Interfase , Saccharomyces cerevisiae/fisiologia , Trifosfato de Adenosina/metabolismo , Núcleo Celular/fisiologia , Centrômero/fisiologia , Replicação do DNA , DNA Fúngico/biossíntese , Fase G1 , Proteínas de Fluorescência Verde , Proteínas Luminescentes , Filmes Cinematográficos , Mutação , Membrana Nuclear/fisiologia , Origem de Replicação , Fase S , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Telômero/fisiologia
19.
Gene ; 279(1): 1-16, 2001 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-11722841

RESUMO

Silent or heritably repressed genes constitute the major fraction of genetic information in higher eukaryotic cells. Budding yeast has very little consecutively repressed DNA, but what exists has served as a paradigm for the molecular analysis of heterochromatin. The major structural constituents of repressed chromatin in yeast are the four core histones and three large chromatin factors called Silent information regulators 2, 3 and 4. How these components assemble DNA into a state that is refractory to transcription remains a mystery. Nonetheless, there have been many recent insights into their molecular structures. This review examines the impact of these results on our understanding of silencing function in budding yeast.


Assuntos
Proteínas Fúngicas/genética , Saccharomycetales/genética , Proteínas Reguladoras de Informação Silenciosa de Saccharomyces cerevisiae , Transativadores/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Histona Desacetilases/genética , Histona Desacetilases/metabolismo , Sirtuína 2 , Sirtuínas , Transativadores/metabolismo , Transcrição Gênica
20.
Trends Cell Biol ; 11(12): 519-25, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11719059

RESUMO

The positioning of chromosomal domains in the interphase nucleus is proposed to facilitate gene regulation in simple cells such as yeasts and to coordinate patterns of gene expression and activation of origins of replication during cell differentiation in complex organisms. Over the past 10-12 years, detailed information on the organization of interphase chromosomes has accumulated from three-dimensional microscopy of fixed cells labeled by in situ hybridization and immunofluorescence techniques. Recently, time-lapse fluorescence microscopy of GFP-tagged domains has shown that interphase chromatin can be highly dynamic, moving distances >0.5 microm within seconds. Novel fluorescence techniques show that most nuclear proteins are also highly mobile. Both the rapid oscillations of chromatin and long-range movements of chromosomes suggest new mechanisms for spatial and temporal control of transcription and other nuclear events.


Assuntos
Núcleo Celular/metabolismo , Núcleo Celular/ultraestrutura , Cromossomos/metabolismo , Microscopia de Fluorescência/métodos , Telômero/ultraestrutura , Animais , Centrômero/metabolismo , Centrômero/ultraestrutura , Cromatina/metabolismo , Cromatina/ultraestrutura , Cromossomos/ultraestrutura , Replicação do DNA/fisiologia , Humanos , Interfase/fisiologia , Movimento/fisiologia , Ribossomos/metabolismo , Ribossomos/ultraestrutura , Telômero/metabolismo , Fatores de Tempo
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