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Searches for the lepton number violating K^{+}âπ^{-}µ^{+}e^{+} decay and the lepton flavor violating K^{+}âπ^{+}µ^{-}e^{+} and π^{0}âµ^{-}e^{+} decays are reported using data collected by the NA62 experiment at CERN in 2017-2018. No evidence for these decays is found and upper limits of the branching ratios are obtained at 90% confidence level: B(K^{+}âπ^{-}µ^{+}e^{+})<4.2×10^{-11}, B(K^{+}âπ^{+}µ^{-}e^{+})<6.6×10^{-11} and B(π^{0}âµ^{-}e^{+})<3.2×10^{-10}. These results improve by 1 order of magnitude over previous results for these decay modes.
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We present a customized small-core double-clad photonic crystal fiber for spectral and fluorescence lifetime measurements of human samples. In this Letter, the new fiber has been characterized on different fluorophores and samples of human brain tumor; a comparison to a bi-fiber homemade system and a commercial fiber probe was made.
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While recent evidence strongly suggests that the third complementarity determining regions (CDR3s) of T cell receptors (TCRs) directly contact antigenic peptides bound to major histocompatibility complex (MHC) molecules, the nature of other TCR contact(s) is less clear. Here we probe the extent to which different antigens can affect this interaction by comparing the responses of T cells bearing structurally related TCRs to cytochrome c peptides and staphylococcal enterotoxin A (SEA) presented by 13 mutant antigen-presenting cell (APC) lines. Each APC expresses a class II MHC molecule (I-Ek) with a single substitution of an amino acid residue predicted to be located on the MHC alpha helices and to point "up" towards the TCR. We find that very limited changes (even a single amino acid) in either a CDR3 loop of the TCR or in a contact residue of the antigenic peptide can have a profound effect on relatively distant TCR/MHC interactions. The extent of these effects can be as great as that observed between T cells bearing entirely different TCRs and recognizing different peptides. We also find that superantigen presentation entails a distinct mode of TCR/MHC interaction compared with peptide presentation. These data suggest that TCR/MHC contacts can be made in a variety of ways between the same TCR and MHC, with the final configuration apparently dominated by the antigen. These observations suggest a molecular basis for recent reports in which either peptide analogues or superantigens trigger distinct pathways of T cell activation.
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Antígenos/imunologia , Antígenos de Histocompatibilidade Classe II/metabolismo , Peptídeos/imunologia , Receptores de Antígenos de Linfócitos T/metabolismo , Linfócitos T/imunologia , Sequência de Aminoácidos , Animais , Células Apresentadoras de Antígenos/imunologia , Células Apresentadoras de Antígenos/metabolismo , Células CHO , Linhagem Celular , Cricetinae , Grupo dos Citocromos c/imunologia , Enterotoxinas/imunologia , Antígenos de Histocompatibilidade Classe II/genética , Antígenos de Histocompatibilidade Classe II/imunologia , Hibridomas , Dados de Sequência Molecular , Mutação , Receptores de Antígenos de Linfócitos T/química , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Staphylococcus aureus/imunologia , Linfócitos T/metabolismoRESUMO
The interaction of the T cell receptor for antigen (TCR) with its antigen-major histocompatibility complex ligand is difficult to study because both are cell surface multimers. The TCR consists of two chains (alpha and beta) that are complexed to the five or more nonpolymorphic CD3 polypeptides. A soluble form of the TCR was engineered by replacing the carboxyl termini of alpha and beta with signal sequences from lipid-linked proteins, making them susceptible to enzymatic cleavage. In this manner, TCR heterodimers can be expressed independently of the CD3 polypeptides and in significant quantities (0.5 milligram per week). This technique seems generalizable to biochemical and structural studies of many other cell surface molecules as well.
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Receptores de Antígenos de Linfócitos T/genética , Fosfatase Alcalina/genética , Sequência de Aminoácidos , Animais , Antígenos de Diferenciação de Linfócitos T/genética , Complexo CD3 , Antígenos CD55 , Linhagem Celular , Proteínas Inativadoras do Complemento/genética , Feminino , Humanos , Substâncias Macromoleculares , Proteínas de Membrana/genética , Dados de Sequência Molecular , Placenta/enzimologia , Gravidez , Sinais Direcionadores de Proteínas/genética , TransfecçãoRESUMO
Apoptosis is implicated in the generation and resolution of inflammation in response to bacterial pathogens. All bacterial pathogens produce lipoproteins (BLPs), which trigger the innate immune response. BLPs were found to induce apoptosis in THP-1 monocytic cells through human Toll-like receptor-2 (hTLR2). BLPs also initiated apoptosis in an epithelial cell line transfected with hTLR2. In addition, BLPs stimulated nuclear factor-kappaB, a transcriptional activator of multiple host defense genes, and activated the respiratory burst through hTLR2. Thus, hTLR2 is a molecular link between microbial products, apoptosis, and host defense mechanisms.
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Apoptose , Proteínas de Bactérias/farmacologia , Proteínas de Drosophila , Lipoproteínas/farmacologia , Glicoproteínas de Membrana/metabolismo , Monócitos/citologia , Receptores de Superfície Celular/metabolismo , Anticorpos Monoclonais , Proteínas de Bactérias/metabolismo , Linhagem Celular/metabolismo , Cicloeximida/farmacologia , Citotoxicidade Imunológica , Genes Reporter , Humanos , Receptores de Lipopolissacarídeos/análise , Lipopolissacarídeos/imunologia , Lipoproteínas/metabolismo , Glicoproteínas de Membrana/imunologia , Monócitos/imunologia , Monócitos/metabolismo , NF-kappa B/metabolismo , Inibidores da Síntese de Proteínas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Receptores de Superfície Celular/imunologia , Transdução de Sinais , Acetato de Tetradecanoilforbol/farmacologia , Receptor 2 Toll-Like , Receptores Toll-Like , Transfecção , Células Tumorais CultivadasRESUMO
RATIONALE: Arterial vasospasm has rarely been reported following temporal lobectomy for intractable epilepsy. CASE PRESENTATION: A 31-year-old patient presented with a global aphasia 2 days after a left dominant anteromesial temporal lobectomy for intractable epilepsy. Magnetic resonance imaging on 5th post-operative day revealed severe narrowing of M1 segment of the left middle cerebral artery (MCA) and Transcranial Doppler (TCD) ultrasonography an increased velocity of the MCA that suggested a severe vasospasm. The patient received continuous intravenous hyperhydratation and nimodipine; aphasia improved within 24 h and resolved completely within 6 weeks, associated with velocity reduction on control TCD. CONCLUSION: Transient vasospasm is a likely underestimated cause of focal deficit following temporomesial resection that deserves appropriate treatment.
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Epilepsia do Lobo Temporal/cirurgia , Procedimentos Neurocirúrgicos/efeitos adversos , Complicações Pós-Operatórias/etiologia , Lobo Temporal/cirurgia , Vasoespasmo Intracraniano/etiologia , Adulto , Artérias Cerebrais/patologia , Epilepsia do Lobo Temporal/patologia , Humanos , Masculino , Procedimentos Neurocirúrgicos/métodos , Complicações Pós-Operatórias/patologia , Lobo Temporal/patologia , Resultado do Tratamento , Vasoespasmo Intracraniano/patologiaRESUMO
We report the results of an investigation carried out on the activity of functional neurosurgery of the cranial nerves in the French-speaking countries, based on the analysis of a questionnaire addressed to all the members of the SNCLF. Eighteen centers responded to this questionnaire, which showed that activities and indications varied greatly from one unit to another. The results appear homogeneous and comparable with those reported in the literature. The questionnaire sought to provide a global perspective, open to the comments and questions of all responders on the various techniques raised, with the objective of establishing a common decisional tree for these pathologies and providing if possible to a consensus for better dissemination of these therapies.
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Doenças dos Nervos Cranianos/patologia , Doenças dos Nervos Cranianos/cirurgia , Nervos Cranianos/patologia , Nervos Cranianos/cirurgia , Neurocirurgia/estatística & dados numéricos , Procedimentos Neurocirúrgicos/estatística & dados numéricos , Coleta de Dados , Espasmo Hemifacial/cirurgia , Humanos , Inquéritos e Questionários , Neuralgia do Trigêmeo/cirurgiaRESUMO
Drug-resistant mesial temporal lobe epilepsy with hippocampal sclerosis is associated with anatomical, ultrastructural and functional changes that facilitate generation and spread of epileptic seizures. Intrahippocampal circuits are modified in their transversal lamellar and longitudinal translamellar organization. Neuronal death and the neuroplasticity of surviving cells contribute to major phenomena: an increased hyperexcitability of the hippocampal formation and an increased synchronization of its principal cells. Selective disruption of the epileptic networks that are involved in mesial temporal lobe epilepsy may have a therapeutic effect. We present here the preliminary results of a selective intrahippocampal transection in a chronic model of mesial temporal lobe epilepsy after focal injection of kainic acid in adult mice. A complete transection of the hippocampal formation (including dentate gyrus and hippocampus proper, sparing the fimbria) results in a blockade of ictal activities spread from the generator, a reduction in their frequency and an increase in their duration. In contrast, after a transection sparing the dentate gyrus and hilus, no modification was noted. In this model of mesial temporal lobe epilepsy, longitudinally projecting axonal circuits of the dentate gyrus and hilus appear to be implicated in generation, propagation and interruption of ictal activities within hippocampal formation.
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Epilepsia do Lobo Temporal/fisiopatologia , Epilepsia do Lobo Temporal/cirurgia , Hipocampo/cirurgia , Procedimentos Neurocirúrgicos , Animais , Doença Crônica , Modelos Animais de Doenças , Epilepsia do Lobo Temporal/patologia , Agonistas de Aminoácidos Excitatórios , Hipocampo/patologia , Ácido Caínico , Excitação Neurológica/fisiologia , Camundongos , Plasticidade Neuronal/fisiologiaRESUMO
The surgical treatment of epilepsy requires careful preparation and presents a certain number of technical specificities. The neurosurgeon must master not only the technical aspects but also the therapeutic and functional trade-off in order to modulate the procedure according to morphological and electrophysiological intraoperative data. A large number of technical variants have been developed to correspond to epileptological or functional anatomical considerations. Until this point, the choice of a particular technique does not seem to have a significant impact on the therapeutic effectiveness of surgery, and differences in results can be related to the presurgical evaluation and surgical indications. On the other hand, technical development promises to play an important role in limiting the long-term neurocognitive consequences of surgery.
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Córtex Cerebral/cirurgia , Procedimentos Neurocirúrgicos/métodos , Eletroencefalografia , Humanos , Lobo Temporal/cirurgiaRESUMO
BACKGROUND AND PURPOSE: Taylor-type focal cortical dysplasias (TTFCD) represent a particular pathological entity responsible for severe drug-resistant epilepsy of extratemporal location. Epilepsy can be surgically cured if complete removal of the lesion can be performed. However, identification on imaging may be difficult and negative standard MRIs are not rare. The frequent location of TTFCD in the central region restrains the possibilities of complete resection. We report a series of patients operated on for intractable epilepsy associated with TTFCD in the central area. PATIENTS AND METHODS: Between 2000 and 2006, of 34 consecutive patients with TTFCD, 17 had a lesion located in the central area. MRI was considered normal in eight, although in five a subtle gyral abnormality was disclosed on further analysis. A (18)FDG PET scan performed in 16 cases demonstrated focal hypometabolism in 15 that correlated with abnormalities on MRI when visible. SEEG performed in 13 cases revealed typical abnormalities for TTFCD in 10 cases. At resection, cortical and subcortical stimulations of the dysplastic cortex did not elicit a motor response. RESULTS: Postoperative motor or sensory deficit was observed in 13 patients--severe in four--which subsequently resolved completely in seven. Six patients had a minor permanent, motor or sensory deficit. Four patients were reoperated for seizure recurrence and residual dysplastic tissue was found at reoperation in three cases. Average postoperative follow-up was 3.7 years. Sixteen patients (94%) were in Engel Class I (65% in Class IA). CONCLUSION: This study suggests that surgical resection of central region TTFCD may be associated with favorable seizure outcome and no or minor functional permanent disability. In cases of seizure relapse, reoperation can be performed without further permanent deficit and lead to seizure-free outcome. Future techniques for intraoperative detection of these lesions could optimize their complete resection in functional areas.
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Córtex Cerebral/patologia , Córtex Cerebral/cirurgia , Epilepsia/patologia , Epilepsia/cirurgia , Procedimentos Neurocirúrgicos , Adolescente , Adulto , Córtex Cerebral/diagnóstico por imagem , Criança , Resistência a Medicamentos , Eletroencefalografia , Epilepsia/diagnóstico , Feminino , Fluordesoxiglucose F18 , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Tomografia por Emissão de Pósitrons , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/psicologia , Compostos Radiofarmacêuticos , Resultado do TratamentoRESUMO
Frontal lobe epilepsy surgery is the second most common surgery performed for drug-resistant partial epilepsy. We investigated the longitudinal outcome in a cohort of patients investigated since 1990 with SEEG and modern diagnostic techniques. We reviewed 105 patients who underwent surgery between 1990 and 2005 (mean follow-up, six years; range: one to 17 years) and analyzed the year-per-year follow-up according to Engel's classification. Favorable outcome (Class I) was observed for 70% and this result was stable at least five years after surgery. More than 90% of patients with lesion-related epilepsies (focal cortical dysplasia and dysembryoplastic neuroepithelial tumors) became seizure-free. Less than 50% of patients classified as having cryptogenic epilepsy (defined as normal imaging and neuropathology on surgical specimen) had a favorable outcome. Permanent neurological sequelae were subtle and rare, especially after surgery for dysplasia in eloquent cortex (primary motor cortex). Our data indicate that frontal surgery is a successful treatment in patients when electrophysiological and morphological investigations demonstrate a well-defined epileptogenic zone or lesion to be surgically resected. Progress in electrophysiological and brain-imaging techniques will further improve the selection of frontal lobe epilepsy surgery candidates.
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Epilepsia do Lobo Frontal/cirurgia , Procedimentos Neurocirúrgicos , Adolescente , Adulto , Criança , Pré-Escolar , Estudos de Coortes , Dominância Cerebral/fisiologia , Eletroencefalografia , Eletrofisiologia , Epilepsia do Lobo Frontal/etiologia , Epilepsia do Lobo Frontal/patologia , Feminino , Seguimentos , Lateralidade Funcional , Humanos , Lactente , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Córtex Motor/patologia , Procedimentos Neurocirúrgicos/métodos , Seleção de Pacientes , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/psicologia , Convulsões/epidemiologia , Convulsões/fisiopatologia , Resultado do TratamentoRESUMO
BACKGROUND AND PURPOSE: Animal models have provided very valuable data to specify the physiopathological mechanisms of the various forms of epilepsy. However, the question arises of knowing which of these experimental results are relevant to the human epileptic brain. The development of epileptic surgery makes it possible to directly study the functional properties of human brain tissue in vitro and to analyze the mechanisms underlying seizures and epileptogenesis. We review some of the results obtained over the last few years in our laboratory based on electrophysiological, immunocytochemical and molecular experiments conducted on human brain tissue. RESULTS: This review covers a number of the mechanisms of neuronal synchronizations generating epileptiform discharges, including the role of electrical synapses connecting the inhibitory interneurons, particularly in Taylor-type focal cortical dysplasia and the functional lability of GABAergic inhibition in epileptogenic human cortical tissue, which may sustain triggering and propagation of seizures. Some of these mechanisms have not been described in animal models. CONCLUSIONS: Studies on human tissue, when carefully designed, are necessary to validate the data collected on animal models and will continue to provide us with new and important information on the cerebral changes related to epilepsy. Moreover, these studies allow development of a class of antiepileptic drugs that have a completely new mechanism of action, which could be effective in the treatment of drug-resistant epilepsies.
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Epilepsia/patologia , Neurônios/patologia , Córtex Cerebral/patologia , Córtex Cerebral/fisiopatologia , Eletrofisiologia , Epilepsia/fisiopatologia , Humanos , Técnicas In Vitro , Interneurônios/fisiologia , Receptores de GABA-A/fisiologia , Convulsões/patologia , Ácido gama-Aminobutírico/fisiologiaRESUMO
Surgical resections for intractable epilepsy are generally associated with a high risk of permanent neurological deficit and a poor rate of seizure control. We present a series of 89 patients operated on from 1992 through 2007 for drug-resistant partial epilepsy, in whom surgery was performed in a functional area of the brain: the central (sensorimotor and supplementary motor areas) region in 48 cases, posterior regions (parietal and occipital) in 27, the insula in eight, and the language areas in six. Epilepsy was cryptogenic in 12 patients, and lesion-related in 77: malformation of cortical development in 43, tumor in 17, perinatal cicatrix in 13, vascular lesion in three, and another prenatal lesion in one. Seventy patients underwent stereoelectroencephalographic (SEEG) exploration. The surgical procedure was resective (lesionectomy or SEEG-guided corticectomy) in 83 patients and multiple stereotactic thermocoagulations in six. Ten patients were reoperated because of early seizure recurrence. A postoperative complication was observed in 12 patients. Postoperative deficits were observed in 54 patients (61%) and resolved completely in 29. In 25, a permanent deficit persisted, minor in 19 and moderate to severe in six, which did not correlate with localization or etiology. With a one-year follow-up in 74 patients (mean, 3.6 years), 53 (72%) were in Engel's class I, including 38 (51%) in class IA. Seizure outcome was significantly associated with etiology: 93% of Taylor-type focal cortical dysplasia, whereas only 40% of cryptogenic epilepsies were in class I (p<0.05). This suggests that resective or disconnective surgery for intractable partial epilepsy in functional areas of the brain may be followed by excellent results on seizures and a moderate risk of permanent neurological sequelae.
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Encéfalo/fisiologia , Encéfalo/cirurgia , Epilepsia/cirurgia , Procedimentos Neurocirúrgicos , Adolescente , Adulto , Encéfalo/fisiopatologia , Malformações Vasculares do Sistema Nervoso Central/patologia , Malformações Vasculares do Sistema Nervoso Central/cirurgia , Criança , Pré-Escolar , Resistência a Medicamentos , Eletroencefalografia , Epilepsia/fisiopatologia , Feminino , Seguimentos , Humanos , Lactente , Masculino , Córtex Motor/cirurgia , Lobo Occipital/patologia , Lobo Parietal/cirurgia , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/fisiopatologia , Complicações Pós-Operatórias/psicologia , Convulsões/epidemiologia , Convulsões/cirurgia , Córtex Somatossensorial/cirurgia , Análise de Sobrevida , Resultado do TratamentoRESUMO
We report here the results of the first survey on epilepsy surgery activity in France. Data from a questionnaire sent to 17 centers practicing epilepsy surgery were analyzed. All centers responded; however, all items were not completely documented. Over 50 years, more than 5000 patients have been operated on for drug-resistant epilepsy and more than 3000 patients underwent some invasive monitoring, most often SEEG. Currently, nearly 400 patients (including more than 100 children) are operated on yearly for epilepsy in France. Over a study period varying among centers (from two to 20 years; mean, 9.5 years), results from more than 2000 patients including one-third children were analyzed. Important differences between adults and children, respectively, were observed in terms of location (temporal: 72% versus 4.3%; frontal: 12% versus 28%; central: 2% versus 11%), etiology (hippocampal sclerosis: 41% versus 2%; tumors 20% versus 61%); and procedures (cortectomy: 50% versus 23%; lesionectomy: 8% versus 59%), although overall results were identical (seizure-free rates following temporal lobe surgery: 80.6% versus 79%; following extratemporal surgery: 65.9% versus 65%). In adults, the best results were observed following temporomesial (TM) resection associated with hippocampal sclerosis or other lesions (class I: 83% and 79%, respectively), temporal neocortical (TNC) lesional (82%), while resections for cryptogenic temporal resections were followed by 69% (TM) and 63% (TNC) class I outcome. Extratemporal lesional resections were associated with 71% class I outcome and cryptogenic 43%. In children, the best results were obtained in tumor-associated epilepsy regardless of location (class I: 80%). A surgical complication occurred in 8% after resective surgery - with only 2.5% permanent morbidity - and 4.3% after invasive monitoring (mostly hemorrhagic). Overall results obtained by epilepsy surgery centers were in the higher range of those reported in the literature, along with a low rate of major surgical complications. Growing interest for epilepsy surgery is clearly demonstrated in this survey and supports further development to better satisfy the population's needs, particularly children. Activity should be further evaluated, while existing epilepsy surgery centers as well as healthcare networks should be expanded.
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Epilepsia/cirurgia , Procedimentos Neurocirúrgicos/estatística & dados numéricos , Adulto , Encéfalo/patologia , Criança , Eletroencefalografia , Epilepsia/epidemiologia , Epilepsia/patologia , França/epidemiologia , Pesquisas sobre Atenção à Saúde , Humanos , Monitorização Intraoperatória , Procedimentos Neurocirúrgicos/efeitos adversos , Complicações Pós-Operatórias/epidemiologia , Inquéritos e Questionários , Resultado do TratamentoRESUMO
INTRODUCTION: Malignant primary diffuse leptomeningeal gliomatosis (MPDLG) are rare central nervous system neoplasms associated with a poor outcome. CASE REPORT: We report the case of a 40-year-old woman who presented with unusual worsening of bilateral sciatica, headaches, diplopia and a left proptosis. MRI of the head and spine showed multiple leptomeningeal lesions with no intra parenchymal involvement. The search for a primary tumor was negative. An open surgical biopsy of the prominent intradural lumbar tumor was performed within a week. Histopathology, immunochemistry and molecular analyses revealed a malignant glioma with histone H3.3 K27M mutation. The patient was referred to the neuro-oncologist for chemotherapy and craniospinal radiotherapy. Despite aggressive therapy, she died of disseminated tumoral progression, 18 weeks after the diagnosis. CONCLUSION: MPLG is a rare tumor which should be considered whenever a patient presents with diffuse or multinodular meningeal contrast-enhancing lesions. Some cases of MLPG share histological and immunophenotypical features with diffuse midline gliomas H3-K27M-mutant, a rapidly fatal disease. The diagnosis remains histopathological and, therefore a biopsy is obligatory without delay. Immunohistochemistry and/or molecular analyses are now currently essential for a formal classification and, to provide a better prediction of clinical outcome, particularly in this heterogeneous group of tumors.
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Glioma/genética , Histonas/genética , Neoplasias Meníngeas/genética , Neoplasias Meníngeas/patologia , Mutação/genética , Neoplasias Neuroepiteliomatosas/genética , Neoplasias Neuroepiteliomatosas/patologia , Adulto , Biópsia , Feminino , Glioma/diagnóstico , Humanos , Neoplasias Meníngeas/diagnóstico , Neoplasias Neuroepiteliomatosas/diagnósticoRESUMO
BACKGROUND: To report on the outcome of patients diagnosed with central nervous system haemangiopericytoma (HPC) or solitary fibrous tumours (SFT) and identify factors that may influence recurrence and survival. MATERIAL AND METHODS: Between January 1977 and December 2016, a retrospective search identified 22 HPCs/SFTs. The patients underwent a total of 40 surgical resections and 63.6% received radiotherapy. Median follow-up was 7.8 years. RESULTS: Six patients (27.3%) were re-operated for tumour recurrence. At the end of the study, 15 patients (68.2%) had no residual tumour on the last imaging. Surgical recurrence-free survival at 5 years was 77.4%, [95% CI: 60.1-99.8]. None of the investigated variables was associated with recurrence. At the end of the study, 5 patients were deceased (22.7%) and only 10 patients (45.5%) had no residual tumour on the last imaging and were alive. Overall survival at 5 years was 95%, [95% CI: 85.9-100]. None of the investigated variables was associated with overall survival. Patients who received radiotherapy demonstrated neither a reduced risk of surgical recurrence (P=0.378) nor a longer overall survival (P=0.405). CONCLUSION: SFTs/HPCs are associated with a significant risk of recurrence that may reduce the survival. Even if we could not demonstrate their benefit in this limited series, we believe that tailored maximal tumour resection on initial surgery is beneficial and that adjuvant RT is useful for tumours displaying grade II or III, even in case of complete removal.
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Neoplasias do Sistema Nervoso Central/terapia , Hemangiopericitoma/terapia , Neoplasias Meníngeas/terapia , Tumores Fibrosos Solitários/terapia , Adulto , Idoso , Neoplasias do Sistema Nervoso Central/mortalidade , Neoplasias do Sistema Nervoso Central/radioterapia , Neoplasias do Sistema Nervoso Central/cirurgia , Feminino , Hemangiopericitoma/mortalidade , Hemangiopericitoma/radioterapia , Hemangiopericitoma/cirurgia , Humanos , Masculino , Neoplasias Meníngeas/mortalidade , Neoplasias Meníngeas/radioterapia , Neoplasias Meníngeas/cirurgia , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Prognóstico , Estudos Retrospectivos , Tumores Fibrosos Solitários/mortalidade , Tumores Fibrosos Solitários/radioterapia , Tumores Fibrosos Solitários/cirurgia , Análise de Sobrevida , Resultado do Tratamento , Adulto JovemRESUMO
Accurate intraoperative tumour margin assessment is a major challenge in neurooncology, where sparse tumours beyond the bulk tumour are left undetected under conventional resection. Non-linear optical imaging can diagnose tissue at the sub-micron level and provide functional label-free histopathology in vivo. For this reason, a non-linear endomicroscope is being developed to characterize brain tissue intraoperatively based on multiple endogenous optical contrasts such as spectrally- and temporally-resolved fluorescence. To produce highly sensitive optical signatures that are specific to a given tissue type, short femtosecond pulsed lasers are required for efficient two-photon excitation. Yet, the potential of causing bio-damage has not been studied on neuronal tissue. Therefore, as a prerequisite to clinically testing the non-linear endomicroscope in vivo, the effect of short laser pulse durations (40-340 fs) on ex vivo brain tissue was investigated by monitoring the intensity, the spectral, and the lifetime properties of endogenous fluorophores under 800 and 890 nm two-photon excitation using a bi-modal non-linear endoscope. These properties were also validated by imaging samples on a benchtop multiphoton microscope. Our results show that under a constant mean laser power, excitation pulses as short as 40 fs do not negatively alter the biochemical/ biophysical properties of tissue even for prolonged irradiation.
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Encéfalo/diagnóstico por imagem , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Neoplasias/diagnóstico por imagem , Imagem Óptica/métodos , Encéfalo/patologia , Encéfalo/cirurgia , Corantes Fluorescentes/farmacologia , Frequência Cardíaca , Humanos , Lasers , Margens de Excisão , Neoplasias/patologia , Neoplasias/cirurgia , Neurônios/fisiologia , FótonsRESUMO
We used DNase I footprinting assays on nuclei isolated from adenovirus-infected cells to examine the nucleoprotein configuration of a 250-base-pair segment which encompasses the adenovirus type 5 major late (ML) and IVa2 promoters. At 12 and 20 h postinfection (p.i.), fine DNase I digestion mapping of wild-type adenovirus-infected cells revealed specific sequences protected from digestion which corresponded to promoter elements required for expression of the ML gene in vivo. At 12 h p.i., a G+C-rich region which lies upstream of the IVa2 cap site and is important for maximal IVa2 activity was also found masked to nuclease activity. At 20 h p.i., however, this element became more sensitive to nuclease attack, while the ML promoter elements stayed protected. No major changes in DNA-protein interactions were detected in the region spanning the ML and IVa2 cap sites upon promoter activation, suggesting that the binding properties of the cognate factors for this region are not modified during the process.
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Adenovírus Humanos/genética , Transformação Celular Viral , Proteínas de Ligação a DNA/genética , Regiões Promotoras Genéticas , Fatores de Transcrição/genética , Proteínas Virais/genética , Sequência de Bases , Núcleo Celular/metabolismo , Genes , Genes Virais , Células HeLa/metabolismo , Humanos , Dados de Sequência MolecularRESUMO
Specific protein binding on the EIa-inducible adenovirus EIIa early (EIIaE) promoter was analyzed by the sensitive electrophoretic band-shift assay and by protection against DNase I digestion. Three factors were identified, and precise mapping of the cognate-binding sites revealed their correspondence to promoter elements essential for constitutive EIIaE transcription. One binds to the major upstream element located between -82 and -64 (with respect to the major EIIaE cap site), another appears to interact with sequences on either side of this region, and the last one binds to an element located further upstream. Comparison of the binding activities of the factors present in extracts from cells infected with wild-type adenovirus (adenovirus type 5) or with the EIa deletion mutant dl312 did not reveal striking differences. Not only were the general binding patterns indistinguishable, but the concentration of each of the identified factors as well as their affinity for the cognate-binding sites were unchanged. Our results suggest that the EIa-mediated activation of the EIIaE transcription complexes involves appropriate interactions between transcription factors, rather than their increased binding to DNA.
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DNA Viral/metabolismo , Proteínas de Ligação a DNA/fisiologia , Proteínas Oncogênicas Virais/genética , Regiões Promotoras Genéticas , Transcrição Gênica , Proteínas Precoces de Adenovirus , Sequência de Bases , Sítios de Ligação , Análise Mutacional de DNA , Regulação da Expressão Gênica , Células HeLa , Técnicas In Vitro , Dados de Sequência Molecular , Nucleoproteínas/metabolismo , Ligação ProteicaRESUMO
Genomic DNase I footprinting was used to compare specific protein binding to the adenovirus type 5 early, EIa-inducible, EIIa promoter. Identical protection patterns of the promoter region were observed whether EIIa transcription was undetectable or fully induced. These results suggest that EIa-mediated transcriptional induction does not increase binding of limiting transcription factors to the promoter but rather that transactivation results from the proper interactions between factors already bound to their cognate sequences.