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1.
Childs Nerv Syst ; 35(10): 1809-1826, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31352576

RESUMO

PURPOSE: Despite decades of experience and research, the etiology and management of Chiari I malformations (CM-I) continue to raise more questions than answers. Controversy abounds in every aspect of management, including the indications, timing, and type of surgery, as well as clinical and radiographic outcomes. This review aims to outline past experiences, consolidate current evidence, and recommend directions for the future management of the Chiari I malformation. METHODS: A review of recent literature on the management of CM-I in pediatric patients is presented, along with our experience in managing 1073 patients who were diagnosed with CM-I over the past two decades (1998-2018) at Children's National Medical Center (CNMC) in Washington DC. RESULTS: The general trend reveals an increase in the diagnosis of CM-I at younger ages with a significant proportion of these being incidental findings (0.5-3.6%) in asymptomatic patients as well as a rise in the number of patients undergoing Chiari posterior fossa decompression surgery (PFD). The type of surgical intervention varies widely. At our institution, 104 (37%) Chiari surgeries were bone-only PFD with/without outer leaf durectomy, whereas 177 (63%) were PFD with duraplasty. We did not find a significant difference in outcomes between the PFD and PFDD groups (p = 0.59). An analysis of failures revealed a significant difference between patients who underwent tonsillar coagulation versus those whose tonsils were not manipulated (p = 0.02). CONCLUSION: While the optimal surgical intervention continues to remain elusive, there is a shift away from intradural techniques in favor of a simple, extradural approach (including dural delamination) in pediatric patients due to high rates of clinical and radiographic success, along with a lower complication rate. The efficacy, safety, and necessity of tonsillar manipulation continue to be heavily contested, as evidence increasingly supports the efficacy and safety of less tonsillar manipulation, including our own experience.


Assuntos
Malformação de Arnold-Chiari/diagnóstico por imagem , Malformação de Arnold-Chiari/cirurgia , Gerenciamento Clínico , Siringomielia/diagnóstico por imagem , Siringomielia/cirurgia , Descompressão Cirúrgica/métodos , Descompressão Cirúrgica/tendências , Humanos , Laminectomia/métodos , Laminectomia/tendências , Imageamento por Ressonância Magnética/métodos , Imageamento por Ressonância Magnética/tendências
2.
Int J Pediatr Otorhinolaryngol ; 100: 141-144, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28802360

RESUMO

OBJECTIVE: The purpose of this study is to highlight the relationship between obstructive hydrocephalus, changes in intracranial pressure, and sensorineural hearing loss. METHODS: A case of a 10-month old infant with sensorineural hearing loss secondary to obstructive hydrocephalus is reported. A literature review, with a focus on sensorineural hearing loss in the setting of changes in intracranial pressure, was performed. RESULTS: The authors report the case of a 10-month old infant with metopic and bicoronal craniosynostosis who presented with bilateral moderately severe sensorineural hearing loss after failing newborn hearing screening. Imaging subsequently demonstrated obstructive hydrocephalus, which was treated with the insertion of a VP shunt. The patient had immediate improvement of her hearing post-operatively, with repeat hearing tests showed resolution of her hearing loss. CONCLUSION: Sensorineural hearing loss is a rare complication of hydrocephalus, but changes in intracranial pressure should be considered in the differential diagnosis. We put forth a flow diagram illustrating the hypothesized relationship between intracranial pressures, alterations in the levels of cochlear fluid, and hearing.


Assuntos
Craniossinostoses/cirurgia , Perda Auditiva Bilateral/cirurgia , Perda Auditiva Neurossensorial/cirurgia , Hidrocefalia/cirurgia , Derivação Ventriculoperitoneal/métodos , Cóclea/fisiopatologia , Craniossinostoses/complicações , Feminino , Perda Auditiva Bilateral/etiologia , Perda Auditiva Neurossensorial/etiologia , Testes Auditivos , Humanos , Hidrocefalia/complicações , Lactente , Imageamento por Ressonância Magnética , Próteses e Implantes/efeitos adversos , Resultado do Tratamento
3.
Neuroscience ; 148(2): 359-70, 2007 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-17681695

RESUMO

Traumatic brain injury (TBI) causes selective hippocampal cell death which is believed to be associated with the cognitive impairment observed in both clinical and experimental settings. The endogenous neurotrophin-4/5 (NT-4/5), a TrkB ligand, has been shown to be neuroprotective for vulnerable CA3 pyramidal neurons after experimental brain injury. In this study, infusion of recombinant NT-4/5 increased survival of CA2/3 pyramidal neurons to 71% after lateral fluid percussion brain injury in rats, compared with 55% in vehicle-treated controls. The functional outcome of this NT-4/5-mediated neuroprotection was examined using three hippocampal-dependent behavioral tests. Injury-induced impairment was evident in all three tests, but interestingly, there was no treatment-related improvement in any of these measures. Similarly, injury-induced decreased excitability in the Schaffer collaterals was not affected by NT-4/5 treatment. We propose that a deeper understanding of the factors that link neuronal survival to recovery of function will be important for future studies of potentially therapeutic agents.


Assuntos
Lesões Encefálicas/tratamento farmacológico , Hipocampo/patologia , Fatores de Crescimento Neural/uso terapêutico , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/uso terapêutico , Animais , Aprendizagem por Associação/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Lesões Encefálicas/patologia , Contagem de Células/métodos , Modelos Animais de Doenças , Relação Dose-Resposta à Radiação , Estimulação Elétrica/métodos , Potenciais Evocados/efeitos dos fármacos , Potenciais Evocados/efeitos da radiação , Hipocampo/fisiopatologia , Técnicas In Vitro , Masculino , Atividade Motora/efeitos dos fármacos , Neurônios/fisiologia , Ratos , Ratos Sprague-Dawley , Recuperação de Função Fisiológica/efeitos dos fármacos , Recuperação de Função Fisiológica/fisiologia , Fatores de Tempo
4.
Biochem Biophys Res Commun ; 290(1): 230-5, 2002 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-11779158

RESUMO

Peroxisome proliferator-activated receptors (alpha, delta and gamma) are ligand-activated transcription factors that are involved in multiple cellular responses. The PPARdelta subtype is the least understood of all PPAR subtypes. PPARdelta is activated by unsaturated fatty acids, PGI2, and by synthetic ligands. PPARdelta-regulated genes have not been identified and the factors that control PPARdelta expression are not known. The gene that encodes the mouse PPARdelta gene is contained in >30 kb DNA sequence and organized in eight exons, six of which encode the PPARdelta receptor. A PPARdelta-luciferase reporter containing 694 bp 5' upstream regulatory and 127 bp untranslated was introduced to primary brain cultures to begin a characterization of the DNA sequences that mediate transcriptional regulation of PPARdelta. PPARdelta-luciferase expression was 10 times higher in oligodendrocyte-containing mature cultures than in immature cultures, indicating that PPARdelta may play a role during oligodendrocyte migration, proliferation, and/or maturation.


Assuntos
Receptores Citoplasmáticos e Nucleares/química , Receptores Citoplasmáticos e Nucleares/genética , Fatores de Transcrição/química , Fatores de Transcrição/genética , Regiões 5' não Traduzidas , Animais , Animais Recém-Nascidos , Sequência de Bases , Encéfalo/metabolismo , Divisão Celular , Células Cultivadas , Éxons , Íntrons , Ligantes , Luciferases/metabolismo , Camundongos , Dados de Sequência Molecular , Fenótipo , Estrutura Terciária de Proteína , Ratos , Transcrição Gênica , Transfecção
5.
Neurosurgery ; 49(4): 1014-6; conclusion 1016-7, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11564268

RESUMO

OBJECTIVE AND IMPORTANCE: Craniopharyngiomas, epithelial tumors of the hypothalamic and pituitary region, are thought to have congenital origins. It has been postulated that hormonal influences may stimulate growth in adults. This report describes a case and reviews the literature. CLINICAL PRESENTATION: The case is discussed of a 39-year-old woman who experienced symptoms from a craniopharyngioma diagnosed during a pregnancy that resulted from in vitro fertilization. A magnetic resonance imaging scan performed 4 years previously had disclosed nothing abnormal. INTERVENTION: The patient underwent a right frontotemporal craniotomy with total resection of the suprasellar tumor, which was dissected from the pituitary stalk. CONCLUSION: This case suggests a possible link in the adult patient between the growth of this supposedly congenital tumor and hormonal stimulation.


Assuntos
Craniofaringioma/diagnóstico , Imageamento por Ressonância Magnética , Neoplasias Hipofisárias/diagnóstico , Complicações Neoplásicas na Gravidez/diagnóstico , Adulto , Encéfalo/patologia , Craniofaringioma/patologia , Craniofaringioma/cirurgia , Craniotomia , Feminino , Seguimentos , Humanos , Neoplasias Hipofisárias/patologia , Neoplasias Hipofisárias/cirurgia , Gravidez , Complicações Neoplásicas na Gravidez/patologia , Complicações Neoplásicas na Gravidez/cirurgia
7.
Proc Natl Acad Sci U S A ; 94(9): 4681-5, 1997 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-9114051

RESUMO

The cytosine analog 5-aza-2'-deoxycytidine has been used clinically to reactivate genes silenced by DNA methylation. In particular, patients with beta-thalassemia show fetal globin expression after administration of this hypomethylating drug. In addition, silencing of tumor suppressor gene expression by aberrant DNA methylation in tumor cells may potentially be reversed by a similar regimen. Consistent with its function in maintaining tumor suppressor gene expression, 5-aza-2'-deoxycytidine significantly reduces intestinal tumor multiplicity in the predisposed Min mouse strain. Despite its utility as an anti-cancer agent, the drug is highly mutagenic by an unknown mechanism. To gain insight into how 5-aza-2'-deoxycytidine induces mutations in vivo, we examined the mutational spectrum in an Escherichia coli lac I transgene in colonic DNA from 5-aza-2'-deoxycytidine-treated mice. Mutations induced by 5-aza-2'-deoxycytidine were predominantly at CpG dinucleotides, which implicates DNA methyltransferase in the mutagenic mechanism. C:G-->G:C transversions were the predominant class of mutations observed. We suggest a model for how the mammalian DNA methyltransferase may be involved in facilitating these mutations. The observation that 5-aza-2'-deoxycytidine-induced mutations are mediated by the enzyme suggests that novel inhibitors of DNA methyltransferase, which can inactivate the enzyme before its interaction with DNA, are needed for chemoprevention or long term therapy.


Assuntos
Antimetabólitos Antineoplásicos/farmacologia , Azacitidina/análogos & derivados , Metilação de DNA , Metiltransferases/metabolismo , Mutagênicos/farmacologia , Animais , Azacitidina/farmacologia , Decitabina , Fosfatos de Dinucleosídeos/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Modelos Químicos , Modelos Genéticos , Mutagênese
9.
J Craniofac Surg ; 7(4): 267-70, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9133829

RESUMO

Sixty-seven surgeons, members of the International Craniofacial Surgery Society, responded to a questionnaire focused on assessing the incidence and risk of cranial plate and screw translocation intracranially in infants undergoing cranial surgery. Despite screws, plates, and wires being evident intracranially in individual cases, no apparent increase in seizure frequency or susceptibility to head trauma was noted in this preliminary study.


Assuntos
Placas Ósseas/efeitos adversos , Parafusos Ósseos/efeitos adversos , Lesões Encefálicas/etiologia , Migração de Corpo Estranho/complicações , Craniotomia/efeitos adversos , Humanos , Lactente , Meninges/lesões , Reoperação , Estudos Retrospectivos , Medição de Risco , Convulsões/etiologia , Inquéritos e Questionários
10.
Glia ; 15(2): 195-202, 1995 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8567071

RESUMO

Fluorescence Recovery After Photobleach (FRAP) was used to quantify astrocyte gap junction coupling from tissues surgically resected from medically intractable epilepsy patients. Mesial temporal lobe cases provided hippocampus, surrounding hyperexcitable parahippocampus and normal cortex for culture. Cortical tumor cases yielded astrocytoma proper, cortex margins with normal EEG activity, and hyperexcitable cortex. Cells isolated from cortex surrounding astrocytomas and the parahippocampus surrounding the hippocampus showed an increase in glutamate-induced Ca2+ oscillations and intercellular Ca2+ waves. Gap-junction coupling was more pronounced in cells isolated from hyperexcitable tissue than from normal tissues as judged by their faster and more complete fluorescence recovery from laser bleach [FRAP]. This data suggests that intractable epilepsy may be associated with alterations in glial gap junction coupling.


Assuntos
Astrócitos/fisiologia , Epilepsia/fisiopatologia , Junções Comunicantes/fisiologia , Astrócitos/efeitos dos fármacos , Astrócitos/ultraestrutura , Astrocitoma/fisiopatologia , Astrocitoma/ultraestrutura , Neoplasias Encefálicas/fisiopatologia , Neoplasias Encefálicas/ultraestrutura , Cálcio/metabolismo , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/fisiopatologia , Córtex Cerebral/ultraestrutura , Técnicas de Cultura , Eletroencefalografia , Junções Comunicantes/efeitos dos fármacos , Junções Comunicantes/ultraestrutura , Ácido Glutâmico/fisiologia , Humanos , Imageamento por Ressonância Magnética , Microscopia de Fluorescência , Lobo Temporal/efeitos dos fármacos , Lobo Temporal/fisiopatologia , Lobo Temporal/ultraestrutura
11.
Mol Endocrinol ; 6(5): 815-25, 1992 May.
Artigo em Inglês | MEDLINE | ID: mdl-1603088

RESUMO

The thyroid hormone receptor (TR) has the dual ability to activate or repress transcription of specific genes. A cell-free transcription system was used to study the effects of TR on transcription by positively (TREpMLP) and negatively (TSH alpha) regulated promoters. Receptor-deficient HeLa cell extracts were complemented with baculovirus-produced TR. TR stimulated transcription from the TREpMLP promoter by 3-fold, and trans-activation did not require hormone. Transcriptional stimulation by TR required the presence of the TRE sequence and was diminished by the addition of competitor TRE binding sites. Baculovirus-produced TR repressed transcription in vitro from the TSH alpha promoter by 30-50%, also in a hormone-independent manner. Transcription from a control adenovirus 2 major late promoter was unaffected by added TR. Receptor-specific antisera and competition with TRE binding sites impaired TR-mediated repression of the TSH alpha promoter. Unlike transcriptional stimulation, which was optimal when TR and HeLa extracts were added concomitantly, transcriptional repression by the TR was most effective when the receptor was preincubated with the alpha-promoter, suggesting that receptor binding to the promoter may block access of other proteins to cause transcriptional repression. These results indicate that baculovirus-expressed TR mediates transcriptional activation and repression in a promoter-specific manner in vitro. This system provides a valuable model for examining transcriptional control by the TR.


Assuntos
Receptores dos Hormônios Tireóideos/fisiologia , Transcrição Gênica/fisiologia , Baculoviridae , Sequência de Bases , Sistema Livre de Células , Regulação da Expressão Gênica , Humanos , Dados de Sequência Molecular , Regiões Promotoras Genéticas , Proteínas Recombinantes , Sequências Reguladoras de Ácido Nucleico , Proteínas Repressoras/fisiologia , Ativação Transcricional
12.
Arthritis Rheum ; 31(8): 937-46, 1988 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-2841944

RESUMO

Studies by light microscopy on synovium obtained from 11 patients with Reiter's syndrome during the first month of an episode showed proliferation of synovial lining cells, polymorphonuclear neutrophils among the synovial lining cells, increased surface fibrin, and vascular congestion. Biopsy specimens taken later showed vascular congestion and still proliferated synovial lining cells, fewer polymorphonuclear neutrophils in some, and a tendency toward increased infiltration with lymphocytes and plasma cells. Electron microscopy of samples from 8 patients during the first month of disease activity showed occlusion of vessels by platelets in 4, and fibrin or dense granular material in the vessel walls in 4. Five of the patients with arthritis of less than 4 weeks duration had unidentified intracellular and extracellular particles; some of these were highly suggestive of Chlamydia. No such particles were noted in samples from patients with more chronic cases. Using an antibody to Chlamydia trachomatis and the peroxidase-antiperoxidase technique, immunocytochemistry showed reaction product in synovial macrophages in 2 patients with arthritis of less than 4 weeks duration, but not in the 1 patient studied who had more chronic disease. These studies provide support for dramatic synovial vascular injury consistent with that caused by endotoxin and the presence of chlamydial antigen in synovial macrophages, at least in the early phases of synovitis.


Assuntos
Antígenos de Bactérias/análise , Artrite Reativa/patologia , Infecções por Chlamydia/imunologia , Chlamydia trachomatis/imunologia , Membrana Sinovial/patologia , Adulto , Artrite Reativa/etiologia , Biópsia , Humanos , Técnicas Imunoenzimáticas , Corpos de Inclusão/ultraestrutura , Macrófagos/imunologia , Microscopia Eletrônica , Neutrófilos/patologia
13.
Biochem Biophys Res Commun ; 154(3): 1081-7, 1988 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-3044365

RESUMO

Livers of insulin-treated diabetic rats accumulate albumin and malic enzyme mRNAs at very different rates. We now report that in normal rats insulin directs a specific increase in malic enzyme mRNA, while albumin mRNA levels remain unaltered. These studies support the contention that insulin regulates the accumulation of hepatic mRNAs in a highly specific manner. To evaluate whether or not albumin and malic enzyme mRNA levels are determined by altered rates of transcription, in vitro transcription assays were performed. The results of these studies demonstrate that increased malic enzyme mRNA levels in insulin-treated normal rats and increased malic enzyme and albumin mRNA levels in insulin-treated diabetic rats do not involve altered rates of transcription of the genetic sequences encoding these proteins. For these two specific proteins, insulin mediates changes in mRNA levels by a post-transcriptional mechanism.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Insulina/farmacologia , Fígado/metabolismo , Malato Desidrogenase/genética , Processamento Pós-Transcricional do RNA/efeitos dos fármacos , RNA Mensageiro/genética , Albumina Sérica/genética , Animais , Núcleo Celular/metabolismo , Fígado/efeitos dos fármacos , Masculino , Hibridização de Ácido Nucleico , RNA Mensageiro/efeitos dos fármacos , Ratos , Ratos Endogâmicos , Valores de Referência , Transcrição Gênica/efeitos dos fármacos
14.
Arthritis Rheum ; 31(7): 914-7, 1988 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-3395384

RESUMO

A 48-year-old man with "rheumatoid arthritis" of 3 years duration was found to have synovial fluid lymphocytes that were maximally stimulated in vitro by chlamydial antigen, on 5 of 6 tests over 18 months. Immunocytochemical staining of a synovectomy specimen, using the peroxidase-antiperoxidase technique, subsequently revealed chlamydial antigen in the synovium. The possibility that Chlamydia in the synovium may produce features of rheumatoid arthritis is discussed.


Assuntos
Antígenos Virais/fisiologia , Artrite Reativa/patologia , Chlamydia/imunologia , Ativação Linfocitária , Linfócitos/fisiologia , Líquido Sinovial/citologia , Adolescente , Antígenos Virais/análise , Artrite Reativa/imunologia , Humanos , Masculino , Microscopia Eletrônica , Membrana Sinovial/imunologia , Membrana Sinovial/patologia , Membrana Sinovial/ultraestrutura
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