The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Andrew J Copp - One of the best experts on this subject based on the ideXlab platform.
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novel mouse model of Encephalocele post neurulation origin and relationship to open neural tube defects
Disease Models & Mechanisms, 2019Co-Authors: Ana Rolo, Gabriel L Galea, Dawn Savery, Nicholas D E Greene, Andrew J CoppAbstract:ABSTRACT Encephalocele is a clinically important birth defect that can lead to severe disability in childhood and beyond. The embryonic and early fetal pathogenesis of Encephalocele is poorly understood and, although usually classified as a ‘neural tube defect’, there is conflicting evidence on whether Encephalocele results from defective neural tube closure or is a post-neurulation defect. It is also unclear whether Encephalocele can result from the same causative factors as anencephaly and open spina bifida, or whether it is aetiologically distinct. This lack of information results largely from the scarce availability of animal models of Encephalocele, particularly ones that resemble the commonest, nonsyndromic human defects. Here, we report a novel mouse model of occipito-parietal Encephalocele, in which the small GTPase Rac1 is conditionally ablated in the (non-neural) surface ectoderm. Most mutant fetuses have open spina bifida, and some also exhibit exencephaly/anencephaly. However, a proportion of mutant fetuses exhibit brain herniation, affecting the occipito-parietal region and closely resembling Encephalocele. The Encephalocele phenotype does not result from defective neural tube closure, but rather from a later disruption of the surface ectoderm covering the already closed neural tube, allowing the brain to herniate. The neuroepithelium itself shows no downregulation of Rac1 and appears morphologically normal until late gestation. A large skull defect overlies the region of brain herniation. Our work provides a new genetic model of occipito-parietal Encephalocele, particularly resembling nonsyndromic human cases. Although Encephalocele has a different, later-arising pathogenesis than open neural tube defects, both can share the same genetic causation.
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novel mouse model of Encephalocele post neurulation origin and relationship to open neural tube defects
bioRxiv, 2019Co-Authors: Ana Rolo, Gabriel L Galea, Dawn Savery, Nicholas D E Greene, Andrew J CoppAbstract:ABSTRACT Encephalocele is a clinically important birth defect that can lead to severe disability in childhood and beyond. The embryonic pathogenesis of Encephalocele is poorly understood and, while usually classified as a ‘neural tube defect’, there is conflicting evidence on whether Encephalocele results from defective neural tube closure, or is a post-neurulation defect. It is also unclear whether Encephalocele can result from the same causative factors as anencephaly and open spina bifida, or whether it is aetiologically distinct. This lack of information results largely from the scarce availability of animal models of Encephalocele, particularly ones that resemble the commonest, non-syndromic human defects. Here we report a novel mouse model of occipito-parietal Encephalocele, in which the small GTPase Rac1 is conditionally ablated in the (non-neural) surface ectoderm. Most mutant fetuses have open spina bifida, and some also exhibit exencephaly/anencephaly. However, a large proportion of mutant fetuses exhibit Encephalocele affecting the occipito-parietal region. The Encephalocele phenotype does not result from a defect in neural tube closure, but rather from a later disruption of the surface ectoderm covering the already closed neural tube, allowing the brain to herniate. The neuroepithelium itself shows no down-regulation of Rac1 and appears morphologically normal until late gestation. A large skull defect develops overlying the region of brain herniation. Our work provides a new genetic model of occipito-parietal Encephalocele, particularly resembling non-syndromic human cases. While Encephalocele has a different, later-arising pathogenesis than open neural tube defects, both can share the same genetic causation. SUMMARY STATEMENT Encephalocele - a severe brain defect - arises after neural tube closure, but can share a common genetic cause with anencephaly, a defect of neural tube closure.
John S Archer - One of the best experts on this subject based on the ideXlab platform.
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small temporal pole Encephaloceles a treatable cause of lesion negative temporal lobe epilepsy
Epilepsia, 2010Co-Authors: Amal Abouhamden, Gavin Fabinyi, Samuel F Berkovic, Graeme D Jackson, Anne L Mitchell, Renate M Kalnins, Gregory J Fitt, John S ArcherAbstract:Summary Epilepsy due to Encephaloceles of the temporal pole may be an under recognized, treatable cause of refractory temporal lobe epilepsy (TLE). We describe three adult patients initially labeled “lesion negative” TLE. In all, video–electroencephalography (EEG) revealed ictal theta in the left temporal region and positron emission tomography (PET) showed temporal lobe hypometabolism, but neuropsychology revealed preserved verbal memory. Close inspection of structural magnetic resonance imaging (MRI) suggested subtle abnormalities at the tip of the left temporal lobe. High resolution computed tomography (CT) confirmed bony defects in the inner table of the skull. 3T MRI with fine coronal and sagittal slices indicated cerebrospinal fluid (CSF) and brain tissue protruding into the defects. All proceeded to resection of the temporal tip and became seizure free. Patients with “lesion negative” TLE should have careful review of images covering the temporal pole. If Encephalocele is suspected, further imaging with high-resolution CT and MRI can be helpful. Temporal polar resection, sparing mesial structures, appears to be curative.
George B Wanna - One of the best experts on this subject based on the ideXlab platform.
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temporal bone Encephalocele and cerebrospinal fluid fistula repair utilizing the middle cranial fossa or combined mastoid middle cranial fossa approach
Journal of Neurosurgery, 2013Co-Authors: Matthew L Carlson, William R Copeland, Colin L W Driscoll, Michael J Link, David S Haynes, Reid C Thompson, Kyle D Weaver, George B WannaAbstract:Object The goals of this study were to report the clinical presentation, radiographic findings, operative strategy, and outcomes among patients with temporal bone Encephaloceles and cerebrospinal fluid fistulas (CSFFs) and to identify clinical variables associated with surgical outcome. Methods A retrospective case series including all patients who underwent a middle fossa craniotomy or combined mastoid–middle cranial fossa repair of Encephalocele and/or CSFF between 2000 and 2012 was accrued from 2 tertiary academic referral centers. Results Eighty-nine consecutive surgeries (86 patients, 59.3% women) were included. The mean age at time of surgery was 52.3 years, and the left side was affected in 53.9% of cases. The mean delay between symptom onset and diagnosis was 35.4 months, and the most common presenting symptoms were hearing loss (92.1%) and persistent ipsilateral otorrhea (73.0%). Few reported a history of intracranial infection (6.7%) or seizures (2.2%). Thirteen (14.6%) of 89 cases had a history...
Gerald B Healy - One of the best experts on this subject based on the ideXlab platform.
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nasal glioma and Encephalocele diagnosis and management
Laryngoscope, 2003Co-Authors: Reza Rahbar, Vicente A Resto, Caroline D Robson, Antonio R Perezatayde, Liliana Goumnerova, Trevor J Mcgill, Gerald B HealyAbstract:Objective: To review the biology of nasal glioma and Encephalocele and to present an algorithm for preoperative evaluation and surgical management. Design: Retrospective review and analysis. Setting: Tertiary care medical center: 1970 to 2002. Patient: Sixteen patients with glioma (n = 10) and Encephalocele (n = 6). Outcome: Age at the time of presentation, sex, signs and symptoms, imaging findings, surgical approach, pathology, complications, rate of recurrence, and follow-up were recorded. Results: Ten patients presented with nasal glioma with a mean age of 9 months. All patients underwent surgical excision. No complication was encountered with a mean follow-up of 3.5 years. Six patients presented with Encephaloceles with a mean age of 15.5 months. All patients underwent surgical excision. Complications included cerebrospinal fluid leak (n = 1) and epiphora (n = 1). Follow-up was 1 to 14 years (mean, 4 years). Conclusion: Nasal glioma and Encephalocele are rare, benign, congenital lesions with a potential for intracranial extension. Evaluation should include a complete rhinologic and neurologic examination. Preoperative imaging with a thin-cut axial and coronal computed tomography scan andlor multiplanar magnetic resonance imaging is essential. Surgical intervention should be performed soon after diagnosis to alleviate the increased risk of meningitis. A frontal craniotomy approach is recommended if intracranial extension is identified based on preoperative evaluation, followed by an extracranial resection. If there is no evidence of intracranial extension, a conservative extracranial approach is recommended.
Alan Sherwin - One of the best experts on this subject based on the ideXlab platform.
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developmental anterobasal temporal Encephalocele and temporal lobe epilepsy
Journal of Neurosurgery, 1991Co-Authors: Richard Leblanc, Donatella Tampieri, Yves Robitaille, Andre Olivier, Frederick Andermann, Alan SherwinAbstract:✓ The authors describe the association between an anterobasal temporal lobe Encephalocele and medically intractable temporal lobe epilepsy in three patients treated successfully by surgery. Two men and one woman, aged 26 to 37 years (mean 31 years), had onset of complex automatism and generalized seizures in their second and fourth decades (mean age 22.7 years). They had been epileptic for 6 to 14 years (mean 8.3 years) before surgery. Preoperative electroencephalograms localized ictal epileptic activity to the left mesial temporal lobe in all cases, and neuropsychological testing revealed dominant temporal lobe dysfunction. Magnetic resonance (MR) imaging demonstrated an anteromedial basal temporal Encephalocele extending into the pterygopalatine fossa through a bone defect at the base of the greater sphenoid wing in the region of the foramen rotundum and pterygoid process, a discrete center of embryonal chondrification. At surgery, the Encephaloceles were found in front of the uncus, and an area of glio...