Publications by authors named "Harvey Sarnat"

Background: Primary small vessel CNS vasculitis (sv-cPACNS) is a challenging inflammatory brain disease in children. Brain biopsy is mandatory to confirm the diagnosis. This study aims to develop and validate a histological scoring tool for diagnosing small vessel CNS vasculitis.

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Keratan sulfate (KS) is a proteoglycan secreted in the fetal brain astrocytes and radial glia into extracellular parenchyma as granulofilamentous deposits. KS surrounds neurons except dendritic spines, repelling glutamatergic and facilitating GABAergic axons. The same genes are expressed in both neuroblast migration and axonal growth.

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Insight into neuroembryology, developmental neuroanatomy and neurophysiology distinguish the diagnostic approaches of paediatric from adult neurologists and general paediatricians. These fundamental disciplines of basic neuroscience could be more effectively taught during paediatric neurology and most residency programmes, that will strengthen career-long learning. Interdisciplinary training of fetal-neonatal neurology within these programs requires working knowledge of neuroembryology applied to maternal reproductive health influencing the maternal-placental-fetal triad, neonate, and young child.

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Peripheral neuroblastic tumors of childhood exhibit 3 principal neural crest lineages: primitive neuroblastoma, ganglioneuroblastoma, and ganglioneuroma. They are unique in undergoing maturation of neurons (ganglion cells) and Schwann cells, thereby recapitulating normal fetal neuronal development in the brain. Precision in estimating neurogenesis is enhanced by immunoreactivities of markers of neuronal maturation.

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Children with tuberous sclerosis complex (TSC), may experience a variety of seizure types in the first year of life, most often focal seizure sand epileptic spasms. Drug resistance is seen early in many patients, and the management of TSC associated epilepsy remain a major challenge for clinicians. In 2018 clinical recommendations for the management of TSC associated epilepsy were published by a panel of European experts.

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Synaptogenesis is the final phase of axonal pathfinding. Its sequences of spatial and temporal development in the immature nervous system are precisely timed and consistent. Synaptophysin, a principal structural glycoprotein of synaptic vesicle membranes regardless of the chemical transmitter substance within, is a reliable means of demonstrating sequences of synaptogenesis in human fetal brain tissue at autopsy and is resistant to postmortem autolysis.

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The aim of this review was to discuss bioethics in prenatal diagnosis and health care after recent legislative and judicial changes affecting reproductive rights, such as the repeal of 'Roe v. Wade' in the United States. We recognize that abortion involves particular moralities that are not universal or shared by all cultures, groups, and individuals.

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Introduction: Current published long-term provincial or territorial congenital anomaly data are lacking for Canada. We report on prevalence (per 1000 total births) and trends in 1997-2019, in Alberta, Canada, for selected congenital anomalies. Associated risk factors are also discussed.

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Background: Limited training in targeted neurological examination makes it challenging for frontline providers to identify newborns with perinatal asphyxia eligible for therapeutic hypothermia. This training is important in the era of telemedicine, where the experts can remotely guide further care of these newborns.

Methods: This randomized controlled pilot study was conducted in a South Indian tertiary hospital.

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Ongoing challenges in diagnosing focal cortical dysplasia (FCD) mandate continuous research and consensus agreement to improve disease definition and classification. An International League Against Epilepsy (ILAE) Task Force (TF) reviewed the FCD classification of 2011 to identify existing gaps and provide a timely update. The following methodology was applied to achieve this goal: a survey of published literature indexed with ((Focal Cortical Dysplasia) AND (epilepsy)) between 01/01/2012 and 06/30/2021 (n = 1349) in PubMed identified the knowledge gained since 2012 and new developments in the field.

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Peripheral neuroblastic tumours of neural crest origin are the most frequent solid neoplasms outside the CNS in children. Neuroblastoma/ganglioneuroblastoma/ganglioneuroma have a natural evolution of histological differentiation over time. Together with mitosis-karyorrhexis index and patient age (International Neuroblastoma Pathology Classification criteria), ganglion cell maturation determines grading and prognosis.

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Article Synopsis
  • Semaphorins and plexins, important for brain development, include the PLXNA3 gene, which affects brain signaling and is linked to conditions like autism and intellectual disabilities in boys with specific genetic variants.
  • This study examined 14 boys with these hemizygous PLXNA3 variants, finding a range of issues such as autism, motor difficulties, and seizures, highlighting a connection between the gene variations and the severity of neurodevelopmental disorders.
  • The findings suggest a potential new X-linked intellectual disability syndrome tied to PLXNA3 variants and emphasize the need for more research on their impact in humans.
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As with many body organs, the human central nervous system contains many structures and cavities that may have had functions in embryonic and fetal life but are vestigial or atrophic at maturity. Examples are the septum pellucidum, remnants of the lamina terminalis, Cajal-Retzius neurons, induseum griseum, habenula, and accessory olfactory bulb. Other structures are transitory in fetal or early postnatal life, disappearing from the mature brain.

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The ILAE classification of Focal Cortical Dysplasia (FCD) from 2011 has quickly gained acceptance in clinical practice and research and is now widely used around the world. This histopathology-based classification scheme proposed three subtypes, that is, FCD Type 1 (with architectural abnormalities of the neocortex), FCD Type 2 (with cytoarchitectural abnormalities of the neocortex) and FCD Type 3 (architectural abnormalities of the neocortex associated with another principle lesion acquired during early life). Valuable knowledge was gathered during the last decade validating the clinical, pathological and genetic classification of FCD Type 2.

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Objective: Focal cortical dysplasia (FCD) is a major cause of difficult-to-treat epilepsy in children and young adults, and the diagnosis is currently based on microscopic review of surgical brain tissue using the International League Against Epilepsy classification scheme of 2011. We developed an iterative histopathological agreement trial with genetic testing to identify areas of diagnostic challenges in this widely used classification scheme.

Methods: Four web-based digital pathology trials were completed by 20 neuropathologists from 15 countries using a consecutive series of 196 surgical tissue blocks obtained from 22 epilepsy patients at a single center.

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Background: The ratio between excitatory (glutamatergic) and inhibitory (GABAergic) inputs into maturing individual cortical neurons influences their epileptic potential. Structural factors during development that alter synaptic inputs can be demonstrated neuropathologically. Increased mitochondrial activity identifies neurons with excessive discharge rates.

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Background: Keratan sulfate (KS) is an abundant proteoglycan in the developing human CNS where it functions as an extracellular axonal guidance molecule, repelling glutamatergic while facilitating GABAergic axons. It ensheaths axonal fascicles. In fetal brain maturation, KS acts as a barrier to axonal penetration.

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Background: The olfactory nerve was conceptualized in the 4th century BC by Alcmaeon and described anatomically by Winslow in 1733. Cranial nerves (CNs) were named and numbered by Soemmerring in 1791. Notions still prevail that the olfactory (CN1) is not a "true" cranial nerve.

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Axons from deep heterotopia do not extend through U-fibers, except transmantle dysplasias. Keratan sulfate (KS) in fetal spinal cord/brainstem median septum selectively repels glutamatergic axons while enabling GABAergic commissural axons. Immunocytochemical demonstration of KS in neocortical resections and forebrain at autopsy was studied in 12 fetuses and neonates 9-41 weeks gestational age (GA), 9 infants, children, and adolescents and 5 patients with focal cortical dysplasias (FCD1a).

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This chapter focuses on the development of the human olfactory system. In this system, function does not require full neuroanatomical maturity. Thus, discrimination of odorous molecules, including a number within the mother's diet, occurs in amniotic fluid after 28-30 weeks of gestation, at which time the olfactory bulbs are identifiable by MRI.

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