Diffuse Leptomeningeal Glioneuronal Tumor in an Adult: A Diagnostic Challenge

Here we report a rare case of diffuse leptomeningeal glioneuronal tumor (DLGNT) in a 35-year-old man, who was misdiagnosed twice as having tuberculosis meningitis and later racemose neurocysticercosis. His delayed diagnosis of DLGNT might be due to prevalence of tuberculosis in our country, similarity in magnetic resonance imaging finding of prominent leptomeningeal enhancement in different cisterns of brain, and extreme rarity of DLGNT in the adults. So, it should be differentiated clinically and radiographically from granulomatous or infectious conditions. Hence, a timely histologic diagnosis through a leptomeningeal biopsy of the brain and spinal cord in case of unusual leptomeningeal enhancement with uncertain laboratory findings is essential because cytological examination of the cerebrospinal fluid in DLGNT is known to be negative.

Victor Horsley

Sir Victor Horsley (1857–1916) was a pioneer who shaped the development of neurosurgery and the direction of clinical medicine through his work with the British Medical Association, Medical Defence Union, and General Medical Council. Before the nervous system could be imaged, Horsley operated successfully on the brain and spinal cord, and performed palliative procedures on patients dying from brain tumours. Nevertheless, he became a social pariah due to his support for nationalised health insurance, child welfare and women's rights, amongst other causes. In this fascinating biography, leading neurologist Dr Michael J. Aminoff places Horsley's life and work in the context of the society in which he lived and explores his influence on the development of neurosurgery and social policies still in effect. The many underlying themes to the book include the interplay of science and politics, and the responsibility of physicians to themselves and for the welfare of society.

Hemorrhagic Meningoencephalomyelitis Due to Ectopic Localization of Aelurostrongylus abstrusus in a Cat: First Case Report

The lungworm Aelurostrongylus abstrusus is one of the main causes of respiratory diseases in cats worldwide. This report describes the unusual case of a kitten infected with A. abstrusus and presented to a veterinary clinic in Brazil with lethargy, dysphagia, non-ambulatory tetraplegia, and pelvic limbs bilateral myoclonus. The clinical picture of the kitten worsened with generalized flaccid tetraplegia and death a few days after hospitalization. At necropsy, hemorrhagic necrosis and subarachnoid hemorrhages were detected in several areas of the central nervous system. Nematode stages were found at post-mortem histological examinations in lungs, cerebellum, subarachnoid space of the brain and spinal cord. Microscopic and molecular (PCRs-coupled-sequencing protocols) examination showed the presence of A. abstrusus in histological samples. This study describes the first neurological aelurostrongylosis due to ectopic localization of adult worms in the central nervous system of a cat, causing acute hemorrhagic multifocal meningoencephalomyelitis. Further studies are necessary to elucidate whether unusual localizations and the migration of A. abstrusus are more frequent than expected.

Encephalomyelitis Caused by Balamuthia mandrillaris in a Woman With Breast Cancer: A Case Report and Review of the Literature

Balamuthia mandrillaris is one cause of a rare and severe brain infection called granulomatous amoebic encephalitis (GAE), which has a mortality rate of >90%. Diagnosis of Balamuthia GAE is difficult because symptoms are non-specific. Here, we report a case of Balamuthia amoebic encephalomyelitis (encephalitis and myelitis) in a woman with breast cancer. She sustained trauma near a garbage dump 2 years ago and subsequently developed a skin lesion with a Mycobacterium abscessus infection. She experienced dizziness, lethargy, nausea and vomiting, inability to walk, and deterioration of consciousness. Next-generation sequencing of cerebrospinal fluid (CSF) samples revealed B. mandrillaris, and MRI of both brain and spinal cord showed abnormal signals. T-cell receptor (TCR) sequencing of the CSF identified the Top1 TCR. A combination of amphotericin B, flucytosine, fluconazole, sulfamethoxazole, trimethoprim, clarithromycin, pentamidine, and miltefosine was administrated, but she deteriorated gradually and died on day 27 post-admission.

Pathogenesis of Aquatic Bird Bornavirus in Muscovy Ducks

Aquatic bird bornavirus (ABBV), a type of avian bornavirus, has been associated with inflammation of the central and peripheral nervous systems and neurological disease in wild waterfowl in North America and Europe. The potential of ABBV to infect and cause lesions in commercial waterfowl species is unknown. The aim of this study was to determine the ability of ABBV to infect and cause disease in day-old Muscovy ducks (n = 174), selected as a representative domestic waterfowl. Ducklings became infected with ABBV through both intracranial and intramuscular infection routes: upon intramuscular infection, the virus spread centripetally to the central nervous system (brain and spinal cord), while intracranial infection led to virus spread to the spinal cord, kidneys, proventriculus, and gonads (centrifugal spread). Infected birds developed both encephalitis and myelitis by 4 weeks post infection (wpi), which progressively subsided by 8 and 12 wpi. Despite development of microscopic lesions, clinical signs were not observed. Only five birds had choanal and/or cloacal swabs positive for ABBV, suggesting a moderate potential of Muscovy ducks to shed the virus. This is the first study to document the pathogenesis of ABBV in poultry species, and confirms the ability of ABBV to infect commercial waterfowl.

Optogenetic Interrogation of Circuits Following Neurotrauma

Biological and engineering strategies for neural repair and recovery from neurotrauma continue to emerge at a rapid pace. Until recently, studies of the impact of neurotrauma and repair strategies on the reorganization of the central nervous system have focused on broadly defined circuits and pathways. Optogenetic modulation and recording methods now enable the interrogation of precisely defined neuronal populations in the brain and spinal cord, allowing unprecedented precision in electrophysiological and behavioral experiments. This mini-review summarizes the spectrum of light-based tools that are currently available to probe the properties and functions of well-defined neuronal subpopulations in the context of neurotrauma. In particular, we highlight the challenges to implement these tools in damaged and reorganizing tissues, and we discuss best practices to overcome these obstacles.

Multiple Functions of the Dmrt Genes in the Development of the Central Nervous System

The Dmrt genes encode the transcription factor containing the DM (doublesex and mab-3) domain, an intertwined zinc finger-like DNA binding module. While Dmrt genes are mainly involved in the sexual development of various species, recent studies have revealed that Dmrt genes, which belong to the DmrtA subfamily, are differentially expressed in the embryonic brain and spinal cord and are essential for the development of the central nervous system. Herein, we summarize recent studies that reveal the multiple functions of the Dmrt genes in various aspects of vertebrate neural development, including brain patterning, neurogenesis, and the specification of neurons.

Early stage differentiation of glia in human and mice.

Central nervous system macroglia (astrocytes and oligodendrocytes) are required for normal brain development and function, and are among the last cells to emerge during neurodevelopment. Many questions remain about their emergence in the brain and spinal cord, including how early glial fates are specified during development or differen- tiation, and similarly when subtypes of glia are specified. Here, we used single-cell RNA sequencing (scRNAseq) to analyze ~90,000 cells across multiple timepoints during the differentiation of astrocytes and oligodendrocytes from human induced pluripotent stem cells and mouse embryonic stem cells. Using time series analysis of gene expres- sion, we uncovered multiple genes involved in fate specification of glial subtypes in both species. We examined gene expression changes during intermediate states of glial specification, and were able to identify genes that were correlated with the choice between neuron versus glia in both species. Using our scRNAseq data we optimized previous mouse astrocyte differentiation protocols by highlighting and removing non-required transition states and decreasing the overall protocol from 3 weeks to less than 12 days. Our data will be useful for researchers interested in optimizing glial differentiations in either species, and provide a window into human glial differentiation, which is difficult to study given its lateness in development.