Case report: Diagnostic challenge: a new multiple sclerosis "relapse" leading to the diagnosis of anaplastic astrocytoma.

Cerebral tumors and multiple sclerosis (MS) can show overlapping clinical and magnetic resonance imaging (MRI) features and even occur concurrently. Due to the emergence of new symptoms, not usually MS related, an MRI was conducted in a 29-year-old woman with relapsing-remitting MS and showed a significant size progression of a parieto-occipital lesion, with mild clinical correlates, such as blurred vision, difficulty in speaking, and headache. Contrast-enhanced MRI and fluorothymidine positron-emission tomography (PET) did not point toward neoplasm, a lesion biopsy, however, showed astrocytoma, which was confirmed as grade III astrocytoma after the radical resection of the tumor. In the case of an atypical lesion, a tumor should be considered in patients with MS. A small fraction of high-grade gliomas show no enhancement on MRI and no hypermetabolism on PET. Biopsy proved to be the essential step in a successful diagnostic workup. To the best of our knowledge, this is the first case of anaplastic astrocytoma with these radiological features reported in a patient with MS.

Light sheet fluorescence microscopy of optically cleared brains for studying the glymphatic system.

Fluid transport in the perivascular space by the glia-lymphatic (glymphatic) system is important for the removal of solutes from the brain parenchyma, including peptides such as amyloid-beta which are implicated in the pathogenesis of Alzheimer's disease. The glymphatic system is highly active in the sleep state and under the influence of certain of anaesthetics, while it is suppressed in the awake state and by other anaesthetics. Here we investigated whether light sheet fluorescence microscopy of whole optically cleared murine brains was capable of detecting glymphatic differences in sleep- and awake-mimicking anaesthesia, respectively. Using light-sheet imaging of whole brains, we found anaesthetic-dependent cerebrospinal fluid (CSF) influx differences, including reduced tracer influx along tertiary branches of the middle cerebral artery and reduced influx along dorsal and anterior penetrating arterioles, in the awake-mimicking anaesthesia. This study establishes that light sheet microscopy of optically cleared brains is feasible for quantitative analyses and can provide images of the entire glymphatic system in whole brains.

Differentiation of neural rosettes from human pluripotent stem cells in vitro is sequentially regulated on a molecular level and accomplished by the mechanism reminiscent of secondary neurulation.

Development of neural tube has been extensively modeled in vitro using human pluripotent stem cells (hPSCs) that are able to form radially organized cellular structures called neural rosettes. While a great amount of research has been done using neural rosettes, studies have only inadequately addressed how rosettes are formed and what the molecular mechanisms and pathways involved in their formation are. Here we address this question by detailed analysis of the expression of pluripotency and differentiation-associated proteins during the early onset of differentiation of hPSCs towards neural rosettes. Additionally, we show that the BMP signaling is likely contributing to the formation of the complex cluster of neural rosettes and its inhibition leads to the altered expression of PAX6, SOX2 and SOX1 proteins and the rosette morphology. Finally, we provide evidence that the mechanism of neural rosettes formation in vitro is reminiscent of the process of secondary neurulation rather than that of primary neurulation in vivo. Since secondary neurulation is a largely unexplored process, its understanding will ultimately assist the development of methods to prevent caudal neural tube defects in humans.