Seven microaneurysms: Description of an experimental rodent model for neurovascular training

AIM: To demonstrate the microsurgical procedures, and to evaluate the feasibility of living models of experimental neurovascular training by developing new complex vascular exercises mimicking the most common intracranial aneurysms. MATERIAL and METHODS: The procedures were performed under a Zeiss (OPMI pico f170) microscope using basic microsurgery instruments, 10/0 Nylon and blue Polypropylene micro-sutures. We selected adult albino Wistar rats weighing between 258 and 471g each. Seven different aneurysm types were created using carotid, jugular, cava, aorta and femoral vessels. RESULTS: Seven types of aneurysm were designed and created in the rat with a high-medium successful rate. There are differences in terms of realism and the difficulty of performance, according to the different types: lateral wall, bifurcation, top of the basilar, fusiform, fusiform + involved branch, Anterior Communicating Artery (ACoA) and giant. The steps and technical issues to produce these exercises are described. CONCLUSION: We show the feasibility of creating several types of aneurysm using different vessels in a rodent model. Training on these models help to improve microsurgical skills, allowing safe practice for neurosurgeons in all stages of their caree

The hippocampus as the switchboard between perception and memory.

Adaptive memory recall requires a rapid and flexible switch from external perceptual reminders to internal mnemonic representations. However, owing to the limited temporal or spatial resolution of brain imaging modalities used in isolation, the hippocampal–cortical dynamics supporting this process remain unknown. We thus employed an object-scene cued recall paradigm across two studies, including intracranial electroencephalography (iEEG) and high-density scalp EEG. First, a sustained increase in hippocampal high gamma power (55 to 110 Hz) emerged 500 ms after cue onset and distinguished successful vs. unsuccessful recall. This increase in gamma power for successful recall was followed by a decrease in hippocampal alpha power (8 to 12 Hz). Intriguingly, the hippocampal gamma power increase marked the moment at which extrahippocampal activation patterns shifted from perceptual cue toward mnemonic target representations. In parallel, source-localized EEG alpha power revealed that the recall signal progresses from hippocampus to posterior parietal cortex and then to medial prefrontal cortex. Together, these results identify the hippocampus as the switchboard between perception and memory and elucidate the ensuing hippocampal–cortical dynamics supporting the recall process.post-print1844 K

Atypical clinical presentation and long-term survival in a patient with optic nerve medulloepithelioma: a case report

<p>Abstract</p> <p>Introduction</p> <p>Medulloepithelioma is a rare congenital tumor of the primitive medullary neuroepithelium. A significant proportion of patients with medulloepithelioma arising from the optic nerve die from intracranial spread or cerebral metastasis. Because it has no known distinct clinical features and because of its low frequency, this tumor presents within the first two to six years of life and is usually misdiagnosed clinically as a different type of optic nerve tumor. Here, we describe a new and atypical case of medulloepithelioma of the optic nerve in a 12-year-old boy. To the best of our knowledge, he is the oldest reported patient to present with this disease and, now as an adult, has the longest documented period of disease-free survival.</p> <p>Case presentation</p> <p>A 12-year-old Caucasian boy with headache and unilateral amaurosis was referred for a presumed optic nerve glioma to our hospital. A computed tomography scan showed optic nerve enlargement, and fundoscopy showed a whitish mass at the optic disc. Our patient had been followed at his local hospital for four years for an 'optic disc cyst' with no change or progression. He experienced mild progressive visual impairment during that period. He was admitted for resection, and a histopathological analysis revealed a medulloepithelioma of the optic nerve. Supplemental orbital radiotherapy was performed. He remained disease-free for 25 years.</p> <p>Conclusions</p> <p>Medulloepithelioma of the optic nerve can clinically mimic more common pediatric tumors, such as optic glioma, meningioma, or retinoblastoma. Thus, medulloepithelioma should be included in the differential diagnoses of pediatric optic nerve lesions. Fundoscopy in these patients may provide relevant information for diagnosis. Anterior optic nerve medulloepitheliomas may behave differently from and have a better prognosis than medulloepitheliomas that have a more posterior location. Our case report illustrates that long-term survival can be achieved in patients with this malignant tumor.</p

Diffuse leptomeningeal glioneuronal tumour: where to biopsy? Case report and literature review.

PURPOSE: Diffuse leptomeningeal glioneuronal tumour (DLGT) is an infrequent entity. Diagnosis is made with biopsy but with so few cases described management, prognosis remains undefined. There are not currently any articles regarding most effective place to biopsy. METHODS: Current literature review and introduction of the case of a 3-year-old male presenting at the emergency room with irritability, vomiting and nuchal rigidity. A head CT was made showing tetraventricular enlargement and a posterior fossa cyst. RESULTS: Patient underwent urgent ventriculoperitoneal shunting surgery with complete symptomp resolution. Brain MRI showed diffuse leptomeningeal enhancing, predominantly in basal cisterns, and multiple cystic-solid lesions along the neural axis. After ruling other conditions, a biopsy among intraoperative samples, was obtained of a PET positive gadolinium spinal enhancing lesion at D8 level, with the final diagnosis of DLGT. CONCLUSION: DLGT can present as acute hydrocephalus. Biopsy stablishes the diagnosis but the place to take the sample can be difficult to select. Our experience suggests that PET-CT and intraoperative biopsy analysis can improve the effectivity of a representative sample

Management of a ruptured intraventricular aneurysm arising from distal anterior choroidal artery (AChA): pediatric case report.

Intracranial aneurysms arising from the distal anterior choroidal artery (AChA) are uncommon entities, with less than 30 cases reported. A 4-year-old boy was admitted to the Emergency Department with a sudden onset of severe headache and vomiting. CT scan of the head showed signs of intraventricular hemorrhage (IVH) and subarachnoid hemorrhage (SAH). Cerebral angiography revealed a right AChA aneurysm arising from a distal intraventricular branch with an associated microarteriovenous malformation (microAVM). Following a multidisciplinary assessment, the patient underwent surgical clipping. An ipsilateral transcortical transparietal approach was utilized. Early postoperative deficits were not found, and good clinical and radiological outcomes were assessed at long-term follow-up. Postoperative cerebral angiography showed complete exclusion and resection of both aneurysm and AVM. Surgery for intracranial aneurysms in this location can be challenging; however, good surgical and neurological outcomes can be achieved. The present work highlights the value of multidisciplinary assessment in the decision-making process in complex pediatric neurovascular pathology, especially when facing rare cases like this one, which represents the youngest case of a ruptured distal AChA aneurysm reported in the literature

Table1_Case report: A third variant in the 5′ UTR of TWIST1 creates a novel upstream translation initiation site in a child with Saethre-Chotzen syndrome.docx

Introduction: Saethre-Chotzen syndrome, a craniosynostosis syndrome characterized by the premature closure of the coronal sutures, dysmorphic facial features and limb anomalies, is caused by haploinsufficiency of TWIST1. Although the majority of variants localize in the coding region of the gene, two variants in the 5′ UTR have been recently reported to generate novel upstream initiation codons.Methods: Skeletal dysplasia Next-generation sequencing (NGS) panel was used for genetic analysis in a patient with bicoronal synostosis, facial dysmorphisms and limb anomalies. The variant pathogenicity was assessed by a luciferase reporter promoter assay.Results: Here, we describe the identification of a third ATG-creating de novo variant, c.-18C>T, in the 5′ UTR of TWIST1 in the patient with a clinical diagnosis of Saethre-Chotzen syndrome. It was predicted to create an out-of-frame new upstream translation initiation codon resulting in a 40 amino acid larger functionally inactive protein. We performed luciferase reporter promoter assays to demonstrate that the variant does indeed reduce translation from the main open reading frame.Conclusion: This is the third variant identified in this region and confirms the introduction of upstream ATGs in the 5′ UTR of TWIST1 as a pathogenic mechanism in Saethre-Chotzen syndrome. This case report shows the necessity for performing functional characterization of variants of unknown significance within national health services.</p