Surgical cavity dilatation after resection of IDH-mutated astrocytoma of the mesial temporal lobe: illustrative cases

Background: Space-occupying tumor bed cysts may exceptionally happen after the resection of diffuse low-grade glioma. Their mechanism and management remain debated. The authors report two cases of tumor bed cysts occurring after the resection of a left temporal diffuse low-grade glioma with two different evolutions. Observations: The first patient showed a spontaneous decrease in the cyst volume and did not report any symptoms. In contrast, the second patient showed a progressive increase in the cyst volume and reported headaches and difficulties in finding words. Endoscopic cyst fenestration was performed and led to symptom relief and normalization of the surgical cavity. Lessons: A tumor bed cyst is a rare complication of temporal low-grade glioma resection. Its formation is due to entrapment of the choroid plexus in the temporal horn widely opened into the surgical cavity. Endoscopic cyst fenestration should be offered only in symptomatic cases. https://thejns.org/doi/10.3171/CASE23674

Cost modeling of lithium-ion battery cells for automotive applications

The purpose of this study was to highlight the technical and economic issues arising in lithium-ion cells for automotive applications, and to indicate some potential solutions to lower the cost. This topic has already been the subject of some studies, but, although of primary importance, the role on cost of a cell design parameter, the electrode coating thickness, has rarely been described. This study intends to explore particularly the influence of this parameter. To do so, the cost of cells with four positive electrode materials (NMC, NCA, LFP, and LMO), and the same negative electrode material are compared at several electrode thickness. The cost of these cells is computed using an innovative model and varies between 230 and 400 $ per kWh. With the assumptions used, it appears that the potential savings resulting from doubling the electrode coating thickness from 50 to 100 lm at a given porosity represent roughly 25% of the cell cost. The electrode coating thickness emerges as an essential parameter for an unbiased cells cost comparison. This article gives a view ofof the current lithium-ion cells costs, and provides guidelines to lower cells cost.ANRT CIFR

Light in the cave: Opal coating detection by UV-light illumination and fluorescence in a rock art context

The formation of silica coatings on the cave walls of the Points cave raises questions about the analytical access to the specificities of the pictorial material (geochemistry and petrography); and about the state of conservation of the rock art. Conventional in situ spectroscopic techniques (pXRF, pRaman) are ineffective to identify and characterize these coatings. In this study, we propose to use a UV fluorescence method for the detection and recognition of opaline coatings, based on the fluorescence specificities of the uranyl-silica complexes composing these deposits. Spectral identification using UV laser-induced fluorescence spectroscopy coupled with UV illumination was performed on samples, µ-samples and on the walls of the Grotte aux Points rock art site. The well-defined peaks observed in the fluorescence emission spectra due to uranyl ions validate the detection of the complex opal-uranyl and its correspondence with the green fluorescence observed under UV light at micro and macroscopic scales. In situ optical measurements under UV illumination reveal the presence of an opal layer, in particular on the rock art walls of the cave. Observations on the occurrence and distribution of opal provide the first insights into the evolution of the walls and the chronological constraints on the development of the opal layer. regarding the interactions between the silica coating and the pigment suggested by the multi-scale observations of the µ-samples, it opens the question of rock art conservation. Thus, by developing a specific method of non-destructive characterization of opal coatings, this study starts a new approach for the study of the taphonomy of decorated walls and proposes to use siliceous mineralization both as a marker of the natural history of caves and as an index of their use by ancient human groups

Gene expression mapping of histone deacetylases and co-factors, and correlation with survival time and 1H-HRMAS metabolomic profile in human gliomas

Primary brain tumors are presently classified based on imaging and histopathological techniques, which remains unsatisfaying. We profiled here by quantitative real time PCR (qRT-PCR) the transcripts of eighteen histone deacetylases (HDACs) and a subset of transcriptional co-factors in non-tumoral brain samples from 15 patients operated for epilepsia and in brain tumor samples from 50 patients diagnosed with grade II oligodendrogliomas (ODII, n = 9), grade III oligodendrogliomas (ODIII, n = 22) and glioblastomas (GL, n = 19). Co-factor transcripts were significantly different in tumors as compared to non-tumoral samples and distinguished different molecular subgroups of brain tumors, regardless of tumor grade. Among all patients studied, the expression of HDAC1 and HDAC3 was inversely correlated with survival, whereas the expression of HDAC4, HDAC5, HDAC6, HDAC11 and SIRT1 was significantly and positively correlated with survival time of patients with gliomas. (1)H-HRMAS technology revealed metabolomically distinct groups according to the expression of HDAC1, HDAC4 and SIRT1, suggesting that these genes may play an important role in regulating brain tumorigenesis and cancer progression. Our study hence identified different molecular fingerprints for subgroups of histopathologically similar brain tumors that may enable the prediction of outcome based on the expression level of co-factor genes and could allow customization of treatment

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

Multiancestry analysis of the HLA locus in Alzheimer’s and Parkinson’s diseases uncovers a shared adaptive immune response mediated by HLA-DRB1*04 subtypes

Across multiancestry groups, we analyzed Human Leukocyte Antigen (HLA) associations in over 176,000 individuals with Parkinson’s disease (PD) and Alzheimer’s disease (AD) versus controls. We demonstrate that the two diseases share the same protective association at the HLA locus. HLA-specific fine-mapping showed that hierarchical protective effects of HLA-DRB1*04 subtypes best accounted for the association, strongest with HLA-DRB1*04:04 and HLA-DRB1*04:07, and intermediary with HLA-DRB1*04:01 and HLA-DRB1*04:03. The same signal was associated with decreased neurofibrillary tangles in postmortem brains and was associated with reduced tau levels in cerebrospinal fluid and to a lower extent with increased Aβ42. Protective HLA-DRB1*04 subtypes strongly bound the aggregation-prone tau PHF6 sequence, however only when acetylated at a lysine (K311), a common posttranslational modification central to tau aggregation. An HLA-DRB1*04-mediated adaptive immune response decreases PD and AD risks, potentially by acting against tau, offering the possibility of therapeutic avenues

Surgical Approach to the Cavernous Sinus and Middle Cranial, Pterygoid Fossa

The cavernous sinus is a very complex area, and surgical treatment requires detailed anatomical knowledge and familiarity with its relationship to surrounding structures. By exposing the lateral wall of the cavernous sinus with the extradural approach, it is possible to pass through the triangular corridor of the cavernous sinus and perform surgical treatment for diseases such as trigeminal schwannoma and meningioma inside and outside the cavernous sinus. In addition to the extradural infratemporal fossa approach, the extradural infratemporal fossa to the pterygoid fossa and the approach to the paranasal sinuses can be safely performed by inserting the endoscope into the bone corridor of the middle cranial fossa. Furthermore, in the last decade, transnasal endoscopic skull based approaches have further developed, facilitating surgical access to the cavernous sinus. The cavernous sinus is an unattachable site due to the complex structure of multiple nerves, veins, and internal carotid arteries, but if the anatomy of the cavernous sinus is known well we can treat this complex site. As for the choice of approach to the cavernous sinus, a better understanding of the anatomy surrounding the cavernous sinus will allow a rational choice between transcranial and transnasal approaches

Apports de l'IRM et de la radiochirurgie dans la prise en charge thérapeutique des méningiomes du sinus caverneux. (A propos de 48 observations)

STRASBOURG-Medecine (674822101) / SudocSudocFranceF

Endoscopic Approach of the Insula Through the Anterior Middle Temporal Gyrus: A Feasibility Study in the Laboratory

International audienceBACKGROUNDInsular glioma surgery still represents a challenge. Nonetheless, advances in microsurgical anatomy and brain mapping techniques have allowed an increase in the extent of resection with acceptable morbidity rates. Transsylvian and transcortical approaches constitute the main surgical corridors, the latter providing considerable advantages and a high degree of reliability. Nevertheless, both surgical corridors yield remarkable difficulties in reaching the most posterior insular region.OBJECTIVETo study the feasibility of an endoscopic transtemporal approach in brain specimens, with the aim to provide a suitable access for posterior insular region.METHODSFour postmortem human hemispheres, embalmed using Klingler's technique, were dissected by means of a 30° rigid endoscope. The specimens underwent magnetic resonance imaging scans and, using the neuronavigation system, we were able to design a safe cortical window and an optimized endoscopic trajectory for the posterior insular dissection.RESULTSInsular dissection was led subpially through a small 2-cm cortical access, located in the anterior part of the middle temporal gyrus. During the posterior insula dissection, the endoscope allowed for optimized surgical view all along the long gyri, up to the posterior insular point. Anterior insular dissection was accomplished with more difficulties, as the endoscopic trajectory was not aligned to the axis of the short gyri.CONCLUSIONThis new surgical approach provides a favorable transcortical access to reach the most posterior insular portion. It seems to be a promising tool, in combination with intraoperative functional brain mapping, to further improve extent of resection rates in insular glioma surgery

Cost modeling of lithium-ion battery cells for automotive applications

The purpose of this study was to highlight the technical and economic issues arising in lithium-ion cells for automotive applications, and to indicate some potential solutions to lower the cost. This topic has already been the subject of some studies, but, although of primary importance, the role on cost of a cell design parameter, the electrode coating thickness, has rarely been described. This study intends to explore particularly the influence of this parameter. To do so, the cost of cells with four positive electrode materials (NMC, NCA, LFP, and LMO), and the same negative electrode material are compared at several electrode thickness. The cost of these cells is computed using an innovative model and varies between 230 and 400 $ per kWh. With the assumptions used, it appears that the potential savings resulting from doubling the electrode coating thickness from 50 to 100 μm at a given porosity represent roughly 25% of the cell cost. The electrode coating thickness emerges as an essential parameter for an unbiased cells cost comparison. This article gives a view of the current lithium-ion cells costs, and provides guidelines to lower cells cost