Publications by authors named "Frosch M"

Background: Collision tumors, involving two distinct neoplasms in a single anatomical site, are rare. Among these, the metastasis of melanoma into an intracranial meningioma is particularly uncommon, with only four previously reported cases. Melanoma, known for its aggressive metastatic potential, contrasts sharply with the small number of collision tumor reports.

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The locus coeruleus (LC) has been identified as a site that develops phosphorylated tau pathology earlier than cerebral cortex. We present data using high-resolution postmortem MRI and validated tau histopathology in controls and the earliest Braak and Braak (BB) stages (BBI-BBII) in LC. The high-resolution ex vivo MRI provides a 3D volume (quantitative), while the histology reveals tau specificity and severity burden (semi-quantitative).

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Studying comorbidities in early onset Alzheimer disease (AD) may provide an advantageous perspective on their pathogenesis because aging factors may be largely inoperative for these subjects. We compared AD comorbidities between early-onset sporadic cases and American and Colombian cases with PSEN1 mutations. AD neuropathological changes (ADNC) were very severe in all groups but more severe in the PSEN1 groups.

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Introduction: Deep brain stimulation (DBS) of the superolateral branch of the medial forebrain bundle (slMFB) is currently being researched in clinical trials and open case series as a therapeutic option for treatment-resistant major depressive disorder and treatment-resistant obsessive-compulsive disorder (TR-OCD). There are numerous publications describing stimulation in such proximity to the ventral tegmental area (VTA) and open questions remain concerning the stimulation target and its functional environment. As of right now, we are not aware of any publications that compare the typical electrode placements with the histologically supported tractographic depiction of the target structure.

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Human microglia play a pivotal role in neurological diseases, but we still have an incomplete understanding of microglial heterogeneity, which limits the development of targeted therapies directly modulating their state or function. Here, we use single-cell RNA sequencing to profile 215,680 live human microglia from 74 donors across diverse neurological diseases and CNS regions. We observe a central divide between oxidative and heterocyclic metabolism and identify microglial subsets associated with antigen presentation, motility and proliferation.

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The hippocampus is heterogeneous in its architecture. It contributes to cognitive processes such as memory and spatial navigation and is susceptible to neurodegenerative disease. Cytoarchitectural features such as neuron size and neuronal collinearity have been used to parcellate the hippocampal subregions.

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Chronic pain is common among children and adolescents; however, the diagnoses in the newly developed 11th revision of the International Classification of Diseases (ICD-11) chronic pain chapter are based on adult criteria, overlooking pediatric neurodevelopmental differences. The chronic pain diagnoses have demonstrated good clinical applicability in adults, but to date, no field study has examined these diagnoses to the most specific diagnostic level in a pediatric sample. The current study aimed to explore pediatric representation within the ICD-11, with focus on chronic primary pain.

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Annexin A11 mutations are a rare cause of amyotrophic lateral sclerosis (ALS), wherein replicated protein variants P36R, G38R, D40G and D40Y are located in a small helix within the long, disordered N-terminus. To elucidate disease mechanisms, we characterized the phenotypes induced by a genetic loss-of-function and by misexpression of G38R and D40G in vivo. Loss of Annexin A11 results in a low-penetrant behavioural phenotype and aberrant axonal morphology in zebrafish homozygous knockout larvae, which is rescued by human wild-type Annexin A11.

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Article Synopsis
  • The text discusses open-source tools designed for 3D analysis of photographs from dissected human brain slices, which are often underutilized for quantitative studies.
  • These tools can reconstruct a 3D volume and segment brain images into 11 regions per hemisphere, serving as a cost-effective alternative to traditional MRI imaging.
  • Testing shows that the methodology provides accurate 3D reconstructions and can differentiate between Alzheimer's disease cases and healthy controls, with tools available in the FreeSurfer suite.
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Introduction: The entorhinal cortex (EC) and perirhinal cortex (PC) are vulnerable to Alzheimer's disease. A triggering factor may be the interaction of vascular dysfunction and tau pathology.

Methods: We imaged post mortem human tissue at 100 μm with 7 T magnetic resonance imaging and manually labeled individual blood vessels (mean = 270 slices/case).

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A basic assumption underlying induced pluripotent stem cell (iPSC) models of neurodegeneration is that disease-relevant pathologies present in brain tissue are also represented in donor-matched cells differentiated from iPSCs. However, few studies have tested this hypothesis in matched iPSCs and neuropathologically characterized donated brain tissues. To address this, we assessed iPSC-neuron production of β-amyloid (Aβ) Aβ40, Aβ42, and Aβ43 in 24 iPSC lines matched to donor brains with primary neuropathologic diagnoses of sporadic AD (sAD), familial AD (fAD), control, and other neurodegenerative disorders.

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Understanding cellular architectures and their connectivity is essential for interrogating system function and dysfunction. However, we lack technologies for mapping the multiscale details of individual cells and their connectivity in the human organ-scale system. We developed a platform that simultaneously extracts spatial, molecular, morphological, and connectivity information of individual cells from the same human brain.

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Introduction: Amyloid beta and tau pathology are the hallmarks of sporadic Alzheimer's disease (AD) and autosomal dominant AD (ADAD). However, Lewy body pathology (LBP) is found in ≈ 50% of AD and ADAD brains.

Methods: Using an α-synuclein seed amplification assay (SAA) in cerebrospinal fluid (CSF) from asymptomatic (n = 26) and symptomatic (n = 27) ADAD mutation carriers, including 12 with known neuropathology, we investigated the timing of occurrence and prevalence of SAA positive reactivity in ADAD in vivo.

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Article Synopsis
  • Pick's disease is a rare form of frontotemporal dementia characterized by Pick bodies in the brain, which are linked to the MAPT gene and its haplotypes, H1 and H2.
  • The study aimed to investigate how the MAPT H2 haplotype influences the risk, age of onset, and duration of Pick's disease.
  • Data was collected from 338 individuals with confirmed Pick's disease across multiple sites, and associations of MAPT variants with the disease were analyzed using statistical models.
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  • Survival rates for glioblastoma IDH wild-type (GBM) vary, emphasizing the need for improved surgical strategies, particularly given that most recurrences occur close to the resection margin.
  • A predictive model was created to determine which GBMs could achieve radiographic gross-total resection (GTR), showing strong accuracy in forecasting surgical outcomes based on tumor characteristics.
  • Analysis of surgical margins using a rapid method revealed that patients with undetected TERT promoter mutations after GTR had significantly better survival rates compared to those with detectable mutations.
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Human microglia are critically involved in Alzheimer's disease (AD) progression, as shown by genetic and molecular studies. However, their role in tau pathology progression in human brain has not been well described. Here, we characterized 32 human donors along progression of AD pathology, both in time-from early to late pathology-and in space-from entorhinal cortex (EC), inferior temporal gyrus (ITG), prefrontal cortex (PFC) to visual cortex (V2 and V1)-with biochemistry, immunohistochemistry, and single nuclei-RNA-sequencing, profiling a total of 337,512 brain myeloid cells, including microglia.

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Article Synopsis
  • The prosubiculum (ProS) is a distinct neuroanatomical region in the hippocampus, found in mice, monkeys, and humans, lying between CA1 and subiculum (Sub).
  • Researchers identified four unique cytoarchitectural features that differentiate ProS from adjacent subfields: small neurons, lightly stained neurons, superficial clustered neurons, and a zone with fewer cells.
  • The study quantitatively measured the size of ProS pyramidal neurons, finding them to be smaller than those in CA1 and Sub, indicating that ProS may serve specific functional roles within the hippocampal network and highlighting its complex structure.
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We and others have shown that [F]-Flortaucipir, the most validated tau PET tracer thus far, binds with strong affinity to tau aggregates in Alzheimer's (AD) but has relatively low affinity for tau aggregates in non-AD tauopathies and exhibits off-target binding to neuromelanin- and melanin-containing cells, and to hemorrhages. Several second-generation tau tracers have been subsequently developed. [F]-MK-6240 and [F]-PI-2620 are the two that have garnered most attention.

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Clinical improvement following neurosurgical cerebrospinal fluid shunting for presumed idiopathic normal pressure hydrocephalus is variable. Idiopathic normal pressure hydrocephalus patients may have undetected Alzheimer's disease-related cortical pathology that confounds diagnosis and clinical outcomes. In this study, we sought to determine the utility of cortical tissue immuno-analysis in predicting shunting outcomes in idiopathic normal pressure hydrocephalus patients.

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Background: Genetic prion diseases, including Gerstmann-Sträussler-Scheinker disease (GSS), are extremely rare, fatal neurodegenerative disorders, often associated with progressive ataxia and cognitive/neuropsychiatric symptoms. GSS typically presents as a rapidly progressive cerebellar ataxia, associated with cognitive decline. Late-onset cases are rare.

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