Publications by authors named "Naessens M"

The consequences of frontotemporal lobar degeneration include changes in prefrontal cortical neurophysiology, with abnormalities of neural dynamics reported in the beta frequency range (14-30 Hz) that correlate with functional severity. We examined beta dynamics in two clinical syndromes associated with frontotemporal lobar degeneration: the behavioral variant of frontotemporal dementia (bvFTD) and progressive supranuclear palsy (PSP). Whilst these two syndromes are partially convergent in cognitive effects, they differ in disease mechanisms such as molecular pathologies and prefrontal atrophy.

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Article Synopsis
  • The corticobasal syndrome (CBS) is a complex movement disorder that can lead to cognitive impairment, often linked to either corticobasal degeneration or Alzheimer's disease, but with differing underlying causes.
  • Researchers studied synaptic loss in 25 patients with CBS compared to 32 healthy controls, using advanced imaging techniques to assess synaptic density and brain volume.
  • Results showed that CBS patients had increased tau levels and gray matter loss, with more pronounced synaptic loss in those without β-amyloid, suggesting different treatment approaches may be needed based on the presence of Alzheimer's pathology.
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There is extensive synaptic loss from frontotemporal lobar degeneration, in preclinical models and human in vivo and post mortem studies. Understanding the consequences of synaptic loss for network function is important to support translational models and guide future therapeutic strategies. To examine this relationship, we recruited 55 participants with syndromes associated with frontotemporal lobar degeneration and 24 healthy controls.

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Self-report scales are widely used in cognitive neuroscience and psychology. However, they rest on the central assumption that respondents engage meaningfully. We hypothesise that this assumption does not hold for many patients, especially those with syndromes associated with frontotemporal lobar degeneration.

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We present a hierarchical empirical Bayesian framework for testing hypotheses about neurotransmitters' concertation as empirical prior for synaptic physiology using ultra-high field magnetic resonance spectroscopy (7T-MRS) and magnetoencephalography data (MEG). A first level dynamic causal modelling of cortical microcircuits is used to infer the connectivity parameters of a generative model of individuals' neurophysiological observations. At the second level, individuals' 7T-MRS estimates of regional neurotransmitter concentration supply empirical priors on synaptic connectivity.

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Background: Synaptic loss is characteristic of many neurodegenerative diseases; it occurs early and is strongly related to functional deficits.

Objective: In this longitudinal observational study, we determine the rate at which synaptic density is reduced in the primary tauopathies of progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD), and we test the relationship with disease progression.

Methods: Our cross-sectional cohort included 32 participants with probable PSP and 16 with probable CBD (all amyloid-negative corticobasal syndrome), recruited from tertiary care centers in the United Kingdom, and 33 sex- and age-matched healthy control subjects.

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Objective: Synaptic loss is an early feature of neurodegenerative disease models, and is severe in post mortem clinical studies, including frontotemporal dementia. Positron emission tomography (PET) with radiotracers that bind to synaptic vesicle glycoprotein 2A enables quantification of synaptic density in vivo. This study used [ C]UCB-J PET in participants with behavioral variant frontotemporal dementia (bvFTD), testing the hypothesis that synaptic loss is severe and related to clinical severity.

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There is a pressing need to accelerate therapeutic strategies against the syndromes caused by frontotemporal lobar degeneration, including symptomatic treatments. One approach is for experimental medicine, coupling neurophysiological studies of the mechanisms of disease with pharmacological interventions aimed at restoring neurochemical deficits. Here we consider the role of glutamatergic deficits and their potential as targets for treatment.

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Background: Progressive reading impairment is an early and debilitating symptom of posterior cortical atrophy (PCA) arising from the progressive deterioration of visual processing skills.

Objective: The goal of this study was to test the effectiveness of a purpose-built reading app (ReadClear) co-produced with people living with PCA and designed to reduce the reading difficulties experienced by this population (e.g.

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The conditional Cre/loxP system and/or the doxycycline (Dox) inducible Tet-on/off system are widely used in mouse transgenesis but often require time consuming, inefficient cloning/screening steps and extensive mouse breeding strategies. We have therefore developed a highly efficient Gateway- and recombinase-mediated cassette exchange (RMCE)-compatible system to target conditional and/or inducible constructs to the ROSA26 locus of F1 hybrid Bl6/129 ESCs, called G4 ROSALUC ESCs. By combining the Cre/loxP system with or without the inducible Tet-on system using Gateway cloning, we can rapidly generate spatial and/or temporal controllable gain-of-function constructs that can be targeted to the RMCE-compatible ROSA26 locus of the G4 ROSALUC ESCs with efficiencies close to 100 %.

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Mdm2 and Mdm4 are critical negative regulators of p53. A large body of evidence indicates that elevated expression of either Mdm2 or Mdm4 may favor tumor formation by inhibiting p53 tumor suppression function. To explore this possibility in vivo, we generated conditional Mdm2 and Mdm4 transgenic mice.

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To determine the role of vascular endothelial growth factor (Vegf) in embryonic erythroid development we have deleted or overexpressed Vegf specifically in the erythroid lineage using the EpoR-iCre transgenic line in combination with Cre/loxP conditional gain and loss of function Vegf alleles. ROSA26 promoter-based expression of the Vegf(164) isoform in the early erythroid lineage resulted in a differentiation block of primitive erythroid progenitor (EryP) development and a partial block in definitive erythropoiesis between the erythroid burst-forming unit and erythroid colony-forming unit stages. Decreased mRNA expression levels of the key erythroid transcription factor Gata1 were causally linked to this phenotype.

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Vascular endothelial growth factor (VEGF) and beta-catenin both act broadly in embryogenesis and adulthood, including in the skeletal and vascular systems. Increased or deregulated activity of these molecules has been linked to cancer and bone-related pathologies. By using novel mouse models to locally increase VEGF levels in the skeleton, we found that embryonic VEGF over-expression in osteo-chondroprogenitors and their progeny largely pheno-copied constitutive beta-catenin activation.

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The ability to rapidly and efficiently generate reliable Cre/loxP conditional transgenic mice would greatly complement global high-throughput gene targeting initiatives aimed at identifying gene function in the mouse. We report here the generation of Cre/loxP conditional ROSA26-targeted ES cells within 3-4 weeks by using Gateway cloning to build the target vectors. The cDNA of the gene of interest can be expressed either directly by the ROSA26 promoter providing a moderate level of expression or by a CAGG promoter placed in the ROSA26 locus providing higher transgene expression.

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The genus Gluconobacter comprises some of the most frequently used microorganisms when it comes to biotechnological applications. Not only has it been involved in "historical" production processes, such as vinegar production, but in the last decades many bioconversion routes for special and rare sugars involving Gluconobacter have been developed. Among the most recent are the biotransformations involved in the production of L-ribose and miglitol, both very promising pharmaceutical lead molecules.

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Certain strains of Gluconobacter oxydans have been known since the 1940s to produce the enzyme dextran dextrinase (DDase; EC2.4.1.

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Response surface methodology (RSM) and a five-level three-factor central composite rotatable design (CCRD) were used to evaluate the effect of glycerol and peptone concentration and initial pH on dextran dextrinase (DDase) production by Gluconobacter oxydans. Optimal fermentation conditions were 20.59 g/l of glycerol, 6.

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Multiple forms of one enzyme occur in a wide variety of microorganisms. Their synthesis is often dependent on culture characteristics such as medium composition, physico-chemical parameters, culture age and the presence of inducing or inhibiting agents. Multiform enzymes increase the capability of the producing organism to adapt to and cope with a wide variety of environmental changes, such that the physiological advantages outweigh the apparent wasteful hyperproduction of multiple forms of one enzyme.

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A new biosensor is constructed for the detection of some herbicides based on kinetic measurements of chlorophyll-a fluorescence in Chlorella vulgaris cells. The microalgae are immobilized on removable membranes placed in front of the tip of an optical fiber bundle inside a homemade microcell. C.

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This report describes a patient with permanent hearing loss after spinal anesthesia. The literature is reviewed, particularly concerning incidence and possible causes. The incidence is surprisingly high and related to the size of the needle.

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