10 results match your criteria: "The Netherlands. hankemeier@lacdr.leidenuniv.nl.[Affiliation]"

Background: Isoprostanes and prostaglandins are biomarkers for oxidative stress and inflammation. Their role in Alzheimer's disease (AD) pathophysiology is yet unknown. In the current study, we aim to identify the association of isoprostanes and prostaglandins with the Amyloid, Tau, Neurodegeneration (ATN) biomarkers (Aβ-42, p-tau, and t-tau) of AD pathophysiology in mild cognitive impairment (MCI) subjects.

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Background: Lysophosphatidic acids (LPAs) are bioactive signaling phospholipids that have been implicated in Alzheimer's disease (AD). It is largely unknown whether LPAs are associated with AD pathology and progression from mild cognitive impairment (MCI) to AD.

Methods: The current study was performed on cerebrospinal fluid (CSF) and plasma samples of 182 MCI patients from two independent cohorts.

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The central aim in ecometabolomics and chemical ecology is to pinpoint chemical features that explain molecular functioning. The greatest challenge is the identification of compounds due to the lack of constitutive reference spectra, the large number of completely unknown compounds, and bioinformatic methods to analyze the big data. In this study we present an interdisciplinary methodological framework that extends ultra-performance liquid chromatography coupled to electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC/ESI-QTOF-MS) with data-dependent acquisition (DDA-MS) and the automated classification of fragment peaks into compound classes.

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Pancreatic Ductal Adenocarcinoma (PDAC) is one of the most lethal cancers due to a high chemoresistance and poor vascularization, which results in an ineffective systemic therapy. PDAC is characterized by a high intratumoral pressure, which is not captured by current 2D and 3D in vitro models. Here, we demonstrated a 3D microfluidic interstitial flow model to mimic the intratumoral pressure in PDAC.

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Fast LC-ESI-MS/MS analysis and influence of sampling conditions for gut metabolites in plasma and serum.

Sci Rep

August 2019

Analytical Biosciences and Metabolomics, Division of Systems Biomedicine and Pharmacology, Leiden Academic Center for Drug Research, Leiden University, Leiden, 2333 CC, The Netherlands.

In the past few years, the gut microbiome has been shown to play an important role in various disorders including in particular cardiovascular diseases. Especially the metabolite trimethylamine-N-oxide (TMAO), which is produced by gut microbial metabolism, has repeatedly been associated with an increased risk for cardiovascular events. Here we report a fast liquid chromatography tandem mass spectrometry (LC-MS/MS) method that can analyze the five most important gut metabolites with regards to TMAO in three minutes.

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Article Synopsis
  • Metabolic profiling of cerebrospinal fluid (CSF) holds potential for understanding brain diseases by minimizing ex vivo metabolism during sampling.
  • The study aimed to determine how temperature, centrifugation, and the addition of ethanol affect the concentration of various amines in CSF samples.
  • Results showed that most amines are stable during sampling as long as samples are cooled and processed quickly, though the impact of ethanol on more unstable metabolites requires further research.
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96 perfusable blood vessels to study vascular permeability in vitro.

Sci Rep

December 2017

Division of Analytical Biosciences, LACDR, Leiden University, Leiden, The Netherlands.

Current in vitro models to test the barrier function of vasculature are based on flat, two-dimensional monolayers. These monolayers do not have the tubular morphology of vasculature found in vivo and lack important environmental cues from the cellular microenvironment, such as interaction with an extracellular matrix (ECM) and exposure to flow. To increase the physiological relevance of in vitro models of the vasculature, it is crucial to implement these cues and better mimic the native three-dimensional vascular architecture.

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Quantitative profiling of endocannabinoids and related -acylethanolamines in human CSF using nano LC-MS/MS.

J Lipid Res

March 2017

Division of Analytical Biosciences, Leiden Academic Centre for Drug Research Leiden University, Leiden, The Netherlands

Endocannabinoids, a class of lipid messengers, have emerged as crucial regulators of synaptic communication in the CNS. Dysregulation of these compounds has been implicated in many brain disorders. Although some studies have identified and quantified a limited number of target compounds, a method that provides comprehensive quantitative information on endocannabinoids and related -acylethanolamines (NAEs) in cerebrospinal fluid (CSF) is currently lacking, as measurements are challenging due to low concentrations under normal physiological conditions.

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The translational value of zebrafish high-throughput screens can be improved when more knowledge is available on uptake characteristics of potential drugs. We investigated reference antibiotics and 15 preclinical compounds in a translational zebrafish-rodent screening system for tuberculosis. As a major advance, we have developed a new tool for testing drug uptake in the zebrafish model.

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Elastomeric microvalves as tunable nanochannels for concentration polarization.

Lab Chip

December 2013

Netherlands Metabolomics Centre (NMC), Leiden Academic Centre for Drug Research (LACDR), Einsteinweg 55, 2333CC, Leiden, The Netherlands.

Elastomeric microvalves in poly(dimethylsiloxane) (PDMS) devices are today's paradigm for massively parallel microfluidic operations. Here, we report that such valves can act as nanochannels upon closure. When tuning nanospace heights between ~55 nm and ~7 nm, the nanofluidic phenomenon of concentration polarization could be induced.

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