Publications by authors named "Ron M A Heeren"

Mass spectrometry imaging (MSI) maps the spatial distributions of chemicals on chemically complex surfaces. MSI offers unrivaled sensitivity and information density with each pixel comprising a mass spectrum. Over the past three decades, numerous technological developments have enabled MSI to evolve into a mainstream technique for untargeted molecular and elemental imaging with wide-spread applications ranging from material analysis to life sciences and clinical diagnostics.

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Caenorhabditis elegans (C. elegans) is an important model organism for studying fat storage and lipid metabolism. Mass-spectrometry imaging (MSI) is an emerging technology for mapping the spatial distribution of lipids.

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Infrared ion spectroscopy (IRIS) is a tandem mass spectrometry (MS) technique that generates structurally diagnostic vibrational spectra for mass-selected ions trapped in a mass spectrometer. Until now, IRIS applications for biological samples have primarily focused on solution-based analyses, such as body fluids (e.g.

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In acute lymphoblastic leukemia (ALL), hypermethylation of the asparagine synthetase (ASNS) gene promoter, leading to low levels of ASNS in tumor cells, is recognized as a prognostic biomarker, and l-asparaginase-based treatments (e.g., Asparlas) are frequently administered to these patients.

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Cryo-electron microscopy (cryo-EM) and cryo-electron tomography (cryo-ET) have revolutionized structural biology by enabling high-resolution imaging of biomolecules and cellular structures. However, traditional sample carriers, such as copper grids with carbon films, presented limitations, particularly in cryo-ET workflows. Issues like uneven cell distribution, beam-induced motion, and suboptimal vitrification can compromise data quality.

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Evaluating tissue distribution of Positron Emission Tomography (PET) tracers during their development conventionally involves autoradiography techniques, where radioactive compounds are used for visualization and quantification in tissues during preclinical development stages. Mass Spectrometry Imaging (MSI) offers a potential alternative, providing spatial information without the need for radioactivity with a similar spatial resolution. This study aimed to optimize a MSI sample preparation protocol for assessing PET tracer candidates with a focus on two compounds: UCB-J and UCB2400.

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Glioblastoma multiforme (GBM) is a highly aggressive brain cancer with a median survival of 15 months. Despite advancements in conventional treatment approaches such as surgery and chemotherapy, the prognosis remains poor. This study investigates the use of rapid evaporative ionization mass spectrometry (REIMS) for real-time overall survival time classification of GBM samples and uses matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) to compare lipidomic differences within GBM tumors.

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In recent years, mass spectrometry-based imaging techniques have improved at unprecedented speeds, particularly in spatial resolution, and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) experiments can now routinely image molecular profiles of single cells in an untargeted fashion. With the introduction of MALDI-immunohistochemistry (IHC), multiplexed visualization of targeted proteins in their native tissue location has become accessible and joins the suite of multimodal imaging techniques that help unravel molecular complexities. However, MALDI-IHC has not been validated for use with cell cultures at single-cell level.

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Microplastics (MPs) are continuously found in soil and water environments. Within aquatic ecosystems, filter-feeding organisms are unable to discriminate MPs from food particles while fish may intentionally ingest MPs by mistaking them for prey. In both cases, MPs can accumulate in tissues with subsequent implications for human and environmental health.

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Drug toxicity during the development of candidate pharmaceuticals is the leading cause of discontinuation in preclinical drug discovery and development. Traditionally, the cause of the toxicity is often determined by histological examination, clinical pathology, and the detection of drugs and/or metabolites by liquid chromatography-mass spectrometry (LC-MS). While these techniques individually provide information on the pathological effects of the drug and the detection of metabolites, they cannot provide specific molecular spatial information without additional experiments.

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Biobased poly(ethylene furanoate) (PEF)/poly(ε-caprolactone) (PCL) block copolymers have been synthesized using ring opening polymerization (ROP) of ε-caprolactone (ε-CL) in the presence of PEF in different mass ratios. An increase in intrinsic viscosity is observed for the block copolymers with higher ε-CL content due to the extension of their macromolecular chain. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MS) was employed to understand the composition and structure of the produced block copolymers.

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In the field of cultural heritage, and more specifically in oil paintings, the ability to unambiguously identify and locate metal soaps is of great interest for a better understanding of painting degradation. Here, we demonstrate the use of a Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) instrument capable of tandem mass spectrometry imaging for the unambiguous identification and localization of lead soaps in cross sections of samples of old oil paintings at high spatial resolution. It is shown that the specific fragmentation pattern of lead soaps is dictated by the loss of the lead ion and that fragmentation occurs on the hydrocarbon chains of the fatty acids.

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In the dynamic field of drug discovery and development, a comprehensive understanding of drug absorption, distribution, metabolism, excretion, and toxicity is crucial. Mass spectrometry imaging (MSI) has become a key analytical tool in the pharmaceutical industry, allowing evaluation of drug biodistribution and molecular profiles. Antisense oligonucleotides (ASOs) are emerging drug candidates for treating neurologic diseases.

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Mass spectrometry imaging (MSI) techniques enable the generation of molecular maps from complex and heterogeneous matrices. A burger patty, whether plant-based or meat-based, represents one such complex matrix where studying the spatial distribution of components can unveil crucial features relevant to the consumer experience or production process. Furthermore, the MSI data can aid in the classification of ingredients and composition.

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Objectives: Cartilage defects (CDs) are regarded as early manifestation of osteoarthritis (OA). The infrapatellar fat pad (IPFP) is an important mediator in maintaining joint homeostasis, disease progression and tissue repair, with a crucial role of its secreted proteins. Here, we investigate the proteome of the IPFP in relation to clinical status and response to surgical treatment of CDs.

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Mass spectrometry imaging (MSI) is a technique that analyzes the chemical information and spatial distribution of surface analytes. Most MSI studies are conducted in microprobe mode, in which a mass spectrum is collected for each pixel to create a mass image. Thus, the spatial resolution, sample imaging area, and imaging speed are linked.

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Mass spectrometry imaging (MSI) is constantly improving in spatial resolving power, throughput and mass resolution. Although beneficial, these improvements increase data set size and content. The larger data requires correspondingly fast computer-based analyses.

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Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) started with spatial mapping of peptides and proteins. Since then, numerous bottom-up protocols have been developed. However, achievable spatial resolution and sample preparation with many wet steps hindered the development of single cell-level workflows for bottom-up spatial proteomics.

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Photobiomodulation (PBM) therapy is the application of near-infrared (NIR) exposure to injuries or lesions to (among others) improve wound healing, reduce inflammation, and decreases acute and chronic pain. However, the understanding of the molecular mechanism of PBM, more specifically the effects of NIR on skin cells is still lacking behind. Lipids are essential components of cellular membranes that are integral to skin structure and function.

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Microplastic pollution poses a significant environmental threat due to its persistence, widespread distribution, and inherent toxic potential. Despite the increasing number of publications in this field, a standardized protocol for the laboratory intake of microplastics by has yet to be established. In this study, we introduce a verified protocol designed to facilitate the ingestion of microplastic particles (MPs) by , ranging in size from 5-55 µm.

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Background: While REIMS technology has successfully been demonstrated for the histological identification of ex-vivo breast tumor tissues, questions regarding the robustness of the approach and the possibility of tumor molecular diagnostics still remain unanswered. In the current study, we set out to determine whether it is possible to acquire cross-comparable REIMS datasets at multiple sites for the identification of breast tumors and subtypes.

Methods: A consortium of four sites with three of them having access to fresh surgical tissue samples performed tissue analysis using identical REIMS setups and protocols.

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Plant health, which affects the nutritional quality and safety of derivative food products, is influenced by symbiotic interactions with microorganisms. These interactions influence the local molecular profile at the tissue level. Therefore, studying the distribution of molecules within plants, microbes, and plant-based food is crucial to assess plant health, ensure the safety and quality of the agricultural products that become part of our food supply, and plan agricultural management practices.

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Rationale: Matrix-assisted laser desorption/ionisation-mass spectrometry imaging (MALDI-MSI) is a powerful label-free technique for biomolecule detection (e.g., lipids), within tissue sections across various biological species.

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Aquatic ferns of the genus Azolla (Azolla) form highly productive symbioses with filamentous cyanobacteria fixing N in their leaf cavities, Nostoc azollae. Stressed symbioses characteristically turn red due to 3-deoxyanthocyanidin (DA) accumulation, rare in angiosperms and of unknown function. To understand DA accumulation upon cold acclimation and recovery, we integrated laser-desorption-ionization mass-spectrometry-imaging (LDI-MSI), a new Azolla filiculoides genome-assembly and annotation, and dual RNA-sequencing into phenotypic analyses of the symbioses.

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Background: Cancer cachexia is a multifactorial metabolic syndrome characterized by systemic inflammation and ongoing skeletal muscle loss resulting in weakness, poor quality of life, and decreased survival. Whereas lipid accumulation in skeletal muscle is associated with cancer cachexia as well as the prognosis of cancer patients, surprisingly little is known about the nature of the lipids that accumulate in the muscle during cachexia, and whether this is related to inflammation. We aimed to identify the types and distributions of intramyocellular lipids in patients with and without cancer cachexia.

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