| 1. |
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| 2. |
- Hulme, Heather E., et al.
(författare)
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Mass spectrometry imaging identifies palmitoylcarnitine as an immunological mediator during Salmonella Typhimurium infection
- 2017
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Salmonella Typhimurium causes a self-limiting gastroenteritis that may lead to systemic disease. Bacteria invade the small intestine, crossing the intestinal epithelium from where they are transported to the mesenteric lymph nodes (MLNs) within migrating immune cells. MLNs are an important site at which the innate and adaptive immune responses converge but their architecture and function is severely disrupted during S. Typhimurium infection. To further understand host-pathogen interactions at this site, we used mass spectrometry imaging (MSI) to analyse MLN tissue from a murine model of S. Typhimurium infection. A molecule, identified as palmitoylcarnitine (PalC), was of particular interest due to its high abundance at loci of S. Typhimurium infection and MLN disruption. High levels of PalC localised to sites within the MLNs where B and T cells were absent and where the perimeter of CD169(+) sub capsular sinus macrophages was disrupted. MLN cells cultured ex vivo and treated with PalC had reduced CD4(+) CD25(+) T cells and an increased number of B220(+) CD19(+) B cells. The reduction in CD4(+) CD25(+) T cells was likely due to apoptosis driven by increased caspase-3/7 activity. These data indicate that PalC significantly alters the host response in the MLNs, acting as a decisive factor in infection outcome.
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| 3. |
- Nilsson, Anna, et al.
(författare)
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Investigating Nephrotoxicity of Polymyxin Derivatives by Mapping Renal Distribution Using Mass Spectrometry Imaging
- 2015
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Ingår i: Chemical Research in Toxicology. - : American Chemical Society (ACS). - 0893-228X .- 1520-5010. ; 28:9, s. 1823-1830
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Tidskriftsartikel (refereegranskat)abstract
- Colistin and polymyxin B are effective treatment options for Gram-negative resistant bacteria but are used as last-line therapy due to their dose-limiting nephrotoxicity. A critical factor in developing safer polymyxin analogues is understanding accumulation of the drugs and their metabolites, which is currently limited due to the lack of effective techniques for analysis of these challenging molecules. Mass spectrometry imaging (MSI) allows direct detection of targets (drugs, metabolites, and endogenous compounds) from tissue sections. The presented study exemplifies the utility of MSI by measuring the distribution of polymyxin B1, colistin, and polymyxin B nonapeptide (PMBN) within dosed rat kidney tissue sections. The label-free MSI analysis revealed that the nephrotoxic compounds (polymyxin B1 and colistin) preferentially accumulated in the renal cortical region. The less nephrotoxic analogue, polymyxin B nonapeptide, was more uniformly distributed throughout the kidney. In addition, metabolites of the dosed compounds were detected by MSI. Kidney homogenates were analyzed using LC/MS/MS to determine total drug exposure and for metabolite identification. To our knowledge, this is the first time such techniques have been utilized to measure the distribution of polymyxin drugs and their metabolites. By simultaneously detecting the distribution of drug and drug metabolites, MSI offers a powerful alternative to tissue homogenization analysis and label or antibody-based imaging.
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| 4. |
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| 5. |
- Ashton, Susan, et al.
(författare)
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Aurora kinase inhibitor nanoparticles target tumors with favorable therapeutic index in vivo
- 2016
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Ingår i: Science Translational Medicine. - : American Association for the Advancement of Science (AAAS). - 1946-6234 .- 1946-6242. ; 8:325
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Tidskriftsartikel (refereegranskat)abstract
- Efforts to apply nanotechnology in cancer have focused almost exclusively on the delivery of cytotoxic drugs to improve therapeutic index. There has been little consideration of molecularly targeted agents, in particular kinase inhibitors, which can also present considerable therapeutic index limitations. We describe the development of Accurin polymeric nanoparticles that encapsulate the clinical candidate AZD2811, an Aurora B kinase inhibitor, using an ion pairing approach. Accurins increase biodistribution to tumor sites and provide extended release of encapsulated drug payloads. AZD2811 nanoparticles containing pharmaceutically acceptable organic acids as ion pairing agents displayed continuous drug release for more than 1 week in vitro and a corresponding extended pharmacodynamic reduction of tumor phosphorylated histone H3 levels in vivo for up to 96 hours after a single administration. A specific AZD2811 nanoparticle formulation profile showed accumulation and retention in tumors with minimal impact on bone marrow pathology, and resulted in lower toxicity and increased efficacy in multiple tumor models at half the dose intensity of AZD1152, a water-soluble prodrug of AZD2811. These studies demonstrate that AZD2811 can be formulated in nanoparticles using ion pairing agents to give improved efficacy and tolerability in preclinical models with less frequent dosing. Accurins specifically, and nanotechnology in general, can increase the therapeutic index of molecularly targeted agents, including kinase inhibitors targeting cell cycle and oncogenic signal transduction pathways, which have to date proved toxic in humans.
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| 6. |
- Bäckström, Erica, et al.
(författare)
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Uncovering the regional localization of inhaled salmeterol retention in the lung
- 2018
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Ingår i: Drug Delivery. - : Taylor & Francis Group. - 1071-7544 .- 1521-0464. ; 25:1, s. 838-845
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Tidskriftsartikel (refereegranskat)abstract
- Treatment of respiratory disease with a drug delivered via inhalation is generally held as being beneficial as it provides direct access to the lung target site with a minimum systemic exposure. There is however only limited information of the regional localization of drug retention following inhalation. The aim of this study was to investigate the regional and histological localization of salmeterol retention in the lungs after inhalation and to compare it to systemic administration. Lung distribution of salmeterol delivered to rats via nebulization or intravenous (IV) injection was analyzed with high-resolution mass spectrometry imaging (MSI). Salmeterol was widely distributed in the entire section at 5 min after inhalation, by 15 min it was preferentially retained in bronchial tissue. Via a novel dual-isotope study, where salmeterol was delivered via inhalation and d(3)-salmeterol via IV to the same rat, could the effective gain in drug concentration associated with inhaled delivery relative to IV, expressed as a site-specific lung targeting factor, was 5-, 31-, and 45-fold for the alveolar region, bronchial sub-epithelium and epithelium, respectively. We anticipate that this MSI-based framework for quantifying regional and histological lung targeting by inhalation will accelerate discovery and development of local and more precise treatments of respiratory disease.
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| 7. |
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| 8. |
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| 9. |
- Goodwin, Richard J. A., et al.
(författare)
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Conductive carbon tape used for support and mounting of both whole animal and fragile heat-treated tissue sections for MALDI MS imaging and quantitation
- 2012
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Ingår i: Journal of Proteomics. - : Elsevier BV. - 1874-3919 .- 1876-7737. ; 75:16, s. 4912-4920
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Tidskriftsartikel (refereegranskat)abstract
- Analysis of whole animal tissue sections by MALDI MS imaging (MSI) requires effective sample collection and transfer methods to allow the highest quality of in situ analysis of small or hard to dissect tissues. We report on the use of double-sided adhesive conductive carbon tape during whole adult rat tissue sectioning of carboxymethyl cellulose (CMC) embedded animals, with samples mounted onto large format conductive glass and conductive plastic MALDI targets, enabling MSI analysis to be performed on both TOF and FT-ICR MALDI mass spectrometers. We show that mounting does not unduly affect small molecule MSI detection by analyzing tiotropium abundance and distribution in rat lung tissues, with direct on-tissue quantitation achieved. Significantly, we use the adhesive tape to provide support to embedded delicate heat-stabilized tissues, enabling sectioning and mounting to be performed that maintained tissue integrity on samples that had previously been impossible to adequately prepare section for MSI analysis. The mapping of larger peptidomic molecules was not hindered by tape mounting samples and we demonstrate this by mapping the distribution of PEP-19 in both native and heat-stabilized rat brains. Furthermore, we show that without heat stabilization PEP-19 degradation fragments can detected and identified directly by MALDI MSI analysis.This article is part of a Special Issue entitled: Imaging Mass Spectrometry: A User's Guide to a New Technique for Biological and Biomedical Research.
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| 10. |
- Goodwin, Richard J. A., et al.
(författare)
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Exemplifying the Screening Power of Mass Spectrometry Imaging over Label-Based Technologies for Simultaneous Monitoring of Drug and Metabolite Distributions in Tissue Sections
- 2016
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Ingår i: Journal of Biomolecular Screening. - : Elsevier BV. - 1087-0571 .- 1552-454X. ; 21:2, s. 187-193
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Tidskriftsartikel (refereegranskat)abstract
- Mass spectrometry imaging (MSI) provides pharmaceutical researchers with a suite of technologies to screen and assess compound distributions and relative abundances directly from tissue sections and offer insight into drug discovery-applicable queries such as blood-brain barrier access, tumor penetration/retention, and compound toxicity related to drug retention in specific organs/cell types. Label-free MSI offers advantages over label-based assays, such as quantitative whole-body autoradiography (QWBA), in the ability to simultaneously differentiate and monitor both drug and drug metabolites. Such discrimination is not possible by label-based assays if a drug metabolite still contains the radiolabel. Here, we present data exemplifying the advantages of MSI analysis. Data of the distribution of AZD2820, a therapeutic cyclic peptide, are related to corresponding QWBA data. Distribution of AZD2820 and two metabolites is achieved by MSI, which [C-14] AZD2820 QWBA fails to differentiate. Furthermore, the high mass-resolving power of Fourier transform ion cyclotron resonance MS is used to separate closely associated ions.
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| 11. |
- Goodwin, Richard J A, et al.
(författare)
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Qualitative and Quantitative MALDI Imaging of the Positron Emission Tomography Ligands Raclopride (a D2 Dopamine Antagonist) and SCH 23390 (a D1 Dopamine Antagonist) in Rat Brain Tissue Sections Using a Solvent-Free Dry Matrix Application Method
- 2011
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 83:24, s. 9694-9701
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Tidskriftsartikel (refereegranskat)abstract
- The distributions of positron emission tomography (PET) ligands in rat brain tissue sections were analyzed by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI). The detection of the PET ligands was possible following the use of a solvent-free dry MALDI matrix application method employing finely ground dry α-cyano-4-hydroxycinnamic acid (CHCA). The D2 dopamine receptor antagonist 3,5-dichloro-N-{[(2S)-1-ethylpyrrolidin-2-yl]methyl}-2-hydroxy-6-methoxybenzamide (raclopride) and the D1 dopamine receptor antagonist 7-chloro-3-methyl-1-phenyl-1,2,4,5-tetrahydro-3-benzazepin-8-ol (SCH 23390) were both detected at decreasing abundance at increasing period postdosing. Confirmation of the compound identifications and distributions was achieved by a combination of mass-to-charge ratio accurate mass, isotope distribution, and MS/MS fragmentation imaging directly from tissue sections (performed using MALDI TOF/TOF, MALDI q-TOF, and 12T MALDI-FT-ICR mass spectrometers). Quantitative data was obtained by comparing signal abundances from tissues to those obtained from quantitation control spots of the target compound applied to adjacent vehicle control tissue sections (analyzed during the same experiment). Following a single intravenous dose of raclopride (7.5 mg/kg), an average tissue concentration of approximately 60 nM was detected compared to 15 nM when the drug was dosed at 2 mg/kg, indicating a linear response between dose and detected abundance. SCH 23390 was established to have an average tissue concentration of approximately 15 μM following a single intravenous dose at 5 mg/kg. Both target compounds were also detected in kidney tissue sections when employing the same MSI methodology. This study illustrates that a MSI may well be readily applied to PET ligand research development when using a solvent-free dry matrix coating.
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| 12. |
- Goodwin, Richard J. A.
(författare)
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Sample preparation for mass spectrometry imaging : Small mistakes can lead to big consequences
- 2012
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Ingår i: Journal of Proteomics. - : Elsevier BV. - 1874-3919 .- 1876-7737. ; 75:16, s. 4893-4911
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Forskningsöversikt (refereegranskat)abstract
- Mass spectrometry imaging (MSI) enables the direct analysis of molecules from the surface of a wide variety of samples, allowing the multiplex measurement of both abundance and distribution of small molecules, lipids, peptides and proteins. As the technology has been refined an increasing number of ionization methods and mass analyzers has been used that enable increased spatial and spectral resolution measurements to be made at an increased speed. Alongside the instrumentation improvements there has been optimization of sample preparation procedures that allow the highest quality data to be obtained, reproducibly, from an ever increasing diversity of samples. This review will consider the development and standardization of sample preparation methods applicable to MSI, describing the stages and procedures undertaken from the instance of sample collection, through storage, preparation and on through final processing prior to analysis. Recent technical advancements will be highlighted and areas where further experimentation and optimization may well be required will be described. All aspects of the sample preparation pipeline will be considered in detail, with examples from the literature used to emphasize why rigorous sample preparation for MSI is vital to achieve the most accurate, reproducible and validated MSI data possible. This article is part of a Special Issue entitled: Imaging Mass Spectrometry: A User's Guide to a New Technique for Biological and Biomedical Research.
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| 13. |
- Goodwin, Richard JA, et al.
(författare)
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The significance of ambient-temperature on pharmaceutical and endogenous compound abundance and distribution in tissues sections when analyzed by matrix-assisted laser desorption/ionization mass spectrometry imaging
- 2012
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Ingår i: Rapid Communications in Mass Spectrometry. - : Wiley. - 0951-4198 .- 1097-0231. ; 26:5, s. 494-498
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Tidskriftsartikel (refereegranskat)abstract
- RATIONALE: Mass spectrometry imaging has proven to be a complementary assay to the traditional labeled-compound studies employed in drug research and development. However, there has been limited examination of the technical limitations of the technique with respect to small molecule stability in samples. METHODS: Raclopride dosed rat brain tissue sections (single dose i.v. 2 mg/kg) were allowed to warm to room temperature for 0 to 5 min prior to either a solvent-based wet matrix-assisted laser desorption/ionization (MALDI) matrix or a solvent-free dry MALDI matrix being applied. Subsequent MS imaging analysis was at a spatial resolution of 200 mm, performed using a MALDI TOF/TOF (Ultraflex II, Bruker Daltonics). RESULTS: MALDI-MS has been used to monitor the time-dependent appearance and loss of small molecule abundance in tissue sections brought rapidly to room temperature for short periods of time. The abundances of a range of markers were seen to vary across the time course, both increasing and decreasing. The intensity of some markers changed significantly within 1 min. Importantly, the abundance of raclopride was seen to decrease over the 5-min time period examined. CONCLUSIONS: The results strongly indicate that considerable care is required to allow comparison of both pharmaceutical and endogenous compounds between MALDI-MSI experiments and also has implications for the standard practice of thaw-mounting multiple tissue sections onto MALDI-MS targets during MSI experiments.
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| 14. |
- Hamm, Gregory R., et al.
(författare)
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Revealing the Regional Localization and Differential Lung Retention of Inhaled Compounds by Mass Spectrometry Imaging
- 2020
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Ingår i: Journal of Aerosol Medicine. - : Mary Ann Liebert Inc. - 1941-2711 .- 1941-2703. ; 33:1, s. 43-53
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Tidskriftsartikel (refereegranskat)abstract
- Background: For the treatment of respiratory disease, inhaled drug delivery aims to provide direct access to pharmacological target sites while minimizing systemic exposure. Despite this long-held tenet of inhaled therapeutic advantage, there are limited data of regional drug localization in the lungs after inhalation. The aim of this study was to investigate the distribution and retention of different chemotypes typifying available inhaled drugs [slowly dissolving neutral fluticasone propionate (FP) and soluble bases salmeterol and salbutamol] using mass spectrometry imaging (MSI).Methods: Salmeterol, salbutamol, and FP were simultaneously delivered by inhaled nebulization to rats. In the same animals, salmeterol-d(3), salbutamol-d(3), and FP-d(3) were delivered by intravenous (IV) injection. Samples of lung tissue were obtained at 2- and 30-minute postdosing, and high-resolution MSI was used to study drug distribution and retention.Results: IV delivery resulted in homogeneous lung distribution for all molecules. In comparison, while inhalation also gave rise to drug presence in the entire lung, there were regional chemotype-dependent areas of higher abundance. At the 30-minute time point, inhaled salmeterol and salbutamol were preferentially retained in bronchiolar tissue, whereas FP was retained in all regions of the lungs.Conclusion: This study clearly demonstrates that inhaled small molecule chemotypes are differentially distributed in lung tissue after inhalation, and that high-resolution MSI can be applied to study these retention patterns.
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| 15. |
- Kouwenhoven, M. B. N., et al.
(författare)
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The formation of very wide binaries during the star cluster dissolution phase
- 2010
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 1365-2966 .- 0035-8711. ; 404:4, s. 1835-1848
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Forskningsöversikt (refereegranskat)abstract
- Over the past few decades, numerous wide (> 103 au) binaries in the Galactic field and halo have been discovered. Their existence cannot be explained by the process of star formation or by dynamical interactions in the field, and their origin has long been a mystery. We explain the origin of these wide binaries by formation during the dissolution phase of young star clusters: an initially unbound pair of stars may form a binary when their distance in phase space is small. Using N-body simulations, we find that the resulting wide binary fraction in the semimajor axis range 103 au < a < 0.1 pc for individual clusters is 1-30 per cent, depending on the initial conditions. The existence of numerous wide binaries in the field is consistent with observational evidence that most clusters start out with a large degree of substructure. The wide binary fraction decreases strongly with increasing cluster mass, and the semimajor axis of the newly formed binaries is determined by the initial cluster size. The resulting eccentricity distribution is thermal, and the mass ratio distribution is consistent with gravitationally focused random pairing. As a large fraction of the stars forms in primordial binaries, we predict that a large number of the observed 'wide binaries' are in fact triple or quadruple systems. By integrating over the initial cluster mass distribution, we predict a binary fraction of a few per cent in the semimajor axis range 103 au < a < 0.1 pc in the Galactic field, which is smaller than the observed wide binary fraction. However, this discrepancy may be solved when we consider a broad range of cluster morphologies.
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| 16. |
- Nilsson, Anna, et al.
(författare)
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Mass Spectrometry Imaging in Drug Development
- 2015
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 87:3, s. 1437-1455
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Forskningsöversikt (refereegranskat)
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| 17. |
- Nilsson, Anna, et al.
(författare)
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Mass Spectrometry Imaging proves differential absorption profiles of well-characterised permeability markers along the crypt-villus axis
- 2017
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge about the region-specific absorption profiles from the gastrointestinal tract of orally administered drugs is a critical factor guiding dosage form selection in drug development. We have used a novel approach to study three well-characterized permeability and absorption marker drugs in the intestine. Propranolol and metoprolol (highly permeable compounds) and atenolol (low-moderate permeability compound) were orally co-administered to rats. The site of drug absorption was revealed by high spatial resolution matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) and complemented by quantitative measurement of drug concentration in tissue homogenates. MALDI-MSI identified endogenous molecular markers that illustrated the villi structures and confirmed the different absorption sites assigned to histological landmarks for the three drugs. Propranolol and metoprolol showed a rapid absorption and shorter transit distance in contrast to atenolol, which was absorbed more slowly from more distal sites. This study provides novel insights into site specific absorption for each of the compounds along the crypt-villus axis, as well as confirming a proximal-distal absorption gradient along the intestine. The combined analytical approach allowed the quantification and spatial resolution of drug distribution in the intestine and provided experimental evidence for the suggested absorption behaviour of low and highly permeable compounds.
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| 18. |
- Shariatgorji, Mohammadreza, et al.
(författare)
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Bromopyrylium Derivatization Facilitates Identification by Mass Spectrometry Imaging of Monoamine Neurotransmitters and Small Molecule Neuroactive Compounds
- 2020
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Ingår i: Journal of the American Society for Mass Spectrometry. - : AMER CHEMICAL SOC. - 1044-0305 .- 1879-1123. ; 31:12, s. 2553-2557
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Tidskriftsartikel (refereegranskat)abstract
- Mass spectrometry imaging using matrix-assisted laser desorption/ionization and desorption electrospray ionization has recently been employed to investigate the distribution of neurotransmitters, including biogenic amines and amino acids, directly in brain tissue sections. Ionization is facilitated by charge-tagging through pyrylium derivatization of primary amine containing neurotransmitters directly in tissue sections, significantly improving the limit of detection. Since the derivatization adds carbon and hydrogen to the target compounds, the resulting isotopic patterns of the products are not distinctive from those of the nonderivatized species. Here, we describe an approach for chemically modifying the reactive pyrylium ion to introduce the distinct isotopic signature of bromine in mass spectra of chemically derivatized substances in tissue sections. The method enables monoamine compounds to be distinguished directly in tissue sections, facilitating their identification.
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| 19. |
- Shariatgorji, Mohammadreza, et al.
(författare)
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Controlled-pH Tissue Cleanup Protocol for Signal Enhancement of Small Molecule Drugs Analyzed by MALDI-MS Imaging
- 2012
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 1520-6882 .- 0003-2700. ; 84:10, s. 4603-4607
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Tidskriftsartikel (refereegranskat)abstract
- The limit of detection of low-molecular weight compounds in tissue sections, analyzed by matrix assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI), was significantly improved by employing sample washing using a pH-controlled buffer solution. The pH of the washing solutions were set at values whereby the target analytes would have low solubility. Washing the tissue sections in the buffered solution resulted in removal of endogenous soluble ionization-suppressing compounds and salts, while the target compound remained in situ with minor or no delocalization during the buffered washing procedure. Two pharmaceutical compounds (cimetidine and imipramine) and one new protease inhibitor compound were successfully used to evaluate the feasibility of the pH-controlled tissue washing protocol for MALDI-MSI. Enhancement in signal-to-noise ratio was achieved by a factor of up to 10.
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| 20. |
- Shariatgorji, Mohammadreza, et al.
(författare)
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Deuterated Matrix-Assisted Laser Desorption Ionization Matrix Uncovers Masked Mass Spectrometry Imaging Signals of Small Molecules
- 2012
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 84:16, s. 7152-7157
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Tidskriftsartikel (refereegranskat)abstract
- D-4-alpha-Cyano-4-hydroxycinnamic acid (D-4-CHCA) has been synthesized for use as a matrix for matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) and MALDI-MS imaging (MSI) of small molecule drugs and endogenous compounds. MALDI-MS analysis of small molecules has historically been hindered by interference from matrix ion clusters and fragment peaks that mask signals of low molecular weight compounds of interest. By using D-4-CHCA, the cluster and fragment peaks of CHCA, the most common matrix for analysis of small molecules, are shifted by + 4, + 8 and + 12 Da, which expose signals across areas of the previously concealed low mass range. Here, obscured MALDI-MS signals of a synthetic small molecule pharmaceutical, a naturally occurring isoquinoline alkaloid, and endogenous compounds including the neurotransmitter acetylcholine have been unmasked and imaged directly from biological tissue sections.
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| 21. |
- Shariatgorji, Mohammadreza, et al.
(författare)
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Direct targeted quantitative molecular imaging of neurotransmitters in brain tissue sections
- 2014
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Ingår i: Neuron. - : Elsevier BV. - 0896-6273 .- 1097-4199. ; 84:4, s. 697-707
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Tidskriftsartikel (refereegranskat)abstract
- Current neuroimaging techniques have very limited abilities to directly identify and quantify neurotransmitters from brain sections. We have developed a molecular-specific approach for the simultaneous imaging and quantitation of multiple neurotransmitters, precursors, and metabolites, such as tyrosine, tryptamine, tyramine, phenethylamine, dopamine, 3-methoxytyramine, serotonin, GABA, glutamate, acetylcholine, and L-alpha-glycerylphosphorylcholine, in histological tissue sections at high spatial resolutions. The method is employed to directly measure changes in the absolute and relative levels ofneurotransmitters in specific brain structures in animal disease models and in response to drug treatments, demonstrating the power of mass spectrometry imaging in neuroscience.
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| 22. |
- Shariatgorji, Mohammadreza, et al.
(författare)
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Simultaneous imaging of multiple neurotransmitters and neuroactive substances in the brain by desorption electrospray ionization mass spectrometry
- 2016
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 136, s. 129-138
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Tidskriftsartikel (refereegranskat)abstract
- With neurological processes involving multiple neurotransmitters and neuromodulators, it is important to have the ability to directly map and quantify multiple signaling molecules simultaneously in a single analysis. By utilizing a molecular-specific approach, namely desorption electrospray ionization mass spectrometry imaging (DESI-MSI), we demonstrated that the technique can be used to image multiple neurotransmitters and their metabolites (dopamine, dihydroxyphenylacetic acid, 3-methoxytyramine, serotonin, glutamate, glutamine, aspartate,gamma-aminobutyric acid, adenosine) as well as neuroactive drugs (amphetamine, sibutramine, fluvoxamine) and drug metabolites in situ directly in brain tissue sections. The use of both positive and negative ionization modes increased the number of identified molecular targets. Chemical derivatization by charge-tagging the primary amines of molecules significantly increased the sensitivity, enabling the detection of low abundant neurotransmitters and other neuroactive substances previously undetectable by MSI. The sensitivity of the imaging approach of neurochemicals has a great potential in many diverse applications in fields such as neuroscience, pharmacology, drug discovery, neurochemistry, and medicine.
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| 23. |
- Shariatgorji, Reza, et al.
(författare)
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Spatial visualization of comprehensive brain neurotransmitter systems and neuroactive substances by selective in situ chemical derivatization mass spectrometry imaging
- 2021
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Ingår i: Nature Protocols. - : Springer Nature. - 1754-2189 .- 1750-2799. ; 16:7, s. 3298-3321
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Tidskriftsartikel (refereegranskat)abstract
- Molecule-specific techniques such as MALDI and desorption electrospray ionization mass spectrometry imaging enable direct and simultaneous mapping of biomolecules in tissue sections in a single experiment. However, neurotransmitter imaging in the complex environment of biological samples remains challenging. Our covalent charge-tagging approach using on-tissue chemical derivatization of primary and secondary amines and phenolic hydroxyls enables comprehensive mapping of neurotransmitter networks. Here, we present robust and easy-to-use chemical derivatization protocols that facilitate quantitative and simultaneous molecular imaging of complete neurotransmitter systems and drugs in diverse biological tissue sections with high lateral resolution. This is currently not possible with any other imaging technique. The protocol, using fluoromethylpyridinium and pyrylium reagents, describes all steps from tissue preparation (-1 h), chemical derivatization (1-2 h), data collection (timing depends on the number of samples and lateral resolution) and data analysis and interpretation. The specificity of the chemical reaction can also help users identify unknown chemical identities. Our protocol can reveal the cellular locations in which signaling molecules act and thus shed light on the complex responses that occur after the administration of drugs or during the course of a disease.
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| 24. |
- Strittmatter, Nicole, et al.
(författare)
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Holistic Characterization of a Salmonella Typhimurium Infection Model Using Integrated Molecular Imaging
- 2021
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Ingår i: Journal of the American Society for Mass Spectrometry. - : American Chemical Society (ACS). - 1044-0305 .- 1879-1123. ; 32:12, s. 2791-2802
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Tidskriftsartikel (refereegranskat)abstract
- A more complete and holistic view on host-microbe interactions is needed to understand the physiological and cellular barriers that affect the efficacy of drug treatments and allow the discovery and development of new therapeutics. Here, we developed a multimodal imaging approach combining histopathology with mass spectrometry imaging (MSI) and same section imaging mass cytometry (IMC) to study the effects of Salmonella Typhimurium infection in the liver of a mouse model using the S. Typhimurium strains SL3261 and SL1344. This approach enables correlation of tissue morphology and specific cell phenotypes with molecular images of tissue metabolism. IMC revealed a marked increase in immune cell markers and localization in immune aggregates in infected tissues. A correlative computational method (network analysis) was deployed to find metabolic features associated with infection and revealed metabolic clusters of acetyl carnitines, as well as phosphatidylcholine and phosphatidylethanolamine plasmalogen species, which could be associated with pro-inflammatory immune cell types. By developing an IMC marker for the detection of Salmonella LPS, we were further able to identify and characterize those cell types which contained S. Typhimurium.
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| 25. |
- Strittmatter, Nicole, et al.
(författare)
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Method To Visualize the Intratumor Distribution and Impact of Gemcitabine in Pancreatic Ductal Adenocarcinoma by Multimodal Imaging
- 2022
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 94:3, s. 1795-1803
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Tidskriftsartikel (refereegranskat)abstract
- Gemcitabine (dFdC) is a common treatment for pancreatic cancer; however, it is thought that treatment may fail because tumor stroma prevents drug distribution to tumor cells. Gemcitabine is a pro-drug with active metabolites generated intracellularly; therefore, visualizing the distribution of parent drug as well as its metabolites is important. A multimodal imaging approach was developed using spatially coregistered mass spectrometry imaging (MSI), imaging mass cytometry (IMC), multiplex immunofluorescence microscopy (mIF), and hematoxylin and eosin (H&E) staining to assess the local distribution and metabolism of gemcitabine in tumors from a genetically engineered mouse model of pancreatic cancer (KPC) allowing for comparisons between effects in the tumor tissue and its microenvironment. Mass spectrometry imaging (MSI) enabled the visualization of the distribution of gemcitabine (100 mg/kg), its phosphorylated metabolites dFdCMP, dFdCDP and dFdCTP, and the inactive metabolite dFdU. Distribution was compared to small-molecule ATR inhibitor AZD6738 (25 mg/kg), which was codosed. Gemcitabine metabolites showed heterogeneous distribution within the tumor, which was different from the parent compound. The highest abundance of dFdCMP, dFdCDP, and dFdCTP correlated with distribution of endogenous AMP, ADP, and ATP in viable tumor cell regions, showing that gemcitabine active metabolites are reaching the tumor cell compartment, while AZD6738 was located to nonviable tumor regions. The method revealed that the generation of active, phosphorylated dFdC metabolites as well as treatment-induced DNA damage primarily correlated with sites of high proliferation in KPC PDAC tumor tissue, rather than sites of high parent drug abundance.
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| 26. |
- Swales, John G., et al.
(författare)
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Mass Spectrometry Imaging of Cassette-Dosed Drugs for Higher Throughput Pharmacokinetic and Biodistribution Analysis
- 2014
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 86:16, s. 8473-8480
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Tidskriftsartikel (refereegranskat)abstract
- Cassette dosing of compounds for preclinical drug plasma pharmacokinetic analysis has been shown to be a powerful strategy within the pharmaceutical industry for increasing throughput while decreasing the number of animals used. Presented here for the first time is data on the application of a cassette dosing strategy for label-free tissue distribution studies. The aim of the study was to image the spatial distribution of eight nonproprietary drugs (haloperidol, bufuralol, midazolam, clozapine, terfenadine, erlotinib, olanzapine, and moxifloxacin) in multiple tissues after oral and intravenous cassette dosing (four compounds per dose route). An array of mass spectrometry imaging technologies, including matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI MSI), liquid extraction surface analysis tandem mass spectrometry (LESA-MS/MS), and desorption electrospray ionization mass spectrometry (DESI-MS) was used. Tissue analysis following intravenous and oral administration of discretely and cassette-dosed compounds demonstrated similar relative abundances across a range of tissues indicating that a cassette dosing approach was applicable. MALDI MSI was unsuccessful in detecting all of the target compounds; therefore, DESI MSL a complementary mass spectrometry imaging technique, was used to detect additional target compounds. In addition, by adapting technology used for tissue profiling (LESA-MS/MS) low spatial resolution mass spectrometry imaging (similar to 1 mm) was possible for all targets across all tissues. This study exemplifies the power of multiplatform MSI analysis within a pharmaceutical research and development (R&D) environment. Furthermore, we have illustrated that the cassette dosing approach can be readily applied to provide combined, label-free pharmacokinetic and drug distribution data at an early stage of the drug discovery/development process while minimizing animal usage.
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| 27. |
- Swales, John G., et al.
(författare)
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Quantitation of Endogenous Metabolites in Mouse Tumors Using Mass-Spectrometry Imaging
- 2018
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Ingår i: Analytical Chemistry. - : AMER CHEMICAL SOC. - 0003-2700 .- 1520-6882. ; 90:10, s. 6051-6058
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Tidskriftsartikel (refereegranskat)abstract
- Described is a quantitative-mass-spectrometry-imaging (qMSI) methodology for the analysis of lactate and glutamate distributions in order to delineate heterogeneity among mouse tumor models used to support drug-discovery efficacy testing. We evaluate and report on preanalysis-stabilization methods aimed at improving the reproducibility and efficiency of quantitative assessments of endogenous molecules in tissues. Stability experiments demonstrate that optimum stabilization protocols consist of frozen-tissue embedding, post-tissue-sectioning desiccation, and storage at -80 degrees C of tissue sections sealed in vacuum-tight containers. Optimized stabilization protocols are used in combination with qMSI methodology for the absolute quantitation of lactate and glutamate in tumors, incorporating the use of two different stable-isotope-labeled versions of each analyte and spectral-clustering performed on each tissue section using k-means clustering to allow region-specific, pixel-by-pixel quantitation. Region-specific qMSI was used to screen different tumor models and identify a phenotype that has low lactate heterogeneity, which will enable accurate measurements of lactate modulation in future drug-discovery studies. We conclude that using optimized qMSI protocols, it is possible to quantify endogenous metabolites within tumors, and region-specific quantitation can provide valuable insight into tissue heterogeneity and the tumor microenvironment.
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| 28. |
- Vallianatou, Theodosia, et al.
(författare)
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A mass spectrometry imaging approach for investigating how drug-drug interactions influence drug blood-brain barrier permeability
- 2018
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 172, s. 808-816
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Tidskriftsartikel (refereegranskat)abstract
- There is a high need to develop quantitative imaging methods capable of providing detailed brain localization information of several molecular species simultaneously. In addition, extensive information on the effect of the blood-brain barrier on the penetration, distribution and efficacy of neuroactive compounds is required. Thus, we have developed a mass spectrometry imaging method to visualize and quantify the brain distribution of drugs with varying blood-brain barrier permeability. With this approach, we were able to determine blood-brain barrier transport of different drugs and define the drug distribution in very small brain structures (e.g., choroid plexus) due to the high spatial resolution provided. Simultaneously, we investigated the effect of drug-drug interactions by inhibiting the membrane transporter multidrug resistance 1 protein. We propose that the described approach can serve as a valuable analytical tool during the development of neuroactive drugs, as it can provide physiologically relevant information often neglected by traditional imaging technologies.
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| 29. |
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| 30. |
- Wittenmark, Björn, et al.
(författare)
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Adaptive Decoupling of Multivariable Systems
- 1987
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Ingår i: International Journal of Control. - : Informa UK Limited. - 0020-7179 .- 1366-5820. ; 46:6, s. 1992-2009
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Tidskriftsartikel (refereegranskat)abstract
- For many industrial processes, it is of interest to design a decoupling precompensator. The precompensator makes it possible to design controllers based on single-input-single-output models of the process. A model of the process must be known to design the precompensator. This paper shows how the precompensator can be designed adaptively using input-output measurements. The precompensator is first designed for the case when the process is known. The adaptive precompensator is then constructed using the certainty equivalence principle. The convergence properties and the implementation of the adaptive decoupler are discussed. It is shown that the adaptive scheme will converge provided the system is persistently excited and that a suitable model structure is used in the estimation.
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