| 1. |
- Nilsson, Anna, et al.
(author)
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Fine Mapping the Spatial Distribution and Concentration of Unlabeled Drugs within Tissue Micro-Compartments Using Imaging Mass Spectrometry
- 2010
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In: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 5:7, s. e11411-
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Journal article (peer-reviewed)abstract
- Readouts that define the physiological distributions of drugs in tissues are an unmet challenge and at best imprecise, but are needed in order to understand both the pharmacokinetic and pharmacodynamic properties associated with efficacy. Here we demonstrate that it is feasible to follow the in vivo transport of unlabeled drugs within specific organ and tissue compartments on a platform that applies MALDI imaging mass spectrometry to tissue sections characterized with high definition histology. We have tracked and quantified the distribution of an inhaled reference compound, tiotropium, within the lungs of dosed rats, using systematic point by point MS and MS/MS sampling at 200 mu m intervals. By comparing drug ion distribution patterns in adjacent tissue sections, we observed that within 15 min following exposure, tiotropium parent MS ions (mass-to-charge; m/z 392.1) and fragmented daughter MS/MS ions (m/z 170.1 and 152.1) were dispersed in a concentration gradient (80 fmol-5 pmol) away from the central airways into the lung parenchyma and pleura. These drug levels agreed well with amounts detected in lung compartments by chemical extraction. Moreover, the simultaneous global definition of molecular ion signatures localized within 2-D tissue space provides accurate assignment of ion identities within histological landmarks, providing context to dynamic biological processes occurring at sites of drug presence. Our results highlight an important emerging technology allowing specific high resolution identification of unlabeled drugs at sites of in vivo uptake and retention.
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| 2. |
- Soehnlein, Oliver, et al.
(author)
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Neutrophil primary granule proteins HBP and HNP1-3 boost bacterial phagocytosis by human and murine macrophages.
- 2008
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In: Journal of Clinical Investigation. - 0021-9738. ; 118:10, s. 3491-3502
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Journal article (peer-reviewed)abstract
- In acute inflammation, infiltrating polymorphonuclear leukocytes (also known as PMNs) release preformed granule proteins having multitudinous effects on the surrounding environment. Here we present what we believe to be a novel role for PMN-derived proteins in bacterial phagocytosis by both human and murine macrophages. Exposure of macrophages to PMN secretion markedly enhanced phagocytosis of IgG-opsonized Staphylococcus aureus both in vitro and in murine models in vivo. PMN secretion activated macrophages, resulting in upregulation of the Fcgamma receptors CD32 and CD64, which then mediated the enhanced phagocytosis of IgG-opsonized bacteria. The phagocytosis-stimulating activity within the PMN secretion was found to be due to proteins released from PMN primary granules; thorough investigation revealed heparin-binding protein (HBP) and human neutrophil peptides 1-3 (HNP1-3) as the mediators of the macrophage response to PMN secretion. The use of blocking antibodies and knockout mice revealed that HBP acts via beta(2) integrins, but the receptor for HNP1-3 remained unclear. Mechanistically, HBP and HNP1-3 triggered macrophage release of TNF-alpha and IFN-gamma, which acted in an autocrine loop to enhance expression of CD32 and CD64 and thereby enhance phagocytosis. Thus, we attribute what may be a novel role for PMN granule proteins in regulating the immune response to bacterial infections.
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| 3. |
- Végvári, Ákos, et al.
(author)
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Essential tactics of tissue preparation and matrix nano-spotting for successful compound imaging mass spectrometry
- 2010
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In: Journal of Proteomics. - : Elsevier BV. - 1876-7737 .- 1874-3919. ; 73:6, s. 1270-1278
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Journal article (peer-reviewed)abstract
- The ultimate goal of MALDI-Imaging Mass Spectrometry (MALDI-IMS) is to achieve spatial localization of analytes in tissue sections down to individual tissue compartments or even at the level of a few cells. With compound tissue imaging, it is possible to track the transportation of an unlabelled, inhaled reference compound within lung tissue, through the application of MALDI-IMS. The procedure for isolation and preparation of lung tissues is found to be crucial in order to preserve the anatomy and structure of the pulmonary compartments. To avoid delocalization of analytes within lung tissue compartments we have applied an in-house designed nano-spotter, based on a microdispenser mounted on an XY table, of which movement and spotting functionality were fully computer controlled. We demonstrate the usefulness of this platform in lung tissue sections isolated from rodent in vivo model, applied to compound tissue imaging as exemplified with the determination of the spatial distribution of (1 alpha,2 beta,4 beta,7 beta)-7-[(hydroxidi-2-thienylacetyl)oxy]-9,9-dimethyl-3-oxa-9-azoniatric yclo[3.3.1.0(2,4)]nonane, also known as tiotropium. We provide details on tissue preparation protocols and sample spotting technology for successful identification of drug in mouse lung tissue by using MALDI-Orbitrap instrumentation.
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