scholarly journals Bringing SEM and MSI Closer Than Ever Before: Visualizing Aspergillus and Pseudomonas Infection in the Rat Lungs

2020 ◽  
Vol 6 (4) ◽  
pp. 257
Author(s):  
Tereza Juříková ◽  
Dominika Luptáková ◽  
Olga Kofroňová ◽  
Anton Škríba ◽  
Jiří Novák ◽  
...  
Keyword(s):  
Mass Spectrometry Imaging ◽  
Ionization Mass ◽  
Bacterial Cells ◽  
Laser Desorption Ionization ◽  
Rat Lung ◽  
Frozen Sections ◽  
Molecular Biomarker ◽  
Tissue Sections ◽  
Pseudomonas Infection ◽  
Ethanol Series

A procedure for processing frozen rat lung tissue sections for scanning electron microscopy (SEM) from deeply frozen samples initially collected and stored for matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) was developed. The procedure employed slow thawing of the frozen sections while floating on the surface and melting in a fixative solution. After the float-washing step, the sections were dehydrated in a graded ethanol series and dried in a critical point dryer. The SEM generated images with well-preserved structures, allowing for monitoring of bacterial cells and fungal hyphae in the infected tissue. Importantly, the consecutive nonfixed frozen sections were fully compatible with MALDI-MSI, providing molecular biomarker maps of Pseudomonas aeruginosa. The protocol enables bimodal image fusion in the in-house software CycloBranch, as demonstrated by SEM and MALDI-MSI.

scholarly journals Diagnosis of Agglomeration and Crystallinity of Active Pharmaceutical Ingredients in Over the Counter Headache Medication by Electrospray Laser Desorption Ionization Mass Spectrometry Imaging

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 610
Author(s):  
Mariann Inga Van Meter ◽  
Salah M. Khan ◽  
Brynne V. Taulbee-Cotton ◽  
Nathan H. Dimmitt ◽  
Nathan D. Hubbard ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrometry Imaging ◽  
Laser Desorption ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Active Pharmaceutical Ingredients ◽  
Laser Desorption Ionization ◽  
Over The Counter ◽  
Pharmaceutical Ingredients ◽  
Desorption Ionization

Agglomeration of active pharmaceutical ingredients (API) in tablets can lead to decreased bioavailability in some enabling formulations. In a previous study, we determined that crystalline APIs can be detected as agglomeration in tablets formulated with amorphous acetaminophen tablets. Multiple method advancements are presented to better resolve agglomeration caused by crystallinity in standard tablets. In this study, we also evaluate three “budget” over-the-counter headache medications (subsequently labeled as brands A, B, and C) for agglomeration of the three APIs in the formulation: Acetaminophen, aspirin, and caffeine. Electrospray laser desorption ionization mass spectrometry imaging (ELDI-MSI) was used to diagnose agglomeration in the tablets by creating molecular images and observing the spatial distributions of the APIs. Brand A had virtually no agglomeration or clustering of the active ingredients. Brand B had extensive clustering of aspirin and caffeine, but acetaminophen was observed in near equal abundance across the tablet. Brand C also had extensive clustering of aspirin and caffeine, and minor clustering of acetaminophen. These results show that agglomeration with active ingredients in over-the-counter tablets can be simultaneously detected using ELDI-MS imaging.

scholarly journals Mass Spectrometry Imaging (MSI) Delineates Thymus-Centric Metabolism In Vivo as an Effect of Systemic Administration of Dexamethasone

2021 ◽  
Vol 11 (22) ◽  
pp. 11038
Author(s):  
Yudai Tsuji ◽  
Shinichi Yamaguchi ◽  
Tomoyuki Nakamura ◽  
Masaya Ikegawa
Keyword(s):  
Mass Spectrometry ◽  
Single Molecule ◽  
Mass Spectrometry Imaging ◽  
Apoptotic Cell ◽  
Systemic Administration ◽  
Ionization Mass ◽  
Laser Desorption Ionization ◽  
Energy Status ◽  
Cortex Of The Thymus

Matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) is increasingly used in a broad range of research due to its ability to visualize the spatial distribution of metabolites in vivo. Here, we have developed a method, named thoracic Mass Spectrometry Imaging (tMSI), as a standard protocol of molecular imaging of whole-animal sectioning in various settings of mice in vivo. Further application of the strategy that involved the systemic administration of dexamethasone (DEX) in mice, enabled a dynamic shift in the energy status of multiple thoracic organs to be visualized, based on tMSI data of purine and pyrimidine metabolites. Furthermore, with the introduction of uniform manifold approximation and projection (UMAP) for tMSI data, metabolic profiles normally localized in the cortex and cortico-medullary junction (CMJ) of the thymus were drastically shifted as minor profiles into the medulla of DEX-treated thymus. As a massive apoptotic cell death in the thymic cortex was noticeable, a single molecule, which was upregulated in the cortex of the thymus, enabled us to predict ongoing immunosuppression by in vivo DEX-administration.

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