Publications by authors named "Tae-Hun Hahm"

Article Synopsis
  • Organophosphoate (OP) chemicals inhibit the enzyme acetylcholinesterase (AChE), making it challenging to study OP poisoning due to animals' natural resistance from serum carboxylesterase.
  • * A new genetically modified mouse strain, KIKO, was created to lack serum carboxylase and to express a human-like AChE protein, providing a better model for OP research.
  • * In the study, KIKO mice showed increased acetylcholine levels after OP exposure, and the presence of a reactive countermeasure in the brain was detected, highlighting the potential of these mice for developing OP antidotes.*
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Preclinical models are essential research tools before novel therapeutic or diagnostic methods can be applied to humans. These range from in vitro cell monocultures to vastly more complex animal models, but clinical translation to humans often fails to deliver significant results. Three-dimensional (3D) organoid systems are being increasingly studied to establish physiologically relevant in vitro platforms in a trade-off between the complexity of the research question and the complexity of practical experimental setups.

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Article Synopsis
  • - The authors found that co-crystallizing fluorophores with MALDI imaging matrices can boost fluorophore brightness significantly (up to 79 times), enhancing tissue autofluorescence.
  • - This method, called FluoMALDI, allows simultaneous imaging of biological samples using both fluorescence microscopy and MALDI imaging, simplifying the process since both methods can target the exact same cells without physical alterations.
  • - The study demonstrates FluoMALDI's potential with various fluorophores in brain and kidney tissues, indicating it could advance imaging techniques in fields like cell biology and pathology.
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Multimodal tissue imaging techniques that integrate two complementary modalities are powerful discovery tools for unraveling biological processes and identifying biomarkers of disease. Combining Raman spectroscopic imaging (RSI) and matrix-assisted laser-desorption/ionization (MALDI) mass spectrometry imaging (MSI) to obtain fused images with the advantages of both modalities has the potential of providing spatially resolved, sensitive, specific biomolecular information, but has so far involved two separate sample preparations, or even consecutive tissue sections for RSI and MALDI MSI, resulting in images with inherent disparities. We have developed RaMALDI, a streamlined, integrated, multimodal imaging workflow of RSI and MALDI MSI, performed on a single tissue section with one sample preparation protocol.

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Anthocyanins are flavonoid compounds that are natural color pigments occurring in various colored plants, such as berry fruits, vegetables, and grapes. With the elucidation of their various physiological effects, anthocyanins have been identified as promising functional food ingredients. However, findings on the bioavailability of anthocyanins, which are present in various chemical structures in foods, are limited; their intestinal absorption behaviors, including their transport route(s), have not been fully explained.

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Article Synopsis
  • MALDI-MS imaging faces challenges in quantitative analysis due to inconsistencies in mass spectrometry (MS) intensity caused by variable matrix crystals in tissue samples.
  • A new method, using fluorescence-assisted spraying with the fluorescent reagent rhodamine 6G (R6G), establishes consistent matrix conditions, leading to more reproducible results.
  • This technique enabled accurate quantification of important compounds, including nifedipine and ferulic acid in rat kidney tissue, showing significant improvement in measurement reliability.
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Objective: To clarify the pathogenesis of human atheroma, the origin of deposited lipids, the developmental mechanism of liponecrotic tissue, and the significance of the oxidation of phospholipids were investigated using mass spectrometry-aided imaging and immunohistochemistry.

Unlabelled: Atherosclerotic lesions in human coronary arteries were divided into 3 groups: pathologic intimal thickening with lipid pool, atheroma with lipid core, and atheroma with necrotic core. The lipid pool and lipid core were characterized by the deposition of extracellular lipids.

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It is unknown whether intestinal absorption of acylated anthocyanins occurs in their intact or metabolized form. In this study, with the aid of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) imaging, intestinal absorption of acylated anthocyanins was visually investigated. Anthocyanin extracts from purple carrots were orally administered to Sprague-Dawley rats.

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