Concentrations of circulating 24S-hydroxycholesterol (24SOHChol) are of interest as a practical measure of cholesterol efflux from the human brain. The current method of choice for 24SOHChol quantification is with gas chromatography-mass spectrometry (GC-MS). Liquid chromatography-mass spectrometry (LC-MS) methods to detect 24SOHChol have been described, but they lack rigorous high-performance liquid chromatography (HPLC) separation of a closely eluting isomeric oxysterol, 25-hydroxycholesterol. This is important because 25-hydroxycholesterol can be present in significant amounts and tandem mass spectrometry (MS/MS) cannot completely differentiate 24SOHChol. We describe an LC-MS method with rapid chromatographic separation of the oxysterols to permit accurate determination of plasma 24SOHChol. The availability of an LC-MS method offers advantages such as simplified sample work-up and analysis.
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http://dx.doi.org/10.1016/j.ab.2008.05.037 | DOI Listing |
J Vis Exp
January 2025
Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee;
Cardiovascular disease (CVD) is the leading cause of death in the United States. Damage in the cardiovascular system can be due to environmental exposure, trauma, drug toxicity, or numerous other factors. As a result, cardiac tissue and vasculature undergo structural changes and display diminished function.
View Article and Find Full Text PDFEur J Nucl Med Mol Imaging
January 2025
Institute of Radiation Medicine, Fudan University, Xietu Road 2094, Shanghai, 200032, China.
Objectives: Mesothelin (MSLN) is an antigen that is overexpressed in various cancers, and its interaction with tumor-associated cancer antigen 125 plays a multifaceted role in tumor metastasis. The serum MSLN expression level can be detected using enzyme-linked immunosorbent assay; however, non-invasive visualization of its expression at the tumor site is currently lacking. Therefore, the aim of this study was to develop a molecular probe for imaging MSLN expression through positron emission tomography (PET).
View Article and Find Full Text PDFBraz J Microbiol
January 2025
Laboratorio de Biocatalizadores y sus Aplicaciones, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Iguá 4225, Montevideo, Uruguay.
Proteases are hydrolases that act on peptide bonds, releasing amino acids and/or oligopeptides, and are involved in essential functions in all organisms. They represent an important segment of the global enzyme market, with applications in the food, leather, detergent, and pharmaceutical industries. Depending on their industrial use, proteases should exhibit high activity under extreme conditions, such as low temperatures, e.
View Article and Find Full Text PDFAnal Chem
January 2025
Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Beijing Mass Spectrum Center, Institute of Chemistry Chinese Academy of Sciences, Beijing 100190, China.
Monounsaturated fatty acids (MUFA) are an important class of nutrients and are involved in lipid metabolism. The positions of the C=C bond and cis-trans isomerism have a significant influence on their physiological activity. However, simultaneously detecting these two structural properties has been challenging due to multiple isomers of MUFA.
View Article and Find Full Text PDFEnviron Sci Technol
January 2025
U.S. Environmental Protection Agency/Office of Research and Development, Durham, North Carolina 27711, United States.
Humans experience widespread exposure to anthropogenic per- and polyfluoroalkyl substances (PFAS) through various media, which can lead to a wide range of negative health impacts. Tap water is an important source of exposure in communities with any degree of contamination but routine or large-scale PFAS monitoring often depends on targeted analytical methods limited to measuring specific PFAS. We analyzed 680 tap water samples from the American Healthy Homes Survey II for PFAS using non-targeted analysis (NTA) to expand the range of detectable PFAS.
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