6 research outputs found

    Accurate LC-MS/MS Analysis of Diacylglycerols in Human Plasma with Eliminating Matrix Effect by Phospholipids Using Fluorous Biphasic Extraction

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    We developed an accurate method for determining diacylglycerols (DAGs) in human plasma using a fluorous biphasic liquid–liquid extraction method, followed by liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis. The lipid mixture in the plasma was first extracted with chloroform by using the Bligh–Dyer method. The resulting solution was subjected to fluorous biphasic liquid–liquid extraction to remove phospholipids, which are known to cause matrix effects during the LC-MS/MS analysis. In this method, phospholipids in a lipid mixture solution (nonfluorous solvent) were selectively extracted to tetradecafluorohexane (fluorous solvent) via the specificity of fluorous affinity by forming a complex with a perfluoro­polyether­carboxylic acid-lanthanum(III) salt. The remaining DAGs in the nonfluorous solvent could be directly injected into the LC system through the positive electrospray ionization-MS/MS mode. The removal rate of the phospholipids through the fluorous biphasic extraction was more than 99.9%; thus, the matrix-effect-eliminating analysis of DAGs in human plasma with LC-MS/MS was enabled. Furthermore, the applicability of this method and the possibility of using DAGs as biomarkers were evaluated by applying this method to human plasma samples obtained from major depressive disorder as a related disease

    Epidemiological Study of Pathogenic <i>Leptospira</i> in Raccoons (<i>Procyon lotor</i>) in a Suburb of Tokyo, Japan

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    Leptospirosis is a zoonosis that affects humans and animals worldwide. Raccoons (Procyon lotor), adopted in urban environments, may act as potential reservoirs of Leptospira. We investigated the prevalence of pathogenic Leptospira in the kidney and urine samples of raccoons living in Tokyo, as well as anti-leptospiral antibodies in their serum, and aimed to examine the factors that expose raccoons to Leptospira. Polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) were used to detect leptospiral DNA and anti-leptospiral antibodies, respectively. Thirty-six of 156 raccoons (23.1%) were positive by PCR, and 16 of 165 raccoons (9.7%) were positive by ELISA. The prevalence and seroprevalence rates differed depending on the raccoon dispersal period. We used univariable logistic regression to estimate the environmental factors associated with pathogenic Leptospira and anti-leptospiral antibodies in raccoons. Significant differences were observed in the PCR results for the seasons (spring–summer) (p = 0.01), average monthly temperature (p p p = 0.06). We identified a pattern of leptospiral spread in raccoon dispersal and environmental factors that expose raccoons to Leptospira
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