Biomedical subjects

Toshie Takahashi

Publications and source records attributed to Toshie Takahashi.

3 recordsLinked to original sources

PubMed2005

A multiplex quantitation method for eicosanoids and platelet-activating factor using column-switching reversed-phase liquid chromatography-tandem mass spectrometry.

Eicosanoids and platelet-activating factor (PAF) are phospholipid-derived lipid mediators produced by various tissues and cells through a cascade pathway. For a comprehensive analysis of these lipid mediators, a simultaneous quantitation method with sensitivity and reliability is necessary. This article details a development of column-switching reversed-phase liquid chromatography-tandem mass spectrometry for multiplex quantitation of eicosanoids and PAF. The adsorptive nature of lipids caused significant loss of signal in a conventional column-switching configuration. The use of an online-dilution method allowed use of 100% methanol as a sample solvent, which prevented sample adsorption to contacting surfaces. Addition of 0.2% formic acid to the sample solvent was required for the successful introduction of LTC4 to the trapping column and minimizing its carryover. The optimized method provided rapid analysis of 14 lipid mediators with a throughput of 96 samples/24 h, lower limits of quantitation of 5 pg on column, and linear calibration ranges up to 2000-5000 pg. The system was highly compatible with solid-phase-extracted samples, as methanol-eluted fractions were directly injected without reconstitution. The analysis of lipid mediator production of macrophage-like RAW264.7 cells demonstrated that the cell-based assay can be performed in a 96-well format, suitable for metabolomics analyses and/or screening strategies.

Animals↗

PubMed2005

Pathway-oriented profiling of lipid mediators in macrophages.

Macrophages produce various kinds of lipid mediators including eicosanoids and platelet-activating factor. Since they are produced from common precursors, arachidonic acid-containing phospholipids, regulations of metabolic pathways underlie the patterning of lipid mediator production. Here, we report a pathway-oriented profiling strategy of lipid mediators by a newly developed multiplex quantification system. We profiled mouse peritoneal macrophages in different activation states. The analysis of kinetics revealed the differences in the production time course of various lipid mediators, which also differed by the macrophage types. Scatterplot matrix analysis of the inhibitor study revealed correlations of lipid mediator species. The changes of these correlations provided estimates on the effects of lipopolysaccharide priming. We also found a highly linked production of 11-hydroxyeicosatetraenoic acid and prostaglandin E2, implying the in vivo property of cyclooxygenase-mediated 11-hydroxyeicosatetraenoic acid production. The present approach will serve as a strategy for understanding the regulatory mechanism of lipid mediator production.

Animals↗

PubMed2005

[Non-cardiogenic pulmonary edema induced by non-ionic radiographic contrast media during the coil embolization for a ruptured cerebral aneurysm].

We describe a 48(correction of 44) year-old woman, who presents a non-cardiogenic pulmonary edema caused by non-ionic radiographic contrast medium. She suffered from subarachnoid hemorrhage due to dissecting aneurysm of right vertebral artery. Cerebral angiography followed by coil embolization for the aneurysm was performed. During the interventional procedure, saturation of blood oxygen suddenly declined and chest X-ray photography obviously revealed pulmonary edema. At first we dealt with it as neurogenic phenomenon but subsequently interpreted it to non-cardiogenic pulmonary edema induced by radiographic contrast medium, since intra-arterial injection of contrast medium at follow-up angiography led the symptoms into more fulminant status. Intensive care including endotracheal intubation and continuous positive airway pressure ventilation consequently achieved complete remission and the patient discharged without any sequelae. Although low osmolar, non-ionic contrast medium has been regarded as relatively safe, severe reaction such as dyspnea, hypotension and cardiac arrest could emerge at certain intervals. We must perceive the adverse effects of it because the usage of contrast medium will dramatically increase with development of diagnostic radiographical methodology and interventional neurosurgery.

Aortic Dissection↗