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  1. No Access

    Article

    Separation and identification of monoglucuronides of vitamin D3 metabolites in urine by derivatization-assisted LC/ESI–MS/MS using a new Cookson-type reagent

    A liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI–MS/MS) method was developed using a new Cookson-type reagent, 4-[4-(1-pipelidinyl)phenyl]-1,2,4-triazoline-3,5-dione (PIPTAD), t...

    Kazunari Takada, Shoujiro Ogawa, Natsuki Yoshida, Tatsuya Higashi in Analytical Sciences (2023)

  2. No Access

    Article

    Improvement of analysis throughput for LC/MS assay

    Shoujiro Ogawa in Analytical Sciences (2022)

  3. No Access

    Article

    An LC/MS/MS method for quantifying testosterone and dehydroepiandrosterone sulfate in four different serum samples during a single run

    Simultaneous measurements of the circulating testosterone (TS) and dehydroepiandrosterone sulfate (DHEAS) are deemed to be helpful for the assessment of men’s health. Liquid chromatography/electrospray ionizat...

    Shunsuke Fujimura, Takenori Ito, Shoujiro Ogawa, Takayuki Ishige… in Analytical Sciences (2022)

  4. No Access

    Article

    Enhancing LC/ESI-MS/MS Throughput for Plasma Bile Acid Assay by Derivatization-based Sample-Multiplexing

    Liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) enables the accurate and precise quantification of various analytes at very low concentrations, but it has room for improve...

    Akihiro Jo, Sae Koyagi, Wataru Hobo, Saori Otani, Shoujiro Ogawa… in Analytical Sciences (2020)

  5. No Access

    Article

    Changes in Polyamine Content in Rice Bran due to Fermentation with Aspergillus oryzae Analyzed by LC/ESI-MS/MS Combined with Derivatization

    Many studies have demonstrated that the dietary supplementation of polyamines, especially spermidine (SPD), prevents age-related diseases. Rice bran is rich in polyamines and their amounts could be increased b...

    Yukiko Horie, Ayaka Goto, Sumi Tsubuku, Mari Itoh, Shigeo Ikegawa… in Analytical Sciences (2019)

  6. No Access

    Article

    A Method for Quantification of Tetrahydroglucocorticoid Glucuronides in Human Urine by LC/MS/MS with Isotope-coded Derivatization

    The determination of urinary tetrahydroglucocorticoid (THGC) glucuronides might prove helpful in the diagnosis, pathophysiological analysis and assessment of the therapeutic efficacy of the diseases caused by ...

    Takaaki Matsumoto, Wataru Yamazaki, Akihiro Jo, Shoujiro Ogawa… in Analytical Sciences (2018)

  7. No Access

    Article

    Development and validation of the simultaneous measurement of four vitamin D metabolites in serum by LC–MS/MS for clinical laboratory applications

    The quantification of serum 25-hydroxyvitamin D [25(OH)D] as an indicator of vitamin D status is currently primarily conducted by immunoassays, yet LC–MS/MS would allow more accurate determination. Furthermore...

    Mamoru Satoh, Takayuki Ishige, Shoujiro Ogawa… in Analytical and Bioanalytical Chemistry (2016)

  8. No Access

    Article

    Analysis of urinary vitamin D3 metabolites by liquid chromatography/tandem mass spectrometry with ESI-enhancing and stable isotope-coded derivatization

    The determination of the urinary vitamin D3 metabolites might prove helpful in the assessment of the vitamin D status. We developed a method for the determination of trace vitamin D3 metabolites, 25-hydroxyvitami...

    Shoujiro Ogawa, Satoshi Ooki, Kenta Shinoda… in Analytical and Bioanalytical Chemistry (2014)

  9. No Access

    Article

    Stereoselective Synthesis and NMR Characterization of C-24 Epimeric Pairs of 24-Alkyl Oxysterols

    Two pairs of C-24 epimeric (24R)-/(24S)-24-hydroxy-24-methyl-5α-cholestan-3β-yl acetates and (24R)-/(24S)-25-hydroxy-24-methyl-5α-cholestan-3β-yl acetates as well as some related 24-ethyl oxysterol analogs were s...

    Shoujiro Ogawa, Hiroaki Kawamoto, Takashi Mitsuma, Hiroki Fujimori… in Lipids (2013)

  10. No Access

    Article

    Lupane triterpenes with a carbonyl group at C-20 induce cancer cell apoptosis

    We evaluated the effects of various lupane triterpenes on B16 2F2 mouse melanoma cell differentiation and proliferation. All of the compounds tested (numbered 1–6) induced melanogenesis of B16 2F2 cells, a marker...

    Keishi Hata, Shoujiro Ogawa, Mitsuko Makino… in Journal of Natural Medicines (2008)

  11. No Access

    Article

    Biomimetic oxidation of unactivated carbons in steroids by a model of cytochrome P-450, oxorutheniumporphyrinate complex

    Biomimetic oxidation of unactivated carbons for structurally different steroids was studied with a model of cytochrome P-450, oxorutheniumporphyrinate complex, which is generated in situ by 2,6-dichloropyridine N

    Takashi Iida, Shoujiro Ogawa, Shouhei Miyata, Takaaki Goto, Nariyasu Mano… in Lipids (2004)

  12. No Access

    Article

    An Improved Method for the Capillary Gas Chromatographic Derivatization of Polyhydroxylated Steroids Having tert-Hydroxyl Groups

    An improved method for a suitable derivatization of polyhydroxylated steroids having one or two tert-hydroxyl groups at the 5β-, 14α-, 17α-, 24-, and/or 25-positions by capillary gas chromatography (CGC) is descr...

    Takashi Iida, Keisuke Shiraishi, Shoujiro Ogawa, Junichi Goto… in Analytical Sciences (2003)

  13. No Access

    Article

    Functionalization of unactivated carbons in 3α,6- and 3α,24-dihydroxy-5β-cholane derivatives by dimethyldioxirane

    Direct remote functionalization of unactivated carbons by dimethyldioxirane (DMDO) was examined for 3α,6- and 3α,24-dihydroxy-5β-cholane derivatives. DMDO oxidation of stereoisomeric methyl 3α,6-diacetoxy-5β-c...

    Takashi Iida, Keisuke Shiraishi, Shoujiro Ogawa, Takaaki Goto, Nariyasu Mano… in Lipids (2003)