Publications (6)5.71 Total impact
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Article: [Determination of vedaprofen in livestock products and seafoods by liquid chromatography-tandem mass spectrometry].
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ABSTRACT: A novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the trace residue determination of vedaprofen (VPF) in livestock products and seafoods. VPF was extracted from each sample with acidified acetone, and the crude extract was re-extracted with ethyl acetate and NaCl solution. Clean-up was performed using a weak anion exchange cartridge (Bond Elut DEA). The LC separation was performed on a C18 column using acetonitrile-0.0025 mol/L formic acid (3 : 2) as the mobile phase and MS was run in the negative ion electrospray ionization mode. The calibration curve was linear in the range of 0.001-0.1 µg/mL VPF. The mean recoveries from equine muscle, cattle muscle, cattle liver, cattle fat, salmon, eel, corbicula, milk, egg and buckwheat honey were 72-94%, and the relative standard deviations (RSDs) were 1.1-2.0%. Limits of quantitation (LOQs) ranged from 0.001 to 0.007 µg/g.Journal of the Food Hygienic Society of Japan (Shokuhin Eiseigaku Zasshi) 01/2011; 52(5):304-8. · 0.43 Impact Factor -
Article: [Determination of 4-hydroxycoumarin rodenticides in animal products, fishery products, and honey by liquid chromatography-tandem mass spectrometry].
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ABSTRACT: A sensitive and selective method for the determination of 4-hydroxycoumarin-type rodenticides (warfarin, coumatetralyl, bromadiolone, and brodifacoum) in animal products, fishery products, and honey was developed. 4-Hydroxycoumarin rodenticides were extracted with acidified acetone, and the crude extract was purified by liquid-liquid partitioning followed by PSA column cleanup. Gradient liquid chromatographic separation was performed by using an Inertsil ODS-4 column, with methanol and water containing ammonium acetate as the mobile phase. Detection was carried out on a tandem mass spectrometer with electrospray ionization in the negative mode. Average recoveries from bovine muscle, bovine liver, bovine fat, swine muscle, salmon, eel, freshwater clam, egg, milk, and honey spiked at 0.0005-0.001 mg/kg were in the range of 79-108%, and the relative standard deviations were 2-8%. The limits of quantitations of the developed method were 0.0005 mg/kg for brodifacoum, 0.001 mg/kg for warfarin, coumatetralyl, and bromadiolone.Journal of the Food Hygienic Society of Japan (Shokuhin Eiseigaku Zasshi) 01/2011; 52(4):244-50. · 0.43 Impact Factor -
Article: [Determination of pindone in animal products, fishery products, and honey by LC-MS/MS].
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ABSTRACT: A sensitive and selective analytical method for the determination of the rodenticide pindone in animal products, fishery products, and honey by LC-MS/MS was developed. Pindone was extracted with acidified acetone, and the crude extract was purified by liquid-liquid partitioning, followed by silica gel and ODS column chromatography. LC separation was performed on an ODS column with methanol/water containing ammonium acetate as the mobile phase, and detection was carried out using tandem mass spectrometry (MS/MS) with electrospray ionization (ESI) in the negative mode. The average recoveries from fortified bovine muscle, bovine liver, bovine fat, chicken muscle, salmon, eel, freshwater clam, egg, milk, and honey spiked at 0.001 mg/kg were in the range of 76-92%, and the relative standard deviations were 4-8%. The limit of quantitation (S/N≥10) of the developed method was 0.001 mg/kg for all the tested foods.Journal of the Food Hygienic Society of Japan (Shokuhin Eiseigaku Zasshi) 01/2011; 52(5):294-8. · 0.43 Impact Factor -
Article: [Surveillance of perchlorate level in leafy vegetables and bottled water].
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ABSTRACT: Perchlorate (ClO(4)(-)) is both a naturally occurring and artificial compound, and it inhibits iodide uptake into the thyroid gland and disturbs thyroid function. It has been detected in many foods in the United States. In order to investigate perchlorate contamination in foods in Japan, perchlorate level in 82 leafy vegetable samples and 20 bottled mineral water samples was measured using a procedure based on the FDA's procedure, employing IC-MS/MS with (18)O(4)-labeled perchlorate as an internal standard. Among 82 leafy vegetable samples tested, perchlorate levels were under the LOQ (0.3 ng/g) in 3 samples and ranged from 0.3 ng/g to 29.7 ng/g in 79 samples. In 20 bottled water samples, perchlorate was under the LOQ (0.1 ng/mL) in 14 samples and ranged from 0.14 ng/mL to 0.35 ng/mL in 6 samples.Journal of the Food Hygienic Society of Japan (Shokuhin Eiseigaku Zasshi) 09/2009; 50(4):184-9. · 0.43 Impact Factor -
Article: Foxp3-expressing regulatory T cells expanded with CD28 superagonist antibody can prevent rat cardiac allograft rejection.
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ABSTRACT: It is well known that CD4(+)CD25(+) regulatory T (Treg) cells play a central role in the suppression of autoimmunity, inflammation and allograft rejection. Therefore, therapeutic agents that capable of enhancing the number and activity of this T-cell subset are highly desirable. The present study was designed to investigate the effects of superagonistic CD28-specific monoclonal antibody (supCD28 MAb) on preferentially expanded rat naturally occurring CD4(+)CD25(+) Treg (nTreg) cells and its applicability in cardiac transplantation. A single administration of supCD28 MAb preferentially proliferated nTreg cells. The increase of Foxp3 expression and polarization toward a Th2 cytokine profile correlated with decreased production of interferon-gamma and increased production of interleukin-4 and -10 in the expanded CD4(+)CD25(+) Treg subset, which was capable of suppressing CD4(+)CD25(-) T-cell proliferation after purification. Furthermore, supCD28 MAb administration revealed that nTreg cells were preferentially proliferating in vivo and recruited into the grafts, resulting in significant prolongation of full MHC-mismatch cardiac graft survival. Our data demonstrate that supCD28 MAb targets expansion of nTreg cells in vivo and maintains and enhances their regulatory functions, which represents a major advance toward the therapeutic use of polyclonally activated Treg cells as cellular therapy for treatment of allograft rejection.The Journal of heart and lung transplantation: the official publication of the International Society for Heart Transplantation 05/2008; 27(4):362-71. · 3.54 Impact Factor -
Article: Determination method for ractopamine in swine and cattle tissues using LC/MS.
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ABSTRACT: Simple and reliable methods using LC/MS have been developed for the determination of the beta-agonist ractopamine in swine and cattle tissues. Ractopamine was extracted with ethyl acetate from muscle and liver, and the ethyl acetate layer was evaporated to dryness. The residue was purified by partition with acetonitrile/n-hexane. In the case of fat, ractopamine was extracted and purified by partition with acetonitrile/n-hexane. The resulting acetonitrile solutions were evaporated to dryness. The residue was dissolved in methanol, and subjected to LC/MS. The LC separation was performed on a Wakosil-II 3C18HG column (150 x 3 mm i.d.) in isocratic mode with 0.05% trifluoroacetic acid-acetonitrile (80:20) as a mobile phase at a flow rate of 0.4 mL/min. The MS detection was performed in the selected ion recording (SIR) mode, with detection of the M + H+ ion of ractopamine (m/z 302) produced by electrospray ionization (ESI). The mean recoveries of the drug from swine muscle (0.01 microg fortified), fat (0.01 microg fortified) and liver (0.04 microg/g fortified) were 99.7%, 99.5% and 100.8%, and those from cattle samples were 108.3%, 97.0% and 109.4%, respectively. The relative standard deviations (RSDs) ranged from 0.1% to 9.5%. The limit of quantification (LOQ) of the drug was 1 ng/g.Journal of the Food Hygienic Society of Japan (Shokuhin Eiseigaku Zasshi) 11/2007; 48(5):144-7. · 0.43 Impact Factor
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Institutions
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2007
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National Institute of Health Sciences, Japan
Tokyo, Tokyo-to, Japan
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