Yumi Akiyama
Chiba University
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Publication
Featured researches published by Yumi Akiyama.
Journal of Chromatography B: Biomedical Sciences and Applications | 2000
Naoki Yoshioka; Yumi Akiyama; Nobuyuki Takeda
A sensitive and rapid high-performance liquid chromatographic screening method is described for the determination of anabolic steroid trenbolone in bovine muscle and liver. Trenbolone was analyzed as α- and β-trenbolone. Samples were extracted with ethyl acetate and cleaned up on a silica solid-phase extraction (SPE) cartridge. Liver samples were cleaned up on a multifunctional SPE cartridge before using a silica SPE cartridge. Analysis of α- and β-trenbolone was performed by reversed-phase high-performance liquid chromatography (HPLC) with a fluorescence detector. The detection limits for this method were estimated to be 0.2 and 1.0 ng/g in bovine muscle and liver, respectively. The mean recoveries spiked in muscle at 2 ng/g and in liver at 10 ng/g were over 80%.
Japanese Journal of Infectious Diseases | 2017
Yumi Akiyama; Hiroko Futai; Etsuko Saito; Kenichi Ogita; Hiroshi Sakae; Masaharu Fukunaga; Hidetaka Tsuji; Masatsugu Chikahira; Atsushi Iguchi
Subtypes of stx1 and stx2 in 45 Shiga toxin-producing Escherichia coli (STEC) strains isolated from cattle were investigated by PCR. Only subtype stx1a was detected among all the stx1-positive strains. The major stx2 subtype was stx2a followed by stx2d, stx2c, stx2b, and stx2g in decreasing order of frequency. stx2c was found in strains of serotypes O157 and O174. stx2d was found in 11 strains. These strains were confirmed by DNA sequencing to carry both the activatable tail and the END motif; all were eae-negative, and 3 contained stx2d as the only stx. stx2g was found in 2 strains in association with stx2a, estA1, and astA. In addition, 7 hybrid strains of shigatoxigenic and enterotoxigenic E. coli (STEC/ETEC) were found to harbor one or both of stx1a and stx2a (stx1a/stx2a) and estA1. Among 27 serotypes of STEC strains isolated from cattle, O157:H7 and O109:H- strains were eae-positive. Other putative adhesin genes, such as saa, iha, espP, and lpfAO113 were detected in more than 12 serotypes.
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 2015
Yumi Akiyama; Etsuko Saito; Hiroko Futai; Kenichi Ogita; Hiroshi Sakae; Masaharu Fukunaga; Hidetaka Tsuji; Masatsugu Chikahira; Masashi Mimura
Pathogenic genes such as stx1, stx2, STh gene, STp gene, LT gene, invE, eae, aggR, afaD, astA, cdt and cnf were investigated in Escherichia coli isolated from cattle during Nov. 2012 and Aug. 2013. Plural pathogenic genes were concurrently detected by multiplex PCR, and screen-positive genes were confirmed and sub-classified by PCR. Among 100 cattle investigated, 180 E. coli strains with diarrheic genes (DEC) were detected in 79 cattle, and 45 of them, isolated from 32 cattle, were Shiga toxin-producing E. coli (STEC). More than 30% of cattle carried astA, cdt, cnf and stx2 in descending order. STh gene, LT gene, invE, aggR and afaD were not detected in this study. Both stx1 and stx2 were concurrently detected from 6 of 45 STEC strains and stx2 alone was detected from 19. Seventeen STEC strains carried STp gene, astA, or cdt along with stx1 or stx2. Additionally, 135 remaining DEC were classified into 18 enterotoxigenic E. coli with STp gene, 25 enteropathogenic E. coli with eae, and 92 other DEC with astA, cdt and cnf. Both O and H serotypes were identified in 48 strains, including O157 : H7, O1H7 and so on. O157 : H7 were identified in 3 strains that carried stx2 and eae together, as found in human pathogenic strains isolated from patients with gastroenteritis and hemolytic-uremic syndrome.
Journal of Chromatography A | 2004
Naoki Yoshioka; Yumi Akiyama; Kiyoshi Teranishi
Journal of The Food Hygienic Society of Japan (shokuhin Eiseigaku Zasshi) | 1996
Yumi Akiyama; Miho Yang; Takao Mitsuhashi; Nobuyuki Takeda; Masahiko Tsuji
Journal of AOAC International | 2002
Yumi Akiyama; Naoki Yoshioka; Masahiko Tsuji
Analytical Sciences | 1997
Masahiko Tsuji; Yumi Akiyama; Miho Yano
Food Control | 2010
Naoki Yoshioka; Yumi Akiyama; Tomofumi Matsuoka; Takao Mitsuhashi
Journal of Pesticide Science | 2009
Yumi Akiyama; Tomofumi Matsuoka; Takao Mitsuhashi
Analytical Sciences | 1985
Kazunori Kobayashi; Yumi Akiyama; Kayo Kawaguchi; Shinzo Tanabe; Toshio Imanari