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| 1.
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Murahashi, Tsuyoshi ; Kizu, Ryoichi ; Kakimoto, Hitoshi ; Toriba, Akira ; Hayakawa, Kazuichi
概要:
Diesel-engine exhaust and airborne particulates were collected in downtown and suburban areas and five mutagenic nitroarenes (2-nitrofluoranthene (NF), 1-, 2- and 4-nitropyrenes (NPs) and 6-nitrochrysene (NC) in benzene-ethanol extracts
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were determined by high-performance liquid chromatography with chemiluminescence detection. 1- and 4-NPs and 6-NC were found in diesel-engine exhaust particulates, however, 2-NF and 2-NP were not detected. On the other hand, all five nitroarenes were found in airborne particulates. Diurnal concentration patterns of 4-NP and 6-NC in the downtown area were similar to the pattern of 1-NP, but the patterns of 2-NF and 2-NP were different from the pattern of 1-NP. These results strongly suggested that 2-NF and 2-NP are formed in the atmosphere. Of the five nitroarenes, 2-NF had the largest suburban / downtown concentration ratio. 2- and 4-NPs and 6-NC all showed larger ratios than did 1-NP. These results showed that 2-NF and 2-NP were formed in the atmosphere, but that the secondary formation of 4-NP and 6-NC were not known. Taking mutagenic activity and the atmospheric concentration into consideration, the mutagenic contribution of 2-NF was estimated to be comparable with that of 1-NP in the downtown area, and more than that of 1-NP in the suburban area. This result suggested that the mutagenic contribution of the minor nitroarenes formed in urban air might not be negligible.
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| 2.
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Tang, Ning ; Sato, Kousuke ; Tokuda, Takahiro ; Tatematsu, Michiya ; Hama, Hirotaka ; Suematsu, Chikako ; Kameda, Takayuki ; Toriba, Akira ; Hayakawa, Kazuichi
概要:
Airborne particulates were collected at a background site (Wajima Air Monitoring Station; WAMS) on the Noto Peninsula, J
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apan from January 2006 to December 2007. 1-, 2-nitropyrenes (1-, 2-NPs) and 2-nitrofluoranthene (2-NFR), in the particulates were determined with a sensitive HPLC method with chemiluminescence detection. The average concentrations were higher in winter than in summer. A meteorological analysis indicated that the air samples collected in winter were transported mainly from Northeast China over the Japan Sea. Both the concentration ratios of 2-NFR to 1-NP and 1-NP to pyrene were similar to those in Shenyang in Northeast China which located along the air transportation route to WAMS, but not in Kanazawa which near WAMS. These results strongly suggest that most of the atmospheric 1-, 2-NPs and 2-NFR at WAMS in winter were long range transported from Northeast China. © 2014 Elsevier Ltd. All rights reserved.
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| 3.
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Tamura, Masayoshi ; Mochizuki, Naoki ; Nagatomi, Yasushi ; Harayama, Koichi ; Toriba, Akira ; Hayakawa, Kazuichi
概要:
Three compounds, hypothesized as fumonisin A1 (FA1), fumonisin A2 (FA2), and fumonisin A3 (FA3), were detected in a corn
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sample contaminated with mycotoxins by high-resolution liquid chromatography-Orbitrap mass spectrometry (LC-Orbitrap MS). One of them has been identified as FA1 synthesized by the acetylation of fumonisin B1 (FB1), and established a method for its quantification. Herein, we identified the two remaining compounds as FA2 and FA3, which were acetylated fumonisin B2 (FB2) and fumonisin B3 (FB3), respectively. Moreover, we examined a method for the simultaneous analysis of FA1, FA2, FA3, FB1, FB2, and FB 3. The corn samples were prepared by extraction using a QuEChERS kit and purification using a multifunctional cartridge. The linearity, recovery, repeatability, limit of detection, and limit of quantification of the method were >0.99, 82.9%–104.6%, 3.7%–9.5%, 0.02–0.60 μg/kg, and 0.05–1.98 μg/kg, respectively. The simultaneous analysis of the six fumonisins revealed that FA1, FA2, and FA3 were present in all corn samples contaminated with FB1, FB2, and FB 3. The results suggested that corn marketed for consumption can be considered as being contaminated with both the fumonisin B-series and with fumonisin A-series. This report presents the first identification and quantification of FA1, FA2, and FA3 in corn samples. © 2015 by the authors; licensee MDPI, Basel, Switzerland.
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| 4.
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Tanaka, Hiroki ; Sugita-Kounishi, Yuka ; Takino, Masahiko ; Tanaka, Toshitsugu ; Toriba, Akira ; Hayakawa, Kazuichi
概要:
金沢大学医薬保健研究域薬学系<br />By adopting a rapid and sensitive method for simultaneous detection of nivalenol (NIV), deoxynivalen
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ol (DON), fusarenon-X (FX), 3-acetyl deoxinivalenol (3ADON), HT-2 toxin (HT-2), T-2 toxin (T-2) and zearalenone (ZEN), the natural occurrence of these mycotoxins in biscuits made of wheat (201 samples) in Japan was surveyed. Samples were analyzed by LC/MS with atmospheric pressure photo ionization (APPI). Further confirmation was performed by liquid chromatography/time of flight mass spectrometry (LC/TOFMS). The average contamination of each Fusarium mycotoxin was 3.1, 23, 0.7, 0.1 and 4.2 ng/g for NIV, DON, HT-2, T-2 and ZEN, respectively. Multiple toxins were observed in 120 samples while FX and 3ADON were not detected. The incidence of these toxins was 41% for NIV, 98% for DON, 19% for HT-2, 11% for T-2 and 2% for ZEN. There were no significant differences in the concentration and incidence between conventional biscuits made of wheat and biscuits made of wheat for infants. This is the first report concerning the presence of NIV, DON, HT-2, T-2 and ZEN in biscuits in Japan. © 2010 The Pharmaceutical Society of Japan.
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| 5.
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Motoyama, Yumi ; Bekki, Kanae ; Chung, Sang Woon ; Tang, Ning ; Kameda, Takayuki ; Toriba, Akira ; Taguchi, Keiko ; Hayakawa, Kazuichi
概要:
The effect of four ortho-quinoid polycyclic aromatic hydrocarbons (PAHs) and seven para-quinoid PAHs on the viability of
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A549 cells were examined. The ortho-quinoid PAHs [1,2-naphthoquinone (1,2-NQ), 9,10-phenanthrenquinone (9,10-PQ), 5,6-chrysenequinone (5,6-CQ), and benzo[c]phenanthrene-5,6-quinone (B[c]P-5,6-Q)] overproduced hydrogen peroxide (H2O2) without being consumed themselves. These ortho-quinoid had strong cytotoxic effects except for 1,2-NQ, since of its tendency to covalently bind to thiol groups. The cytotoxicity appears to be due to the overproduction of H 2O2 by ortho-quinoid PAHs in a redox cycle coupled with the consumption of thiol group. In contrast, the para-quinoid PAHs were not as strong cytotoxic and did not produce H2O2. ©2009 The Pharmaceutical Society of Japan.
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| 6.
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Suzuki, Nobuo ; Maruyama, Yusuke ; Nakano, Masaki ; Hattori, Atsuhiko ; Honda, Masato ; Shimasaki, Yohei ; Sekiguchi, Toshio ; Mishima, Hiroyuki ; Wada, Shigehito ; Srivastav, Ajai K. ; Hayakawa, Kazuichi ; Oshima, Yuji
概要:
We recently demonstrated that prostaglandin E2 PG¿ increases osteoclastic activity and induces bone resorption in both i
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n vitro and in vivo experiments using goldfish. In the fish reproductive period, the plasma calcium (Ca) level in female teleosts increases remarkably to make vitellogenin, which is a major component of egg protein and a Ca-binding protein. In this period, however, there is no reported relationship between PGE2 and Ca metabolism in fish. To clarify the Ca metabolism in fish reproduction, we examined plasma PGE2 and Ca levels and measured tartrate-resistant acid phosphatase (TRAP) activities as an indicator of osteoclastic activity in goldfish. Plasma PGE2 levels in the reproductive stage significantly increased as compared with those in non-reproductive stages. Also, both plasma Ca and TRAP increased in the reproductive stage. Significant positive correlations were recognized between plasma Ca and the gonad somatic index (r=0.81, p<0.001), plasma Ca and plasma PGE2 levels (r=0.635, p<0.05), and plasma Ca and plasma TRAP activities (r=0.584, p<0.05) from the analysis using samples of both reproductive and nonreproductive stages. Taking these data into consideration, we suggested that PGE, acts on osteoclasts and increases plasma Ca as a result of osteoclastic bone resorption, and we concluded that PGE, is an important hormone in Ca metabolism during fish reproduction.
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| 7.
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Kameda, Takayuki ; Akiyama, Ayuko ; Yoshita, Morio ; Tachikawa, Chihiro ; Toriba, Akira ; Tang, Ning ; Hayakawa, Kazuichi
概要:
The mutagenicities and endocrine-disrupting activities of two isomers of mononitrated 1-hydroxypyrene [1-hydroxy-x-nitro
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pyrenes (1-OH-x-NPs); x = 2 and 5], which are not only photoreaction products of 1-nitropyrene (1-NP) but also constituent of ambient airborne particles, were evaluated for the first time using the Ames plate incorporation assay and the yeast two-hybrid assay, respectively. The mutagenicity of 1-OH-5-NP was weakly positive in the absence of rat liver S9, but was enhanced up to 3-fold with the metabolic activation by S9. On the contrary, 1-OH-2-NPdid not exhibit significant mutagenicity in the presence or absence of S9. 1-OH-5-NP showed weak estrogenic activity, but 1-OH-2-NP did not show any estrogenic activity. The concentration of 1-OH-5-NP that gave 10% of activity of 1.0 × 10-6M 17ß- estradiol (E2) was 5.4 × 10-7M. 1-OH-5-NP exhibited stronger antiestrogenic and antiandrogenic activities than 1-OH-2-NP. 1-OH-5-NP at a concentration of 1.0 × 10-6M inhibited 71 and 90%of ß-galactosidase activity induced by 1.0 × 10-9Mof E2 and 1.0 × 10-8M of 5a-dihydrotestosterone (DHT), respectively. On the other hand, 1.0 × 10-6M of 1-OH-2-NP inhibited 16 and 43% of ß-galactosidase activity induced by 1.0 × 10-9M of E2 and 1.0 × 10-8M of DHT, respectively. These findings point out the need for determining the environmental sources and distribution of 1-OH-2-NP and 1-OH-5-NP as well as the other hydroxynitropyrene isomers. © 2011 The Pharmaceutical Society of Japan.
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| 8.
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Hosozumi, Chiemi ; Toriba, Akira ; Chuesaard, Thanyarat ; Kameda, Takayuki ; Tang, Ning ; Hayakawa, Kazuichi
概要:
Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) is a widely used noninvasive biomarker of oxidative stress. A selective, se
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nsitive and rapid method for determining 8-OHdG in human urine was developed using hydrophilic interaction chromatography-tandem mass spectrometry (HILIC-MS/MS) with electrospray ionization. 8-OHdG and isotopically labeled 8-OHdG (internal standard) were separated on a HILIC column with a mobile phase of 10. mM ammonium acetate: acetonitrile (1:9, v/v) within 10. min and detected by using a positive electrospray ionization interface under the selected reaction monitoring mode. The detection limits of 8-OHdG (corresponding to a signal-to-noise ratio of 3) for the HILIC-MS/MS system and the conventional method using a reversed-phase column with MS/MS were 1.0 and 26.0. fmol/injection, respectively. The proposed method makes it possible to monitor the basal level of urinary 8-OHdG from non-exposed healthy subjects and can be used for large-scale human studies. © 2012 Elsevier B.V.
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| 9.
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Tamura, Masayoshi ; Mochizuki, Naoki ; Nagatomi, Yasushi ; Harayama, Koichi ; Toriba, Akira ; Hayakawa, Kazuichi
概要:
A high-resolution liquid chromatography-Orbitrap mass spectrometry (LC-Orbitrap MS) method was developed for simultaneou
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s determination of 20 Fusarium toxins (nivalenol, fusarenon-X, deoxynivalenol, 3-acetyl deoxynivalenol, 15-acetyl deoxynivalenol, HT-2 toxin, T-2 toxin, neosolaniol, diacetoxyscirpenol, fumonisin B1, fumonisin B2, fumonisin B3, fumonisin A1, fumonisin A2, fumonisin A3, zearalenone, α-zearalenol, β-zearalenol, α-zearalanol, and β-zearalanol) in cereals. The separation of 20 Fusarium toxins with good peak shapes was achieved using a pentafluorophenyl column, and Orbitrap MS was able to detect accurately from cereal matrix components within ±0.77 ppm. The samples were prepared using a QuEChERS kit for extraction and a multifunctional cartridge for purification. The linearity, repeatability, and recovery of the method were >0.9964, 0.8%–14.7%, and 71%–106%, respectively. Using this method, an analysis of 34 commercially available cereals detected the presence of deoxynivalenol, 15-acetyl deoxynivalenol, fumonisin B1, fumonisin B2, fumonisin B3, fumonisn A1, fumonisin A2, fumonisin A3, and zearalenone in corn samples with high concentration and frequency. Trichothecenes was detected from wheat samples with high frequency; in particular, the concentration of deoxynivalenol was high. Conversely, α-zearalenol, β-zearalenol, α-zearalanol, and β-zearalanol were not detected in any of the samples. © 2015 by the authors; licensee MDPI, Basel, Switzerland.
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| 10.
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Hayakawa, Kazuichi ; Onoda, Yu ; Tachikawa, Chihiro ; Hosoi, Shinzo ; Yoshita, Morio ; Chung, Sang Woon ; Kizu, Ryoichi ; Toriba, Akira ; Kameda, Takayuki ; Tang, Ning
概要:
Estrogenic/antiestrogenic activities of 14 polycyclic aromatic hydrocarbons (PAHs) and 63 monohydroxylated PAHs (OHPAHs)
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having 2 to 6 rings were evaluated by yeast two-hybrid assay expressing human estrogen receptor α. Relative effective potencies of estrogenic and antiestrogenic activities were calculated as the inverse values of the relative concentration of the test compound that gave the same activities of E2 and 4-hydroxytamoxifen, respectively. PAHs did not show any estrogenic/antiestrogenic activity, but several OHPAHs having 3 to 5 rings showed activities. Especially, OHPAHs having 4 rings such as 3-, 4- and 10-hydroxybenz[a]anthracenes (3-, 4- and 10-OHBaAs) and 2-hydroxychrysene (2-OHCh) showed strongly estrogenic activity. Several other OHPAHs having 4 rings such as 2- and 3-hydroxybenzo[c]phenanthrenes (2-, 3- OHBcPhs), 2-OHBaA and 3-OHCh showed strongly antiestrogenic activity. The length-to-breadth (L/B) ratios of the rectangular van der Walls planes surrounding the ring molecules of estrogenic OHPAHs were in the narrow range from 1.599 to 1.734. The distances between the oxygen atom of the phenol group and farthest hydrogen atom (O-H distance) of the estrogenic OHPAHs ranged from 10.825 A° to 11.738 A°. The L/B ratios and O-H distances of antiestrogenic OHPAHs were in the wider ranges from 1.277 to 1.734 and from 8.47 A° to 11.681 A°, respectively. The partial charges (atomic unit) of the phenol group of both estrogenic and antiestrogenic OHPAHs were in the range from 0.250 atmic unit (au) to 0.253 au. The similarity of these values to those of E2 and diethylstilbestrol suggested that the compositions of estrogenic OHPAHs were similar to them and that the compositional conditions of estrogenic OHPAHs were much smaller than those of antiestrogenic OHPAHs. These results raise the possibility of predicting the estrogenic/antiestrogenic activities of OHPAHs from their structural characteristics, although using only the above three parameters might not be enough for accurate estimations.
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