研究者業績

田崎 弘之

タザキ ヒロユキ  (Hiroyuki Tazaki)

基本情報

所属
日本獣医生命科学大学 獣医学部 獣医学科 教授 (研究科長)
学位
博士(農学)

J-GLOBAL ID
200901011481740045
researchmap会員ID
5000081034

受賞

 1

論文

 87
  • Hiroshi M Ueno, Touko Sato, Satoshi Higurashi, Hiroyuki Tazaki, Yasuhiro Toba
    Current developments in nutrition 6(6) nzac093 2022年6月  
    Background: Maternal diet and sociodemographic factors influence xanthophyll concentration and composition in human milk. However, the importance of dietary patterns regarding the intake of fruits, vegetables, and xanthophylls remains unclear. Objective: The aim was to determine the composition of xanthophylls in the human milk of Japanese mothers and explore associations of xanthophylls with dietary and sociodemographic factors. Methods: This cross-sectional study was conducted in the early phase of the Japanese Human Milk Study. Xanthophyll content was measured using liquid chromatography at 30-36 d postpartum. Maternal intake of foods, nutrients, and dietary supplements was estimated using a food-frequency questionnaire. Linear regression models were established using xanthophylls, maternal diet, and sociodemographic factors. Results: Xanthophyll concentrations were measured in human milk from 118 mothers. The xanthophyll concentration varied among individuals. The median (IQR) concentrations of lutein, zeaxanthin, and β-cryptoxanthin were 65.6 ng/mL (51.6-103.4 ng/mL), 18.6 ng/mL (12.9-25.8 ng/mL), and 15.6 ng/mL (9.0-26.0 ng/mL), respectively. In multivariate models, the lutein concentration was associated independently with dietary green vegetables, exclusive breastfeeding, and education (r 2 = 0.153 for the model; β ± SE: 0.468 ± 0.198, 25.048 ± 10.222, and 13.460 ± 6.774; standardized β = 0.210, 0.217, and 0.175; P = 0.019, 0.016, and 0.049 for dietary green vegetables, exclusive breastfeeding, and education, respectively). For zeaxanthin, exclusive breastfeeding was the most appropriate predictor (r 2 = 0.085; β ± SE: 7.811 ± 3.300; standardized β = 0.218; P = 0.020). The highest predictive power for human milk β-cryptoxanthin was obtained with dietary β-cryptoxanthin (r 2 = 0.258; β ± SE: 0.089 ± 0.015; standardized β = 0.468; P < 0.001), attributed to maternal citrus intake. Conclusions: β-Cryptoxanthin in human milk was the xanthophyll most influenced by the maternal diet in Japanese women. The β-cryptoxanthin concentration in human milk was reflected by the maternal β-cryptoxanthin intake, mainly attributed to Japanese citrus consumption. This trial was registered in the Japanese Clinical Trials Registry (https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000017649) as UMIN000015494.
  • 寺師 宗嵩, 佐藤 稲子, 片山 欣哉, 田村 好, 宮本 汐里, 栃木 裕貴, 畠山 仁, 呰上 大吾, 田崎 弘之
    日本獣医学会学術集会講演要旨集 164回 [IO-44] 2021年9月  
  • 田村 好, 片山 欣哉, 佐藤 稲子, 寺師 宗嵩, 宮本 汐里, 栃木 裕貴, 畠山 仁, 呰上 大吾, 田崎 弘之
    日本獣医学会学術集会講演要旨集 164回 [IO-45] 2021年9月  
  • Ayaka Domon, Kentaro Katayama, Touko Sato, Yuki Tochigi, Hiroyuki Tazaki, Hiroetsu Suzuki
    PLoS ONE 16(5 May) 2021年5月  
    Background Sodium-glucose cotransporter 2 (SGLT2) inhibitors are widely used to reduce hyperglycemia. The present study investigated the effects of a SGLT2 inhibitor, empagliflozin, on hyperglycemia in a novel rat model of non-obesity type 2 diabetes with enlarged kidney (DEK). Methods Male DEK rats with non-fasting blood glucose concentrations ≤300 mg/dl and >300 mg/dl were classified as nondiabetic and diabetic, respectively. Groups of nondiabetic (control) and diabetic (DM-cont) rats were fed standard chow for 12 weeks, whereas another group of diabetic (DM-empa) rats was fed standard chow containing empagliflozin (300 mg/kg/ day) for 12 weeks. Blood glucose, body weight, glucose tolerance, food and water intake, urinary volume, plasma and urinary biochemical parameters, and bone mineral density were measured, and their kidneys and pancreas histologically analyzed. Results Treatment with empagliflozin reduced blood glucose concentration and food intake in diabetic rats, but inhibited loss of adeps renis and led to body weight gain. Empagliflozin attenuated polyuria and polydipsia but increased plasma concentrations of total cholesterol, sodium and total protein toward normal level. Empagliflozin also significantly reduced urinary excretion of proteins and electrolytes and restored bone mineral density and plasma concentrations of valine and isoleucine to normal levels. Moreover, dilation of renal tubules and kidney enlargement were not attenuated in the DM-empa group. Conclusion The response of DEK rats to empagliflozin differed from that of other diabetic animal models, suggesting that DEK rats have unique characters for studying and evaluating the multiple biological effects of SGLT2 inhibitors. These findings also indicted that empagliflozin could ameliorate systemic metabolism and improve renal tubule function in diabetic condition.
  • Ryota Akabane, Touko Sato, Atsushi Sakatani, Mizuki Ogawa, Masayoshi Nagakawa, Hirosumi Miyakawa, Yuichi Miyagawa, Hiroyuki Tazaki, Naoyuki Takemura
    Journal of Veterinary Medical Science 82(4) 446-451 2020年  
    Information regarding the pharmacokinetics of oral sildenafil in dogs with pulmonary hypertension is limited. In this study, we examined the pharmacokinetics of oral sildenafil in a canine model of chronic embolic pulmonary hypertension (CEPH). The CEPH model was developed by repeatedly injecting microspheres into the pulmonary arteries. The pharmacokinetics of oral sildenafil at 1, 2 and 4 mg/kg was evaluated using four dogs with pulmonary hypertension in the fasted state. The plasma concentrations of sildenafil were determined using high-performance liquid chromatography, and pharmacokinetic parameters were calculated using a noncompartmental analysis. Sildenafil was well tolerated in this study. Proportional increments in the maximum plasma concentration and area under the curve extrapolated to infinity at drug doses of 1, 2 and 4 mg/kg were detected using a power model analysis. No significant differences were observed among the three doses in the time to maximum plasma concentration. The mean residence time and elimination half-life were slightly but significantly higher at a dose of 4 mg/kg than at a dose of 1 mg/kg.
  • Michishita M, Saito N, Nozawa S, Furumoto R, Nakagawa T, Sato T, Ochiai K, Azakami D, Katayama K, Nakahira R, Tazaki H, Machida Y, Ishiwata T
    The Journal of veterinary medical science 81(9) 1238-1248 2019年7月  査読有り
  • 塩住 友哉, 赤羽根 僚太, 佐藤 稲子, 酒谷 篤, 小川 実月, 宮川 寛済, 長川 雅佳, 宮川 優一, 田崎 弘之, 竹村 直行
    日本獣医麻酔外科学雑誌 50(Suppl.1) 318-318 2019年6月  
  • 赤羽根 僚太, 佐藤 稲子, 小川 実月, 長川 雅佳, 宮川 寛済, 酒谷 篤, 宮川 優一, 田崎 弘之, 竹村 直行
    日本獣医麻酔外科学雑誌 50(Suppl.1) 323-323 2019年6月  
  • 田崎 弘之
    Journal of Veterinary Medical Science 80(8) 1228-1232 2018年8月  査読有り
  • R. Akabane, T. Sato, A. Sakatani, Y. Miyagawa, H. Tazaki, N. Takemura
    Journal of Veterinary Pharmacology and Therapeutics 41(3) 457-462 2018年6月1日  
    Basic information related to the pharmacokinetics of sildenafil in dogs is scarce. This study aimed to describe the pharmacokinetic properties of oral sildenafil and determine the effect of feeding and dose proportionality. The effect of feeding on pharmacokinetics of sildenafil (1 mg/kg) was investigated using a crossover study with six dogs. In addition, the dose proportionality of sildenafil ranging 1–4 mg/kg was evaluated using five dogs in the fasted states. The plasma concentrations of sildenafil were determined using high-performance liquid chromatography, and pharmacokinetic parameters were calculated using a noncompartmental analysis. Sildenafil administrations were well tolerated in all studies. Feeding reduced the area under the curve extrapolated to infinity (AUCinf) and the maximum plasma concentration (Cmax) significantly. The elimination half-life (T1/2) did not differ between the fasted and the fed states. For dose proportionality, nonproportional increases in AUCinf and Cmax at 1–4 mg/kg doses were detected by a power model analysis.
  • Michishita Masaki, Saito Namika, Nozawa Satoshi, Furumoto Rina, Nakagawa Takayuki, Sato Touko, Katayama Kinya, Tazaki Hiroyuki, Ishiwata Toshiyuki, Takahashi Kimimasa
    CANCER SCIENCE 109 266 2018年1月  査読有り
  • 赤羽根僚太, 佐藤稲子, 酒谷篤, 宮川優一, 田崎弘之, 竹村直行
    日本獣医麻酔外科学雑誌 48(Supplement 2) 237 2017年11月20日  
  • 矢野健人, 赤羽根僚太, 佐藤稲子, 酒谷篤, 宮川優一, 田崎弘之, 竹村直行
    日本獣医麻酔外科学雑誌 48(Supplement 2) 237 2017年11月20日  
  • 佐藤稲子, 片山欣哉, 関根舞, 鈴木清文, 神志那弘明, 田崎弘之
    JSBMS Letters 42(Supplement) 78 2017年8月25日  
  • 望月眞理子, 銀梓, 佐藤稲子, 石本史子, 美濃輪史子, 石岡克己, 田崎弘之, 大久保公裕
    Veterinary Nursing 21(1) 62 2016年6月20日  
  • Mariko Mochizuki, Noriyuki Hayakawa, Fumiko Minowa, Akihiro Saito, Katsumi Ishioka, Fukiko Ueda, Kimihiro Okubo, Hiroyuki Tazaki
    ENVIRONMENTAL MONITORING AND ASSESSMENT 188(4) 6 2016年4月  
    In this study, iodine and thyroxin (T4) concentrations in the serum of 69 horses were investigated. Higher iodine concentrations were obtained from the horses housed in Chiba Prefecture. In contrast, T4 concentrations of horses at Shizuoka Prefecture were higher than those of horses at Chiba Prefecture. There was a significant correlation (r = 0.643, P &lt; 0.001) between the iodine and T4 concentrations of horses at Saitama and. Shizuoka prefectures. Although a significant correlation (r=0.794, P &lt; 0.001) was also observed in the investigation of all horses at Chiba Prefecture, the distribution area of the data was separated from the data of horses housed in Saitama and Shizuoka prefectures. A higher iodine concentration in the environment is expected in the sampling area at Chiba Prefecture. Thus, it was suggested that the concentrations of iodine in the serum of horses are influenced by geological differences. It was thought that equine senim is a useful sample for monitoring.
  • Satoshi Nozawa, Touko Sato, Kinya Katayama, Katsumi Ishioka, Toshinori Sako, Toshiro Arai, Hiroyuki Tazaki
    VETERINARY JOURNAL 207 184-187 2016年1月  
    In dogs, hyperadrenocorticism (HAC) is associated with insulin resistance and diabetes does progress with HAC. There are significant differences in the transcriptomic and proteomic patterns of activated T cells, which parallel the findings in muscle tissues. The aim of this study was to assess how glucocorticoids affect intracellular metabolites in canine peripheral blood mononuclear cells (CnPBMCs) using dexamethasone. A total of 96 metabolites were identified by capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS). After incubation with dexamethasone, the metabolites glucose 1-phosphate, glucose 6-phosphate, fructose 6-phosphate, sedoheptulose 7-phosphate and acetyl-CoA were significantly increased. However, ATP, CTP, dATP, pyruvic acid and NADP(+) were significantly decreased. These results show that a glucocorticoid reduces the catabolic reaction of glucose and accordingly decreases the glucose requirements of CnPBMCs. (C) 2015 Elsevier Ltd. All rights reserved.
  • Megumi Fujiwara, Nobuko Mori, Touko Sato, Hiroyuki Tazaki, Shingo Ishikawa, Ichiro Yamamoto, Toshiro Arai
    BMC VETERINARY RESEARCH 11(1) 2015年8月  
    Background: Obesity and overweight have been frequently observed in dogs and cats in recent years as in humans. The compositions of fatty acids (FAs) in the accumulated lipids in tissues of obese animals may have important roles in the process and mechanisms related to the onset of metabolic disorders. The purpose of this study was to evaluate the effects of a high fat (HF) diet, which contained a higher proportion of saturated FAs, on FA metabolism and distribution in obese cats. Cats (N = 12) were divided into control diet group (crude fat; 16.0 %) (n = 4) or a high fat (HF) diet group (crude fat; 23.9 %) (n = 8). The HF diet contained up to 60 % of calories from fat and was rich in stearic acid. Blood samples were collected at 0, 2, 4 and 6 weeks after the feeding. Adipose and liver tissues were collected at the 6th week after feeding. We performed analysis of histological findings and fatty acid composition in serum and tissues. Results: Body weights of the cats significantly increased in the HF group. The increased activities of hepatic enzymes and the accumulation of lipid droplets were found in hepatocytes in the HF group at the 6th week after feeding. In this study, the stearic acid (C18:0)-rich HF diet contained less oleic acid (C18:1n-9) and more linoleic acid (C18:2n-6) than the control. However, the composition of oleic acid in the liver was higher, and those of stearic acid and linoleic acid were lower in the HF group at the 6th week after feeding. The higher oleic acid: stearic acid ratio suggests an increase in the conversion from saturated FA to mono-unsaturated FAs, which may reflect the hepatic storage of FAs as a relatively harmless form. Conclusion: The stearic acid-rich HF diet increased hepatic lipid accumulation accompanied by the increased of hepatic oleic acid, increased serum oleic acid and activation of hepatic enzymes. These findings could be an important sign of early stages of dyslipidemia and hepatic damage. Also, the higher oleic acid: stearic acid ratio might be related to the increased activity of SCD-1, which suggests that the stearic acid-rich HF diet evoked hepatic lipogenesis in the feline liver.
  • Satoshi Nozawa, Hitomi Oda, Ran Akiyama, Kaori Ueda, Kaori Saeki, Saori Shono, Natsuki Maruyama, Atsuki Murata, Hiroyuki Tazaki, Akihiro Mori, Yutaka Momota, Daigo Azakami, Toshinori Sako, Katsumi Ishioka
    JOURNAL OF VETERINARY MEDICAL SCIENCE 76(8) 1177-1182 2014年8月  
    Hyperadrenocorticism (HAC) is a common endocrine disorder in dogs, in which excess glucocorticoid causes insulin resistance. Disturbance of insulin action may be caused by multiple factors, including transcriptional modulation of insulin signal molecules which lie downstream of insulin binding to insulin receptors. In this study, gene expressions of insulin signal molecules were examined using neutrophils of the HAC dogs (the untreated dogs and the dogs which had been treated with trilostane). Insulin receptor substrate (IRS)-1, IRS-2, phosphatidylinositol 3-kinase (P13-K), protein kinase B/Akt kinase (Akt)-2 and protein kinase C (PKC)-lambda were analyzed in the HAC dogs and compared with those from normal dogs. The IRS-1 gene expressions decreased by 37% and 35% of the control dogs in the untreated and treated groups, respectively. The IRS-2 gene expressions decreased by 61% and 72%, the P13-K gene expressions decreased by 47% and 55%, and the Akt-2 gene expressions decreased by 45% and 56% of the control dogs, similarly. Collectively, gene expressions of insulin signal molecules are suppressed in the HAC dogs, which may partially contribute to the induction of insulin resistance.
  • Fumihito Takahashi, Mariko Mochizuki, Takuya Yogo, Katsumi Ishioka, Norio Yumoto, Toshinori Sako, Fukiko Ueda, Masahiro Tagawa, Hiroyuki Tazaki
    JOURNAL OF VETERINARY MEDICAL SCIENCE 76(4) 569-572 2014年4月  
    To understand the effects of silicon (Si) in the urine with respect to the formation of urinary stones, the distribution of Si in urine was observed. Urine samples from cats with urolithiasis (n=10) and healthy cats (n=15) were used. The concentration of Si in the cats with urolithiasis was significantly higher (P&lt;0.001). A significant correlation (P&lt;0.05) was observed between the concentration of Si and those of other elements, such as calcium, magnesium, phosphorus, potassium and iron, only in the urine of the healthy cats. The distribution of elements in the urine differed between the cats with urolithiasis and the healthy cats. The Si concentration and its relationship with other elements were suggested to be useful biomarkers for urolithiasis in cats.
  • 高橋 公正, 齋藤 那美香, 片山 欣哉, 近内 将記, 榊 基, 黒田 伸彦, 高橋 淳, 塚田 晃三, 道下 正貴, 田崎 弘之
    日本獣医学会学術集会講演要旨集 156回 209-209 2013年8月  
  • K. Katayama, T. Sato, T. Arai, H. Amao, Y. Ohta, T. Ozawa, P. R. Kenyon, R. E. Hickson, H. Tazaki
    JOURNAL OF ANIMAL PHYSIOLOGY AND ANIMAL NUTRITION 97(1) 119-125 2013年2月  
    Simple liquid chromatographymass spectrometry (LC-MS) was applied to non-targeted metabolic analyses to discover new metabolic markers in animal plasma. Principle component analysis (PCA) and partial least squaresdiscriminate analysis (PLS-DA) were used to analyse LC-MS multivariate data. PCA clearly generated two separate clusters for artificially induced diabetic mice and healthy control mice. PLS-DA of time-course changes in plasma metabolites of chicks after feeding generated three clusters (pre- and immediately after feeding, 0.53 h after feeding and 4 h after feeding). Two separate clusters were also generated for plasma metabolites of pregnant Angus heifers with differing live-weight change profiles (gaining or losing). The accompanying PLS-DA loading plot detailed the metabolites that contribute the most to the cluster separation. In each case, the same highly hydrophilic metabolite was strongly correlated to the group separation. The metabolite was identified as betaine by LC-MS/MS. This result indicates that betaine and its metabolic precursor, choline, may be useful biomarkers to evaluate the nutritional and metabolic status of animals.
  • Fumihito Takahashi, Mariko Mochizuki, Touko Sato, Kinya Katayama, Paul R. Kenyon, Stephen T. Morris, Peter D. Kemp, Takeyuki Ozawa, Fukiko Ueda, Hiroyuki Tazaki
    ANIMAL SCIENCE JOURNAL 84(6) 496-501 2013年  
    The establishment of a classification system for domestic animals on consumed feed stuff is thought to be important from both a hygiene and market point of view. We collected plasma samples of Romney lambs (Ovis aries) which were fed one of the following: a herb-clover mix (n=10) which included chicory, red clover, white clover and plantain; a plant-grass mix (n=10) which included plantain, ryegrass and white clover; or a grass mix (n=10) which included ryegrass and white clover. A total of 20 elements in plasma samples obtained from the lambs were analyzed using inductively coupled plasma mass spectrometry. The data were then analyzed by principal component analysis. The lambs were divided into three groups on a score plot depending on the different feed conditions. Furthermore, discriminant analyses of the elements were examined, using linear discriminant analysis with forward stepwise regression. This discriminant function correctly classified the samples from each group. The accuracy of classification of each group, as shown by 10-fold cross-validation, proved the effectiveness of the established discriminant function. It is concluded that using linear discriminant analysis might be a useful tool for the validation of elements from plasma in lambs grown in different conditions.
  • Megumi Fujiwara, Toko Sato, Hiroyuki Tazaki, Ichiro Yamamoto, Koh Kawasumi, Toshiro Arai
    Asian Journal of Animal and Veterinary Advances 8(4) 639-646 2013年  
    Hyperlipidemia refers to increase of triglyceride (TG) and/or total cholesterol (T-cho) in blood. Fatty Acids (FAs) have important roles in the lipid metabolism. The aim of this study was to determine the FA composition of plasma lipid fractions in dogs with hyperlipidemia and to evaluate the FA composition as a new diagnostic marker for obesity at early stage. Thirty-nine dogs were classified into healthy or hyperlipidemia based on the criteria to diagnose hyperlipidemia. The blood biochemical values, such as TG, T-cho, glucose, insulin, adiponectin and Non-Esterified Fatty Acid (NEFA) were measured. FA composition profile was performed on GC/MS system. The values of plasma TG, insulin and NEFA of the hyperlipidemia group were significantly higher than that of control group. Hyperlipidemia group tended to show lower concentration of adiponectin. It was found that only the levels of TG and NEFA, but not T-cho increased significantly in early stage of hyperlipidemia. In hyperlipidemia group, percentages of myristic acid (C14:0), parmitoleic acid (C16:1) and oleic acid (C18:1) increased in total FAs. And the percentage of C18:1 increased in NEFA. Indeed, the higher level of insulin and lower adiponectin concentration were seen in hyperlipidemia group. These results suggest that appearance of insulin resistance may be the result of increases of certain FAs in early stage of insulin resistance. © 2013 Academic Journals Inc.
  • Kinya Katayama, Masako Miyoshi, Kensuke Nabeta, Hiroyuki Tazaki
    PHYTOCHEMISTRY LETTERS 5(4) 761-765 2012年12月  
    The in vitro cultured liverwort Jungermannia subulata produces the unique molecule subulatin. In this study, we examined the incorporation of [1-C-13] nd [1,2-C-13(2)]glucose, [2-C-13] arabinose, [2-C-13] caffeic acid, and [1-C-13] phenylalanine into subulatin. The trilobatinoic acid C unit of subulatin incorporated C-13 atoms from [1-C-13] and [1,2-C-13(2)] glucose and from [2-C-13] arabinose but not from any other of the other precursors. Based on these results and labeling patterns, the trilobatinoic acid C unit of subulatin appears to be biosynthesized from arabinose-5-phosphate and phosphoenolpyruvate. (c) 2012 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.
  • 藤原めぐみ, 佐藤稲子, 田崎弘之, 山本一郎, 川角浩, 新井敏郎
    予防動物医学 4(2) 63-58 2012年10月  査読有り
  • Yohei Miki, Akihiro Mori, Noriyuki Hayakawa, Tomoe Niki, Hitomi Oda, Kaori Saeki, Toko Sato, Hiroyuki Tazaki, Katsumi Ishioka, Toshiro Arai, Toshinori Sako
    JOURNAL OF VETERINARY MEDICAL SCIENCE 73(9) 1117-1126 2011年9月  
    1,5-anhydro-D-glucitol (1,5AG) is a pyranoid polyol compound found in human circulating blood. Myo-inositol (MI) is a stereoisomer of inositol and serves as a precursor of inositol phospholipids. I,5AG and MI are filtered by the glomerulus and almost completely reabsorbed through the renal tubules. However, under hyperglycemic conditions, reabsorption through the renal tubules is competitively inhibited because the structures of I,5AG and MI resemble that of glucose. In this study, we investigated the kinetics of serum and urine 1,5AG and MI levels in healthy dogs. We demonstrated that 1,5AG and MI exist in canine serum and urine by gas chromatography-mass spectrometry. Under continuous hyperglycemic conditions, the serum 1,5AG concentration in healthy dogs decreased while the serum MI concentration remained unchanged. Urinary excretion of 1,5AG and MI increased significantly after blood glucose concentrations reached 200 to 220 mg/d/. A significant negative correlation was observed between serum 1,5AG and glucose concentrations during hyperglycemia. However, no significant correlation was observed between serum MI and glucose concentrations. In this study, we demonstrated that serum and urine 1,5AG and MI levels were changed by blood glucose concentrations. The serum I,5AG concentration was decreased by continuous hyperglycemia. However, the serum MI concentration does not reflect hyperglycemia.
  • T. Sato, A. Toyoshima, T. Hiraki, Y. Ohta, K. Katayama, T. Arai, H. Tazaki
    BRITISH POULTRY SCIENCE 52(2) 273-277 2011年  
    1. The objective of this study was to determine the effects of the gluconeogenesis inhibitor metformin on 21-d old chickens. The following parameters were measured in the liver and kidney: plasma glucose, plasma mannose, enzyme activities and mRNA expression levels of glucose-6-phosphatase (G6Pase), and phosphoenolpyruvate carboxykinase (PEPCK). 2. Chickens were divided into two groups, and received either metformin (300 mg/kg body weight) or water. Plasma glucose and mannose concentrations were analysed by high performance liquid chromatography (HPLC). G6Pase and PEPCK activities were determined by glucose 6-phosphate and malic acid substrate methods, respectively. The expression levels of mRNA were determined by real-time PCR. 3. Plasma glucose and mannose reached their lowest concentrations 1 h after metformin administration. At 0 center dot 5 h-1 h after metformin administration, the enzyme activities and mRNA expression levels of G6Pase and PEPCK reached their lowest point in the kidney and their highest point in the liver. The decrease observed in the kidney may have been associated with reductions in both plasma glucose and mannose concentrations. 4. In conclusion, the effect of metformin on the kidney of chickens is similar to its effect in mammals. In contrast, no suppression of enzyme activity or mRNA expression was observed in chicken liver. Therefore, the mode of action of metformin, via AMPK activation, may be different in the chicken liver.
  • J. S. Jeong, J. H. Lee, Y. Simizu, H. Tazaki, H. Itabashi, N. Kimura
    ANIMAL FEED SCIENCE AND TECHNOLOGY 162(3-4) 144-148 2010年12月  
    The objective of this study was to determine the effect of deoxynivalenol (DON) on in vitro rumen fermentation by assessing pH ammonia-N total gas volatile fatty acid (VFA) production and DON degradation under the context of two different carbon sources (corn starch or cellulose) Fifty millilitre of ruminal fluid buffer (1 1) was incubated for up to 6 h with four possible treatments corn starch 1 5 g corn starch 1 5 g+ DON at 40 mg/kg dry matter (DM) cellulose 1 5 g and cellulose 1 5 g + DON at 40 mg/kg DM Our results indicate that carbon source appears to markedly influence all rumen fermentative parameters (P&lt;005) whereas DON negatively Impacted certain aspects of rumen fermentative capacity such as ammonia-N and total gas production especially acetate and propionate production having been reduced (P&lt;0 01) Therefore it may be possible for carbon source to influence and limit the degree upon which DON s effects are exerted DON degradation rate was especially influenced by carbon source context (P=0 0105) with cellulose leading to a higher rate of DON degradation than that of corn starch This would indicate that concentrate/forage ratio in the diet may have an effect on DON degradation (C) 2010 Published by Elsevier B V
  • A. Mori, T. Sato, P. Lee, M. Furuuchi, H. Tazaki, K. Katayama, H. Mizutani, T. Sako, T. Arai
    VETERINARY RESEARCH COMMUNICATIONS 33(5) 439-451 2009年6月  
    Circulating levels of monosaccharides can act as a reflection of systemic glucose/ energy metabolism. Characteristic changes observed in these levels can be seen in patients with diabetes and other metabolic disorders. There have been a few reports describing the significance of mannose metabolism as an energy source under physiological and pathological conditions. However, the relationship between circulating levels of mannose and the pathophysiology of diabetes mellitus are unknown in dogs. This study examined circulating levels of mannose between healthy control and diabetic dogs and evaluated the clinical significance of mannose levels in dogs. Diabetic dogs demonstrated a higher circulating level of mannose in comparison to normal healthy control dogs. Plasma mannose was positively correlated with plasma glucose and fructosamine, respectively. Interestingly, plasma mannose levels were affected by plasma insulin levels. In the context of feeding and glucose tolerance tests, plasma mannose levels responded to changes in circulating insulin levels. Circulating plasma mannose levels decreased after feeding in both control and diabetic animals in spite of observed insulin level differences. However, when glucose tolerance tests were given, a positive correlation between mannose levels and insulin levels was observed. Therefore, plasma mannose levels obtained via glucose tolerance testing may be used as a new diagnostic method for evaluating insulin resistance or deficiency in diabetic dogs.
  • T. Sako, A. Mori, P. Lee, T. Sato, H. Mizutani, T. Takahashi, Y. Kiyosawa, H. Tazaki, T. Arai
    VETERINARY RESEARCH COMMUNICATIONS 33(5) 473-479 2009年6月  
    Measurements of serum fructosamine, glycated hemoglobin, and glycated albumin (GA) complement serum glucose concentration for better management of diabetes mellitus (DM). Especially, the serum fructosamine test has long been used for diagnosing and monitoring the effect of treatment of DM in dogs. However, fructosamine tests are currently not performed in veterinary medicine in Japan. GA and fructoasmine levels have been shown to strongly correlate. However, the clinical implications of using GA remain to be elucidated. Therefore, the purpose of the current study was threefold: 1) Determine whether GA% is altered by acute hyperglycemia in normal dogs, simulating stress induced hyperglycemia; 2) Demonstrate that GA% does not dynamically change with diurnal variation of blood glucose concentration in diabetic dogs; and 3) Investigate whether GA% is capable of providing an index of glycemic control for 1-3 weeks in diabetic dogs as is the case with diabetic human patients. Our study demonstrated that serum GA% remains very stable and unaltered under acute hyperglycemic conditions (intravenous glucose injection) and in spite of diurnal variation of blood glucose concentration. Furthermore, serum GA% can reflect long-term changes (almost 1-3 weeks) in blood glucose concentration and the effect of injected insulin in diabetic dogs.
  • Y. Tanaka, A. Mori, H. Tazaki, S. Imai, J. Shiina, A. Kusaba, T. Ozawa, T. Yoshida, N. Kimura, T. Hayashi, P. R. Kenyon, H. Blair, T. Arai
    RESEARCH IN VETERINARY SCIENCE 85(1) 17-21 2008年8月  
    Plasma metabolite concentrations and activities of enzymes related to energy metabolism in plasma, peripheral leukocytes and liver of pregnant Romney ewes with restricted feeding were measured to assess those metabolites and enzymes as indicators for evaluating metabolic conditions in the ewes. The body weights and plasma lactate concentrations of the low-feeding ewes (about 1.0 times maintenance) were significantly lower than those of the high-feeding ewes (about 1.5 times maintenance). There were no significant differences ill plasma protein, glucose, triglyceride, cholesterol, pyruvate and immunoreactive insulin concentrations and plasma and leukocyte enzyme activities between both groups. Hepatic malate dehydrogenase activities were significantly higher and hexokinase activities were significantly lower in the low-feeding ewes than in the high-feeding ewes. Restricted feeding could maintain pregnancy and some plasma metabolites and peripheral leukocyte enzymes may be useful indicators for evaluating metabolic changes in ewes. (C) 2007 Elsevier Ltd. All rights reserved.
  • T. Sato, K. Katayama, T. Arai, T. Sako, H. Tazaki
    RESEARCH IN VETERINARY SCIENCE 84(1) 26-29 2008年2月  
    Serum mannose and glucose concentrations in dogs before and after eating a meal were determined simultaneously with a recently established HPLC method combined with a UV and fluorescence detection system of p-aminobenzoic acid ethyl ester (ABEE)-derivatized monosaccharides. In this newly established HPLC method, detection limits were 0.09 mu mol/L for mannose and 0.04 mmol/L for glucose. Linearity of peak areas vs. amounts of mannose and glucose in the range of 0.27-320 mu mol/L and 0.13-64 mmol/L were observed, respectively. The value of the glucose content measured by the HPLC method was in good agreement with that of the commonly used enzymatic method (control). Serum glucose concentrations in dogs 90 min after the meal were almost the same as those before the meal, whereas serum mannose concentrations decreased significantly after the meal. This HPLC method may be useful for determination of monosaccharides in animal blood. (C) 2007 Elsevier Ltd. All rights reserved.
  • A. Mori, P. R. Kenyon, N. Mori, I. Yamamoto, Y. Tanaka, N. Suzuki, H. Tazaki, T. Ozawa, T. Hayashi, R. E. Hickson, S. T. Morris, H. Blair, T. Arai
    VETERINARY RESEARCH COMMUNICATIONS 32(2) 159-166 2008年2月  
    Metabolite and immunoreactive insulin (IRI) concentrations, energy metabolism related enzymes activities and peripheral blood mononuclear cell (PBMC) populations were measured in blood of pregnant Angus heifers with differing liveweight change profiles (gaining or losing), in New Zealand to investigate the meanings of those parameters in the restricted feeding beef heifers. Beef heifers losing liveweight (-412 g/day) showed significantly lower concentrations of plasma IRI, and higher concentrations of plasma free fatty acid (FFA) than heifers gaining liveweight (483 g/day). The cytosolic and mitochondrial malate dehydrogenase (MDH) activities and MDH/lactate dehydrogenase (M/L) ratio in leukocytes of the liveweight losing heifers were significantly higher than those the liveweight gaining heifers. Percentages of cluster of differentiation (CD) 3 positive cells and natural killer (NK) cells in PBMC decreased significantly in the liveweight losing heifers compared to those in the liveweight gaining heifers. Plasma IRI and FFA concentrations, leukocyte cytosolic and mitochondrial MDH activities and CD3 positive and NK cell populations may be useful markers to evaluate metabolic conditions and immunity in the restricted feeding beef heifers.
  • T. Sato, S. Soeda, Y. Ohta, K. Katayama, T. Arai, H. Tazaki
    BRITISH POULTRY SCIENCE 49(6) 731-735 2008年  
    1. The oral administration of glucose or dietary glucose reduces fasting plasma mannose concentrations in mammals. On the other hand, there have been no reports on plasma mannose levels in birds. We have analysed chicken plasma mannose and glucose by an original high-performance liquid chromatography (HPLC) method, together with plasma non-esterified fatty acid (NEFA) concentrations in chickens. 2. Plasma glucose concentrations of chickens did not differ among three different age groups (0, 18 and 150 d). However, the plasma mannose concentrations of chicks at the age of 0 d were higher than those of chickens at the ages of 18 and 150 d. 3. At the age of 18 and 150 d, plasma glucose concentrations were elevated and plasma mannose and NEFA concentrations were decreased after regular feeding, compared to fasting levels.
  • Satoru Watanabe, Ken Hashimoto, Hiroyuki Tazaki, Yuzuri Iwamoto, Naoko Shinohara, Kazue Satoh, Hiroshi Sakagami
    FOOD SCIENCE AND TECHNOLOGY RESEARCH 13(4) 366-371 2007年11月  
    Four phenolic compounds were isolated from Japanese butterbur (Petasites japonicus) by preparative RP-HPLC technique, and were identified as chlorogenic acid (CGA), fukinolic acid (FA), 3,5-dicaffeoyl quinic acid, and 3,4,5-tricaffeoyl quinic acid. Since the antioxidant activity of FA among these four compounds has not been reported in detail, we investigated the scavenging activity of FA against several active oxygens and radicals, compared with CGA, gallic acid (GA) and epigallocatechin gallate (EGCG), using ESR spectroscopy. The order of potency of scavenging superoxide anion, nitric oxide (NO) and DPPH was EGCG&gt;FA&gt; CGA. The order of potency of scavenging hydroxyl radical was EGCG&gt;FA&gt;GA. FA inhibited the lipopolysaccharide-stimulated NO production and inducible NO synthase protein and mRNA expression by mouse macrophage-like cells Raw 264.7 more potently than CGA. The present study suggests the usefulness of FA as an antioxidant.
  • Kinya Katayama, Kazuko Shimazaki, Hiroyuki Tazaki, Yasuhiro Hasa, Masako Miyoshi, Hiroyuki Koshino, Tatsuo Furuki, Kensuke Nabeta
    BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 71(11) 2751-2758 2007年11月  
    New clerodane-type diterpenes, designated as parvitexins A (1)-E (5), were isolated from the in vitro-cultured liverwort, Scapania parvitexta. These compounds were determined to be monoacetylated clerodane-type diterpenes based on spectroscopic evidence.
  • A. Mori, S. Urabe, M. Asada, Y. Tanaka, H. Tazaki, I. Yamamoto, N. Kimura, T. Ozawa, S. T. Morris, R. Hickson, P. R. Kenyon, H. Blair, C. B. Choi, T. Arai
    JOURNAL OF VETERINARY MEDICINE SERIES A-PHYSIOLOGY PATHOLOGY CLINICAL MEDICINE 54(7) 342-345 2007年9月  
    Concentrations of metabolites and immunoreactive insulin (IRI) and activities of enzymes related to energy metabolism were measured in plasma of Korean and Japanese beef cattle, which were raised by the indoor feeding system programmed to feed larger amount of roughage in their growing periods and larger amount of concentrate diet in their finishing periods (Japanese feeding system), and grazing New Zealand beef cattle. By the Japanese beef grading system, Korean and Japanese beef cattle showed high beef quality score, average grade 3.3 and 3.6, respectively. The plasma free fatty acid and lactate concentrations and lactate dehydrogenase (LDH), malate dehydrogenase (MDH) and aspartate aminotransferase (AST) activities in Korean beef cattle were significantly higher than those in Japanese beef cattle. The plasma lactate concentration in Korean beef cattle was 8.40 mmol/l, which was similar to the values observed in lactic acidosis. The higher activities of plasma LDH, MDH and AST may indicate slight liver damage by slightly acidotic conditions in Korean beef cattle. New Zealand beef cattle fed on pasture which they harvest by grazing showed significantly lower plasma glucose, cholesterol, lactate and IRI concentrations and enzyme activities than those in Korean and Japanese beef cattle fed on larger amount of concentrate diets. Plasma metabolite concentrations and energy metabolism-related enzyme activities may be good indicators for evaluating metabolic conditions of beef cattle raised by different feeding systems.
  • T. Sako, S. Urabe, A. Kusaba, N. Kimura, I. Yoshimura, H. Tazaki, S. Imai, K. Ono, T. Arai
    VETERINARY RESEARCH COMMUNICATIONS 31(4) 413-417 2007年5月  
  • Akihiro Mori, Hiroyuki Tazaki, Nobuko Mori, Kieko Tan, Yukino Sakamoto, Masaru Hosoya, Ryuma Nuruki, Toshiro Arai
    APPLIED EQUINE NUTRITION AND TRAINING: EQUINE NUTRITION CONFERENCE (ENUCO) 2007 211-214 2007年  査読有り
  • T Arai, Y Tanaka, S Urabe, A Kusaba, H Tazaki, T Ozawa, N Kimura, KK Jung, K Waragaya, T Yuyama, Y Haseba, S Imai
    RESEARCH IN VETERINARY SCIENCE 81(1) 19-23 2006年8月  
    Plasma metabolite and immunoreactive insulin concentrations and activities of enzymes related to energy metabolism in peripheral leukocytes were measured in growing Holstein calves. A ratio of girth of abdomen divided by girth of thorax (A/T ratio) of calves was significantly elevated after weaning, and the A/T ratio maybe a good indicator to evaluate rumen development. Plasma glucose and free fatty acid concentrations were changed in calves accompanying change in feeding. Activities of lactate dehydrogenase with pyruvate as substrate (LDH-P) and hexokinase (HK) in cytosolic fractions of peripheral leukocytes decreased significantly after weaning the calves reflecting the change of energy source from milk replacer with high percentages of fat and glucose and lactose as absorbable carbohydrate to pelleted feed containing starch as less absorbable carbohydrate and roughage. Some peripheral leukocyte enzymes such as LDH and HK may be good indicators to evaluate changes in energy metabolism of growing calves. (c) 2005 Elsevier Ltd. All rights reserved.
  • Yasuhiro Hasa, Hiroyuki Tazaki, Masao Ohnishi, Yuji Oda
    FOOD BIOTECHNOLOGY 20(3) 263-274 2006年  
    Potato pulp containing starch, cellulose, hemicellulose, and pectin is an agricultural by-product in the starch industry. Potato pulp was hydrolyzed by semiaerobic growth of the fungus Amylomyces rouxii, mixed with water, and filtrated to separate water-soluble materials. The obtained extract had the capability to significantly reduce stickiness in the gel made with wheat flour. Similar effects were observed in the extract of potato pulp hydrolyzed by a commercial pectinase. When covered with the extract, the cooked noodles were easily disentangled by shaking after overnight refrigeration. The effective components obtained from the extract by precipitation included pectin predominantly composed of uronic acid and galactose with a molecular weight of 10(5) to 10(6). The extract from potato pulp is useful as an anti-sticking substance for cooked noodles sold in retail stores.
  • 片山 欣哉, 田崎 弘之
    化学と生物 43(12) 780-781 2005年12月1日  
  • K Yunoki, R Musa, M Kinoshita, H Tazaki, Y Oda, O Masao
    BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 68(12) 2619-2622 2004年12月  
    Higher alcohols with a carbon length ranging from 16 to 30 found in the lipophilic fraction from potato pulp were shown to be present as ferulate and in a free form, but not as wax. Thin-layer chromatography of the neutral lipids in potato pulp indicated a few spots with scavenging activity toward the 1,1-diphenyl-2-picrylhydrazyl (DPPH) stable radical, the major active component being characterized as alkyl ferulate which showed almost the same level of activity as gamma-oryzanol.
  • Hattori, S, Kawaharada, C, Tazaki, H, Fujimori, T, Kimura, K, Ohnishi, M, Nabeta, K
    Bioscience Biotechnology Biochemistry 68(12) 2656-2659 2004年12月  
    Thermally decomposed products of (±)-linalyl β-D-glucoside were analyzed by GC and GC/MS. 2,6-Dimethyl-2,6-octadienes produced by mild pyrolysis of linalyl β-D-glucopyranoside under a vacuum were detected and characterized by MS and NMR spectroscopy. This suggests that 2,6-dimethyl-2,6-octadienes are produced during thermal decomposition of the glucoside via proton transfer from the anomeric position to C-6 in the aglycon moiety. A stable isotope labeling experiment directly indicated the new reaction mechanism.
  • Y Hasa, H Tazaki
    BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 68(10) 2212-2214 2004年10月  
    The biosynthesis of fukinolic acid, which had been isolated from the Japanese fuki vegetable, Petasites japonicus, was investigated by feeding selected C-13-labeled compounds to axenic cultures of P. japonicus. [1,2-C-13(2)] sodium acetate and [1-C-13] L-tyrosine were incorporated into the fukiic acid sub group, while [3-C-13] L-phenylalanine was incorporated into the caffeic acid moiety.
  • H Tazaki, J Kawabata, T Fujita
    BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 67(5) 1185-1187 2003年5月  
    The novel Diels-Alder adduct, dicaffeoyl quinone as its hydrate, was formed from the oxidation of 3,4-dihydroxycinnamic acid (caffeic acid) with NaIO4. The structure of this hydrate was determined by spectroscopic methods.
  • H Tazaki, M Ito, M Miyoshi, J Kawabata, E Fukushi, T Fujita, N Motouri, T Furuki, K Nabeta
    BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 66(2) 255-261 2002年2月  
    The new caffeic acid derivative, subulatin (1), was isolated from in vitro cultured liverworts, Jungermannia subulata, Lophocolea heterophylla, and Scapania parvitexta. The structure of 1 involved two caffeic acids, D-glucose, and 2-carboxy-6-(1,2-dihydroxy-ethyl)-4,5dihydroxy-5,6-dihydro-4H-pyran. The connectivity of those and the absolute stereochemistry of 1 were elucidated on the basis of spectroscopic evidence. The antioxidative activity of 1 was comparable to that of alpha-tocopherol. (2'R)-Phaselic acid (2a) and (-)9,2"-epiphylloyl-L-malic acid (4) were also isolated from J. subulata and L. heterophylla, respectively. A chiral HPLC analysis of the p-bromobenzoyl-malic acids derived from 2a showed that 2a from J. subulata was unusual (+)-trans-caffeoyl-D-malic acid.
  • H Tazaki, D Taguchi, T Hayashida, K Nabeta
    BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 65(12) 2613-2621 2001年12月  
    The formation of ortho-quinone from ortho-diphenol is a key step in its dimerization. An NMR analysis of the oxidation of 3,4-dihydroxycinnamic acid (caffeic acid) by NaIO4 revealed the formation of 3-(3',4'-dioxo-1',5'-cyclohexadienyl) propenoic acid (o-quinone) prior to the formation of furofuran-type lignan 4,8-exo-bis (3,4-dihydroxyphenyl)-3,7-dioxabicyclo[3.3.0]octane-2,6-dione. Both electrolytic and enzymatic oxidation of caffeic acid also generated o-quinone. The yields of o-quinone from caffeic acid were quantified by NMR and HPLC analyses. A stable isotope-labeling study of the formation of lignans directly proved the random radical coupling of semiquinone radicals formed from a set of caffeic acid and o-quinone.
  • Hiroyuki Tazaki
    Nippon Nogeikagaku Kaishi 74(2) 137-143 2000年  

MISC

 45

共同研究・競争的資金等の研究課題

 9

産業財産権

 6