Curriculum Vitaes

Hiroyuki Tazaki

  (田崎 弘之)

Profile Information

Affiliation
Professor, Faculty of Veterinary Science, School of Veterinary Medicine, Nippon Veterinary and Life Science University
Degree
博士(農学)

J-GLOBAL ID
200901011481740045
researchmap Member ID
5000081034

Awards

 1

Papers

 87
  • Hiroshi M Ueno, Touko Sato, Satoshi Higurashi, Hiroyuki Tazaki, Yasuhiro Toba
    Current developments in nutrition, 6(6) nzac093, Jun, 2022  
    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], Sep, 2021  
  • 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], Sep, 2021  
  • Ayaka Domon, Kentaro Katayama, Touko Sato, Yuki Tochigi, Hiroyuki Tazaki, Hiroetsu Suzuki
    PLoS ONE, 16(5 May), May, 2021  
    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  
    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.

Misc.

 45

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 2

Research Projects

 9

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 6