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Dive into the research topics where Hiroko Aida is active.

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Featured researches published by Hiroko Aida.


Systems and Computers in Japan | 2001

A horse identification system using biometrics

Masahiko Suzaki; Osamu Yamakita; Shin-ichi Horikawa; Yuji Kuno; Hiroko Aida; Naoki Sasaki; Ryo Kusunose

This paper introduces an application of iris recognition technology, using the iris pattern for horse identification. There are several problems to be solved in horse iris recognition: (1) It is very difficult for horses to remain motionless, which leads to mislocation and loss of focus during image acquisition, so that the images often have poor quality. (2) Pupil size varies significantly between the conditions of dilation (mydriasis) and contraction (miosis). (3) Horse iris patterns are not clear. As a solution for issue (1), we used the reflection of the illumination sources employed for image acquisition and chose adequate images suitable for recognition. For issues (2) and (3), we propose region extraction appropriate to the equine eye structure, a stable coordinate model for pupil variation, and recognition using orthogonal wrinkles in the iris pattern. Recognition experiments based on 100 sets of horse iris data show that highly accurate horse identification is possible.


Equine Veterinary Journal | 2013

Muscle satellite cells are activated after exercise to exhaustion in Thoroughbred horses.

Minako Kawai; Hiroko Aida; Atsushi Hiraga; Hirofumi Miyata

REASONS FOR PERFORMING STUDY Although satellite cells are well known as muscle stem cells capable of adding myonuclei during muscle repair and hypertrophy, the response of satellite cells in horse muscles to a run to exhaustion is still unknown. OBJECTIVES To investigate the time course of satellite cell activation in Thoroughbred horse muscle after running to exhaustion. We hypothesised that this type of intense exercise would induce satellite cell activation in skeletal muscle similar to a resistance exercise. METHODS Nine de-trained Thoroughbred horses (6 geldings and 3 mares) aged 3-6 years were studied. Biopsy samples were taken from the gluteus medius muscle of the horses before and 1 min, 3 h, 1 day, 3 days, 1 week and 2 weeks after a treadmill run to exhaustion. The numbers of satellite cells for each fibre type were determined by using immunofluorescence staining. Total RNA was extracted from these samples, and the expressions of interleukin (IL)-6, paired box transcriptional factor (Pax) 7, myogenic differentiation 1 (MyoD), myogenin, proliferating cell nuclear antigen (PCNA), insulin-like growth factor (IGF)-I and hepatocyte growth factor (HGF) mRNA were analysed using real-time reverse transcription-PCR. RESULTS The numbers of satellite cells were significantly increased in type I and IIa fibres at 1 week and in type IIa/x fibre at 2 weeks post exercise. The expression of IL-6 mRNA increased significantly by 3 h post exercise. The expression of PCNA mRNA also increased by 1 day after running, indicating that running can initiate satellite cell proliferation. The expression of Pax7, MyoD, myogenin, IGF-I and HGF mRNA peaked at 1 week post exercise. CONCLUSION Satellite cell activation and proliferation could be enhanced after a run to exhaustion without detectable injury as assessed by the histochemical analysis. Understanding the response of satellite cell activation to running exercise provides fundamental information about the skeletal muscle adaptation in Thoroughbred horses.


American Journal of Veterinary Research | 2013

Effect of acute exercise on monocarboxylate transporters 1 and 4 in untrained and trained Thoroughbreds

Yu Kitaoka; Yukari Endo; Kazutaka Mukai; Hiroko Aida; Atsushi Hiraga; Tohru Takemasa; Hideo Hatta

OBJECTIVE To evaluate the effects of a single incremental exercise test (IET) on mRNA expression and protein content of monocarboxylate transporter (MCT) 1 and MCT4 in the gluteus medius muscle of Thoroughbreds. ANIMALS 12 Thoroughbreds (6 males and 6 females; age, 3 to 4 years). PROCEDURES Horses underwent an IET before and after 18 weeks of high-intensity exercise training (HIT). Horses were exercised at 90% of maximal oxygen consumption for 3 minutes during the initial 10 weeks of HIT and 110% of maximal oxygen consumption for 3 minutes during the last 8 weeks of HIT. Gluteus medius muscle biopsy specimens were obtained from horses before (baseline), immediately after, and at 3, 6, and 24 hours after the IET. RESULTS Expression of MCT1 and MCT4 mRNA was upregulated at 3 and 6 hours after the IET in muscle specimens obtained from horses prior to HIT (untrained horses) and at 6 hours after the IET in muscle specimens obtained from horses after HIT (trained horses). For both untrained and trained horses, MCT1 and MCT4 protein contents were increased at 6 hours after the IET and did not differ at 24 hours after the IET, compared with those at baseline. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that a single IET resulted in transient increases in MCT1 and MCT4 mRNA expression and protein content in untrained and trained horses. These results may be important for the elucidation of exercise-induced alterations in lactate metabolism.


Journal of Equine Science | 2013

Effect of Treadmill Exercise and Hydrogen-rich Water Intake on Serum Oxidative and Anti-oxidative Metabolites in Serum of Thoroughbred Horses

Hirokazu Tsubone; Masakazu Hanafusa; Maiko Endo; Noboru Manabe; Atsushi Hiraga; Hajime Ohmura; Hiroko Aida

The present study aimed to clarify changes of oxidative stress and antioxidative functions in treadmill-exercised Thoroughbred horses (n=5, 3 to 7 years old), using recently developed techniques for measurement of serum d-ROMs for oxidative stress, and BAP for antioxidative markers. Also, the effect of nasogastric administration of hydrogen-rich water (HW) or placebo water preceding the treadmill exercise on these parameters was examined. Each horse was subjected to a maximum level of treadmill exercise in which the horses were exhausted at an average speed of 13.2 ± 0.84 m/sec. Blood samples were taken 4 times, immediately before the intake of HW or placebo water at 30 min preceding the treadmill exercise, immediately before the exercise (pre-exercise), immediately after the exercise (post-exercise) and at 30 min following the exercise. In all horses, both d-ROMs and BAP values significantly increased at post-exercise. The increase in d-ROMs tended to be lower in the HW trial, as compared to the placebo trial at pre-exercise. The increase in BAP was considerable at approximately 150% of the pre-exercise values in both the HW and placebo treatment trials. The BAP/d-ROMs ratio was significantly elevated at post-exercise in both treatment trials, while a significant elevation was also observed at pre-exercise in the HW trial. BAP, d-ROM, and the BAP/d-ROM ratio tended to decline at 30 min after the exercise, except BAP and BAP/d-ROMs in the placebo trial. These results demonstrate that the marked elevation of oxidative stress and anitioxidative functions occurred simultaneously in the intensively exercised horses, and suggest a possibility that HW has some antioxidative efficacy.


American Journal of Veterinary Research | 2012

Effects of high-intensity training on lipid metabolism in Thoroughbreds

Yu Kitaoka; Kazutaka Mukai; Hiroko Aida; Atsushi Hiraga; Hiroyuki Masuda; Tohru Takemasa; Hideo Hatta

OBJECTIVE To investigate the effects of high-intensity training (HIT) on carbohydrate and fat metabolism in Thoroughbreds. ANIMALS 12 Thoroughbreds (3 to 4 years old; 6 males and 6 females). PROCEDURES Horses performed HIT for 18 weeks. They ran at 90% or 110% of maximal oxygen consumption ((V)O(2max)) for 3 minutes (5 d/wk) and were subjected to incremental exercise testing (IET) before and after training. Blood samples were collected during IET, and muscle samples were obtained from the gluteus medius muscle immediately after IET. Phosphofructokinase, citrate synthase, and β-3-hydroxyacyl CoA dehydrogenase (β-HAD) activities were measured to determine glycolytic and oxidative capacities. Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and fatty acid translocase (FAT/CD36) protein contents were detected via western blotting. Metabolome analysis was performed via capillary electrophoresis-electrospray ionization mass spectrometry to measure substrate concentrations related to carbohydrate metabolism. RESULTS Peak speed during IET and (V)O(2max) increased after HIT. Activities of citrate synthase and β-HAD increased after HIT, whereas phosphofructokinase activity remained unchanged. The PGC-1α and FAT/CD36 protein contents increased after HIT, but plasma lactate concentration and the respiratory exchange ratio decreased after HIT. The plasma free fatty acid concentration increased after HIT, whereas the glucose concentration was not altered. Fructose 1,6-diphosphate, phosphoenolpyruvate, and pyruvate concentrations decreased after HIT. CONCLUSIONS AND CLINICAL RELEVANCE HIT caused an increase in oxidative capacity in equine muscle, which suggested that there was a decreased reliance on carbohydrate utilization and a concomitant shift toward fatty acid utilization during intensive exercise.


Veterinary Record | 2003

Influence of quinidine and flecainide on autonomic nervous activity in thoroughbred horses

Hajime Ohmura; Atsushi Hiraga; Hiroko Aida; Masayoshi Kuwahara; Hirokazu Tsubone

tion with Sarcoptes scabiei. Journal of WVildlife Diseases 34, 600-61 1 LLOYD, H. G. (1980) The Red Fox. London, Batsford MCALLISTER, E. (1993) Sarcoptic mange. Veterinary Record 132, 120 MCFADYEAN, J. ( 1898) Sarcoptic mange in red foxes. Jouirnal of Comparative Pathology and Therapeutics 11, 92-93 MAFF (1987) Manual of Veterinary Parasitological Laboratory Techniques. Reference book 418. London, Her Majestys Stationery Office MARTINEAU, G. P., VAN NESTE, D. & CHARETTE, R. (1987) Pathophysiology of sarcoptic mange in swine. Part I. Compendium on Continuing Education for the Practicing Veterinarian 9, 51-58 MORNER, T. (1981) The epizootic outbreak of sarcoptic mange in Swedish red foxes (Vulpes vulpes). In Wildlife Diseases of the Pacific Basin and Other Countries. Ed M. E. Fowler. Proceedings of the 4th International Conference of Wildlife Disease Association. Sydney, Australia. pp 124-130 MORNER, T. (1992) Sarcoptic mange in Swedish wildlife. Revue Scientifiquie et Technique Office International Des Epizooties 11, 1 115-1121 MORNER, T. & CHRISTENSSON, D. (1984) Experimental infection of red foxes ( Vulpes vulpes) with sarcoptic mange. Veterinary Parasitology 15, 159164 OLIVE, J. R. & RILEY, C. V. (1948) Sarcoptic mange in the red fox in Ohio. Journal ofMammalogy 29, 73-74 PATERSON, S., PIKE, R. & BOYDELL, P. (1995) Norwegian scabies in a dog. Veterinary Record 136, 393-394 ROLLS, E. C. (1969) They All Ran Wild. Sydney, Angus and Robertson SHUSTROVA, M. V. (1987) Sarcoptic and otodectic mange in red foxes. Veterinariya Moscow 6, 40 STORM, G. L., ANDREWS, R. D., PHILLIPS, R. A., BISHOP, B. D., SINIFF, D. B. & TESTER, J. R. (1976) Morphology, reproduction, dispersal and mortality of midwestern red fox populations. WVildlife Monographs 49, 1-74 TRAINER, D. 0. & HALE, J. B. (1969) Sarcoptic mange in red foxes and coyotes of Wisconsin. Btulletin of the Wildlife Disease Association 5, 387-391 VALTONEN, M. (1978) Skabb hos vildrav och mardhund. 13th Nordic Veterinary Congress. Abo, Finland. pp 246-249


Journal of Equine Science | 2014

The Effects of Inclination (Up and Down) of the Treadmill on the Electromyogram Activities of the Forelimb and Hind limb Muscles at a Walk and a Trot in Thoroughbred Horses

Toshiyuki Takahashi; Akira Matsui; Kazutaka Mukai; Hajime Ohmura; Atsushi Hiraga; Hiroko Aida

ABSTRACT It is important to know the effects of the inclination of a slope on the activity of each muscle, because training by running on a sloped track is commonly used for Thoroughbred racehorses. The effects of incline (from −6 to +6%) on the forelimbs and hind limbs during walking and trotting on a treadmill were evaluated by an integrated electromyogram (iEMG). The muscle activities in the forelimbs (5 horses) and hind limbs (4 horses) were measured separately. Two stainless steel wires were inserted into each of the brachiocephalicus (Bc), biceps brachii (BB), splenius (Sp), and pectoralis descendens (PD) in the forelimb experiment and into the longissimus dorsi (LD), vastus lateralis (VL), gluteus medius (GM), and biceps femoris (BF) in the hind limb experiment. The EMG recordings were taken at a sampling rate of 1,000 Hz. At a walk, the iEMG values for the forelimb were not significantly different under any of the inclinations. In the hind limb, the iEMG values for the GM and BF significantly decreased as the inclination decreased. At a trot, the iEMG values for the Bc in the forelimb significantly decreased as the inclination of the treadmill decreased. In the hind limb, the iEMG values for the LD, GM, and BF significantly decreased as the inclination decreased. Uphill exercise increased the iEMG values for the Bc, LD, GM, and BF, while downhill exercise resulted in little increase in the iEMG values. It was concluded that the effects of inclination on the muscle activities were larger for the uphill exercises, and for the hind limb muscles compared with the forelimb muscles.


Journal of Equine Science | 2016

Profiling of exercise-induced transcripts in the peripheral blood cells of Thoroughbred horses

Teruaki Tozaki; Mio Kikuchi; Hironaga Kakoi; Kei-ichi Hirota; Kazutaka Mukai; Hiroko Aida; Seiji Nakamura; Shun-ichi Nagata

ABSTRACT Transcriptome analyses based on DNA microarray technology have been used to investigate gene expression profiles in horses. In this study, we aimed to identify exercise-induced changes in the expression profiles of genes in the peripheral blood of Thoroughbred horses using DNA microarray technology (15,429 genes on 43,603 probes). Blood samples from the jugular vein were collected from six horses before and 1 min, 4 hr, and 24 hr after all-out running on a treadmill. After the normalization of microarray data, a total of 26,830 probes were clustered into four groups and 11 subgroups showing similar expression changes based on k-mean clustering. The expression level of inflammation-related genes, including interleukin-1 receptor type II (IL-1R2), matrix metallopeptidase 8 (MMP8), protein S100-A8 (S100-A8), and serum amyloid A (SAA), increased at 4 hr after exercise, whereas that of c-Fos (FOS) increased at 1 min after exercise. These results indicated that the inflammatory response increased in the peripheral blood cells after exercise. Our study also revealed the presence of genes that may not be affected by all-out exercise. In conclusion, transcriptome analysis of peripheral blood cells could be used to monitor physiological changes induced by various external stress factors, including exercise, in Thoroughbred racehorses.


Journal of Equine Science | 2014

In Vivo Measurements of Flexor Tendon and Suspensory Ligament Forces During Trotting Using the Thoroughbred Forelimb Model

Toshiyuki Takahashi; Kazutaka Mukai; Hajime Ohmura; Hiroko Aida; Atsushi Hiraga

ABSTRACT The purpose of this study was to create a lower forelimb model of the Thoroughbred horse for measuring the force in the superficial and deep digital flexor tendons (SDFT and DDFT), and the suspensory ligament (SL) during a trot. The mass, centers of gravity, and inertial moments in the metacarpus, pastern, and hoof segments were measured in 4 Thoroughbred horses. The moment arms of the SDFT, DDFT, and SL in the metacarpophalangeal (fetlock) and distal interphalangeal (coffin) joints were measured in 7 Thoroughbred horses. The relationship between the fetlock joint angle and the force in the SL was assessed in 3 limbs of 2 Thoroughbred horses. The forces in the SDFT, DDFT, and SL during a trot were also measured in 7 Thoroughbred horses. The mass of the 3 segments, and the moment arms of the SDFT and DDFT in the fetlock joint of the Thoroughbred horses were smaller than those of the Warmblood horses, whereas the other values were almost the same in the 2 types. The calculated force in the SDFT with this Thoroughbred model reached a peak (4,615 N) at 39.3% of the stance phase, whereas that in the DDFT reached a peak (5,076 N) at 51.2% of the stance phase. The force in the SL reached a peak (11,957 N) at 49.4% of the stance phase. This lower forelimb model of the Thoroughbred can be applied to studying the effects of different shoe types and change of hoof angle for the flexor tendon and SL forces.


American Journal of Veterinary Research | 2017

Effects of maintaining different exercise intensities during detraining on aerobic capacity in Thoroughbreds

Kazutaka Mukai; Atsushi Hiraga; Toshiyuki Takahashi; Akira Matsui; Hajime Ohmura; Hiroko Aida; James H. Jones

OBJECTIVE To determine whether racehorses undergoing regular exercise at 2 intensities or stall rest during a period of reduced training (detraining) would differentially maintain their cardiopulmonary and oxygen-transport capacities. ANIMALS 27 Thoroughbreds. PROCEDURES Horses trained on a treadmill for 18 weeks underwent a period of detraining for 12 weeks according to 1 of 3 protocols: cantering at 70% of maximal rate of oxygen consumption ([Formula: see text]o2max) for 3 min/d for 5 d/wk (canter group); walking for 1 h/d for 5 d/wk (walk group); or stall rest (stall group). Standardized treadmill exercise protocols (during which cardiopulmonary and oxygen-transport variables were measured) were performed before and after detraining. RESULTS Mass-specific [Formula: see text]o2max, maximal cardiac output, and maximal cardiac stroke volume of all groups decreased after 12 weeks of detraining with no differences among groups. After detraining, arterial-mixed-venous oxygen concentration difference did not decrease in any group, and maximal heart rate decreased in the walk and stall groups. Run time to exhaustion and speeds eliciting [Formula: see text]o2max and maximal heart rate and at which plasma lactate concentration reached 4mM did not change in the canter group but decreased in the walk and stall groups. CONCLUSIONS AND CLINICAL RELEVANCE Horses following the cantering detraining protocol maintained higher values of several performance variables compared with horses following the walking or stall rest protocols. These results suggested that it may be possible to identify a minimal threshold exercise intensity or protocol during detraining that would promote maintenance of important performance-related variables and minimize reductions in oxygen-transport capacity in horses.

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Atsushi Hiraga

Japan Racing Association

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Hajime Ohmura

Japan Racing Association

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Kazutaka Mukai

Japan Racing Association

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Yutaka Mizuno

Japan Racing Association

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Akira Matsui

Japan Racing Association

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Seiji Hobo

Japan Racing Association

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James H. Jones

University of California

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Hirokazu Tsubone

National Institute for Environmental Studies

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