Hideyuki Sakamoto

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Four adult Hokkaido brown bears were used as semen donors, and semen characteristics were examined before freezing and after thawing. A total of 10 electroejaculates were diluted with Tris-egg yolk extender and cooled to 4 degrees C over 90 min. Spermatozoa were equilibrated with 4.7% glycerol for 80 min. Semen packed in 0.25 ml plastic straws were frozen(More)
Tetrameric bovine liver catalase (BLC) is unstable because of its dissociation into subunits at low enzyme concentrations and the conformational change of the subunits at high temperatures. In this work, for stabilization of BLC, the enzyme was covalently conjugated with liposome membranes composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC),(More)
The present study aimed to establish simple systems for measuring fecal steroid hormones in order to monitor the reproductive profiles of captive Hokkaido brown bears. The efficiency of fecal sample processing at the steps of dehydration and extraction and the correlation between steroid concentrations in matched fecal and blood samples were studied. Then,(More)
Amid changing economic situation rapidly, how to sustain local/cultural resources and distribute their value to many customers is crucial in a number of business communities. In tourism industry, although there are a lot of activities for such struggles, a small number of the global comparison studies are a problem for exploring and adopting the more(More)
Hepatocellular carcinoma with metastases to lymph nodes and adrenal glands was found in a 26-year-old male Hokkaido brown bear (Ursus arctos yesoensis). Left hepatic lobe was largely replaced by well-differentiated neoplastic cells, whereas poorly differentiated tumor cells had proliferated in part of the left hepatic lobe, in scattered nodules in the(More)
Hiroki Funato, Dr. Eng. Jia Li, Dr. Eng. Masayoshi Takahashi, Dr. Eng. Isao Hoda Hideyuki Sakamoto Ryuichi Saito OVERVIEW: To ensure vehicle safety and comfort, there is a need to minimize interference due to electromagnetic noise from automotive electronics. While automotive manufacturers have stipulated EMC standards for this purpose that component(More)
The vomeronasal organ (VNO) is a peripheral receptor structure that is involved in reproductive behavior and is part of the vomeronasal system. Male bears exhibit flehmen behavior that is regarded as the uptake of pheromones into the VNO to detect estrus in females. However, the morphological and histological features of the VNO in bears have not been(More)
The longitudinal changes in fecal steroid hormone concentrations and sexual behavior in 2 mated/pregnant and 3 non-mated female Hokkaido brown bears were investigated during the breeding season. Behavioral estrus (standing) lasted for 14 and 32 days in the mated females and for 25 to 36 days in the non-mated females. In non-mated females, sexual behavior,(More)
Humeral chondrosarcoma was found in an 18-year-old male Hokkaido brown bear (Ursus arctos yesoensis). Necropsy revealed a large firm mass under the left superficial pectoral muscle at the axillary region. The mass involved the left shoulder joint and peripheral muscles, and connected to the head of the humerus with osteolysis. Histopathologically, the mass(More)
Artificial insemination (AI) can help to avoid inbreeding and genetic degeneration for sustaining genetically healthy populations of endangered species in captivity. Collection of a sufficient quantity of viable sperm is an essential first step in the AI process. In the present study, we examined the effects of frequent electroejaculation on semen(More)
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