Kazuro Miyahara

Obihiro University of Agriculture and Veterinary Medicine, Obibiro, Hokkaidō, Japan

Are you Kazuro Miyahara?

Claim your profile

Publications (26)29.95 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: To clarify the different characteristics of the dominant follicle (DF), the DF in first ovarian follicular wave (DF-1) after spontaneous ovulation and DF in second follicular wave (DF-2) and after induced ovulation of the first-wave DF by GnRH were examined in non-lactating Holstein cows. Follicular maturation of DF-1 and DF-2 were induced by PGF2α and GnRH treatment on Day 6 and 8 (Day 0 = Day of follicular wave emergence), respectively. Follicular growth and blood flow (BF) in the follicular wall of DF-1 and DF-2 were examined. To analyze sex steroids in follicular fluid (FF) and amount of mRNA in granulosa cells, DF-1 and DF-2 were aspirated on Day 8 or 9 in different estrous cycle. Diameter in DF-1 was larger than DF-2 on Day 8 and 9. From Day 8 to 9, BF area (BFA) and percentage of the follicular wall with BF, which represents the degree of distribution of BF, increased in DF-1 but not in DF-2. BFA per length of follicle circumference with BF, which represents the thickness of BF, was not different between DF-1 and DF-2. Concentrations of 17β-estradiol (E2) in plasma, E2 and androstendione in FF and amounts of LH receptor mRNA were greater in the DF-1 on Day 8. Gene expression for steroidogenesis, prostaglandin synthesis and angiogenesis did not differ between DF-1 and DF-2. These results indicated that DF-1 were more active than DF-2 in growth, BF supply and steroidogenesis. The greater BFA observed in the DF-1 may be derived from as a result of the greater vascularity in the follicular wall.
    Animal reproduction science 03/2014; 145(3). DOI:10.1016/j.anireprosci.2014.01.003 · 1.51 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A 9-month-old steer was autopsied due to recurrent ruminal tympany. A macroscopic examination found an enlarged caudal mediastinal lymph node, and a section of the lymph node revealed necrosis with marked calcification, similar to tuberculous lymphadenitis. Histopathologically, the lesion consisted of multiple coagulative necrotic foci and fibrosis with macrophage, lymphocyte, eosinophil and multinucleated giant cell infiltration. Non-uniform width hyphae were detected in the necrotic area and within the cytoplasm of the multinucleated giant cells, and they were found to be anti-Rhizopus arrhizus antibody positive in an immunohistochemical examination. Therefore, the steer was diagnosed with necrotic caudal mediastinal lymphadenitis due to zygomycetes infection, and inhibition of eructation by the enlarged lymph node was the likely cause of the ruminal tympany.
    Journal of Veterinary Medical Science 09/2013; 76(1). DOI:10.1292/jvms.13-0084 · 0.78 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To obtain B-mode ultrasound images of mammary glands in dairy heifers at different stages of growth, 25 clinically normal Holstein heifers were used. The heifers were divided into 5 groups (n=5/group) by stage of their growth: 2-month-old (group 1), 5-month-old (group 2), postpuberty (group 3), mid (group 4), and late (group 5) pregnancy. Furthermore, the sections of mammary glands were observed grossly at postmortem examination in one heifer in each group. Ultrasound images varied with the development of mammary glands. In group 1, the mammary glands had distinctive ultrasonographic findings: an oval to fusiform homogeneous hypoechoic structure. In all groups except group 1, mammary tissue consists of two major areas: a homogeneous, medium echogenic area and a poorly-defined, heterogeneous, hypoechoic area mostly in the superficial part. The superficial hypoechoic area spread more extensively and more irregularly with the development of mammary glands. Most pregnant heifers had irregular and extremely hypoechoic or anechoic areas like lactiferous sinus in the glands. The gross findings of mammary glands suggested that the hypoechoic areas of various shapes represented the lactiferous sinus and ducts. Thus, these results indicate that B-mode ultrasound imaging can visualize the internal structures of udders and could be a useful tool for evaluation of mammary glands in heifers.
    Journal of Veterinary Medical Science 01/2011; 73(1):19-24. DOI:10.1292/jvms.09-0503 · 0.78 Impact Factor
  • Biology of Reproduction 10/2010; · 3.32 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The assisted reproductive techniques (ARTs) such as in vitro fertilization, embryo transfer, and cryopreservation of gametes have contributed considerably to the development of biomedical sciences in addition to improving infertility treatments in humans as well as the breeding of domestic animals. However, ARTs used in canine species have strictly limited utility when compared with other mammalian species, including humans. Although successful somatic cell cloning has been reported, artificial insemination by frozen semen to date is only available for the improved breeding and reproduction for companion and working dogs as well as guide dogs for the blind. We describe here the successful cryopreservation of embryos and subsequent embryo transfer in dogs. Canine embryos were collected from excised reproductive organs after artificial insemination and subsequently cryopreserved by a vitrification method. When the 4-cell to morula stage of cryopreserved embryos were nonsurgically transferred into the uteri of nine recipient bitches using a cystoscope, five recipients became pregnant and four of them delivered a total of seven pups. The cryopreservation of embryos in canine species will facilitate the transportation and storage of genetic materials and will aid in the elimination of vertically transmitted diseases in dogs. In addition, this technique will contribute to the improved breeding of companion and working dogs such as guide dogs, drug-detecting dogs, and quarantine dogs.
    Biology of Reproduction 10/2010; 84(2):363-8. DOI:10.1095/biolreprod.110.087312 · 3.32 Impact Factor
  • Veterinary Radiology &amp Ultrasound 05/2009; 50(3):301-3. DOI:10.1111/j.1740-8261.2009.01538.x · 1.45 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: DNA from 111 ticks collected by flagging in Tokachi district, Eastern Hokkaido, Japan were examined for infection with Rickettsia and Ehrlichia, by PCR and sequencing methodology. For Rickettsia, analysis of the partial sequence of the citrate synthase gene was successfully performed on 11 DNA samples from I. persulcatus, and 7 of them showed 99.8% identical with Rickettsia helvetica while the other 4 showed 99.8% identical with ;Candidatus Rickettsia tarasevichiae'. For Ehrlichia, a partial sequence of the 16S rRNA gene detected from I. persulcatus was 100% identical with that from Ehrlichia muris, and another DNA sample from I. ovatus showed 99.8% identical with Ehrlichia species detected from I. ovatus. The results suggest that the pathogens detected here might be distributed in this area.
    Journal of Veterinary Medical Science 07/2007; 69(6):661-4. DOI:10.1292/jvms.69.661 · 0.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Tick DNA samples from cattle in Xinjiang Uygur Autonomous Region Area, China, were examined for Rickettsia infection by citrate synthase gene-based PCR and sequencing. Four positive samples were detected from Haemaphysalis danieli and high levels of similarity were found with recently detected 'Candidatus Rickettsia principis.'
    Veterinary Parasitology 04/2007; 144(1-2):184-7. DOI:10.1016/j.vetpar.2006.09.019 · 2.46 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To quantify the radiographic parameters of the caudal vena cava (CVC) in healthy cattle and demonstrate their clinical usefulness, the present study compared the ratios of the diameter of the thoracic CVC to the diameter of the aorta (Ao) and length of the thoracic vertebrae (VL), which are all positioned in the same intercostal space, in 81 healthy control cattle (43 growing, 38 adult) and 10 cattle with heart disease. The average diameter of the CVC (CVCave) was correlated with the size of the Ao and VL in the control cows. Although the diameter and pulsation index of the CVC differed significantly between the growing and adult cows, the ratios of CVC/Ao and CVC/VL were fixed values for both the growing and mature cattle. However, in the cattle with heart disease, the pulsation index of the CVC was significantly lower or there was absence of pulsation due to a dilated CVC, and the ratio of CVCave/Ao and CVCave/VL were significantly higher than those in the healthy cattle.
    Journal of Veterinary Medical Science 10/2006; 68(9):995-8. DOI:10.1292/jvms.68.995 · 0.78 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The cryopreservation of ovarian tissues is a technology with significant potential for the preservation of the genetic resource materials of working dogs, including guide dogs for the blind. However, no attempt has been reported on cryopreservation of the canine ovary. Thus, we evaluated a vitrification method for cryopreservation of canine ovaries and determined the potential functionality of vitrified-warmed canine ovaries by means of transplantation into non-obese diabetic-severe combined immunodeficiency (NOD-SCID) mice. All ovarian tissues cryopreserved by vitrification were morphologically normal in terms of histology. Cryopreserved ovaries were transplanted into the ovarian bursa of the NOD-SCID mice, and the xenografts were recovered from 23 of 23 mice (100%) 4 weeks after the operation. The transplanted canine tissue was tightly adhered to the mouse ovary. Although antral follicle formation did not occur after grafting, proliferating cell nuclear antigen immunoreactivity was detectable in many of the granulosa cells in the primary follicles of the grafts. These results indicate that cryopreservation of the canine ovary by vitrification appears to have the potential to restore endocrine function and ovulation potential.
    Journal of Reproduction and Development 05/2006; 52(2):293-9. DOI:10.1262/jrd.17080 · 1.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A high prevalence of larval Echinococcus multilocularis (Em) infection was found in zoo primates in Hokkaido, Japan. In October 1997, a Japanese monkey (Macaca fuscata) died and histopathologically diagnosed as alveolar hydatidosis. Serum samples were collected from the remaining Japanese monkeys and examined for antibodies against Em by enzyme-linked immunosorbent assay and western blotting. Serological tests showed 12 more animals of the remaining 57 monkeys were possibly infected. Ultrasonography revealed that nine of these 12 animals had a cystic lesion in the liver. The band patterns of western blotting in the monkeys were very similar to those in human.
    Journal of Veterinary Medical Science 02/2005; 67(1):133-5. DOI:10.1292/jvms.67.133 · 0.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Chondroitinase ABC (C-ABC) is expected to be a novel agent for chemonucleolysis. The effect of C-ABC was investigated by magnetic resonance (MR) and radiograph. C-ABC was administered into the lumbar intervertebral disks on the clinically normal beagles (n=5), in a dose of 50 microl (12.5 units as C-ABC). MR scans were performed pre-dose, and 1, 3, 7, 14 and 28 days after administration of C-ABC, and the signal intensity (SI) of the nucleus pulposus was measured. Radiographs were taken pre-dose, and 1, 2, 3, 4, 5, 6, 7, 14 and 28 days post-dose, to evaluate narrowing of the disk space in terms of height index (HI). In addition, the quantity of the chondroitin sulfate (CS) and the hyaluronic acid (HA) in the nucleus pulposus were measured by high performance liquid chromatography on day 28 after dosing. SI and HI continuously decreased, following the injection to 37.1% and 78.9% of the pre-dose values, respectively. Statistically significant differences (p<0.01) were observed between the C-ABC group and the control group in the respects on day 1 post-dose. CS and HA contents of the nucleus pulposus were noted to be significantly decreased on day 28 (p<0.01) in the treated group. This agent proved to degenerate proteoglycans in the nucleus pulposus, thus progressively reducing the interdiskal pressure from day 1 post-dose onwards. It is concluded that C-ABC is expected to afford its efficacy from early in the course of chemonucleolysis.
    Journal of Veterinary Medical Science 05/2001; 63(5):521-5. DOI:10.1292/jvms.63.521 · 0.78 Impact Factor
  • Masanori Sasaki · Toyomi Takahashi · Kazuro Miyahara · Hirose aT
    [Show abstract] [Hide abstract]
    ABSTRACT: In vivo intradiscal measurements of pressure in lumbar discs treated with chondroitinase ABC were performed. To determine the decrease in lumbar intradiscal pressure after chemonucleolysis by chondroitinase ABC in sheep. No previous study has assessed in vivo intradiscal pressure after chemonucleolysis. This study investigated the effect of chondroitinase ABC on intradiscal pressure in terms of a dose and time relation. It also included roentgenographic observations and evaluation of the correlation between disc space narrowing and decrease in intradiscal pressure. Chondroitinase ABC was injected in the lumbar intervertebral discs of sheep at doses of 1, 5, and 50 U. Phosphate buffered saline also was injected as a negative control measure. One week before injection, then 1 and 4 weeks afterward, intradiscal pressure was measured using a catheter microtip pressure transducer. Simultaneously, standard lateral roentgenographs were taken, and the disc height index was calculated. The intradiscal pressure clearly was decreased 1 week after chondroitinase ABC injection. A further decrease was observed up to 4 weeks. This pressure decrease was dose dependent. The disc height indexes also decreased with time, but the state of the change was different from that of the changes in intradiscal pressure. No clear quantitative correlation was found between intradiscal pressure and disc height index. Chondroitinase ABC can induce the reduction of intradiscal pressure in the lumbar spine.
    Spine 04/2001; 26(5):463-8. DOI:10.1097/00007632-200103010-00008 · 2.30 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The usefulness of magnetic resonance (MR) is already established, but it has a disadvantage of requiring a long scanning time. A short-time examination is more or less needed so as to be more practical in veterinary clinics. A protocol of the short-time MR examination was devised based on parameters determined, and validity of the protocol was assessed through the diagnosis of clinical cases with intervertebral disc diseases. With this protocol, it was possible to complete an MR examination for the spine within 15 min. The MR images and myelographic findings were correlated well in this study, suggesting the short-time protocol of MR examination can be used in the clinical diagnosis of spinal diseases.
    Journal of Veterinary Medical Science 02/2001; 63(1):51-4. DOI:10.1292/jvms.63.51 · 0.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A 6-year-old female mongrel dog weighing 9.0 kg was presented ananastatic, with clouding of consciousness, bilateral loss of hearing and depressed reactivity of the eyes to light. Magnetic resonance imaging (MRI) examination showed that the calvaria was markedly thickened with compression to the cerebrum and cerebellum. The case of a dog with thickened calvaria with compression of the cerebrum and cerebellum which could not be diagnosed by conventional measures was amenable to diagnosis by MRI. With increased application of MRI examination, such canine cases might increase in number.
    Journal of Veterinary Medical Science 10/1999; 61(9):1055-7. DOI:10.1292/jvms.61.1055 · 0.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The image processing procedure has become widely applied as a visual aid in imaging diagnosis. The subtraction image of MRI obtained by digitally subtracting an unenhanced image from a contrast-enhanced image, depicted a discrete distribution of the contrast agent. Subtraction images in the clinical cases were compared. The subtraction image in a case of chondroma demonstrated a relatively uniform distribution of a contrast agent, with a well delineated neoplastic lesion. The subtraction image in a case of squamous cell carcinoma, the contrast agent was distributed heterogeneously in the carcinoma and well permeated into the muscle. Different patterns of subtraction image were obtained in the clinical cases of chondroma and squamous cell carcinoma in this study. The findings suggest the potential usefulness of the subtraction image for diagnosing the degree of malignancy.
    Journal of Veterinary Medical Science 11/1998; 60(10):1149-51. DOI:10.1292/jvms.60.1149 · 0.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The clinical application of MRI of a cat case of traffic accident was examined. On admission, the animal was unconscious and remained so for 2 days. Radiographs disclosed a fracture in the parietal bone. From the temporary unconscious status and the fracture, cerebral damage was suspected and an MRI examination was performed. The contrecoup injury in the cat case of traffic accident which could not be diagnosed by radiography was diagnosed by MRI examination.
    Journal of Veterinary Medical Science 06/1998; 60(5):647-9. DOI:10.1292/jvms.60.647 · 0.78 Impact Factor
  • Motoji Morozumi · Kazuro Miyahara · Motoyoshi Sato · Tsuneo Hirose
    [Show abstract] [Hide abstract]
    ABSTRACT: Two dogs and a cat with intracranial lesions were evaluated by both computed tomography (CT) and magnetic resonance (MR) imaging. In a dog with vestibular syndrome, better quality images of the medulla oblongata surrounded by thick bones were obtained by MR than by CT, on which the appearance of artifacts impeded the clear image of the area. In a dog with multiple brain metastases of lymphoma, contrast CT delineated lesions more clearly than MR, which was performed one week after CT. During that week dexamethasone which might affect the clarity of MR images of the lesion was administered to reduce brain edema. In a cat with meningeal syndrome of lymphocytic leukemia, only contrast MR imaging identified the width and site of the lesion. These results indicate that it is necessary to select either one of these imaging methods according to the type and site of lesions that are suspected in a particular case.
    Journal of Veterinary Medical Science 10/1997; 59(9):807-10. DOI:10.1292/jvms.59.807 · 0.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study was designed to demonstrate the broad utility of contrast-enhanced magnetic resonance imaging (MRI) for diagnosis of carcinoma. Twenty-six New Zealand White rabbits of either sex (1.7-3.4 kg) were used for the investigation. VX2 carcinoma (squamous cell carcinoma) was implanted in either the brain, lung, ovary, bone or muscle of rabbits. Contrast agent, Gadodiamide Injection, was administered intravenously at a dose of 0.1 mmol/kg. MR images were obtained by a 1.5 T, or a 2.0 T magnetic field strength super-conductive MRI unit. The intensity of the signal for the carcinoma was increased after administration of contrast agent, and the detectability or diagnostic information of post-contrast images was superior to that of pre-contrast images in all models. In addition, no significant side effects were observed during the MRI examination. After diagnosis using MRI, morphological damage in each model was assessed by gross and histopathological examinations. In contrast-enhanced MRI, though there were variations between the models employed, contrast effects in brain and muscle carcinoma models were generally related to differences in capillary permeability, while imaging in lung, ovary and bone carcinoma models was dependent on differences in blood flow rate and the size of interstitial spaces. Overall, our results demonstrate that contrast-enhanced MRI is a useful and safe method for diagnosing tumors.
    Journal of Veterinary Medical Science 06/1996; 58(5):389-96. DOI:10.1292/jvms.58.389 · 0.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The present study was designed to confirm the usefulness of contrast-enhanced magnetic resonance imaging (MRI) in diagnosing strokes of stroke-prone spontaneously hypertensive rats (SHRSP) and middle cerebral artery (MCA) occlusion, hepatocellular carcinoma and hydronephrosis of each experimental rat model. Male Sprague-Dawley rats (250-500 g), male SHRSP (ca. 250 g) and male F344 rats (ca. 300 g) were used for the investigation. Gadodiamide injection (Omniscan, Daiichi Pharmaceutical Co., Ltd. and Nycomed AS, Norway) was administered intravenously as the contrast agent at a dose of 0.1 mmol/kg except in hydronephrosis, where a dose of 0.05 mmol/kg was used. Magnetic resonance (MR) images were obtained with a 1.5T or a 2.0T magnetic field strength MRI unit. The signal intensity of the stroke lesions was increased after administration of gadodiamide injection in SHRSP and MCA-occluded rats. Hepatocellular carcinoma was undetectable without the use of the contrast agent, but the signal intensity of the tumor increased after administration of the gadodiamide injection, allowing the lesions to be detected. The signal intensity of the renal medulla increased in the non-ligated kidney, but not in the hydronephrotic kidney. The information given by the post-contrast images were superior to those obtained from the pre-contrast images in all the models. Contrast effects in SHRSP and MCA-occluded rats were related to differences in capillary permeability, those in rats with hepatocellular carcinoma depended on differences in vascularity, and those in hydronephrotic rats depended on blood flow and permeability.
    Journal of Veterinary Medical Science 05/1996; 58(4):291-5. DOI:10.1292/jvms.58.291 · 0.78 Impact Factor

Publication Stats

193 Citations
29.95 Total Impact Points


  • 1995–2014
    • Obihiro University of Agriculture and Veterinary Medicine
      • • Department of Clinical Veterinary Science
      • • Animal Medical Center
      • • School of Veterinary Medicine
      Obibiro, Hokkaidō, Japan
  • 2011
    • Gifu University
      Gihu, Gifu, Japan