Tatsuya Hori

Nippon Veterinary and Life Science University, Tokyo, Tokyo-to, Japan

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Publications (44)41.89 Total impact

  • Article: Changes in Prostaglandin E2 Levels in Seminal Plasma during Ejaculation and the Effect of Exogenous Prostaglandin E2 on Semen Volume in the Dog.
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    ABSTRACT: In healthy male dogs, peripheral plasma testosterone (T), prostaglandin E2 (PGE2), and seminal plasma PGE2 levels were measured before, during, and after ejaculation and semen quality was examined after oral administration of PGE2. Plasma T and PGE2 levels did not change during these periods, but seminal plasma PGE2 level in the first and second fraction was significantly higher than that at 0-5 and 5-10 min after the start of ejaculation of the third fraction. Semen volume but not quality increased after PGE2 administration. In conclusion, large amounts of PGE2 are released from the prostate gland during the early part of ejaculation and that PGE2 plays an essential role in secretion of seminal plasma.
    Journal of Veterinary Medical Science 04/2013; · 0.85 Impact Factor
  • Article: Therapeutic effect of frequent injections of GnRH analogue in a beagle with knobbed acrosome abnormality of sperm.
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    ABSTRACT: A Beagle dog (3 years old) that ejaculated high percentages (mean ± SE: 29.1 ± 1.2%) of sperm with a knobbed acrosome abnormality and a low number of sperm and that also had a low plasma testosterone (T) level was given 10 subcutaneous injections of 1 µg of gonadotropin-releasing hormone analogue (GnRH-A) at 3-day intervals. The plasma T level and number of sperm increased 12-14 weeks after the first injection. Although the percentages of sperm with knobbed acrosome abnormality did not change after the GnRH-A therapy, the number of sperm and percentage of actively motile sperm increased after the therapy, and a bitch gave birth to 5 healthy puppies after intravaginal artificial insemination with fresh semen collected 14 weeks after the first injection.
    Journal of Veterinary Medical Science 09/2011; 74(2):201-4. · 0.85 Impact Factor
  • Article: Comparison of fertility on intrauterine insemination between cryopreserved ejaculated and cauda epididymal sperm in dogs.
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    ABSTRACT: The fertility was compared between ejaculated and cauda epididymal sperm sensitized with prostatic fluid in dog after freeze-thawing using the fertility of ova from the contralateral ovary after injection (2 × 10(8) sperm) into dog uterus on the unilateral ovariectomized side, on the basis of the presence or absence of conception. No significant difference was observed in sperm quality after freeze-thawing between the two groups and conception rates were equivalent and low. Therefore, to achieve a high fertility by intrauterine insemination of canine frozen-thawed ejaculated and cauda epididymal sperm, intrauterine insemination on both sides is recommended, rather than insemination with a lot of sperm of the uterine horn on one side.
    Journal of Veterinary Medical Science 08/2011; 73(12):1685-8. · 0.85 Impact Factor
  • Article: Surgical intrauterine insemination with cat semen cryopreserved with Orvus ES paste or sodium lauryl sulfate.
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    ABSTRACT: The mean post-thaw sperm motilities of feline frozen semen prepared with 1% OEP or 3 g/ml SLS as a cryoprotective agent, in addition to 7% glycerin, were 35.0 ± 2.4 and 37.0 ± 2.5%, respectively, showing no significant difference. On unilateral intrauterine insemination (UIUI) using these semen samples at a sperm number of 40 × 10(6), the conception rate was 70.0% (7/10) in the OEP group and 30% (3/10) in the SLS group, showing that the rate was higher in the OEP group, but the difference was not significant. It was suggested that sperm in frozen semen showing the above qualities were transferred to the contralateral uterine horn on UIUI.
    Journal of Veterinary Medical Science 02/2011; 73(2):259-62. · 0.85 Impact Factor
  • Article: Distribution of glycoproteins on feline testicular sperm, epididymal sperm and ejaculated sperm.
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    ABSTRACT: Glycoproteins (GPs) are known to be involved in the phenomenon of sperm maturation and capacitation. In the present study, we investigated the attachment of GPs on sperm cell membrane during the process of feline sperm maturation from testicular sperm to ejaculated sperm by using 8 FITC-labeled lectins. The results showed that 3 types of GPs were presented on testicular sperm and 7 on caput epididymal sperm. Corpus and cauda epididymal sperm and ejaculated sperm had GPs detected by 8 FITC-labeled lectins used in the present study. This study demonstrates the part of the characteristic of GPs that are present on the feline sperm cell membrane during the process of sperm maturation.
    Journal of Veterinary Medical Science 01/2011; 73(6):827-9. · 0.85 Impact Factor
  • Article: The qualities of cryopreserved epididymal sperm collected from feline epididymides stored at low temperature.
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    ABSTRACT: We observed the influences of low-temperature storage of the feline epididymis on the epididymal semen qualities before and after cryopreservation to identify the optimal duration for low-temperature storage of the epididymis. After excision, the feline epididymis was stored at 4 degrees C for 0-72 hr and then subjected to epididymal sperm collection. When sperm from the refrigerated cauda epididymis were frozen and thawed, there was no significant difference in sperm motility between the 0- and 24-hr low-temperature storage groups, but sperm motility was significantly decreased in the 48-hr storage group. The above findings suggested that low-temperature storage of the epididymis until 24 hr is useful for frozen sperm collected from the feline cauda epididymis.
    Journal of Veterinary Medical Science 06/2010; 72(6):777-80. · 0.85 Impact Factor
  • Article: Usefulness of addition of Orvus ES paste and sodium lauryl sulfate to frozen feline semen.
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    ABSTRACT: It has been shown that addition of the surfactant Orvus ES paste (OEP) and its main component sodium lauryl sulfate (SLS) to boar or dog semen before freezing improves post-thaw sperm motility and protects acrosome caps. In this study, we investigated the usefulness of the addition of OEP (0, 1, 2 and 4%) or SLS (0, 1, 2, 3 and 4 mg/ml) to cat ejaculates before freezing and their concentrations. Among the OEP addition groups, the 1% OEP group showed higher sperm motility than the other groups. Among the SLS addition groups, the 3 mg/ml SLS group showed slightly higher sperm motility and viability than the other groups. Comparison between the 1% OEP and 3 mg/ml SLS addition groups suggested a higher percentage of sperm with an acrosome cap in the 1% OEP group. The other sperm properties did not significantly differ between the 2 groups. These results indicate that addition of 1% OEP or 3 mg/ml SLS is effective for freezing of cat ejaculated semen.
    Journal of Veterinary Medical Science 11/2009; 72(1):23-7. · 0.85 Impact Factor
  • Article: Changes in plasma testosterone level and semen quality after frequent injections of GnRH analogue in a Beagle dog with azoospermia.
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    ABSTRACT: A Beagle with a low plasma testosterone (T) level and azoospermia was given 10 subcutaneous injections of 1 microg gonadotropin-releasing hormone analogue (GnRH-A) per head at intervals of 3 days (Experiment 1), and 6 months after the final injection was given, 15 subcutaneous injections of 2 microg GnRH-A were given at intervals of 2 days (Experiment 2). The plasma T level increased and peaked at 8 weeks after the first injection of GnRH-A in both Experiment 1 and Experiment 2. Motile sperm were detected in the semen collected 8 weeks and 7 weeks after the first injection in Experiment 1 and Experiment 2, respectively. The total number of sperm peaked 9 weeks after the first injection in both Experiment 1 (4.5 x 10(6)) and Experiment 2 (72.8 x 10(6)).
    Journal of Veterinary Medical Science 10/2009; 71(10):1373-5. · 0.85 Impact Factor
  • Article: Influence of the time between removal and cooling of the canine epididymis on post-thaw caudal epididymal sperm quality.
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    ABSTRACT: The effects of the time period between canine epididymis removal and cooling on post-thaw caudal epididymal sperm quality were investigated. Sperm recovered from the epididymis stored for 6 hr at 4 or 20 degrees C exhibited similar motility. However, when the epididymis was stored for 12 hr or longer at 20 degrees C, sperm motility was significantly lower than that at 4 degrees C (p<0.01). The post-thawed qualities of sperm recovered from the caudal epididymides that had been stored at 20 degrees C for 0 or 6 hr and then at 4 degrees C for 24 hr after removal were not significantly different. Therefore, leaving the canine epididymis at 20 degrees C for up to 6 hr after its removal may have little effect on the post-thaw quality of recovered caudal epididymal sperm.
    Journal of Veterinary Medical Science 07/2009; 71(6):811-5. · 0.85 Impact Factor
  • Article: Testicular superoxide dismutase activity, heat shock protein 70 concentration and blood plasma inhibin-alpha concentration of dogs with a Sertoli cell tumor in a unilateral cryptorchid testis.
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    ABSTRACT: The proportions of Sertoli cell tumor (SCT), seminoma and Leydig cell tumor in 50 dogs with unilateral testicular tumors were 52%, 36% and 12%, respectively. The rate of occurrence of SCT in the cryptorchid testis was very high (71%). The testicular superoxide dismutase (SOD) activity, testicular heat shock protein (HSP) 70 concentration and peripheral blood plasma inhibin (INH)-alpha concentration of 10 dogs with a unilateral cryptorchid testis and no testicular tumors, 10 dogs with SCT in a unilateral cryptorchid testis and 10 normal dogs, all aged 5-15 years, were measured in order to identify high risk factors for the occurrence of SCT in the canine cryptorchid testis. The mean SOD activity in cryptorchid testes and SCTs was significantly lower and higher, respectively, than in normal testes (both P<0.01). The mean HSP 70 concentration in both cryptorchid testes and SCTs was significantly higher than in normal testes (both P<0.01). The mean plasma INH-alpha concentration of the cryptorchid and SCT dogs was significantly lower and higher, respectively, than in normal dogs (P<0.05 and 0.01, respectively). The low SOD activity in the cryptorchid testis, low blood plasma INH-alpha concentration of the cryptorchid dogs and high HSP 70 concentration in the SCTs may be related to the occurrence of SCT and tumor cell proliferation in canine cryptorchid testes.
    Journal of Veterinary Medical Science 12/2007; 69(12):1259-62. · 0.85 Impact Factor
  • Article: Changes in the plasma testosterone level and testicular superoxide dismutase activity of 5 azoospermic beagles after GnRH analogue injections.
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    ABSTRACT: The peripheral blood plasma testosterone (T) levels and superoxide dismutase (SOD) activity were measured in 5 azoospermic (AZ-) beagles. The mean values in the AZ-dogs were significantly lower than in 7 control beagles (P<0.001). Subcutaneous injections of 1 mug/kg GnRH analogue three times weekly in the AZ-dogs induced significant increases in mean T level and SOD activity (P<0.05) and improvement in spermatogenesis. Thus, spermatogenic function in the dog appears to be maintained by T and normal SOD activity in the testis.
    Journal of Veterinary Medical Science 05/2007; 69(5):561-2. · 0.85 Impact Factor
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    Article: Superoxide dismutase and catalase activities in the seminal plasma of normozoospermic and asthenozoospermic Beagles.
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    ABSTRACT: We measured the blood plasma testosterone (T) levels and superoxide dismutase (SOD) and catalase activities in the seminal plasma of the ejaculates of 5 normal (2-5 years old) and 5 asthenozoospermic (AZ-) (3-5 years old) Beagles. Sperm ejaculated by AZ-dogs was incubated for 3 hr in Eagle's MEM only (controls) or Eagle's MEM containing 100 units/ml of SOD or catalase. Sperm motility was examined during incubation. The mean (+/- SE) plasma T level of the AZ-dogs (1.2 +/- 0.2 ng/ml) was significantly lower than in the normal dogs (2.5 +/- 0.2 ng/ml) (P<0.005). The mean (+/- SE) seminal plasma SOD and catalase activities (18.8 +/- 1.9 and 0.5 +/- 0.1 unit/g protein, respectively) were significantly lower in the AZ-dogs than in the normal dog (43.3 +/- 2.5 and 2.2 +/- 0.4 unit/g protein, respectively) (P<0.001 and 0.01, respectively). The motility of sperm incubated in Eagle's MEM containing SOD or catalase was significantly higher than that of control sperm incubated in only Eagle's MEM after 2 or 3 hr of incubation (P<0.05). The results of this study indicate that poor T secretion by the testes and low antioxidant enzyme activities are related to AZ in the dog.
    Journal of Veterinary Medical Science 03/2007; 69(2):133-6. · 0.85 Impact Factor
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    Article: Treatment of prostatic abscesses by aspiration of the purulent matter and injection of tea tree oil into the cavities in dogs.
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    ABSTRACT: Ultrasonography-guided transabdominal needle aspiration was carried out to remove 3 to 14 ml of purulent matter from the cavities of prostatic abscesses in 6 dogs, and the same volume of tea tree oil was injected into the cavities to treat the abscesses. The same treatment was repeated 3 weeks later in 4 dogs, and subsequent disappearance of the purulent matter in the cavities and a marked reduction in the volume of the cavities were observed. These findings indicate that the treatment of prostatic abscesses by aspiration of the purulent matter and injection of tea tree oil into the cavities is very effective in dogs.
    Journal of Veterinary Medical Science 12/2006; 68(11):1215-7. · 0.85 Impact Factor
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    Article: Effects of liquid nitrogen vapor sensitization conditions on the quality of frozen-thawed dog spermatozoa.
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    ABSTRACT: The freezing conditions for preparation of frozen canine semen by the plunging method were investigated with regard to the period of sensitization in liquid nitrogen (LN2) vapor and the height from LN2, and the semen qualities after thawing were compared with those of canine semen prepared by the simple freezer method previously reported by us. In the plunging method, 9 semen straws were prepared under the same conditions, horizontally kept at 5, 7, and 10 cm above the LN2 surface in a styrene foam box for 5, 10, and 15 min, and then plunged into LN2. The semen qualities immediately after thawing were high in the 7 cm/10 min (cooling rate: -4 to -22 degrees C/min) and 10 cm/15 min groups (cooling rate: -6 to -10 degrees C/min). On comparison of frozen semen prepared by the plunging method (7 cm/10 min) with frozen semen prepared by the simple freezer method, sperm motility and viability were significantly higher for the frozen semen prepared by the plunging method. The cooling rate in freezing was higher for the simple freezer method (cooling rate: -6 to -50.9 degrees C/min) than the plunging method. Based on these findings, horizontal placement of canine semen straws above LN2 to reduce the temperature at a slow cooling rate of about -10 degrees C/min, followed by plunging into LN2 after sensitization for 10-15 min, provides good semen qualities after thawing.
    Journal of Veterinary Medical Science 11/2006; 68(10):1055-61. · 0.85 Impact Factor
  • Article: Effects of addition of sodium lauryl sulfate on frozen-thawed canine spermatozoa.
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    ABSTRACT: The addition of Orvus ES paste (OEP) to extender may be essential for preparing frozen dog semen. The major ingredient of OEP is sodium lauryl sulfate (SLS). In this study, we compared the effect of SLS on frozen dog semen with that of OEP. There were no significant differences between the 2-mg/ml SLS group and OEP group concerning sperm motility, viability and the percentage of viable sperm with intact acrosomes after freeze-thawing. These results suggest that the effectiveness of frozen dog semen extender containing 2 mg/ml of SLS is similar effective to that demonstrated for OEP.
    Journal of Veterinary Medical Science 11/2006; 68(10):1125-8. · 0.85 Impact Factor
  • Article: Intrauterine transfer of early canine embryos.
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    ABSTRACT: The success rate of in vitro fertilization (IVF) in dogs is low and only early embryos have been obtained. In the present study, we investigated the use of intrauterine transfer of early-stage canine embryos to obtain pups. Twenty-three female dogs, in which the date of ovulation (based on plasma progesterone concentrations) differed by +/-1 day, were used (10 donors and 13 recipients). The uterine tube was extirpated under general anesthesia 1-4 days after mating (5-7 days after ovulation), and descending perfusion was done to collect embryos. Embryos were examined and transferred into the uterine horn of a recipient, ipsilateral to the ovary with the most corpora lutea. Pregnancy was established in one of eight bitches that received early embryos (zygote to 4-cell embryos); she received two zygotes and one 2-cell embryo and delivered two puppies. Although intrauterine transfer of early embryos (zygote to 4-cell embryos) was difficult, pregnancy was achieved, suggesting that uterine tube transfer is appropriate for these early-stage embryos.
    Theriogenology 11/2006; 66(6-7):1703-5. · 1.96 Impact Factor
  • Article: Estradiol benzoate for preventing pregnancy in mismated dogs.
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    ABSTRACT: We investigated the use of a single treatment of estradiol benzoate (E2B) to prevent pregnancy in mismated dogs, including effects of dose, side effects, and mechanism of action. We used 74 female beagles aged 1-10 year. A single treatment of E2B (0.025, 0.05, 0.10, or 0.20 mg/kg; 10 dogs/dose) given 2 days after mating (5 days after ovulation) resulted in pregnancy rates of 70, 50, 10, and 0%, respectively, whereas pregnancy rate was 100% in 5 untreated (control) dogs. There were no side effects in dogs given E2B, regardless of dose. To clarify the mechanism of prevention of pregnancy, we investigated embryonic descent in the uterine tube and embryonic degeneration after treatment with 0.025 or 0.20 mg/kg of E2B; treatment delayed embryonic descent in the uterine tube and increased the incidence of embryonic degeneration. In conclusion, a single treatment of 0.020 mg/kg of E2B given 2 days after mating effectively and safely prevented pregnancy in dogs.
    Theriogenology 11/2006; 66(6-7):1568-72. · 1.96 Impact Factor
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    Article: A trial of intrauterine insemination using a fiberscope in the giant panda (Ailuropoda melanoleuca).
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    ABSTRACT: An intrauterine insemination technique using a fiberscope was investigated in the giant panda. A septal wall was present about 5 cm from the vulva, the external urethral orifice was present in the ventral region, and the entrance (pseudocervix) to the vagina was present in the dorsal region. The uterovaginal region protruded in the dorsal region about 15 cm from the pseudocervix. The external uterine orifice was present in the uterovaginal region, revealing that intrauterine insemination can be easily performed. This technique may greatly contribute to artificial reproduction of the giant panda.
    Journal of Veterinary Medical Science 10/2006; 68(9):987-90. · 0.85 Impact Factor
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    Article: Effects of hyaluronic acid on Ca(2+) influx, lactate dehydrogenase activity, and cyclic AMP synthesis in canine ejaculated sperm during In Vitro capacitation.
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    ABSTRACT: The effects of hyaluronic acid, which comprises the cumulus intercellular matrix, on Ca(2+) influx, lactate dehydrogenase (LDH) activity, and cyclic AMP synthesis in canine sperm during capacitation was investigated. Ejaculated sperm were collected from 10 Beagle dogs and the sperm were incubated for 4 hr in Eagle's MEM containing 10 microg/ml of hyaluronic acid. The percentages of actively motile sperm, hyperactivated sperm (HA-sperm), acrosome-reacted sperm (AR-sperm), and sperm labeled with fluoresceinated Ca(2+) indicator (Ca(2+)-labeled sperm) were evaluated to assess Ca(2+) influx into the sperm. LDH activity and cAMP concentration were measured in homogenized sperm. The mean percentages of motile sperm, HA-sperm, and Ca(2+)-labeled sperm in the MEM containing hyaluronic acid were higher than in the control medium (P<0.05, 0.05, and 0.01, respectively), but there was no difference between the percentages of AR-sperm. Mean LDH activity and mean cAMP concentration were also significantly higher than the control values (P<0.05). The percentages of HA-sperm correlated with those of Ca(2+)-labeled sperm (r(2)=0.810). The results indicate that hyaluronic acid increases Ca(2+) influx, LDH activity, and cAMP synthesis in canine ejaculated sperm during capacitation in vitro.
    Journal of Veterinary Medical Science 02/2006; 68(2):119-23. · 0.85 Impact Factor
  • Article: Changes in plasma testosterone levels and semen quality after 3 injections of a GnRH analogue in 3 dogs with spermatogenic dysfunction.
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    ABSTRACT: Three male Beagles with low plasma luteinizing hormone and testosterone levels and spermatogenic dysfunction (SD-dogs) were given 3 weekly subcutaneous injections of a gonadotropin-releasing hormone analogue (Buserelin; GnRH-AB). The plasma T level of all of the SD-dogs increased and peaked at 4-6 weeks after the first injection. The total number of sperm and the sperm motility of the three SD-dogs increased 5-7 weeks after the first injection. Therefore, the authors concluded that 3 weekly injections of GnRH-AB transiently improves semen quality in some cases of canine spermatogenic dysfunction.
    Journal of Veterinary Medical Science 01/2006; 67(12):1249-52. · 0.85 Impact Factor