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| Registros recuperados: 12 | |
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| Shirasuna, Koumei; Watanabe, S.; Oki, N.; Wijayagunawardane, M. P. B.; Matsui, Motozumi; Ohtani, M.; Miyamoto, Akio; 白砂, 孔明; 松井, 基純; 宮本, 明夫. |
| Prostaglandin F-2 alpha (PGF(2 alpha)) is the primary luteolysin in the cow, and luteal endothelin-1 (ET-1) interacts with PGF(2 alpha) during the process of luteolysis. In contrast, a developing corpus luteum (CL) is refractory to exogenous administration of PGF(2 alpha). Thus, the present study was aimed to investigate the functional relationship between ET-1 and PGF(2 alpha) in the mid-CL (PGF(2 alpha)-sensitive) and early-CL (PGF(2 alpha)-refractory). In the mid-CL model, cows (n = 6/treatment) were assigned to receive one of five types of treatments on day 10 of the estrous cycle: (1) an injection of saline; control, (2) a 500 jig of PGF2. analogue (sufficient dose to induce luteolytis); full-PG, (3) an intraluteal injection of 0.25 mg ET-1; ET-1, (4)... |
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Palavras-chave: Endothelin-1; Prostaglandin F-2 alpha; Luteolysis; Corpus luteum; Cow. |
| Ano: 2006 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/825 |
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| MIYAMOTO, Akio; SHIRASUNA, Koumei; HAYASHI, Ken-Go; KAMADA, Daichi; KAWASHIMA, Chiho; KANEKO, Etsushi; ACOSTA, Tomas J.; MATSUI, Motozumi; 宮本, 明夫; 白砂, 孔明; 川島, 千帆; 松井, 基純. |
| Ultrasonography (US) has been applied to the ovary and the uterus of domestic animals from the late 1980s, and established in 1990s as a practical tool for animal production. US made it possible to detect pregnancy at a very early stage and, most importantly, to observe the real-time dynamics of follicular development and hence the discovery of follicular waves. This has greatly contributed to our understanding of ovarian physiology and helped us to develop several "pin-point" protocols for hormonal treatment. While US may not seem to fit preconceived ideas of a "green" technology, it does not contravene environmental priorities, and it is non-invasive ("ethical") and non-hormonal ("clean"). Using the US technology that is now commercially available at a... |
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Palavras-chave: Color Doppler ultrasound; Blood flow; Ovary; Reproduction; Cow. |
| Ano: 2006 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2983 |
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| SHIRASUNA, Koumei; ASAHI, Takayuki; SASAKI, Motoki; SHIMIZU, Takashi; MIYAMOTO, Akio; 白砂, 孔明; 佐々木, 基樹; 清水, 隆; 宮本, 明夫. |
| We have shown that luteal blood flow increases in the peripheral vasculature of the mature corpus luteum (CL) prior to the onset of luteolysis in response to prostaglandin F2α (PGF2α) in the cow, but this phenomenon does not occur in the early CL. We therefore hypothesize that this acute increase of luteal blood flow occurs by vasodilation of large blood vessels due to local release of nitric oxide (NO). In the present study, we characterized the CL vasculature together with endothelial NO synthase (eNOS) expression during the estrous cycle in the cow. Immunohistochemistry was used to quantify the number of arteriolovenous vessels (surrounded with smooth muscle actin-positive smooth muscle cells), capillaries (with von Willebrand Factor-positive... |
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Palavras-chave: Blood vessels; Corpus luteum; ENOS; Luteolysis. |
| Ano: 2010 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2989 |
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| Watanabe, Sho; Shirasuna, Koumei; Matsui, Motozumi; Yamamoto, Dai; Berisha, Bajram; Schams, Dieter; Miyamoto, Akio; 白砂, 孔明; 松井, 基純; 宮本, 明夫. |
| Endothelin-1 (ET-1) is a luteolytic mediator in the bovine corpus luteum (CL), and its action appears to be via endothelin type A receptor (ETR-A). Thus, the aim of the present study was to determine the effect of ETR-A antagonist on PGF(2)alpha-induced luteolysis in the cow. Cows on days 1012 of the estrous cycle were subjected to five intraluteal injections of the ETR-A antagonist LU 135252 in saline or only saline at -0.5, 2, 4, 6, and 8 h after PGF(2)alpha administration (=0 h). Serial luteal biopsies were conducted to determine the expression of mRNA in the luteal tissue. There were no significant differences in the decrease in plasma progesterone (P) concentrations and the mRNA expressions of steroidogenic acute regulatory protein and 3... |
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Palavras-chave: Apoptosis; Blood flow; Corpus luteum; Cow; Endothelin-1. |
| Ano: 2006 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/922 |
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| SHIRASUNA, Koumei; WATANABE, Sho; NAGAI, Kaya; SASAHARA, Kiemi; SHIMIZU, Takashi; RICKEN, Albert M.; SPANEL-BOROWSKI, Katharina; MIYAMOTO, Akio; 白砂, 孔明; 清水, 隆; 宮本, 明夫. |
| Cell-to-cell interaction via cell contact-dependent pathway is essentially important for maintenance and regulation of corpus luteum (CL) integrity and its physiological actions. The objective of the present study was to evaluate the mRNA expression of the cell adhesion molecules (CAMs) that are constituent factors of gap junctions [connexin (Cx) 43] and adherence junctions (VE-, E-, N-cadherin) in two types of endothelial cells from the mid CL and in CL tissue during the estrous cycle and PGF2α-induced luteolysis in the cow. Specific mRNA expression for Cx43 and N-cadherin was detected in cytokeratin-positive (CK+) and cytokeratin-negative (CK-) luteal endothelial cells (EC) and fully luteinized granulosa cells (LGC). E-cadherin mRNA was expressed in... |
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Palavras-chave: Cadherin; Connexin; Corpus luteum; Cow; Luteolysis. |
| Ano: 2007 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2988 |
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| SHIRASUNA, Koumei; SASAHARA, Kiemi; MATSUI, Motozumi; SHIMIZU, Takashi; MIYAMOTO, Akio; 白砂, 孔明; 松井, 基純; 清水, 隆; 宮本, 明夫. |
| Administration of prostaglandin (PG) F2α in cattle during the mid-luteal phase (Days 8-12 of the estrous cycle) drastically reduces the plasma progesterone concentrations and the volume of the corpus luteum (CL). However, PGF2α does not induce luteolysis during the early luteal phase (up to Day 5 of the estrous cycle). To characterize the possible distinct difference in acute response to a luteolytic dose of PGF2α administration, we determined various mRNA expressions in the early and mid CL relating to angiogenesis, vasoactivation and PG-related factors at 30 min after PGF2α injection in cyclic cows. The experiments were conducted on Day 4 (early CL) and Days 10-12 (mid CL). Cows were either injected with 500 μg PGF2α analogue or saline as the control... |
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Palavras-chave: Corpus luteum; Cow; Luteolysis; Prostaglandin F2α. |
| Ano: 2010 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2812 |
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| SHIRASUNA, Koumei; KAWASHIMA, Chiho; MURAYAMA, Chiaki; AOKI, Yuka; MASUDA, Yutaka; KIDA, Katsuya; MATSUI, Motozumi; SHIMIZU, Takashi; MIYAMOTO, Akio; 白砂, 孔明; 川島, 千帆; 増田, 豊; 木田, 克弥; 松井, 基純; 清水, 隆; 宮本, 明夫. |
| The decrease in fertility and conception rates of high-producing dairy cows is one of the major negative impacts for today's producers. The recovery of ovarian activity postpartum is affected by the status of immunity, metabolism and reproduction and plays a critical role in subsequent fertility after parturition in the cow. In the present study we investigated the relationships between polymorphisms in genes relating to the above functions and the first postpartum ovulation as a marker of the recovery of ovarian function in the cow. In immune function related-factors, the occurrence of first postpartum ovulation within 3 weeks in the C/C genotypes of tumor necrosis factor α (TNFα) exon (55.4%) and the A/G genotypes of TNFα promoter (55.4%) was... |
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Palavras-chave: Cow; Ovulation; Polymorphism; Tumor necrosis factor α (TNFα). |
| Ano: 2011 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2990 |
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| BEINDORFF, Nicola; NAGAI, Kaya; SHIRASUNA, Koumei; HERZOG, Kathrin; HOEFFMANN, Katharina; SASAKI, Motoki; BOLLWEIN, Heinrich; MIYAMOTO, Akio; 佐々木, 基樹; 宮本, 明夫; 白砂, 孔明. |
| The present study determined vascular changes in the bovine corpus luteum (CL) at Day 16 (early maternal recognition period) and Day 40 in early pregnancy and compared them to the CL from Day 12 and Day 16 of the estrous cycle. The CLs were analyzed in the central and peripheral regions, where site-depending features of vessels and angiogenic factors are evident. The same protein level of the endothelial cell marker von Willebrand factor was retained in the CL from Day 16 of the estrous cycle to Day 40 of early pregnancy. The protein level of pericytes and smooth muscle cells was determined using smooth muscle α-actin; the level decreased at Day 40 of early pregnancy in both regions of the CL. No significant change in the expressions of vascular... |
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Palavras-chave: Corpus luteum; Cow; Early pregnancy; Endothelial cells. |
| Ano: 2010 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2811 |
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| Registros recuperados: 12 | |
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