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It is important to understand ovarian physiology when developing an artificial insemination (AI) protocol. Brown bears (Ursus arctos) have a breeding season from May to July, although the type of estrus (polyestrus or monoestrus) is still contested. The present study aimed to define the ovarian dynamics, including follicular waves and ovulatory follicle size, and estrus type in brown bears. Six brown bears were used for ovarian ultrasonography; four were observed between April and October (before the start and after the end of the breeding season) and two in June (breeding season). In addition, we attempted to induce ovulation by administering a gonadotropin releasing hormone (GnRH) agonist. We observed follicular development in April in four bears, but follicles did not develop to greater than 6.0 mm in diameter until May. Thereafter, a group of follicles developed to more than 6.0 mm and grew as dominant follicles, except in one bear. After ovulation and subsequent corpus luteum (CL) formation, the follicular waves disappeared. Furthermore, in three bears treated with GnRH, follicles between 8.2 to 11.2 mm in diameter at the time of treatment ovulated and formed CLs. In two bears, follicles between 5.8 to 8.8 mm ovulated spontaneously within the observation interval. Our results suggest that brown bears may be monoestrous animals. Therefore, AI can only be performed once during the breeding season. Our results also suggest that dominant follicles larger than 8.0 mm are a suitable size for inducing ovulation.

In dairy cows, low fertility caused by summer heat stress continues into the cooler autumn season. This can be caused by impaired oocyte quality in small growing follicles during summer. Here, we subjected oocyte–cumulus–granulosa complexes (OCGCs) derived from early antral follicles (0.5–1 mm) to in vitro growth (IVG) culture under two different temperature settings (the control and heat shock groups), and evaluated effects of heat exposure on growth and developmental competence of oocytes, factors affecting the developmental competence of oocytes (steroidogenesis of granulosa cells, oxidative stress in oocytes, and cell-to-cell communication between oocytes and somatic cells). Oocyte diameters after culture were smaller in the heat shock group. Although nuclear maturation and cleavage rates were similar between the groups, blastocyst rates were lower in the heat shock group (0.0%) than in the control group (27.7%), and reduced glutathione (GSH) levels in oocytes were lower in the heat shock group. Supplementation of cysteine, which stimulates GSH synthesis, increased GSH level and improved blastocyst rate of heat shocked oocytes (27.9%). These results suggest that heat exposure impairs the growth and developmental competence of oocytes in early antral follicles through GSH depletion, which can induce low fertility during summer and the following autumn.

Advance Publication, Here, we describe a simplified procedure for embryo production in the Japanese black cow that uses a single caudal epidural injection of follicle-stimulating hormone (FSH). First, we compared the efficiency of superovulation for in vivo embryo production between conventional multiple FSH treatment (control, n = 10) and single epidural administration (epidural, n = 5). The number of transferable blastocysts was similar between control and epidural groups (4.7 ± 3.5 and 9.0 ± 6.0, respectively). Next, we compared in vitro embryo production by ovum pick-up and in vitro fertilization (OPU-IVF) between control (n = 12) and epidural groups (n = 12). The rate of development to transferable blastocysts was higher in the epidural group than in the control (23.3 vs. 10.5%, P < 0.001). In conclusion, a single epidural administration of FSH can induce follicular development comparable to that of the conventional superovulation protocol and may improve the productivity of OPU-IVF.

Bone morphogenetic protein-4 (BMP-4) inhibits luteinization of granulosa cells during in vitro growth (IVG) culture of bovine oocytes; however, oocytes derived from a 12-day IVG were less competent for development than in vivo-grown oocytes. We herein investigated whether an extended IVG culture with BMP-4 improves oocyte growth and development to blastocysts after in vitro fertilization. Oocyte-granulosa cell complexes (OGCs) were cultured for 14 or 16 days with BMP-4 (10 ng/mL), while a 12-day culture with BMP-4 served as the in vitro control. OGC viability was maintained for the 16-day culture with BMP-4 (83.2%), but was significantly lower without BMP-4 (58.9%) than the control (83.0%). Prolong-cultured oocytes at 16 days had statistically greater diameter (114.6 μm) than the control (111.7 μm). IVG oocytes with BMP-4 for the 16-day culture had a similar nuclear maturation rate to the control (approximately 67%); however, blastocyst rates in BMP-4 treated oocytes of 14- (1.8%) and 16-day (0%) IVG were statistically lower than that of 12-day IVG (9.0%). In conclusion, BMP-4 maintained OGC viability and promoted oocyte growth in a prolonged culture, but impaired the developmental competence of oocytes. Prolonged culture may not be an appropriate strategy for enhancing the developmental competence of IVG oocytes.

To clarify the relationship between ovarian reserve and the developmental competence of bovine oocytes, oocyte-granulosa complexes (OGCs) collected from early antral follicles (≤1 mm) in ovaries with high (≥25) and low (

In this study, to clarify the relationship between ovarian reserve and oocyte quality, cumulus-oocyte complexes (COCs) were collected repeatedly by ovum pick-up (OPU) from cows with high and low antral follicle counts (AFCs) at short (3–4 days) and long (7 days) intervals, and COC morphologies and oocyte fertilizability were examined. The relationship between AFC and follicular growth after OPU was also investigated. Cows showing AFC of ≥30 in at least one OPU session were grouped into the high-AFC group. At a short interval, follicular sizes and COC morphologies were similar between the different AFC groups. However, the normal fertilization rate was higher in the high-AFC group than in the low one, although total penetration rates were similar. At a long interval, the percentage of COCs with poor morphology in the high-AFC group was higher and the normal fertilization rate was lower than in the low one. In the low-AFC group, normal fertilization rates at short and long intervals were similar, and mean follicular size became larger at a long than at a short interval. However, mean follicular sizes at short- and long-interval OPU were similar in the high-AFC group. In conclusion, it is suggested that oocytes derived from cows with high AFC had higher fertilizability than those from cows with low AFC when OPUs were performed at a short (3–4 days) interval. However, oocyte quality in high-AFC cows was impaired by long-interval (7 days) OPU, possibly due to the degradation of follicles.

The School of Veterinary Medicine of Hokkaido University has been trying to improve the teaching capabilities of the faculty members by using funds from the Ministry of Education, Culture, Sports, Science and Technology (Ministry of Education). In the 2007 academic year, a program for improvement of clinical education in herd medicine was funded by the Ministry of Education. Herd medicine is an area of veterinary medicine that aims to improve both the health and productivity of livestock through the management of their food and housing. Japanese veterinary education is at least 10 years behind North America and the EU countries in this area. The program sends faculty members to veterinary schools in North America and EU countries to learn the advanced education system for herd medicine. Newly appointed faculty members are also expected to participate in clinical work at the university hospital to gain experience and to learn teaching skills based on clinical cases. The experience of the individual faculty members will be shared with other members of our school and also with the members of other veterinary schools in Japan by organizing meetings and distribution of reports.

Effects of isolation and vitrification protocols on follicular survival after warming were examined. Mouse preantral follicles enzymatically or mechanically isolated from ovaries of 12-day-old mice were exposed either to 2 M ethylene glycol (EG) for 2 or 5 min, or to ascending concentrations (0.15 then 0.3 M) of raffinose for 2 or 5 min each (2-2 and 5-5 min). They were then exposed to a vitrification solution (VS) composed of 6 M EG and 0.3 M raffinose for 0.5, 1, or 2 min before vitrification. Mechanically isolated follicles showed higher survival than enzymatically isolated follicles, regardless of periods of exposure to EG or raffinose and subsequent exposure to VS. After 10 days of culture, follicular growth and maturational ability of oocytes derived from vitrified follicles exposed to 2 M EG for 5 min and to VS for 1 min were higher than those from follicles exposed to raffinose solutions for 2-2 min and to VS for 1 min. Histological evaluation revealed that exposure of preantral follicles to raffinose solutions caused cytoplasmic vacuolation in granulosa cells which could be due to cellular shrinkage during dehydration; whereas, exposure to 2 M EG induced morphological alterations in follicles only to a lesser extent.

宇宙航空研究開発機構(JAXA)は、データ中継技術衛星DRTS経由で計測した衛星間測距データ(4-way追跡データ)を用いて、軌道決定技術の実証実験を行っている。本論文では、4way追跡データを用いた地球周回衛星の軌道決定実験の主要な成果を報告する。また、2007年打ち上げ予定の月周回衛星(SELENE)では、月を周回する小型衛星経由で月裏側の4-wayドップラを取得する計画である。4-wayドップラがSELENE軌道決定・予報精度に与える影響についても紹介する。, The Japan Aerospace Exploration Agency (JAXA) has been studying the feasibility of orbit determination technology with satellite-to-satellite (four-way) tracking data using the DRTS (Date Relay Test Satellite) which was launched in 2002. The orbit determination was performed in batch processing mode, and showed that the accuracy level is equivalent to the results by tracking data from ground network stations. This paper presents the overview of JAXA's experiments on orbit determination using four-way tracking data of the DRTS user satellites such as the ADEOS (Advance Earth Observing Satellite)-2 and the ALOS (Advanced Land Observing Satellite). The application of this technologies to the SELENE (SELenological and Engineering Explorer) orbiting the moon is also presented., 資料番号: AA0063223014, レポート番号: JAXA-SP-06-015

本稿では、月重力場モデル改良には量が不足していると思われるSELENE1ヶ月間のドップラデータでも、軌道決定精度向上には有効である可能性を示す。, 資料番号: AA0049122114

ADEOS-2の軌道決定実験において、疑似距離と搬送波位相から決定される軌道は、SLRから決定される軌道に比べ衛星進行方向に約5mオフセットしていることが判明した。この状態では、軌道決定精度は数メータであり、世界的に恥ずかしいレベルであった。オフセットの原因を解明するため、多くの可能性を評価した。最終的にGPS受信機内部の処理のミスであることをつきとめた。具体的には、疑似距離のタイムタグと搬送波位相のタイムタグの間に1msの差が発生していた。原因が判明したので、疑似距離を補正することが可能となった。補正した結果、ADEOS-2に対する、軌道決定精度は約40cm(RMS)まで向上させることに成功した。, 資料番号: AA0049122115

1980年代半ば、静止衛星の軌道変換、運用終了衛星のリエントリ、宇宙往還機のランデブーやドッキング時における地上からのリアルタイム軌道把握要求があった。当時の運用システムは、慣性飛行の衛星に対するバッチ軌道推定機能しかなかったため、軌道変換後の軌道は数時間のレンジングののち把握していた。そこで、宇宙航空研究開発機構JAXA(当時、宇宙開発事業団)では、1987年より実時間軌道推定プログラムRTEP(Real-time Trajectory Estimation Program)の開発に着手した。本論文は、RTEPの概要および2002年のデータ中継技術衛星(DRTS)での運用結果を報告する。, 資料番号: AA0047899152

資料番号: AA0047899151

アストロダイナミクスシンポジウム (2009年7月30-31日. 宇宙航空研究開発機構宇宙科学研究本部)), Workshop on JAXA Astrodynamics and Flight Mechanics, 2009 (July 30-31, 2009. Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA)), Sagamihara, Kanagawa Japan, ASTRO-GはVLBIを利用した天文観測衛星であり、非常に高精度な位置決定が必要となる。軌道決定方法として、GPSデータによる軌道決定を想定している。本論文では、ASTRO-Gの形状が複雑であり、衛星のモデル化が難しいことから、力学モデルに焦点を当て、力学モデル誤差が軌道決定精度に与える影響について調査した。調査結果から、太陽輻射圧モデル誤差が軌道決定精度へ与える影響は数10cmと非常に大きく、ミッション要求精度を達成するためには、太陽輻射圧モデルの高精度化（1%程度）やSLRを利用する必要がある。, ASTRO-G is a radio astronomy observation satellite using VLBI and will require centimeter level orbit determination precision. The Orbit determination method for ASTRO-G is the orbit determination with GPS satellites. In this paper, we assess the effect of orbit determination accuracy for the error of dynamical model, because a complex shape of ASTRO-G makes it difficult to make dynamical model precisely. From the result, the effect that the error of solar radiation pressure model gives orbit determination accuracy is very large and the size of the position error is 10cm order. In order to achieve the required accuracy form mission, it requires solar radiation pressure model with high accuracy (approximately 1% level) and the utilization of the SLR data should also be considered., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA0064734040

Superovulation causes detrimental effects, including embryonic loss and implantation failure. This study determined potential roles for insulin-like growth factor (IGF-I) in uterine environment regulation and preimplantation development, in conjunction with the detrimental effects of superovulation in the rat. IGF-I may be beneficial to preimplantation embryonic development. IGF-I stimulated embryonic development and metabolism in vitro and increased the rate of implantation and fetal development when the blastocysts were transferred into a receptive uterus. However, IGF-I may be involved in embryonic loss following superovulation, by perturbing the uterine environment. Superovulation enhanced uterine IGF-I action from day 1 to 3 of pregnancy and reduced its action on days 5 and 6. Uterine luminal fluid from the uterus exposed to increased IGF-I action from day 1 to 3 was detrimental to embryonic development. This uterine luminal fluid had altered electrolyte composition that is similar to that observed following superovulation. Anti-IGF-I antibody restored superovulationinduced alterations in cations, suggesting that IGF-I may partially mediate this effect of superovulation. Superovulation-induced alterations in IGF-I action may adversely affect decidualization, a critical step in implantation. High IGF-I levels from day 1 to 3 and low levels from day 3 to 5, inhibited deciduoma formation. Alterations in IGF-I action after day 5 had no effect, suggesting a role for IGF-I in uterine sensitization. The role of IGF-I in decidualization may be complex. IGF-I cannot be substituted for growth hormone (GH) and thyroxine (T4) during decidualization, but altered deciduoma formation and alkaline phosphatase (ALP) activity in the GH and T4-dependent manner. IGF-I either stimulated or inhibited deciduoma formation and ALP activity, depending upon concentration and treatment period. IGF-I stimulated basal ALP activity but inhibited prostaglandin E2-stimulated ALP activity in the endometrial stroma cells. In conclusion, IGF-I may play an important role in the maintenance of a receptive uterine environment for embryonic development and the regulation of decidualization. Embryonic loss and failure of implantation following superovulation may be partially attributed to disturbances in uterine IGF-I action as observed in this study.