Abstract. The objective of this study was to examine whether high concentrations of epidermal growth factor (EGF) and/or insulin-like growth factor I (IGF-I) would have a beneficial effect on bovine embryo development in vitro and to obtain normal calves by using an ovum pick up method and embryo culture in a chemically defined medium. When compared with controls, EGF (100 or 200 ng/ml) or IGF-I (50 or 100 ng/ml) significantly increased the rate of embryos that developed into blastocysts during an 8-day culture after the in vitro fertilization of oocytes obtained from ovaries from a slaughterhouse. IGF-I induced a dose-dependent increase in cell number in both the inner cell mass and the trophectoderm, whereas EGF stimulated proliferation only in the inner cell mass. A combination of EGF (100 ng/ml) and IGF-I (50 ng/ml) produced an additive effect, and embryos developed into blastocysts at a comparatively high rate (27.9%) compared with controls (12.0%). A similar rate of development was achieved using a combination of EGF and IGF-I in the culture of embryos following ovum pick up by ultrasound-guided transvaginal follicular aspiration and in vitro fertilization, and 5 blastocysts that developed after the culture were transferred into uteri; two embryos implanted, and normal calves were born. These results suggest that the combined use of EGF and IGF-I makes bovine embryo culture in a chemically defined medium a practical and useful procedure for producing blastocysts, and its application to embryo culture following ovum pick up and in vitro fertilization could be useful for producing normal calves. Key words: Bovine embryo, Chemically defined medium, Epidermal growth factor (EGF), Insulin-like growth factor I (IGF-I), Ovum pick up (OPU) (J. Reprod. Dev. 58: [140][141][142][143][144][145][146] 2012) R ecently, a number of calves have been produced by the ovum pick up (OPU) method and in vitro culture (IVC) systems. Since the OPU method can be repeatedly applied to the same cow and can be used in pregnant [1] or problem cows in which embryos have not been obtained by uterine flushing after artificial insemination [2], this technology is effective for facilitating the improvement of domestic animals.An IVC system is necessary for the OPU method. Since successful pregnancy by transfer of embryos following the OPU method and in vitro fertilization has been confirmed [3], different protocols and medium conditions for oocyte maturation and embryo development have been tested [4][5][6][7]. However, there are some problems associated with the IVC system, such as a skewed sex ratio [8,9] or large offspring syndrome [10,11]. It has been suggested that factors in the culture medium such as serum used for embryo development may be involved in these problems. Fetal bovine serum (FBS) is widely employed as a supplement in the media used for culturing in vitro fertilized bovine embryos, but the subsequent rate of development of the fertilized oocytes to the blastocyst stage is known to vary among serum lots. There is thus a...

Dependence of band alignments at interfaces between CdS (grown by chemical bath deposition) and Cu(In 1-x Ga x )Se 2 (CIGS) (by conventional 3-stage co-evaporation) with 0.2

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Change of electronic structure of superconducting (Cu, C)-1201 thin films grown by pulsed laser deposition with superconducting critical temperature Tc has been characterized by means of in situ photoemission spectroscopy. The finite spectral weight at the Fermi level in the valence band of (Cu, C)-1201 superconducting thin films and a rigid-band-like approach of the main peak of the valence band toward the Fermi level with a rise of Tc has been observed, which reveals hole-doping-induced superconductivity of this system. The obtained Ba 4d and Cu 2p signals with an increase of Tc suggest excess oxygen should be introduced around Ba ions in the early stage of the emergence of superconductivity. Then, they should be preferentially introduced around Cu ions. The changes of core signals with Tc and comparisons of the obtained data with infinite-layer and other cuprate superconductor compounds suggest that the (Cu, C)–O charge reservoir in this system is in the heavily hole-doped state, similar to that of the Cu–O chain in YBa2Cu3O7−δ.

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