The developmental capacity of (a) single blastomeres of 4-cell embryos, (Jb) pairs of blastomeres of 8-cell embryos and (c) single blastomeres of 8-cell embryos was studied. The blastomeres were inserted into evacuated foreign zonae pellucidae, embedded in agar, transferred to ligated oviducts of dioestrous ewes, and recovered when their total age was 5-Jto 6̂ days. At lecovery the majority of e...

A method for the production of embryonic stem (ES) cell-embryo chimeras was developed that involves the simple coculture of eight-cell embryos on a lawn of ES cells. After coculture, the embryos with ES cells attached are transferred to normal embryo culture medium and allowed to develop to the blastocyst stage before reimplantation into foster mothers. Although the ES cells initially attach to...

Pregnancy was established by transcervical transfer of embryos from performance mares into recipient mares. Estrus was synchronized between donor (n = 17) and recipient (n = 43) mares. After a greater than or equal to 25-mm follicle was detected, donor mares were bred artificially daily until ovulation. Day of ovulation was recorded. Uterine flushes (n = 111) were performed on donor mares 7 day...

Gibberellic acid (GA3) is a group of plant hormones identified in various plants. The aim of this study was to determine the effects of GA3 on sperm parameters and in vitro fertilization (IVF). Fifty six adult male rats were divided into seven groups as, control, treatment and sham. Following 15, 30 and 45 days of GA3 and methanol alcohol (MA) administration, rats were euthanized and e...

The completely new strategy of pseudophysiological transcomplementary (transcytoplasmic) activation (PP-TCA) of nuclear-transferred oocytes, which had been derived from pWAPhGH-GFPBsd transfected foetal fibroblast cells, was recently applied to the somatic cell cloning of pigs. It resulted in the considerable enhancing not only the cleavage activity of cultured cloned embryos, but also their mo...

In toto mouse embryos were cultivated at embryonic day 8.5 for 26 h with 105, 310 or 620 microM caffeine; 105-310 microM correspond to concentrations transferred by the placenta of heavy caffeine consumers. Failure of neural tube closure, excessive proliferation of neuroepithelial cells and premature evagination of telencephalic vesicles were present in 50% of treated embryos. When reaching the...

Mouse eggs were activated with hyaluronidase in vitro and subsequently transferred to the oviduct. In the female reproductive tract they formed morulae and blastocysts which died soon after implantation. Haploid blastocysts were transferred beneath the kidney capsule and here some formed disorganized egg-cylinder structures in a week. Morulae and blastocysts from haploid and diploid parthenogen...

BACKGROUND Cell-cell communication and adhesion are essential for the compaction process of early stage embryos. The aim of this study was to develop a non-invasive objective calculation system of embryo compaction in order to test the hypothesis that embryos with a larger mean contact surface result in a higher live birth rate compared to embryos with a lower mean contact surface. METHODS Mu...

Embryos were transferred between Meishan and Landrace x Large White (control) gilts on Day 4 or 5 to establish approximately equal numbers of all four possible combinations of donor breed and recipient breed. The breed of the donor gilt significantly (P less than 0.01) affected embryo survival with 44.5% of transferred Meishan embryos and 69.6% of transferred control embryos surviving to Day 30...