INTRODUCTION In the previous paper of this series (McLaren & Michie, 1956) we described an experiment in which fertilized mouse eggs were transferred to the left uterine horn of recipient foster-mothers which were themselves pregnant with eggs of their own. Over the range tested (0-18 eggs), as the number of fertilized eggs transferred to the recipient female was increased, the number of embryo...

The relationship between embryo and corpus luteum was studied in an experiment on Barbari goats which were made unilaterally pregnant by embryo transfer 5 days after oestrus. Two embryos were transferred to each recipient whose luteal stage was coinciding with that of the donor. The site of transfer was either ipsilateral uterine horn (group I) or contralateral uterine horn (group II). The "ips...

Background Mesenchyme stem cells (MSCs) are one of the widely used sources in tissue engineering and efficacy of cultural environment. In this survey, rat stem cells are used as coculture. Owing to main obstacle of embryo culture in the lab medium, the survival of embryo in lab is low in comparison with that of normal conditions. The purpose of this research is the survey of fertilization and c...

background: gnrh agonist administration in the luteal phase has been suggested to beneficially affect the outcome of intracytoplasmic sperm injection (icsi) and embryo transfer (et) cycles. this blind randomized controlled study evaluates the effect of gnrh (gonadotropine releasing hormone) agonist administration on icsi outcome in gnrh antagonist ovarian stimulation protocol in women with 2 or...

We studied the developmental potential of single blastomeres from early cleavage mouse embryos. Eight- and sixteen-cell diploid mouse embryos were disaggregated and single blastomeres from eight-cell embryos or pairs of sister blastomeres from sixteen-cell embryos were aggregated with 4, 5 or 6 tetraploid blastomeres from 4-cell embryos. Each diploid donor embryo gave eight sister aggregates, w...

As the success rates of IVF clinics improve, one of the adverse consequences is the increased incidence of twins, due largely to the number of embryos transferred. Even if the number of embryos transferred is restricted to two, the twinning rate can exceed 40% of the pregnancies. An obvious way to reduce this high twin rate would be to transfer only one embryo. This would require that cryoprese...

Most of the microspore-derived embryos can not regenerate normally in rapeseed. The effects of gibberellins (GA3), abscisic acid (ABA), and embryo desiccation on normal plantlet regeneration were studied. The donor plants were grown in a growth chamber at day/night temperatures of 15/10˚C with a 16/8h photoperiod, respectively. Microspores were isolated from whole buds of 2.5-3.5mm in length, c...

Uneven blastomere cleavage in human embryos of 'good morphology', i.e. those normally used for transfer, is a phenomenon which has been poorly investigated. The main objective in this study was to probe deeper into the aetiology behind previous findings that embryos with uneven cell cleavage have a lower developmental capacity in comparison with evenly cleaved embryos. Our hypothesis was that u...

BACKGROUND Fluorescence in situ hybridization (FISH) is the most widely used method for detecting unbalanced chromosome rearrangements in preimplantation embryos but it is known to have several technical limitations. We describe the clinical application of a molecular-based assay, array comparative genomic hybridization (array-CGH), to simultaneously screen for unbalanced translocation derivati...