BACKGROUND Early mammalian blastomeres are thought to be flexible and totipotent allowing the embryo to overcome perturbations in its organization during preimplantation development. In the past, experiments using single blastomeres from 2-, 4- and 8-cell stage mammalian embryos have provided evidence that at least some of the isolated cells can develop into healthy fertile animals and therefor...

Blastocysts more commonly have a normal karyotype than cleavage-stage embryos do. Moreover, blastocysts have also made a metabolic transition from catabolism and recycling of the oocyte's reserves and resources, processes that fuel the first 3 days of cleavage. Although not all blastocysts are karyotypically equal, it is still to be determined to what extent a mosaic karyotype might be a normal...

BACKGROUND To optimize blastocyst cryopreservation, the prerequisite is to develop a better understanding of factors that influence their survival and implantation potential. Therefore, the aim of the present work was to evaluate, retrospectively, the outcome of blastocyst cryopreservation in a day 2/3 fresh embryo transfer programme. METHODS Two different freezing strategies were compared: a...

Summer heat stress decreases the pregnancy rate in cattle and has been thought to be associated with the early embryonic death caused by the elevation of maternal body temperature. In vitro cultures have been widely used for the evaluation of effects of heat stress on oocytes, fertilization, preimplantation, and embryonic development. Susceptibility to heat stress is present in developmental st...

Early embryonic loss and altered gene expression in in vitro produced blastocysts are believed to be partly caused by aberrant DNA methylation. However, specific embryonic stage which is sensitive to in vitro culture conditions to alter the DNA methylation profile of the resulting blastocysts remained unclear. Therefore, the aim of this study was to investigate the stage specific effect of in v...

Many efforts have been made to develop effective culture conditions for the production of bovine blastocysts. Growth hormone (GH) and glucose are known to affect in vitro embryo development. To improve in vitro culture conditions, the culture medium containing fetal calf serum (FCS) or bovine serum albumin (BSA) was supplemented with GH at various periods of development, and the effects of GH o...

Colony-stimulating factor 2 (CSF2) enhances competence of the bovine embryo to establish and maintain pregnancy after the embryo is transferred into a recipient. Mechanisms involved could include regulation of lineage commitment, growth, or differentiation of the inner cell mass (ICM) and trophectoderm (TE). Experiments were conducted to evaluate regulation by CSF2 of pluripotency of the ICM an...

There are significant advantages to the production of gene-knockout mice directly in mouse strains other than 129. The availability now of ES cells derived from the C57BL/6 mouse strain presents workers with a valuable alternative. A major difficulty, however, is the requirement for BALB/c blastocysts as recipients for ES cell injection. Using standard procedures, few BALB/c blastocysts can be ...

BACKGROUND The development and validation of stem cell therapies using induced pluripotent stem (iPS) cells can be optimized through translational research using pigs as large animal models, because pigs have the closest characteristics to humans among non-primate animals. As the recent investigations have been heading for establishment of the human iPS cells with naïve type characteristics, it...