A chimera is an animal that has two or more populations of genetically distinct cells that originated in different embryos, fetuses, or individuals of the same or different species. During recent decades, embryos, the inner cell mass (ICM), teratocarcinoma stem cells, embryonal carcinoma stem cells, embryonic stem (ES) cells (ESCs), primordial germ cells, spermatogonial stem cells, extraembryon...

during spring, summer and winter seasons, sistani donor cows, with normal reproductive status, were superovulated and embryos were recovered non-surgically on day 7. grade a blastocyst embryos were either transferred fresh (spring) or frozen (summer and winter). recovered embryos during summer and winter were exposed to glycerol and frozen using conventional method. during spring season, recipi...

Background: Success in assisted reproductive techniques is raising hope for many infertile couples, but as in these techniques many embryos are made, there is no choice other than cryopreservation of the not-transferred embryos. Along with development of these techniques, the number of In-vitro made embryos is rising and the number of transferred embryos is decreasing to prevent multiple gestat...

Birch (Betula platyphylla Suk.) is a deciduous tree with medicinal and ornamental value. During the process of genetic transformation, somatic embryos do not easily develop into transgenic plants, which limitation in breeding. The Arabidopsis thaliana WUSCHEL (AtWUS) gene, transcription factor, plays an important role maintaining regulating stem cell characteristics, determines whether populati...

OBJECTIVES/HYPOTHESIS The development of a simple, reliable, and cost-effective animal model greatly facilitates disease treatment. We aimed to establish a rapid, simple, and reproducible live zebrafish vestibular schwannoma xenograft model for antitumor drug screening. METHODS We optimized each of the following conditions for tumor cell xenografts in zebrafish larvae: larval stage, incubatio...

The effect of fetal and maternal genotype on embryo survival was studied in two lines of mice from the same base population: line E, selected for high embryo survival, and line CN-, selected for small litter size. Embryos were collected at 3.5 days postcoitus from normally mated donors of both lines and were transferred to the uteri of 2.5-day pseudopregnant recipients from each line. The numbe...

Background: While it is possible to routinely cryopreserve embryos from several mammalian species, the cryopreservation of embryos has largely been limited by their high sensitivity to chilling injury. Many factors such as the stage of embryonic development, cryoprotectant toxicity, the composition of the vitrification solution and cooling and warming rates can influence survival of embryos aft...

There is an ever increasing trend in reproductive medicine to reduce the intensity of ovarian stimulation for in vitro fertilization (IVF) and to restrict the number of embryos that are transferred into the uterine cavity. Recent findings suggest that the magnitude of ovarian stimulation affects the proportion of euploid embryos. As a result of the restriction in the number of embryos transferr...

BACKGROUND This retrospective study analysed the outcomes of 339 embryo transfers on either day 3 (n = 97) or day 4 (n = 242), and proposed a grading system for morula/compact embryos. METHODS The morula/compact embryo grading was based on: (i) the proportion of blastomeres undergoing the compaction process; (ii) the morphology of the compacted multicellular mass; (iii) the embryo quality on ...

The somatic cell nuclear transfer (SCNT) technique is the most popular method for producing genetically modified pigs, but its efficiency depends upon a number of factors. In the present study, we attempted to generate transgenically cloned Guangxi Bama mini-pigs--which possess great potential for modeling human diseases--through genetic modification of fibroblasts, followed by SCNT and embryo ...