In vitro fertilisation (IVF) is the process by which oocytes and sperm are mixed in a petri dish, allowing fertilisation to occur outside the mother's body. Similarly to the genetic advantage obtained using artificial insemination with respect to the paternal parent, IVF affords the ability to more stringently select the maternal parent. Oocytes from one valuable female can be transferred into ...

Wood properties and growth were measured on breast-height cores and on disks collected at different heights from a thinned and fertilized midrotation loblolly pine (Pinus taeda L.) plantation in the lower Coastal Plain of North Carolina. The study was laid out in a randomized complete-block design receiving four levels of nitrogen (N) fertilizer: unfertilized control and 112, 224, and 336 kg/ha...

Oocyte recovery guided by transvaginal ultrasonography has been introduced into in vitro fertilisation units and compares favourably with laparoscopic oocyte recovery. 2 The transition from laparoscopy to ultrasonography may, however, account for part of this difference-for example, anaesthetic requirements and risks of pneumoperitoneum are reduced. In Oxford the in vitro fertilisation unit is ...

Receptor protein-tyrosine phosphatases (RPTPs) are key players in Drosophila development. To study the role of RPTPs in vertebrate development, we have cloned zebrafish (zf) RPTPs, including RPTP alpha (RPTPalpha), RPTP sigma (RPTPsigma) and LAR. These three RPTPs are broadly transcribed in early development. At 24h post fertilisation (hpf), all three genes are expressed in the nervous system i...

Pre-implantation genetic diagnosis (PGD) is the examination in vitro of an embryo (or an egg cell prior to fertilisation) in order to exclude a genetic condition in case a very high risk of that condition is known. PGD can only be used in combination with in vitro fertilisation (IVF). If a genetic abnormality in the form of a monogenetic disease such as Huntington’s disease or cystic fibrosis o...

Mapping epigenetic modifications and identifying their roles in the regulation of spermatogenesis and embryogenesis are essential for gaining fundamental medical understandings and for clinical applications. More and more evidence has shown that specific epigenetic modifications are established during spermatogenesis, which will be transferred into oocyte via fertilisation, and play an importan...

Assisted reproductive technology (ART) encompasses all medical intervention used to assist people becoming parents, mainly but not solely as a result of infertility. In vitro fertilisation (IVF) is the cornerstone of ART. It involves stimulating the ovaries, retrieving and culturing oocytes which are then inseminated with capacitated spermatozoa. The embryo is cultured and transferred into the ...