Aneuploidy in human eggs is the leading cause of pregnancy loss and several genetic disorders such as Down syndrome. Most aneuploidy results from chromosome segregation errors during the meiotic divisions of an oocyte, the egg's progenitor cell. The basis for particularly error-prone chromosome segregation in human oocytes is not known. We analyzed meiosis in more than 100 live human oocytes an...

Reprogramming somatic cells into pluripotent embryonic stem cells (ESCs) by somatic cell nuclear transfer (SCNT) has been envisioned as an approach for generating patient-matched nuclear transfer (NT)-ESCs for studies of disease mechanisms and for developing specific therapies. Past attempts to produce human NT-ESCs have failed secondary to early embryonic arrest of SCNT embryos. Here, we ident...

Rat oocytes can be produced artificially by superovulation. Because some strains show low sensitivity to superovulation treatment, in vitro maturation is an alternative method to produce numerous matured oocytes. Furthermore, establishment of an in vitro maturation system with simple culture conditions is cost effective and leads to easy handling of oocytes. This study examined developmental ab...

The history of in vitro maturation (IVM) of mammalian oocytes, especially of human oocytes, holds a special place for Robert Edwards. He was the first to comprehensively examine and demonstrate maturation of human oocytes in vitro and in so doing he changed the course of medicine by fertilizing them in vitro. In reviewing his contribution, we have examined the state of the field at the time and...

OBJECTIVE To determine the permeability of human metaphase II oocytes to ethylene glycol and water in the presence of ethylene glycol, and to use this information to develop a method to vitrify human oocytes. DESIGN An incomplete randomized block design. SETTING A university-affiliated assisted reproductive center. PATIENT(S) Women undergoing assisted reproduction in the Center for Reprod...

BACKGROUND There is an increased incidence of rare imprinting disorders associated with assisted reproduction technologies (ARTs). The sex-specific epigenetic modifications that are imposed during gametogenesis act as a primary imprint to distinguish maternal and paternal alleles. The most likely candidate for the gametic mark is DNA methylation. However, the timing of DNA methylation acquisiti...

BACKGROUND In vitro maturation (IVM) of oocytes is a promising technique to reduce the costs and avert the side effects of gonadotrophin stimulation for IVF. The pregnancy rates from oocytes matured in vitro are still lower than those of in vivo stimulation cycles, indicating that optimization of IVM remains a challenge. Recently, it was demonstrated that LH exerts its action on ovulation, at l...

BACKGROUND In vitro maturation (IVM) of human oocytes is an emerging procedure quickly incorporated into the world of assisted reproductive technologies. As an effective method of in vitro maturation, several studies have reported the critical role of differentions on activating the complex process involved in both gamete maturation and fertilization. OBJECTIVE In this study, we supplemented ...