The aim of this study was to review the experience and outcomes of assisted reproduction cycles with embryos grown up to day 5 of development, comparing different parameters according to the ages of the patients. We retrospectively studied 1,874 assisted reproduction cycles where embryo culture was extended up to the fifth or sixth day of development. All IVF and ICSI cycles were included, comp...

BACKGROUND Single blastocyst transfer has the advantage of maximizing the fresh single pregnancy rate. However, in patients with a low number of good quality embryos on day 3, it remains unclear whether immediate embryo transfer or further embryo culture with blastocyst transfer is the most preferable option. METHODS A retrospective cohort study was carried out in which the outcome of 590 fre...

For fertility patients undergoing in vitro fertilization (IVF), blastocyst culture brings a number of potential advantages over laboratory techniques leading to traditional cleavage-stage embryo transfer. Because day 2-3 embryos normally should transit the oviduct only, their direct exposure to an intrauterine microenvironment is physiologically inappropriate. This mismatch is obviated by blast...

The present study was designed to evaluate the effect of activin-A during the in vitro oocyte maturation (IVM) and in vitro embryo culture (IVC) on nuclear maturation, blastocyst yield and blastocyst quality of prepubertal goat oocytes. In Experiment 1, three groups of oocytes were used during the IVM of prepubertal goat oocytes to determine the optimal concentration of recombinant human activi...

Interspecies somatic cell nuclear transfer (iSCNT) is a useful method to preserve endangered species and to study the reprogramming event of a nuclear donor cell by the oocyte. Although several studies of iSCNT using murine cells and bovine oocytes have been reported, the development of murine-bovine iSCNT embryos beyond the 8-cell stage has not been successful. In this paper, we examined the d...

Establishment of pregnancy in ruminants requires blastocyst growth to form an elongated conceptus that produces interferon tau, the pregnancy recognition signal, and initiates implantation. Blastocyst growth and development requires secretions from the uterine endometrium. An early increase in circulating concentrations of progesterone (P4) stimulates blastocyst growth and elongation in ruminan...

Telomerase, a ribonucleoprotein, has been described as an essential component of highly proliferative cells as it stabilizes the telomeres and avoids cellular senescence. The objective of this study was to modify the polymerase chain reaction-based telomeric repeat amplification protocol to detect telomerase activity in the single cell and to characterize the activity expressed in the human ooc...

The mechanism of embryonic polarity establishment in mammals has long been controversial. Whereas some claim prepatterning in the egg, we recently presented evidence that mouse embryonic polarity is not established until blastocyst and proposed the mechanical constraint model. Here we apply computer simulation to clarify the minimal cellular properties required for this morphology. The simulati...

INTRODUCTION The first step in human implantation is the attraction of the blastocyst to the endometrium. We aimed to study attraction of the human blastocyst to the endometrium, and how this process is accomplished by chemokines secreted by the endometrium. MATERIALS AND METHODS Blastocyst trophectoderm cells and other trophoblast lineage cells were subjected to attraction assays by IP-10 an...