This present review describes some differences and similarities between bovine embryos produced in vivo and in vitro. The first part outlines the respective environments during maturation, fertilisation and early embryonic development of the two types of embryos and compares their morphological, biochemical and genomic characteristics. Results from comparative studies on embryo metabolism and g...

BACKGROUND Focus on the hatching process has so far been in the field of fresh embryos. Cryopreserved-thawed embryos have a lower rate of pregnancy than fresh embryos, which might be due to hardening of the zona pellucida. METHODS During a 2 year period, a prospective randomized study enrolling 253 cryopreserved-thawed cycles was performed on day 2 embryos. Pseudorandomization to assisted hat...

BACKGROUND It is generally acknowledged that the outcomes of IVF treatments are correlated between repeat cycles in the same couple and that these effects need to be allowed for in the analysis of such treatments. However, there are few studies that have attempted to estimate the magnitude of these effects or their clinical consequences. METHODS We use the embryo-uterus model, extended to inc...

This study was carried out to establish an appropriate condition for the efficient cryopreservation of the mouse pronuclear embryo. In vitro cryopreservation of pronuclear embryos was carried out by slow freezing or vitrification methods and development rate of 2-cell, blastocyst and hatched blastocyst was measured as well as survival rate of the thawed pronuclear embryo. After slow freezing, v...

OBJECTIVE To evaluate and compare the laboratory and clinical outcomes of vitrification with slow-freezing method for cryopreservation of embryos and blastocysts in an in-vitro fertilisation programme. DESIGN Retrospective analysis of all the 104 cycles of frozen embryo and blastocyst replacements from 2003 to 2008 and all the 149 cycles with embryos or blastocysts for vitrification from 2006...

BACKGROUND Cryopreservation of zebrafish embryos is still an unsolved problem despite market demand and massive efforts to preserve genetic variation among numerous existing lines. Chilled storage of embryos might be a step towards developing successful cryopreservation, but no methods to date have worked. METHODS In the present study, we applied a novel strategy to improve the chilling toler...

Oocyte intracellular lipids are mainly stored in lipid droplets (LD) providing energy for proper growth and development. Lipids are also important signalling molecules involved in the regulatory mechanisms of maturation and hence in oocyte competence acquisition. Recent studies show that LD are highly dynamic organelles. They change their shape, volume, and location within the ooplasm as well a...