Unfertilized oocytes after c-IVF may fail to form pronuclei due lack of sperm penetration. For patients who do not obtain fertilized by c-IVF, intracytoplasmic injection (ICSI) is the only hope for fertilization. However, ICSI necessarily result in fertilization, even though are definitely injected. has been investigated extensively, but few reports on unfertilized have published. To clarify ca...

Sixty unfertilized human oocytes and two fresh polar bodies were karyotyped by spectral karyotyping (SKY). The oocytes were provided by 29 women ranging from 30 to 42 yr of age. The mean hybridization efficiency for oocytes was 95.2% (60/63). Nondisjunction of bivalent chromosomes (13.3%) and predivision of sister chromatids at meiosis I (3.3%) were unequivocally determined by analysis first wi...

BACKGROUND Maternal ageing is the only aetiological factor unequivocally linked to aneuploidy. Two mechanisms seem to explain these abnormalities in oocytes: non-disjunction and premature unbalanced separation of sister chromatids (PSSC). Previous studies of unfertilized oocytes argue for a major role of PSSC in the aetiology of aneuploidy for women of advanced age, but in vitro ageing of the o...

A total of 341 fertilized and 37 unfertilized oocytes from 63 intracytoplasmic sperm injection (ICSI) treatment cycles were included for retrospective assessment using the Embryoscope time-lapse video system. The second polar body (pb2) extrusion occurred at 2.9±0.1 h (range 0.70-10.15 h) relative to sperm injection. All oocytes reduced in size following sperm injection (p<0.05) with shrinkage ...

DNA polymerases from Xenopus laevis oocytes, unfertilized eggs, and kidney cells grown in culture have been characterized. The same three major DNA polymerase activities are present in all cell types examined. We attempt to relate the characteristics of amphibian enzymes to those of mammalian polymerases.

In human in-vitro fertilization (IVF)-embryo transfer, the in-vitro culture environment differs from in-vivo conditions in that the oxygen concentration is higher, and in such conditions the mouse embryos show a higher concentration of reactive oxygen species (ROS) in simple culture media. ROS are believed to cause damage to cell membranes and DNA fragmentation in somatic cells. This study was ...

The animal-vegetal (A-V) axis is already set in unfertilized eggs. It plays crucial roles in coordinating germ-layer formation. However, how the A-V axis is set has not been well studied. In ascidians, unfertilized eggs are already polarized along the axis in terms of cellular components. This polarization occurs during oocyte maturation. Oocytes within the gonad have the germinal vesicle (GV) ...

BACKGROUND The assembly of nuclear pore complexes (NPC) and their cytoplasmic stacks, annulate lamellae (AL), promote normal nucleocytoplasmic trafficking and accompany pronuclear development within the mammalian zygote. Previous studies showed that a percentage of human oocytes fertilized in vitro failed to develop normal pronuclei and cleave within 40-48 h post insemination. We hypothesized t...

Xotx1 is a Xenopus homeobox gene related to the Drosophila gene orthodenticle (otd). We previously reported that Xotx1 transcripts are already present in unfertilized egg. Here we report that maternal Xotx1 mRNA is vegetally localized during oogenesis. In stage II oocytes Xotx1 transcripts are localized within the mitochondrial cloud, in a perinuclear position; later on, they are translocated t...