Background: The cause of fertilization failure in IVF is most often due to the absence of sperm penetration but the reason why fertilization does not occur when intracytoplasmic sperm injection (ICSI) is applied is not clear. However some intrinsic oocyte problems may also be responsible for fertilization failure. It has been reported that 13% of unfertilized oocytes after IVF show morphologica...

Holes or tears have been made in the surface of unfertilized Xenopus eggs or oocytes in various buffered media and the surface response to the wound has been observed with the light microscope. In the presence of calcium ion in the medium, a pigmented ring appears around the wound and constricts in purse-string fashion until the hole is closed. A highly pigmented scar remains. We show that the ...

BACKGROUND Current outcome results with embryos derived from thawed MII human oocyes are significantly lower than with embryos cryopreserved at the pronuclear stage. Here, we investigated whether freezing-thawing was associated with changes in oocyte mitochondrial polarity (DeltaPsim) that could influence competence by altering ATP levels or the ability of the cytoplasm to regulate intracellula...

We have used in situ hybridization and cell fractionation methods to follow the distribution of U1 RNA and immunofluorescence microscopy to follow the distribution of snRNP proteins in oocytes, eggs, and embryos of several sea urchin species. U1 RNA and U1-specific snRNP antigens are concentrated in germinal vesicles of oocytes. Both appear to relocate after oocyte maturation because they are f...

The amounts of the various forms of DNA polymerase (alpha 1, alpha 2, beta, and gamma) have been determined in oocytes, eggs, and embryos of the frog, Xenopus laevis. During oogenesis the relative proportions and absolute levels of all forms changed dramatically. In stage I (early) oocytes, DNA polymerase-gamma, the "mitochondrial" polymerase, was the predominant form. During oocyte growth, DNA...

Within minutes of fertilization of clam oocytes, translation of a set of maternal mRNAs is activated. One of the most abundant of these stored mRNAs encodes the small subunit of ribonucleotide reductase (Standart, N. M., S. J. Bray, E. L. George, T. Hunt, and J. V. Ruderman, 1985, J. Cell Biol., 100:1968-1976). Unfertilized oocytes do not contain any ribonucleotide reductase activity; such acti...

The present study was aimed to facilitate karyotyping of human blastomeres using the metaphase-inducing factors present in unfertilized eggs. A rapid technique for karyotyping would have wide application in the field of preimplantation genetic diagnosis. When cryopreserved in-vitro matured bovine oocytes were fused with human blastomeres, the transferred human nuclei were forced into metaphase ...

BACKGROUND The complex relationship between oocyte morphology, specific follicular fluid metabolites, gene expression in cumulus granulosa cells, and oocyte competence toward fertilization and embryo development still needs further clarification. METHODS Forty-six oocytes retrieved from the largest pre-ovulatory follicle of patients undergoing intra-cytoplasmic sperm injection (ICSI) were con...

Case A 28 year old unmarried woman underwent a unilateral salpingo-oophorectomy and was suspected of having a malignant tumor in the remaining ovary. After consultation with the patient and her family, it was decided to cryopreserve the unfertilized oocytes. In order to reduce the risk of puncturing or rupturing the tumor when performing the oocyte retrieval from the ovary that was affected by ...