نتایج جستجو برای: oocyte activation
تعداد نتایج: 440911 فیلتر نتایج به سال:
We report the successful outcome of intracytoplasmic sperm injection (ICSI) treatment in two siblings with familial globozoospermia. After controlled ovarian hyperstimulation and oocyte pick-up, retrieved oocytes were mechanically activated before ICSI and a fertilization rate of 33.3% was achieved in the first case. The second couple underwent ICSI without oocyte activation and a 9.1% fertiliz...
Recent progress in cell micromanipulation has made it possible to achieve fertilization even with highly deficient male gametes, by injecting them directly to oocyte cytoplasm. This technique, known as intracytoplasmic sperm injection (ICSI), has proved efficient in most types of sperm pathology. However, ICSI fails when injected spermatozoa are not capable of supporting the process of oocyte a...
Pluripotent stem cells are possibly the best candidates for regenerative medicine, and somatic cell nuclear transfer (SCNT) is one of the viable options to make patient-specific embryonic stem cells. Till date efficacy of SCNT embryos is very low and requires further improvement like ideal oocyte activation and in vitro culture system. The aim of the present study was to evaluate ideal oocyte a...
The influence of oocyte age and presence of oocyte meiotic apparatus on the behaviour of introduced blastomere nuclei was evaluated. Blastomeres from 4-cell mouse embryos were fused to intact (metaphase II) oocytes, demi-oocytes (nucleate) or cytoplast (anucleate). Fusion and simultaneous activation of the recipient oocytes were accomplished by a single electrical pulse at 20 or 24 h post human...
A study was made of the electrical and morphological changes in the sea-urchin oocyte during interaction with spermatozoa. The first event, a small step depolarization accompanied by a 20-40% decay in input resistance occurs within seconds of attachment. The evidence suggests that this electrical event is the result of sperm-oocyte fusion, and that the ion channels that lower the resistance acr...
The Drosophila body axes are established in the oocyte during oogenesis. Oocyte polarization is initiated by Gurken, which signals from the germline through the epidermal growth factor receptor (Egfr) to the posterior follicle cells (PFCs). In response the PFCs generate an unidentified polarizing signal that regulates oocyte polarity. We have identified a loss-of-function mutation of flapwing, ...
Mammalian oocyte maturation depends on the translational activation of stored maternal mRNAs upon meiotic resumption. Cytoplasmic polyadenylation element binding protein 1 (CPEB1) is a key oocyte factor that regulates maternal mRNA translation. However, the signal that triggers CPEB1 activation at the onset of mammalian oocyte maturation is not known. We provide evidence that a mitogen-activate...
Translational regulation of localized mRNAs is essential for patterning and axes determination in many organisms. In the Drosophila ovary, the germline-specific Orb protein mediates the translational activation of a variety of mRNAs localized in the oocyte. One of the Orb target mRNAs is orb itself, and this autoregulatory activity ensures that Orb proteins specifically accumulate in the develo...
In mouse somatic cell nuclear transfer (SCNT), polyvinylpyrrolidone (PVP) is typically included in the nuclear donor injection medium. However, the cytotoxicity of PVP, which is injected into the cytoplasm of oocytes, has recently become a cause of concern. In the present study, we determined whether bovine serum albumin deionized with an ion-exchange resin treatment (d-BSA) was applicable to t...
Ca(2+) is the universal signal for egg activation at fertilization in all sexually reproducing species. The Ca(2+) signal at fertilization is necessary for egg activation and exhibits specialized spatial and temporal dynamics. Eggs acquire the ability to produce the fertilization-specific Ca(2+) signal during oocyte maturation. However, the mechanisms regulating Ca(2+) signaling differentiation...
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