Results 261 to 270 of about 79,883 (298)

Oocyte activation in invertebrates and humans

Zygote, 1994
Oocytes are metabolically repressed cells that, in most cases, require a signal from the fertilising spermatozoon to trigger activation. Physiological competence of the activated oocyte, a prerequisite for early embryogenesis, depends, therefore, not only on the quality of the oocyte, but also on the quality of the spermatozoon (Dale, 1983; Tosti &
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Activation of cumulus‐free mouse oocytes

Molecular Reproduction and Development, 1990
AbstractAttempts were made to activate parthenogenetically oocytes from randombred mice under conditions required for nuclear transfer, viz. in the absence of cumulus cells. Of the large number of stimulants previously described and presumed to be generally effective, only exposure to strontium ion (as a replacement for calcium ion in the medium), or ...
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Parthenogenetic activation of human oocytes by puromycin

Journal of Assisted Reproduction and Genetics, 1992
Our objective was to obtain parthenogenetic activation of unfertilized human oocytes by puromycin and to try to use this procedure for cytogenetic purposes.The setting was our IVF laboratory.Eighty-two spare oocytes from 34 IVF patients were used. In the first series of experiments 39 unfertilized oocytes were cultured in medium containing 100, 50, or ...
P, De Sutter, D, Dozortsev, J, Cieslak, G, Wolf, Y, Verlinsky, A, Dyban   +5 more
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Activation of Oocytes After Nuclear Transfer

2006
After nuclear transfer, the recipient oocyte must be stimulated to initiate development. This stimulation is achieved by inducing changes in the oocyte cytoplasm that normally are triggered by the sperm during fertilization. In most cases, such changes include a transient increase in the intracellular-free calcium concentration induced by an electrical
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Oocyte Spontaneous Activation in Different Rat Strains

Cloning and Stem Cells, 2006
Oocyte spontaneous activation (OSA) has been reported to occur during in vitro culture of ovulated rat oocytes. The objective of this study was to compare the rate of oocyte spontaneous activation and the level of maturation promoting factor (MPF) activity in oocytes from different strains.
P J, Ross, A, Yabuuchi, J B, Cibelli
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RNase A activity in Japanese quail oocytes

Zygote, 1996
SummaryThe presence of RNase A activity was studiedin vitroin homogenates of quail oocytes and early embryos using [3H]poly(U) as a substrate. The activity was measured by adsorption of the undegraded substrate onto DE-81 filter paper discs and by chromatographic separation on a Sephadex G-50 column.
U, Stepińska, A, Malewska, B, Olszańska   +2 more
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Use of strontium for bovine oocyte activation

Theriogenology, 2005
Strontium efficiently activates mouse oocytes, however, there is limited information on its use in cattle. Thus, the objective of this study was to establish a suitable protocol for activating bovine oocyte with strontium. For pronuclear development, the absence of calcium and magnesium in the activation medium (TALP) with 10 and 50 mM strontium (34.4 ...
Méo, Simone Cristina, Yamazaki, Walt, Leal, Cláudia Lima Verde, Oliveira, João Ademir de, Garcia, Joaquim Mansano   +4 more
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Oocytes Survival Requires Metabolic Activity

Science's STKE, 2005
Vertebrate females produce their full complement of oocytes during embryogenesis and, over time, these are either released (and fertilized or not) or undergo cell death. Oocyte death ultimately leads to sterility as the animals age and conditions that accelerate death of the eggs cause premature infertility. Nutt et al.
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Lactate dehydrogenase activity in oocytes

Experimental Cell Research, 1967
R G, Kessel, E G, Ellgaard
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Dynamics of egg (oocyte) activation

2009
Fluctuations in the intracellular calcium concentration ([Ca+2i]) are a prerequisite for egg activation. The initial increase in [Ca+2i]is mainly due to Ca2+ release from the ER into the cytoplasm. The Ca2+ wave begins at the site of sperm–egg fusion, and this signal is then propagated throughout the cytoplasm.
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