Search results for "Pronucleus"
showing 9 items of 9 documents
Value of the sperm deoxyribonucleic acid fragmentation level, as measured by the sperm chromatin dispersion test, in the outcome of in vitro fertiliz…
2005
To determine the prognostic value of sperm DNA fragmentation levels, as measured by the sperm chromatin dispersion (SCD) test, in predicting IVF and ICSI outcome.Double-blind prospective study.University-affiliated private IVF setting.A total of 85 couples undergoing infertility treatment with IVF/ICSI.Analysis of DNA fragmentation by the SCD test in 170 aliquots obtained from the ejaculate and from the processed semen used for assisted reproductive technologies (ART).Percentage of spermatozoa with fragmented DNA was statistically correlated with embryo quality and reproductive success.Fertilization rate was inversely correlated with DNA fragmentation (r = -0.245 P = .045). Higher DNA fragm…
Can novel early non-invasive biomarkers of embryo quality be identified with time-lapse imaging to predict live birth?
2019
AbstractSTUDY QUESTIONCan time-lapse imaging systems make it possible to identify novel early non-invasive biomarkers to predict live birth?SUMMARY ANSWERFrom mostly high-grade embryos, out of 35 morphometric, morphologic and morphokinetic variables, only pronuclei (PN) position at time of PN juxtaposition and the absence of multinucleated blastomeres at the 2-cell stage (MNB2cell), were potentially associated with live birth.WHAT IS KNOWN ALREADYPrevious studies indicate that some kinetic markers may be predictive of blastocyst development and embryonic implantation. Certain teams have suggested including some of them in decisional algorithms for embryo transfers.STUDY DESIGN, SIZE, DURATI…
Funktion der Spermien in inkompatiblen Kreuzungen der StechmückeCulex pipiens L.
1972
After irradiating males of the incompatible crossC. pipiens ‘Hamburg’ ♀♀×C. pipiens ‘Paris’ ♂♂ with X-ray doses between 1 kR and 40 kR, it could be shown that in this cross the sperm has only the function of activating the egg. All the hybrid embryos develop from the haploid female pronucleus.
Genetische Untersuchungen zur Inkompatibilität im Culex-pipiens-Komplex
1970
In crosses between populations of the mosquito Culex pipiens of different geographical origin three crossing types have been found (1) crosses with normal offspring (2) crosses with reduced offspring and (3) crosses that show almost total incompatibility. In the case of incompatible crosses 99.9% of the developing embryos are lethal and only about 0.1% of the embryos hatch and develop into fertile diploid females. The origin of the exceptional diploid females has been investigated by means of the marker genes Kuf, r, w, var, y and ru. These females develop from a diploid oocyte or from a diploid nucleus that originated by fusion of the pronucleus and the last polar body. This has been concl…
Dynamic changes of the microtubule system corresponding to the unequal and spiral cleavage modes in the embryo of the zebra mussel, Dreissena polymor…
1998
Unequal cleavage requires a highly organised cytoskeleton. We investigated the localisation of both tubulins and microtubular arrays in Dreissena eggs during and after fertilisation using confocal laser scanning microscopy. Freshly spawned eggs are arrested in metaphase I. A maternal pool of γ-tubulin is found mainly in the centre of the asters of the meiotic spindle. The paternal pool of γ-tubulin, present in the fertilising sperm, could not be traced within the egg, but a microtubule-organising centre forms near the male pronucleus at anaphase II. Male and female pronuclei grow as they migrate in the wake of their aster and rendezvous. First cleavage is unequal and starts without pronucle…
“BEP” RNAs and Proteins Are Situated in the Animal Side of Sea Urchin Unfertilized Egg, Which Can Be Recognized by Female Pronuclear Localization
1996
Microsurgery experiments demonstrate that the animal side of the unfertilized sea urchin Paracentrotus lividus egg coincides with the side of the egg pronucleus location. It is demonstrated by means of in situ hybridization and immunostaining of whole mounts of animal or vegetal halves that the previously identified bep 1 and bep4 RNAs and their proteins are located in the animal part of the unfertilized egg and much less in the vegetal part. The addition of Fabs against BEP1 and BEP4 causes exogastrulation.
Fertilization and early embryology: Morphometric characterization of normal and abnormal human zygotes
1995
Human zygotes (n = 278) from 96 in-vitro fertilization gonadotrophin-stimulated cycles were photographed in their pronuclear stage (16-18 h post-insemination). Normal morphological fertilization (two pronuclei) was observed in 215 zygotes, 17 showed only one pronucleus, 40 showed three pronuclei and six showed four. Area, perimeter and maximum and minimum diameters of each zygote and pronucleus were measured using an IBAS 2000 (Kontron) image analyser. When the four groups were compared, whole zygotes did not show any morphometric difference. However, pronuclei from these groups showed that a high number of pronuclei was directly related to small pronuclei. Differences in pronuclear size an…
Origin and ploidy of multipronuclear zygotes
2000
Recently, several authors have proposed strategies for correction of triploidy based on the removal of the extra pronucleus at the zygote stage. In the present bioassay, the following were analysed: (1) the different factors that can induce the formation of multipronuclear zygotes in mammals; (2) the different morphological patterns established according to the number of pronuclei and polar bodies that can be observed at the zygote stage and used to distinguish the origin of multipronuclear zygotes; and (3) the pattern of chromosomal segregation during the first mitotic division and ploidy status of the resulting preim-plantation embryos. Such an analysis shows that the morphological crite…
The human first cell cycle: impact on implantation.
2013
The morphology of fertilization events has been related to successful implantation by subjective criteria (pronuclei score, pronuclei symmetry and position). This work first described these events by time-lapse technology and then compared the timings of fertilization events (second polar body extrusion, first and second pronuclei appearance, abuttal and fading) in implanted versus nonimplanted embryos in a 2-year cohort retrospective study. A total of 1448 transferred embryos from 842 patients undergoing intracytoplasmic sperm injection with oocyte donation were monitored, 212 embryos from treatments where the number of gestational sacs matched the number of transferred embryos and 687 emb…