Embryonic Development Research Papers - Academia.edu (original) (raw)

Purpose Preimplantation Genetic Diagnosis (PGD) has proven to be a useful reproductive option for carriers of some chromosome rearrangements. The data presented in this study compares the impact of one versus two blastomere biopsy on the... more

Purpose Preimplantation Genetic Diagnosis (PGD) has proven to be a useful reproductive option for carriers of some chromosome rearrangements. The data presented in this study compares the impact of one versus two blastomere biopsy on the likelihood of achieving a PGD result, as well as the effect on subsequent embryo development and clinical outcomes. Methods IVF-PGD couples had either one or two blastomeres biopsied from all embryos with ≥7 blastomeres on day 3 post oocyte collection. These blastomeres were assessed for the specific chromosome rearrangement using Fluorescent In-situ Hybridisation (FISH). Further embryo development was monitored on days 4 and 5. Clinical outcomes were assessed retrospectively. Results The data shows that statistically more embryos achieved a PGD result following two blastomere biopsy, compared with one blastomere biopsy (92 % versus 88 %, respectively). Furthermore it was found that embryo development and clinical outcomes were similar between the two biopsy groups. Conclusions Based on this analysis it appears that the biopsy of two blastomeres from embryos with ≥7 blastomeres on day 3 is a valid and successful approach for couples presenting for IVF-PGD for a chromosome rearrangement.

The evolution of viviparity requires modifications to multiple integrated physiological features to support embryonic development during pregnancy. Embryonic growth during pregnancy is dependent upon the capacity of the uterine vascular... more

The evolution of viviparity requires modifications to multiple integrated physiological features to support embryonic development during pregnancy. Embryonic growth during pregnancy is dependent upon the capacity of the uterine vascular system to satisfy increasing embryonic oxygen demand throughout gestation. We tested the hypothesis that total surface area of uterine blood vessels increases in concert with embryonic growth, and hence its oxygen demand, during gestation. We used immunofluorescence and laser-scanning confocal microscopy to quantify uterine microvascular density and morphology during gestation in the oviparous skink Ctenotus taeniolatus and in Saiphos equalis, a skink species with prolonged egg retention. For C. taeniolatus, vessel density (Nv) and vessel length-density (Lv) in the embryonic hemisphere of the uterus is 23% and 17% less, respectively, than that of S. equalis and vascular surface-area does not differ as a function of embryo stage. For S. equalis, overall Nv, Lv, and vessel diameter (Dv), does not change during the first half of gestation but increases by 36% (Nv), 44% (Lv), and 60% (Dv) by near-term embryo stages late in gestation. The chorioallantoic membrane of S. equalis increases in absolute size but vascular density does not differ as a function of embryo stage. The marked increase in uterine vascular density during late gestation coincides with the phase of rapid growth in embryo mass and concomitant increase in metabolic rate. Expansion of the uterine vascular bed in concert with embryo size and metabolism is likely to be an important transitional step in the evolution of viviparity. Anat Rec, 293:829–838, 2010. © 2010 Wiley-Liss, Inc.

Porcine handmade cloning (HMC), a simplified alternative of micromanipulation based traditional cloning (TC) has been developed in multiple phases during the past years, but the final evidence of its biological value, births of piglets... more

Porcine handmade cloning (HMC), a simplified alternative of micromanipulation based traditional cloning (TC) has been developed in multiple phases during the past years, but the final evidence of its biological value, births of piglets was missing. Here we report the first births of ...

Development of the nervous system begins with neural induction, which is controlled by complex signaling networks functioning in concert with one another. Fine-tuning of the bone morphogenetic protein (BMP) pathway is essential for neural... more

Development of the nervous system begins with neural induction, which is controlled by complex signaling networks functioning in concert with one another. Fine-tuning of the bone morphogenetic protein (BMP) pathway is essential for neural induction in the developing embryo. However, the molecular mechanisms by which cells integrate the signaling pathways that contribute to neural induction have remained unclear. We find that neural induction is dependent on the Ca(2+)-activated phosphatase calcineurin (CaN). Fibroblast growth factor (FGF)-regulated Ca(2+) entry activates CaN, which directly and specifically dephosphorylates BMP-regulated Smad1/5 proteins. Genetic and biochemical analyses revealed that CaN adjusts the strength and transcriptional output of BMP signaling and that a reduction of CaN activity leads to an increase of Smad1/5-regulated transcription. As a result, FGF-activated CaN signaling opposes BMP signaling during gastrulation, thereby promoting neural induction and ...

The neural crest is a transient, multipotent embryonic cell population in vertebrates giving rise to diverse cell types in adults via intermediate progenitors. The in vivo cell-fate potential and lineage segregation of these postembryonic... more

The neural crest is a transient, multipotent embryonic cell population in vertebrates giving rise to diverse cell types in adults via intermediate progenitors. The in vivo cell-fate potential and lineage segregation of these postembryonic progenitors is poorly understood, and it is unknown if and when the progenitors become fate restricted. We investigate the fate restriction in the neural crest-derived stem cells and intermediate progenitors in zebrafish, which give rise to three distinct adult pigment cell types: melanophores, iridophores, and xanthophores. By inducing clones in sox10-expressing cells, we trace and quantitatively compare the pigment cell progenitors at four stages, from embryogenesis to metamorphosis. At all stages, a large fraction of the progenitors are multipotent. These multipotent progenitors have a high proliferation ability, which diminishes with fate restriction. We suggest that multipotency of the nerve-associated progenitors lasting into metamorphosis ma...

To analyze whether a change in three-dimensional structure of the zona pellucida could indicate suboptimal gamete quality. Prospective study. Women's general hospital. A total of 72 patients who... more

To analyze whether a change in three-dimensional structure of the zona pellucida could indicate suboptimal gamete quality. Prospective study. Women's general hospital. A total of 72 patients who gave informed consent. The birefringence of all oocytes was prospectively analyzed with an automatic user-independent polarization microscopy imaging system. Birefringence of the inner zona layer, preimplantation development, implantation, and pregnancy. In approximately one third of all gametes (244/712), the system's automatic detection of the inner zona layer did not succeed. This phenomenon was a negative predictor of compaction (P<0.01), blastulation (P<0.001), and pregnancy (P<0.001). In cases of successful zona imaging, the score based on the birefringence of the inner zona layer was a strong predictor of blastocyst formation but not of embryo quality or pregnancy (P>0.05). Interestingly, antagonist protocol resulted in lower zona scores as compared with the long protocol (P<0.05). Combining the information from both undetected and detected oocytes, zona imaging was a helpful tool in oocyte selection. This knowledge might further help to reduce both the time in culture and the number of concepti considered for transfer.

The Drosophila pair-rule gene odz (Tenm) has many patterning roles throughout development. We have identified four mammalian homologs of this gene, including one previously described as a mouse ER stress response gene, Doc4 (Wang et al.,... more

The Drosophila pair-rule gene odz (Tenm) has many patterning roles throughout development. We have identified four mammalian homologs of this gene, including one previously described as a mouse ER stress response gene, Doc4 (Wang et al., 1998). The Odz genes encode large polypeptides displaying the hallmarks of Drosophila Odz: a putative signal peptide; eight EGF-like repeats; and a putative transmembrane domain followed by a 1800-amino-acid stretch without homology to any proteins outside of this family. The mouse genes Odz3 and Doc4/Odz4 exhibit partially overlapping, but clearly distinct, embryonic expression patterns. The major embryonic sites of expression are in the nervous system, including the tectum, optic recess, optic stalk, and developing eye. Additional sites of expression include trachea and mesodermally derived tissues, such as mesentery, and forming limb and bone. Expression of the Odz2 gene is restricted to the nervous system. The expression patterns suggest that each of the genes has its own distinct developmental role. Comparisons of Drosophila and vertebrate Odz expression patterns suggest evolutionarily conserved functions.

The signaling component of the mammalian Fibroblast Growth Factor (FGF) family is comprised of eighteen secreted proteins that interact with four signaling tyrosine kinase FGF receptors (FGFRs). Interaction of FGF ligands with their... more

The signaling component of the mammalian Fibroblast Growth Factor (FGF) family is comprised of eighteen secreted proteins that interact with four signaling tyrosine kinase FGF receptors (FGFRs). Interaction of FGF ligands with their signaling receptors is regulated by protein or proteoglycan cofactors and by extracellular binding proteins. Activated FGFRs phosphorylate specific tyrosine residues that mediate interaction with cytosolic adaptor proteins and the RAS-MAPK, PI3K-AKT, PLCγ, and STAT intracellular signaling pathways. Four structurally related intracellular non-signaling FGFs interact with and regulate the family of voltage gated sodium channels. Members of the FGF family function in the earliest stages of embryonic development and during organogenesis to maintain progenitor cells and mediate their growth, differentiation, survival, and patterning. FGFs also have roles in adult tissues where they mediate metabolic functions, tissue repair, and regeneration, often by reactiv...

ReProTect is a project within the 6th European Framework Program which has developed alternative methods aimed to reduce or replace animal experimentation in the field of reproductive toxicology. In its final year, a ring trial, named the... more

ReProTect is a project within the 6th European Framework Program which has developed alternative methods aimed to reduce or replace animal experimentation in the field of reproductive toxicology. In its final year, a ring trial, named the “Feasibility Study”, was conducted, in which 10 blinded chemicals with toxicologically well-documented profiles were analyzed by employing a test battery of 14 in vitro assays. EC50 (half maximal effective concentration) or equivalent endpoints were determined and the test compounds were ranked relative to chemicals previously assayed in the tests of the battery. This comparative analysis together with a weight of evidence approach allowed a robust prediction of adverse effects on fertility and embryonic development of the 10 test chemicals in vivo. In summary, the vast majority of the predictions made based on the in vitro results turned out to be correct when compared to the whole animal data. The procedure used here, a nearest neighbor analysis coupled with a weight of evidence approach, may guide future activities in the field of alternative toxicity testing.