Search results for "Blastocyst"

Collapse of blastocysts is strongly related to lower implantation success: a time-lapse study.

2015

Study question Is there an association between blastocyst collapse patterns and implantation potential? Summary answer Embryos that exhibit collapse are as likely to hatch as those that do not, but are less likely to implant and should not be replaced if alternatives are available. What is known already Studies of blastocyst collapse in different species of mammals have found that most blastocysts, that experience consecutive weak contractions, hatch successfully whereas those that exhibit strong contractions or collapse, fail to hatch. Study design, size, duration Retrospective cohort study. Seven hundred and fifteen transferred blastocysts were analyzed from July 2012 to May 2013. Partici…

The role of gonadotropin-releasing hormone in murine preimplantation embryonic development.

1999

Previous studies have established the presence of an extrahypothalamic GnRH in a variety of tissues. GnRH receptor is known to be present in the placenta, which produces and secretes the decapeptide from the very early stages of placentation. We hypothesized that GnRH may play a role in the preimplantation development of embryos. To examine this hypothesis, we assessed GnRH and GnRH receptor messenger RNA (mRNA; RT-PCR) and protein expression (Immunohistochemistry) in preimplantation murine embryos at various developmental stages. Furthermore, preimplantation murine embryos were cultured with GnRH agonist and antagonist in vitro to assess the influence of GnRH analogs on embryo development.…

In vitro fertilization with personalized blastocyst transfer versus frozen or fresh blastocyst transfer: a multicenter, randomized clinical trial

2019

Mitochondrial DNA content decreases during in vitro human embryo development: insights into mitochondrial DNA variation in preimplantation embryos do…

2020

Objective To assess the mitochondrial DNA (mtDNA) load and variation in human oocytes and during preimplantation embryo development using specimens donated for research. Design Prospective cohort study. Setting Not applicable. Patients A total of 50 in vitro fertilization patients and 11 oocyte donors whose specimens were obtained between July 2017 and July 2018. Interventions None. Main Outcome Measures All specimens were separately collected. Quantitative polymerase chain reaction was performed with SurePlex DNA Amplification System (Illumina). Primers for the adenosine triphosphate 8 mitochondrial gene and the β-actin were used. Data were statistically analyzed by analysis of variance wi…

Endometrial Receptivity in Natural and Controlled Ovarian-Stimulated Cycles

2011

The development of endometrial receptivity is a prerequisite for successful embryonic implantation in mammals. The receptive status is reached only during a short period of time in the midluteal phase, this being maximal 7 days after the endogenous peak of LH (LH+7), named as the window of implantation (WOI). At this time, the endometrial epithelium acquires the functional ability to support blastocyst adhesion. In ART, controlled ovarian stimulation (COS) induces lower implantation rates per embryo transferred than natural or ovum donation cycles, suggesting suboptimal endometrial development due to the abnormal endocrine/paracrine milieu. Researchers have investigated the functional genom…

Have Day 3 Embryo Morphology a Predictive Value in Blastocyst Formation?

2000

Reproductive Biology Including Evidence for Superfetation in the European Badger Meles meles (Carnivora: Mustelidae)

2015

The reproductive biology of the European badger (Meles meles) is of wide interest because it is one of the few mammal species that show delayed implantation and one of only five which are suggested to show superfetation as a reproductive strategy. This study aimed to describe the reproductive biology of female Irish badgers with a view to increasing our understanding of the process of delayed implantation and superfetation. We carried out a detailed histological examination of the reproductive tract of 264 female badgers taken from sites across 20 of the 26 counties in the Republic of Ireland. The key results show evidence of multiple blastocysts at different stages of development present s…

Cleavage of endometrial α-integrins into their functional forms is mediated by proprotein convertase 5/6.

2012

Background Proprotein convertases (PCs) post-translationally activate a large number of protein precursors through limited cleavage. PC5/6 (PC6) in the human endometrium is tightly regulated during receptivity for embryo implantation. Integrins are transmembrane glycoproteins, some of which play an important role in the adhesive interactions between the trophoblast (blastocyst) and uterine epithelium at implantation. Integrins require PC cleavage for post-translational modification. We hypothesize that pro-integrin-αs in the endometrial epithelium are post-translationally cleaved by PC6 into functional subunits for the binding of blastocyst and adhesion of extracellular matrix proteins. Met…

Functional Genomics of 5-to 8-Cell Stage Human Embryos by Blastomere Single-Cell cDNA Analysis

2010

Blastomere fate and embryonic genome activation (EGA) during human embryonic development are unsolved areas of high scientific and clinical interest. Forty-nine blastomeres from 5- to 8-cell human embryos have been investigated following an efficient single-cell cDNA amplification protocol to provide a template for high-density microarray analysis. The previously described markers, characteristic of Inner Cell Mass (ICM) (n = 120), stemness (n = 190) and Trophectoderm (TE) (n = 45), were analyzed, and a housekeeping pattern of 46 genes was established. All the human blastomeres from the 5- to 8-cell stage embryo displayed a common gene expression pattern corresponding to ICM markers (e.g., …

The dynamics of structural modifications of mitochondria at the early stages of sea urchin embryonic development

1992

The organization of the chondriome and the ultrastructure of mitochondria have been studied in eggs and embryos of the sea urchin Paracentrotus lividus. The egg chondriome is characterized by an arrangement in well-delimited clusters. Analysis of mitochondrial clusters on electron micrographs of ultrathin serial sections shows two kinds of mitochondria of different shapes, the rod-shaped and the spherical. The egg mitochondria have a dense matrix and a well-ordered arrangement of cristae which, in rod-shaped variety, are perpendicular to the major axis. Cell division is accompanied by significant changes in intracellular distribution of mitochondria and in their structure. At the stage of 2…