Search results for "Embryonic Structures"
showing 10 items of 623 documents
Foetal erythrocytes exhibit an increased ability to scavenge for nitric oxide
1998
The presence of adult human whole blood inhibited in vitro relaxations of rat aortic rings by the nitric oxide (NO) donor S-nitroso-N-acetyl-DL-penicillamine (SNAP). Incubation with foetal blood containing the same concentration of haemoglobin produced a shift to the right of the relaxation curve. SNAP-induced vasorelaxations were more inhibited by dialysed solutions of haemoglobin than by the presence of erythrocytes in the organ bath, but there were no differences between the effect of adult or foetal haemoglobins. The presence of plasma from adult or foetal blood did not modify the effects of SNAP. Relaxations induced by endogenous, endothelium-derived, NO were more inhibited by foetal t…
Expression of aquaporins early in human pregnancy
2011
Abstract Background Aquaporins (AQPs) constitute a family of channel proteins implicated in transmembrane water transport. Thirteen different AQPs (AQP0–12) have been described but their precise biologic function still remains unclear. AQPs 1, 3, 4, 8, and 9 expression has been described in human chorion, amnion and placenta; however, AQP4 is the only that has been identified in the first trimester of human pregnancy. Objective To assess multiplicity of AQPs expression from 10th to 14th week gestation. Population and methods Chorionic villi samples (CVS) collected in pregnant women for prenatal diagnosis were analysed by real time-PCR to assess cDNA expression of AQPs 1, 2, 3, 4, 5, 6, 7, 8…
Impact of chromosomal abnormalities on preimplantation embryo development.
2007
Objectives To evaluate the influence of numerical chromosomal abnormalities on preimplantation embryo development. Methods This study includes 6936 embryos from 1245 women undergoing preimplantation genetic diagnosis (PGD). Indications for aneuploidy screening were: recurrent miscarriages, implantation failure, severe male factor, advanced maternal age, and mixed causes. Embryo biopsy was performed on day 3, and embryos were co-cultured until day 5, when embryo transfer was performed. Results In the aneuploidy screening regimen, normal euploid embryos showed significantly higher blastocyst rates (68.2%) compared to chromosomally abnormal (42.8%, p < 0.0001) and mosaic (53.7%, p < 0.0001) em…
Vitrification of preimplantation genetically diagnosed human blastocysts and its contribution to the cumulative ongoing pregnancy rate per cycle by u…
2008
Objective To evaluate the survival rate and clinical results of our vitrification procedure on preimplantation genetic diagnosis (PGD) blastocysts and to calculate its actual contribution to the reproductive outcome per cycle. Design Retrospective clinical study. Setting University Institute IVI, Valencia, Spain. Patient(s) Patients who requested cryotransfer of surplus PGD blastocysts after failed fresh elective transfer. Intervention(s) Retrospectively collected data during 2 years of experience with blastocyst vitrification. Main Outcome Measure(s) Primary outcome measures were the following: blastocyst recovery and survival; cryotransfer cancellation; and the implantation, pregnancy (PR…
Assessment of the implantation of day-2 human embryos by morphometric nonsubjective parameters
2014
Objective: To demonstrate the usefulness of image analysis in designing objective embryonic morphometric variables. Design: Retrospective study of 214 top-quality day-2 embryo photographs from 50 double-embryo transfers resulting in no pregnancy (group 0) and 57 resulting in twin pregnancy (group 1). Setting: Human reproduction unit. Patient(s): Study of 107 in vitro fertilization intracytoplasmic sperm injection (IVF ICSI) cycles in women age<36 years with doubleembryo transfer of top-quality embryos. Only the first cycle of IVF ICSI was included. Intervention(s): Standard IVF ICSI protocols. Main Outcome Measure(s): The embryo photographs were analyzed using the ImageJ program. The effect…
Limited implantation success of direct-cleaved human zygotes: a time-lapse study.
2012
Objective To evaluate embryos with direct cleavage (≤5 hours) from two to three cells (DC2–3) and correlate this morphokinetic parameter to implantation and ongoing pregnancy. Design Clinical multicenter retrospective study. Setting Private in vitro fertilization (IVF) centers. Patient(s) From three clinics, a total of 979 treatments including 5,225 embryos using autologous or donated oocytes, of which 1,659 embryos were transferred. Intervention(s) None. Main Outcome Measure(s) Clinical pregnancy confirmed by ultrasound in week 7. Result(s) Of the total embryo cohort, 715 (13.7%) underwent direct cleavage from two to three cells, 1,659 embryos were transferred to recipients, and 109 of the…
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…
Antral follicle count (AFC) can be used in the prediction of ovarian response but cannot predict the oocyte/embryo quality or the in vitro fertilizat…
2007
To verify whether the antral follicle count (AFC) could predict ovarian response, oocyte/embryo quality, and IVF outcome.Prospective study.Instituto Universitario-Instituto Valenciano de Infertilidad, Valencia, Spain.One thousand seventy-four donors and 975 oocyte recipient cycles.Controlled ovarian hyperstimulation (COH), endometrial preparation, IVF/intracytoplasmic sperm injection, ET.COH and oocyte/embryo quality parameters and IVF outcome.We observed lower E(2) levels and fewer mature retrieved oocyte numbers among donors who showed an AFC that was10. These donors also showed significantly higher cancellation and no-donation rates; poor and/or insufficient response was the principal ca…
Physiological changes in glutathione metabolism in foetal and newborn rat liver
1991
Glutathione metabolism was studied in isolated hepatocytes from foetal, newborn and adult rats. The GSH/GSSG ratio decreased 15-20-fold through the foetal-neonatal-adult transition. This was mainly due to an increase in GSSG. All enzyme activities involved in the glutathione redox cycle tend to increase during that transition, but the relative increases in glutathione peroxidase and glutathione S-transferase were 3-5 times those of glutathione reductase or glucose-6-phosphate dehydrogenase. GSH synthesis from methionine as a sulphur source was 6 times lower in foetal than in adult hepatocytes. However, when N-acetylcysteine was used as a sulphur donor to by-pass the cystathionine pathway, t…
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.…