Search results for " mammalia"
showing 10 items of 126 documents
Potential effects of age-associated oxidative stress on mammalian oocytes/embryos
1996
This bioessay aims to explain the different effects of maternal ageing and postovulatory oocyte ageing on mammalian oocytes/embryos under the scope of 'the oxygen radical-mitochondrial injury hypothesis of ageing'. This hypothesis assumes a key role in the senescent process of oxygen radical damage to mitochondrial DNA, proteins and lipids. It is proposed that a decrease in intracellular ATP concentrations and glutathione (GSH)/glutathione disulphide (GSSG) ratio together with a concomitant increase in cytosolic Ca2+ are major factors causing the observed detrimental effects of ageing on cytoskeletal fibres, fertilization and embryo development.
FISH screening of aneuploidies in preimplantation embryos to improve IVF outcome
2005
Preimplantation genetic diagnosis (PGD) has transformed the approach to the infertility patient in the IVF setting. Although the principal applications of PGD have been to prevent the transmission of sex-linked diseases, in time and with growing knowledge of the chromosomal abnormalities observed in preimplantation embryos, its applications have widened. Nowadays, apart from its implications in the prevention of transmission of chromosomal and genetic abnormalities, PGD is being used with increased frequency to improve the IVF outcome in patients with advanced maternal age (or =38 years of age), recurrent miscarriage (or =2 miscarriages), recurrent IVF failure (or =3 failed IVF attempts) an…
New Tools for Embryo Selection: Comprehensive Chromosome Screening by Array Comparative Genomic Hybridization
2014
The objective of this study was to evaluate the usefulness of comprehensive chromosome screening (CCS) using array comparative genomic hybridization (aCGH). The study included 1420 CCS cycles for recurrent miscarriage (n=203); repetitive implantation failure (n=188); severe male factor (n=116); previous trisomic pregnancy (n=33); and advanced maternal age (n=880). CCS was performed in cycles with fresh oocytes and embryos (n=774); mixed cycles with fresh and vitrified oocytes (n=320); mixed cycles with fresh and vitrified day-2 embryos (n=235); and mixed cycles with fresh and vitrified day-3 embryos (n=91). Day-3 embryo biopsy was performed and analyzed by aCGH followed by day-5 embryo tran…
Effect of sperm glutathione peroxidases 1 and 4 on embryo asymmetry and blastocyst quality in oocyte donation cycles
2005
Objective To prospectively determine the impact of concrete components of the sperm oxidative glutathione stress system in terms of enzymatic activity and mitochondrial RNA (mRNA) expression on embryo quality and reproductive outcome. Human spermatozoa use the glutathione system to inactivate reactive oxygen metabolites, and there is a close correlation between some components of the glutathione system and male fertility. However, very few data are published regarding this system in sperm cells and its effect on fertilization ability and embryo development in human beings. Design An oocyte-donation model, used to homogenize the female factor. Setting University-affiliated private IVF settin…
Day-3 embryo metabolomics in the spent culture media is altered in obese women undergoing in vitro fertilization
2015
Objective To determine whether the global metabolomic profile of the spent culture media (SCM) of day-3 embryos is different in obese and normoweight women undergoing in vitro fertilization (IVF). Design Prospective cohort analysis. Setting IVF clinic. Patient(s) Twenty-eight young, nonsmoking women with normoweight, nonsmoking male partners with mild/normal sperm factors undergoing a first IVF attempt for idiopathic infertility, tubal factor infertility, or failed ovulation induction: obese ovulatory women (n = 12); obese women with polycystic ovary syndrome (PCOS; n=4); normoweight ovulatory women (n = 12). Intervention(s) Fifty μl of SCM collected from two day-3 embryos of each cohort. M…
Timing of cell division in human cleavage-stage embryos is linked with blastocyst formation and quality
2012
Noninvasive markers of embryo quality are being sought to improve IVF success. The present study aimed to discover possible associations between embryo division kinetics in the cleavage stage, the subsequent ability of human embryos to reach the blastocyst stage and the resulting blastocyst morphology. A retrospective cohort study analysed 834 embryos from 165 oocyte donation couples using a time-lapse monitoring system that allowed the recording of the exact timings for key events related to embryo development. Timing parameters were categorized into four quartiles. The probability of an embryo developing to a blastocyst was linked to a strict chronology of development. To further evaluate…
Clinical experience and perinatal outcome of blastocyst transfer after coculture of human embryos with human endometrial epithelial cells: a 5-year f…
2003
Abstract Objective To evaluate the reproductive and neonatal outcome of blastocyst transfer after coculture with human endometrial epithelial cells in IVF and oocyte donation. Design Retrospective study. Setting Private assisted reproductive center. Patient(s) Two hundred sixty women undergoing IVF and 469 oocyte recipients. Intervention(s) IVF or intracytoplasmic sperm injection (ICSI) and transfer of at least one blastocyst after coculture with human endometrial epithelial cells. Main outcome measure(s) Blastocyst formation rate, implantation and pregnancy rates, neonatal outcome, and congenital birth defects. Results Among patients who had transfer with their own oocytes, 1,193 of 2,349 …
Clinical validation of embryo culture and selection by morphokinetic analysis: a randomized, controlled trial of the EmbryoScope.
2014
Objective To determine whether incubation in the integrated EmbryoScope time-lapse monitoring system (TMS) and selection supported by the use of a multivariable morphokinetic model improve reproductive outcomes in comparison with incubation in a standard incubator (SI) embryo culture and selection based exclusively on morphology. Design Prospective, randomized, double-blinded, controlled study. Setting University-affiliated private in vitro fertilization (IVF) clinic. Patient(s) Eight hundred forty-three infertile couples undergoing intracytoplasmic sperm injection (ICSI). Intervention(s) No patient intervention; embryos cultured in SI with development evaluated only by morphology (control …
Improved accuracy of hysteroembryoscopic biopsies for karyotyping early missed abortions
2003
Abstract Objective To assess the potential of direct embryo and chorion biopsies obtained by hysteroembryoscopy for karyotyping early missed abortions. Design Clinical prospective descriptive study. Setting Instituto Valenciano de Infertilidad, Valencia, Spain. Patient(s) Sixty-eight women (71 gestational sacs) with missed abortions. The gestational age on ultrasound was 6.3 weeks (range, 4–10 weeks). Intervention(s) Transcervical hysteroembryoscopy before curettage. Main outcome measure(s) Comparison between the cytogenetic results from hysteroembryoscopic biospies and those of the curettage material. Result(s) Hysteroembryoscopic biopsies could be taken in 97.2% of the gestational sacs. D…
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…