Search results for "Oocytes"
showing 10 items of 132 documents
Oogenesis and reproductive investment of Atlantic herring are functions of not only present but long-ago environmental influences as well
2017
Following general life history theory, immediate reproductive investment (egg mass × fecundity/body mass) in oviparous teleosts is a consequence of both present and past environmental influences. This clarification questions the frequent use of season-independent (general) fecundity formulas in marine fish recruitment studies based on body metrics only. Here we test the underlying assumption of no lag effect on gametogenesis in the planktivorous, determinate-fecundity Atlantic herring (Clupea harengus) displaying large plasticity in egg mass and fecundity, examining Norwegian summer–autumn spawning herring (NASH), North Sea autumn-spawning herring (NSAH), and Norwegian spring-spawning herri…
Magnesium ions promote assembly of channel-like structures from beticolin 0, a non-peptide fungal toxin purified from Cercospora beticola.
1998
Beticolins are toxins produced by the fungus Cercospora beticola. Using beticolin 0 (B0), we have produced a strong and Mg(2+)-dependent increase in the membrane conductance of Arabidopsis protoplasts and Xenopus oocytes. In protein-free artificial bilayers, discrete deflexions of current were observed (12 pS unitary conductance in symmetrical 100 mM KCl) in the presence of B0 (approximately 10 microM) and in the presence of nominal Mg2+. Addition of 50 microM Mg2+ induced a macroscopic current which could be reversed to single channel current by chelating Mg2+ with EDTA. Both unitary and macroscopic currents were ohmic. The increase in conductance of biological membranes triggered by B0 is…
Cytosolic pH regulates root water transport during anoxic stress through gating of aquaporins.
2003
Flooding of soils results in acute oxygen deprivation (anoxia) of plant roots during winter in temperate latitudes, or after irrigation1, and is a major problem for agriculture. One early response of plants to anoxia and other environmental stresses is downregulation of water uptake due to inhibition of the water permeability (hydraulic conductivity) of roots (Lpr)2,3,4,5. Root water uptake is mediated largely by water channel proteins (aquaporins) of the plasma membrane intrinsic protein (PIP) subgroup6,7,8. These aquaporins may mediate stress-induced inhibition of Lpr2,4,9 but the mechanisms involved are unknown. Here we delineate the whole-root and cell bases for inhibition of water upta…
Effect of oocyte morphology on post-warming survival and embryo development in vitrified autologous oocytes.
2019
Abstract Research question Does the presence of dysmorphisms affect post-warming survival and embryo development in vitrified autologous oocytes? Design A retrospective study comparing post-warming survival, fertilization and embryo development between morphologically normal (n = 269) and dysmorphic oocytes (n = 147). Results The survival rate was 81.4% in the morphologically normal oocytes and 87.1% in the dysmorphic oocyte group (OR 1.53; 95% CI 0.86 to 2.72). The fertilization rate was 69.9 versus 66.4% (OR 0.85; 95% CI 0.53 to 1.36), the proportion of good-quality embryos on day 3 was 30.3% versus 32.0% (OR 1.08; 95% CI 0.59 to 1.97) and the blastocyst formation rate was 54.5% versus 60…
Ovarian stimulation for oocyte vitrification does not modify disease-free survival and overall survival rates in patients with early breast cancer
2019
Research question: Does ovarian stimulation for oocyte vitrification affect disease-free survival and overall survival rates in women with early breast cancer? Design: This cohort study included 259 patients with early breast cancer; 148 patients underwent ovarian stimulation, whereas 111 patients did not. Patients were treated between January 2008 and December 2016. To calculate the disease-free survival time and overall survival rate, the time of definitive surgery was defined as the starting point. The follow-up was conducted up to 5 years. Results: Exposed and non-exposed groups were comparable in tumour, node and metastases classification, Nottingham grade, hormonal receptor status, tu…
The carriers of the A/G-G/G allelic combination of the c.2039 A>G and c.-29 G>A FSH receptor polymorphisms retrieve the highest number of oocytes in …
2016
The objective of this study was the elucidation of the possible role of the single-nucleotide polymorphisms (SNP) at position -29 and 2039 of the FSH receptor gene (FSHR) as independent predictive markers of ovarian response. Indeed, the tailoring of reproductive treatments is crucial for both maximizing the success of IVF patients and obtaining a reduction in hypo- or hyper-response rates. This prospective, observational study analyzed the association of -29 and 2039 FSHR polymorphisms with the number of retrieved oocytes in 140 patients attending an IVF/ICSI cycle for severe male factors (≤5,000,000 spermatozoa/mL) or tubal factors at the ANDROS Day Surgery Clinic, Palermo, Italy. The res…
Preimplantation genetic testing for aneuploidy in patients with partial X monosomy using their own oocytes: is this a suitable indication?
2019
Objective To describe the outcome of preimplantation genetic testing (PGT-A) using their own oocytes in patients with mosaic Turner Syndrome (MTS). The impact of the assisted reproduction technique (ART) performed (PGT-A or oocyte donation) and the type of absence of the X chromosome (total or partial) were considered. Design Retrospective observational multicenter study. Setting University-affiliated private in vitro fertilization center. Patient(s) Fifty-six patients with MTS with whom 65 ovarian stimulation cycles for PGT-A (fluorescence in situ hybridization/arrays-next generation sequencing) were performed. The study included 90 women with MTS and 20 women with pure Turner Syndrome (PT…
Number needed to freeze: cumulative live birth rate after fertility preservation in women with endometriosis
2021
Research question: How does the number of oocytes used affect the cumulative live birth rate in endometriosis patients who had their oocytes vitrified for fertility preservation (FP)? Design: Retrospective observational study including data from 485 women with endometriosis who underwent FP from January 2007 to July 2018. Survival curves and Kaplan-Meier plots were used to analyse the cumulative live birth rate (CLBR) according to the number of vitrified oocytes used. Data were stratified according to age, stage of the disease and ovarian surgery prior to FP (operated vs. non-operated). Endometriosis curves were compared to plots developed using elective fertility preservation (EFP) patient…
Gene Expression and Apoptosis Levels in Cumulus Cells of Patients with Polymorphisms of FSHR and LHB Undergoing in Vitro Fertilization Program
2017
Background/Aims: FSH receptor (FSHR) Ala307Thr and Asn680Ser and LHβ chain (LHB) Trp28Arg and Ile35Thr polymorphisms affect the response to pharmacological ovarian stimulation with r-FSH in women undergoing assisted reproductive treatment (ART). Here, we evaluated the expression level of selected genes involved in follicle maturation and the possible onset of apoptosis in cumulus cells of patients with single and double FSHR and LHB polymorphisms, as potential markers of oocyte competence. Methods: Cumulus cells from 36 stimulated patients were collected and SNP genotyping performed by PCR. Gene expression was evaluated through real-time PCR, and apoptosis estimated via TUNEL assay, and cle…
Vitrification of human oocytes.
2018
In recent years, growing evidence for the safety and efficiency of oocyte vitrification has made this technique be increasingly proposed for fertility preservation (FP). The populations who could benefit from FP include oncological patients who need the option to preserve their gametes before undergoing potential sterilizing treatment, patients with non-oncologic conditions requiring gonadotoxic chemotherapy and women who wish to delay their motherhood for a variety of reasons. By vitrifying oocytes, women have the chance to conceive in the future, have their own genetic offspring and maintain their reproductive autonomy. This review focuses on describing current knowledge on oocyte vitrifi…