Search results for "Embryo"

GnRH agonist versus recombinant HCG in an oocyte donation programme: a randomized, prospective, controlled, assessor-blind study.

2009

The use of gonadotrophin-releasing hormone (GnRH) agonists for triggering ovulation remains controversial. The primary objective of this study was to evaluate the incidence of ovarian hyperstimulation syndrome (OHSS) following GnRH agonist versus recombinant human chorionic gonadotrophin (HCG) as methods for triggering ovulation. A second aim was to compare the clinical outcome and embryo quality according to the two procedures. The cycle characteristics of 100 oocyte donors undergoing ovarian stimulation and IVF outcomes of their 100 oocyte recipients were analysed. Donors were prospectively randomized into two groups on the last day of ovarian stimulation: Group I received a single bolus …

Concomitant gonadotropin-releasing hormone agonist and menotropin treatment for the synchronized induction of multiple follicles.

1988

In an effort to overcome possible interference by endogenous gonadotropin-ovarian hormone dynamics, desensitization of the pituitary gonadotropins by a gonadotropin-releasing hormone agonist (GnRHa) was achieved in 12 women with repeatedly failed attempts at multiple follicular stimulation. Eight women were scheduled for in vitro fertilization (IVF) and embryo transfer (ET), and 4 for gamete intrafallopian transfer (GIFT). Stimulation failure was characterized by premature luteinization, poor estradiol (E2) response, or inadequate follicular growth. The agonist was administered by nasal spray 500 to 600 micrograms/day beginning on days 21 to 23 of the menstrual cycle. A rapid desensitizatio…

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.…

Is ovarian stimulation detrimental to the endometrium?

2007

Ovarian stimulation in assisted reproduction technology produces lower implantation rates per embryo transferred than natural and ovum donation cycles, suggesting suboptimal endometrial development due to the abnormal concentrations of hormones used to recruit more oocytes. After the publication of several studies on the gene expression profile of endometrial receptivity in the natural cycle using microarray technology, researchers have investigated the impact of ovarian stimulation on the gene expression pattern of the endometrium. Ovarian stimulation cycles that use gonadotrophin-releasing hormone (GnRH) agonists and antagonists have been analysed in detail during the window of implantati…

Eric Hobsbawm, Äärimmäisyyksien aika (1914–1991) ja Risto Alapuro, Vallankumouksessa. Moskovan päiväkirjat 1990–1991

2022

Note sull'embriologia nella tarda antichità e la prima età bizantina

2019

This paper deals with the outcomes of Galenism in Greek Late Antiquity and in the first period of the Byzantine era, considering particularly the rare but significant elements of novelty which are present in the rereading of the ancient tradition by John of Alexandria, in the Alexandrian Summaries of the Galenic Canon, and by Stephanus and Theophilus Protospatharius.

Towards an ideal source of mesenchymal stem cell isolation for possible therapeutic application in regenerative medicine.

2014

Background. The possibility of obtaining mesenchymal stem cells (MSCs) from fetal tissue such as amniotic fluid, chorionic villi and placenta is well-known and a comparison between MSCs originating in different sources such as fetal tissue and those from bone marrow in terms of yield and function is a topical issue. The mesenchymal stem cells isolated from bone marrow are well-characterized. Unfortunately the low quantitative yield during isolation is a major problem. For this reason, other tissue sources for MSCs are of paramount importance. Conclusion. In this review, starting from a description of the molecular and cellular biology of MSCs, we describe alternative sources of isolation ot…

Übertragung von Verhaltensweisen durch Transplantation von Anlagen neuroanatomischer Strukturen bei Amphibienlarven

2010

By replacing parts of the neural plate (prospective medulla oblongata) of Triturus vulgaris by neural ectoderm of Xenopus laevis larval chimaeras were obtained, which showed donorlike rhythmical movements of distinct parts of the visceral musculature according to the place of implantation. Especially the branchial region with its external gills showed rhythmical movements and is the special object of this investigation.

Inhibition of Histone Deacetylase Activity in Human Endometrial Stromal Cells Promotes Extracellular Matrix Remodelling and Limits Embryo Invasion

2011

Invasion of the trophoblast into the maternal decidua is regulated by both the trophoectoderm and the endometrial stroma, and entails the action of tissue remodeling enzymes. Trophoblast invasion requires the action of metalloproteinases (MMPs) to degrade extracellular matrix (ECM) proteins and in turn, decidual cells express tissue inhibitors of MMPs (TIMPs). The balance between these promoting and restraining factors is a key event for the successful outcome of pregnancy. Gene expression is post-transcriptionally regulated by histone deacetylases (HDACs) that unpacks condensed chromatin activating gene expression. In this study we analyze the effect of histone acetylation on the expressio…

Come un tenero virgulto: termini e ideologie della crescita nel pensiero greco pre-aristotelico

2020

Dopo un inquadramento terminologico atto a presentare le più comuni radici che esprimono in greco antico i concetti di crescita e di sviluppo del vivente, l’attenzione è rivolta alle modalità con cui in testi di varia natura e datazione (da Omero sino al Corpus ippocratico) si descrive la crescita dell’essere umano a partire dal costante confronto con il mondo vegetale, in modo che dal configurarsi delle teorie possano risaltare le più o meno implicite mentalità. Attraverso il massiccio ricorso al ragionamento analogico, le fonti considerate permettono di farsi un’idea non solo del processo di crescita in sé, ma anche del ruolo assegnato nella cultura e nel pensiero della Grecia antica alla…