Search results for "gamete"
showing 10 items of 24 documents
Effects of tributyltin(IV) chloride on the gametes and fertilization ofAscidia malaca (Ascidiacea: Tunicata)
2003
Ascidia malaca gametes before fertilization incubated in 10-5 or 10-7 M solutions of tributyltin(IV) chloride, TBTCl, for 3 h appear highly damaged under transmission electron microscopy observation. Also, the fertilization process is affected by the compound: the damaged spermatozoa are present in the vitelline coat and the egg does not cleave. An increase of microbodies, structurally similar to peroxisomes, have been detected in the egg peripheral cytoplasm, probably in relation to their role in alleviating damage to some cellular components. The results have shown that the reproduction of ascidians under unfavourable environmental conditions is prevented. Copyright © 2003 John Wiley &…
Cui prodest servāre? Due ipotesi di destinazione per gli embrioni crioconservati
2022
The essay analyses the general ban for the donation of embryos placed into cryopreservation, stated by the Italian legislation n. 40/2004. Such a prevision causes a sine die conservation not only for embryos suitable for implantation, but also for those affected by genetic defects or diseases. The essay points out that donating both types of embryos, respectively, to adoption or to scientific fertility research preserves the dignity of the cells in storage, as a will supported by the consent of both gametes’ providers to the ultimate scope of solidarity.
Assisted reproductive technology results: Why are live-birth percentages so low?
2014
The present bioessay aims to analyze the impact of parental age, cause of infertility, embryo chromosomal anomalies, assisted reproduction technology (ART) treatments, and environmental and occupational exposures to xenobiotics on ART results, particularly on live-birth percentages per transfer. Special attention is paid to analyzing the effects of these factors on the mitochondrial, genetic, and epigenetic traits of gametes and embryos to ascertain the molecular/cellular mechanisms responsible for the relatively low percentages of live births reported year after year in ART cycles. The bias of age distribution of women attending fertility clinics toward the late thirties and beyond and the…
Successful gamete intrafallopian transfer following failed artificial insemination by donor: evidence for a defect in gamete transport?
1988
Gamete intrafallopian transfer (GIFT) was offered as an alternative treatment to 48 women who failed to conceive after artificial insemination with donor semen (AID) in numerous attempts (9 to 24 cycles). The evaluation of these women showed no major cause of infertility as evidenced by normal endocrine, cervical, uterine, and tubal factor studies. Their partners were either azoospermic or severely oligoasthenospermic. During the GIFT cycle, follicular development was induced with (1) clomiphene citrate (days 3 to 7) plus human menopausal gonadotropins (hMG) from day 6 on or (2) human follicle-stimulating hormone (days 3 to 4) plus hMG (day 5 on), until ultrasound revealed 2 follicles 16 mm…
In Vitro-Differentiated Embryonic Stem Cells Give Rise to Male Gametes that Can Generate Offspring Mice
2006
SummaryMale gametes originate from a small population of spermatogonial stem cells (SSCs). These cells are believed to divide infinitely and to support spermatogenesis throughout life in the male. Here, we developed a strategy for the establishment of SSC lines from embryonic stem (ES) cells. These cells are able to undergo meiosis, are able to generate haploid male gametes in vitro, and are functional, as shown by fertilization after intracytoplasmic injection into mouse oocytes. Resulting two-cell embryos were transferred into oviducts, and live mice were born. Six of seven animals developed to adult mice. This is a clear indication that male gametes derived in vitro from ES cells by this…
Gamete intrafallopian transfer in the treatment of infertility: the first series at the University of Palermo
1986
Twenty-six couples with unexplained infertility (UI), nine women with repeated failures of artificial insemination with donor semen (AID), three women with mild endometriosis, three with periadnexal adhesions, one with hostile (not immunologic) cervical mucus, and one couple in which the male partner was affected by asthenospermia were treated by the gamete intrafallopian transfer (GIFT) technique. Three different protocols for controlled ovarian hyperstimulation were used, and an adequate follicular growth and oocyte maturation were achieved in all cases. Seventeen pregnancies were obtained, for a global pregnancy rate of 38.6%. Two pregnancies (11.7%) ended in clinical abortions, and one …
Consequences on offspring of abnormal function in ageing gametes.
2000
The present review aims to analyse (i) the molecular, biochemical and cellular changes that accompany oocyte and sperm ageing in any of the internal or external environments where they can reside, and (ii) the consequences of the abnormal function in ageing gametes on pre- and post-implantation development and later life of offspring. This review also aims to propose and discuss cellular/molecular mechanisms framed within the 'free radical theory of ageing'. It appears that the ageing of gametes prior to fertilization may affect many molecular, biochemical and cellular pathways that may jeopardize not only pre- and post-implantation embryo/fetal development but also later life of offspring.…
New molecular markers for the evaluation of gamete quality.
2013
Purpose: Only 30 % of IVF cycles result in a pregnancy, so that multiple embryos need to be replaced, per treatment cycle, to increase pregnancy rates, resulting in a multiple gestation rate of 25 %. The use of new markers in the gamete selection, could reduce the number of the oocytes to be fertilized and embryos to be produced, but the tools to evidence the gamete competence remain unavailable and more studies are needed to identify bio-markers to select the best oocyte and sperm to produce embryos with higher implantation potentiality. Methods: To define oocyte competence, the apoptosis of the surrounding cumulus cells and the oxygen consumption rates for individual oocytes before fertil…
Fetuin-B, a liver-derived plasma protein is essential for fertilization.
2013
SummaryThe zona pellucida (ZP) is a glycoprotein matrix surrounding mammalian oocytes. Upon fertilization, ZP hardening prevents sperm from binding to and penetrating the ZP. Here, we report that targeted gene deletion of the liver-derived plasma protein fetuin-B causes premature ZP hardening and, consequently, female infertility. Transplanting fetuin-B-deficient ovaries into wild-type recipients restores fertility, indicating that plasma fetuin-B is necessary and sufficient for fertilization. In vitro fertilization of oocytes from fetuin-B-deficient mice only worked after rendering the ZP penetrable by laser perforation. Mechanistically, fetuin-B sustains fertility by inhibiting ovastacin,…
Sin registro de donantes de gametos: cerca de treinta años esperando su creación
2015
En este estudio planteamos la necesidad de un registro de donantes de gametos y presentamos las claves de por qué no existe aún en España un registro de estas características. Frente a las consecuencias negativas que se pueden derivar de la inexistencia de este tipo de registro, reflexionamos sobre la conveniencia y oportunidad de crear una red de registros de donantes para la medicina del siglo XXI In this study it is stated the idea that a register for gametes donors is necessary and we identify the key points explaining why such a register does not exist in Spain. Facing the negative consequences derived from the nonexistence of register for gametes donors, we make a mental construction …