References of "Scenzi, Otto"
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See detailFrom the germinal cells to the newborn animal: the transmission of genes and life through the generations
Drion, Pierre ULg; Scenzi, Otto; Ectors Francis et al

(1999, May)

During the last decade, the technology of reproduction progressed considerably leading to a certain availability of in vitro methods for fertilization, maturation of the oocyte and culture system for the ... [more ▼]

During the last decade, the technology of reproduction progressed considerably leading to a certain availability of in vitro methods for fertilization, maturation of the oocyte and culture system for the embryos. The most spectacular manipulations are cloning and transgenesis… This review focuses on the early appearance of the germinal cells precursors and the longstanding destiny of the gametes in mammals. The evident complexity and long-term programmation of events in gametes and early embryo explain the difficulties to succeed in in-vitro methods and the occurrence of unexpected alterations of development, e.g. embryonic or fetal mortalities, large weight newborn syndrome and other dys-regulations in imprinting or DNA transmission. “Studying and teaching the reproductive physiology in mammals, we sometimes imagine that a newborn animal survived two pregnancies: the first one would be a high risk pregnancy that represents the oocyte development and survival inside the follicle with a tetraploïd genome and the zona pellucida & cumulus cells as placenta-like structures. Around the first birth (ovulation), oocytes (individuals) accept in vitro conditions for maturation, fertilization and culture. Afterwards, a second pregnancy will be necessary in the mother or in the recipient uterus; a low risk pregnancy depending on the oocyte competence acquisition and on the conditions or length of exposure in vitro. “ [less ▲]

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See detailInterests of pregnancy follow-up in cows after embryo transfer : special focusing on IVP & NT
Ectors, Fabien ULg; Drion, Pierre ULg; Delval, A. et al

(1996, September 13)

In this report, pregnancies were obtained after extreme in vitro conditions- IVM/F/C of the donor embryos, - IVM, enucleation and artificial activation of the recipient oocytes, - nuclear transfer and ... [more ▼]

In this report, pregnancies were obtained after extreme in vitro conditions- IVM/F/C of the donor embryos, - IVM, enucleation and artificial activation of the recipient oocytes, - nuclear transfer and - IVC of the reconstituted embryos. Even if the incidence of this syndrome is relatively low after embryo transfer, a possible increasing of its occurence cannot be excluded in correlation with an incomplete maturation of oocytes at the time of fertilization, smaller follicles giving non competent or partially competent oocytes. An other explanation of this syndrome resulting in the higher variation in newborn calves weight may be also partly explained by the in vitro conditions. The gametes and/or embryos may be submitted to media containing embryotoxic substances. In the other hand, gametes and/or embryos may not found embryotrophic substances in the media like growth factors... Owing to this phenomenon, strict recommendations should be followed concerning rigorous follow-up of pregnancies obtained after transfer of IVM/IVF/IVC or cloned embryos by pregnancy proteins (PSPB, PAG...) or hormone (placental lactogen, estrone sulfate) assay and, after birth, macroscopic examinations of newborn, cord and caroncules. [less ▲]

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