References of "Drion, Pierre"
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See detailUtilisation répétée des gonadotropines exogènes dans le contrôle de la reproduction: justifications et effets secondaires potentiels
Drion, Pierre ULg; Houtain, Jean-Yves; MC Namara, M. et al

in Annales de Médecine Vétérinaire (1998), 142(2), 373-396

Gonadotropins of pituitary origin (follitropin -FSH-, lutropin -LH-, human menopausal gonadotropin -hMG) or trophoblastic origin (human chorionic gonadotropin - hCG- also called pregnant urine ... [more ▼]

Gonadotropins of pituitary origin (follitropin -FSH-, lutropin -LH-, human menopausal gonadotropin -hMG) or trophoblastic origin (human chorionic gonadotropin - hCG- also called pregnant urine gonadotropin -pU-, equine chorionic gonadotropin -eCG- also called pregnant mare serum gonadotropin -PMSG-) are largely used to treat infertility or to better control sexuality in various species of mammals: bovine, canine, caprine, equine, feline, human,ovine, porcine, rabbit, ... This manuscript reports the discovery of these molecules, describes their biochemical characteristics and gives the main indications (e.g. oestrus induction and synchronization, ovulation, superovulation, fertility improvement, anoestrus treatment, receptivity induction) in animals and human. Litterature data reporting on effects and possible side effects of their repeated use are presented. Due to slight differences in amino acids sequences, carbohydrates contents and tridimentionnal structures, repeated use of exogeneous gonadotropins may induce immunological reactions leading to non specific reactions and lower biological response. A reflection concludes this revue, pointing out the positive influence of the philogenetic distance existing between the species origin of the gonadotropin (human or equine) and the treated one, on the intensity of the immune reaction. [less ▲]

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See detailInfluence des régulations situées à l'interface du métabolisme et de la reproduction sur la folliculogenèse et la reprise des cycles en post-partum
Drion, Pierre ULg; Houtain, J. Y.; Drame, El Hadji Daour et al

(1998)

Le déroulement harmonieux de la sexualité de la femelle repose sur l'intégrité anatomique, histologique, biochimique et hormonale des structures ovariennes, hypothalamiques, hypophysaires et utérines ... [more ▼]

Le déroulement harmonieux de la sexualité de la femelle repose sur l'intégrité anatomique, histologique, biochimique et hormonale des structures ovariennes, hypothalamiques, hypophysaires et utérines impliquées, ainsi que sur le subtil dosage des différentes hormones et facteurs protéiques intervenant dans les régulations. La compréhension des mécanismes régulateurs - endocrines, autocrines et paracrines (voir cadre ci-dessous)- qui permettent l'alternance des phases de croissance folliculaire et lutéale constitue un prérequis indispensable à la maîtrise de la cyclicité de la femelle, à la gestion optimale d'un cheptel et plus particulièrement à l'optimisation du capital génétique qu'il représente pour l'éleveur. La présente synthèse vise à faire le point sur les connaissances actuelles relatives aux aspects morphologiques et aux mécanismes régulateurs de la formation des ovaires, de la folliculogenèse et de l'endocrinologie de l'activité ovarienne. [less ▲]

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See detailSide effects of repeated treatments with exogeneous gonadotropins in cattle, sheep and goats
Drion, Pierre ULg; Remy, Benoit; Mc Namara, Michael et al

(1997, September 13)

Presented in this paper are investigations on a possible side effect of repeated treatments with exogeneous gonadotropins in cattle, sheep and goats. First is given an historical approach of the discovery ... [more ▼]

Presented in this paper are investigations on a possible side effect of repeated treatments with exogeneous gonadotropins in cattle, sheep and goats. First is given an historical approach of the discovery of human and equine chorionic gonadotropins including their biochemical properties. This review is continued with a brief report of some basic notions concerning the immune system followed by the description of respective sensitivities of different species to repeated gonadotropic treatments. A summarized presentation of the results of our investigations and those of different authors on circulating antibodies against exogeneous gonadotropins in the same species is then proposed. A synthetic reflexion leads to point out the positive influence of the philogenetic distance between the species - source of the gonadotropins (human or equine)- and the treated species -human, bovine, caprine, ovine- on the intensity of the immune reaction. [less ▲]

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See detailRepeated high doses administration of eCG in cows submitted to an ovum pick-up experimental protocol: plasmatic eCG binding rate follow up
Drion, Pierre ULg; De Roover, R.; Houtain JY et al

(1997, September 12)

This study performed plasma eCG binding rates assay on 8 cows submitted to repeated and high doses eCG administration in an ovum pick-up experimental protocol (de Roover et al., Abs.). The cows were ... [more ▼]

This study performed plasma eCG binding rates assay on 8 cows submitted to repeated and high doses eCG administration in an ovum pick-up experimental protocol (de Roover et al., Abs.). The cows were divided in two groups. For each cow, blood samples were taken three times a week, before and during the period of treatments. Cows of the first group received 10 injections of eCG (2000UI; 4x1000 UI; 5x2000 UI) while cows of the second group received 5 eCG treatments (2000 UI).Statistical analysis of results was made using the "SAS General Linear Model Procedure (GLM)" with binding rate considered as dependent variable and animals, treatment, and stade (before or after treatment) as independent variables. A significative (p<0.01) difference was found between binding rates before and after the treatment in either the first or the second group. The two treatments were found to induce a significative (p<0.001) increase in binding rates when compared with values obtained before treatments. Even if all cows responded to treatments by a binding rate increase, the effect of the treatment differed significantly (p<0.01) from one cow to another which could be explained by a large individual variability. From this experiment, we conclude that production of eCG antibodies is a wide response in the cows herein presented and repeatedly submitted to high doses of eCG. This immune response appeared after three to five injections and binding rates remained elevated over weeks following the latest injection. Special care should be given to this active immunisation -that could explain refractoriness to treatments- if such repeated administrations high doses of eCG were applied in usual protocols. [less ▲]

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See detailAbsence of relation between the production of anti-PMSG antibodies and the receptivity or productivity of rabbit does
Theau-Clement, M.; Lebas, F.; Remy, Benoit et al

(1997, September 12)

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See detailBovine pregnancy-associated glycoprotein profiles as indicators of trophoblastic function after in vitro manipulation or culture
Ectors, Fabien ULg; Sulon, José; Delval, A. et al

in Reproduction in Domestic Animals (1997, February), 32(1-2), 52

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See detailLe clonage par transfert de noyau dans l'espèce bovine
Ectors, Fabien ULg; Delval, Alain; Beckers, Jean-François ULg et al

in Annales de Médecine Vétérinaire (1997), 141

A all in vitro cloning technique was developed in wich embryos from the first cycle nuclear transfer (cloning) were used as blastomere donor for the second cycle nuclear transfer (re-cloning). Such method ... [more ▼]

A all in vitro cloning technique was developed in wich embryos from the first cycle nuclear transfer (cloning) were used as blastomere donor for the second cycle nuclear transfer (re-cloning). Such method permitted to produce 14,5% of morulae and 14,9% of blastocysts after the first and second cycle of nuclear transfer, respectively. The rates of birth obtained after transfer of such embryos were 21,4% and 20,5% for first and second cyle respectively, corresponding to 6 and 5 calves for 28 and 24 transferred embryos. Unfortunately, gestation patholgies and an increase of birth weights were observed. It seems that the in vitro presence of gametes and/or embryos may be responsible of an alteration in the control of gene expression. [less ▲]

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See detailRegolazione della crescité follicolare e luteinica. Ovulazione, corpo luteo e luteolisi. Summa.
Drion, Pierre ULg; Ectors, F. J.; Hanzen, Christian ULg et al

in Riproduzione dei ruminanti (1997), 14(9), 17-25

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See detailRegolazione della crescité follicolare e luteinica. Folliculogenesi e atresia. Summa.
Drion, Pierre ULg; Ectors, F. J.; Hanzen, Christian ULg et al

in Summa (1997), 14(9), 5-16

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See detailRegolazione della crescité follicolare e luteinica. Ovulazione, corpo luteo e luteolisi
Drion, Pierre ULg; Ectors, Fabien; Hanzen, Christian ULg et al

in Riproduzione dei Ruminanti (1997), 14(9), 17-25

Most ovarian follicles (99.9%) will end up with follicular atresia. During antral stages atresia depends on a reduction of FSH levels secondary to estradiol and inhibin secretions by the dominant follicle ... [more ▼]

Most ovarian follicles (99.9%) will end up with follicular atresia. During antral stages atresia depends on a reduction of FSH levels secondary to estradiol and inhibin secretions by the dominant follicle. Plasma levels in estradiol higher than 12pg/ml for at least 12 hours in bovine will cause the reversal of the negative feed-back effect of estradiol on the hypothalamus inducing the preovulatory peak of LH. So that the ovulatory discharge does not occur prematurely, the dominant follicle also secretes GnSIF which desensitises the hypohtesis to the action of GnRH. After ovulation, the corupus luteum, a true endocrine gland, develops. [less ▲]

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See detailRegolazione della crescité follicolare et luteinica. Folliculogenesi e atresia. Summa
Drion, Pierre ULg; Beckers, Jean-François ULg; Ectors, Fabien ULg et al

in Riproduzione dei Ruminanti (1997), 14(9), 5-16

Hypophyseal production of FSH and LH depends on a pulsating secretion of GnRH by the Hypothalamus. At the beginning of the cycle, this secretion sets free the FSH from the hypothesis responsible for ... [more ▼]

Hypophyseal production of FSH and LH depends on a pulsating secretion of GnRH by the Hypothalamus. At the beginning of the cycle, this secretion sets free the FSH from the hypothesis responsible for follicular recruiment. The recruited follicles produce estradiol, inhibin and follistatin which reduce the FSH secretion (negative feed back) reducing their support to hormonodependant follicles which become atresic. The dominant follicle, subjected to internal self stimulation is not sensitive to the reduction in FSH levels and carries on synthesising more and more estradiol. [less ▲]

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See detailAnti-PMSG in sheep subjected annualy to oestrus synchronisation
Bodin, L.; Drion, Pierre ULg; Remy, Benoit et al

in Reproduction Nutrition Development (1997), 37

Estimation of the long-term consequences on reproduction performance of the oestrus synchronisation treatments that are annually applied to ewes was carried out on nine officially controlled dairy flocks ... [more ▼]

Estimation of the long-term consequences on reproduction performance of the oestrus synchronisation treatments that are annually applied to ewes was carried out on nine officially controlled dairy flocks in the Roquefort region of France. A hormonal treatment combining the insertion of a vaginal fluoro-gestone acetate (FGA) sponge for 14 days and the injection of about 500 IU of pregnant mare serum gonadotropin (PMSG) at withdrawal was applied to the ewes in seven of the nine flocks. The ewes in the two other flocks were used as controls. Blood samples were taken from each female just before the treatment (to test for the presence of residual antibodies) and 20 days after the PMSG injection. Anti-PMSG antibody binding rates were calculated for each blood sample. The residual binding rate increased with age and induce negative effects on the following years reproduction performances, ie, they increased the probability that the ewes would not become pregnant. [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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See detailProduction of anti-PMSG antibodies and its relation to the productivity of rabbit does
Lebas, F.; Theau-Clement, M.; Remy, Benoît ULg et al

in World Rabbit Science (1996), 4(2), 57-62

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See detailThe ovarian follicle in cow: in vivo growth and in vitro culture
Beckers, Jean-François ULg; Drion, Pierre ULg; Figueiredo, J. R. et al

in Reproduction in Domestic Animals (1996), 31

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See detailRegulation de la croissance folliculaire et lutéale. 2. Ovulation, corps jaune et lutéolyse
Drion, Pierre ULg; Ectors, Fabien; Hanzen, Christian ULg et al

in Point Vétérinaire (1996), 28

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See detailRégulation de la croissance folliculaire et lutéale: 2. Ovulation, corps jaune et lutéolyse
Drion, Pierre ULg; Ectors, Fabien ULg; Houtain, J. Y. et al

in Point Vétérinaire (1996), 28

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