48 MORPHOLOGICAL ANOMALIES OF FETAL MEMBRANES DURING GESTATION IN BOVINE CLONES DERIVED BY SOMATIC NUCLEAR TRANSFER
Notice bibliographique
Résumé
High pregnancy loss and prenatal morbidity and mortality encountered in cloned animals might be explained by placental nutritional or steroidogenic insufficiency that would indirectly compromise fetal survival (Hashizume et al. 2002 Cloning and Stem Cells 4(3), 197-209). Our hypothesis is that ultrasonographic characterization of placenta in bovine clones could be used to predict anomalies in fetal development and well-being during pregnancy. We examined surrogate heifers bearing cloned fetuses ( n = 37) and fetuses obtained by traditional embryo transfer ( n = 5) in three stages of gestation (Day 70, 100 and 200). Morphological parameters based on direct ultrasonographic observations were collected: thickness and shape of amniotic membrane, utero-placental thickness, placentomes shape and length in fetal area, and umbilical cord shape and appearance. Analysis was done using repeated measures linear model, with day as a repeated factor. Of all clone pregnancies, 30 females were still pregnant at Day 70 and only 16 reached Day 100, from which 63% had different degrees of amniotic and/or umbilical cord anomalies. No placental anomalies or abortions were observed in the control group. The amniotic membrane abnormalities observed at Day 100 were irregularities and presence of nodules (rosary-like) in the cross-sectional view of the membrane. Hyperechogenic spikes or irregularities around the umbilical cord were observed at Day 100 in 38% of the clones ( n = 6) and all of them also had amniotic anomalies. From the clone pregnancies with amniotic and/or umbilical cord problems, 30% aborted between Days 100 and 200, and for those that went to term (Days 264-278; n = 7), all calves but one died at birth or during the first month of life. Statistical analysis results showed that placentomes in cloned embryos were larger than those in control embryos ( P = 0.003; least-squares mean (LSM) for clone = 4.34 cm, control = 2.97 cm) in all three stages of gestation. During the same period, amniotic membranes of clones became thicker compared to those of the control group ( P = 0.0001; LSM for clone = 0.25 cm, control = 0.11 cm). Variation in utero-placental thickness was also observed. At Day 70, the utero-placental layer was thicker in clones in comparison to controls (LSM for clone = 0.32 cm, control = 0.30 cm) before it became thinner at Day 200 (LSM for clone = 0.38 cm, control = 0.40 cm). The present results showed that morphological anomalies of placentomes, amniotic membrane and umbilical cord appear during gestation of bovine cloned fetuses that could potentially compromise normal fetal development. Also, ultrasonographic monitoring of pregnancies of cloned animals is a useful tool to characterize the fetal membrane changes. This work was funded by a Strategic Project Grant from the Natural Sciences and Engineering Research Council (NSERC) Canada.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».