32 ULTRASOUND MEASUREMENTS OF BOVINE SOMATIC CLONES AT DAY 50 AND DAY 64 OF PREGNANCY
Notice bibliographique
Résumé
The overall efficiency of cloning has stayed low since this technique appeared. Most of the losses in the bovine species take place in early gestation between Day 35 and Day 70, when deficient placental development has been described. Late fetal losses are associated with excessive fetal growth and placental hydrops (Large Offspring Syndrome or LOS). One study measuring crown-rump length (CRL) by ultrasound (US) did not show any difference between clones and controls (Pace et al., 2002). The objective of this work was to compare fetal and placental measurements at Days 34, 50, and 64 for bovine clones and control pregnancies to determine whether these could be predictive of a further development of LOS. Twenty-five clone and 32 control (28 AI and 4 IVF) singleton Holstein pregnancies were used for US with a 5-MHz rectal probe. Clones originated from adult skin fibroblasts (three genotypes), used after serum starvation, as previously published (Vignon et al., 1998). CRL and head length (HL), orbital diameter (OD), vesicle width (VW), and length and width of the placentome closest to the fetus were measured at each stage. CRL were also recorded from six clone, six IVF and five AI, Day 34 and Day 60 fetuses recovered at slaughter. Maternal clinical parameters, US images with increased fetal fluids, excessive weight, and clinical features at surgical removal or birth were used to diagnose LOS. Data were analysed using multiple regression analysis with SAS software. There were no differences between IVF and AI fetal and placental measurements by ultrasound and the two groups were pooled as a single control group. LOS was diagnosed in 29% of the clones. CRL and HL were significantly smaller in clones at all stages (CRL: 10.2 ± 3.8 mm, n = 5 v. 13.6 ± 2.4 mm, n = 7, at retrieval at Day 34; 31.8 ± 5.6 mm v. 36.0 ± 4.6 in controls at Day 50, by US, and 48.6 ± 11.4 v. 63.3 ± 4.9 at Day 64, by US, P < 0.05, in clones and controls, respectively) but there was no difference between the clones developing LOS and those that did not. There was no difference for OD or VW at any stage. Placentome width but not length was statistically smaller in clones compared to controls (4.8 ± 1.5 v. 7.2 ± 1.7 mm at Day 50 and 5.7 ± 2.0 v. 9.4 ± 4.2 at Day 64, in clones and controls, respectively, P < 0.05). There were only two clones retrieved at Day 64, one degenerated and the other similar to controls. Placentome development was delayed. These data clearly show that although a large proportion of clones develop LOS in late gestation, they are actually smaller than controls in early pregnancy, whether or not they will develop LOS. This is probably due to delayed or abnormal early placental development, which can be detected by US. US cannot be used, however, to predict further development of LOS, and other means such as maternal plasma PSP60 concentrations (Heyman et al., 2002) must be used.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
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 | 0,001 | 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 ».