54 ESTABLISHMENT OF PREGNANCY BY OVINE NUCLEAR TRANSFER EMBRYOS RECONSTRUCTED USING CAFFEINE-TREATED <i>IN VITRO</i> -MATURED OOCYTES AS CYTOPLAST RECIPIENTS
Notice bibliographique
Résumé
In embryos reconstructed by somatic cell nuclear transfer (SCNT), components of the oocyte cytoplasm are capable of reprogramming the somatic genome to control subsequent development. Although the mechanisms that control nuclear reprogramming are unknown, we have previously hypothesized that the occurrence of nuclear envelope breakdown (NEBD) and premature chromosome condensation (PCC) in the donor nucleus are beneficial. In previous studies we have demonstrated that treatment of ovine oocytes with caffeine (10 mM), a protein phosphatase inhibitor, increased the activities of both MPF and MAPK in enucleated oocytes (Lee and Campbell 2004 Reprod. Fertil. Dev. 16, 125) and additionally resulted in a significant increase in the occurrence of NEBD and PCC in donor nuclei. Furthermore, SCNT embryos reconstructed following caffeine treatment had significantly increased cell numbers at the blastocyst stage. More recently we have demonstrated that the use of caffeine treated ovine oocytes as cytoplast recipients can regulate the expression of several developmentally important genes in SCNT embryos, including Oct-4 and interferon-tau (Choi et al . 2006 Reprod. Fertil. Dev. 18, in press). This study was designed to establish the developmental potential of NT embryos reconstructed using caffeine treated oocytes as cytoplast recipients. Ear skin fibroblast cells established from a Merino ram were quiesced in DMEM containing 0.1% fetal bovine serum (FBS) for 3 days. Oocyte maturation and embryo reconstruction and culture were performed as previously described (Lee and Campbell 2004 Reprod. Fertil. Dev. 16, 125) with the exception that ovaries from Merino × Romney Marsh cross ewes were stimulated with FSH sponge (Folltropin®-V; Bioniche Animal Health, Beltsville, Ontario, Canada) and were collected at slaughter on Day 13 following sponging. Blastocyst stage embryos were surgically transferred to the uterine horn of synchronized Merino × Romney Marsh cross recipients (three blastocysts per recipient). Recipient ewes were scanned by ultrasonography at Days 30, 60, and 90 following embryo transfer. All data were analyzed by chi-square test. There were no differences in fusion (145/167; 86.8% vs. 174/205; 84.9%), cleavage (123/145; 84.8% vs. 135/174; 77.6%), or the development to blastocyst (33/145; 22.8% vs. 34/174; 19.5%) between control SCNT embryos and caffeine treated SCNT embryos. However, although the frequency of pregnancy between control and caffeine-treated NT groups (5/15; 33.3% vs. 7/14; 50.0%) at 30 days was not significantly different, control SCNT embryos showed significantly lower pregnancies (1/15; 6.7%) than caffeine treated SCNT embryos (4/14; 28.6%) at both 60 and 90 days. In conclusion, embryos reconstructed using caffeine-treated cytoplasts can induce pregnancy at the same frequency as untreated controls; furthermore, the results suggest that SCNT embryos produced in this way are more able to maintain pregnancy.
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 machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,001 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,003 | 0,001 |
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 source (Gemma direct ou Codex distillé), 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 ».