Notice bibliographique
Résumé
Stem cell research has raised great interest in the scientific community as it has the potential to form multiple cell types and it is believed they hold the key to curing many diseases. However, there is a need for better understanding of how to control these cells and further research investigating methods for controlling and directing these cells is required. Pluripotent stem cells transplanted into immune-deficient mice 'spontaneously’ differentiate and proliferate to form a complex mass of differentiated and undifferentiated cells, teratomas - teratoma assay. Such tumours are generally haphazard in their organisation however; they do contain some structures similar to those observed in the embryo. Teratoma formation is a useful model to explore the developmental potential of stem cells and study aspects of tissue development. Examination of how the anatomical location into which human pluripotent stem cells are grafted influences their growth in situ allows investigation of how these cells are affected by different areas within the body: cells grafted into the liver rapidly produce large tumours containing predominantly immature cells whereas, subcutaneous implants were significantly slower growing and formed tumours composed of differentiated tissues. These different growth patterns indicate how environmental cues within the niche affect stem cell behaviour. One factor which contributes to the maintenance of a niche is the extracellular matrix (ECM). To investigate how endogenous ECM affects teratoma behaviour, co-transplantation is carried out with stem cells and ECM components. The ECM extract Matrigel™ dramatically increased the success rate of teratoma formation and size with no detectable affect on teratoma composition when compared to controls and removal of the growth factors from the co-transplanted ECM extract had no effect on teratoma success rate, growth rate, or composition. To study the effects of the ECM in vitro, components of the ECM are often used topcoat glass or plastic surfaces to enhance cell attachment in vitro. Fragments of ECM molecules can be immobilised on surfaces in order to mimic the effects seen by whole molecules. In this study a novel technology developed by Oria Protein Technologies for the immobilisation of peptide sequences from ECM proteins is evaluated. By examining: the adherence of cultured PC 12; neurite outgrowth from PC 12 cells; and neuronal differentiation of neural stem/progenitor cells (NSPCs) it is shown that peptides from collagen I, collagen IV, fibronectin and laminin can mimic surfaces coated with ECM proteins. Collectively, this data demonstrates that peptides from ECM proteins can be immobilised in functional fashion to control cell behaviour. Surfaces with adsorbed proteins and biomimetic surfaces presenting peptide motifs from ECM proteins are used to investigate and explain observations from in vivo teratoma experiments. In vivo, Matrigel™ increases the gene expression of the pluripotent stem cell marker Oct4, increasing the pluripotent cell percentage and thus increases the likelihood of teratoma formation. In vitro, Matrigel™ also increases the gene expression of the proliferative marker Ki67, indicating that large teratomas from by the co-transplantation of stem cells with Matrigel™ could be due to increased cell proliferation.
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) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 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) | 0,001 | 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 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 ».