Cas
Practical 1 - Omics
- Cours
- Établissement
Case of 5 pages for the course EPI4925 Molecular and Genetic Epidemiology at UM (Practical 1 - Omics)
[Montrer plus]
Vendeur
S'abonner
zoeverschueren
Avis reçus
Aperçu du contenu
Practical I – Biomarkers: from single markers to omicsQUESTIONS
1. What is the research question of the study by Chen et al, 2015? Does this study focus on
prediction or on understanding? Explain.
The aim of the study is to identify important metabolites to distinguish a normal metabolic state
from an abnormal obesity metabolome.
Explore the differences between the MHO and MAO groups
The focus of the study is understanding, because they want to find metabolomes that identify
potential metabolic pathways that may regulate the different metabolic characteristics of obesity.
Etiologic research
o Understand mechanisms
o Aim to establish causality
But also prediction
2. Does this study examine a biomarker of exposure, susceptibility, or (intermediate) endpoint?
Explain.
The biomarker is an endpoint, because the biomarker reflect the type of obesity, namely
metabolically healthy obesity (MHO) or metabolic abnormal obesity (MAO) group. So with the use of
metabolites one distinguish MHO and MAO.
Also an exposure and susceptibility marker
3. Are the metabolomics measurements performed targeted or untargeted? Explain the difference.
What are the advantages and disadvantages of both approaches?
Both a targeted and untargeted analysis was employed in this study.
Target measurement = used to estimate the importance of each metabolite within a specific
pathway.
- Hypothesis driven
- The metabolites you want to investigate are already identified (specific)
- Aim = absolute quantification of specific metabolites in biological samples
- Limited number of metabolites
Advantages:
- Used when you want to investigate a specific metabolite
Disadvantages:
- Require a priori knowledge of metabolites of interest
- Do not achieve global coverage
Untargeted measurement = quantify the global metabolic profile of a sample
- Hypothesis-generation
, Practical I – Biomarkers: from single markers to omics
- Collect and analyse all detectable metabolites in a sample
- You do not know the identification of the metabolites
- Compare differences (peaks) in metabolic profiles across different (sub)populations
- As many metabolites as possible
- Relatively easy automated high-throughput
Advantages:
- Reveal novel compound and chemical unknowns
- Leading to new insights in disease mechanisms or treatment
Disadvantages:
- You do not know the identity of the metabolites
Library = database that contains information to identify metabolites
4. Was the sample collection, handling, storage and analysis suitable for measuring
(metabol)omics data? Why (not)? Which issues should be taken into account?
What should be mentioned in the method section:
- Sample collection = blood samples after 8 hours of fasting
o Not mentioned time between sample collection and endpoint
- Storage = stored at -80 degrees of Celsius
o Not mentioned timing etc.
- Extraction = at 40 degrees of Celsius
The sample collection, handling, storage and analysis seems suitable for measuring omics data,
however limited information is mentioned.
Issues to take into account:
- Transport
- Laboratory errors
- Storage effects
- Freeze-thaw cycles
- Batch effects
You need a quality control sample
5. Did the authors use univariate and/or multivariate statistical methods for analyzing their data?
What are the differences and/or advantages of both approaches?
Therefore the author use univariate statistical methods, because there is only one outcome MAO
= yes/no logistic regression
However, it is a multivariate methods, because they are looking at all the metabolites together
- PLSDA
- Principal component analysis
- Repeated measures ANOVA
Complex data driven explorative
Les avantages d'acheter des résumés chez Stuvia:
Qualité garantie par les avis des clients
Les clients de Stuvia ont évalués plus de 700 000 résumés. C'est comme ça que vous savez que vous achetez les meilleurs documents.
L’achat facile et rapide
Vous pouvez payer rapidement avec iDeal, carte de crédit ou Stuvia-crédit pour les résumés. Il n'y a pas d'adhésion nécessaire.
Focus sur l’essentiel
Vos camarades écrivent eux-mêmes les notes d’étude, c’est pourquoi les documents sont toujours fiables et à jour. Cela garantit que vous arrivez rapidement au coeur du matériel.
Foire aux questions
Qu'est-ce que j'obtiens en achetant ce document ?
Vous obtenez un PDF, disponible immédiatement après votre achat. Le document acheté est accessible à tout moment, n'importe où et indéfiniment via votre profil.
Garantie de remboursement : comment ça marche ?
Notre garantie de satisfaction garantit que vous trouverez toujours un document d'étude qui vous convient. Vous remplissez un formulaire et notre équipe du service client s'occupe du reste.
Auprès de qui est-ce que j'achète ce résumé ?
Stuvia est une place de marché. Alors, vous n'achetez donc pas ce document chez nous, mais auprès du vendeur zoeverschueren. Stuvia facilite les paiements au vendeur.
Est-ce que j'aurai un abonnement?
Non, vous n'achetez ce résumé que pour €6,49. Vous n'êtes lié à rien après votre achat.
Peut-on faire confiance à Stuvia ?
4.6 étoiles sur Google & Trustpilot (+1000 avis)
67096 résumés ont été vendus ces 30 derniers jours
Fondée en 2010, la référence pour acheter des résumés depuis déjà 14 ans