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Activity Number:
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286
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Type:
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Contributed
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Date/Time:
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Tuesday, August 8, 2006 : 10:30 AM to 12:20 PM
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Sponsor:
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Biometrics Section
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| Abstract - #306859 |
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Title:
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Tradeoffs between Power and 'Confounding' in a Small Microarray Experiment
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Author(s):
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Mary Putt*+ and Thomas Cappola
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Companies:
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University of Pennsylvania and University of Pennsylvania
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Address:
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621 Blockley Hall, Wayne, PA, 19104,
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Keywords:
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microarrays ; study design ; gene expression ; confounding ; cardiology
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Abstract:
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In a heart rejection study, microarrays were prepared from 7 cases during rejection and post-rejection, and from 7 controls without rejection. Initial SAM analyses of within-subject data (during versus post-rejection) showed little differential expression while between-subject comparisons (during-rejection versus controls) pointed to a number of differentially expressed genes. Of interest; do genes identified from between-subject comparisons reflect 'confounding' or are they directly involved with rejection? We propose a permutation test that combines the within- and between- subject comparisons to better identify genes directly associated with rejection. Power analyses suggest the study design may be useful for detecting differentially expressed genes when within-subject differences are somewhat smaller than those between-subjects, and when the level of confounding is small or moderate.
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