Oligonucleotide Microarrays and Data Analysis

The GeneChip system (Affymetrix, Inc., Santa Clara, CA) can be used for oligonucleotide microarray analysis of CD34+ MDS cells. The detailed protocol for sample preparation and microarray processing is available from www.affymetrix.com. Because of the limited number of CD34+ cells and the low content of RNA in these hematopoietic stem cells, a double in vitro transcription technique (''nanogram-scale assay'') has been established. To assay 50 ng of total RNA, the standard Affymetrix target amplification protocol has been modified by using first-round cRNA product to generate a double-stranded cDNA that is then used for a second round of in vitro transcription for synthesis of the biotinylated cRNA. GeneChip image analysis is performed using the Microarray Analysis Suite 5.0 (Affyme-trix). Data are analyzed by the GeneSpring™ software version 5.1 (Silicon Genetics, Inc., San Carlos, CA).

Class membership prediction[5,6] refers to the process of statistically dividing clinical samples (e.g., bone marrow cells) into reproducible classes that have similar gene expression behaviors or properties. Using a ''training set'' a list of predictive genes that can be used to discriminate one group from other groups of samples (diseases) exclusively according to their gene expression profile is selected. In a second analysis, the predictive genes are used to analyze a ''test set'' of additional samples whose classes are currently not known to place such samples into already known classes.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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