Cm

0 2 4 6 8 10 12 14 16 18 log2 Signal Cy3

microarray experiments, thus omitting the need for RNA amplification. Currently, amplification is necessary for RNA samples smaller than 4 mg.

Another way of dealing with a limited size of samples is downscaling the size of the microarrays. Subsequent to the initial diagnostic research that has been performed on large, whole genome arrays, often a ''signature'' set of a limited number of genes that is specific for predicting a disease condition can be identified.1-1,2,4-1 So if the size of the array can be downscaled from thousands to several hundred of genes, an enormous reduction of sample size can be obtained. In addition, there is technical room to decrease spot size by optimizing spotting solution in combination with the slide surface, or by other printing methods using capillary tips as currently being developed at the UCSF Cancer Center (cc.ucsf.edu). As a welcome advantage, this would also reduce the cost of a microarray experiment, thus rendering microarrays suitable for diagnostic purposes. The breast cancer study by Van't Veer et al.[2] has now led to the foundation of the first company that offers commercial microarray-based testing for diagnostics (Ref. [13]; www.agendia.com).

Investigations in which the RNA quality or quantity is not sufficient for expression profiling may be approached by microarray comparative genome hybridization (CGH)[3,14] because the more stable DNA is used as target instead of RNA.

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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