Hi!

I'm a user of the no-longer existing Stanford Microarray Database (SMD), and very new to MeV.  We scan Agilent 4x44k gene-expression 2-color arrays using a Genepix 4000b scanner.  After gridding the array in the Genepix software (Axon), we get a ".gpr" result file.  What we used to do was load this (in combination with the image files in .tiff) in SMD and proceed to data filtering: select features for which intensities are 1.5x  over background in both colors, features that have a 3-fold change over the mean, and for which the values are found in 75% of the samples.  This would give us a preculstering file, a ".pcl" file.  We could then take this .pcl file and load it into Cluster/TreeView.

When I load multiple .gpr files in MeV using the file loader specific for GenePix files, I have no idea how the Cy5/Cy3 ratios displayed are calculated (background values removed from the feature value?  A 1.5x factor over background for each color?).  What columns of the .gpr files are used? 
I saw I can save the matrix file, it looks like a preclustering file.  Is there a way in MeV to proceed to filtering with .gpr files as I mentioned above?  I saw how to do for 75% of present data over the samples (percentage cutoff filter), but the 1.5x over background and 3-fold change, I can't find where…

Thank you for your help.  Sincerely,
Karl-Philippe.