Due to the lack of standard calibration samples such as are used in traditional chemical analysis it may be a problem to evaluate whether changes done to the microarray procedure actually improve the identification of truly differentially expressed genes.
We have confirmed a powerful and consistent cDNA microarray procedure that can be used to study minute amounts of biological tissue.
The microarray procedure alone was not expected to comprehensively identify the complete S. aureus essential gene list, but was applied as a screen to reduce the workload for the more robust but laborious PCR-based analysis.
Before starting the study, the laboratory personnel at both biopsy centres were trained by BlueGnome to perform the microarray procedure and analysis.
A calibration curve, consisting of several dilutions of cDNA of the reference used for the microarray procedure, was included for each gene to allow calculation of the relative starting quantities.
Nonetheless, the MTP and an equal proportion of oligo-dT primers were supplied for the reverse transcription step during the microarray target labeling procedure, to achieve the greatest coverage possible.
The application to discriminate among variants of FMDV is added to a number of microarray procedures used in virology to analyze multiple viral pathogens that belong to different virus families [ 18, 33], to detect specific viruses [ 34- 36] or to define genetic variations underwent by viruses [ 37, 38] [reviews in [ 39, 40]].
The patient and tumour characteristics are shown in table 1. Microarray procedures were similar to our pilot study [ 2].
Technical replicates (n = 19), randomly chosen from among the 125 study subject samples, were included in the study to assess variability in the labeling, hybridization, and chip steps of the microarray procedure.
Microarray Procedure was compliant with MIAME.
