Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:RT-PCR and expression analysis RNA isolations fromASCs and endothelial cells of 7 different patients were carried out using QIAmp RNABlood Mini Kit (Qiagen), and cDNAs were generated from 40 ng of RNA using the High-Capacity cDNA Reverse Transcription Kit (Applied Biosystems); quantitative real-time (qRT)-PCR was carried out with an ABI Prism 700 platform as previously described (Martin-padura and colleagues) using primers and probes from the TaqMan Gene Expression Assay (5).
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