Analysis of IL-6 mRNA levels within synovial tissue from rheumatoid arthritis (RA) as compared with that from osteoarthritis (OA) patients. Upper panels: quality control of total RNA preparations. Aliquots (300 ng) of total RNA extracted from synovial tissue from RA and OA patients were plotted on a RNA 6000 Nano-LabChip. Quality of RNA was scanned using a 2100 bioanalyzer. RNA gel electropherograms show the presence of 28S and 18S ribosomal units, indicating intact RNA of the investigated samples. Lower panels: differential IL-6 mRNA levels were determined by semiquantitative reverse transcription polymerase chain reaction (PCR). The figure shows a representative analysis of eight cDNA samples derived from patients with RA and of eight cDNA samples from patients with OA. cDNA samples were adjusted to equal glyceraldehyde-3-phosphate dehydrogenase (G3PDH) levels, performed by competitive PCR using an internal standard (see Materials and methods). Numbered lanes correspond to individual patients within Table 1.