Figure 1. Expression of periostin, S100A4, and CD40 in PDLF and GF analyzed by Northern blot. A pool of total RNA (20 µg) was isolated from cultured PDLF or GF from three donors. Equal amounts of RNAs were used from each cell passage. RNAs were blotted and hybridized serially with each cDNA probe for periostin, S100A4, and CD40. Blot was finally hybridized with a probe for human glyceraldehydes-3-phosphate dehydrogenase (GAPDH) as an internal standard. The results were representative of three independent repeats (n = 3).