Primary human fibroblast culture in NPD medium. Panel A: Primary human fibroblast proliferation according to initial cell density: Primary human fibroblasts were seeded in replicate in a 96-well plate at two initial cell densities: five and ten thousand cells per well. After an overnight growth the cells were fixed and assayed by means of crystal violet dye retention method. The results are presented in O.D. values. Each column represents a mean O.D. of a given growth condition; the error bars denote the standard error of the mean. *Significant difference between DI and NPD for cell density of 5000 cells/well (p << 0.0001). **Significant difference between DI and NPD for cell density of 10000 cells/well (p << 0.0001). Panel B: Primary human fibroblast growth in complete medium: In a 24-well plate primary human fibroblasts were seeded in triplicate in NPD and DI based media. Next sets of triplicates (both in NPD and DI) were analyzed, by detaching and counting the viable cells, every 24 hours. The results are given in number of viable cells per well, the error bars denote the standard error of the mean.