time following the split of confluent cells in this experiment three replicates were performed the first replicate foreskin fibroblast primary cells hff1 used in this experiment was passage 18 p 8 whilst the first replicate of hypertrophic derived primary cells hsf1 was passage 4 p4 tables 7 12 and fig1 depict the results including the micro plate read outs for these experiments hff2 and hff3 are the second and third passages respectively i e passage 19 and 20 respectively of the foreskin fibroblast primary cells similarly hsf2 and hsf3 are the second and third passages respectively i e passage 5 and 6 respectively of the hypertrophic derived primary cells the cells were treated as above with the exception that each replicate was the result of a passage and that the cells were stained with sirius red which is a collagen specific stain levels of collagen in solution can be determined by staining with sirius red and analysing the absorbance at 540 nm to measure absorbance the acidic stain was first solublized in naoh methanol 2 5m mixture before analysis in the microplate reader at 540 nm the averaged results of the absorbance studies are tabulated in table 13 the fixed and stained plates of each.