of the epidermis increased significantly p lt 0 01 in the test groups treated with formulation i and formulation ii as compared to the untreated group controls this was due to an increase in the number of cells as well as an increase in the size of the cells there was not significant difference in epithelial thickness between the formulation i and formulation ii treated groups the 100 mg thick skin slices were minced in 3 ml of minimal essential media mem with 20 u03bcci h 3 thymidine the mixture was incubated for three hours at 37 u00b0 c and cooled to 4 u00b0 c the supernatant was discarded and the solid phase rinsed with 10 ml of cold saline and incubated with 3 ml of 1 n naoh for 15 minutes min at 37 u00b0 c the solid phase was homogenized in a polytron and reincubated for 35 min at 37 u00b0 c and cooled to room temperature r t the addition of 1 5 ml of 2 n hcl neutralized the ph of the mixture which was subsequently cooled to 4 u00b0 c and an equal volume of 105 trichloroacetic acid tca was added the mixture was allowed to stand for 15 min at 4 u00b0 c centrifugation for 10 min at 2000 g produced a pellet the supernatant was discarded and the pellet resuspended in 5 ml 5 tca this centrifugation step was repeated 3 times in order to remove any free h sup 3 thymidine the pellet was.