SELENIUM SULFIDE ON EPIDERMAL TURNOVER 771 10 /• Conti(Smen) •l•su n{•) (9 rnerO kConh-•Conti or Selsun©---.l-- Conti [ Figure 1. Corneocyte counts in subjects shampooing every 4 days with either a nonmedicated shampoo (Conti) or an effective antidandruff agent (Selsun) Comparison of Effects of Selsun on Corneocyte Counts of Normal and Dandruff Scalps The question to be answered next was whether Selsun was equally capable of reducing the corneocyte count in subjects without dandruff. In short, does Selsun further depress the proliferative activity of an epidermis whose turnover is normal to begin with ? The subjects included those with and without dandruff. The pre- treatment value was the average of two counts at --4 and 0 days after Conti shampooing. The scalps were then shampooed with either Conti or Selsun every 4 days for 6 treatments. A final count was then ob- tained at the end of this 24-day period. Figure 2 shows that the corneocyte counts fell in both dandruff and nondandruff subjects more or less proportionately, although this cannot be conclusively stated since there were only 5 subjects in the normal group. It is quite certain, however, that Selsun brings about a sharp decline in the rate of horny cell production regardless of the original state of cell renewal. It is interesting that the final count in the dandruff

772 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS ß Oand'•ruff Non-d•ndruff Figure 2. ' Comparison of effects of Selsun in dandruff and nondandruff subjects. count is the control value The Conti group, while below the normal value, was not as low as the terminal value in the nondandruff group. Thymidine Radioautography The scalps of nondandruff subjects were shampooed with Selsun every 4 days for 6 times. The labeling index was determined before and after treatment for both the epidermis and the external root sheath of the upper keratinizing portion of the follicular epithelium, the infundikulum. Figure 3 demonstrates that Selsun reduced the labeling index of both epithelia a little more than 50%. It is noteworthy that the values for the epidermis and external root sheaths were almost exactly alike both before and after treatment. DISCUSSION These findings are informative with regard to the fundamental aber- ration in dandruff as well as the mode of action of antidandruff medica-