NONINTRUSIVE TESTING OF SKIN 25 Table III Projected Areas of Corneocyte½ Cohort Volar Forearm Upper Inner Arm 35 838.7 _+ 17.4 984.4 _+ 29.6 60 936.4 + 46.1 1,076.3 + 36.3 •Values are means _+ S.E. in/a 2. I]00 - 1200 - I100 - I000 - 900 - 800 - 700 - 600 --/- I 20 VOLAR FOREARM o ß ß o o CI• 0 Oß ß ß ß ß o o ß o o ß ß ßß ß I I I I I I I 30 40 50 60 70 80 90 SUBJECT CHRONOLOGICAL AGE Figure 9. Scatter plot showing the projected areas of exfoliated corneocytes from the volar forearm of human subjects of different ages. accounts for this extraordinary spread of values among aged individuals is perhaps one of the most important questions we can ask. By correlating ethnic origins, occupa- tional histories, life styles, etc. with age-associated differences revealed by our nonintrusive testing procedure, we hope to estimate the relative importance of genetics, environment and other factors which clearly contribute to "aging." Thus we anticipate that the knowledge gained will serve as the foundation for the development of effective therapeutic and prophylactic treatment for easing dermatological prob- lems associated with "aging." REFERENCES (1) A.M. Kligman,J. Invest. Dermatol., 73, 39 (1979). (2) F. A. Schellander andJ. T. Headington, Brit. J. Dermatol., 91,507-515 (1974).

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