Photoaugmentation is the potentiation of UVB-induced cutaneous erythema by UV irradiation. We have examined other cutaneous responses to UVB irradiationthe 4 hr depression of DNA synthesis, the 48 hr stimulation of DNA synthesis, and the induction of ornithine decarboxylase (ODC), to determine whether these were also susceptible to augmentation by UV A, which does not cause these responses when administered alone. No photo augmentation of DNA synthesis, stimulation or ODC induction occurred.

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... early depression of DNA synthesis was s lightly augmented but this did not consistently reach s ignificance. While investigating possible protective effects of UV A-induced immediate pigment darkening upon UVB-induced eryt hema in huma ns, Willis, Kligm a n, and Epstein [1] found that