Background: The penetration of different wavelengths of UV radiation throug
h human skin is of major importance, especially for the determination of ph
otoprotective properties of sunscreens and UV-protective clothes. Objective
: In this study we present a new method for the measurement of UV transmiss
ion through small skin specimens. Methods: The transmission measurements we
re performed by using a UV spectrophotometer with an integrating sphere ope
rating in the wavelength range of 280-390 nm. For the skin samples, special
quartz glass cuvettes were developed which allowed measurements for very t
hin and small skin specimens. Furthermore, the cuvettes prevented dehydrati
on of the specimens and guaranteed, by using an additional diaphragm, that
the transmission data were derived solely from the small skin specimen exam
ined. Specimens measuring 8 x 3 mm(2) with a thickness of 0.3 mm (histometr
ic and sonographic control) were taken from the thighs of 10 subjects via s
have biopsy. Results: in the UVA range (315-390 nm) we obtained a mean tran
smission of 4.6% and for the UVB range (280-315 nm) of 0.9%, No significant
(p > 0.14) difference of UV transmission was found between the individual
skin specimens. Conclusion: This new method seems to be well suitable for U
V transmission measurements of small skin specimens. As UVA radiation has a
much deeper penetration depth and in in vivo situations dermal hemoglobin
could have an effect on UV penetration, the present method is better suitab
le for the investigation of UVB-induced biological adaptation mechanisms an
d the impact of topical agents on UVB transmission of the epidermis. Copyri
ght (C) 2000 S. Karger AG, Basel.