The addition of modest amounts of long ultraviolet light (UV-A) to 1/2 minimal erythema dose (MED) of sunburning irradiation (UV-B) produced erythema visible at 24 hr, the prototype of the photoaugmentation phenomenon. The results were the same whether UV-A was given before or after UV-B. Photoaugmentation could be demonstrated after an inverval of 6 hr between doses, but not after 1 day. Photoaugmentation has also been demonstrated clinically and histologically with two topical photosensitizers, coal tar and 8-methoxy-psoralen.
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http://dx.doi.org/10.1111/1523-1747.ep12608213 | DOI Listing |
Contact Dermatitis
April 2005
Photobiology Unit, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK.
Photopatch test (PhPT) interpretation is difficult and clinical relevance is not always apparent. A positive PhPT may reflect photocontact allergy or phototoxicity. We hypothesized that it may also reflect the additive or synergistic effects of a suberythemal reaction to a contact irritant [e.
View Article and Find Full Text PDFPhotodermatol Photoimmunol Photomed
December 1996
Department of Dermatology, Ullevaal Hospital, University of Oslo, Norway.
A number of sulphonamide-derived oral antidiabetics and diuretics were investigated for phototoxic properties, using different sources of light, by means of a photohemolysis test. Photohemolysis was obtained after irradiation with UVA, visible light and solar simulating irradiation. No phototoxic properties were seen when the test samples were exposed to UVB alone.
View Article and Find Full Text PDFArch Dermatol Res
October 1996
Department of Dermatology, Hamamatsu University School of Medicine, Japan.
Sparfloxacin, a quinolone antibacterial agent, frequently elicits photosensitive skin reactions. Our clinical studies of patients treated with sparfloxacin have demonstrated that this photosensitivity is primarily phototoxic and that a marked erythematous response is induced by sequential irradiation with ultraviolet A (UVA) and B (UVB) but not UVA or UVB alone, suggesting potential synergism between UVA and UVB. We evaluated the phototoxicity of this agent using in vitro DNA breaking activity and in vivo murine cutaneous responses.
View Article and Find Full Text PDFActa Derm Venereol
March 1987
The phototoxic reaction to doxycycline is provoked by long-wave ultraviolet light (UVA). It was shown by the in vivo mouse tail technique, measuring phototoxic edema, that the addition of medium-wave ultraviolet light (UVB) immediately after, immediately before and especially 24 h before the phototoxic trauma, enhanced the reaction more than could be expected from simple addition, thus demonstrating the importance of photoaugmentation in this process.
View Article and Find Full Text PDFA study was done to demonstrate quantitatively and graphically the way in which suberythemogenic doses of broadband UVA and UVB interact in producing a visible erythema. On the backs of fair-skinned human volunteers the minimal erythema dose (MED) was determined for polychromatic UVA and UVB. Increasing fractions of the UVA MED were given to sites already exposed to various fractions of the UVB MED resulting in sites exposed to various doses of both UVA and UVB.
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