Wavelength dependence of ultraviolet-induced DNA damage distribution: involvement of direct or indirect mechanisms and possible artefacts.

DNA damage profiles have been established in plasmid DNA using purified DNA repair enzymes and a plasmid relaxation assay, following exposure to UVC, UVB, UVA or simulated sunlight (SSL). Cyclobutane pyrimidine dimers (CPDs) are revealed as T4 endonuclease V-sensitive sites, oxidation products at purine and pyrimidine as Fpg- and Nth-sensitive sites, and abasic sites are detected by Nfo protein from Escherichia coli. CPDs are readily detected after UVA exposure, though produced 10(3) and 10(5) times less efficiently than by UVB or UVC, respectively.

Cell survival and shuttle vector mutagenesis induced by ultraviolet A and ultraviolet B radiation in a human cell line.

Although it is known that sunlight is carcinogenic,few molecular data are available concerning the mutagenic effects of ultraviolet (UV) B (290-320 nm) and UVA (320-400 nm) radiation in human cells. To analyze the biologic effects of UVA and UVB, we irradiated the 293 human cell line, derived from adenovirus-transformed human embryonic kidney cells, in which we had stably introduced a shuttle vector harboring the lacZ' bacterial gene as the mutagenesis target. Identical cell survival occurred after UVA doses 700-fold higher than UVB.

[Dermatologic risks of quartz-halogen lamps].

Halogene sources are used increasingly in general illumination. Their quartz envelop is technically necessary, but presents the disadvantage of to letting the emitted UVA, UVB and UVC go through. Originally used as in indirect lighting, they have been introduced as desk-top lamps, without filter.

Erythema induced by quartz-halogen sources.

The erythemal effect of 100-W quartz-halogen sources, previously predicted from radiation measurements, was directly measured on humans at a distance of 10 cm. Minimal erythema was produced in 15 min for skin type I. These data show that normal use of a desktop lamp should not usually lead to erythema in one day, but that long-term effects cannot be ignored, because for lifetime use at work, the relative risk for squamous cell carcinoma on the back of the hands is 3.

Determination of 23 polycyclic aromatic hydrocarbons in atmospheric particulate matter of the Paris area and photolysis by sunlight.

Twenty-three polycyclic aromatic hydrocarbons (PAH) were determined in atmospheric particulate matter in 4 places of the Paris area at several times of the year. Fractionation was performed by reversed-phase high-pressure liquid chromatography. Determination was done by recording emission or excitation fluorescence spectra via a stopped-flow technique.