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Among fluoroquinolone antibiotics, ofloxacin (OFL) and norfloxacin (NOR) have piperazinyl groups but flumequine (FLU) does not have this substitutent. The emission spectra of OFL and NOR are strong, broad structureless bands with large Stokes' shifts in water but the emission intensities are very weak in organic solvents. Thus we find that these compounds exist as different chemical species in various solvents. A continuous red shift in the emission bands for OFL and NOR is observed as the water concentration within the aerosol-OT (AOT; sodium 1,4-bis[2-ethylhexyl]sulfosuccinate) micelle increases or temperature of this solution rises. From the fluorescence anisotropy measurements of OFL and NOR, we assume the intramolecular charge transfer after excitation from the nitrogen of the piperazinyl group to the keto oxygen. Theoretical calculations further support this observation. Multifrequency phase and modulation experiments and time-resolved emission spectra clearly show the occurrence of intramolecular charge transfer and the subsequent nanosecond water reorganization around OFL or NOR in the AOT micelle. Upon increasing the water concentration within the AOT micelle, the relaxation rate increases because of the large amount of free water. The emission spectra of FLU do not exhibit any significant response to the physical properties of their environment.

BackgroundIt was previously thought that persons with genetic predispositions to vitiligo develop the condition after exposure to various precipitating environmental factors. However, in many cases, the aggravating factors of vitiligo have not been clearly identified.ObjectiveTo identify the aggravating factors of vitiligo in the working environment and daily life.MethodsA total of 489 vitiligo patients were recruited from 10 institutions in South Korea; patients were provided with a questionnaire about environmental factors and behavior patterns in the workplace and in daily life, and their association with vitiligo.ResultsNinety-five of the 470 enrolled patients (20.2%) answered that environmental risk factors in daily life and in the workplace affected the development of vitiligo. The most frequently attributed causes were trauma and burn (13.6%), followed by sunlight (12.8%), stress (12.8%), cleaning products/disinfectant/chemicals (4.9%), and hair dye (2.1%).ConclusionVitiligo of the hand and foot was associated with frequent exposure to aggravating materials and overexposure to sunlight, along with frequent trauma of these areas, all of which could be considered important risk factors of vitiligo. The development of vitiligo could potentially be controlled through the early detection of aggravating factors.

Although acute exposure to UV radiation suppresses the induction of delayed-type (DTH) and contact (CHS) hypersensitivity in mice, it is not clear whether the photobiological mechanism(s) involved in suppressing these closely related immune reactions is the same. A careful examination of the UV dose responses and wavelength dependencies involved in suppressing CHS and DTH may provide important insights into the mechanisms involved. We compared the UV dose-response curves for suppressing four closely related immune reactions, local and systemic suppression of CHS to dinitrofluorobenzene, systemic suppression of DTH to Candida albicans and systemic suppression of DTH to alloantigen using three different UV spectra (FS40 sunlamps, Kodacel-filtered FS40 sunlamps and solar-simulated light). For each immune response studied, the amount of UVB radiation required to induce 50% immune suppression was lowest when FS40 sunlamps were used, highest with solar-simulated light and intermediate when Kodacel-filtered FS40 sunlamps were used, but the differences observed were not statistically significant. The UV dose-response curves for immune suppression differed significantly depending on the assay used, the site of antigenic sensitization and the antigen used. These findings suggest that the mechanisms by which UV radiation induces immune suppression differ for the four immunological reactions studied.

In order to protect the public against the adverse effects of sunlight, the scientific, medical, and particularly the dermatologic community has promoted "safe sun exposure." This strategy includes sun avoidance whenever possible, wearing hats and other protective clothing and/or devices, such as sunglasses, and extensive use of sunscreens. Sunscreen efficacy is determined by measuring the ability of the sunscreen to block ultraviolet (UV)-induced erythema (sun protection factor or SPF), and most sunscreen formulations on the market, if used properly, are very good at preventing erythema and sunburn. How well sunscreens protect against the other adverse effects of sunlight, such as immune suppression, is not as clear. The purpose of this paper is to review and discuss the literature in this area, concentrating on some of the complications of determining how well sunscreens protect against UV-induced immune suppression.