Photosensitization Reactions of Fluoroquinolones and Their Biological Consequences

This review focuses on damage photosensitized by the fluoroquinolone (FQ) antibacterial drugs. Different models are employed to study biosubstrate photodamage mediated by FQs (organisms, cells, isolated biomolecules and super molecules). Being that the effect of environment (polarity of the medium, ions, pH, binding with bio‐molecules, etc.) is crucial in FQ photochemistry, photobiological reactions can be consequently dramatically influenced. Thus, the photosensitization processes induced by FQs are here discussed taking into account that such extensive and cross‐targeted pathological implications request an excursus covering photosensitization in systems of increasing molecular complexity. In vivo and in vitro evidences for photoallergy, phototoxicity, photomutagenesis and photocarcinogenesis mediated by FQs are discussed.     

Hierarchical Spherical Model from a Geometric Point of View

A continuous version of the hierarchical spherical model at dimension d=4 is investigated. Two limit distributions of the block spin variable X ^γ , normalized with exponents γ=d+2 and γ=d at and above the critical temperature, are established. These results are proven by solving certain evolution equations corresponding to the renormalization group (RG) transformation of the O(N) hierarchical spin model of block size L ^d in the limit L ↓1 and N→∞. Starting far away from the stationary Gaussian fixed point the trajectories of these dynamical system pass through two different regimes with distinguishable crossover behavior. An interpretation of this trajectories is given by the geometric theory of functions which describe precisely the motion of the Lee–Yang zeroes. The large-N limit of RG transformation with L ^d fixed equal to 2, at the criticality, has recently been investigated in both weak and strong (coupling) regimes by Watanabe (J. Stat. Phys. 115:1669–1713, 2004) . Although our analysis deals only with N=∞ case, it complements various aspects of that work. D.H.U. Marchetti partially supported by CNPq and FAPESP. W.R.P. Conti supported by FAPESP under grant 05/57416-8.