Initial Experience with Topical Fluorouracil for Treatment of HIV-Associated Anal Intraepithelial Neoplasia.

Exposure to high-risk strains of human papillomavirus (HPV) promotes cellular dysplasia of the anal canal epithelium, potentially leading to anal intraepithelial neoplasia (AIN), which is in turn a precursor to invasive squamous cell carcinoma of the anus (SCCA). People with HIV infection who engage in anoreceptive intercourse are at heightened risk for acquiring HPV, AIN, and SCCA. Although intravenous 5-fluorouracil (5-FU) is commonly used for treatment of invasive SCCA, there has been little experience with the use of topical 5-FU as therapy for AIN. We retrospectively reviewed records of the first 11 HIV-positive patients treated with topical 5-FU in our anal dysplasia clinic. Six (55%) patients had clinical improvement with reduction in area of dysplasia seen on high-resolution anoscopy (HRA). Three (27%) patients had improvement in AIN pathologic grade. Eight (73%) patients reported mild-to-moderate perianal irritation, which led six to reduce the frequency of 5-FU application. Further study of topical 5-FU for treatment of HIV-associated AIN is warranted.

Tunable photochromism of spirooxazines via metal coordination.

Through the incorporation of a phenanthroline ligand into the oxazine moiety of photochromic spirooxazines, a series of photochromic spirooxazine-phenanthroline metal complexes have been synthesized, resulting in tunable and significantly increased photoresponsivities. Such systems are of interest for the investigation of multifunctional photochromic materials. These novel metal complexes retain their photochromic activity in the complexed state, leading to ligand binding in both the spirooxazine and the photomerocyanine forms during the photoconversion. A significant stabilization of the photomerocyanine form results from metal complexation, as indicated by the shift in thermal equilibrium values (KT = 0.06) upon metal complexation (KT = 0.6-1.2). Photoconversion occurs with first-order kinetics, suggesting the absence of an intermediate state. A third photostationary state is observed in these systems induced by visible irradiation of the thermal equilibrium state, leading to a three-state system. This new class of compounds provides the opportunity to investigate the synergy between changes in electronic structure associated with photoisomerization, and metal-centered functionality.