FRET mechanism between a fluorescent breast-cancer drug and photodynamic therapy sensitizers

Tamoxifen is one of the most frequently used drugs for the treatment of estrogen receptor positive breast cancer, which is the most prevalent form of hormone dependent breast cancer. A few years ago, we developed a fluorescent derivative of tamoxifen formed by the covalent binding of tamoxifen to a common dye biomarker. The new compound, known as FLTX1, showed the pharmacological activity of the tamoxifen moiety and efficient fluorescence properties, which could be used synergistically to improve the effect of the drug. In this paper, we demonstrate that irradiation at the absorption band of FLTX1 can result in fluorescence resonance energy transfer to photosensitizers such as Rose Bengal and Merocyanine 540, activating the production of reactive oxygen species (ROS). Indeed, the generation of ROS was demonstrated using a colorimetric assay. Since FLTX1 mostly binds estrogen-receptor overexpressing cancer cells, the results obtained are very promising and suggest a new therapeutic strategy combining chemo- and photodynamic therapies.

Metal-free, direct conversion of α-amino acids into α-keto γ-amino esters for the synthesis of α,γ-peptides

An efficient, metal-free synthesis of unusual α-keto γ-amino esters from α-amino acids is achieved by a radical scission–oxidation–addition of silyloxy acrylates procedure, where no purification of the reaction intermediates is needed. The process allows the synthesis of α,γ-peptides.

Synthesis of 2,3-disubstituted pyrrolidines and piperidines via one-pot oxidative decarboxylation-beta-iodination of amino acids

A new synthesis of 2,3-disubstituted pyrrolidines and piperidines is described. This mild procedure is based on the one-pot oxidative decarboxylation-beta-iodination of alpha-amino acid carbamates or amides. The iodine is introduced at the previously unfunctionalized 3-position. Different substituents can be introduced at C-2, e.g., hydroxy, alkoxy, allyl, alkyl, etc. A trans relationship between the C-2 and C-3 substituents is exclusively obtained. The influence of the solvent and the ring size of the starting amino acid are studied, as well as the nature of the protecting group on the nitrogen. The stereoselectivity of the reaction was also studied using chiral methyl (2S,4S)-4-acetyloxyproline-1-carboxylate (8). The products obtained can be manipulated to give bicyclic systems present in many natural products. By using the tandem decarboxylation-iodination-alkylation reaction, 2-substituted-3-iodopyrrolidines are formed, which are precursors of 2-substituted-2,5-dihydropyrrols.

Haemophilus aphrophilus as a rare cause of arthritis

A case of septic arthritis due to Haemophilus aphrophilus is presented. This organism has rarely been reported as a cause of bone or joint infections. We believe this is the third reported case of septic arthritis caused by this microorganism. We review the clinical and bacteriologic findings and the previously reported cases of infection caused by H. aphrophilus. Treatment with ceftriaxone was followed by full recovery without sequelae.