Metal-Free Catalyzed Synthesis of Fluorescent Indolizine Derivatives.

A mild and high efficient method to prepare indolizines by two-component reaction with the acid as the catalyst was developed. In this reaction, a new ring efficiently formed in one-step reaction. A wide range of substrates could be applied and the desired products were obtained in 8-95% yields under metal-free conditions. Different indolizine derivatives (compounds 3a-3n) were synthesized by general conditions and microwave irradiation conditions, and compound 3a gave the best results with an isolated yield of 95% and 82%, respectively. The structures of synthesized compounds were characterized by spectral analysis, and compound 3m was confirmed by single crystal X-ray analysis. UV-vis absorption and fluorescence properties of these compounds were correlated with substituent groups on indolizine rings.

An imidazo[1,5-α]pyridines-based ratiometric fluorescent probe for sensing sulfur dioxide derivatives in real samples based on a FRET mechanism.

A novel fluorescence resonance energy transfer (FRET)-based ratiometric emission fluorescent probe AT was designed and developed in which the imidazo[1,5-α]pyridine was served as a FRET donor and tricyanofuran (TCF) as the FRET acceptor to detect SO32-/HSO3- based on the Michael addition reaction. Probe AT had a high energy transfer efficiency (95%) and a large pseudo-Stokes shift (259 nm) in EtOH/PBS buffer (5/5, v/v). It also possessed good selectivity and quick response to SO32-/HSO3-. There was good linearity between the ratio of fluorescence intensity (F499/F645) and the concentrations of SO32-/HSO3- in the ranges of 1.5-7.5 µM and 9-20 µM, with calculated detection limits (LOD) of 55 nM. In addition, the probe could also detect the concentrations of SO32-/HSO3- in real samples such as environmental water and sugar, allowing the probe to be used in a variety of applications.

Identification of urine PLK2 as a marker of bladder tumors by proteomic analysis.

OBJECTIVE: To determine the patterns of urinary proteins in bladder cancer subjects using pooled urine from 27 bladder cancer patients. METHODS: The urine matrix was removed by acetonitrile precipitation followed by molecular weight cutoff. High performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) was used to analyze the urinary proteome. The candidate protein was validated by western blot. RESULTS: A total of 146 urinary proteins were identified. The protein list was screened using bioinformatic tools, and 11 cancer-related urinary proteins were found to be potential tumor markers for bladder cancer. However, only PLK2 was identified with high confidence. This candidate protein was validated by western blot using urine samples from 14 normal subjects and 10 bladder cancer patients. Statistically significant correlations were detected between PLK2 expression and bladder transitional cell carcinoma (TCC) (P < 0.05). Urinary PLK2 had a sensitivity of 80% at a specificity of 64% for bladder TCC in the samples tested. CONCLUSIONS: Our results demonstrate overexpression of PLK2 in bladder carcinomas, suggesting a possible role of PLK2 in the pathogenesis of bladder carcinomas. However, the small cohort, preliminary results, and lack of subgroup analysis (such as carcinoma in situ, high grade, and stage) in this study prevent us from drawing definitive conclusions about the diagnostic value of PLK2 in these patients. Further studies directed toward a multitude of possible carcinogenic mechanisms of PLK2 in bladder cancer are warranted.