Design, synthesis and preliminary biological evaluation of 5,8-dihydropteridine-6,7-diones that induce apoptosis and suppress cell migration.

Pteridines are an important class of fused heterocycles found in natural products and drug molecules, and have shown diverse biological activities. A focused library of 5,8-dihydropteridine-6,7-dione derivatives were designed and evaluated for their antiproliferative activity against MGC-803, SGC-7901, A549 and PC-3 cancer cell lines. The SARs studies highlighted the importance of the piperazine substituted 5,8-dihydropteridine-6,7-dione frameworks for the activity and revealed essential structural elements. Among these compounds, compound 5n displayed the most potent and broad-spectrum antiproliferative inhibition against the tested cell lines and was sensitive to MGC-803 cell line, slightly more potent than 5-FU. Preliminary mechanistic studies showed that compound 5n could inhibit the colony formation and migration of MGC-803 cells. Besides, flow cytometry analysis showed that compound 5n concentration-dependently induced apoptosis of MGC-803 cells. Our studies suggest that the piperazine substituted 5,8-dihydropteridine-6,7-dione frameworks may be regarded as new chemotypes for designing effective antitumor agents targeting gastric cancer cells.

Non-centrosymmetric Selenides AZn4 In5 Se12 (A=Rb, Cs): Synthesis, Characterization and Nonlinear Optical Properties.

Two new non-centrosymmetric polar quaternary selenides, namely, RbZn4 In5 Se12 and CsZn4 In5 Se12 , have been synthesized and structurally characterized. They exhibit a 3D diamond-like framework (DLF) consisting of corner-shared MSe4 (M=Zn/In) tetrahedra, in which the A+ ions are located. Both compounds are thermally stable up to 1300 K and exhibit large transmittance in the infrared region (0.65-25 µm) with measured optical band gaps of 2.06 eV for RbZn4 In5 Se12 and 2.11 eV for CsZn4 In5 Se12 . Inspiringly, they exhibit a good balance between strong second harmonic generation (SHG) efficiency (3.9 and 3.5×AgGaS2 ) and high laser-induced damage thresholds (13.0×AgGaS2 ). Theoretical calculations based on density functional theory (DFT) methods confirm that such strong SHG responses originate from the 3D DLF structure.

Detection of new bunyavirus RNA by reverse transcription-loop-mediated isothermal amplification.

Severe fever with thrombocytopenia syndrome (SFTS) is a newly emerging and epidemic infectious disease in central and northeast China. It is caused by New Bunyavirus and carries an average 12% case fatality rate. Early and rapid detection is critical for prevention and control of New Bunyavirus infection, since no vaccine or antiviral drugs are currently available, and prevention requires careful attention to control of the suspected tick vector. In this study, a simple and sensitive reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay was developed for rapid detection of New Bunyavirus. The detection limit of the RT-LAMP assay was approximately 10(3) 50% tissue culture infective doses/ml of New Bunyavirus in culture supernatants, and no cross-reactive amplification of other viruses known to cause similar clinical manifestations was observed. The assay was further evaluated using 138 specimens from clinically suspected SFTS and 40 laboratory-proven hantavirus infection with fever and renal syndrome patients, and the assay exhibited 97% agreement compared to real-time RT-PCR and conventional RT-PCR. Using real-time RT-PCR as the diagnostic gold standard, RT-LAMP was 99% sensitive and 100% specific. The RT-LAMP assay could become a useful alternative in clinical diagnosis of SFTS caused by New Bunyavirus, especially in resource-limited hospitals or rural clinics of China.

Raman Spectra of Porous beta-TCP Bioceramics Implanted into Rabbit Femur.

The Raman spectra of porous beta-TCP(beta-tricalcium phosphate)bioceramics implanted into rabbits femur the boundary and rabbit femur were studied using Raman spectroscopy(excited with 514.5nm and 623.8nm laser)and near-infrared FT-Raman spectroscopy. The Raman characteristic frequencies were assigned. The advantages and disadvantages of visible and near IR excitation are described. The Raman characteristic frequencies of calcium phosphate collagen protein and lipid(or phospholipid)were shown in the Raman spectra. These results demonstrated that besides calcium phosphate collagen protein and lipids also existed in the implants and the boundary forming components of organic bone tissues. Results indicated that the beta-TCP bioceramic when implanted into rabbit femur was partly dissolved and degraded the new bone tissues were formed on the surface and in pores of implanted bioceramics.