[Reversal Effect of NVP-BEZ235 on Doxorubicin-Resistance in Burkitt Lymphoma RAJI Cell Line].

OBJECTIVE: To study the reversal effect of NVP-BEZ235 on doxorubicin resistance in Burkitt lymphoma RAJI cell line. METHODS: The doxorubicin-resistant cell line was induced by treating RAJI cells with a concentration gradient of doxorubicin. The levels of Pgp, p-AKT, and p-mTOR in cells were detected by Western blot. Cell viability was detected by MTT assay. IC50 was computed by SPSS. RESULTS: The doxorubicin-resistant Burkitt lymphoma cell line, RAJI/DOX, was established successfully. The expression of Pgp and the phosphorylation levels of AKT and mTOR in RAJI/DOX cell line were both higher than those in RAJI cell line. NVP-BEZ235 downregulated the phosphorylation levels of AKT and mTOR in RAJI/DOX cell line. NVP-BEZ235 inhibited the proliferation of RAJI/DOX cell line, and the effect was obvious when it was cooperated with doxorubicin. CONCLUSION: The constitutive activation of PI3K/AKT/mTOR pathway of RAJI/DOX cell line was more serious than RAJI cell line. NVP-BEZ235 reversed doxorubicin resistance of RAJI/DOX cell line by inhibiting the PI3K/AKT/mTOR signal pathway.

Four new diphenyl ether derivatives from a mangrove endophytic fungus Epicoccum sorghinum.

Four new diphenyl ethers, named epicoccethers K-N (1-4), were purified from the fermentation medium of a fungus Epicoccum sorghinum derived from Myoporum bontioides, and identified through HR-ESI-MS and NMR spectral analysis. Except that compound 1 showed moderate antifungal activity against Penicillium italicum and Fusarium graminearum, the other three compounds showed stronger activity against them than triadimefon. All of them showed moderate or weak antibacterial activity towards Staphylococcus aureus and Escherichia coli with O6 and O78 serotypes except that 3 was inactive to E. coli O6.

[Detection of Camellia Oleifera Oil Adulterated with Sunflower Oil with Near Infrared (NIR) Spectroscopy and Characteristic Spectra].

Camellia oleifera oil has the reputation of "oriental olive oil"; it is important to detect the adulterated camellia oleifera oil. In this paper, NIR spectra were used to detect camellia oleifera oil adulterated with sunflower oil. Camellia oleifera oil adulterated with varying mass fraction of sunflower oil were prepared, i. e., 11 samples in 0%～10% with the gradient of 1%, 6 samples in 15%～40% with the gradient of 5%, 6 samples in 50%～100% with the gradient of 10%, and all the samples were divided into four groups such as A(0%～5%), B(6%～10%), C(15%～40%) and D(50%～100%). A total of 207 absorbance spectra(1 000～2 500 nm) were acquired by sampling 9 times in each adulteration. Calibration set was consist of two-thirds of the spectra data in each group selected randomly, and the validation set was made up of the last spectral data. After removing the noise in both ends of the spectra, principal component analysis(PCA) was used to reduce the dimensionality, then the first four PCs were used to build the support vector machine (SVM) identification model, and the identification accuracies of 96.38% and 94.20% in calibration and validation set were obtained. Furthermore, five characteristic wavelengths (1 212, 1 705, 1 826, 1 905 and 2 148 nm) were selected based on the loading of the PCs, the peaks or troughs of the original spectra and the chemical functional groups they were corresponding to. A NIR simplified SVM identification model was built by them, and the identification accuracies were 94.20% and 92.75%. Overall, both NIR spectroscopy and NIR characteristic spectra can realize the identification of camellia oleifera oil adulterated with sunflower oil, and the characteristic wavelengths, selected in this study, provide a basis for the design of corresponding instrument.

[Optimization of Stabilizing Agent of Camptothecin Extraction from Nothapodytes pittosporoides Roots].

Objective: To optimize the stabilizing agent of camptothecin extraction from Nothapodytes pittosporoides roots. Methods: The single factor experiment had been conducted to study the impact on the yield of camptothecin with different kinds of stabilizer, stabilizer concentration and temperature. Results: The results showed that with 0. 5% ferrous sulfate at 80 ℃,the best concentration of camptothecin extraction from Nothapodytes pittosporoides roots was got, and the yield of camptothecin after concentration reached to 94. 58%. Conclusion: This process method is efficient and simple, which can be used to solve camptothecin reduction when the extract is concentrated, and the method is benefit for the industrialization of camptothecin extraction.

[Feasibility and outcome of rotational atherectomy for treating resistant chronic total occlusions].

OBJECTIVE: To assess the application of rotational atherectomy to improving the success rate and outcome of percutaneous recanalization of resistant chronic total occlusion (CTO), i.e. the guidewire could cross the lesion but it is impossible to advance any device over the wire through the occluded segment. METHODS: From August 2008 to December 2012, 26 consecutive patients with 27 resistant CTO lesions were additionally treated by high-speed rotational atherectomy (rotational atherectomy group). The control group included 751 non-resistant CTO lesions. Drug-eluting stents were implanted in two groups after the balloon catheter crossed the CTO lesions. The successful rate of rotational atherectomy and in hospital major adverse cardiovascular events (including cardiac death, interventional treatment related myocardial infarction and target vessel revascularization) were observed. RESULTS: The rate of heavily calcified coronary lesions was significantly higher in rotational atherectomy group than in the control group[63.0% (17/27) vs. 21.2% (159/751), P < 0.05] according to pre-procedural coronary angiography. Rotational atherectomy was successful in 25 out of 27 resistant CTO lesions (92.6 %). The rate of cardiac death [0 vs. 0.5% (4/751), P > 0.05], interventional treatment related myocardial infarction [38.5% (10/26) vs. 22.2% (167/751), P > 0.05] and target vessel revascularization [0 vs. 1.2% (9/751), P > 0.05] were similar between the rotational atherectomy group and the control group. CONCLUSION: Rotational atherectomy is a safe and helpful technique to overcome the inability of balloon catheter to cross a resistant CTO.

[A study on image processing of digital radiography and measure of material micro-density directly].

Due to the high influents of the device itself and the surrounding environment, the background brightness of the digital radiography image is uniform and the image shows big noise. Therefore, in order to identify digital radiography images precisely, a further image processing is necessary. In this study, adaptive filtering, histogram equalization techniques and difference image methods were used for image processing and the results show that these techniques were useful to denoise, to intensify brightness and to rectify the background. In order to verify the feasibility of these techniques, poplar wood samples of heterogeneous material were used as experimental materials and Micro-density was measured directly by applying the linear relationship between grey scale of DR image and penetrate material density and contrasted with the result of microdensitometer. The results show these techniques were feasible and even gave a more precise measurement on wood micro-density compared to microdensitometer.

Conformational changes in the reaction of pyridoxal kinase.

To understand the processes involved in the catalytic mechanism of pyridoxal kinase (PLK),1 we determined the crystal structures of PLK.AMP-PCP-pyridoxamine, PLK.ADP.PLP, and PLK.ADP complexes. Comparisons of these structures have revealed that PLK exhibits different conformations during its catalytic process. After the binding of AMP-PCP (an analogue that replaced ATP) and pyridoxamine to PLK, this enzyme retains a conformation similar to that of the PLK.ATP complex. The distance between the reacting groups of the two substrates is 5.8 A apart, indicating that the position of ATP is not favorable to spontaneous transfer of its phosphate group. However, the structure of PLK.ADP.PLP complex exhibited significant changes in both the conformation of the enzyme and the location of the ligands at the active site. Therefore, it appears that after binding of both substrates, the enzyme-substrate complex requires changes in the protein structure to enable the transfer of the phosphate group from ATP to vitamin B(6). Furthermore, a conformation of the enzyme-substrate complex before the transition state of the enzymatic reaction was also hypothesized.

Crystal structure of a NO-forming nitrite reductase mutant: an analog of a transition state in enzymatic reaction.

I257E was obtained by site directed mutagenesis of nitrite reductase from Achromobacter cycloclastes. The mutant has no enzyme activity. Its crystal structure determined at 1.65A resolution shows that the side-chain carboxyl group of the mutated residue, Glu257, coordinates with the type 2 copper in the mutant and blocks the contact between the type 2 copper and its solvent channel, indicating that the accessibility of the type 2 copper is essential for maintaining the activity of nitrite reductase. The carboxylate is an analog of the substrate, nitrite, but the distances between the type 2 copper and the two oxygen atoms of the side-chain carboxyl group are reversed in comparison to the binding of nitrite to the native enzyme. In the mutant, both the type 2 copper and the N epsilon atom on the imidazole ring of its coordinated residue His135 move in the substrate binding direction relative to the native enzyme. In addition, an EPR study showed that the type 2 copper in the mutant is in a reduced state. We propose that mutant I257E is in a state corresponding to a transition state in the enzymatic reaction.

Crystallization and preliminary crystallographic studies of pyridoxal kinase from sheep brain.

Pyridoxal kinase (ATP:pyridoxal 5'-phosphotransferase; EC 2.7.1.35) is a key enzyme in the transformation of vitamin B(6) to pyridoxal-5'-phosphate. Pyridoxal-5'-phosphate is the crucial cofactor required by numerous enzymes involved in the metabolism of amino acids and the synthesis of many neurotransmitters. Pyridoxal kinase from sheep brain was crystallized in an orthorhombic form using the hanging-drop vapour-diffusion method with sodium citrate as the precipitant. The crystals belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 59.8, b = 94.4, c = 128.2 A, and diffract to a resolution of 2.1 A. Crystals were transferred into a soaking liquid without citrate and two heavy-atom derivatives were prepared.