Rapid and simultaneous determination of two immunosup-pressants in whole blood by high performance liquid chroma-tography

Cyclosporine A and sirolimus are immunosuppressants that are widely used in many organ transplantation procedures. They exhibit some complementary mechanisms of action and interact synergistically when used together. However, they are critical⁃dose drugs and have a narrow therapeutic index. They provide the desired therapeutic effect with acceptable tolerability only within a specific range of blood concentrations. Therefore, the rapid and simultaneous detection of the concentrations of cyclosporine A and sirolimus in whole blood could provide valuable information on planning medicine administration after organ transplantations. In this study, firstly, the chromatographic behaviors of cyclosporine A and sirolimus on a biological liquid chromatography (BioLC)column and traditional liquid chromatography (TraLC)columns were investigated systematically under the same chromatographic conditions. The results suggested that the peak height and peak width of cyclosporine A and sirolimus on the BioLC column, ZORBAX 300SB C8 (250 mm X 4.6 mm, 5.0 μ m), were the highest and narrowest, respectively. The number of theoretical plates of cyclosporine A and sirolimus on the ZORBAX 300SB C8 column increased significantly when the volume ratio of acetonitrile in the mobile phases was greater than 70%. Their retention time on the BioLC and TraLC columns was negligibly affected by the use of formic acid and trifluoroacetic acid as the mobile phases. In the range of the experimental column temperature, the number of theoretical plates of cyclosporine A and sirolimus on the ZORBAX 300SB C8 column was significantly higher than that on the two TraLC columns. Furthermore, the relationship between the retention factor and column temperature of cyclosporine A on the ZORBAX 300SB C8 column was different from that on the two TraLC columns. A sample of whole blood with a volume of 50 μL was prepared by protein precipitation with 1 mol/L sodium hydroxide and then extracted into 500 μL of ether⁃methanol (95:5, v/v). After centrifugation at 14.000 r/min for 10 min, the organic layer was removed and evaporated under a stream of nitrogen at 50 ℃. The residue was then reconstituted in 200 μL of methanol for use. Cyclosporin A and sirolimus were separated through isocratic elution on the ZORBAX 300SB C8 column

Characterization by Suppression Subtractive Hybridization of Transcripts That Are Differentially Expressed in Leaves of Anthracnose-Resistant Ramie Cultivar

For the purpose of screening putative anthracnose resistance-related genes of ramie (Boehmeria nivea L. Gaud), a cDNA library was constructed by suppression subtractive hybridization using anthracnose-resistant cultivar Huazhu no. 4. The cDNAs from Huazhu no. 4, which were infected with Colletotrichum gloeosporioides, were used as the tester and cDNAs from uninfected Huazhu no. 4 as the driver. Sequencing analysis and homology searching showed that these clones represented 132 single genes, which were assigned to functional categories, including 14 putative cellular functions, according to categories established for Arabidopsis. These 132 genes included 35 disease resistance and stress tolerance-related genes including putative heat-shock protein 90, metallothionein, PR-1.2 protein, catalase gene, WRKY family genes, and proteinase inhibitor-like protein. Partial disease-related genes were further analyzed by reverse transcription PCR and RNA gel blot. These expressed sequence tags are the first anthracnose resistance-related expressed sequence tags reported in ramie

Effects of the Inductive Charging on the Electrification and Lightning Discharges in Thunderstorms

A two-dimensional cloud model with electrification and lightning processes is used to investigate the role of inductive charge separation in thunderstorm clouds. For the same dynamic and microphysical evolution, four cases that the same non-inductive charging parameterization is combined with different inductive charging process are compared. Non-inductive charge separation alone is found to be sufficient to produce a dipolar charge structure. Intracloud (IC) and positive cloud-to-ground (+CG) flashes are initiated between a main negative charge region and an upper positive charge region. The inductive charging process between graupel and cloud droplets exhibits a normal tripole charge structure, consisting of a lower positive charge region under the main negative charge region. In the simulated tripole structure, negative cloud-to-ground (-CG) flashes are initiated between the main negative and lower positive charge regions. In addition, inductive charge separation between the graupel and ice crystal is found to be capable of producing strong charge separation in a dipole charge structure. Tests with inductive graupel-ice crystals process produce more flashes than that in the other cases

Acetonitrile­triaqua­[3-eth­oxy-1,8-(3,6,9-trioxaundecane-1,11-diyldi­oxy)-9H-xanthen-9-one]terbium(III) tris­(perchlorate)

In the title compound, [Tb(CH3CN)(C23H26O8)(H2O)3](ClO4)3, the Tb3+ atom is eight-coordinated by one N atom of an acetonitrile molecule, three water O atoms and four ligand O atoms. The Tb3+ atom is located on one side of the macrocycle and the carbonyl oxygen coordinated to the terbium [Tb1—O1= 2.210 (3) Å] is bent out of the xanthone plane by 0.514 (3) Å. The geometry around terbium is a distorted two-capped trigonal prism