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991.
Chechlińska M Duma A Swierkowska K Kamińska J Steffen J 《Cellular & molecular biology letters》2004,9(1):69-81
We have shown that the sera of lung cancer patients affect the response of ConA-stimulated normal peripheral blood mononuclear cells by decreasing the expression of IL-2Ralpha and inhibiting the release of IL-1beta and IL-2. A tendency to enhance the release of IL-6 was also observed. We conclude that an imbalance in the Th1/Th2 cytokine response, typical for cancer patients, may at least partly be related to soluble factors circulating in the patients' blood. We discuss a putative role of serum IL-10, IL-1ra, and soluble IL-2Ralpha in the effects observed. 相似文献
992.
993.
Johansson L Chen C Thorell JO Fredriksson A Stone-Elander S Gafvelin G Arnér ES 《Nature methods》2004,1(1):61-66
Selenium is essential to human life and occurs in selenoproteins as selenocysteine (Sec), the 21st amino acid. The selenium atom endows selenocysteine with unique biochemical properties, including a low pK(a) and a high reactivity with many electrophilic agents. Here we describe the introduction of selenocysteine into recombinant non-selenoproteins produced in Escherichia coli, as part of a small tetrapeptide motif at the C terminus. This selenocysteine-containing motif could subsequently be used as a protein tag for purification of the recombinant protein, selenolate-targeted labeling with fluorescent compounds or radiolabeling with either gamma-emitting (75)Se or short-lived positron emitters such as (11)C. The results presented here thus show how a wide range of biotechnological applications can be developed starting from the insertion of selenocysteine into proteins. 相似文献
994.
995.
996.
Bilia AR Scalise L Bergonzi MC Vincieri FF 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2004,812(1-2):203-214
The chemical analysis and quality control of both Piper methysticum G. Forster (kava-kava) and extracts obtained by aqueous acetone or aqueous methanol as well as supercritical fluid extraction are reviewed. In the last two decades various procedures concerning the separation and detection of kavalactones have been routinely carried out by gas chromatography (without previous derivatization of kavalactones) and high performance liquid chromatography but most of them are not validated or only partially validated. Recently, analyses by supercritical fluid chromatography and micellar electrokinetic chromatography have also been reported. Both gas chromatography and high performance liquid chromatography can be used for the analysis of kavalactones with some advantages and disadvantages for each method. Using gas chromatography analysis, methysticin and yangonin, which are two of the major components, are generally not separated. In addition, the high temperature of the injection port caused the decomposition of methysticin. Concerning high performance liquid chromatography analyses, the reversed-phase is generally better because highly reproducible with a very low detection limit for all compounds even if the quantitative analysis of the kavalactones by liquid chromatography needs to be carried out in the absence of light to prevent the cis/trans isomerisation of yangonin. 相似文献
997.
Waksmundzka-Hajnos M Petruczynik A Dragan A Wianowska D Dawidowicz AL Sowa I 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2004,800(1-2):181-187
Analysis of plant material is an important task in chemotaxonomical investigations, in search of plants with pharmacological activity or in standardisation of plant drugs. The choice of optimal conditions for the analysis of plant material and effect of extraction method on the yield of furanocoumarins from Pastinaca sativa fruits were examined. The following extraction methods were used in experiments: exhaustive extraction in Soxhlet apparatus, ultrasonification (USAE) at 25 and 60 degrees C, microwave-assisted solvent extraction in open and closed system (MASE) and accelerated solvent extraction (ASE). In most cases, the yield of furanocoumarins was highest by use of ASE method as well as by ultrasonification at 60 degrees C. 相似文献
998.
Krzek J Czekaj JS Rzeszutko W Jończyk A 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2004,803(2):191-200
The conditions for separation, identification and quantitative determination of epimers 22R and 22S of budesonide by capillary gas chromatography (GC) with FID detection and two various sample injection methods, namely split-splitless and cool on-column, were established. In analysis helium as carrier gas and Rtx-5 capillary column of 7 m in length along with stationary phase Crossbond 5% diphenyl-95% dimethyl polysiloxane were used. The individual epimers were identified under specified conditions by using standard samples of different declared concentration of each epimer under investigation: (1) 51.2% of epimer 22R and 47.3% of epimer 22S, and (2) 95.1% of 22R and 4.4% of 22S, as well as Pulmicort, a preparation containing micronized budesonide as an active substance. It seems that good parameters of preliminary validation achieved by the proposed methods can confirm its suitability for quantitative analysis purpose. The retention times obtained for epimers 22R and 22S, depending on injection technique are about 7.7 and. 8.3 min for split and, approx. 10.3 and 10.9 min for cool on-column. The limits of detection and quantitation are 5.7 and 6.2 ng, for 22R respectively, and 4.3 and 4.8 ng for 22S. The linearity is maintained for concentrations ranging from 0.01 to 0.20 mg/ml. The quantitative analysis features of repeatability, high precision and accuracy confirmed by the obtained results and its statistical evaluation. 相似文献
999.
Differential phosphoproteome profiling by affinity capture and tandem matrix-assisted laser desorption/ionization mass spectrometry 总被引:2,自引:0,他引:2
Protein phosphorylation is a ubiquitous post-translational modification that affects a significant subset of the proteome and plays an especially important role in signal transduction and cell cycle control in eukaryotic organisms. Recently developed methods that couple multidimensional liquid chromatography to electrospray mass spectrometers can be used to analyze entire phosphoproteomes. However, they require considerable investments and technical skills that are only available in a few highly specialized laboratories. These methods also appear to be biased. Statistical analyses show that peptides from abundant proteins and multiply phosphorylated peptides are disproportionately identified. We describe an economic alternative that utilizes a phospho-affinity step to isolate the intact phosphoproteins. These are subsequently characterized by electrophoresis and identified by direct de novo sequencing using tandem mass spectrometry. We applied this technique to probe signal-induced changes in the phosphoproteome of human U937 cells, and found that the pools of two cancer-related phosphoproteins implicated in intracellular hormones signaling are dramatically altered in the course of monocyte to macrophage differentiation. 相似文献
1000.
Carraro DM Camargo AA Salim AC Gonzaga L Costa GC Vasconcelos AT Simpson AJ 《Genetics and molecular research : GMR》2004,3(1):53-63
In the finishing phase of the Chromobacterium violaceum genome project, the shotgun sequences were assembled into 57 contigs that were then organized into 19 scaffolds, using the information from shotgun and cosmid clones. Among the 38 ends resulting from the 19 scaffolds, 10 ended with sequences corresponding to rRNA genes (seven ended with the 5S rRNA gene and three ended with the 16S rRNA gene). The 28 non-ribosomal ends were extended using the PCR-assisted contig extension (PACE) methodology, which immediately closed 15 real gaps. We then applied PACE to the 16S rRNA gene containing ends, resulting in eight different sequences that were correctly assembled within the C. violaceum genome by combinatory PCR strategy, with primers derived from the non-repetitive genomic region flanking the 16S and 5S rRNA gene. An oriented combinatory PCR was used to correctly position the two versions (copy A and copy B, which differ by the presence or absence of a 100-bp insert); it revealed six copies corresponding to copy A, and two to copy B. We estimate that the use of PACE, followed by combinatory PCR, accelerated the finishing phase of the C. violaceum genome project by at least 40%. 相似文献