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排序方式: 共有759条查询结果,搜索用时 15 毫秒
1.
R.E. Jonkers B. Oosterhuis R.J.M. Ten Berge C.J. Van Boxtel 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1982,233(1):249-255
A relatively simple assay with improved reliability and sensitivity for measuring levels of 6-mercaptopurine in human plasma is presented. After extraction of the compound and the added internal standard with phenyl mercury acetate, samples were separated by ion-pair reversed-phase high-performance liquid chromatography. On-line the analytes were oxidized to fluorescent products and detected in a flow-fluorimeter. The within-day coefficient of variation was 3.8% at a concentration of 25 ng/ml. The lower detection limit was 2 ng/ml when 1.0 ml of plasma was used. Mercaptopurine concentration versus time curves of two subjects after a single oral dose of azathioprine are shown. 相似文献
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The effect of copper on the uptake of nitrogen and the tissue contents of inorganic nitrogen, amino acids and proteins were studied in cooper-sensitive Silene vulgaris (Moench) Garcke, grown at different nitrogen sources (NH4
+ or NO3
-). All the toxic copper levels tested, i.e. 4, 8, 16 M Cu2+, strongly inhibited the uptake of nitrogen, especially of NO3
-, and decreased the content of NO3
-, amino acids and proteins. Especially at 4 and 8 M Cu2+, NH4
+ accumulated in the plants, suggesting that the conversion of NH4
- into amino acids was inhibited. 相似文献
7.
C Thoen L Van Hove P Cohen H Slegers 《Biochemical and biophysical research communications》1985,131(1):84-90
In the cytosol of A. salina cryptobiotic gastrulae at least five protein phosphatases active on phosphorylase a have been detected by ion exchange chromatography on DEAE-cellulose. Only two of these enzymes (PP-X and PP-Y) are active in mRNP dephosphorylation. Both enzymes are insensitive to inhibitor-1 and -2 and stimulation of enzymatic activity (2.5-fold with PP-X and 6.5-fold with PP-Y) can be accomplished by ethanol treatment of the native enzymes, or freeze-thawing in the presence of 1.7% (v/v) 2-mercaptoethanol. These properties allow PP-X and PP-Y to be classified as type-2A enzymes according to the nomenclature of Cohen. This paper is the first report of protein phosphatases capable of dephosphorylating mRNP proteins. 相似文献
8.
Hardies SC; Martin SL; Voliva CF; Hutchison CA d; Edgell MH 《Molecular biology and evolution》1986,3(2):109-125
9.
F. J. Van Hemert A. A. W. Ten Have-Opbroek C. J. M. Otto-Verberne 《Histochemistry and cell biology》1986,85(6):497-504
Summary Previous papers reported on a specific antigenic marker for the great alveolar (type-II) cell of the mouse lung and described its recognition by a specific rabbit antiadult mouse lung serum. In the present study light- and electron-microscopical immunohistochemistry on fixed mouse lung sections showed the presence of the marker on the alveolar surface. The antigenic determinants recognized by the antibody were further characterized by immunoblotting and immunoprecipitation studies after in vitro translation of mouse lung messenger RNA.Immunoblots of a surfactant-enriched pellet of a bronchoalveolar lavage fraction of mouse lung showed that the antibody reacted with surfactant-associated proteins having apparent molecular weights of about 27,000, 32,000, and 38,000 daltons in SDS gels. Immunoblots of mouse-lung homogenate revealed the presence of 27,000, 30,000, 39,000, and 41,000 dalton proteins, presumably also surfactant-associated proteins. Immunoprecipitation after in vitro translation of mouse-lung mRNA showed specific reactivity only with a 12,000 dalton polypeptide, a component of the cell marker we were unable to relate to surfactant. Our findings indicate that the 12,000 dalton component of the antigenic marker for the great alveolar cell is a polypeptide whose synthesis is a lung-specific process and that the immunoreaction of the larger and surfactant-associated components is due to post-translational modifications. 相似文献
10.
Mechanism of complement-induced stimulation of prostacyclin production by isolated rabbit peritoneum 总被引:3,自引:0,他引:3
The interaction between the complement system and prostaglandin synthesis has not thoroughly been explored, although both mediators are known to be involved in inflammatory reactions and endotoxic shock. When rabbit peritoneum, a rich source of prostacyclin forming activity was incubated in serum in which the complement system was activated (CVF, LPS, zymosan), the tissue produced significantly more PGI2, when compared with appropriate controls, indicating that by activation of the complement, factors were generated that stimulated PGI2 biosynthesis. Further results indicated that tryptic cleavage products of complement factor C3 and C5 also led to the appearance of PGI2 releasing principles with a molecular weight of about 7000-11000. The stimulation of PGI2 biosynthesis was explained by enhanced release of AA, and not due to increased activity of cyclo-oxygenase or PGI2 synthetase. Our results suggest that complement-derived products may promote the supply of prostaglandins at the site of inflammation. 相似文献