Gene/Protein Disease Symptom Drug Enzyme Compound
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 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A unique immunoliposome has been developed as a drug delivery vehicle for immunotherapy. Human recombinant interleukin-2 (IL-2) has been chemically coupled to the external surface of small unilamellar vesicles (SUVs) containing methotrexate as a candidate immunosuppresive agent in order to specifically direct the drug-bearing liposome to activated T-cells expressing the high affinity IL-2 receptor. This drug delivery system is designed to deliver an immunosuppressive agent to those cells that actively participate in disorders such as graft rejection without delivering an effective but potentially toxic drug to all cells of the immune system as well as other healthy tissues. IL-2 was chemically modified with succinimidyl 4-[p-maleidophenyl butyrate](SMPB) while the receptor binding domain on IL-2 was protected by monoclonal anti-IL-2 bound to Protein A-Silica Gel. The antibody recognizes the receptor binding domain of the IL-2 molecule. The IL-2 was derivatized with S-succinimidyl-S-thioacetate (SATA) in order to add an acetyl thioester group to the lipid and create the complex. The derivatized lipid (SATA-PE) was then part of the liposome formulation containing DSPC:cholesterol: SATA-PE at a mole ratio of 1.5:1.0:0.26. SMPB-IL-2 was covalently coupled to the external surface of the SUV after deacetylation of the thioester moiety at pH 7.4 in PBS. Liposomes prepared by sonication or extrusion had an average diameter of 46-50 nm. SUV-IL-2 bound to the high affinity IL-2 receptor as measured by competitive binding assays and Scatchard analysis using 111InCl2-loaded liposomes The preparation exhibited a binding constant of 30 pM, consistent with values for free IL-2 cited in the literature. SUV IL-2 could be used as the sole source of IL-2 for the murine CTLL-2 T-cell line or for human mitogen-activated PBLs. The presence of IL-2 coupled to the surface was absolutely required for delivery of the drug to the cell. When methotrexate was encapsulated within the internal aqueous space, receptor-mediated endocytosis led to the inhibition of proliferation due to delivery of MTX to the cytoplasm of the cell. More than 90% of the methotrexate was retained within the liposome during storage over a 24-h period at 4 degrees C. This immunoliposome represents a new class of cell specific immunoliposomes whose entry into the cell is controlled by a cell surface receptor.
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PMID:The development of IL-2 conjugated liposomes for therapeutic purposes. 954 72

A novel analytical method for analysis of microbial quinones in activated sludge sample was developed with improved reliability compared to the conventional method. The operating conditions for the extraction of quinones from activated sludge sample with a methanol-chloroform mixture and hexane were optimized. A solid phase extraction method using the Sep-Pak Plus Silica, a small column packed with silica gel, was employed for the purification and separation of quinones instead of column chromatography and thin layer column chromatography used in the conventional method. The analytical operation was simplified and the analytical time was shortened by a half or two-thirds of that required for the conventional method. The recoveries of quinones were markedly increased from 30-60% with the conventional method to as high as 90-101% with the improved method, demonstrating that the reliability of the analytical results of the improved method is significantly higher than that of the conventional method. The quinone content value obtained using the improved method was twice as high as that obtained using the conventional method for the same activated sludge sample, but the quinone profiles expressed as the mole fraction of each quinone type were the same for each method.
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PMID:Development of a novel solid phase extraction method for the analysis of bacterial quinones in activated sludge with a higher reliability. 1623 85

A method for determining approximately 0.2 microg/g or more of germanium in ores, concentrates, zinc-processing products and related materials is described. The sample is decomposed by fusion with sodium peroxide and the cooled melt is dissolved in dilute sulphuric acid. Silica, if > 50 mg, is removed by volatilization with hydrofluoric acid. Germanium is separated from sodium salts by co-precipitation with hydrous ferric oxide, the precipitate is dissolved in 3M hydrochloric acid and germanium is subsequently separated from iron(III) and other co-precipitated elements by a single heptane extraction of germanium tetrachloride from approximately 9.4M hydrochloric acid. The extract is washed with 12M hydrochloric acid to remove residual iron(III), then germanium is stripped with water and determined spectrophotometrically with phenylfluorone in a 1.4M hydrochloric acid-0.002M cetyltrimethylammonium bromide medium in the presence of ascorbic acid as a reductant for co-extracted chlorine. The apparent molar absorptivity of the complex is 1.71 x 10(4) l.mole(-1).mm(-1) at 507 nm, the wavelength of maximum absorption. Up to 5 mg of tin(IV), 10 mg of antimony(V) and tungsten(VI) and approximately 50 mg of silica do not interfere. Germanium values are given for some Canadian certified reference ores, concentrates and iron-formation samples and for a metallurgical dust.
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PMID:Spectrophotometric determination of germanium in ores, concentrates, zinc-processing products and related materials with phenylfluorone and cetyltrimethylammonium bromide after separation by iron collection and heptane extraction of germanium tetrachloride. 1896 6

Iron oxides catalyze the conversion of hydrogen peroxide (H(2)O(2)) into oxidants capable of transforming recalcitrant contaminants. Unfortunately, the process is relatively inefficient at circumneutral pH values because of competing reactions that decompose H(2)O(2) without producing oxidants. Silica- and alumina-containing iron oxides prepared by sol-gel processing of aqueous solutions containing Fe(ClO(4))(3), AlCl(3), and tetraethyl orthosilicate efficiently catalyzed the decomposition of H(2)O(2) into oxidants capable of transforming phenol at circumneutral pH values. Relative to hematite, goethite, and amorphous FeOOH, the silica-iron oxide catalyst exhibited a stoichiometric efficiency, defined as the number of moles of phenol transformed per mole of H(2)O(2) consumed, which was 10-40 times higher than that of the iron oxides. The silica-alumina-iron oxide catalyst had a stoichiometric efficiency that was 50-80 times higher than that of the iron oxides. The significant enhancement in oxidant production is attributable to the interaction of Fe with Al and Si in the mixed oxides, which alters the surface redox processes, favoring the production of strong oxidants during H(2)O(2) decomposition.
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PMID:A silica-supported iron oxide catalyst capable of activating hydrogen peroxide at neutral pH values. 1994 68