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- Szymanski, J. J., et al.
(författare)
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MEGA : A search for the decay mu –> e gamma
- 1994
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Ingår i: Intersections between particle and nuclear physics. Proceedings, 5th Conference, St. Petersburg, USA, May 31-June 6, 1994. ; , s. 789-792
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Konferensbidrag (refereegranskat)
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| 2. |
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| 3. |
- Birnir, Bryndis, et al.
(författare)
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Expression and characterization of the intestinal Na+/glucose cotransporter in COS-7 cells.
- 1990
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Ingår i: Biochimica et Biophysica Acta. - 0006-3002 .- 1878-2434. ; 1048:1, s. 100-4
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Tidskriftsartikel (refereegranskat)abstract
- Cells derived from the simian kidney, COS-7 cells, were transfected with a eucaryotic expression vector (pEUK-C1) containing the clone for the rabbit intestinal Na+/glucose cotransporter. Expression was monitored after transfection with lipofectin by measuring the initial rate of alpha-methylglucopyranoside (MeGlc) uptake. Cells transfected with vector containing the cDNA for the Na+/glucose cotransporter expressed Na(+)-dependent MeGlc transport. Neither control cells nor cells transfected with vector lacking cloned cDNA expressed the cotransporter. Na(+)-dependent MeGlc uptake into transfected cells was saturable (Km 150 microM), phlorizin-sensitive (Ki 11 microM), and inhibited by sugar analogs (D-glucose greater than MeGlc greater than D-galactose greater than 3-O-methyl-D-glucoside greater than D-allose much greater than L-glucose). Europium was able to mimic Na+ in driving MeGIC uptake. Finally, tunicamycin, an inhibitor of asparagine-linked glycosylation, inhibited the expression of Na(+)-dependent MeGlc transport 80%. We conclude that the rabbit intestinal Na+/glucose cotransporter expressed in COS-7 cell exhibits very similar kinetic properties to that in the native brush border and to that expressed in Xenopus oocytes. In addition, N-linked glycosylation appears to be important for functional expression of this membrane protein.
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| 4. |
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| 5. |
- Mircheff, A K, et al.
(författare)
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Class II antigen expression by lacrimal epithelial cells. An updated working hypothesis for antigen presentation by epithelial cells
- 1991
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Ingår i: Investigative Ophthalmology and Visual Science. - 0146-0404 .- 1552-5783. ; 32:8, s. 2302-2310
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Tidskriftsartikel (refereegranskat)abstract
- It has been suggested that aberrant expression of Class II histocompatibility antigens (HLA) is involvedin T cell activation and leads to autoimmunity. Although Class II antigen expression was foundin various nonlymphoid tissues, including salivary glands, its expression on lacrimal epithelial cells hasnot been reported. In this study, 12 cadaver lacrimal glands were analyzed for HLA-DR and for thenumbers and distributions of T suppressor cells (Ts), T helper cells (Th), B cells, and macrophages.None of these cases exhibited the high numbers of inflammatory cells, tissue damage, and fibrosischaracteristic of Sjogren's syndrome. The HLA-DR-positive epithelial cells were detected in ten cases;they represented from less than 1% to more than 70% of the epithelial cells. In these ten positive cases,there were greater numbers of T cells per millimeter squared (229 ± 94 [mean ± the standard error ofthe mean]) than in the two HLA-DR-negative cases (37 ± 1 [mean ± range]). Three lacrimal glandspecimens tested were negative for immunoglobulin (Ig) G-bearing B cells, and two of the three specimenstested had IgA-bearing cells. Acinar cells were isolated from rat and rabbit lacrimal glands andcultured overnight in serum-free media supplemented with several potential mediators of Class IIantigen expression: interferon-7, carbachol, or isoproterenol. Freshly isolated cells did not expressClass II antigens at detectable levels, but in most experiments, they began to express the antigen evenin the absence of putative mediators. In light of results from recent studies of antigen presentation andepithelial cell membrane dynamics, these findings suggest a hypothesis in which Class II antigen-expressingepithelial cells present antigenic peptides that are generated in the intracellular compartmentsin communication with the basal-lateral membrane assembly and recycling pathway.
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