Mono-, di- and tri-antennary D-galactose ligands as competitive inhibitors and photoaffinity labels of the hexose transporting system in erythrocytes. A model for the irreversible blocking of receptors in cell membranes.

Starting from pentaerythritol, photolabile mono-, di-, and tri-dentate galactose derivatives as well as their 3H-labelled isotopomers were synthesised. The hydrophilic chains linking the 6 position of D-galactose to pentaerythritol consist of 13 atoms in line. The mono-, di- and tri-dentate compounds, although themselves not transported, inhibit in increasing order 14C-D-galactose transport into erythrocytes.

Selective defucosylation by mercaptolysis. A potential step in analyzing branched oligosaccharides.

A method of stepwise chemical degradation was elaborated on a microgram quantity of 3-O-alpha-L-fucosyllactose. The key step, TiCl4-catalysed dithioacetal formation from the permethylated N-4-nitrophenyl triosylamine (4) was accompanied by quantitative defucosylation. [14C]Acetylation of the dried mercaptalation mixture gave radiolabelled 3,5-di-O-[14C]acetyl-4-O-(2,3,4,6-tetra-O-methyl-beta-D-galactopyranosyl )-2 , 6-di-O-methyl-D-glucose diethyl dithioacetal (7) and 5-O-[14C]acetyl-2,3,4-tri-O-methyl-L-fucose diethyl dithioacetal (8).

Spacer-modified saccharides for the regioselective photoaffinity labelling of the binding site of an immunoglobulin.

The spacer-modified trisaccharides that mimic (1----6)-linked beta-D-galactotetraose (Gal4), namely, O-beta-D-galactopyranosyl-(1----6)-S-beta-D-galactopyranosyl-(1----11)-8 -azi- 6,7,8,9,10-pentadeoxy-11-thio-D-galacto-undecose (12) and O-beta-D-galactopyranosyl-(1----6)-O-beta-D-galactopyranosyl- (1----13)-8-azi-6,7,8,9,10,11,12-heptadeoxy-D-galacto-tri decose (20) were synthesised by coupling disaccharide derivatives with 8-azi-6,7,8,9,10-pentadeoxy-1,2:3,4-di-O-isopropylidene-11-O -tosyl-alpha-D-galacto-undecopyranose (10) and 8-azi-6,7,8,9,10,11,12-heptadeoxy-1,2:3,4-di-O-isopropyli den e-alpha-D-galacto- tridecopyranose (17), respectively. Compounds 12 and 20 had affinities for the combining sites of the antibodies IgA X24 and IgA J 539 similar to those of O-beta-D-galactopyranosyl-(1----6)-O-beta-D- galactopyranosyl-(1----11)-8-azi-6,7,8,9,10-pentadeoxy-D-gal acto-undecose (7) and the native ligand Gal4. Tritium-labelled 7 chemically modified the heavy and light chains of IgA J 539, whereas 8-azi-6,7,8,9,10-pentadeoxy-D-(11-3H)galacto-undecose (5a) reacted only with the heavy chain.

[Transfusion-associated HIV infections in Switzerland 1982-1989].

Up to summer 1987, 19 patients who had acquired HIV infection by blood transfusion had been recorded in Switzerland. In the subsequent period, up to 1989, a further 15 patients with transfusion-associated HIV infection were recorded. In December 1989, 7 of these patients were asymptomatic, 4 had ARC, 5 Aids and 11 had died of Aids.