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U Feige

Publications and source records attributed to U Feige.

48 records · Page 3Linked to original sources
PubMed1984

The effect of LDL and modified LDL on macrophage secretion products.

The role that lipid uptake might play in macrophage activation was investigated using mouse peritoneal macrophages in vitro. Incubation with acetylated LDL for 48 hours resulted in a 12 fold increase in cholesterol ester content in macrophages; incubation with oxidized LDL resulted in a 6 fold increase in cholesterol ester, while incubation with native LDL did not result in cholesterol accumulation. Incubation of macrophages with acetylated LDL or oxidized LDL produced no change in macrophage production of plasminogen activator or secretion of interleukin 1 or superoxide anion.

Acetylation↗
PubMed1983

Biosynthesis and transport of lysosomal enzymes in human monocytes and macrophages. Effects of ammonium chloride, zymosan and tunicamycin.

Human monocytes and macrophages synthesize lysosomal enzymes as larger precursors. The polypeptide patterns of several lysosomal-enzyme precursors and their mature forms are similar to those observed in human fibroblasts. Like fibroblasts, the monocytes and macrophages release small amounts of lysosomal-enzyme precursors. The lysosomotropic NH4+ cation enhances this release. In contrast, zymosan, a degranulating agent, causes release of both the mature and the precursor forms of the lysosomal enzymes. Both NH4Cl and zymosan inhibit maturation of the precursors. The fractional amounts of mature cathepsin D and beta-hexosaminidase released in the presence of zymosan are strikingly different. Probably, in the macrophages several lysosomal organelles are packaged with different relative contents of lysosomal enzymes. The transport of the precursors of cathepsin D into lysosomes is inhibited by tunicamycin. Therefore oligosaccharide side chains are likely to function as signals in packaging of lysosomal enzymes in macrophages also.

Ammonium Chloride↗
PubMed1983

Characterization of human lymphocyte derived chemotactic factors for mononuclear phagocytes--I. Production and detection.

Human peripheral blood mononuclear cells were isolated on a large scale by leukapheresis of either individual donors or pooled cell concentrates supplied by a local blood bank. Optimal conditions with respect to cell density, lectin (soluble and insoluble Concanavalin A; phytohemagglutinin) concentration and culture time were established for monocyte chemotactic factor (LMCF) production. LMCF was assayed on highly purified human monocytes/macrophages which had been kept in culture up to 4 days for optimal expression of response to LMCF. Chemotaxis assays were performed in a novel type multichamber assembly and migrated cells were enumerated by enzyme-linked immunosorbent assay. Based on the described methodology it is possible to produce litre quantities of LMCF and assay large numbers of samples both of which are prerequisites for chemical and functional characterizations of LMCF.

Cells, Cultured↗
PubMed1982

Purification of human blood monocytes by hypotonic density gradient centrifugation in Percoll.

Leukocyte cell concentrates, obtained by continuous flow leukapheresis from single donors, were separated on a continuous hypotonic (260 mosM) Percoll gradient. On average, 86% of monocytes were recovered in a sharp band at a purity of up to 91% (average 76%). By this procedure 1-2 X 10(9) monocytes may be obtained from an individual donor. Hypotonic gradient purification, as compared with isotonic (295 mosM) conditions, proved superior with regard to capacity, speed of performance, yield and monocyte purity.

Cell Separation↗
PubMed1982

Use of a multiwell assembly for chemotaxis and evaluation by enzyme-linked immunosorbent assay (ELISA).

A multiwell chamber assembly for chemotaxis tests was designed, which integrates the established microtiter system. A microtiter plate is covered with a plastic plate containing up to 96 holes of the diameter of the microtiter wells. Between the plates, a Nucleopore filter sheet (5 micron) and a silicon rubber gasket is placed. As a model system, human monocytes and lymphocyte-derived chemotactic factors were used. As it was observed that monocytes migrate through the membrane and settle on the bottom of the microtiter wells, an ELISA was adapted for quantitation of cells. After washing and incubation with a xenoantiserum against human monocytes, the bound antibody was quantitated using protein-A-conjugated alkaline phosphatase and p-nitrophenyl phosphate as detection system. The plates were read in a multichannel photometer. Cell numbers were determined directly from a calibration curve established before with varying numbers of monocytes. Current experience allows the following conclusions: The chemotaxis test in microtiter plates is simpler, faster and uses less material than conventional Boyden chambers. Evaluation by ELISA is much faster and more accurate than by microscopy.

Animals↗
PubMed1981

Structure of the heptose region of lipopolysaccharies from Rhodospirillum tenue.

There is a common structure (core region) in the lipopolysaccharides of Rhodospirillum tenue. It is composed of a branched trisaccharide of L-glycero-D-mannoheptose (and of 2-keto-3-deoxyoctonate), as revealed by methylation analyses of degraded polysaccharides of four different R. tenue strains. The structure is similar or might even be identical to the inner core of enterobacterial O antigens. In addition, each of the four R. tenue lipopolysaccharides contains a strain-specific region that consists of heptose(s) (L-glycero-D-mannoheptose or D-glycero-D-mannoheptose or both) or hexoses. There is a partial substitution of the core region and the strain-specific region by phosphorus, showing microheterogeneity.

Chemical Phenomena↗
PubMed1981

Phosphate localization in carbohydrates - a study on enterobacterial lipopolysaccharides.

The localization of the phosphate substituents in the core oligosaccharide of the lipopolysaccharides of Enterobacteriaceae has been reported for Salmonella minnesota and Escherichia coli B only. In these cases the localizations were done by a beta-elimination reaction in mild alkaline solution after periodate oxidation. We report now on a method generally applicable on carbohydrates. The localization of phosphate groups and the extent of substitution with phosphate residues in carbohydrates can be determined by the following reaction sequence: methylation, dephosphorylation, and reetherification (labelling) with C2H3J or C2H5J followed by derivatizing to partially methylated alditol acetates and analysis by combined gas liquid chromatography/mass spectrometry. The results presented here are obtained by application of this method to isolated core oligosaccharides of lipopolysaccharides from E. coli C23.1, E. coli C71, E. coli F2515, and P. mirabilis R4/O 28. Phosphate is localized at C-4 of the chain heptoses in the lipopolysaccharides of E. coli C and E. coli R4, and at C-7 of the branching heptose in the lipopolysaccharide of P. mirabilis R4/O 28.

Chemical Phenomena↗
PubMed1981

The lipopolysaccharide of escherichia coli C- studies on the anomeric configurations of the hexoses in the R1 core.

Lipopolysaccharide from E, coli C as well as lipopolysaccharides from submutants of E. coli with incomplete core structures in their lipopolysaccharides were isolated and quantitatively analyzed. Core oligosaccharides were isolated from lipopolysaccharides by acetic acid degradation and were purified by gel chromatography. The difference in molecular rotations of the core oligosaccharides from E. coli C and 6 submutants thereof with incomplete core structure were correlated to the differences in sugar compositions. The anomeric configurations have been deducted from the high or low contribution of each individual sugar to the molecular rotation of the core oligosaccharide from E. coli C. The primary structure of the hexose region of the lipopolysaccharide from E. coli C is primary structure of the hexose region of the lipopolysaccharide from E. coli C is, see formula in text. The anomeric configurations of glucoses I, II, and III were confirmed by precipitation reactions of alkali treated lipopolysaccharides from E. coli C, C23. 1, and C21 with Concanavalin A. The alpha-anomeric configurations of both the galactoses were confirmed by degradation studies with alpha-galactosidase (E.C.3.2.1.22) from green coffee beans with the isolated and purified core oligosaccharide from E. coli C71.

Carbohydrate Conformation↗
PubMed1980

Structural studies on the glucose-heptose region of the Proteus mirabilis R core.

Methylation analysis of the core oligosaccharide of the Proteus mirabilis mutant R4 (derived from serotype 028 was carried out in order to obtain information on the internal (glucose-heptose) region of the P. mirabilis R core. The isolated core oligosaccharide was composed of glucose, L-glycero-D-manno-heptose, 3-deoxy-D-manno-octulosonic acid (dOclA) and phosphorus in a molar ratio of about 1:2:1:1.4. It was methylated either directly or after dephosphorylation. To localize the position of the phosphate substituents, the permethylated product was dephosphorylated with hydrogen fluoride and the oligosaccharide obtained was remethylated using C2H3I. Location of phosphate at C-7 of the terminal heptose was shown by isolation of the sugar phosphate from partial hydrolysates and gas-liquid chromatography/mass spectrometry of the permethylated product. Combining the data of the methylation analysis with the data of an NMR study allows one to formulate the structure of the core oligosaccharide as folllows: (formula: see text).

Carbohydrate Conformation↗
PubMed1975

Escherichia coli capsule bacteriophages. VII. Bacteriophage 29-host capsular polysaccharide interactions.

Different interactions between particles of Escherichia coli capsule bacteriophage 29 and its receptor, the E. coli serotype 29 capsular polysaccharide have been studied. The inactivation of phage 29 (8 x 10(3) PFU/ml) by isolated host capsular glycan was found to be physiologically insignificant (50% inactivation dose equals 100 mug after 1 h at 37 C). No adsorption (less than 2 x 10(4) PFU/mug) of the viruses to K29 polysaccharide-coated erythroyctes (at 0 or 37 C) was observed either. The phage particles were, however, found to catalyze the hydrolysis of beta-D-glucosido-(1leads to 3)-D-glucuronic acid bonds (arrow) in the receptor polymer, leading, ultimately, to the formation of a mixture of K29 hexasaccharide (one repeating unit), dodecasaccharide, and octadecasaccharide: (see article). Testing derivatives of K29 polysaccharide, as well as 82 heterologous bacterial (mainly Enteriobactericeae) capsular glycans, the viral glycanase was found to be highly specific; in accordance with the host range of phage 29, only one enzymatic cross-reaction (with the Klebsiella K31 polysaccharide) was observed. These and previous results, as well as the electron optical findings of M. E. Bayer and H. Thurow (submitted for publication), are discussed in terms of a unifying mechanism of phage 29-host capsule interaction. We propose that the viruses penetrate the capsules by means of their spike-associated glycanase activity, which leads them along capsular polysaccharide strands to membrane-cell wall adhesions where ejection of the viral genomes occurs.

Adsorption↗