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Biomedical subjects

G Till

Publications and source records attributed to G Till.

At least 19 recordsLinked to original sources
PubMed1992

Secondary metabolites by chemical screening. 8. Decarestrictines, a new family of inhibitors of cholesterol biosynthesis from Penicillium. I. Strain description, fermentation, isolation and properties.

A family of new 10-membered lactones was detected by chemical screening. Taxonomic studies and fermentation conditions of the producing organisms, which belong to the species Penicillium simplicissimum and Penicillium corylophilum, are presented. The isolation as well as physico-chemical data of the new compounds named decarestrictines A to D are reported. In vitro testing using the HEP-G2 cell assay showed the decarestrictines to be inhibitors of cholesterol biosynthesis, which could be confirmed in vivo. In addition to the decarestrictines from P. corylophilum epoxyagroclavine-I (1) was isolated.

Animals↗
PubMed1981

[Prevention of antibody mediated dextran side effects by hapten inhibition in dogs (author's transl)].

The effectiveness of low molecular dextran (dextran 1) in preventing antibody mediated dextran side effects (hapten inhibition) was investigated in immunized dogs. After injection of clinical dextran (dextran 60) a rapid fall of systolic blood pressure and a decrease of leucocytes, thrombocytes and haemolytic complement activity was noted. The protective effect of a dextran 1 preinjection was clearly demonstrated; in contrast the built-in hapten injection (dextran + hapten together) was ineffective.

Animals↗
PubMed1980

Migration of leukocytes into filters coated homogeneously with immune complexes, antigens, lectins or tripeptides.

Cellulose nitrate filters were incubated in solutions of albumin, a chemotactically active tripeptide (f-Met-Leu-Phe), immune complexes or lectins and afterwards washed with buffer. They showed a dose-dependent increased leukocyte migration, when tested in typical Boyden chambers in comparison to filters treated only with buffer. The tripeptide, the immune complexes and the lectins were stimulatory at very low concentrations and acted inhibitory at high concentrations. Treating filters with formaldehyde or glutardialdehyde had no clear stimulatory effect. These findings extend earlier observations obtained with casein. They show that cells move very effectively on solid substrata in the absence of concentration gradients.

Animals↗
PubMed1980

Induction of prostaglandin E release from macrophages by colchicine.

Rat peritoneal macrophages released high amounts of prostaglandin E (PGE) when treated in vitro with 10(-7) to 10(-4) M colchicine. PGE production occurred after a lag period of 4 hr and proceeded at a constant rate for more than 24 hr. Lymphocytes could not be stimulated to PGE release by colchicine. Disaggregation of microtubules appeared to be an essential event, since lumicolchicine was inactive and addition of heavy water (D2O) abolished colchicine-induced PGE formation. Cytochalasin B (5 microgram/ ml) did not interfere with PGE production by colchicine during the initial 12 hr, but thereafter it gave rise to an activity capable of degrading or converting newly synthesized PGE. Although details of the mechanisms by which colchicine in association with disrupted microtubules may induce PGE release remain unclear, these observations suggest that components of the cytoskeleton may efficiently influence the biosynthesis of prostaglandins.

Animals↗
PubMed1978

Activation of complement by radiographic contrast media: generation of chemotactic and anaphylatoxin activities.

Iodinated radiographic contrast media such as methylglucamine diatrizoate and sodium ioglycamate activate serum complement in vitro. This was shown by a dose-, time-, and temperature-dependent decrease of total hemolytic complement activity in normal human serum, consumption of C4 and C6 activity, conversion of C3 to C3b, and generation of C5-derived chemotactic and smooth muscle contracting activity. Complement activation was achieved even in sera depleted of immunoglobulin and properdin, which may indicate that contrast media induce complement activation by mechanisms different from the classical or alternative pathway.

Anaphylatoxins↗
PubMed1978

Chemotactic activity of lectins in vitro.

The effects of concanavalin A (Con A) and leucoagglutinin (LA) on the locomotor response of phagocytes have been studied in vitro. At concentrations of 1 to 4 microgram/mol, Con A and LA induced maximal chemokinesis and chemotaxis of monocytes, macrophages and, to a lesser degree, also of neutrophils. The lectin-induced locomotion was accompanied by membrane alterations and metabolic changes, as shown by an increase of the 3H-uridine uptake and a rise of the hexose monophosphate shunt activity. The chemotactic activity of Con A was inhibited by alpha-methyl mannoside (50 mM) or by pretreatment of the cells with trypsin. These data indicate that lectins such as Con A induce chemotaxis by a specific binding to receptors of the cell membrane. It is suggested that bivalent ligand binding is required as a signal to elicit chemotactic locomotion.

Agglutinins↗