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Biomedical subjects

M Lober

Publications and source records attributed to M Lober.

At least 37 records · Page 2Linked to original sources
PubMed1982

[Isolation of an alpha-globulin from rabbit serum responsible for a cobalt(II) ion-induced change in conformation of fibrinogen].

A change in conformation of fibrinogen, caused by cobaltous ions after parenteral application or incubation of plasma, is dependent on the presence of species specific plasma proteins. These proteins, which can be found only in some animals, have not yet been identified. An glycoprotein, responsible for the cobalt effect, was isolated from rabbit serum. It migrates immunoelectrophoretically as an alpha-globulin. In the SDS electrophoresis it was shown to migrate in front of albumin. The actions of this protein, induced by cobaltous ions, could be inhibited by complexing and SH groups alkylating compounds.

Alpha-Globulins↗
PubMed1982

[Production and characterization of antisera against O,O-diethyl-O-(p-nitrophenyl)-phosphate (paraoxon)].

Methods for the production of antibodies against Paraoxon in rabbits are described. The highest-titre antisera were produced with conjugates containing a succinyl spacer group with a degree of derivatisation between 8 and 12 haptens per albumin molecule. The antibody response was tested by immunoprecipitation in agar gel with a hapten-rabbit-albumin-complex and by a radioimmunoassay. The synthesis of 125I labelled tracers is reported. The most potent antisera bound 50% of the radioactive tracer after 1:10(5) dilution and showed apparent affinity constants of 10(6) to 10(7) M-1 for Paraoxon. Compared to Paraoxon these antisera possessed cross reactivities with Parathion of 8.8 to 13.8%, with Methylparathion of 0.35 to 0.82%, and with Dimethoat of 0.0006 to 0.0012%.

Animals↗
PubMed1980

[Qualitative changes in plasma fibrinogen in irradiated rabbits].

Plasma fibrinogens of sublethally irradiated rabbits (8 Gy X-ray irradiation) were isolated by affinity chromatography on fibrin monomer Sepharose and characterised by polyacrylamide gel electrophoresis with sodium dodecylsulfate before and after reduction with 2-mercaptoethanol. Only a small increase of fibrinogen degradation was mainly observed in early phases after irradiation. Fibrin monomer complexes were precipitated together with fibrinogen by 2,5 mol beta-alanine/l. The content of monomer complexes in the precipitate was estimated using Sepharose 6B gel chromatography. Evidence for an increased formation of monomers in the blood could not be obtained. Therefore, proteolytic changes of fibrinogen do not play a role for inducing a hemorrhagic disorder after sublethal X-ray irradiation in rabbits.

Animals↗
PubMed1977

[Electrophoretic patterns of differently prepared fibrinogen subunits in sodium dodecyl sulfate containing polyacrylamide gels].

The electrophoretic behaviour of mercapto, carboxamidomethyl, carboxymethyl and thiosulfonic acid derivatives of rabbit fibrinogen subunits was investigated electrophoretically in sodium dodecyl sulfate containing polyacrylamide gels. Comparing carboxymethyl, carboxamidomethyl and thiosulfonic acid derivatives with the corresponding mercapto subunits divergent electrophoretic patterns were observed. Especially, the position of the Bbeta-chain was strongly dependent on the method of preparation. Similar results were obtained from investigating electrophoretic mobilities of albumin with differently substituted SH-groups after reduction with mercaptoethanol.

Albumins↗
PubMed1975

[Chemical properties of plasma fibrinogens and fibrins from normal and cobalt-treated rabbits].

The sulfitolysis products of fibrinogens from normal and cobalt-treated rabbits (5 mg Co2+/kg b.w.) were resolved by ion exchange chromatography on CM-cellulose columns. The elution patterns of both fibrinogens showed a distinct heterogeneity of gamma-chains. Furthermore, a gamma-chain derivative from cobalt fibrinogen could be distinguished electrophoretically from the corresponding one of normal fibrinogen because of its reduced electrophoretic mobility. Normal and cobalt fibrinogen did not differ from each other in their N-terminal (Val2 Ala2 Tyr2) and C-terminal (Pro1-2 Val4-5) amino acid compositions related to a subunit structure of A alpha 2 B beta 2 gamma 2, and their carbohydrate contents - neutral hexoses 1,21% (1,26%), N-acetyl hexosamines 1,16% (1,05%), N-acetyl neuraminic acid 1,19% (1, 13%), values for cobalt fibrinogen in parentheses. The main amounts of carbohydrates are bound to gamma- and B beta-chains, The BrCn cleavage products from cobalt fibrinogen and its gamma- and B beta-chains showed other electrophoretic properties than the corresponding derivatives from normal fibrinogen. But BrCN split products of A alpha-chains of both fibrinogens were electrophoretically very similar. Spectrographic investigations of the S-sulfoderivates demonstrated a diminution of the absorption maximum near 282mn of gamma and B beta derivatives of cobalt fibrinogen. A alpha-chains of both fibrinogens were not different from each other. Using autoradiography the highest 58Co binding could be found in the gamma-chain with a reduced electrophoretic migration velocity, whereas B beta-and gamma-chains with unchanged electrophoretic mobility bound only small amounts. A alpha-chains of cobalt fibrinogens were apparently not loaded with 58Co. gamma-chain and alpha-chain cross-links could be observed in normal fibrins stabilized by factor XII, however, in cobalt fibrins a gamma-dimer formation was demonstrable without participation of gamma-chains with reduced electrophoretic mobility. A distinct alpha-chain cross-link could not be demonstrated either. From these and other investigations on molecular weights of both fibrinogens it was assumed that earlier observed changes of physicochemical properties and biological behaviour of cobalt fibrinogen might result from a complex binding of cobalt ions on specific structures of the fibrinogen molecule.

Amino Acid Sequence↗