Biomedical subjects

S Oscarsson

Publications and source records attributed to S Oscarsson.

4 recordsLinked to original sources

PubMed1991

Thiophilic adsorbents for RIA and ELISA procedures.

Three types of agarose derivatives have been prepared and investigated as adsorbents for radioimmunoassay and ELISA analysis. The analytical systems were evaluated using beta 2 microglobulin as a model. After a competitive reaction between the immunocomponents in solution, the formed immune complexes were adsorbed onto the adsorbent in the presence of 0.5 M potassium sulfate in 0.1 M Tris, pH 7.5. The binding constant between the interaction site on human IgG and the adsorbent 3-(2-pyridylthio)-2-hydroxypropylagarose (Py-S-gel) was determined to be 1.5 x 10(7) M-1 and the binding capacity was 20 mg/ml gel. The immune complex was desorbed by deleting potassium sulfate from the buffer, and only 0.5% of the total applied protein remained after washing the adsorbent with 0.5 M NaOH. The same adsorbent can be used repetitively with different systems.

Animals↗

PubMed1991

Immunocomplex-immobilization technique.

An immunoassay technique is presented, which works equally well with either a radioactive isotope or an enzyme as the label. It is based on the competition between a labelled antigen of known concentration and an unlabelled antigen (concentration to be determined) for binding to an antibody, which previously has been thiolated by the heterobifunctional reagent N-[3-(2-pyridyldithio)propionyl]succinamide [marketed as N-succinimidyl-3-(2-pyridyldithio)propionate; SPDP)]. The soluble immunocomplex formed is then immobilized onto agarose beads containing reactive disulphide groups. After washing, to remove any unbound and non-specifically adsorbed material, the radioactivity or the enzymic activity on the agarose beads is determined and the concentration of the antigen in the test sample calculated according to the conventional procedure for a competitive immunoassay. In order to demonstrate the applicability of the technique a test procedure for the determination of total serum immunoglobulin E is presented.

Immunoglobulin E↗

PubMed1990

Protein chromatography with pyridine- and alkyl-thioether-based agarose adsorbents.

In an attempt to identify the part of the ligand of 3-(2-pyridylthiol)-2-hydroxypropylagarose that is responsible for the specific adsorption of immunoglobulins and alpha 2-macroglobulin from serum, nine agarose derivatives were prepared: (I) 3-(N-2-iminopyridyl)-2-hydroxypropyl-, (II) 3-(4-pyridylthio)-2-hydroxypropyl-, (III) 3-(2-pyridylthio-N-oxide)-2-hydroxypropyl-, (IV) 3-(2-pyridylthio)-2-hydroxypropyl-, (V) 3-(ethylthio)-2-hydroxypropyl-, (VI) 3-(n-butylthio)-2-hydroxypropyl-, (VII) 3-(2-aminoethylthio)-2-hydroxypropyl-, (VIII) 3-(2-hydroxyethylthiol)-2-hydroxypropyl- and (IX) 3-(N-2-pyridyl-2-one)-2-hydroxypropylagarose. The selective adsorption of the above serum proteins to these derivatives was analysed by chromatography. The electron distributions were calculated for three of the investigated pyridine derivatives in order to establish whether there is any relationship between the electron distribution in the molecule and the absorption properties of the pyridine derivatives. By optimizing the preparation methods for the different derivatives, the possible side-reactions were minimized and checked. The adsorbed serum proteins were determined by the Ouchterlony technique and electrophoresis. The concentration of human serum albumin in the different fractions was determined by conventional radioimmunological methods. These data make it possible to classify the adsorbents according to their selectivity and hydrophobic thiophilic behaviour.

Chromatography, Agarose↗

PubMed1989

Covalent chromatography and salt-promoted thiophilic adsorption.

Covalent chromatography on 3-(2-pyridyl disulfido)-2-hydroxypropyl agarose, abbreviated PyS2, turns out to involve more complex interactions than has been supposed heretofore. Unexpectedly, the sorption is highly salt dependent. The relative affinities for serum proteins have therefore been determined in the absence and presence of different types of salts at different salt concentrations and with different degrees of ligand substitution on the adsorbent. In the presence of water-structuring salts the PyS2-gel shows an adsorption pattern for serum proteins resembling that of the "thiophilic" T-gel (J. Porath; F. Maisano, and M. Belew (1985) FEBS Lett. 185, 306-310). Superimposed on thiophilic adsorption we have found, as expected, covalent attachment of thiol-containing proteins. Also the thiol-disulfide exchange increases from 4-5% in the absence of potassium sulfate or sodium chloride up to about 40% of the applied serum proteins when such a water-structuring salt is present. We have thus shown that the interaction of a protein with the ligand is greatly facilitated by a water-structuring salt--and in this case the product is a covalently as well as a thiophilically immobilized protein. A cautious interpretation of protein interaction phenomena is justified whenever ligands containing sulfide, disulfide, or pi-electron-rich structures such as aromatic moieties are involved.

Adsorption↗