PubMed Health⌕ Search

Biomedical subjects

A Stemberger

Publications and source records attributed to A Stemberger.

At least 37 records · Page 2Linked to original sources
PubMed1978

[Detection of human proteins in the epoxy housing of implanted cardiac pacemakers (author's transl)].

On cardiac pacemakers with epoxy resin encapsulation of a certain type which had been implanted in humans for a considerable time, sessile human proteins were detected in the epoxy by means of immunofluorescence microscopy. These proteins are not extractable from shavings of the epoxy casing using the method described, as was shown by two different methods. The results of LOWRY's test on the eluate are invalid, because we assume that extractable amino groups are responsible for the positive results.

Amino Acids↗
PubMed1977

Complex formation of crosslinked fibrin oligomers with agarose-coupled fibrinogen and fibrin.

Soluble oligomers of fibrin were produced by limited incubation of fibrinogen with thrombin in the presence of calcium2 positive earth, cysteine and factor XIII. They were separated from fibrinogen by gel filtration. Gamma-gamma dimers were demonstrated in fractions from the void volume and the shoulder prior to the fibrinogen peak. These fractions were subjected to affinity chromatography on agarose-coupled fibrinogen and fibrin. Cross-linked oligomers of fibrin were adsorbed to agarose-coupled fibrin, whereas no adsorption occured during affinity chromatography on agarose-coupled fibrinogen. This indicates that crosslinked fibrin oligomers have no affinity to fibrinogen, yet readily form complexes with fibrin.

Chromatography, Affinity↗
PubMed1975

Soluble fibrin monomer complexes demonstrated by agarose gel filtration and by adsorption on insolubilized fibrinogen: a comparative study.

Incubation of fibrinogen with small amounts of thrombin resulted in the occurrence of soluble fibrin monomer complexes. These complexes consisted predominantly of a derivative with a higher molecular weight than that of fibrinogen. It was characterized by its relative electrophoretic mobility in 5% PAA gel (0.28 X 10(-5) cm2/V X sec) and its elution position prior to the fibrinogen peak following gel filtration. Using adsorption chromatography on insolubilized fibrinogen the derivative dissociated at a ratio of almost 1 : 1 into one part which was adsorbed and into fibrinogen which was not adsorbed. The part which was adsorbed seemed to be the thrombin mediated fibrin monomer. This study confirms the concept that dissociable dimeric fibrinogen-fibrin monomer complexes occur after limited action of thrombin on fibrinogen.

Adsorption↗
PubMed1975

Heterogeneity of clottable fibrinogen isolated from plasma by affinity chromatography.

Human fibrinogen was adsorbed on thrombin-activated fibrinogen which had been immobilized by covalent coupling with Sepharose-6B (Fibrin-Sepharose). Subsequent desorption with a buffer containing 1 M KBr yielded a protein which, after removal of KBr, showed a clottability of 83%. If the same procedure was applied to plasma, a fibrinogen-containing fraction with a clottability of 90-95% was obtained. In addition to fibrinogen, it comprised substances of higher and lower molecular weight, as shown by gel electrophoresis. Following adsorption on DEAE-cellulose at pH 8.8, several fractions were obtained by a stepwise elution technique with buffers of increasing molarity and decreasing pH. The first contained fibrinogen with partially degraded Aalpha-chains. It was followed by unaffected fibrinogen. In subsequent fractions, fibrinogen was associated with another protein which, in dodecylsulfate gel electrophoresis, migrated with a rate similar to that of the gamma-chains. The last fraction contained high molecular weight substances which, by reduction, yielded a relatively high molecular weight cleavage product and some subunits of lower molecular weight. Finally, a stepwise elution from Fibrin-Sepharose was elaborated to fractionate adsorbed plasma proteins. A fraction giving only a slight reaction with antifibrinogen was eluted with KBr-free buffer at 37 degrees C. Subsequent desorption with a buffer containing 1 M KBr removed fibrinogen of 83% clottability with only minute amounts of accompanying proteins.

Chromatography, Affinity↗