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Biomedical subjects

K Rother

Publications and source records attributed to K Rother.

At least 37 records · Page 2Linked to original sources
PubMed1985

The role of complement in inflammation.

The inflammatory process may be initiated by a great variety of stimuli. Amongst the diverse pathogenic pathways that lead from the primary stimulus to the tissue response, the serum complement system (C) seems the most important and, certainly, it is the best analyzed of the mediator systems.

Complement Pathway, Alternative↗
PubMed1985

Insulin and anti-insulin antibody interaction. Evidence for the formation of 7 S and 10 S structures.

The clearing of monoclonal and polyclonal and anti-insulin antibodies from homogeneous solutions at 100,000 X g was used to estimate the size of soluble insulin-antibody complexes at physiologic concentrations. Monoclonal antibodies cleared as a uniform population of 6.6 S independent of the insulin concentration. Polyclonal antibodies cleared as 6.6 S monomers at saturation and as 10 S particles when the amount of insulin bound decreased, suggesting that a soluble complex with two antibodies was formed. An increase of the affinity and a decrease of antibody valency can be related to the complex formation. The binding affinity of polyclonal sera depends on the composition of the affinities of the IgG monomers and on their ability to form 10 S complexes. The formation of insulin-antibody dimers precludes cross-linking and precipitation. Both types of insulin-antibody complexes have been found in the sera from patients treated with bovine insulin.

Animals↗
PubMed1984

Freeze-thaw activation of the complement attack phase: II. Comparison of convertase generated C--56 with C--56 generated by freezing and thawing.

The activation of the C-attack phase does not necessarily involve the components of the C5 convertases. C--56 hemolytic activity was generated from the same source of C7 depleted serum by the alternative pathway convertase or by freezing and thawing resp. In contrast to activation by the convertase, biological activities of C5a (chemotaxis, serotonin release) were not detected following activation by freezing. The yields of C--56 hemolytic activities were similar and the properties of the activated products were identical. No difference was found in the molecular weight, in the hydrophobicity or with respect to charge. The two activities were in the absence of C7 stable at 37 degrees C and decayed rapidly in the presence of C7. It is proposed that a conformational change in the tertiary structure of the molecule(s) is the critical event in the formation of an active C--56 complex. In this light the cleavage of C5a from the native molecule by the convertase appears as a side reaction, not by itself essential for activation.

Complement Activating Enzymes↗
PubMed1984

Freeze-thaw activation of the complement attack phase: I. Separation of two steps in the formation of the active C--56 complex.

The activation of the attack phase of C, C5-C9, is generally assumed to be dependent on the enzymes of the C activation pathways which cleave C5 into C5b and C5a. C5b will then form a complex with C6 that binds to membranes and, in the presence of C7-C9, effects cell lysis. In contrast, however, a variety of physicochemical means was found to activate C5 + C6 independently of the convertases and without apparent generation of the C5a peptide. By freezing and thawing of C5 + C6 a hemolytic C--56 activity was generated: (C--56 ).f The activation proceeded in two steps: (1) during a preincubation period of the two components the time and temperature dependent formation of an activatable intermediate was observed and (2) the intermediate C--56 could then be endowed with hemolytic activity by freezing and thawing. The intermediate as well as the activated (C--56)f complex was separated from C5 and C6 by anion exchange chromatography. While the isolated intermediate was labile, the active product after freezing and thawing was stable.

Complement Activation↗
PubMed1983

[Immunopathology of pyelonephritis].

Urinary tract infection (as apposed to symptomless bacteriuria) begins with the binding of the bacterium to the epithelium lining the urinary tract. Immune SIgA2 may react with the bacterial ligands ("adhesins") thus blocking their attachment to the epithelium. In the absence of the protective blockade tissue lesions ensues. The pathomechanism of the circumscript interstitial inflammatory spots is assumed to depend on complement activation by immune complexes of bacterial antigens and antibodies: chemotactic activity is generated from the C-system, leucocytes are attracted and the lysosomal enzymes initiate tissue damage.

Animals↗
PubMed1978

Deviated lysis: lysis of unsensitized cells by complement. V. Generation of the activity of low pH or low ionic strength.

In serum exposed to acid pH (6.4), a serum activity was generated which lyzed unsensitized erythrocytes in the presence of EDTA. It was similar to the d.l. activity found following serum activation by inulin (2). In contrast to the d.l. generation by the classical or by the alternative pathway of C activation, the generation of d.l. by acid pH did not require C4 plus C2 or C3 plus factor B resp. It was, thus, not dependent on any hitherto known pathway of C activation. A similar activity appeared when NHS was centrifuged in a sucrose gradient at low ionic strength. Physicochemical alterations of the component proteins which influence their affinity for each other are seen as the basis for the activation of the attack phase of C.

Animals↗
PubMed1977

Deviated lysis: transfer of complement lytic activity to unsensitized cells. IV. Parital isolation of the activity.

Deviated lysis (d.l.) was previously characterized as the lysis of non-sensitized erythrocytes by activated complement (C) in the presence of EDTA (1, 2, 3). The lytic activity was present in serum fractions of a m.w. in the proximity of 220,000. All the C factors C5 through C9 were found in these fractions and they were all needed for lysis. It is proposed that in d.l. small aggregates of the C components C5 through C9 coexist in the reaction mixture without further interaction. Only when appropriate receptors such as present on target cells surfaces are available, the factors react in a sequential order eventually to result in lysis of the target cell.

Animals↗
PubMed1976

Deviated lysis: Transfer of complement lytic activity to unsensitized cells II. Generation of the activity by inulin and by antigen antibody complexes.

Deviated lysis (d.l.) activity, i.e. lysis of unsensitized cells by lytic C activity, was generated via the classical pathway of Cactivation (ag ab complexes) and via the alternative pathway (inulin). The activity was observed on the surface of the activating particles and in the fluid phase. The activity was relatively stable at 32 degrees C. Its generation involved the C components C6 through C9 and possibly also C5.

Animals↗