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Biomedical subjects

D Herrmann

Publications and source records attributed to D Herrmann.

At least 73 records · Page 4Linked to original sources
PubMed1990

Mouse monoclonal antibody directed against hepatitis B virus X protein synthesized in Escherichia coli: detection of reactive antigen in liver cell carcinoma and chronic hepatitis.

A mouse monoclonal antibody directed against the protein product of the hepatitis B virus X open reading frame was prepared. This antibody was used to screen liver tissue sections from patients with chronic hepatitis (CH) and patients with liver cell carcinoma (LCC). Reactive antigen was detected by immunohistochemistry in about 30% auf the samples from CH patients and in about 80% of the samples from LCC patients regardless of whether tumor or surrounding nontumor tissue was analyzed. A predominant localization of the antigen in the cytoplasm was observed. In liver sections of CH patients the presence of HBx or HBx-related protein appeared to correlate with the presence of the classical viral antigens HBs- and/or HBcAg. A similar correlation was not found in liver or tumor tissue samples from LCC patients. The occurrence of X-monoclonal-antibody-reactive protein (Xarp) at a low frequency in liver tissue from patients without hepatitis B virus related disease suggests that Xarp in some cases may not be identical with the putative viral X antigen.

Animals↗
PubMed1989

DNA polymorphism of the human complement C8 beta gene: formal genetics and intragenic localization.

The eighth component of human complement consists of three subunits of different molecular mass, which are coded for by three separate genetic loci. Polymorphisms have been described at the protein level for the alpha and beta subunits by means of sodium dodecyl sulfate gel electrophoresis and isoelectric focusing. Using a full-length human C8 beta cDNA probe, we have studied more than 100 individuals by Southern blot analysis to detect DNA polymorphisms. We have found two restriction fragment length polymorphisms (RFLPs) with the enzymes Taq I and Bam HI. The Taq I polymorphism is defined by two alleles, i.e., a single 4.9 kb fragment or two 2.8/2.1 kb fragments. The allele frequencies are 0.68 and 0.32, respectively. The second RFLP with Bam HI is correlated with the Taq I variants: 3 kb Bam HI; 4.9 kb Taq I and 3.3 kb Bam HI; 2.8/2.1 kb Taq I. Both RFLPs could be mapped to the 3' portion of the C8 beta gene. Based on the size of genomic restriction fragments, the C8 beta gene can be estimated to have a size of 32-36 kb. Because of the even frequency distribution, the C8 beta DNA polymorphisms may be useful in gene mapping and disease association studies.

Alleles↗
PubMed1989

Isolation of timothy (Phleum pratense) allergens using affinity chromatography with monoclonal antibodies.

The monoclonal antibody 1 D11, directed against the timothy pollen allergens I, II, III, and a further, anodically migrating component, is suitable for the isolation of these allergens by means of affinity chromatography. The purified allergens consist of glycoproteins with many different isoelectric points. Their molecular weights were estimated as approximately the same as those of the allergens in the whole timothy pollen extract. Their allergenic activity (IgE binding) was not lost during the purification steps.

Allergens↗
PubMed1989

Adhesion of platelets to purified solid-phase von Willebrand factor: effects of wall shear rate, ADP, thrombin, and ristocetin.

When platelets are stimulated with adenosine diphosphate (ADP), thrombin, or ristocetin, they bind soluble von Willebrand factor (vWF). In contrast, platelets adhere to solid-phase vWF without apparent stimulus. This work characterizes the adhesion of washed human platelets to highly purified solid-phase human vWF. VWF (iodine 125-labeled vWF) was demonstrated to bind in a quantifiable fashion to the internal surfaces of glass capillary tubes, saturating at a surface density of 3.0 mg/ml. The multimeric structure of bound vWF was the same as that of normal vWF. Platelets were washed, labeled with indium 111, and resuspended with washed red blood cells (RBCs) in balanced salt solution containing Ca++, Mg++, and apyrase. The washed platelet RBC suspension was aspirated through capillary tubes to which vWF was adsorbed. Adhesion of platelets to adsorbed vWF was directly dependent on the surface density of vWF. Increasing wall shear rate (100 to 5000 sec-1) produced increasing platelet adhesion to maximum reached at 2500 sec-1. Platelets bound to the solid-phase vWF in an irreversible fashion, and, as demonstrated with scanning electron microscopy, they spread on the surface. When used to stimulate the platelets, ADP, thrombin, and ristocetin all increased the platelet adhesion to solid-phase vWF. ADP- and thrombin-stimulated reactions were inhibited by prior treatment of the platelets with 5'-p-fluorosulfonylbenzoyl adenosine. This inhibitor of ADP binding had no effect on the baseline platelet adhesion reaction (without ADP or thrombin). Adenosine in concentration up to 1 mmol/L failed to inhibit adhesion. The data demonstrate that washed platelets adhere to solid-phase vWF without added agonists, that the reaction is dependent on surface density vWF and wall shear rate, that they bind irreversibly, and that they demonstrate surface spreading. In addition, these platelets can be stimulated to increase their adherence to vWF by using ADP, thrombin, and ristocetin.

Adenosine Diphosphate↗
PubMed1987

Determination of IgE rheumatoid factor. Comparison of a solid-phase radioimmunoassay and an enzyme immunoassay.

A solid-phase radioimmunoassay and an enzyme-linked immunosorbent assay have been developed for the identification of IgE rheumatoid factor (IgE RF). For both, human IgG was used as antigen. Bound IgE RF was detected by means of commercially available rabbit anti-human IgE antiserum and 125I-labelled sheep anti-rabbit IgG as well as monoclonal anti-human-epsilon-chain antibody and horse-radish peroxidase-labelled sheep anti-mouse IgG. The presence of IgM RF did not cause false positive results. Correlation in the results of both assays were significant, the reproducibility was very good. In 50.6% of 79 sera from patients with rheumatoid arthritis IgE RF has been detected with both or one of the methods. Only in 1 out of 12 seronegative rheumatoid arthritis sera IgE RF was identified.

Arthritis, Rheumatoid↗
PubMed1985

[The quantitative determination of the IgM rheumatoid factor using a solid-phase radioimmunoassay. Comparison with the agglutination test and the radioimmuno-polyethyleneglycol precipitation test].

A solid-phase radioimmunoassay capable of detecting nanogram quantities of human IgM rheumatoid factor using a monoclonal anti-mu-chain antibody is described. Human IgG did not interfere with the detection of IgM RF by this method. The small nonspecific binding of nonRF IgM to the human IgG coated tubes utilized in the assay must be corrected for by assaying samples in parallel bovine serum albumin coated control tubes only in cases of deviation of IgM from normal range. 69 coded and randomly arranged sera from patients with rheumatoid arthritis (RA), nonrheumatic joint diseases and healthy adult control subjects were investigated by this method, agglutination techniques as well as RIPEGA. A good correlation between solid-phase radioimmunoassay and agglutination techniques was found. Patients with seropositive RA had significantly higher concentrations of IgM RF than seronegative RA patients or control subjects (mean +/- 1 SD = 133,3 +/- 187,2 micrograms/ml versus 4,7 +/- 6,5 micrograms/ml and 2,2 +/- 4,0 micrograms/ml; resp.).

Agglutination Tests↗
PubMed1981

On the mechanism of inhibitory effect of violamycin antibiotics on the transcription by bacteriophage T3-induced RNA polymerase.

The effect of three components of the anthracycline antibiotic violamycin on the transcription of bacteriophage T3 DNA by bacteriophage T3-induced RNA polymerase has been investigated in a cell-free system. The glycosides of violamycin BI possess the highest inhibitory activity, whereas those of violamycin BII and violamycin A show a reduced inhibitory effect. Concentrations of violamycin BI depressing the incorporation of (3H)UMP into RNA chains have only a slight effect on the binding of the T3 RNA polymerase to T3 DNA and on the incorporation of GTP as the first nucleotide. This shows that the primary target of the antibiotic is not the initiation of the RNA synthesis. The binding of violamycin BI to T3 DNA causes a strong reduction of the elongation rate of the RNA chains.

Aminoglycosides↗
PubMed1980

[Significance of the immune complex reaction in internal medicine].

A review is given concerning occurrence, identification, and pathogenetic effects of immune complexes. The formation of immune complexes by interaction of antigen with antibody, is a component of the normal immune response. In cases with inefficient clearance by the mononuclear phagocyte system only, pathological consequences will be expected, in particular by immune complexes formed with moderate excess of antigen. For the identification of immune complexes in biological fluids many methods have been developed. The methods are based mostly on biological activities of immune complexes, e.g. interaction with complement or rheumatoid factor and reactivity with cellular receptors. These antigen-nonspecific methods do not allow to discriminate between true immune complexes and nonspecifically aggregated immunoglobulins. Circulating immune complexes become fixed to basement membranes of the body. They can produce an acute inflammatory reaction by activation of complement and inflammatory cells and also interfere with the immune response. Circulating immune complexes have been detected in some human diseases, e.g. autoimmune diseases (LEV, RA), infectious diseases, malignancies, serum sickness syndrome, immune-complex glomerulonephritis, and after transplantation. The possibilities for management of immune complex diseases are discussed.

Antigen-Antibody Complex↗