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Biomedical subjects

P Rautenberg

Publications and source records attributed to P Rautenberg.

29 records · Page 2Linked to original sources
PubMed1987

A luminescence Western blot with enhanced sensitivity for antibodies to human immunodeficiency virus.

A luminescence assay was adapted for detection of peroxidase-labelled secondary antibodies, which react specifically with antibodies to human immunodeficiency virus on Western blots. This method is about one hundred times more sensitive than either commercial enzyme-linked immunosorbent assay or the chromogenic peroxidase assay on Western blots and detects seroconversion earlier than any other technique currently available.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Monospecific antibodies for detection of Clostridium difficile enterotoxin.

Tests of polyclonal antisera to homogeneous enterotoxin preparations of Clostridium difficile by immunoblotting demonstrated that cross-reactions occurred with proteins from cell lysates of nearly all Clostridium species. There was a notable reduction in the amount of crossreaction when only culture supernatants were analysed. The enterotoxin could be easily identified by its unique high molecular weight of 230,000. The findings suggest that care must be taken when immunological tests other than immunoblotting are used for detection of Clostridium difficile enterotoxin.

Antibodies, Bacterial↗
PubMed1986

Detection of Clostridium difficile Toxin A by immunoblotting.

A clinical isolate of Clostridium difficile has been tested for its toxin production. Both toxins, toxin A and toxin B, could be detected by tissue culture and in animal models as well. Antibodies against a crude toxin A preparation have been prepared. These antibodies are able to neutralize the toxin both in the mouse lethality test and tissue culture test systems. The specificity of this antiserum has been analysed by electroimmunoprecipitation methods. Using immunoblotting, it could be demonstrated that the antigenicity of toxin A after SDS polyacrylamide gel electrophoresis under denaturing and reducing conditions was still preserved. The molecular weight of toxin A has been estimated to be 250000. Immunoblotting offers a simple and reliable procedure for toxin A detection from culture supernatants of C. difficile.

Animals↗
PubMed1985

[Experiences with cytomegalovirus hyperimmunoglobulin after bone marrow transplantation].

The effects of an intravenous hyperimmune cytomegalovirus globulin after bone marrow transplantation are reported. From day -1 22 patients received 2 ml/kg body weight every two weeks during the first four months after BMT. Infusions were tolerated without any side effects. In three patients a CMV-infection could be documented which was symptomatic in two of them. A further patient experienced a CMV infection during the pretransplant phase before hyperimmune globulin had been administered. The most severe case presented as a nonlethal interstitial pneumonia.

Adolescent↗
PubMed1982

Study on a proteolytic enzyme from Trypanosoma congolense. Purification and some biochemical properties.

A protease has been purified from Trypanosoma congolense bloodstream forms by osmotic disruption, freeze-thawing of the cells, followed by chromatography using Thiopropyl-Sepharose and gel filtration. The enzyme is a thiolprotease. A combination of SDS-polyacrylamide gel electrophoresis and contact print zymograms using casein as substrate showed a single proteolytic band with a molecular weight of 31 000. The isoelectric point of the enzyme as ascertained by isoelectric focusing extended from pH 4.4 to 5.5 with a maximum at pH 5.0. The protease cleaved various heat denatured substrates such as casein, hemoglobin, albumin and ovalbumin. The highest enzyme activity was observed at pH 5.5 and pH 6.0 using casein and hemoglobin as substrates respectively. The max. temperature was found to be 50 degrees C. The enzyme is inactivated by mercurial compounds, iodoacetamide, iodoactate, chloromethylketones and leupeptin and is activated by dithioerythritol.

Animals↗
PubMed1981

Purification of the variant antigens of Trypanosoma congolense: a new approach to the isolation of glycoproteins.

We describe a new and rapid method for the isolation and purification of the variant antigens of Trypanosoma congolense. The procedure consists of (a) partial lysis of trypanosomes with dioxane, (b) lectin-affinity-chromatography with Con A-Sepharose, (c) electrophoretic desorption and concomitant separation of Con A-Sepharose-bound glycoproteins in a granulated electrofocusing gel, (d) electrophoretic elution of focused proteins from the granulated gel particles. The efficiency of each step was followed quantitatively by affinity electrophoresis. 73% of the variant antigens originally present in a trypanosomal lysate could be recovered. From 10(10) trypanosomes 2 mg of pure variant antigen were obtained. The variant antigen of the trypanosome clone used exhibits heterogeneity in molecular weight as well as in electric charge.

Animals↗
PubMed1981

Sialic acids are responsible for charge heterogeneity of the variant surface glycoprotein of Trypanosoma congolense.

Intact living cells of Trypanosoma congolense can be labeled by periodate/borotritide. The procedure described introduces a radioactive label nearly exclusively into the variant surface glycoprotein (VSG). The label can be removed from the VSG by either neuraminidase treatment or by mild acid hydrolysis. Using thin-layer chromatography the labeled compounds comigrated with 5-acetamido [or 5-glycolamide]3,5-dideoxygalactooctulosonic acid and 5-acetamido [or 5-glycolamide]3,5-dideoxyarabinoheptulosonic acid. These are the compounds commonly obtained after periodate borotritide treatment of glycosidically-linked neuraminic acids. It is evident from the results that sialic acids are constituents of the carbohydrate moieties of the VSG of T. congolense. Sialic acids are responsible for the charge heterogeneity of the VSG which is observed after isoelectric focusing.

Animals↗
PubMed1980

Evidence for concanavalin A binding sites on the surface coat of Trypanosoma congolense.

Glycoproteins of Trypanosoma congolense have been detected on SDS-polyacrylamide gels using the Concanavalin A peroxidase technique. Using [35S]diazoniobenzenesulphonate as a marker for cell surface proteins it was possible to distinguish between internal glycoproteins and the surface coat proteins. On SDS-polyacrylamide gels Con A reacted with the surface coat proteins. Results obtained from Con A-induced agglutination of living trypanosomes indicated that sugars of the surface coat proteins were accessible to Con A. This was reinforced by the cytochemical visualization of Con A binding to the trypanosome surface. The results suggested that the surface coat protein contained alpha-linked D-mannosyl, D-glucosyl, or N-acetyl-D-glucosaminoyl residues, which are exposed exteriorly on the surface coat.

Animals↗
PubMedDate not supplied

Seroprevalence and significance of antibodies to hepatitis C virus in pediatric patients with malignant diseases.

The prevalence of antibodies to hepatitis C virus recombinant antigen c100-3 was determined in 82 pediatric patients with malignant diseases who received blood transfusions as support during their chemotherapy. By prescreening, 12 of 82 patients were repeatedly positive. No positive correlation was established neither with the number of transfused blood units nor with surrogate markers for hepatitis NANB like ALT or anti HBc. Additional testing by alternate test assays revealed discordant results in 11 of these patients. Possible explanations, like reactivity to test-immanent coexpressed antigens of Saccharomyces cerevisae are discussed.

Antineoplastic Agents↗
PubMedDate not supplied

Inhibition of the apolipoprotein B mRNA editing enzyme-complex by hnRNP C1 protein and 40S hnRNP complexes.

The apolipoprotein (apo) B mRNA can be modified by a posttranscriptional base change from cytidine to uridine at nucleotide position 6666. This editing of apo B mRNA is mediated by a specific enzyme-complex of which only the catalytic subunit APOBEC-1 (apo B mRNA editing enzyme component 1) has been cloned and extensively characterized. In this study, two-hybrid selection in yeast identified hnRNP C1 protein to interact with APOBEC-1. Recombinant hnRNP C1 protein inhibited partially purified apo B mRNA editing activity from rat small intestine and bound specifically to apo B sense RNA around the editing site. The inhibition of apo B mRNA editing by hnRNP C1 protein was not due to masking of the RNA substrate as the mutant protein M104 spanning the RNA-binding domain of hnRNP C1 protein bound strongly to the apo B RNA, but did not inhibit the editing reaction. The apo B mRNA editing enzyme-complex of rat liver nuclear extracts sedimented in sucrose density gradients around 22-27S, but did not contain hnRNP C1 protein that was found exclusively within 40S hnRNP complexes. The removal of 40S hnRNP complexes increased the activity of the 22-27S editing enzyme-complex. Adding back 40S hnRNP complexes with hnRNP C1 protein resulted in an inhibition of the 22-27S apo B mRNA editing enzyme-complex, while addition of 18S fractions had no effect. In conclusion, hnRNP C1 protein identified by two-hybrid selection in yeast is a potent inhibitor of the apo B mRNA editing enzyme-complex. The abundant hnRNP C1 protein, which is contiguously deposited on nascent pre-mRNA during transcription and is involved in spliceosome assembly and mRNA splicing, is a likely regulator of the editing of apo B mRNA which restricts the activity of APOBEC-1 to limited and specific editing events.

APOBEC-1 Deaminase↗