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Biomedical subjects

R Kurth

Publications and source records attributed to R Kurth.

At least 163 records · Page 9Linked to original sources
PubMed1986

Detection of antibodies to HTLV-III in commercially available immunoglobulin preparations.

Samples of 96 polyvalent and virus-specific immunoglobulin batches commercially available in West-Germany were tested by enzyme-linked immunoassay and immunoblot for the presence of anti-HTLV-III antibodies. 37% of the polyvalent and 87% of the virus-specific batches were positive. It was concluded that these preparations are still safe and because of their reportedly low titer neutralizing antibodies possibly beneficial in certain cases, such as newborns of HTLV-III positive mothers or after accidental exposure to infectious material in clinics or laboratories.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Functional purification and enzymic characterization of the RNA-dependent DNA polymerase of human immunodeficiency virus.

The RNA-dependent DNA polymerase (RDDP) of human immunodeficiency virus (HIV) was purified from sucrose density gradient-banded virus by four successive procedures: anion exchange chromatography, cation exchange chromatography, affinity chromatography on oligo(dT)-cellulose and adsorption chromatography on hydroxyapatite. The enzyme preparation was free of cellular DNA-dependent DNA polymerase activity. The properties of HIV RDDP were determined with a variety of template-primers. Generally, the enzyme used Mg2+ for optimal activity except with (Cm)n X (dG)12-18 as template-primer. Kinetic data (Michaelis constant, Hill coefficient) were calculated for several substrates.

Chromatography↗
PubMed1985

Serum antibodies to human T-cell leukaemia virus type I in different ethnic groups and in non-human primates in South Africa.

The prevalence of humoral antibodies to human T-cell leukaemia virus type I (HTLV-I) was investigated in different ethnic groups and in non-human primates in South Africa. Serum antibody levels were determined by enzyme-linked immunosorbent assay (ELISA) using either disrupted whole HTLV-I or purified p24 core protein (p24 HTLV-I) as antigens. ELISA was complemented by direct radio-immunoprecipitation assays using either purified iodinated p24 HTLV-I or radiolabelled lysates of an HTLV-producing cell line as antigen followed by sodium dodecyl sulphate polyacrylamide gel electrophoresis of the immunoprecipitates, and by immunofluorescence using the HTLV-I-producing cell line HUT-102 as antigen. Antibodies were demonstrated in 3,5% of Asians, 3,5% of blacks and 4,1% of coloureds, but not in whites, and also in 29% of vervet monkeys and 33% of baboons. We conclude that HTLV-I or closely related viruses cause widespread infection in non-human primates in South Africa and in a lower percentage of humans, including apparently healthy blood donors. We are currently isolating retroviruses from seropositive reactors and investigating the possible relevance to disease in South Africa.

Adult↗
PubMed1985

Seroepidemiology of HTLV-III (LAV) in the Federal Republic of Germany.

In 1984 10,281 sera were collected in the FRG and examined for antibodies to HTLV-III (LAV) with an enzyme-linked immunosorbent assay and confirmative tests. Of the German AIDS patients 81% have antibodies. Individuals belonging to AIDS risk groups, homosexuals, haemophiliacs and i.v. drug abusers, have antibody frequencies between 25%-72%. The detection of HTLV-III antibodies in blood donors indicates that the virus is being transmitted by blood transfusions.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Isolation of monoclonal antibodies specific for Rous sarcoma virus structural, polymerase and transforming proteins and their use for the study of mutant virus-infected cells.

Monoclonal antibodies were developed that are specific for Rous sarcoma virus structural, polymerase (reverse transcriptase) and transforming proteins. The monoclonal antibodies were shown to bind to purified virus proteins in an indirect 125I-labelled Protein A binding assay suitable for screening even very large numbers of hybridomas. Additional tests for specificity included radioimmunoprecipitation of purified virus structural proteins P12 and P27, of reverse transcriptase subunits alpha and beta, and of the transforming protein pp60v-src. Pilot immunofluorescence and protein kinase assays of the expression of virus proteins in avian and mammalian cells infected by wild-type virus as well as by temperature-sensitive, transformation-defective virus mutants revealed that synthesis of virus structural and transforming proteins is hardly affected by changes in temperature, whereas the pp60v-src-associated kinase activity is temperature-sensitive in cells infected by most, but not all the virus mutants.

Animals↗
PubMed1984

A small scale indirect 125iodine-labelled protein A binding assay for detection of monoclonal antibodies against avian oncoviral proteins.

A small scale solid-phase radioimmunoassay employing 125I-labelled protein A is described which is suitable for screening large numbers of monoclonal antibodies directed against antigens which can be prepared in small amounts only, for example oncoviral proteins. The use of polystyrene Terasaki microtest plates instead of 96-well microtitre plates reduces the amount of antigen required for screening hybridoma supernatants to less than 30 ng/well. This method facilitates washing procedures and reduces the quantity of radioactive waste. The sensitivity and specificity of the method is demonstrated by the isolation and initial characterization of monoclonal antibodies specific for avian oncoviral transforming, structural and polymerase proteins.

Animals↗
PubMed1984

[Active immunization against hepatitis B].

The efficacy of the hepatitis B vaccine Hevac B Pasteur was assessed in 277 persons over a period of 6 months. HBs antigen of 5 micrograms/dose was administered three times in monthly intervals. Before each vaccination and after 6 months 18 chemical pathology data and a clinical assessment were performed and all important serologic hepatitis markers (anti-HBs, anti-HBc, HBs antigen, HBc antigen, anti-HBe) were determined radioimmunologically. Within two months antibodies against the surface antigen (anti-HBs) had developed in 85.7% of vaccinees. After 6 months 93.1% of vaccines had become seropositive. Within the first two months anti-HBs-positive findings and higher anti-HBs concentrations occurred significantly more frequently (P less than 0.048) in females than in males. These differences had largely disappeared at the follow-up assessment in the sixth month. In contrast, both parameters (seroconversion rate and anti-HBs concentration) were age-dependent. Among vaccines of less than 25 years of age and of more than 35 there were significant differences after 6 months (P less than 0.005). The hepatitis B vaccine of the Pasteur institute can be considered immunogenic and safe.

Adult↗
PubMed1984

Monoclonal antibodies specific for the avian sarcoma virus transforming protein pp60src.

Monoclonal antibodies to avian sarcoma/leukosis virus-coded transforming, structural, and polymerase proteins have been developed. In this first communication, a monoclonal antibody to pp60src will be characterized. The antibody can bind to pp60src in radioimmunoassays, precipitates this antigen in protein kinase tests, and demonstrates in immunofluorescence investigations that pp60src has different intracellular localizations depending on whether RSV-transformed avian or mammalian cells are studied.

Alpharetrovirus↗
PubMed1984

Human teratocarcinomas cultured in vitro produce unique retrovirus-like viruses.

We have previously reported that among a series of human tumours investigated, only human teratocarcinoma cell lines derived from testicular tumours or pulmonary metastases of patients in Germany and the U.S.A. produced retrovirus-like particles spontaneously, albeit in low amounts. In a recent publication electron microscopical data suggested that the human teratocarcinoma-derived ( HTD ) particles were morphologically closely related, but not identical, to the type C retroviruses of animals. In this communication, the explantation of three human teratocarcinoma cell lines is briefly described. Evidence is presented that HTD particles (i) are synthesized only in a fraction of the epithelioid and differentiating cells; (ii) can be induced biochemically in a manner characteristic of retroviruses; (iii) either are not infectious or possess a peculiar host range; (iv) are immunologically unrelated to animal retrovirus strains; (v) possess an endogenous RNA-dependent DNA polymerase activity that can be banded at 1.16 g/ml in linear sucrose gradients. These results may be taken as suggestive evidence that HTD particles represent a novel group of unique retroviruses.

Antigens, Viral↗
PubMed1983

The functional significance of tumour-associated cell surface alterations of embryonic and unknown origin.

The study of the phenotype of tumours aims to elucidate cell surface alterations that could be used for diagnostic, prognostic or therapeutic purposes. As tumours tend to escape the homeostatic growth control mechanisms of the host, it can be assumed that plasma membrane alterations are also responsible for the antisocial behaviour of tumour cells. Selected features of the transformed phenotype, of fetal or unknown origin, namely tumour-associated antigens, isozymes and growth factors, are discussed in relation to the altered growth pattern of the tumour cell. It is concluded that definitive structure-function relationships have not yet been established, but areas for future investigation are suggested.

Animals↗
PubMed1983

Oncogenes in retroviruses and cells.

Oncogenes are genes that cause cancer. Retroviruses contain oncogenes and cause cancer in animals and, perhaps, in man. The viruses have appropriated their oncogenes from normal cellular DNA by genetic recombination. Correspondingly, uninfected vertebrate cells contain a family of evolutionary conserved cellular oncogenes. Retrovirus infection, introducing additional viral oncogenes into the cells, as well as carcinogen-mediated activation of cellular oncogenes may both lead to increased synthesis of oncogene encoded transforming proteins which convert normal cells to tumor cells. Unique retroviruses of human origin have recently been identified. They may, on occasion, directly cause tumors in man. However, the general significance of retroviruses may better be illustrated by their remarkable genetic composition which allows them to promote tumor growth by a variety of genetic mechanisms.

Animals↗
PubMed1983

Structural organization of unique retrovirus-like particles budding from human teratocarcinoma cell lines.

Human teratocarcinoma cells cultured in vitro can be induced to produce retrovirus-like particles. The induction procedures are the same as those previously shown to induce the synthesis of animal retroviruses. Electron microscopical evidence is presented that the human teratocarcinoma-derived (HTD) particles are most closely related to the type C retrovirus strains. HTD particles can be banded at 1.16 g/ml in linear sucrose gradients, the characteristic density for retroviruses, and subsequently be used for negative staining and fine structure analysis.

Cell Line↗