Biomedical subjects

B Burkert

Publications and source records attributed to B Burkert.

4 recordsLinked to original sources

PubMed2003

Effects of the mycotoxin ochratoxin A and some of its metabolites on human kidney cell lines.

The modulations of complement-regulating surface proteins on a human embryonic and a renal carcinoma cell line are described regarding the effects of ochratoxin A and some of its metabolites on the surface markers CD46, CD55 and CD59. Membrane integrity, cell proliferation and metabolic activity were reduced to different extents, depending on the kind of mycotoxin and the dosage, which was ranging from 10 to 1000 ng/ml. The number of cells carrying surface markers was suppressed significantly at 1000 ng/ml, in some cases even at 100 ng/ml, whereas the intensity of receptor expression on the positive cells was found to be stimulated. The fraction RE2 (OTC) isolated from an OTA-containing crude toxin surpassed the effects of all other ochratoxin metabolites. Apart from well-known cytotoxic and genotoxic effects modulation of cell surface marker expression by low concentrations of OTA and OTC deserves more attention with regard to its immuno-pathogenic importance. Furthermore, occurrence and impact of the mycotoxin OTC should be studied more into detail.

Antigens, CD↗

PubMed2002

[In vitro studies into the influence of ochratoxin A on the production of tumor necrosis factor alpha by the human monocytic cell line THP-1].

The influence of pure OTA and an Aspergillus-ochraceus crude toxin on the intracellular expression and the secretion of tumor necrosis factor (TNF) alpha by the monocytic cell line THP-1 was studied in vitro. After 4 hours exposure, the secretion of TNF alpha was inhibited to 50% by pure OTA in a concentration of 400 ng/ml and by crude toxin in a concentration of 100 ng/ml. The same concentrations of mycotoxins impaired the mitochondrial activity of THP-1 cells only marginally. The intracellular expression of TNF alpha was not disturbed by pure OTA in the concentrations tested, whereas crude toxin showed an inhibitory effect. The possible reasons for these findings are discussed.

Calcium Channel Blockers↗

PubMed2001

Immune reactions in cattle after immunization with a Mycobacterium paratuberculosis vaccine and implications for the diagnosis of M. paratuberculosis and M. bovis infections.

After immunization of four calves with a live modified Mycobacterium paratuberculosis vaccine the course of the humoral and cell mediated immune reactions was studied during a 2-year clinical investigation. Furthermore, the possibility of shedding of the vaccine strain and the influence of the vaccination on the tuberculin skin test was determined. In addition to standard procedures recently developed diagnostic methods (antibody enzyme-linked immunosorbent assay, interferon-gamma test, polymerase chain reaction) were used. A cell-mediated immune reaction, reflected in an increased, specifically induced, interferon-gamma production developed much earlier (1-2 weeks post-immunization) than humoral immunity (8-16 weeks post-gamma immunization). While the increase in antibody titres was transient, declining to extremely low levels 48-60 weeks post-immunization, cell-mediated immunity remained detectable until the end of the investigation. Spread of the vaccine strain into the body and shedding were never detected during the whole course of the study except for one colon site in one calf. As late as 2 years after vaccine application positive or doubtful skin reactions against M. bovis purified protein derivative were measured, reflecting possible interference of the immunization with the diagnosis of bovine tuberculosis. At the end of the investigation, a positive cell-mediated immune reaction was detected the control animal although clinical, pathological and bacteriological examinations gave no indication for a mycobacterial infection.

Animals↗

PubMed1993

[Care planning].

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Humans↗