Biomedical subjects

Peter Zbinden

Publications and source records attributed to Peter Zbinden.

3 recordsLinked to original sources

PubMed2004

The evolution of microarrayed compound screening.

This review describes recent developments in the evolutionary process of microarrayed compound screening (microARCS to become a robust and efficient ultra-high-throughput screening technology. Improvements in compound spotting (including new quality-control methods), gel casting and imaging, together with software capable of automatic analysis and deconvolution of images, have helped to streamline the screening process. A variety of screening projects using cell-based and non-cell-based approaches have been successfully concluded using microARCS. Comparison of hits derived from standard microtitre-plate-based screening and from microARCS reveals excellent overlap. Furthermore, there seems to be no bias towards finding compounds within a particular range of logP values, even though compounds are solubilized from a dry state during the course of the assay.

Biological Assay↗

PubMed2004

High throughput screening of beta-amyloid secretion inhibitors using homogenous time-resolved fluorescence.

A cell-based assay using homogeneous time-resolved fluorescence has been developed for high throughput screening of putative beta-amyloid (Abeta)production inhibitors. In this assay, total Abeta is detected by simply adding two commercially available antibody complexes. The first was a biotinylated monoclonal antibody (4G8), specifically recognizing an epitope comprising the residues 17-24 of the Abetapeptide, complexed with europium cryptate-streptavidin conjugate. The second was a polyclonal antibody (BioS-N), raised against the N-terminus of the Abeta peptide, complexed with an allophycocyanin-anti rabbit antibody conjugate. Binding of the two complexes to the Abeta peptide brought europium cryptate (fluorescence donor) and allophycocyanin (fluorescence acceptor) into close proximity, consequently a fluorescent resonance energy transfer signal was produced upon excitation at 337 nm. The resulting fluorescence signal (665 nm) was then detected using a Discovery or a ViewLux reader. Detection of Abeta by the proposed method is possible at concentrations of approximately 1 nM. The method was employed for the detection of Abeta secreted from a stable transfected human neuroglioma cell line (H4) overexpressing a mutated form of the human amyloid precursor protein (APP695NL) and developed for robotic automation. At optimized conditions, signal-to-background ratios exceeding 5 and Z' factors around 0.7 were achieved in a 384-well format. High throughput screening of 56,913 potential Abeta production inhibitors led to identification of new non-cytotoxic and cell permeable compounds with potencies in the submicromolar range.

Amyloid beta-Peptides↗

PubMed1997

[Target proteins and mechanisms of ochratoxin toxicity. A contribution to the identification of potential ochratoxin antagonists]

Ochratoxins are mycotoxins released by moulds on grain, peanuts and vegetables. Toxicological investigations have shown that ochratoxin A displays nephrotoxic, genotoxic, teratogenic, cancerogenic and immunosuppressive effects. Increased blood levels observed in humans would seem to suggest a link to a kidney desease (Balcan Endemic Nephropaty) frequently observed in the Balkan countries. The adverse effects of ochratoxin A are mainly associated with its impact on phenylalanine-metabolizing enzymes. Based on the three-dimensional structure of phenylalanine-t-RNA-synthetase, its interactions with ochratoxins are analyzed as well as with Aspartam. In animal models, Aspartam has been shown to almost fully prevent toxic effects of ochratoxin A. The topology of the binding site of phenylalanine-t-RNA-synthetase would seem to be favorable towards a few affinity-enhancing modifications of the Aspartame molecule. A known molecular mechanism is a prerequisite for a systematic search of antagonizing substances for toxins. Based on a receptor structure, binding properties of such drugs can be identified and optimized using computer-aided drug design. Susequently, only the most potent candidate structures must be subjected to a determination of their biological activity, which can lead to a significant reduction of substances to be tested in vivo. Such experiments are particularly stressful as the animals must be intoxicated beforehand. The extent of an antagonistic impact on humans suffering from a chronical ochratoxin A intoxication must be subject of clinical studies.

Journal Article↗