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Biomedical subjects

David A Dunn

Publications and source records attributed to David A Dunn.

5 recordsLinked to original sources
PubMed2005

Foundation Review: Transgenic animals and their impact on the drug discovery industry.

The ability to direct genetic changes at the molecular level has resulted in a revolution in biology. Nowhere has this been more apparent than in the production of transgenic animals. Transgenic technology lies at the junction of several enabling techniques in such diverse fields as embryology, cell biology and molecular genetics. A host of techniques have been used to effect change in gene expression and develop new pharmaceutical and nutraceutical compounds cost-effectively. Scientific advances gained by transgenic capabilities enable further understanding of basic biological pathways and yield insights into how changes in fundamental processes can perturb programmed development or culminate in disease pathogenesis.

Animals↗
PubMed2004

Miniaturized, ultra-high throughput screening of tyrosine kinases using homogeneous, competitive fluorescence immunoassays.

Assay miniaturization and the implementation of high-density 1,536-microwell screening increase the speed and efficiency of screening and lead discovery. To serve this need, a platform of miniaturizable assay technologies has been assembled for specific biological targets. This platform will enable initiation and completion of uHTS screens in a straightforward and expeditious manner. Although faster primary screening does contribute to a reduction in timelines, the process of assay development can become a bottleneck. Assay technologies that do not require the use of target-specific reagents can reduce the time necessary for assay development. Assays that measure inhibition of tyrosine kinases can be configured in a competitive format where only the enzyme itself is specific to the assay. In this context, several technologies, including time-resolved fluorometry (also known as DELFIA), time-resolved fluorescence resonance energy transfer (also known as LANCE( trade mark )), fluorescence polarization, enzyme fragmentation complementation assay, and confocal laser scanning imaging, were examined. Quality parameters such as assay reproducibility, signal:background ratio, Z factor, and assay sensitivity were compared. Additionally, the relative merits of each of these technologies are assessed in terms of assay miniaturization, ease of development, ultimate screening capability, efficiency, and cost.

Amino Acid Sequence↗
PubMed2003

1,536-well assay development and screening using whole cell displacement binding and laser scanning imaging.

A screen of a GPCR against Pharmacopeia's combinatorial libraries was performed using 1,536-well plates in a 1.5-microl assay volume with an LSI that was specially modified to enable detection at these volumes. The screen encompassed approximately 4 x 10(6) compounds. The assay uses a CHO cell line that expresses human CXCR1. The plate format chosen was the Corning 1536 low-profile wafer plate. The performance of the screen is evaluated, and the necessity to obtain cytotoxicity data from the same well is described.

Animals↗
PubMed2003

Evaluation of compound interference in immobilized metal ion affinity-based fluorescence polarization detection with a four million member compound collection.

IMAP is a non-separation-based, antibody-independent, FP assay that can be applied to many types of protein kinases and phosphatases. This technology is currently being used in many high-throughput screening campaigns throughout the industry. In this technology, a fluorescently labeled peptide substrate is phosphorylated and then captured on immobilized metal (M(III)) nanoparticles, an interaction that is enhanced at low pH (pH 5.5). The binding of the phosphorylated peptide to the nanoparticles is detected using FP. IMAP differs from other FP formats in that the polarization signal is antibody-independent and involves metal coordination complexes detected at low pH. Here, this technology is evaluated against a 4000000-member compound collection using a 1536-well assay design that is devoid of enzymes so that only interference of the compounds with the detection system is measured. Miniaturization of the assay to 1536-well plates is discussed. Compound interference due to inhibition of phosphopeptide binding to the M(III) nanoparticles is not observed. Additionally, it is concluded that the level of fluorescence compound interference is similar to typical FP formats for the majority of the compound collection.

Combinatorial Chemistry Techniques↗