Functional bioassays assays

Fig. 5.17 Demonstration of MS-based bioassay functionality using a plant extract. MS instrument Ion-trap mass spectrometer (LCQ Deca, Thermo Electron), (a) MS analysis of pure extract by direct injection onto restricted-access column 2 in the absence of affinity protein, (b) Analysis of the same natural extract spiked with digoxin using the label-free MS assay method as shown in Fig. 5.15.

Cytokines, which are protein mediators produced by immune cells, are involved in the regulation of cell activation, growth and differentiation, inflammation, and immunity. Measurement of cytokine production, as determined by techniques such as bioassay, radioimmunoassay, and enzyme-linked immunosorbent assay, has been used to examine various immune functions. 

The most relevant bioassays measure specific activities on immune function, either as effector or regulatory, for example, assay of cytokine IL-12 by the augmentation of the cytolytic function of natural killer cells (B9), IL-10 by the inhibition of the production of TNF-o from stimulated monocytes (B13), and IL-8 and eotaxin by the chemotaxis of neutrophils and eosinophils, respectively (C2). 

The study of potential paracrine modulators (estrogens, androgens and growth factors) that could enhance FSH action led to the development of an in vitro granulosa cell aromatase bioassay (GAB). The combined action of enhancing hormones and factors resulted in an assay highly sensitive to the aromatase-inducing function of FSH [69], This assay is hormone-specific and sensitive, and has been applied to the measurement of FSH bioactivity in serum [70] and urine samples [71] from humans and diverse animal species. 

Out-of-the-box HTS informatics software solutions with integrated functionality of all three operational components (HTS data, plate and sample tracking, chemical structures) include ActivityBase from IDBS, Assay Explorer from Symyx (former MDL), BioAssay Enterprise from CambridgeSoft, Accord Enterprise (Accelrys), Chemlnnovation (CBIS), and others. However, we recommend careful evaluation of functionality, usability, architecture, and availability of a published application programming interface (API) if the system is to be integrated with other informatics components. Because the commercial solutions have different strengths, one answer is to combine different components or build certain functionalities in-house. 

To investigate whether bevirimat functions as a PR inhibitor, several bioassays were conducted, including a cell-free fluorometric assay using a synthetic peptide substrate of PR and experiments using a recombinant form of the Gag precursor protein Pr55Gag. Both assays showed no effect of bevirimat on PR function compared with the PR inhibitor indinavir. Indeed, bevirimat at nanomolar concentrations could inhibit the replication of HIV-1 isolates resistant to PR inhibitors. 

Bioassay A biological assay, or bioassay, is an analytical procedure capable of measuring the biologic activity of a substance based on a specific functional, biologic... 

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