Screening secondary

Good secondary screens for ADME/Tox and selectivity. It used to be these were too expensive to consider at medium throughput, but this is... 

The layout of samples and controls configured on a plate during an assay. For example, for a primary screen in 384-well plates, columns 1, 2, 23, and 24 are controls, and columns 3-22 are for individual test compounds, whereas for secondary screening, each row will contain a single compound at varying concentrations. 

A screen applied to confirm independently actives from the primary screen. A secondary screen may employ an assay that differs in type from the primary screen, e.g., biochemical assay vs cell based assay, or it may be of the same type with different readout. 

HTS data and secondary screening for hit validation and determination of kinetic on/off rates. These data have been successfully incorporated into hit triage by enhancing the understanding of SAR differences between potential scaffolds [24]. In this example, those differences allowed informed decision making in the choice of which series to pursue and which to deprioritize. 

This chapter presents methods and protocols suitable for the identification and characterization of inhibitors of the prokaryotic and/or eukaryotic translational apparatus as a whole or targeting specific, underexploited targets of the bacterial protein synthetic machinery such as translation initiation and amino-acylation. Some of the methods described have been used successfully for the high-throughput screening of libraries of natural or synthetic compounds and make use of model universal mRNAs that can be translated with similar efficiency by cellfree extracts of bacterial, yeast, and HeLa cells. Other methods presented here are suitable for secondary screening tests aimed at identifying a ... 

The molecular weight distribution of a polymer produced with a chain shuttling catalyst/CSA system is highly dependent on reaction conditions. The extent of reversibility with the catalyst/CSA pairs was therefore further explored through a series of polymerizations over a range of monomer conversions (i.e., yield). A representative example from this secondary screening process is described below for precatalyst 17. Several members from this well-studied bis(phenoxyimine)-based catalyst family [39] were identified as poor incorporators in the primary screen. A series of ethylene/octene copolymerizations using 17 was performed across a... 

Successful candidates, that show high affinity towards the isolated PTK move to (2) secondary screening in which the compound is tested for its potency in... 

Figure 11.23 Comparison of a 384-parallel single-bead reactor and a 48-parallel secondary screening reactor for a set of reference catalysts in a partial oxidation reaction.

After primary screenings, which are less quantitative than biological assays giving a positive result or HIT , another more precise secondary screening is conducted, by calculations of IC50 values. 

Obviously, no solvent satisfies all these requirements, and the selection of a desirable solvent involves a compromise between these and other factors. When a preliminary selection has been made, a secondary screening can be performed based on simplified calculations of minimum energy requirement, since the capital costs for similar process configurations will not vary too much. 

Secondary screening provides the experimental means to weed out HTS hits, and provide HTS actives or validated hits, that is, compounds with known structure and activity (at this stage, dose-response curves are standard). 

Extracts that exhibited significant inhibitory activity, defined as >50% inhibition of CPE at 100 (xg/mL, were advanced into secondary screening, which includes confirmation of activity observed during the primary screen using an expanded range of concentrations (dose response), plaque inhibition assay, and a one-step growth inhibition and testing of additional influenza viruses. As shown in Fig. 1.2a, the quantitative dose response assay was used to assess the potency of the most two... 

Additional assays included a selectivity evaluation and cytotoxicity assay where both good selectivity and low cytotoxicity were documented. The extract was also tested on unrelated viruses and other influenza viruses. Extract A4 was the only one to maintain the activity through secondary screening, and with that as a target, purification of the active extract commenced. 

A secondary screen for compounds that bind non-covalently to estrogen receptor (ER, MW 67 kDa) was evaluated and illustrated for 17yS-estradiol (Ka 1 nM,... 

Hits obtained in the primary screens of 80 compound mixtures (see Section 23.2.2) were rerun in the secondary screens as singletons. 

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