Surrogate assays

Thus drug discrimination can serve as an in vivo surrogate assay for receptor activation where the cne is selective for a particular receptor. It is a selective and sensitive in vivo measnre of nenronal and receptor mechanisms and can help researchers to understand more of the brain s fundamental processes. It is the only assay allowing a direct test in which subjects that do not have language (e.g. rodents) can detect the presence of a psychoactive substance in the body and define the extent of the similarity of its effects to those of other substances. 

Fig. 4.4. A typical surrogate assay for a mammalian receptor in yeast cells.

The numbers and structures of potential candidates are enormous, so that surrogate assays have been developed. The in vitro assays that have been considered and evaluated have been reviewed (Zacharewski 1997 Anderson et al. 1999), and in environmental studies several assays have been most generally used. 

In summary, as with all surrogate assays, care must be exercised by taking into account the sensitivity of different assays, their intrinsic variability, and the possibly cardinal issue of metabolism. 

Higher-Throughput Surrogate Assays for Quantifying the Potential for Bioactivatirai 528... 

For each of these TCPs, a test cascade has been established that captures the phase Ila, phase Ib, and predinical (candidate, late lead, early lead, validated hit, and screening hit) criteria. Critically, the predinical assays are as closely aligned to the chnical end points as possible, in terms of human-relevant tissue and pathogen. However, as is true for P. vivax in particular, the biology is not sufficiently mature and surrogate assays are commonly used because of the complexities of accessing parasite biomass. The specific test cascades have been documented in several key articles [15,16]. 

Surrogate screening (utilizing similar but not exact therapeutically relevant targets) can lead to dissimulation in screening data, especially for allosteric molecules. For this reason, frequent reality testing with a therapeutically relevant assay is essential. 

Instead of using surrogate measures for oral absorption with a lipophilicity or permeability assay in vitro, oral absorption can also be estimated in silica by using... 

Sompuram SR, Kodela V, Ramanathan H, et al. Synthetic peptides identified from phage-displayed combinatorial libraries as immunodiagnostic assay surrogate quality-control targets. Clin. Chem. 2002 48 410-420. 

An important concept in this approach is that the actual assays, or combinations of the assays, may be surrogates for a far larger set of targets of interest. This principle... 

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