Plague assay

Isotope dilution involves isotopes of the same element, thus eliminating differences in chemical behavior that can plague techniques that use different elements for the spike than the one being analyzed. This, along with the fact that quantitative recovery is not necessary once spike and sample have been equilibrated, makes isotope dilution less subject to error arising in chemical processing than many elemental assay techniques, a fact of great importance at low concentration levels. 

While the attributes of a drug-like profile are in no way to be minimized, the first and foremost properties for a proposed test series during early drug discovery is certainly their assay-likable profile - that is, if it cannot be tested you will not get a result, or even worse, one may perceive that one has an inactive compound and thus erroneously derive a negative SAR data point. Indeed, for the case of esmolol, the entire discovery process was almost halted when its first two series of target compounds were either too insoluble or too plagued by ISA, to be able to be effectively screened. 

Another major problem that has plagued the field of thymic hormone research is that specific bioassays for thymic hormones are not available. Indeed, the thymic hormones have been aptly termed hormones in search of a bioassay (Bach and Carnaud, 1976). It is quite simple to add a thymic factor to a routine immune assay and look for a positive or negative influence. However, unless the target cell population for such studies is well defined, the results are likely to be difficult to interpret in terms of normal physiological mechanisms. This latter point no doubt explains many of the inconsistencies reported in the thymic hormone field. 

It is not possible to conduct meaningful investigations of the electronic or molecular properties of crystals unless detailed knowledge of their chemical and physical constitution is available. Inorganic azides research continues to be plagued with samples containing impurities whose significance is difficult to ascertain. However, apart from their tendency to explode or decompose prematurely in, for example, the sample chamber and source of mass spectrometers, the chemical analysis of research samples of azides presents no special problems, and the determination and assay of azides in various media is described in Volume 2, Chapter 2. 

Y. pestis in experimentally infected fleas and monkey blood and oropharyngeal swabs. The signal is detected and interpreted by the ABl 7700 Sequence Detector (Applied Biosystems, Foster City, Calif.), a combination of thermal cycler, laser, and detection per software system [60]. (c) PCR-based assay, with FRET registration, was used to detect ciprofloxacin-resistant (CpO mutants of plague. It was possible to distinguish the wild type from antibiotic-resistant type, and detect approximately 10 pg of DNA (or 4 CFU, colony forming units) of wild-type F. pestis KIM 5 or Cp mutants in crude lysates [61]. 

Serologic assays measuring the immune response to plague infection are mainly of value retrospectively, since patients present clinically before they develop a significant antibody response. Enzyme-linked immunosorbent assay (ELISA) tests and the older, less-sensitive passive hemagglutination as-... 

Williams JE, Gentry MK, Braden C A, Leister F, Yolken RH. Use of an enzyme-linked immunosorbent assay to measure antigenaemia during acute plague. Bull WHO. 1984 62(3) 463-466. 

This study illustrates several potential advantages SERS possesses over other widely used biomedical spectroscopic tools such as fluorescence. For example, no fluorescent reporter molecule is needed for SERS, eliminating an assay step, thereby reducing assay time and cost. Additionally, the analyte-specific SERS spectrum may allow discrimination between specific binding to the assay substrate and nonspecific binding, which often plagues sandwich-type iimnunoassays. 

At least in academia, HTS capacity is generally limited. In many instances, VS is the only available approach to search for new active compounds. Furthermore, in cases where assays are difficult, time consuming, and/or expensive and hence not straightforward to format for HTS, VS presents a fast and comparably cheap alternative. It is evident that HTS as an individual discipline has not solved the bottlenecks of drug discovery, despite massive investments. Many HTS campaigns are plagued with false-positives and hit sets that are often difficult to deconvolute. There are a number of examples where VS has identified first-in-class active compounds including cases... 

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