Bioassays, quantitative

Scanning Electron Microscopy and X-Ray Microanalysis Principles of Electroanalytical Methods Potentiometry and Ion Selective Electrodes Polarography and Other Voltammetric Methods Radiochemical Methods Clinical Specimens Diagnostic Enzymology Quantitative Bioassay... 

Nomura and Ogata provided the first evidence that tunicates can produce PGs [17]. Using a rat stomach fundus bioassay, Halocynthia roretzi tissues were shown to possess low levels of PGs. The testes showed higher levels (9 ngg-1 wet tissue) than ovary and muscle tissue. The sea-squirt Styela clava did not show PGs by this method. No structures were determined in this work. Reexamination of the ability of H, roretzi to produce PGs was carried out by Ogata and coworkers [19]. Incubation of selected tissues with 14C-labeled eicosa-8,11,14-trienoic acid and subsequent isolation of PGE and PGF fractions after addition of carrier showed the branchial tissue to have the highest conversion levels. Quantitation was done by LSC. Using a TLC radioscanner, the authors determined that fractions with metabolites similar to PGE and PGF... 

X. Zhao, L.R. Hilliard, S.J. Mechery, Y. Wang, R.P. Bagwe, S. Jin, and W. Tan, From the cover a rapid bioassay for single bacterial cell quantitation using bioconjugated nanoparticles. Proc. Natl. Acad. Sci. U.S.A. 101, 15027-15032 (2004). 

Bioassays represent the most relevant potency-determining assay, as they directly assess the biological activity of the biopharmaceutical. Bioassay involves applying a known quantity of the substance to be assayed to a biological system that responds in some way to this applied stimulus. The response is measured quantitatively, allowing an activity value to be assigned to the substance being assayed. 

One of the most popular bioassay for interferons is termed the cytopathic effect inhibition assay . This assay is based upon the ability of many interferons to render animal cells resistant to viral attack. It entails incubation of the interferon preparation with cells sensitive to destruction by a specific virus. That virus is then subsequently added, and the percentage of cells that survive thereafter is proportional to the levels of interferon present in the assay sample. Viable cells can assimilate certain dyes, such as neutral red. Addition of the dye followed by spectrophotometric quantitation of the amount of dye assimilated can thus be used to quantitate percentage cell survival. This type of assay can be scaled down to run in a single well of a microtitre plate. This facilitates automated assay of large numbers of samples with relative ease. 

The quantitation of a protein that has a specific biological function, a hormone, for instance, may not give a true indication of its biological activity owing to the inactivation of some of the protein. For proteins that have definite biological functions the choice is between chemical quantitation and bioassays. For this reason the catalytic activity of an enzyme is more frequently measured than is its protein concentration. 

In addition to its use in quantitating the product, ELISA can also be used as a readout tool for cell-based bioassays or other assays that measure a biological activity conferred by the drug product. The end point of the bioassay may be a... 

Quantitative analysis of feverfew with regards to sesquiterpene lactone content has been carried out by TLC [72,73] and HPLC [71,74,75] and H-NMR spectroscopy [75]. Measurements of parthenolide by HPLC correlated well with measurements by bioassays based on 5HT-secretion from platelets [75]. The availability of several techniques for quantitation of parthenolide levels in feverfew, makes some standardization of commercial preparations possible. 

Having briefly defined these four endpoints, I would like to ask, Are they related to known human disease Can they be measured quantitatively and Can they be measured with facility for inclusion in an overall plan for environmental bioassay Table I lists examples of gene locus mutations resulting in human disease phenylketonuria, histidinemia, Hartnup disease, and cvstinuria. Phenvlketonuria is... 

Although there are limitations, as Indicated previously, the described bioassay appears to be an efficient method to evaluate the phytotoxlclty of various samples, both qualitatively and quantitatively. 

Absorption, Distribution, Metaboiism, and Excretion. There is relatively little quantitative information on the systemic absorption of inhaled carbon tetrachloride in animals and humans, with estimates ranging from 30% to 60% (Lehmann and Schmidt-Kehl 1936 McCollister et al. 1951). In order to confirm the dose absorbed during inhalation exposures to carbon tetrachloride, it would be useful to determine the systemic uptake of carbon tetrachloride in additional animal experiments, with special attention to concentration- and time-dependency of absorption. It may be useful to conduct short-term studies of the relative absorption, disposition, and toxicity of inhaled versus ingested carbon tetrachloride. Such studies can yield information pertinent to route-to-route extrapolation and may be more economical than conducting a 2-year inhalation cancer bioassay of carbon tetrachloride. 

The infralaboratory calibration study was performed by the Institute for Environmental Studies. Sediment was extracted and cleaned up as indicated here. The determination of dioxin and/or dioxin-like content was according to the method indicated under the section DR CALUX analysis. For the intralaboratory study, the following parameters were investigated limit of detection (LOD), limit of quantitation (LOQ), and reproducibility and repeatability of the bioassay. 

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