Biological methods bioassays

More recently, measurements based upon the use of specific biological methods (bioassays) have become more validated and widely used. Biological measurement systems have significant advantages over chemical specific analytical test methods which cannot measure actual biological effects. 

As for the methods of analysis, the regulation considers biologic methods (bioassay in mice and in rats) and alternative methods [high performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS), and phosphatase inhibition]. When the results of the analyses performed demonstrates discrepancies between the different methods, the mouse bioassay should be considered as the reference method. 

It is obvious from the provisional risk assessment values for microcystins, and, being of the same order of magnitude of mammalian toxicity, similar values may be calculated for the cyanobacterial neurotoxins, that sensitive detection methods are required to detect these low concentrations of toxins. Of the biological methods of detection discussed earlier, the mouse and invertebrate bioassays are not sensitive enough without concentration of water samples, in that they are only able to detect mg of microcystins per litre. Only the immunoassays (ng-/rg 1 and the protein phosphatase inhibition assays (ng O... 

Concentration techniques, applied to assign priority pollutants, function as an interface between the environment, chemical analysis, and bioassays. The transition of harmful pollutants in an environmental system to multicomponent concentrates derived from that system is the principal challenge of concentration techniques aimed at the assignment of organic priority pollutants. A compatible combination of chemical and biological methods must be used. These methods can vary from the development of analytical procedures based on the observed biological activity of fractions of an environmental concentrate to the toxicological... 

The reasons why natural products have not been an area of focus for pesticide company discovery efforts are several. They include the relatively high cost of bioassay-directed isolation, the probability of rediscovery, and the often prohibitively complex structure of the active molecule. Furthermore, the strategies for discovery of natural product-based pesticide discovery are different from those for synthetic compounds, requiring a somewhat different laboratory infrastructure. New methods, including semi-automated bioassays, automated chemical extraction and analysis, and molecular biology methods to... 

Biological assay (bioassay) is the process by which the activity of a substance (identified or unidentified) is measured on living material e.g. contraction of bronchial, uterine or vascular muscle. It is used only when chemical or physical methods are not practicable as in the case of a mixture of active substances, or of an incompletely purified preparation, or where no chemical method has been developed. The activity of a preparation is expressed relative to that of a standard preparation of the same substance. Biological standardisation is a specialised form of bioassay. It involves matching of material of unknown potency with an International or National Standard with the objective of providing a preparation for use in therapeutics and research. The results are expressed as units of a substance rather than its weight, e.g. insulin, vaccines. 

The current efforts on electrochemistry with nanopartides have been reviewed with a certain bias towards the contemporary areas of research namely, electrochemical charging, sensors and the use of spectroelectrodiemical methods. There are many outstanding issues that require the attention of electrochemists in the years to come. Understanding the biological processes, bioassays and the stability of biomolecules under potential control is an area that is of immediate relevance. Mirkin and co-workers [10b] and Alivisatos and co-workers [9, 10a] have made significant contributions in the bioassembly of nanopartides and their optical properties. The electrochemistry is still not well explored. Potential-dependent... 

Sprague, J.B. (1973) The ABCs of pollutant bioassay with fish. In Biological Methods for the Assessment of Water Quality, Cairns Jr, J. and Dickson, K.L. (eds), pp. 6-30, STP 528. American Society for Testing and Materials, Philadelphia, PA. 

A series of mouse bioassay procedures (biological methods), differing in the test portion (hepat-opancreas or whole body) and in the solvents used for the extraction and purification steps, can be used for detection of the toxins DSR Sensitivity and selectivity depend on the choice of the solvents used for the extraction and purification steps, and this should be taken into account when making a decision on the method to be used, in order to cover the full range of toxins. 

There have been many biological methods developed for cyanotoxins that use the bioactivity of these toxins, such as potent hepatotoxicity, neurotoxicity, cytotoxicity, enzymatic activity, and immunological interactions. All these methods, although they are useful for sensitive screening of cyanotoxins, cannot detect and quantitate individual cyanobacterial toxins. Bioassays are recommended if any of these conditions are fulfilled [5] ... 

Hamasaki, K., Kogure, K., and Ohwada, K. 1996. A biological method for the quantitative measurement of tetrodotoxin TTX Tissue culture bioassay in combination with a water-soluble tetrazo-lium salt. Toxicon 34, 490-495. 

Previous work by Assem (1977) had suggested that the leucocyte histamine release test was a particularly useful diagnostic tool in patients who developed reactions to muscle relaxants. In that work, it was essential to assay the histamine released by a non-biological method (i.e., not on isolated guinea-pig ileum) because of the interference by muscle relaxants with the bioassay. The assay procedure used was chemical, using an automated spectrofluorometric technique (Technicon). Good... 

Bioassay methods Bioassays are procedures that can determine the concentration of purity or biological activity of a substance such as vitamin, hormone, and plant growth factor [19]. They measure the enzyme under the influence of a vitamin and the phenotypic effects of their deficiency [18]. Bioassay methods are rarely used clinically for vitamin analysis they are most commonly used for the analysis of vitamins B12 and D [20]. There are two types of bioassays ... 

Mouse Bioassay. The mouse is the traditional animal of choice for detecting biological activity due to STX and TTX. Mice receive an intraperitoneal injection of sample and are observed for symptoms of intoxication, i.e., dypsnea, convulsions, and death. This method is effective for detecting biological activity of STX and TTX in numerous samples. For the standard STX assay, one mouse unit is defined as that quantity of STX injected i.p. in 1 ml solution that will... 

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