Animal assays

Differences in the equilibrium dissociation constant, K, for the binding of the various saxitoxins to the sodium channel binding site largely determine the differences in the potencies of the toxins in whole animal assays and in tissue preparations. 

Compared to animal assays, CTA is faster and cheaper. In vitro CTAs have been shown to involve a multistage process that closely resembles some stages of in vivo carcinogenesis and have the potential to detect both genotoxic and non-genotoxic carcinogens. 

Magnusson, B. and Kligman, A.M., The identification of contact allergens by animal assay. The guinea pig maximization test, J. Invest. Dermatol., 52, 268, 1969. 

The recognition of their structure permits the determination of vitamins by the tools of analytical chemistry, but while such methods are widely used in industrial production, the minute quantities in body fluids and tissues limit the purely chemical approach to a few members of this group present in relatively high concentration, e.g., vitamin C (K5). Microchemical methods are in use for the determination of thiamine, riboflavin, and some of the fat-soluble vitamins, based on the most sensitive colorimetric and, in particular, fluorometric techniques. Vitamin D, on the other hand, is determined by animal assay. 

Law 480 blends corn-soy and corn-soy-milk, with respect to protein quality by animal assay, organoleptic quality and storage... 

Three animal procedures (protein efficiency ratio, net protein ratio, and protein digestibility) were used to evaluate protein quality. The AOAC (13) animal assay for protein efficiency ratio... 

Butterweck V, Wall A, Lieflander-Wulf U, Winterhoff H, Nahrstedt A. (1997). Effects of the total extract and fractions of Hypericum perforatum in animal assays for antidepressant activity. Pharmacopsychiatry. 30(suppl. 2) 117-24. 

The Animal Testing Ban prohibits the use of in vivo animal assays in the EU to meet the requirements of the Cosmetics Directive for finished products (since 11 September 2004) and ingredients/ combinations of ingredients (gradually with the validation and adoption of alternative methods up to a strict prohibition as of 11 March 2009). 

Scientists were faced with formidable experimental challenges in trying to determine which compounds were responsible for this biological activity. Not only are they present in trace amounts and in chemically very complex mixtures of airborne POM, but in vivo animal assays for suspected new genotoxic and carcinogenic agents were then, and remain, time-consuming, labor intensive, and expensive. 

Extrapolation techniques may permit the estimation of upper limits of risk to human populations. To do so, data are needed to estimate population exposure valid, accurate, precise, and reproducible animal assay procedures are required and appropriate statistical methods are necessary. 

PER is a method to metabolize or determine the quality of protein in foods. Quality is measured by the amount of usable protein and the growth resulting from it through an animal assay. Formerly, this method was used as the standard method for all protein quality analysis. However, there is some question as to whether or not it is a valid measurement. This is because PER does not account for the differences in amino acid requirements between humans and rats (Seligson and Mackey, 1984), nor does PER account for the protein needed for cell maintenance. Therefore, PER results often overestimate the requirements for some amino acids and underestimate others. Specifically, PER tends to underestimate the protein quality of lysine-deficient proteins such as wheat gluten (Hackler, 1977). 

EXTENSIONS AND COMMENTARY I know of no record of 2C-H ever having been tried by man. It has been assumed by everyone (and probably correctly so) that this amine, being an excellent substrate for the amino oxidase systems in man, will be completely destroyed by the body as soon as it gets into it, and thus be without action. In virtually all animal assays where it has been compared with known psychoactive drugs, it remains at the less-active end of the ranking. 

Animal assays. When assessing the nature of a protein quality reduction, the conventional methods of protein quality measurement have certain limitations. For example, a reduced TD in an NPU assay is not necessarily the result of a reduced protein digestion. Obviously the same result will be obtained if the increase of fecal nitrogen is caused by an enhanced excretion of endogenous protein or if there is a fixation of metabolic nitrogen by the colonic micro-flora. 

Genotoxicity. No studies were found on the genotoxic effects of chlorobenzene in humans by any route of exposure. Results of animal assays were mixed. Chlorobenzene induced statistically significant increases in polychromatic erythrocytes containing micronuclei in mice following... 

The assay used throughout the development of cimetidine was an animal assay on anesthetized rats. The rats were treated with histamine (11.36) to stimulate acid secretion. The same rats were then treated with a potential antagonist. Increases in stomach pH caused by administration of the antagonist were monitored to screen for activity. 

Unmodified lysine is, in principle, biologically available and will be determined as such by animal assays (21) and enzymatic methods (22, 23,24), or determined as reactive lysine by the Carpenter method (23,24,25, 26) and by guanidina-tion (24, 27). 

The hypothesis of the loss of lysine availability engaged in such peptides has been tested in animal assays with the free synthetic molecules. 

These are animal assays that evaluate the ability of chemicals to produce cumulative irritation. Many such tests have been described in literature, but only a few have been studied extensively enough to mention. Even those used more often are not as well standardized as Draize-type tests, and many variables have been introduced by multiple investigators. 

The authors interpreted the results as follows FK224 is a dual NK, /NK2 antagonist in a variety of animal assays however, the reported affinities are quite low (substance P-induced contraction of guinea-pig ileum, pA2 6.88 NKA-induced contraction of rat vas deferens, pA2 7.50). These data suggest that the dose of FK.224 used in the clinic may have been too low to effectively block neurokinin receptors in the airways and casts doubt on the interpretation of the earlier bradykinin study. 

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