Animal species determination

Animal Species Determination (Known Species With or Without Quantification)... 

Animal species determination in processed material or food products can be performed by PCR amplification of mitochondrial DNA followed by sequencing analysis of the product (see Chapter 6) or by RFLP. RFLP analysis can be successful only if the DNA detected is from a species with a known RFLP pattern. In addition, if DNA from only one animal is detected by sequencing analysis or RFLP, there is actually no guarantee that DNA from other species is also present at very low amounts. Low contaminations can also be detected by real-time PCR. For sequencing analysis or RFLP, PCR primers are used that amplify DNA from almost aU mammals. In contrast, for real-time PCR, primers specific for each species have to be used. 

DNA fragments (e.g., animal species determination), and sequence determination of difficult secondary DNA structures. 

Animal species determination in meat, processed material, or food products can be carried out by PCR amplification of mitochondrial DNA (mtDNA) followed by sequencing of the product by RFLP or real-time PCR (see Chapters 3 and 4). The structure of mitochondrial DNA is shown in Figure 6.6. The size of mtDNA can vary from 15,700 to about 20,000 bp in higher animals such as mammals, frogs, and insects. In the same species, differences of up to 900 bp can be observed [4]. 

Example 2 A costumer declared that hairs were found at the surface of a beef meat he bought from a self-slaughtering butcher. By animal species determination, canine DNA was identified. Since the butcher and the customer both owned a dog, samples were taken from both and mtDNA analysis was performed of the canine D-loop region. The two dogs showed different sequences, but only the customer s dog showed the same sequence as the hairs found on the meat. Therefore, the butcher s dog could be excluded as the source of the hairs. 

Heliantholysin. The major form of heliantholysin is a basic polypeptide chain (pi in the region of 9.8) having a molecular weight of 16,600. Its amino acid sequence has been determined (11). It is powerfully hemolytic for washed erythrocytes derived from a variety of animals, those of the cat being the most sensitive, and those of the guinea pig the most resistant (10). As is true of most hemolytic systems, the biochemical basis for the very large differences in sensitivity of erythrocytes from different animal species is unknown. 

No studies were located regarding toxicokinetic data in humans. Limited information is available regarding the toxicokinetic differences among animal species. Rats, mice, mink, and dogs showed rapid absorption, wide distribution, and over 90% urinary excretion of diisopropyl methylphosphonate or its metabolites. However, the rates of absorption and patterns of distribution varied (Hart 1976 Weiss et al. 1994). The mechanism of toxicity is also undetermined. From the limited data available, it is not possible to determine the degree of correlation between humans and animals. 

Comparative Toxicokinetics. There are no data on the kinetics of diisopropyl methylphosphonate in humans. Studies in animals suggest that metabolism and urinary metabolite profiles are qualitatively similar among species. Additional studies would be useful in understanding the differences in metabolic rates in species and in determining which animal species is the most appropriate model for human exposure. 

Soltes, L., Sebille, B. (1997). Reversible binding interactions between the tryptophan enantiomers and albumins of different animal species as determined by novel high performance liquid chromatographic methods an attempt to localize the d- and L-tryptophan binding sites on the human serum albumin polypeptide chain by using protein fragments. Chirality 9, 373-379. 

Based on rat neuropharmacokinetic concepts, it has been proposed [37,42,45] that Cb/U may be projected directly from Cp for large animal species (i.e., dog, monkey, and human) in which Cb are rarely measured. For such species, in which serial blood sampling is common for determining plasma pharmacokinetics, compound Cb,u may be extrapolated using its Cp, species-specific /u,p, and rat-derived Cb,u CP/U assuming a fixed ratio across species ... 

Developmental Toxicity. No information is available on developmental effects of acrylonitrile in humans by any route of exposure. Acrylonitrile is teratogenic and embryotoxic in rats both by the oral and inhalation routes of exposure. Developmental studies on other animal species have not been conducted. Because species differences for acute acrylonitrile toxicity and metabolism have been demonstrated, additional developmental studies in other species using various dose levels would be valuable in evaluating the potential for acrylonitrile to cause developmental effects in humans. Because the available oral study was conducted by gavage, additional studies are needed to determine if these effects will occur following ingestion of drinking water or food. 

Comparative Toxicokinetics. The absorption, distribution, metabolism, and excretion of acrylonitrile in rats has been studied. Limited work in other species suggests that important species differences do exist. Further evaluation of these differences, and comparison of metabolic patterns in humans with those of animals would assist in determining the most appropriate animal species for evaluating the hazard and risk of human exposure to acrylonitrile. 

For most chemicals, actual human toxicity data are not available or critical information on exposure is lacking, so toxicity data from studies conducted in laboratory animals are extrapolated to estimate the potential toxicity in humans. Such extrapolation requires experienced scientific judgment. The toxicity data from animal species most representative of humans in terms of pharmacodynamic and pharmacokinetic properties are used for determining AEGLs. If data are not available on the species that best represents humans, the data from the most sensitive animal species are used to set AEGLs. Uncertainty factors are commonly used when animal data are used to estimate minimal risk levels for humans. The magnitude of uncertainty factors depends on the quality of the animal data used to determine the no-observed-adverse-effect level (NOAEL) and the mode of action of the substance in question. When available, pharmocokinetic data on tissue doses are considered for interspecies extrapolation. 

Acquisition of data on organotin toxicokinetics, including data on routes of exposure, uptake, retention, and translocation. Studies should emphasize whole organisms to determine if food chain biomagnification is a potential problem reproductive organs, in which organotin burdens may affect proliferation and edible tissue, especially muscle and liver, which are selectively consumed by humans and various animal species (WHO 1980 Reuhl and Cranmer 1984 Wilkinson 1984 Hall and Pinkney 1985 Thompson et al. 1985). 

Allometry Determinants of VD (e.g., tissue and blood volumes binding capacity) scale with body weight across species VDSS in two or more animal species [2-5]... 

PBPK modeling is the development of mathematical descriptions of the uptake and disposition of chemicals based on quantitative interrelationships among the critical biological determinants of these processes. These determinants include partition coefficients, rates of biochemical reactions and physiological characteristics of the animal species. The biological and mechanistic basis of the PBPK models... 

We believe that the concentration of volatile solids in the digested substrate is fundamental and that an optimum (to be determined) exists for each animal species. 

Topical formulations are another special case. Over time, it has been shown that the minipig has a skin structure that is quite similar to humans, and that species is now used commonly as the nonrodent model. These types of formulations also require local irritation studies where guinea pigs are used to determine delayed contact sensitization. Selection of the animal species for the nonclinical program is often not straightforward. 

Without the availability of animal dafa, how would one decide on the first dose of a molecule (that has never been administered to any animal) to be given to man A frequently used method is to give a volxmteer 10% of the lowest no-effect" dose seen in two or three animal species. How would one decide on the route of administration Some compounds are very toxic to intact veins. How could one give reasonable assurance of safety of a new chemical never before administered to a human The only viable option is to determine tolerance in the veins of lower animals before moving to a volxmteer. Should animal activists not have to put forth their actual protocol for studying a new drug candidate in humans How would they answer the questions raised above ... 

Immunotoxicity. No information was located on the immunological effects of bromomethane in humans or animals exposed by any route. A battery of immune function tests in several animal species exposed to bromomethane by the inhalation and the oral routes would be valuable in determining if the immune system is adversely affected, and if so, in determining species and route specificity, as well as the threshold for those effects. 

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