Choice of species

A reaction dataset, such as the LLNL database, provides an alternative method for balancing reactions. Such a database contains reactions to form a number of aqueous species, minerals, and gases, together with the corresponding equilibrium constants. Reactions are written in terms of a generic basis set B, which probably does not correspond to set B, our choice of species to appear in the reaction. 

Choice of Species. A bewildering variety of exogenous systems have been used for one purpose or another in mutagenicity tests. The choice begins with plant or animal preparations. The attraction of plant systems has stemmed from a desire to avoid the use of animals, where possible, in toxicity testing. In addition, plant systems have particular relevance when certain chemicals are being tested, for example, herbicides. 

The choice of species and strain to be used in a carcinogenicity study is based on various criteria including susceptibility to tumor induction, incidence of spontaneous tumors, survival, existence of an adequate historical data base, and availability. 

As noted earlier, the choice of species for experimentation is critical due to anatomical differences and it may also reflect species, as well as individual, differences in the expression/activity of transporter and metabolic proteins [43, 44], Since the fraction absorbed across buccal mucosa in vivo is not established for many compounds in different species including humans, the potential existence of a correlation between in vitro permeability coefficients in freshly isolated pig, dog, monkey, and human buccal mucosa was investigated (Figure 7.3). The correlation coefficient obtained for porcine and canine tissue was poor (0.65 and 0.67, respectively, at the 95% confidence level). Results for relatively high permeability compounds in porcine tissue resemble those previously reported where permeability coefficients were by an order of magnitude... 

Tables 3.25-3.27. As there is considerable diversity in the choice of species, route of administration, and time after injection in these studies, depleting...

The animal species chosen for the later nonclinical safety studies should be responsive to the pharmacodynamic action(s). If the standard laboratory species are not responsive, the applicant should justify the choice of species selected or any supplementary tests if these are deemed appropriate. 

The approach "select favorable raw material has a major impact on the selection of pretreatment processes. For example, the poplar responds splendidly to many pretreatments that fail with Douglas fir or pine-based materials (I). Specific tissues and cells of a given biomass raw material will respond quite differently. For example, the rind fiber of sugarcane bagasse behaves quite differently from the pith fiber (11)- In woody species, the selection of tissues low in bark and extractives is an important factor in the ease or resistance to cellulose hydrolysis. Before embarking on development of processes for hydrolysis of a biomass resource, it is highly desirable to exercise discretion with respect to the choice of raw materials at both the species and tissue levels. This idea is all the more important in an initial choice of species and pretreatment process. 

A total of 45 different species were employed, but authors did not always specify their choice of species. Ideally, bioassays should have some basic characteristics, as defined by Giesy and Hoke (1989). An adequate battery of bioassays needs in principle to measure various types (acute, chronic, genotoxic) and levels (lethal, sublethal) of ecotoxicity, without any redundancy, with test species belonging to different trophic levels or characterized by different ecological and biological traits (Ducrot et al., 2005). Another important aspect in the selection of bioassays for a test... 

With some enzymatic reactions, both substrate and product may be readily measured, so that reactions may be followed by measuring either the depletion of substrate or the accumulation of product. The optimum choice of species for measurement then depends on the measurable properties of the substrate and product and on the measurement technique employed, so that a comparison of sensitivities and detection limits is necessary. 

Primates may be needed when it becomes clearer that the parameters of interest (hematology, blood chemistry, histopathology, etc.) can only be studied in species that are phylogenetically closer to H. sapiens. This is often the case when candidate drugs are proteins (e.g. animal-derived monoclonal antibodies), and antibody formation may be major issue and may dictate the choice of species. For example, it may be known that only the chimpanzee does not develop neutralizing antibodies to the drug, which would lead one to select that species as the nonclinical model. 

During the first planting season, seed and revegetate, considering time and method of seeding and choice of species. 

Details of the determinants for repeated exposure studies, and the choice of species, dosing... 

For foUow-up testing, the choice of species should take previous data into consideration (e.g., organ-specific generation of DNA-reactive metabolites, tumor findings, etc.). 

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