Response data, interpretation

FIGURE 5.56 The threshold region for chronic dose-response curves. [Reprinted with permission from Tardiff, R.G., and Rodricks, J.V. (1987). (Eds.), Toxic Substances and Human Risks Principles of Data Interpretation. New York Plenum Press.]... 

The defect question delineates solid behavior from liquid behavior. In liquid deformation, there is no fundamental need for an unusual deformation mechanism to explain the observed shock deformation. There may be superficial, macroscopic similarities between the shock deformation of solids and fluids, but the fundamental deformation questions differ in the two cases. Fluids may, in fact, be subjected to intense transient viscous shear stresses that can cause mechanically induced defects, but first-order behaviors do not require defects to provide a fundamental basis for interpretation of mechanical response data. 

The situation becomes bleaker still when we recognize that, for a given substance, there may be many different conditions A under which its adverse effects and their dose-response characteristics have been investigated Results may be available from several different epidemiological studies, in different groups exposed under different circumstances, and with results that are not entirely consistent with each other. Some of the conditions may involve experimental data, similarly variable in outcome and in how they will be interpreted by different scientists. So, when we are faced with toxic hazard and dose-response data from studies involving conditions A1 through A12, which, if any, are most useful and relevant for extrapolation to condition B ... 

Historical control data is an essential component of the study directors toolbox for interpreting reproductive and developmental toxicity data. Scientific judgment and expertise should be used to determine if historical control data is needed for interpretation of study data, which historical control data is appropriate, and how it should be used to support interpretation of a finding. This tool can be a valuable addition to a comprehensive assessment of the study data, which includes determining whether a dose-response is present and whether any statistically significant findings occurred. Sound data interpretation requires that the litter, not the fetus or pup, be used as the experimental unit in developmental and reproductive toxicity studies. For continuous data (e.g., fetal weight). 

As noted earlier, the interpretation of plasma level versus clinical response data even in well-designed studies is further complicated by the presence of multiple... 

Many starfish cause an escape response in usually sessile marine invertebrates [7]. The starfish Dermasterias imbricata causes the sea anemone Stomphia coccinea to release its basal disc from the substratum and swim away on contact. Bioassay-directed fractionation of the starfish extract led to the isolation of the compound found to elicit this response, the benzyltetrahydroisoquinoline alkaloid imbricatine (646). The structure of compound 646 was elucidated by spectral data interpretation. The amino acid residue in imbricatine is related to the thiol containing amino acids ovothiols A-C. Imbricatine (646) is active in both LI210 and P388... 

One of the functions of Global Core Technologies R D is the analytical discipline Reactive Chemicals/ Thermal Analysis/Physical Properties (RC/TA/PP). Some of the capabilities of this discipline are testing and data interpretation for reactive chemicals hazard assessment. It is the responsibility of the owner of any chemical process to use this Dow resource to obtain the information which is necessary to design a safe and efficient operation. Information about the analytical RC Testing discipline including contact names can be obtained on the INTRAnet at Reactive Chemicals/Thermal Analysis/Physical Properties web site. 

Pharmacokinetic models. An important advance in risk assessment for hazardous chemicals has been the application of pharmacokinetic models to interpret dose-response data in rodents and humans (EPA, 1996a Leung and Paustenbach, 1995 NAS/NRC, 1989 Ramsey and Andersen, 1984). Pharmacokinetic models can be divided into two categories compartmental or physiological. A compartmental model attempts to fit data on the concentration of a parent chemical or its metabolite in blood over time to a nonlinear exponential model that is a function of the administered dose of the parent. The model can be rationalized to correspond to different compartments within the body (Gibaldi and Perrier, 1982). 

Completing field documentation (Step 5), such as the Chain-of-Custody (COC) Form, field logs, and sampling forms, is a separate and distinctive step in the sampling process. Field documentation establishes the basis for informed data interpretation and efficient and accurate report preparation. The COC form is usually the only written means of communications with the analytical laboratory. It also serves a legal function by documenting the chain of individuals, who were responsible for sample integrity. 

If the mouse does not show a heightened response to the startle stimulus in the testing trials, it may have cognitive deficits. Memory should be examined in separate, specific tests to ensure accurate data interpretation. 

This disciplinary divide affected Meitner as well. As the team s physicist, she was the scientific leader of the project, responsible for interpreting all the results, more aware of its difficulties, and more troubled by what she did not understand. Yet she was dependent on the chemists for data and she could not dispute their radio-analytical methods or argue for a different chemical approach. As it happened, the Berlin team s most crucial error was that it focused on the transuranium precipitate only and, with few exceptions, did not search the filtrate for new activities. Later Meitner recalled,... 

The chapter is set out in the same order in which QSAR models are generally constructed starting with the selection of compounds for modeling, collection of response data, assembly of physicochemical descriptor data, data reduction, or selection, and the construction and interpretation of the models. 

A more detailed explanation about the use of tracer methods to evaluate contacting efficiency, the relationships needed to interpret tracer response data, the experimental methodology, and various results are given by Mills and Dudukovic (41). It suffices to say here that the following correlations based upon Reynolds and Galileo numbers were determined by El-Hisnawi to represent the available data on small porous packings in the trickle-flow regime ... 

ASSESSMENT OF RISKS TO HUMANS EXPOSED TO PESTICIDES 2 The Four Steps in Risk Assessment 2 Hazard Identification 2 Dose-Response Assessment 3 Margin of Safety Approach 3 Quantitative Risk Assessment 3 Exposure Assessment 4 Risk Characterization 4 RISK MANAGEMENT 5 ADVANCES IN DATA INTERPRETATION 5 Probabilistic Approaches 5 Recognition of the Tier Approach 5 Aggregate Exposure 6 Cumulative Exposure 6 Impact of New Scientific Advances 7 Post-Registration Monitoring 7 HARMONIZATION OF REGULATORY APPROACHES SUMMARY 9... 

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