Category/read-across

Enoch SJ, Cronin MTD, Madden JC, Hewitt M (2009) Formation of structural categories to allow for read-across for teratogenicity. QSAR Comb Sci 28(6-7) 696-708... 

When analog data are used to fill the data gaps for one or more endpoints, the data for the analogs must be compared and discussed in relation to the substance under evaluation in order to shed light on the similarities and differences in the Toxicological Profile of the substance under evaluation and its analog(s). If the available test results show that the substances in a category behave in a similar or predictable manner, then read-across can be used to assess the substance for which no data on a specific endpoint are available. 

In addition to the use of (quantitative) structure-activity relationships and read-across (see Section 2.1.1), category approaches for grouping substances according to structural activities are being developed under RIP 3.3. 

Normally grouping involves collecting chemicals and establishing if they can form the basis for read-across or category because of some measure of commonality. 

To obtain the air stability category, refer to Table 2-1. Enter Table 2-2 with the category obtained from Table 2-1. Select the appropriate weather and terrain conditions from Table 2-2. Read across to where the columns intersect and extract the final stability category. For more information on field expedient behavior of chemical agents, see FM 3-6 or from CDM. 

Enoch SJ, Cronin MT, Ellison CM (2011a) The use of a chemistry-based profiler for covalent DNA binding in the development of chemical categories for read-across for genotoxicity. Altem Lab Anim 39, 131 5. 

Hewitt M, Enoch SJ, Madden JC, Przybylak KR, Cronin MT (2013) Hepatotoxicity a scheme for generating chemical categories for read-across, structural alerts and insights into mechanism(s) of action. CritRev Toxicol 43, 537-58. 

This information may derive from laboratory testing. Alternatively, toxicologists may predict hazards from a structure-activity relationship (SAR), which is "the relationship of the molecular structure of a chemical with a physicochemical property, environmental fate attribute, and/or specific effect on human health or an environmental species. These correlations may be qualitative (simple SAR) or quantitative (quantitative SAR, or QSAR)" [79, p. 1]. Both "read across" from the behavior of one chemical to that of a similar chemical and the practice of assessing chemicals by categories are forms of SAR [80,81]. 

ECHA. 2009. Practical Guide 6 How to Report Read-Across and Categories. Available... 

Aging and Vulnerability to Environmental Chemicals Age-related Disorders and their Origins in Environmental Exposures 17 Chemical Toxicity Prediction Category Formation and Read-Across 18 The Carcinogenicity of Metals Human Risk Through Occupational and Environmental Exposure... 

Jehazkova, N., Jaworska, J., Worth, A. P. (2010). Open source tools for read across and category formation In Cronin, M. T. D., Madden, J. (Eds.) 7w Silico Toxicology. Principles and Applications, Royal Society of Chemistry, Cambridge, pp. 408-445. 

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