FIELDS G-l and G-2 

 Columns 27 and 28 



of experimental physiological stress should be coded by Symbol N, 0, or 7, not by Symbol 

 2, P, Q, or R. (E. g. , application of a hormone excess to cause a stress which is itself 

 not the condition being treated would be coded by Symbol N, 0, or 7 and not by Symbol 2 

 or C; a surgical excision of an organ or one of a pair of organs to produce a stress which is 

 not the condition being treated would be coded by Symbol N, 0, or 7, not by Symbol P. ) 

 For example, if one kidney is removed to produce experimental stress on the remaining 

 kidney, "kidney" is coded in Field H- 1 (with Symbol N in Field G) as the organ under stress 

 (if the kidney is also the organ responding to the test compound) or in Field H-2 (with 

 Symbol in Field G) as the organ under stress (if the kidney is not the organ specifically 

 responding to the test compound or if the general organism response rather than a specific 

 organ's response is being coded). 



1 1. Use of Symbols 6 and J; STATES OF resistance to, or sensitivity to, the test compound vs . 

 PRODUCTION OF THOSE STATES 



A. STATES of the test organism 



(1) Sensitivity (Symbol 6 ) 



(Biological "sensitivity" to a chemical is the responsiveness of an organism to a 

 chemical; i. e. , any "action" of a test compound can be also described as due to a 

 responsiveness or sensitivity of the test organism. A " produced sensitivity" or 

 "increased sensitivity" [including "sensitization"] is a phenomenon which is not 

 evinced on an initial exposure but is brought about by some biochemical adjustment 

 during the first exposure. ) 



When a test organism develops a sensitivity to a test compound on exposure to that 

 compound, the sensitivity is not revealed except by an application subsequent to that 

 initial application. (This is self-evident, by definition, since if the sensitivity had 

 been present at the initial exposure, it would not have been a "developed sensitivity", 

 but merely a test organism "response". ) The CBCC codes the production of sensitivity 

 in Field T as an action of that first exposure (Field T-2 symbols of the 51-- series and 

 Symbol 58), even though evidence is from subsequent administrations. The actual 

 sensitive response can not be coded in the code line which codes the first exposure to 

 the test compound, since the response did not appear except on subsequent exposures. 

 This is discussed also in Division 11 of the Specific Directions and Explanations for 

 Fields M and N, and in Division 20 of the Specific Directions and Explanations for 

 Field T-2. 



However, if a code line is constructed in which are actually coded in Field T the 

 responses caused by or affected by the induced hypersensitivity, it is essential that 

 Field G be coded with Symbol 6 to indicate that the response or degree of response was 

 due to a previous exposure to the test compound (or to a secondary compound which 

 caused a cross- sensitivity to the test compound). 



(2) Resistance (Symbol J ) 



When a test organism has been made refractory to the action of a test compound, prior 

 to treatment with that compound in the test being coded, that response to the test 

 compound will consequently be less than in an organism not having been so pretreated. 

 Therefore, it is important that Field G be coded with Symbol J to indicate that the 

 response and degree of response should be interpreted in the light of the results of that 

 previous exposure to the test compound which has stimulated a resistance in the test 

 organism (or a previous exposure to a secondary compound, or to an infectious organism 

 that elaborated that secondary compound, which has caused a cross-resistance to the 

 the test compound). 



B. PRODUCTION OF the states of resistance and sensitivity 



The production of resistance or sensitivity to a test compound is only revealed by exposures 



55 - 



