FIELDS W, X, and Y 



Columns 68; 69 and 



70; and 71 



When the chemical fails to produce the response, Fields X and Y can code only the failure of whatever 

 amount of chemical was administered. Many tests are performed with quantities of a test compound 

 below the maximum dose that could be administered, for any of several reasons, but frequently because 

 the compound is available only in small quantities. The only significance such negative test results 

 can claim to have is that, at the dose tested , the response in Field T was not produced. This is never 

 synonymous with having demonstrated that the test compound in adequate quantities (up to a maximum 

 tolerated dose) was inactive in producing the response in Field T. 



It will be understood that in interpreting any biology code line, the evaluation is interpreted in 

 the light of all other aspects of the test, including the dose coded in Fields M, N, and P. However, 

 Fields M, N, and P can not reveal what relation that coded dose has to the maximum dose that might 

 have been given- -in other words, those fields can not indicate whether it is or not the maximum dose 

 possible or the minimum dose necessary. 



For example, there are numerous data from tests for non-toxic responses in which the chemical 

 is administered at or near the maximum dose tolerated by the biological system, toxicity and MTD- 

 determining tests having been run prior to the test being coded . The failure to produce the non-toxic 

 response coded in Field T, when administered at maximum tolerated level, is of much more significance 

 than the failure to produce the response at a lower dose; in essence, the former data imply that, under 

 the conditions of a given test, the test compound CAN not produce a given response in a given organism, 

 whereas the latter data can only state that it DID not produce the response. This distinction is impor- 

 tant because of the CBCC's ultimate objective which involves study of the comparative ability of com- 

 pounds to cause biological response, regardless of the size of the dose necessary to produce the bio- 

 logical response, as well as the relative efficiency (potency) of those compounds demonstrated to cause 

 the biological response, in terms of the dose size needed for that response. To accommodate such dis- 

 tinctions, a coding provision has been made for qualifying the evaluation coding of Fields X and Y; in 

 the case of negative data, for example, Fields X and Y are equipped only to code the fact that a chemical 

 DID not produce a given response, whereas they have no way of indicating whether the test has 

 demonstrated that the compound CAN not produce the response. 



The provision for coding the information supplementary to Fields X and Y is made by Field W 

 where eight letter symbols have been assigned definitions for the distinctions Fields X and Y are 

 incapable of making, such as the distinction described in the preceding paragraph. This provision was 

 made recently, replacing an earlier use of Field W. (The former use of Field W is described at the end 

 of this section. ) Therefore, very little coding of Field W has been done using the symbols as supple- 

 ment to the coding of Fields X and Y. Coding of these aspects of test results has not been tried over a 

 sufficiently long period to determine all the associated difficulties nor to assay its ultimate usefulness 

 in sorting, assembling, and interpreting evaluation information for correlation studies. The concepts 

 and definitions of symbols are nevertheless included here in a form expanded from that which has been 

 used by the CBCC. (The use of the symbols is indicated also with the discussion of each criterion of 

 Field X in the section on Specific Directions and Explanations. ) This information coded in Field W is 

 largely dependent on results of tests supplementary to the test being coded, such as those prior tests 

 which have determined that the dose administered is or is not a maximum tolerated dose or whether the 

 dose is the minimum effective dose or the response is the maximum of which the test compound is 

 capable. 



Of the eight symbols of Field W, Symbol K permits the designation by code that the test has 

 demonstrated the chemical's failure to produce the response at the dose level known by prior testing to 

 be the maximum that can be administered; this symbol therefore indicates that the chemical CAN NOT 

 produce the response. Symbol J is used in Field W for all other negative test results; in other words, 

 it is used when the dose failing to produce a given response is not definitely known to be the maximum 

 dose that might be administered. 



In studying chemicals on the basis of their abilities to affect biological systems, especially 

 with the CBCC's purpose of gaining suggestion about other chemicals to test with a given biological 

 system or suggestion about other biological systems to combine with a given chemical, a code provi- 

 sion is important which can distinguish those chemicals which are demonstrated to be so nearly 

 absolutely inactive that they can be removed from consideration. (This particular provision for dis- 

 tinction was not made in Field Y, largely because symbols for that field had been exhausted, having 

 used all numerical symbols and both the 11 and 12 IBM zone punches. ) 



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