FIELD U 

 Columns 65 and 66 



compound was candidate as indicated above, in which case Criterion 01 must be used in Field X, with 

 Fields U and Y coded with Symbol 1 in Columns 66 and 71, respectively. If the coder were to have 

 only the information that the survival time or duration of viability was increased, without an actual 

 time value to code in Field U, the field can not be coded and the evaluation must be by Criterion 01. 



However, if the test compound decreases survival time and the author does not specifically 

 indicate that it is due to the compound's toxicity, the only interpretation that should be given by the 

 CBCC coder is one of exacerbation of the situation causing death of the organism whose survival was 

 foreshortened under the conditions of the test. It should not be interpreted by the coder as toxicity 

 to the host; determination of toxicity and toxic dose levels should properly be made in organisms not 

 suffering a fatal condition. In such situations, therefore, Fields T- 1 and T-2 can only be coded with 

 the symbols for accelerating the pathology's action (Symbol 2 in Field T- 1 and Symbol 12 in Field T-2 

 or Symbol 7 in Field T-l and Symbol 1621 in Field T-2, according to whether or not the time value is 

 an increase in duration of viability or an increase in time of survival of pathology), Field U should be 

 coded with the decrease in survival time, and evaluation should be positive (inasmuch as the action 

 is coded in Field T as exacerbation) in Fields X and Y, using Criterion 12 or 57. As explained above, 

 if the author provides no actual time value nor data for calculating a decrease in survival time or 

 decrease in duration of viability, Field U can not be coded and the effect must be evaluated by 

 Criterion 01. 



Administration of the test compound can be continuous in testing for effects on survival time, 

 whereas, as explained in the previous division, a duration of action value can not be determined from 

 a test in which administration is continuous. 



Alteration of survival time as coded in Field U is illustrated graphically as follows; adminis- 

 tration of the test compound is not included in these diagrams. It may occur before or after infection 

 and it may be of limited duration or it may be continuous: 



Increase 



|Compound A:| 



|Infectlon| 



Time)- 



Survival time of 

 untreated controls 



Time coded in Field U; 

 increase In survival time 



No Effect 



Compound B:| 



llnfectionl 



Time)- 



Death of untreated controls AND 

 death of treated organisms 



Survival time of untreated 

 controls and of treated organisms 



(Field U is coded with Symbol 1 

 in Column 66, regardless of what 

 is coded in Column 65; 1. e. , no 

 increase in survival time. ) 



Fields T-l 

 and T-2 

 coded to 

 indicate a 

 therapeutic 

 effect. 



Decrease 



|Compound C:\ 



| Infection] 



Time)- 



Survival time of 

 untreated controls 



Fields T-l 

 and T-2 

 coded to 

 indicate 

 exacerbation 



Time coded in Field U; decrease 

 in survival time 



161 



