SEND Example.In vitro Bacterial Reverse Mutation Assay

This is an example showing the report table, trial design, and results from the in vitro bacterial reverse mutation test of an example study, Study #8325064. This bacterial reverse mutation test uses four different amino acid-requiring strains of Salmonella typhimurium (S. typhimurium) and one strain of Escherichia coli (E. coli) to detect point mutations, which involve substitution, addition or deletion of one or a few DNA base pairs. 

In this example, the Trial Summary dataset, ts.xpt, includes many informational fields that may provide context at the study level, for Study 8325064.  Also, TSGRPID has been used to link records (name, location, country) related to the test facility (TSGRPID = 1) and records related to the Test Site (TSGRPID = 2). The Study Director is associated with the Test Facility and the Principal Investigator is associated with the Test Site. Finally, the Primary Treatment CAS Registry Number is not known and this is recorded as an empty TSVAL and UNKNOWN in the corresponding TSVALNF.

This example trial set dataset, tx.xpt, shows information about the test conditions for SetA and SetR in this example study. For brevity, this does not show information for SetF, SetG, or any other sets.  A fully formed tx.xpt for this example study would include information about the test conditions for all sets. 

REFID values are defined by the applicant to uniquely identify the observational unit within an experimental unit.  In the simplified picture of an assay (below), the test tube that contains the possible mutagen is an example of an entity that would have a REFID indicating information at the level of trial set. The petri plate created from that test tube and used to count revertant numbers is an example of an entity that would be at an observational level. 

This picture does not depict the more complicated procedures, trial sets, or observational units for our example study, 8325064.   For study 8325064, the applicant chose to define the REFIDs at the trial set level with a single character (e.g., A, F, G, R) and chose to define REFIDs at the observational level based on the location of each tube in one of multiple exposure/incubation plates (e.g, 6_1 for plate 6, position 1).