Some Questions of Validity of Results of Experiments in Applied Teratology. 2. Statistical Analysis of Experimental Data in Case of Single Fetuses with External Anomalies

Abstract

Assessment of the embryotoxic properties of ftorosan, a blood substitute with an oxygen-transporting function, in experiments with rats revealed three fetuses with phocomelia, micrognathia, and eventration of the frontal abdominal wall in 2 of 22 litters from a group of 23 pregnant females given doses of 25 ml/kg of body weight on days 6-16 of pregnancy. In two repeated experiments (24 litters examined in each experiment), one fetus with similar anomalies was detected in each experiment. These data, along with similar hypothetical versions of the results, were analyzed by means of an independent criteria test and Wald's sequential probability ratio test with a view towards evaluating the feasibility of the use of these two tests to analyze these kinds of data. Evaluation was carried out by comparing decisions made on the basis of the researcher's intuition to the results of statistical analysis. Application of these tests under the conditions of comparing the experimental data to the “historical” data, rather than to the concurrent control data, was shown to insure correct decision-making on the basis of experimental results, along with determining the volume of studies needed to be conducted.

Key Words: :

• Ftorosan
• Embryotoxicity
• Rats
• Fetuses
• Statistical analysis