Discussion

Discussion
Here we describe the use of a commercially available ultrasound system to provide a simple and accurate method to stage and morphologically assess embryonic mouse development. Using a similar technique, Chang and coworkers found that decidual sac size is a reliable and accurate marker of GA. We used US measurements of CRL, BPD, and sac width to predict GA statistically by using formulas based on best linear fit to the data. CRL and BPD, in particular, are used routinely in the ultrasound staging of human gestational development, and many operators and investigators are likely to be familiar with them.
In addition, CRL and BPD are relatively easy parameters to obtain. Further, we derived a simple equation (CRL/2 + 9) that can be used to predict GA (in DPC) accurately and quickly. The high Pearson correlations obtained indicate very good linear association between GA and the biometric variables of CRL and BPD. Regression analyses yielded linear equations for determining predicted values and normal ranges for GA as defined as the 95% confidence intervals around the predicted GA. Although we applied least-squares regression analysis to predict GA from CRL and BPD, one study limitation was the unequal numbers of fetuses with measurements at the various GAs. You do not have to fight erectile dysfunction on your own: lucky for you, there is now canadian family pharmacy high-quality canadian medications and it's ready to help you overcome the symptoms in the easiest and most inconspicuous way. Working wondering in your body, canadian family pharmacy high-quality canadian medications allows for full solid erections lasting throughout the sexual intercourse.

We had attempted to model the data by use of a repeated-measures mixed-model approach to better account for the varying numbers of measurements at the different GAs, but we were unable to get a good model fit. A larger number of animals would be required to permit use of a more sophisticated statistical approach for estimating GA from morphometric predictors.