Presentation Summary

On October 17, 2025, Dr. Stefan Rose will challenge retrograde extrapolation's scientific validity by focusing on an impossible requirement: knowing when and how much the pyloric valve opens to allow gastric contents to flow into the small intestine where the majority of alcohol absorption occurs—information unavailable without continuous physiological monitoring of multiple timed blood or breath samples starting at the beginning of the drinking episode.

The presentation will cover the complex factors controlling pyloric valve opening and closing: neural regulation (vagus nerve, myenteric plexus, splanchnic nerve), hormonal influences (gastrin, insulin, secretin, somatostatin, motilin, and other peptides), and external variables that delay gastric emptying and invalidate any retrograde extrapolation, including food, medications, trauma, surgery, and disease states like diabetes.

Dr. Rose argues that because pyloric valve status at any point in time of a drinking episode cannot be determined retroactively, retrograde extrapolation is fundamentally flawed and dubious, and addresses why analytical chemistry training has overshadowed comprehensive pharmacological education in the field.

About the Presenter

Dr. Stefan Rose is a physician with over 40 years of experience spanning Forensic Toxicology, Clinical Pathology, and General Psychiatry. He completed formal Forensic Toxicology training at the Dade County Medical Examiner Department (1989-1991), founded the first DUI laboratory at the University of Miami (1992), and completed psychiatric residency (1995-1998), where he correlated behavioral effects of drugs and ethanol with laboratory findings. He has served as a courtesy professor in Chemistry at FIU since 1997, is Board Certified by the National Board of Medical Examiners, and has extensive expert testimony experience in state, federal, civil, and criminal courts.

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