A computer model or "virtual stomach" revealed a central "road" in the human stomach, dubbed the Magenstrasse, that could explain why pharmaceuticals sometimes have a large variability in drug activation times, according to a team creating computer simulations of stomach contractions.
"We are predicting variables that we wish we could measure, but we cannot," says Dr. James G. Brasseur, professor of mechanical engineering, bioengineering and mathematics at Penn State. "Now that we know the Magenstrasse exists, we can look for it, but, it will not be easy to measure its existence and could require expensive technology."
Brasseur, working with Anupam Pal, research associate, Penn State and Bertil Abrahamsson, AstraZeneca, was interested in how the stomach empties its contents and how material passes from the stomach into the small intestines.
"The sphincter between the stomach and the small intestine is interactive," said Brasseur. "The sphincter opens and closes in a controlled way to regulate the flow of nutrient to the small intestines. Sensor cells in the intestines modulate the opening and closing."
Two types of muscle contractions control food movement in the stomach. One type of contraction, antral contractions, occur in the lower portion of the stomach and break down and mix stomach contents. The other type of contraction, fundic contractions, is over the upper surface of the stomach. It was thought that the fundic contractions move food from the top of the stomach where it enters from the esophagus, to the bottom of the stomach where the chyme leaves and enters the small intestine. The assumption was that particles left the stomach in the same order they entered the stomach.
The researchers modeled the stomach contents and discovered that a narrow path forms in the center of the stomach along which food exits the stomach more rapidly than the regions near the walls of the stomach. They used MRI data from human subjects to cre
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Contact: A'ndrea Elyse Messer
aem1@psu.edu
814-865-9481
Penn State
18-Sep-2006