A comparison of the gastric and central nervous system effects of two substituted benzamides in normal volunteers

The iso-osmo-resistivity theory of digestion

This novel, iso-osmo-resistive theory offers electro-resistivity of food components as a new dimension for digestion. Firstly, fats, carbohydrates and proteins differ markedly in their resistivity, which offers a way to monitor them, especially when digestive enzymes cause consistent and distinctive changes. Secondly the state of iso-resistivity is in theory most likely to pass through the membranes of absorbing cells and be compatible with plasma in portal blood vessels. Hence, the theory proposes that the aim of the digestive process in the upper gut is to present digesta to absorption sites in a state at, or close to, iso-osmo-resistivity. It requires a method of monitoring resistivity which could be achieved by neuronal endings based in the upper gut mucosa. They could be simple nerve endings or, probably less likely, part of the structure of duodenal Brunner's Glands. They would monitor the overall effect of the various digestive processes initiated by the G-protein-coupled receptors (GPCRs). The combination of sensitive electroreceptor and osmoreceptor output would provide a system that would accurately monitor the overall progress of digestion to conserve enzyme production.

Double-blind, randomized, placebo-controlled study to evaluate the effects of tegaserod on gastric motor, sensory and myoelectric function in healthy volunteers

BACKGROUND

The effects of tegaserod on gastric accommodation and postprandial satiety remain unclear.

AIM

To compare the effects of tegaserod 6 mg twice daily vs. placebo on gastric volumes, postprandial symptoms, gastric emptying, small bowel transit and the surface electrogastrogram in female and male healthy volunteers.

METHODS

Randomized, double-blind, placebo-controlled study evaluated gastric function before and after 7 days of tegaserod 6 mg twice daily (n = 21) vs. placebo (n = 20) in healthy volunteers. Validated methods were used to study gastric emptying, myoelectrical activity, volumes and satiation postnutrient challenge.

RESULTS

There were no significant effects of tegaserod on the primary endpoints assessing gastric function: emptying of solids or liquids, total gastric volumes or myoelectrical activity. Maximum tolerated volume and aggregate symptom score with nutrient challenge on placebo were 1,035 mL (+/-44) and 130 (+/-15) vs. 989 mL (+/-43) and 117 (+/-15) during tegaserod, respectively (all P = N.S.). Postprandial change in proximal gastric volume by single photon emission-computed tomography was decreased in females on tegaserod (246 +/- 30) vs. placebo (358 +/- 32) (P = 0.015). Proximal fasting volumes in females were increased on tegaserod (126 +/- 12) vs. placebo (92 +/- 13) (P = 0.066).

CONCLUSIONS

While tegaserod decreased proximal gastric volume change after a meal, it does not appear to have significant effects on gastric motor and sensory function in healthy individuals. Further studies are required in patients with disturbances of gastric motor and sensory function.

Optimal placement of impedance epigastrography electrodes

Impedance electrogastrography (IE) is a noninvasive method to assess gastric contractile activity. This indirect method uses a four-terminal impedance measuring method to determine impedance variations of the gastric region of the torso. These variations can be related to changes in the stomach shape and, therefore, to gastric contractions. Because the impedance variations are very small, the placement of the measuring electrodes on the skin is critical. In this study, a three-dimensional resistor model consisting of 4,466 resistors was used to simulate the human torso. The model was implemented on a personal computer, and the experimentally obtained optimal electrode locations were found to be superior to the commonly used ones. Measurements of volunteers confirmed these findings.