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Purpose\ud This work demonstrates specifically tailored microbubble‐based preparations and their suitability as MRI contrast agents for ingestion and measuring temporal and spatial pressure variation in the human stomach.\ud \ud Methods\ud Enhanced alginate spheres were prepared by incorporating gas‐filled microbubbles into sodium alginate solution followed by the polymerization of the mixture in an aqueous calcium lactate solution. The microbubbles were prepared with a phospholipid shell and perfluorocarbon gas filling, using a mechanical cavitational agitation regime. The NMR signal changes to externally applied pressure and coming from the enhanced alginate spheres were acquired and compared with that of alginate spheres without microbubbles. In vivo investigations were also carried out on healthy volunteers to measure the pressure variation in the stomach.\ud \ud Results\ud The MR signal changes in the contrast agent exhibits a linear sensitivity of approximately 40% per bar, as opposed to no measurable signal change seen in the control gas‐free spheres. This novel contrast agent also demonstrates an excellent stability in simulated gastric conditions, including at body temperature. In vivo studies showed that the signal change exhibited in the meal within the antrum region is between 5% and 10%, but appears to come from both pressure changes and partial volume artifacts.\ud \ud Conclusion\ud This study demonstrates that alginate spheres with microbubbles can be used as an MRI contrast agent to measure pressure changes. The peristaltic movement within the stomach is seen to substantially alter the overall signal intensity of the contrast agent meal. Future work must focus on improving the contrast agent's sensitivity to pressure changes.

In this paper, technical development results of "sensitive endoscope hood" for an endoscopic surgery operative procedure, NOTES (Natural Orifice Translumenal Endoscopic Surgery) with a flexible endoscope is reported. A microsensor integrating an absolute pressure sensor and a temperature sensor is embedded inside of the thin wall of a disposable endoscope hood. Intraluminal pressure and temperature of stomach can be measured under the NOTES operation using the sensor hood, and it is very helpful to keep the inside condition of stomach for the operating doctor. Especially, monitoring of stomach pressure have two important purposes. The first importance is quantitative measurement of tumor sizes under a constant intraluminal pressure of stomach for treatment selection. The second importance is prevention of putting the patient in danger caused by over transmission of air. Monitoring with embedded sensor in flexible endoscopic surgery have not been tried and reported in NOTES field with single flexible endoscopy. This is the exploratory work in the area of flexible microscopic surgery, and is a new technology field and challenge of well-established MEMS sensors. The developed endoscopy hood was tested in an animal experimentation with Beagle dog, and its performance and robustness have been successfully demonstrated.

When we consider the medical economy, the Obesity is one of the leading preventable causes of death worldwide. However, a lot of previous scientific papers reported that 95% of obesity patients would not be able to control their weight by the diet. The surgical operation has been considered to the subjects with severe obesity. But, there is a possibility of complication or comorbidity in surgical operation. Tohoku University started to develop the expanding capsule with transcutaneous energy transmission system (TETS) having the same effect as the surgical operation. The capsule in the stomach will expand mechanically by energy transmission from outsides of the body, when the obesity patients will felt hungry. Small linear drive with folding umbrella type actuator would enable us the expansion of the diet capsules. Satisfactory characteristic of the energy transmission was obtained by the trial model of TETS during animal experiments. Animal experiments with healthy adult goats enabled us the evaluation of the inner stomach pressure time series changes, and feasibility study. Double blind test of the expanding capsule is now under planning. If the expanding capsule diet control system will be embodied, it becomes the gospel of the obese subject.

We used micro computed tomography to produce a high-resolution density image of the lobster (Panulirus interruptus) stomach and identified on this image the previously defined stomach ossicles. These data are the first coordinate-based, three-dimensional description of the stomach and are a necessary first step for developing biomechanical models of it. They are also interesting for several reasons in their own right. First, the ossicles showed large shape and density variations. These data suggest that different ossicles may serve dif- ferent functions, with some acting as force-delivering levers, some as spring-like elements, and some as wall- like elements that resist internal stomach pressure or function as two-dimensional force-delivering plates. Sec- ond, large intra-ossicle density variations were present in individual ossicles, reminiscent of I-beams, oval bicycle frames, and similar mass-minimizing structural elements, suggesting that evolution has minimized ossi- cle mass and identifying which ossicle regions are most likely important in force delivery. Third, joints appeared to be either continuous density interconnections without distinct separations between the ossicles or 'floating' joints in which the ends of the two ossicles were sepa- rated by relatively large distances spanned by connec- tive tissue. In these latter joints, although the distance between ossicle ends is likely maintained at a relatively constant value, a wide range of ossicle angles would thus be theoretically possible. Notably absent are close- apposition, morphologically specialized joints such as hinge or ball-and-socket joints. J. Morphol. 270:1029

1. The present investigation was conducted to test the hypothesis that the respiratory system is stressed more during exhaustive exercise in chronic hypoxia than in normoxia. 2. Four healthy male subjects (aged 33-35 years) exercised on a cycle ergometer at 75% of the local maximum oxygen consumption (Vo2,max) until exhaustion, at sea level (SL) and after a 1 month stay at 5050 m (HA). 3. Airflow at the mouth (V), oesophageal (Po) and gastric (Pg) pressures were measured at rest, during exercise and recovery. Minute ventilation (VE), respiratory power (Wresp), respiratory frequency (f) and transdiaphragmatic pressure (Pdi) were calculated from the measured variables. 4. The subjects' mechanical power output of cycling at HA was 23.7% lower than at SL. In spite of this reduction, time to exhaustion at HA was 55.3% less than at SL. VE increased slightly during exercise at SL, but showed a marked increase at HA, and at the end of exercise at HA was 47.3% higher than at SL. 5. Respiratory power increased more at HA than at SL (77.3% higher at the end of exercise) due to the increase in f needed to sustain the high VE. 6. Gastric pressure swings were negative at the end of HA exercise but always positive at SL. The Pai:Po ratio reached values below 1 at HA but never at SL. 7. These data seem to indicate that the respiratory system is stressed more during submaximal exercise at HA than at SL. We suggest that the exceedingly high VE demand, requiring an excessive Wresp, may lead to fatigue of the diaphragm.

A telemetering system for veterinary research dealing with stomach pressure of ruminant animals is described. The system, consisting of a transmitter, receiver, and recorder, has worked satisfactorily with an animal in a 4-aere enclosure, and greater ranges are anticipated.