The study of human colonic motility under physiological conditions has proved to be an elusive goal. We have used a two-stage pernasal technique to position sensors in the human colon for the prolonged monitoring of motility in freely ambulant subjects. Nine healthy volunteers were studied for a total recording time of 263 h, each study lasting between 13 and 48 (mean 29) h. Motor activity in all regions of the large bowel was characterized by scant and irregular contractions with infrequent bursts that did not conform to any pattern. No motor coordination was apparent between different regions of the large bowel. Contractile activity throughout the large bowel was reduced to a minimum during sleep and was enhanced on waking. Meals were an inconsistent stimulus to motor activity. The technique obviates the need for colonic preparation and allows complete freedom of the subjects throughout the study. In demonstrating the practical feasibility of this mode of studying the colon, these preliminary data highlight a requirement for the availability of appropriate equipment but raise questions about the design and use of such equipment and methods of data analysis.

In order to evaluate the diagnostic potential of liver ultrasonography (US), the charts of 23 cases with normal liver, 424 patients with chronic widespread, and 60 patients with focal hepatic diseases, who had undergone both US and liver biopsy, were reviewed. The positive predictive value of US was good in all hepatic disorders (range 86.9-96.5%), while its negative predictive value was very low (range 14.1-42.5%) in the various forms of widespread liver disease and suitable for screening purposes (74%) in focal lesions. Of the 507 cases, 39 with an ultrasonically suspected liver mass also underwent an echo-guided fine-needle aspiration, which showed a high sensitivity (85%) in the 27 biopsy-proved malignant lesions and excluded tumor cells in the remaining 12 cirrhotic cases. As regards US tissue diagnosis, hepatic tumors, fatty infiltration, and fibrosis were detected in 88%, 60%, and 49% of cases, respectively. Fat and fibrous content on biopsy were similarly and significantly correlated with both echo pattern and sound attenuation. Overall results suggest that in the group of widespread hepatic disorders the usefulness of US is greatly reduced by the fact that the patient's actual condition is not likely to be negative if US examination is normal and by the impossibility of differentiating fat from fibrosis. In focal lesions, the diagnostic value of US appears high and the method may frequently provide conclusive proof of the tumor if a positive cytodiagnosis on echo-guided aspirated material is done.

We performed esophageal investigations in 20 patients suffering from noncardiac chest pain in order to assess the diagnostic value of short- versus long-term manometric and pH studies. Patients had baseline esophageal manometry with two provocative tests: a Bernstein test and an intravenous injection of edrophonium. On a separate occasion they had a 24-hr ambulatory esophageal pH and motility recording. The Bernstein test provoked chest pain in two patients, while edrophonium injection did not elicit pain in any of the patients. The ambulatory pH study helped to establish the esophagus as the likely source of pain in one patient, and the ambulatory motility one in another. In our experience, ambulatory pH and motility recordings have a low diagnostic yield in the evaluation of patients with noncardiac chest pain.

The circadian pattern of intragastric acidity was assessed in 19 healthy subjects and 37 patients with active, endoscopically proven duodenal ulcer using 24-hr continuous intraluminal pH-metry. The median pH 24-hr profiles showed that ulcer patients had lower postprandial pH elevations and a smaller decline in acidity during the early morning hours when compared with controls. The after-lunch and -dinner area under the curve and maximum pH values were significantly higher in controls compared to ulcer patients. In the nighttime, the median pH values in controls were significantly higher during 9 PM to 12 PM (P = 0.02), 12 PM to 4 AM (P = 0.01), and 4 AM to 8 AM (P = 0.0008) compared to the ulcer patients. We conclude that the 24-hr acidity is higher in ulcer patients compared to healthy subjects and that the differences are particularly evident in the postprandial and nocturnal periods.

This study was undertaken to show whether the correlation between pH values indicated by an intraluminal pH electrode and those simultaneously recorded for gastric aspirates is not only linear but also proportional, so that the two measurement techniques can be considered alternative. A 24-h intragastric pH-monitoring with an antimony electrode, to which a nasogastric tube for hourly aspiration of gastric juice was closely attached, was performed on 20 duodenal ulcer patients. Our data show that the slope of the straight line related to 335 pH pairs is virtually equal to 1, whereas the elevation is almost equal to zero, and this result strongly suggests that a proportional relationship exists between intragastric and aspirate pH levels throughout the whole 24-h period. Besides, in the majority of cases (81%) the pH pairs differ by no more than 1 pH unit. It can be concluded that these two pH monitoring methods may be alternative.