John G. Moore

Gastric emptying of varying meal weight and composition in man. Evaluation by dual liquid- and solid-phase isotopic method.

Ten subjects were given self-selected filling meals (mean weight=1692 g) and meals of 900 and 300 g. The three meals varied in composition and total kcal. Solid and liquid phase gastric emptying was evaluated using99mTc-sulfur colloid-labeled chicken liver and [111In]DTPA, and emptying was quantitated using the geometric mean of the anterior and posterior counts. Emptying of the solid-phase marker was linear; mean half-emptying times were 277 min, 146 min, and 77 min for the filling, 900-g, and 300-g meals, respectively. Emptying of the liquid-phase marker was curvilinear, mean half-emptying times were 178 min, 81 min, and 40 min, for the filling, 900-g, and 300-g meals, respectively. Thus, meals of larger weight and kcal content were associated with longer emptying times for both solids and liquids.

Effect of age on gastric emptying of liquid-solid meals in man

A dual radioisotopic method was employed to study the rate of gastric emptying of meals in ten males with an average age of 31 years and 10 elderly males with an average age ot 76.4 years. All study subjects were fed a standardized 900-g meal labeled with a liquid (111indium-DTPA) and solid (99mtechnetium-tagged liver) phase isotopic marker. There were no significant differences in solid food emptying rates between the young and aged men. A delay in liquid emptying, however, was observed in the aged men. The clinical significance of this observation is unknown.

Influence of meal weight and caloric content on gastric emptying of meals in man.

This study was designed to assess the relative influence of meal weight and caloric content on gastric emptying of liquid and solid meals in man. A dual radioisotopic method which permits noninvasive and simultaneous measurement of liquid-and solid-phase emptying by external gamma camera techniques was employed. Nine healthy volunteer subjects ingested 50-,300-, and 900-g lettuce and water meals adjusted to either 68, 208, or 633 kcal with added salad oil. The following observations were made: (1) absolute emptying rates (grams of solid food emptied from the stomach per minute) increased directly and significantly with meal weight; (2) increasing meal total caloric content significantly slowed solid food gastric emptying but did not overcome the enhancing effect of meal weight; and (3) liquid emptying rates were uninfluenced by meal total kcal amount.

Circadian rhythm of gastric acid secretion in men with active duodenal ulcer

Twenty-one men with active duodenal ulcer underwent hourly gastric acid and 4-hourly plasma collections under fasting conditions. A statistically significant circadian rhythm was demonstrated for the group by population-mean cosinor analysis, a statistical technique designed for time-dependent measurements, for the 24-hr acid secretory output but not for plasma gastrin concentration. These findings are compatible with the interpretation that the circadian rhythm of unstimulated gastric acid secretion, here observed in most patients of the active ulcer group and previously reported for a group of healthy subjects, does not depend critically upon a circadian-rhythm change in plasma gastrin. Chronobiologic statistical techniques add an important quantitative element to the time-dependent measurement of gastrointestinal function of which one example is gastric acidity, with high rates occurring during the evening and low ones in early morning.

Variability of gastric emptying measurements in man employing standardized radiolabeled meals

Radiolabeled liquid and solid portions of standardized 300-g meals were administered on four different study days to eight healthy subjects in an attempt to define the range of inter- and intrasubject variability in gastric emptying. Meal half emptying times, analysis of variance, and intraclass correlations were computed and compared within and between subjects. The mean solid half emptying time was 58±17 min (range 29–92), while the mean liquid half emptying time was 24±8 min (range 12–37). A nested random effects analysis of variance showed moderate intrasubject variability for solid emptying and high intrasubject variability for liquid emptying. The variability of solid and liquid emptying was comparable and relatively large when compared with other reports in the literature. The isotopic method for measuring gastric emptying is a valuable tool for investigating problems in gastric pathophysiology, particularly when differences between groups of subjects are sought. However, meal emptying time is a variable phenomenon in healthy subjects with significant inter- and intraindividual day-to-day differences. These day-to-day variations in gastric emptying must be considered in interpreting individual study results.

Effect of body posture on radionuclide measurements of gastric emptying

The purpose of this investigation was to compare the effect of body posture on gastric emptying measurements of radiolabeled meals. Eight healthy male subjects were studied on four separate days. During each study subjects were fed a standardized meal of beef stew labeled with technetium-99m sulfur colloid, and orange juice. Measurements of solid-phase gastric emptying rates were obtained by a gamma camera. Subjects were studied in the lying, sitting, standing, or combined sitting-standing postures. The results demonstrated that the lying position significantly slowed gastric emptying compared to all other positions. Conversely, a decrease in emptying times of 51% and 35% occurred in the combined sitting-standing position compared to the lying and sitting position. These results support a marked effect of body posture on the radionuclide measurement of gastric emptying.

Day and Night Aspirin-Induced Gastric Mucosal Damage and Protection by Ranitidine in Man

The severity of gastric mucosal injury produced by aspirin (ASA) was endoscopically assessed during morning and evening studies in 10 healthy, male volunteers. In a randomized, double-blind design, subjects received either ASA (1300 mg) alone or ASA (1300 mg) plus Ranitidine (150 mg) or placebo tablets during morning and evening studies. Each subject had 3 morning and 3 evening studies. The severity of damage produced by ASA was assessed by counting the number of punctate mucosal hemorrhages observed in the gastric antrum and low-body. This study demonstrated (1) wide intersubject variability in the severity of damage produced by ASA (range of 47-1030 lesions/subject in morning studies), (2) significant protection against ASA-induced damage by Ranitidine and (3) significantly greater damage produced by ASA in the morning compared to the evening studies. Because evening acid secretory rates are higher and because ASA-induced damage is believed to be acid-dependent, this last observation was unexpected. It suggests mucosal resistance is higher in the evening and raises the possibility that there may be circadian variation in gastric mucosal resistance.

Exercise increases solid meal gastric emptying rates in men.

Gastric emptying rates of radiolabeled beef stew meals were measured in 10 healthy, young (median age=27 years) male subjects on each of three randomly chosen study days. The subjects either (1) stood at rest, (2) walked on an exercise treadmill at 3.2 km/hr, or (3) at 6.4 km/hr during the study while gastric emptying was being monitored by externally positioned gamma cameras. Compared to the standing at rest study, exercise significantly increased gastric emptying (at rest emptying half-time (t1/2)=72.6±7.6 (sem) min; 3.2 km/hr t1/2=44.5±3.9 min, P=0.0051; 6.4 km/hr t1/2=32.9±1.9 min, P=0,0051). The 6.4 km/hr emptying time was significantly (P=0.0249) faster than the 3.2 km/hr emptying time. Thus, the amount of exercise is a physiological factor that alters solid meal gastric emptying rates.

The Relation of Plasma Gastrin to the Circadian Rhythm of Gastric Acid Secretion in Man

24-hour basal gastric acid collections were obtained from 10 healthy, young (ages 22–27) male volunteers. The hourly secretory pattern, which described a circadian periodicity (low morning, high eveni

Effect of wine on gastric emptying in humans.

The effect of wine on gastric emptying of meals was studied in 10 healthy male subjects. A dual radioisotopic method was employed utilizing isotope tracers added to the liquid (111In-diethyltriamine pentaacetic acid) and solid phases (99mT-tagged chicken liver) of the meal. In a random design subjects were fed two standardized 900-g meals containing 450 g of solid food ingredients and 450 g of either Cabernet Sauvignon (mean ethanol concentration = 9500 mg/dl) or low-alcohol Cabernet Sauvignon (mean ethanol concentration = 1312 mg/dl). In addition, 7 of the 10 subjects were fed wine and low-alcohol wine without solid food. Wine, when compared with low-alcohol wine, did not significantly alter gastric emptying of either liquid or solid food components.