13C-octanoic Acid Breath Test Research Articles

Tissue ghrelin level and gastric emptying rate in adult patients with celiac disease

Celiac disease (CD) patients show a number of gastrointestinal motor abnormalities. Ghrelin, a gastric peptide implicated in short-term feeding control and long-term body weight regulation, has been recently considered a key regulator of gastric motility. The aim of this study was to evaluate the gastric emptying rate of solids and the density of ghrelin-immunopositive cells in adult CD patients before and at least 1 year after starting a gluten-free diet. Twenty CD patients (M 8/F 12; mean age 36 years) and 10 controls underwent endoscopy with gastric and duodenal biopsies and 13C-octanoic acid breath test to measure gastric emptying of solids. Celiac disease patients repeated the protocol at least 1 year after starting gluten-free diet. Ghrelin tissue levels were evaluated by immunohistochemistry on gastric mucosa specimens. Gastric emptying time was normal in all control subjects (t(1/2) = 89 +/- 16 min) while it was delayed in CD patients prior to gluten-free diet (t(1/2) = 252 +/- 101 min; P < 0.005). The mean number of ghrelin-positive cells/field (x 400) was 14.4 +/- 2.7 in controls and 25.3 +/- 5.7 in CD patients respectively (P < 0.0001). Gluten withdrawal was effective in normalizing gastric emptying time in all CD patients (97 +/- 14 min; P < 0.0001) and resulted in a significant reduction of the density of ghrelin-immunopositive cells (19.8 +/- 5.4; P < 0.0001). The density of ghrelin-positive cells correlated directly with the degree of duodenal damage (P < 0.001) and inversely with the body mass index of CD patients (P < 0.0001). However, in neither CD patients nor controls, a correlation between tissue ghrelin levels and gastric emptying rate was detected. In conclusion, tissue ghrelin level does not correlate with gastric emptying rate in adult CD patients and in controls.

Effect of peripheral obestatin on food intake and gastric emptying in ghrelin‐knockout mice

The finding that obestatin, a peptide encoded by the ghrelin gene, opposes ghrelin's stimulatory effect on food intake and gastric emptying has been questioned. The effect of obestatin has been mostly investigated in fasted rodents, a condition associated with high blood levels of ghrelin which may mask the effect of obestatin. We therefore investigated the effect of obestatin on food intake, gastric emptying and gastric contractility in ghrelin knockout mice. The effect of obestatin on 6-h cumulative food intake was studied in fasted wildtype (ghrelin+/+) and ghrelin knockout (ghrelin-/-) mice. In both genotypes, the effect of obestatin and/or ghrelin was studied in vivo on gastric emptying measured with the (14)C-octanoic acid breath test and in vitro on neural responses elicited by electrical field stimulation (EFS) of fundic smooth muscle strips. Administration of obestatin did not influence fasting-induced hyperphagia or gastric emptying in both genotypes. Injection of ghrelin accelerated gastric emptying in ghrelin+/+ and ghrelin-/- mice but the effect was not reversed by co-injection with obestatin. In fundic strips from ghrelin+/+ and ghrelin-/- mice, ghrelin increased EFS-induced contractions, but obestatin was without effect. However, co-administration with obestatin tended to reduce the excitatory effect of ghrelin in both genotypes. In ghrelin-/- mice, obestatin failed to affect food intake and gastric motility. These results suggest that endogenous ghrelin does not mask the effect of obestatin and confirm that obestatin administered peripherally is not a major regulator of satiety signalling or gut motility.

Gastric emptying rate in subjects with experimentally shortened dental arches: a pilot study

Although a shortened dental arch has been reported to provide sufficient subjective chewing ability, the loss of molar occlusion significantly reduces trituration ability, and may result in an impaired digestive function including delayed gastric emptying. This study investigated the effect of the experimental loss of molar occlusion on gastric emptying rate. Thirteen healthy dentate males underwent two sessions of gastric emptying rate measurement after ingestion of the same test meal that contained ham, bread and an egg mixed with carbon-labelled octanoic acid. A test food was divided into nine equal portions, and each was consumed in 60 cycles of chewing. In one of the two sessions, the subjects wore an intraoral appliance devised to simulate the occlusal conditions of the shortened dental arches. Two parameters of gastric emptying; namely, the lag phase (T(lag)) and gastric half-emptying time (T(1/2)), were evaluated by means of a (13)C-octanoic acid breath test. Following the measurement of gastric emptying in each session, masticatory performance was evaluated by a conventional sieve test. Masticatory performance decreased significantly in case of loss of molar occlusion (78.1 +/- 11.1% versus 33.4 +/- 18.2%, P <0.001); however, no significant changes were observed in terms of the gastric emptying parameters (T(lag): 99 +/- 19 versus 105 +/- 34 min; T(1/2): 168 +/- 32 versus 178 +/- 48 min). Within the limitations of this study, it was concluded that reduction in food trituration caused by shortening of the dental arch does not significantly affect gastrointestinal digestive function.

Exercise and postprandial lipaemia: effects on peripheral vascular function, oxidative stress and gastrointestinal transit

Postprandial lipaemia may lead to an increase in oxidative stress, inducing endothelial dysfunction. Exercise can slow gastric emptying rates, moderating postprandial lipaemia. The purpose of this study was to determine if moderate exercise, prior to fat ingestion, influences gastrointestinal transit, lipaemia, oxidative stress and arterial wall function. Eight apparently healthy males (age 23.6 ± 2.8 yrs; height 181.4 ± 8.1 cm; weight 83.4 ± 16.2 kg; all data mean ± SD) participated in the randomised, crossover design, where (i) subjects ingested a high-fat meal alone (control), and (ii) ingested a high-fat meal, preceded by 1 h of moderate exercise. Pulse Wave Velocity (PWV) was examined at baseline, post-exercise, and in the postprandial period. Gastric emptying was measured using the 13C-octanoic acid breath test. Measures of venous blood were obtained prior to and following exercise and at 2, 4 and 6 hours post-ingestion. PWV increased (6.5 ± 1.9 m/sec) at 2 (8.9 ± 1.7 m/sec) and 4 hrs (9.0 ± 1.6 m/sec) post-ingestion in the control group (time × group interaction, P < 0.05). PWV was increased at 2 hrs post-ingestion in the control compared to the exercise trial; 8.9 ± 1.7 vs. 6.2 ± 1.5 m/sec (time × group interaction, P < 0.05). Lipid hydroperoxides increased over time (pooled exercise and control data, P < 0.05). Serum triacylglycerols were elevated postprandially (pooled exercise and control data, P < 0.05). There were no changes in gastric emptying, cholesterol, or C-reactive protein levels. These data suggest that acute exercise prior to the consumption of a high-fat meal has the potential to reduce vascular impairments.

Gastric emptying in diabetic patients by the 13C-octanoic acid breath test: role of insulin in gastric motility

Gastric emptying in diabetic patients by the 13C-octanoic acid breath test: role of insulin in gastric motility

Gastric Emptying of Solids and Semi-solids in Morbidly Obese and Non-obese Subjects: An Assessment Using the 13C-Octanoic Acid and 13C-Acetic Acid Breath Tests

It has been suggested that obesity is associated with an altered rate of gastric emptying. The objective of the present study was to determine whether the rates of solid and semi-solid gastric emptying differ between morbidly obese patients and lean subjects. The Gastric-emptying time (GET) of solid and semi-solid meals were compared between lean healthy subjects and morbidly obese patients enrolled in two previously published studies. GET of solid and semi-solid meals was measured using the 13C-octanoic acid breath test and 13C-acetic acid breath test, respectively, in 24 lean and 14 morbidly obese individuals of both sexes. Student t-test was used to compare the mean data between the lean and morbidly obese groups. The influence of sex, gender, BMI and morbid obesity on the GET of solid meals was verified by linear regression analysis. Mean t(1/2) values of solid GET (+/- standard deviation) were 203.6 +/- 76.0 min and 143.5 +/- 19.1 min for lean and obese subjects, respectively (P = 0.0010). Mean t(lag) values of solid GET were 127.3 +/- 42.7 min and 98.4 +/- 13.0 min for lean and obese subjects, respectively (P = -0.0044). No significant difference in semi-solid GET was observed between the lean and morbidly obese groups. The present study demonstrated a significantly enhanced gastric emptying of the solid meal test in morbidly obese patients when compared to lean subjects. This finding is compatible with the hypothesis that rapid gastric emptying in morbidly obese subjects increases caloric intake due to a more rapid loss of satiety.

The impact of admission diagnosis on gastric emptying in critically ill patients

IntroductionDisturbed gastric emptying (GE) occurs commonly in critically ill patients. Admission diagnoses are believed to influence the incidence of delayed GE and subsequent feed intolerance. Although patients with burns and head injury are considered to be at greater risk, the true incidence has not been determined by examination of patient groups of sufficient number. This study aimed to evaluate the impact of admission diagnosis on GE in critically ill patients.MethodsA retrospective review of patient demographics, diagnosis, intensive care unit (ICU) admission details, GE, and enteral feeding was performed on an unselected cohort of 132 mechanically ventilated patients (94 males, 38 females; age 54 ± 1.2 years; admission Acute Physiology and Chronic Health Evaluation II [APACHE II] score of 22 ± 1) who had undergone GE assessment by 13C-octanoic acid breath test. Delayed GE was defined as GE coefficient (GEC) of less than 3.20 and/or gastric half-emptying time (t50) of more than 140 minutes.ResultsOverall, 60% of the patients had delayed GE and a mean GEC of 2.9 ± 0.1 and t50 of 163 ± 7 minutes. On univariate analysis, GE correlated significantly with older age, higher admission APACHE II scores, longer length of stay in ICU prior to GE measurement, higher respiratory rate, higher FiO2 (fraction of inspired oxygen), and higher serum creatinine. After these factors were controlled for, there was a modest relationship between admission diagnosis and GE (r = 0.48; P = 0.02). The highest occurrence of delayed GE was observed in patients with head injuries, burns, multi-system trauma, and sepsis. Delayed GE was least common in patients with myocardial injury and non-gastrointestinal post-operative respiratory failure. Patients with delayed GE received fewer feeds and stayed longer in ICU and hospital compared to those with normal GE.ConclusionAdmission diagnosis has a modest impact on GE in critically ill patients, even after controlling for factors such as age, illness severity, and medication, which are known to influence this function.

Stepped assessment of gastric emptying of a solid meal using the 13C-octanoic acid breath test

The (13)C-octanoic acid breath test is widely used for evaluating gastric emptying of solids. Since the results of this test are influenced by multiple factors such as the time required to grind the solid meal into smaller particles, the gastroduodenal transport time of the ground meal, and the time required for bowel drug absorption and drug dispersion, the administration of a test meal by the oral route alone cannot result in an accurate measurement of the complicated process of emptying the stomach of solids. The aim of the present study was to evaluate each phase of gastric emptying of solids by varying the administration route of the test meal. Six healthy male volunteers (mean age: 33.2 yr) participated in the study. The test meal consisted of a bowl of rice topped with a mixture of boiled chicken and eggs admixed with 100 mg of (13)C-octanoic acid (total: 273 kcal). All subjects were given the test meal by each of the following three methods: 1. Normal oral intake of the test meal, 2. Feeding of the ground test meal through a nasogastric tube, 3. Feeding of the ground test meal through a duodenal tube. For each set of examinations, the mean residence time (MRT), half-emptying time (T(1/2)), gastric emptying coefficient (GEC), lag phase (L-breath), and measured maximum (13)C excretion time (Tmax-measured) were calculated. The data was analyzed to determine the time for each phase of gastric emptying as follows: mean grinding time (MGT) = MRT(oral) - MRT(nasogastric), mean gastroduodenal transport time (MGDTT) = MRT(nasogastric) - MRT (nasoduodenal). Data was expressed as the mean +/- SE. The values of the parameters of MGT were 0.82 +/- 0.50 hr (MRT), 0.64 +/- 0.18 hr (T(1/2)), 0.51 +/- 0.24 hr (L-breath), -0.45 +/- 0.30 hr (GEC), and 49.2 +/- 8.0 min (Tmax-measured). The values of the parameters of MGDTT were 0.87 +/- 0.38 hr (MRT), 0.26 +/- 0.29 hr (T(1/2)), 0.92 +/- 0.36 hr (L-breath), 0.55 +/- 0.23 hr (GEC), and 63.33 +/- 8.16 min (Tmax-measured). The times required for the drug absorption and disposition were 1.60 0.20 hr (MRT), 1.03 +/- 0.24 hr (T(1/2)), 0.10 +/- 0.08 hr (L-breath), 3.72 +/- 0.46 hr (GEC), and 19.67 +/- 2.11 min (Tmax-measured). By varying the administration route of a test meal containing (13)C-octanoic acid, we may be able to assess each phase of the emptying of gastric solids in detail, thus leading to a better understanding of gastroduodenal motility.

Validity of 13C octanoic acid breath test for measurement of solid meal gastric emptying time in children

Background/Purpose It is important to establish a physiologic range of gastric emptying (GE) in children. Gastric emptying time measured with 99Tc-labeled solid meal (GE Tc) is the gold standard. Large-scale studies with GE Tc are ideal but not feasible because of radiation exposure. The 13C-labeled octanoic acid breath test (GE 13C) does not involve radiation and is suitable for large studies. The aim of this study was to validate GE 13C with GE Tc and to explore whether GE 13C could be used to establish a physiologic range of GE in children. Method Twenty-five healthy children underwent simultaneous GE Tc and GE 13C using a standardized solid test meal. The time taken for the stomach to empty half its content (T½ 13C) and solid lag phase (lag 13C) for GE 13C were computed from the fractional excretion of 13C in expired air. T½ 13C and lag 13C were compared with corresponding values obtained by GE Tc. Result Correlation coefficient between T½ 13C and T½ Tc was 0.69 ( P < .01; r = 0.92 if 3 outliers were omitted). Correlation coefficient between lag 13C and lag Tc was 0.39 ( P < .05). There was good agreement between the methods by the Bland Altman method. Conclusion There is good agreement between GE 13C and GE Tc. GE 13C can be safely used to establish the reference range of GE in healthy children.

Role of cholecystokinin in the gastric motor response to a meal in horses

To measure plasma cholecystokinin (CCK) activity and the effect of a CCK-1 receptor antagonist on accommodation of the proximal portion of the stomach, and subsequent gastric emptying, in horses after ingestion of high-fat or high-carbohydrate meals. 6 healthy adult horses with gastric cannulas. In the first study, horses were offered a high-fat (8% fat) or a high-carbohydrate (3% fat) pelleted meal of identical volume, caloric density, and protein content. Related plasma CCK-like activity was measured by radioimmunoassay (RIA). In a separate experiment, a horse was fed a grain meal with corn oil and phenylalanine, and plasma CCK activity was assessed by bioassay. A second study evaluated the effect of a CCK-1 receptor antagonist, devazepide (0.1 mg/kg, IV), on gastric accommodation and emptying following a meal of grain supplemented with either corn oil (12.3% fat) or an isocaloric amount of glucose (2.9% fat). Gastric tone was measured by a barostat and emptying by the (13)C-octanoic acid breath test. No plasma CCK-like activity was detected by RIA or bioassay before or after ingestion of meals. Preprandial devazepide did not alter the gastric accommodation response but did significantly shorten the gastric half-emptying time and time to peak breath (13)CO(2) content with the glucose-enriched meal. In horses, CCK participates in regulating the gastric motor response to a meal. Compared with other species, horses may be more responsive to carbohydrate than fat. A vagovagal reflex most likely mediates this regulation, with CCK as a paracrine intermediary at the intestinal level.

Frequent feeding delays the gastric emptying of a subsequent meal

To assess the suitability of the 13C-octanoic acid breath test for measuring gastric emptying in circumstances other than the post-absorptive state, a preliminary study was performed where 6 hourly spaced isoenergetic meals preceded the determination of gastric emptying of a subsequent 2 MJ meal. Emptying was measured in three individuals on four separate occasions, with a reproducibility of 8%. A crossover study was then conducted to test the hypothesis that meal frequency can modulate the gastric emptying of a subsequent meal, with the potential to influence appetite regulation. Sixteen subjects were fed to energy balance, receiving food either as 2 isoenergetic meals 3 h apart or 6 isoenergetic meals fed hourly. Gastric emptying of a subsequent 2 MJ meal was investigated. Visual analogue scales were used throughout to assess appetite. The maximum rate of gastric emptying was unchanged but the onset of emptying was delayed by the more frequent feeding pattern. There was no significant difference in subjective appetite before or after the test meal. In conclusion, short-term increases in feeding frequency delayed the gastric emptying of a subsequent meal, but significant effects on post-meal appetite could not be demonstrated.

Factors regulating gastric emptying in preterm infants

To determine whether osmolality, volume, or energy density affects gastric emptying rate (GE); whether simultaneously decreasing osmolality and increasing volume accelerates GE; and whether GE is related to any clinical and/or demographic characteristics. GE was measured using the (13)C-octanoic acid breath test in 17 infants of 25 to 30 weeks gestation in a tertiary care children's hospital. In study 1, the independent effects of osmolality, volume, and nutrient density were evaluated in 10 infants. In study 2, the combined effects of decreasing osmolality and increasing volume were evaluated in 7 infants. Results from all infants were used to investigate the relationships between clinical and demographic characteristics and GE. The statistical analysis comprised analysis of covariance, the (paired) Student t-test, the 1-sample Wilcoxon test, and regression analysis. Mean (+/- standard deviation) age was 27.7 +/- 14.6 days in study 1 and 34.1 +/- 14.0 days in study 2. Altering osmolality, volume, or energy density did not change GE, but simultaneously decreasing osmolality and increasing feeding volume accelerated GE by 18% versus standard feeding. GE correlated with gestational age at birth. Unlike in adults, in preterm infants osmolality, volume, or energy density individually do not affect GE. Reducing osmolality and increasing feeding volume increases GE. GE is related to gestational age at birth even at age 1 month.

Gastric emptying in patients with Type 2 diabetes mellitus and diabetes associated with mitochondrial DNA 3243 mutation using 13C-octanoic acid breath test

Although the 13C-octanoic acid breath test (OBT) has been applied to diabetic patients for assessing gastric emptying, such studies are still limited. Gastric emptying was measured using solid meal containing 13C-octanoic acid in 52 patients with Type 2 diabetes mellitus and 4 diabetic patients with mitochondrial DNA (mitDNA) 3243 mutation. Delayed gastric emptying was detected in 29% of patients with Type 2 diabetes mellitus, and multiple regression analysis showed that gastric emptying was independently associated with gastrointestinal symptoms and cardiac autonomic neuropathy. Gastric emptying was not related to gastric dysrhythmia in cutaneous electrogastrography (EGG). Diabetic patients with mitDNA 3243 mutation showed delayed gastric emptying. Because the pathogenesis of delayed gastric emptying is multifactorial in diabetic patients, the recently developed OBT is useful for studying gastric emptying in various clinical settings of diabetic patients.

Effects of Helicobacter pylori eradication therapy on gastric emptying measured using the 13C‐octanoic acid breath test and the acetaminophen method

The relationship between Helicobacter pylori eradication and gastric emptying has been reported; however, the effect of eradication therapy on gastric emptying is still unclear. This study evaluated the relationship between three gastric emptying techniques, the scintigraphic technique, the 13C-octanoic acid breath test, and the acetaminophen method, measured simultaneously, and the effect of H. pylori eradication therapy on gastric emptying and abdominal symptoms in patients with functional dyspepsia who were H. pylori positive. Fifty-three consecutive patients with positive H. pylori infection were enrolled in this study. In the first 14 patients, gastric emptying was measured using the three gastric emptying techniques. In 42 patients cured of H. pylori infection, the 13C-octanoic acid breath test and the acetaminophen method were performed before and 3 months after eradication. Significant correlations were found between the scintigraphic technique, the 13C-octanoic acid breath test, and the acetaminophen method. Gastric emptying determined by the 13C-octanoic acid breath test and the acetaminophen method was not changed after eradication, on average. In 14 (33.3%) patients a decrease in symptom score after eradication was observed. In four (9.5%) patients, accelerated gastric emptying after eradication may have led to a reduction in the abdominal symptoms. The 13C-octanoic acid breath test and the acetaminophen method are appropriate for investigating gastric emptying. A causal relationship between improvement of symptoms and accelerated gastric emptying was not found, and the efficacy of H. pylori eradication therapy in patients with functional dyspepsia was minimally exhibited.

Variability of the 13C‐octanoic acid breath test for gastric emptying of solids in healthy children

To assess the intra-individual variability of the 13C-octanoic acid breath test using non-dispersive infrared spectrometry for gastric emptying of solids in healthy children. A 13C-octanoic acid breath test was performed at least two times in 19 healthy children (age 12.4 +/- 2.7 years) 2-7 days apart to measure gastric emptying of solids. Breath samples were taken before eating a 13C-octanoic acid-labelled pancake and at 15-min intervals for the following 240 min. Breath samples were analysed using non-dispersive infrared spectrometry; 13C-recovery was used to calculate values for gastric half-emptying time (t(1/2)), gastric lag phase (t(lag)) and gastric emptying coefficient. Intra-individual variability of the parameters t(1/2), t(lag) and gastric emptying coefficient were expressed as coefficient of intrasubject variation. The mean coefficient of intrasubject variation of t(1/2) was 13.3 +/- 7.9% (range 2.5-29.6%; interindividual range 99-204 min; intra-individual range 5-84 min for t(1/2)). The mean coefficient of intrasubject variation of t(lag) was 13.6 +/- 7.5% (range 0.8-27.8%) (interindividual range 65-146 min; intra-individual range 1-50 min for t(lag)). The mean coefficient of intrasubject variation of gastric emptying coefficient was 12.5 +/- 6.8% (range 3.4-30.2%; interindividual range 2.3-3.9; intra-individual range 0.17-1.4 for gastric emptying coefficient). The coefficient of intrasubject variations of t(1/2), t(lag) and gastric emptying coefficient were independent of the values of t(1/2), t(lag) and gastric emptying coefficient. Gastric emptying in healthy children is characterized by a large inter- and intra-individual variability and is concordant with the results obtained with other techniques.

Botulinum A Toxin Injected into the Gastric Wall for the Treatment of Class III Obesity: A Pilot Study

Obesity represents a major public health problem in western countries. Initial studies suggest that injection of botulinum A toxin (Btx-A) into the antropyloric region inhibits propulsive contractions of the antral pump, with delay in gastric emptying, early satiety and weight loss. After approval by the University Ethics Committee, we prospectively evaluated 12 patients with class III obesity divided into 4 groups of 3 patients each. In groups I and II, 200 U Btx-A were injected into the antropyloric region at 8 and 16 sites, respectively. Groups III and IV received 300 U Btx-A into the antropyloric region at 16 and 24 sites, respectively. Body weight and gastric emptying time (GET) of solids and semi-solids using 13C-octanoic acid breath test and 13C-acetic acid breath test, respectively, were determined before and after injection over a period of 12 weeks. Pre- and post-treatment body weight or solid and semi-solid GET did not differ significantly between groups (P>0.05). All patients reported a feeling of early satiety. No adverse effects related to BtxA or complications resulting from the endoscopic procedure were observed. The injection of different doses of BtxA at different sites in the antropyloric region of patients with class III obesity did not interfere significantly with the solid and semi-solid GET or body weight of these individuals. However, early satiety was reported by all patients, the procedure was safe and no side-effects of the treatment were observed. Further controlled studies involving different methodologies regarding dosage of Btx-A and sites of injection are necessary.

Measuring Gastric Emptying: Comparison of 13C-Octanoic Acid Breath Test and Scintigraphy

The aim of this study was to compare scintigraphy, the standard method, and the (13)C-octanoic acid breath test (OBT) for measuring gastric emptying. Patients with functional dyspepsia (N = 21, 8 men and 13 women; ages, 40-75) underwent standardized dynamic scintigraphy and OBT. Scintigraphic images were obtained for 90 min and breath samples for 4 hr. The gastric half-emptying time for solids (T(1/2)) was calculated by two previously described mathematical models for the OBT samples: the nonlinear least-squares method and the geometrical method. T(1/2) was significantly longer measured by OBT than by scintigraphy (167 +/- 50 min for the nonlinear least-squares method (P < 0.05) and 185+/- 52 min for the geometrical method (P < 0.005) vs. 109 +/- 74 min for scintigraphy). No correlation appeared between T(1/2) measured by scintigraphy and T(1/2) measured by OBT (r = 0.26) for nonlinear least-squares method and (r = -0.13) for geometrical method). Furthermore, the correlation between the two mathematical models appeared to be low (r = 0.15). Although OBT is simple and safe, its correlation with scintigraphy appears to be weak. The usefulness of this test for measuring gastric emptying thus requires further validation.

Effect of cigarette smoking on gastric emptying of solids in Japanese smokers: a crossover study using the 13C-octanoic acid breath test

Cigarette smoking is associated with an increased risk of peptic ulcer and gastroesophageal reflux disease. Gastric emptying disorders may play a role in the development of these upper gastrointestinal diseases. Thus, studies examining a link between smoking and gastric emptying disorders have clinical relevance. This study was conducted to investigate the effect of smoking on gastric emptying of solids in Japanese smokers. The (13)C-octanoic acid breath test was performed in eight male habitual smokers on two randomized occasions (either sham smoking or actively smoking). The time vs (13)CO(2) excretion rate curve was mathematically fitted to a conventional formula of y (t) = m*k*beta*e(-k*t)*(1 - e(-k*t))(beta-1), and the parameters of k and beta were determined: under the crossover protocol, a larger (smaller) beta indicates slower (faster) emptying in the early phase, and a larger (smaller) k indicates faster (slower) emptying in the later phase. The half (13)CO(2) excretion time (t(1/2b) = -[ln(1 - 2(-1/beta))]/k) and the time of maximal (13)CO(2) excretion rate (t(max) = [lnbeta]/k) were also calculated. Between the two occasions, k, beta, t(1/2b), and t(max) were compared by the Wilcoxon signed-rank test. After smoking, k was significantly increased. No significant differences were found in beta, t(1/2), and t(max) between the two occasions. The increase in k suggests the acceleration of gastric emptying in the later phase. For the first time, this study has revealed that acute smoking speeds the gastric emptying of solids in Japanese habitual smokers.

Meal-induced gastric relaxation and emptying in horses after ingestion of high-fat versus high-carbohydrate diets

To evaluate the effect of ingestion of a high-carbohydrate versus a high-fat meal on relaxation of the proximal portion of the stomach and subsequent gastric emptying in horses. 6 healthy adult horses. The study consisted of 2 phases. In phase I, horses were offered a high-fat (8% fat) or a high-carbohydrate (3% fat) pelleted meal (0.5 g/kg) of identical volume, caloric density, and protein content. In phase II, meals consisted of a commercial sweet feed meal (0.5 g/kg) or this meal supplemented with corn oil (12.3% fat) or an isocaloric amount of glucose (2.9% fat). Proximal gastric tone was measured by variations in volume of an intragastric bag introduced through a gastric cannula and maintained with a constant internal pressure by an electronic barostat. Rate of gastric emptying was measured simultaneously with the 13C-octanoic acid breath test. Interaction between both techniques was studied in additional experiments. Meals with higher carbohydrate content induced a significantly more prolonged receptive relaxation of the proximal portion of the stomach than those with higher fat content, but the accommodation response was similar. Labeling the meals with the breath test marker influenced the accommodation response measured by the barostat. Gastric emptying rates were not significantly different between meals, although those high in carbohydrate initially emptied more slowly. In horses, in contrast to most species, dietary fat supplementation may not have a profound effect on gastric motility.

Effects of Intragastric Balloon on Gastric Emptying and Plasma Ghrelin Levels in Non-morbid Obese Patients

Intragastric balloons have been proposed to induce weight loss in obese subjects. The consequences of the balloon on gastric physiology remain poorly studied. We studied the influence of an intragastric balloon on gastric emptying and ghrelin secretion in non-morbid obese patients. 17 patients were included in the study, with mean BMI of 34.4 (range 30.1-40.0). The balloon was inserted under general anaesthesia and endoscopic control, inflated with 600 ml saline, and removed 6 months later. Body weight and gastric emptying (13C-octanoic acid breath test) were monitored while the balloon was in place and 1 month after removal. Ghrelin levels were measured just before balloon insertion and removal. Mean weight loss was 8.7 kg (range 0-21). Gastric emptying rates were significantly decreased with the balloon in place, and returned to pre-implantation values after balloon removal. Plasma ghrelin levels were significantly decreased (95% CI: -3.8 to -20.7 ng/ml), despite concomitant weight loss. Weight reduction was not correlated to the effect of the balloon on gastric emptying, but was significantly correlated to the ghrelin variations (r=0.668, 95% CI: 0.212-0.885). Gastric emptying rates and plasma ghrelin levels are decreased in the presence of intragastric balloon. Weight loss induced by the intragastric balloon is related to ghrelin variations, but not to gastric emptying. Ghrelin inhibition may explain part of the effect of the balloon on satiety.