Gut hormones, early dumping and resting energy expenditure in patients with good and poor weight loss response after Roux-en-Y gastric bypass.

OBJECTIVE: To identify factors contributing to the variation in weight loss after Roux-en-Y gastric bypass (RYGB). DESIGN: Cross-sectional study of patients with good (excess body mass index lost (EBL) >60%) and poor weight loss response (EBL <50%) >12 months after RYGB and a lean control group matched for age and gender. MATERIALS AND METHODS: Sixteen patients with good weight loss response, 17 patients with poor weight loss response, and eight control subjects were included in the study. Participants underwent dual energy X-ray absorptiometry scan, indirect calorimetry and a 9 h multiple-meal test with measurements of glucose, insulin, total bile acids (TBA), glucagon-like peptide (GLP)-1, peptide YY3-36 (PYY), cholecystokinin (CCK), ghrelin, neurotensin and pancreatic polypeptide (PP) as well as assessment of early dumping and appetite. RESULTS: Suppression of hunger was more pronounced in the good than the poor responders in response to the multiple-meal test (P=0.006). In addition, the good responders had a larger release of GLP-1 (P=0.009) and a greater suppression of ghrelin (P=0.037) during the test, whereas the postprandial secretion of CCK was highest in the poor responders (P=0.005). PYY, neurotensin, PP and TBA release did not differ between the RYGB-operated groups. Compared with control subjects, patients had exaggerated release of GLP-1 (P<0.001), PYY (P=0.008), CCK (P=0.010) and neurotensin (P<0.001). Early dumping was comparable in the good and poor responders, but more pronounced than in controlled subjects. Differences in resting energy expenditure between the three groups were entirely explained by differences in body composition. CONCLUSION: Favorable meal-induced changes in hunger and gut hormone release in patients with good compared with poor weight loss response support the role of gut hormones in the weight loss after RYGB.

Fast pouch emptying, delayed small intestinal transit, and exaggerated gut hormone responses after Roux-en-Y gastric bypass.

BACKGROUND: Roux-en-Y gastric bypass (RYGB) causes extensive changes in gastrointestinal anatomy and leads to reduced appetite and large weight loss, which partly is due to an exaggerated release of anorexigenic gut hormones. METHODS: To examine whether the altered passage of foods through the gastrointestinal tract after RYGB could be responsible for the changes in gut hormone release, we studied gastrointestinal motility with a scintigraphic technique as well as the secretion of the gut hormones glucagon-like peptide (GLP)-1 and peptide YY3-36 (PYY3-36 ) in 17 patients>1 year after RYGB and in nine healthy control subjects. KEY RESULTS: At meal completion, a smaller fraction of liquid and solid radiolabeled marker was retained in the pouch of RYGB patients than in the stomach of control subjects (P = 0.002 and P < 0.001, respectively). Accordingly, pouch emptying in patients was faster than gastric emptying in control subjects (P < 0.001 and P = 0.004, respectively liquid and solid markers). For the solid marker, small intestinal transit was slower in patients than control subjects (P = 0.034). Colonic transit rate did not differ between the groups. GLP-1 and PYY3-36 secretion was increased in patients compared to control subjects and fast pouch emptying of the liquid marker was associated with high gut hormone secretion. CONCLUSIONS & INFERENCES: After RYGB, the bulk of foods pass without hindrance into the small intestine, while the small intestinal transit is prolonged. The rapid exposure of the gut epithelium contributes to the exaggerated release of GLP-1 and PYY3-36 after RYGB.

The influence of sacral nerve stimulation on gastrointestinal motor function in patients with fecal incontinence.

BACKGROUND: Sacral nerve stimulation (SNS) is a well-established treatment for fecal incontinence of various etiologies. However, the mechanism of action remains unclear. The aim of the present study was to determine whether SNS affects gastric emptying, small intestinal transit or colonic transit times. METHODS: Seven patients with a permanently implanted sacral nerve stimulator participated in a double-blind randomized cross-over study. The patients were allocated to stimulation ON or OFF for two 7-day periods separated by at least 1week. On days 4-7 of each 7-day period, the patients were examined by gamma camera imaging to measure gastric emptying, small intestinal transit and colonic transit parameters of a radiolabeled, 1600 kJ mixed solid and liquid meal ingested on day 4. KEY RESULTS: Sacral nerve stimulation did not change gastric retention at 15 min, gastric mean emptying time, gastric half emptying time, small intestinal mean transit time or colonic geometric center after 24, 48 and 72 h. CONCLUSIONS & INFERENCES: Sacral nerve stimulation does not induce major changes in the propulsive capacity of the gastrointestinal tract in patients successfully treated for fecal incontinence with permanent sacral nerve stimulator.

Ghrelin receptor agonist (TZP-101) accelerates gastric emptying in adults with diabetes and symptomatic gastroparesis.

BACKGROUND: TZP-101 is a synthetic, selective ghrelin agonist in development for gastroparesis. AIM: To assess safety and effects of TZP-101 in diabetes patients with symptomatic gastroparesis. METHODS: Adults with type 1 or type 2 diabetes mellitus received placebo and TZP-101 (80, 160, 320 or 600 microg/kg) infusions in a cross-over manner following a radiolabelled meal. Blood glucose levels were stabilized using a hyperinsulinemic-euglycemic clamp. Primary endpoints were gastric half emptying and latency times. Secondary measures included assessment of gastroparesis symptoms and endocrine responses. RESULTS: Ten patients with type 1 (n = 7) or 2 (n = 3) diabetes, moderate-to-severe gastroparesis symptoms and > or =29% retention 4 h after a radiolabelled solid meal were enrolled. TZP-101 produced significant reductions in solid meal half-emptying (20%, P = 0.043) and latency (34%, P = 0.037) times vs. placebo. Reductions in overall postmeal symptom intensity (24%) and postprandial fullness (37%) following TZP-101 infusion were not statistically significant. Most adverse events were mild and self-limiting and there were no identifiable differences in numbers or types of adverse events between TZP-101 and placebo. CONCLUSIONS: This proof-of-concept study demonstrates that the ghrelin agonist TZP-101 is well-tolerated in diabetes patients with moderate-to-severe chronic gastroparesis and shows statistically significant improvements in gastric emptying.

A randomized, placebo-controlled, crossover, double-blind trial of the NK1 receptor antagonist aprepitant on gastrointestinal motor function in healthy humans.

BACKGROUND: Little is known about the role of tachykinins on human gastrointestinal motility and no data exist on the possible effect of an NK1 receptor antagonist. AIM: To examine the effect of an antiemetic dose of the selective NK1 receptor antagonist aprepitant on gastrointestinal propulsion in healthy humans. METHODS: Twelve healthy volunteers participated in a crossover, double-blind study. In random order, each volunteer had a 125-mg capsule of aprepitant or placebo on day 1 followed by an 80-mg capsule of aprepitant or placebo on days 2-5. Gamma camera imaging was used to measure gastric emptying, small intestinal transit and colonic transit of a radiolabelled, 1600-kJ mixed liquid and solid meal ingested on day 2. RESULTS: Aprepitant did not change gastric retention at 15 min, gastric half emptying time, gastric mean transit time, time to small intestinal transit of 10%, small intestinal mean transit time or colonic geometric centre after 24, 48 and 72 h. CONCLUSION: A 125-mg capsule of aprepitant followed by an 80-mg capsule of aprepitant each of the next 2-5 days did not induce major changes in the propulsive function of the gastrointestinal tract in the small number of healthy volunteers investigated.

Effect of intravenous infusion of glyceryl trinitrate on gastric and small intestinal motor function in healthy humans.

BACKGROUND: Glyceryl trinitrate is a donor of nitric oxide that relaxes smooth muscle cells of the gastrointestinal tract. Little is known about the effect of glyceryl trinitrate on gastric emptying and no data exist on the possible effect of glyceryl trinitrate on small intestinal transit. AIM: To examine the effect of intravenous infusion of glyceryl trinitrate on gastric and small intestinal motor function after a meal in healthy humans. METHODS: Nine healthy volunteers participated in a placebo-controlled, double-blind, crossover study. Each volunteer was examined during intravenous infusion of glyceryl trinitrate 1 microg/kg x min or saline. A gamma camera technique was used to measure gastric emptying and small intestinal transit after a 1600-kJ mixed liquid and solid meal. Furthermore, duodenal motility was assessed by manometry. RESULTS: Glyceryl trinitrate did not change gastric mean emptying time, gastric half emptying time, gastric retention at 15 min or small intestinal mean transit time. Glyceryl trinitrate did not influence the frequency of duodenal contractions, the amplitude of duodenal contractions or the duodenal motility index. CONCLUSIONS: Intravenous infusion of glyceryl trinitrate 1 microg/kg x min does not induce major changes in gastric or small intestinal motor function after a 1600-kJ meal in healthy volunteers.

Effect of sildenafil on gastric emptying and postprandial frequency of antral contractions in healthy humans.

BACKGROUND: Sildenafil is known to block phosphodiesterase type 5, which degrades nitric oxide-stimulated cyclic guanosine monophosphate, thereby relaxing smooth muscle cells in various organs. The effect of sildenafil on gastric motor function after a meal was investigated in healthy humans. METHODS: Ten healthy male volunteers (21-28 years) participated in a placebo-controlled, double-blind, cross-over study. In random order and on two separate days each volunteer ingested either 50 mg sildenafil (Viagra, Pfizer, New York, N.Y., USA) or placebo. A gamma camera technique was used to measure gastric emptying and postprandial frequency of antral contractions. RESULTS: The area under the curve of gastric retention versus time of liquid or solid radiolabelled marker was not changed by sildenafil intake, nor was the postprandial frequency of antral contractions affected by sildenafil. CONCLUSION: A single dose of 50 mg sildenafil does not change gastric emptying or postprandial frequency of antral contractions in healthy volunteers.

Effect of sustained-release isosorbide dinitrate on post-prandial gastric emptying and gastroduodenal motility in healthy humans.

Nitric oxide (NO) is an inhibitory neurotransmitter released by non-adrenergic and non-cholinergic neurons that innervate the smooth muscles of the gastrointestinal tract. We examined whether NO, derived from a sustained-release preparation of isosorbide dinitrate, influenced gastric emptying and gastroduodenal motility after a meal. Eleven healthy volunteers participated in a double-blind, placebo-controlled, cross-over study. Each subject ingested 40 mg isosorbide dinitrate orally as a sustained-release formulation or oral placebo, in random order. Gastric emptying and gastroduodenal motility were measured using scintigraphic and manometric techniques. Isosorbide dinitrate did not change the area under the curve of gastric retention versus time, and did not influence the frequency of antral contractions as assessed at 15-min intervals or the integrated duodenal motility index, as recorded over consecutive 15-min periods. A 40 mg single dose of sustained-released isosorbide dinitrate does not seem to alter gastric emptying or gastroduodenal motility after a meal.

Gastrointestinal transit after laparoscopic versus open colonic resection.

BACKGROUND: Multimodal rehabilitation with epidural analgesia, early oral nutrition and mobilization, and laxative use has decreased the duration of ileus after colonic surgery to about 2 days, as compared with the usual 3 to 5 days of rehabilitation required after open surgery and the slightly shorter time required with laparoscopic surgery. Gastrointestinal transit after colonic resection with laparoscopy or laparotomy was assessed. METHODS: In this study, 32 patients randomized to laparoscopic or open colonic resection received 4 MBq of 111indium diethylenetriamine pentaacetic acid, a tracer, at the end of surgery. Images of the abdomen were obtained 24 and 48 h postoperatively. An opaque abdominal dressing blinded care personnel and patients to the procedure. RESULTS: Defecation occurred on median day 2 postoperatively in both groups. At 48 h postoperatively, 53% of the tracer was excreted by patients in the laparoscopic group, as compared with 26% in the open group ( p > 0.05). CONCLUSION: Postoperative ileus and gastrointestinal transit normalized within 48 h after colonic resection in the patients who received multimodal rehabilitation. No significant difference was observed between the patients who underwent the laparoscopic procedure and those who underwent the open procedure.

Colorectal transport in normal defaecation.

OBJECTIVE: Colorectal luminal transport during defaecation can be assessed by means of scintigraphy. However, normal values remain to be established and inter- and intra-subjective variation is unknown. The aim of the study was to describe colorectal transport during normal defaecation by means of a new method for colorectal scintigraphy and to determine inter- and intrasubjective variation. METHODS: Thirty healthy volunteers (18 men and 12 women, age 22-46 years; median 31) took 2 MBq 111In on two consecutive days (days 0 and 1). On days 1 and 2 an abdominal scintigraphy was done before and after defaecation. Changes in colorectal contents were computed in two ways: firstly, assuming ordered evacuation, the extent of colorectal emptying was computed; secondly, antegrade and retrograde transport within the colorectum was computed for each colorectal segment. RESULTS: Median colorectal emptying during normal defaecation was 99% of the rectosigmoid (range: 60% of the rectosigmoid to complete emptying of the rectosigmoid, descending colon, transverse colon and 19% of the caecum/ascending colon). There was no difference between men (median 99% of the rectosigmoid) and women (98% of the rectosigmoid). Day to day variation was large (dispersion=52%) with a trend towards larger defaecation on day 2 than on day 1 (P = 0.09). Large antegrade and retrograde movements of colorectal contents were observed within the colorectum during defaecation. Antegrade transport involved the rectosigmoid (median 99%), the descending colon (median 53%), the transverse colon (median 46%), and the caecum/ascending colon (median 11%). Retrograde transport was mainly from the transverse colon and the descending colon. Colorectal emptying was significantly correlated to the subjective description (P < 0.01) but not to total gastrointestinal or segmental colorectal transit times determined by means of radioopaque markers. CONCLUSIONS: Colorectal scintigraphy before and after defaecation provides detailed information about colorectal emptying and intracolonic antegrade or retrograde transport during defaecation. Inter- and intraindividual variations are large and antegrade and retrograde transport within the colorectum is common.

Colorectal transport during defecation in patients with lesions of the sacral spinal cord.

Normal defecation involves reflexes between the colorectum and sacral spinal cord. Lesions of the conus medullaris or cauda equina interrupt such reflex arches and cause constipation. The aim of the study was to compare colorectal transport during defecation in patients with sacral spinal cord lesions and healthy volunteers. Ten patients with sacral spinal cord lesions (six men and four women, age 21-57 y, median = 36) and 16 healthy volunteers (10 men and six women, age 22-42 y, median = 30) took one or two doses of 111In-labelled polystyrene pellets perorally to mark colorectal contents. Abdominal scintigraphy was performed before and after defecation. Total colorectal emptying and segmental antegrade or retrograde transport was computed. Median colorectal emptying during normal defecation was 81% of the rectosigmoid (range: 53% of the rectosigmoid to complete emptying of the rectosigmoid and 40% of the descending colon) in healthy volunteers and 27% of the rectosigmoid (range: 0-44% of the rectosigmoid) in patients with conal/cauda equina lesions (P < 0.001). Median antegrade transport was 82% (control group) vs 27% (patients) of the rectosigmoid (P < 0.001), 38% vs 4% of the descending colon (P < 0.02), 13% vs 1% of the transverse colon (P = 0.28), and 4% vs 2% of the caecum/ascending colon (P = 0.76). It is concluded that damage to reflex arches between the colorectum and the sacral spinal cord significantly reduces emptying of the rectosigmoid and descending colon during defecation.

Exsanguination of the upper limb in healthy young volunteers.

Using a scintigraphic technique based on an autologous injection of 99mTc-labelled erythrocytes, we have evaluated the efficiency of different exsanguination procedures in the upper limb of ten healthy male volunteers. The methods were elevation alone, the use of the Esmarch bandage or a gauze bandage, the Pomidor roll-cuff, the squeeze method and the Urias bag. The various procedures gave the following median percentage reductions of blood volumes: elevation for 5 seconds 44%, 15 seconds 45%, 30 seconds 46%, 60 seconds 46% and 4 minutes 42%, the Esmarch bandage 69%, a gauze bandage 63%, the Pomidor roll-cuff 66%, the squeeze method 53%, and the Urias bag 57%. With regard to elevation alone no significant differences were found. All the external methods were significantly more effective than elevation alone. Overall, the squeeze method was found to be the best method of exsanguination before inflation of a tourniquet, because it is effective, fast, practical and inexpensive.

Short-term administration of glucagon-like peptide-2. Effects on bone mineral density and markers of bone turnover in short-bowel patients with no colon.

BACKGROUND: Glucagon-like peptide 2 (GLP-2) is a newly discovered intestinotrophic hormone. We have recently reported that a 5-week GLP-2 treatment improved the intestinal absorptive capacity of short-bowel patients with no colon. Additionally, GLP-2 treatment was associated with changes in body composition that included a significant increase in total body bone mass. This article describes the effect of GLP-2 on spinal and hip bone mineral density (BMD) and biochemical markers of bone turnover in these patients. METHODS: In an open-labelled pilot study, eight short-bowel patients (3M, 5F; mean age 49 years) with small-bowel resection and no colon received 400 microg s.c. of GLP-2 twice daily for 5 weeks. Four received home parenteral nutrition (mean length of residual jejunum 83 cm) and 4 did not (mean length of ileum resected 106 cm). The outcome measures were the mean percent change from baseline in spinal and hip BMD measured by dual-energy X-ray absorptiometry, changes in four biochemical markers of bone-turnover, PTH, 25-hydroxy vitamin-D, and the intestinal absorption of calcium. RESULTS: Mean +/- s(x) (SEM) percent changes in spinal and hip BMD were 1.1+/-0.4% (P < 0.05) and 1.9+/-0.8% (P = 0.06), respectively. The intestinal calcium absorption increased by 2.7% (P = 0.87). Serum ionized calcium increased in 5/8 patients with a concomitant decrease in serum PTH values. Three of the four markers of bone turnover decreased. CONCLUSION: A 5-week GLP-2 administration significantly increased spinal BMD in short-bowel patients with no colon. The mechanism by which GLP-2 affects bone metabolism remains unclear, but may be related to an increased mineralization of bone resulting from an improved intestinal calcium absorption.

Normal gastrointestinal transit after colonic resection using epidural analgesia, enforced oral nutrition and laxative.

BACKGROUND: Postoperative ileus usually lasts for 2-5 days after colonic surgery and may contribute to discomfort and pulmonary complications. With multimodal rehabilitation (epidural analgesia, early oral nutrition and mobilization, and laxative) defaecation occurs 1-2 days after colonic surgery. The aim of this study was to assess the transit rate of the entire gastrointestinal tract after colonic resection with multimodal rehabilitation. METHODS: Gastrointestinal motility was assessed by means of a scintigraphic method in 12 patients undergoing open colonic resection with multimodal rehabilitation and in 12 matched healthy volunteers. After intragastric or oral administration of 4 MBq 111In-labelled diethylenetriamine penta-acetic acid, images of the abdomen were taken at 24 and 48 h with a double-headed gamma camera. RESULTS: Patient and volunteer demographics were similar. The first defaecation occurred a median of 1 day after operation in the patients. Some 57 per cent of the tracer was excreted in faeces of patients and 53 per cent in faeces of volunteers (P > 0.05) within 48 h, indicating rapid recovery of the entire gastrointestinal motility after colonic resection with multimodal rehabilitation. CONCLUSION: This study documents early normalization of the entire gastrointestinal motility assessed by an 111In scintigraphic method in patients undergoing open colonic resection with a multimodal rehabilitation programme.

Gastrointestinal mean transit times in young and middle-aged healthy subjects.

To investigate the effects of age and gender on gastric, small intestinal and colonic mean transit times, a study was conducted in 32 healthy volunteers: eight young women (22-30 years), eight young men (20-28 years), eight middle-aged women (43-51 years) and eight middle-aged men (38-53 years). After ingestion of a meal containing 111Indium-labelled water and 99mTechnetium-labelled omelette imaging of the abdomen was performed at intervals of 30 min until all radioactivity was located in the colon and henceforth at intervals of 24 h until all radioactivity had cleared from the colon. Gastric, small intestinal and colonic mean transit times were calculated. The gastric, small intestinal and colonic mean transit times were significantly longer in women. Ageing was shown to accelerate the gastric and small intestinal transit significantly. In the group of men the colonic mean transit time was unaffected by age, but middle-aged women had a significantly slower colonic transit than young women. We therefore conclude that both age and gender have to be considered when reference values for gastric, small intestinal and colonic mean transit times have to be established.

Glucagon-like peptide 2 improves nutrient absorption and nutritional status in short-bowel patients with no colon.

BACKGROUND & AIMS: Glucagon-like peptide 2 (GLP-2) is intestinotrophic, antisecretory, and transit-modulating in rodents, and it is mainly secreted from the intestinal mucosa of the terminal ileum and colon after food ingestion. We assessed the effect of GLP-2 on the gastrointestinal function in patients without a terminal ileum and colon who have functional short-bowel syndrome with severe malabsorption of wet weight (>1.5 kg/day) and energy (>2.3 MJ/day) and no postprandial secretion of GLP-2. METHODS: Balance studies were performed before and after treatment with GLP-2, 400 microg subcutaneously twice a day for 35 days, in 8 patients (4-17 years from last bowel resection; 6 with Crohn's disease). Four patients received home parenteral nutrition (mean residual jejunum, 83 cm), and 4 did not (mean ileum resection, 106 cm). Biopsy specimens were taken from jejunal/ileal stomas, transit was measured by scintigraphy, and body composition was measured by dual-energy x-ray absorptiometry. RESULTS: Treatment with GLP-2 improved the intestinal absorption of energy 3.5% +/- 4.0% (mean +/- SD) from 49.9% to 53.4% (P = 0.04), wet weight 11% +/- 12% from 25% to 36% (P = 0.04), and nitrogen 4.7% +/- 5.4% from 47.4% to 52.1% (P = 0.04). Body weight increased 1.2 +/- 1.0 kg (P = 0.01), lean body mass increased 2.9 +/- 1.9 kg (P = 0.004), fat mass decreased 1.8 +/- 1.3 kg (P = 0.007), and 24-hour urine creatinine excretion increased (P = 0.02). The time to 50% gastric emptying of solids increased 30 +/- 16 minutes from 89 to 119 minutes (P < 0.05). Small bowel transit time was not changed. Crypt depth and villus height were increased in 5 and 6 patients, respectively. CONCLUSIONS: Treatment with GLP-2 improves intestinal absorption and nutritional status in short-bowel patients with impaired postprandial GLP-2 secretion in whom the terminal ileum and the colon have been resected.

Scintigraphic method for evaluating reductions in local blood volumes in human extremities.

We introduce a new method for evaluating reductions in local blood volumes in extremities, based on the combined use of autologue injection of 99mTc-radiolabelled erythrocytes and clamping of the limb blood flow by the use of a tourniquet. Twenty-two healthy male volunteers participated in the experiment. Evaluation of one versus two scintigraphic projections, trials for assessment of the reproducibility, a comparison of the scintigraphic method with a water-plethysmographic method and registration of the fractional reduction in blood volume caused by exsanguination as a result of simple elevation were carried out. No significant differences between results obtained by the use of one or two scintigraphic projections were found. The between-subject coefficient of variation was 14% in the lower limb experiment and 11% in the upper limb experiment. The within-subject coefficient of variation was 6% in the lower limb experiment and 6% in the upper limb experiment. We found a significant relation (r = 0.42, p = 0.018) between the results obtained by the scintigraphic method and the plethysmographic method. In fractions, a mean reduction in blood volume of 0.49+0.14 (2 SD) was found after 1 min of elevation of the lower limb and a mean reduction of 0.45+/-0.10 (2 SD) after half a minute of elevation of the upper limb. We conclude that the method is precise and can be used in investigating physiologic and pathophysiologic mechanisms in relation to blood volumes of limbs not subject to research previously.

Effect of obesity and major weight reduction on gastric emptying.

BACKGROUND: An enhanced gastric emptying rate might reduce the satiating effect of food and thereby promote obesity. Gastric emptying rate has previously been compared between obese and lean subjects with conflicting outcome. OBJECTIVE: Comparison of gastric emptying rate in lean and obese subjects before and after a major weight reduction. DESIGN: The study was designed as a case-control study comparing obese and lean subjects and a subsequent comparison of obese subjects before and after a dietary induced major weight reduction. METHOD: Gastric emptying rate following a solid test meal was estimated scintigraphically for 3 h using the left anterior oblique projection. SUBJECTS: Nineteen non-diabetic obese (mean BMI=38.7 kg/m2) and 12 lean (mean BMI=23.1 kg/m2) males matched for age and height. All obese subjects were re-examined after a mean weight loss of 18.8 kg (95% CI, 14.4-23.2) achieved by 16 weeks of dietary intervention followed by 8 weeks of weight stability. RESULTS: When comparing obese and lean subjects no differences were seen in overall 3 h emptying rate (30.3% per hour vs 30.5% per hour). However, a trend towards a higher percentage gastric emptying during the initial 30 min was seen in the obese when compared to lean subjects (24.0% vs 17.8% of the test meal; P=0.08). Weight loss was associated with a reduction in percentage gastric emptying during the initial 30 min (from 24.0% to 18.3% of the test-meal; P<0. 02), whereas the overall 3 h emptying rate was unaffected (30.3% vs 30.9% per hour). Neither initial or overall emptying rate differed between reduced-obese and lean subjects. CONCLUSION: Overall 3 h gastric emptying rate was similar in obese and normal weight males, and unaffected by a major weight loss. However, percentage gastric emptying during the initial 30 min for a solid meal appeared to be increased in obese males and was normalized after a major weight reduction.

Simplified scintigraphic methods for measuring gastrointestinal transit times.

To investigate whether simple transit measurements based on scintigraphy performed only 0, 2, 4 and 24 h after intake of a radiolabelled meal can be used to predict the mean transit time values for the stomach, the small intestine, and the colon, a study was conducted in 16 healthy volunteers. After ingestion of a meal containing 111indium-labelled water and 99mtechnetium-labelled omelette, imaging was performed at intervals of 30 min until all radioactivity was located in the colon and henceforth at intervals of 24 h until all radioactivity had cleared from the colon. Gastric, small intestinal and colonic mean transit times were calculated for both markers and compared with fractional gastric emptying at 2 h, fractional colonic filling at 4 h, and geometric centre of colonic content at 24 h, respectively. Highly significant correlations were found between gastric mean transit time and fractional gastric emptying at 2 h (111In: r=0.95, P<0.00001; 99mTc: r=0.96, P<0.00001), between small intestinal mean transit time and fractional colonic filling at 4 h (111In: r=-0.97, P<0.00001; 99mTc: r=-0.89, P<0. 00001), and between colonic mean transit time and geometric centre of colonic content at 24 h (111In: r=- 0.88, P<0.00001). We therefore conclude that reliable regional gastrointestinal transit times can be estimated from scintigraphic images taken 0, 2, 4 and 24 h after intake of radiolabelled markers.

Gastrointestinal motor function in patients with portal hypertension.

BACKGROUND: Existing data on gastric emptying and small-intestinal transit rates in portal-hypertensive patients are scarce and contradictory, and so far, the motor function of the colon has not been assessed in these patients. In this study we evaluated the propulsive effect of all main segments of the gastrointestinal tract in patients with well-characterized portal hypertension. METHODS: Eight patients with a postsinusoidal hepatic pressure gradient of at least 13 mmHg and eight age- and sex-matched healthy controls participated in the study. Gastric emptying, small-intestinal transit, and colonic transit rates were evaluated in all subjects by means of a gamma camera technique. The technique was also used to measure the frequency of antral contractions. RESULTS: No difference was observed in gastric mean emptying time or small-intestinal mean transit time of liquid and solid markers between patients and controls. After 24 h, however, the geometric center of the liquid marker had a more caudal localization in the colon of the patient group than in the controls (P = 0.04); that is, the patients had a faster colonic transit. No difference was found in the frequency of antral contractions 45 min after the test meal between patients and controls. CONCLUSIONS: These data suggest that the colonic transit is often accelerated in patients with portal hypertension, whereas the motor function of the stomach and the small intestine is unaffected.