Changes of gallbladder and gastric dynamics in patients with acute hepatitis A

Transient alterations of gallbladder morphology and dynamics have been reported in patients with during acute hepatitis A. The presence of dyspepsia also suggests involvement of gastric motility. During a 60-day follow-up, we investigated gallbladder and gastric motility in relation to dyspepsia in acute viral hepatitis A patients. Twenty patients were assessed at referral (day 0) and at days 7, 21, 42 and 60 and compared with 20 healthy volunteers. Gallbladder morphology and motility and gastric motility were assessed in the fasting and postprandial period by functional ultrasonography using a liquid test meal. Dyspeptic symptoms were scored. At day 0, fasting gallbladder volume was 5.9 +/- 1.3 mL, 32.6 +/- 4.6 mL, and 21.5 +/- 1.9 mL (mean +/- SE) in patients with gallbladder sludge (n = 7), without sludge (n = 13) and controls, respectively (P < 0.05 in sludge vs. no sludge and controls; P < 0.05 in no sludge vs. controls, ANOVA). Small fasting gallbladder volume in patients with sludge increased and sludge disappeared within 7 days. At day 0, patients with sludge also had increased thickness of fasting gallbladder wall and increased serum transaminase levels compared with patients without sludge and controls. Gallbladder contraction was similar in patients and controls. However, patients had delayed gastric emptying, which positively correlated with dyspepsia score. Gallbladder morphological changes observed in the acute phase of hepatitis A are transient and are associated with hepatocellular damage. Gastric emptying is delayed during the first week of disease and is associated with dyspeptic symptoms.     

Impaired gallbladder and gastric motility and pathological gastro-oesophageal reflux in gallstone patients

Impaired gallbladder motility is common in gallstone patients and might be associated with other gastrointestinal defects. Twenty patients with small stones in an opacified gallbladder at oral cholecystography and 20 healthy subjects homogeneous for sex, age and body size were studied by ultrasonography to assess gallbladder and gastric emptying simultaneously in response to a standard liquid meal (120 kcal, 11 g fat, 200 mL). The same subjects underwent ambulatory 24-h gastro-oesophageal pH monitoring. Dyspeptic symptoms were specifically investigated using a questionnaire. Gallstone patients had a significantly larger fasting (P < 0.05) and residual (P < 0.005) gallbladder volume with slower (P < 0.05) and less complete (anova , 0.001 < P < 0.05) gastric emptying than healthy control subjects. The speed of antral emptying was significantly correlated with the speed of gallbladder emptying (n = 40, r = + 0.31, P < 0.05). Pathological gastro-oesophageal reflux was present in 75% and 15% of patients and control subjects respectively (P < 0.05). Overall, 95% of gallstone patients had abnormal pH profiles resulting from pathological gastro-oesophageal reflux and/or prolonged gastric alkalinization. The speed of post-prandial antral emptying was significantly correlated with the duration of the longest gastro-oesophageal reflux episode (r = + 0.30, P < 0.03) and duodeno-gastric reflux episode (r = + 0.80, P < 0.02). Best predictors for gastric alkalinization were the following indices of gallbladder function: large fasting volume (P = 0.03), large ejection volume (P = 0.009) and slower emptying (P = 0.032). Gallbladder and gastric motility were similar in patients with (n = 12) and without (n = 8) dyspeptic symptoms. Pathological gastro-oesophageal reflux was found in 83% of dyspeptic patients and in 25% of patients without dyspepsia (P < 0.01). When reflux was present, it was significantly less in asymptomatic than in dyspeptic patients [time at pH < 4, median (range): 6.4% (3.2–22.6%) vs. 47.8% (2.1–87%), P < 0.05]. This study shows that a subgroup of gallstone patients with small—mainly asymptomatic—stones have impaired gallbladder and gastric motility as well as abnormal gastro-oesophageal pH-profiles. These findings point to the existence of multiple functional defects of the upper gastrointestinal tract in gallstone disease.     

Effects of a novel cholecystokinin (CCK) receptor antagonist, MK-329, on gallbladder contraction and gastric emptying in humans. Implications for the physiology of CCK.

To explore the physiology of cholecystokinin (CCK) in humans, we investigated the effect on gallbladder contraction and gastric emptying of a recently developed CCK receptor antagonist, MK-329. In a double-blind, four-period crossover study eight subjects received single doses of 0.5, 2, or 10 mg MK-329, or placebo, followed by an intravenous infusion of CCK-8 (30 pmol/kg.h). In placebo-treated subjects gallbladder volumes decreased on average to 43% of initial volumes after 2 h of CCK infusion. MK-329 caused a dose-dependent inhibition of CCK-stimulated gallbladder contraction with 10 mg producing complete blockade (P less than 0.01, cf. placebo). Gallbladder contraction and gastric emptying rates after a mixed meal were then measured in a two-period crossover study. Subjects received placebo or 10 mg of MK-329 2 h before eating. Gastric emptying of both solids and liquids was measured simultaneously by gamma scintigraphy. In placebo-treated subjects plasma CCK levels increased postprandially to 2.3 pM, gallbladder volumes decreased 68.4 +/- 3.8% (SE), and the times for 50% emptying of liquids and solids from the stomach were 58 +/- 10 and 128 +/- 8 min, respectively. In MK-329-treated subjects there was a marked elevation in peak CCK levels to 13.8 pM (P less than 0.01, cf. placebo), and gallbladder contraction was completely inhibited. Solid and liquid emptying rates were unaffected. These findings demonstrate that (a) MK-329 is a potent, orally active antagonist of CCK in humans, and (b) CCK is the major regulator of postprandial gallbladder contraction. These data also support the concept of negative feedback regulation of CCK secretion and suggest that mechanisms other than CCK play a dominant role in the regulation of postprandial gastric emptying rates.     

Effect of rectal distension on gallbladder emptying and circulating gut hormones

BACKGROUND: Abnormalities of upper gut motility, including a delay of gastric emptying and small bowel transit, found in patients with constipation may be secondary to factors originating in the colon or rectum as a result of faecal stasis. The aim was to determine if stimulation of mechanosensory function by rectal distension affects postprandial gallbladder emptying and release of gastrointestinal peptides participating in control of upper gut motility. MATERIALS AND METHODS: Eight healthy volunteers were studied with an electronic barostat and a plastic bag positioned in the rectum. Intrabag pressure was maintained at minimal distension pressure + 2 mmHg on one occasion and on a pressure that induced a sensation of urge on the other. Gallbladder volume and plasma concentrations of cholecystokinin (CCK), pancreatic polypeptide (PP) and peptide YY (PYY) were measured before and after ingestion of a 450-kcal mixed liquid meal. RESULTS: Rectal distension enhanced maximum gallbladder emptying from 66 +/- 7% to 78 +/- 5% (P < 0.05). Distension tended to increase integrated plasma PYY from 77 +/- 30 pM min to 128 +/- 40 pM min in the first hour after the meal (P = 0.08) and it suppressed integrated plasma PP from 1133 +/- 248 pM min to 269 +/- 284 pM min in the second hour (P < 0.05). Integrated plasma CCK concentrations were not significantly affected. CONCLUSION: Mechanosensory stimulation of the rectum enhances postprandial gallbladder emptying and influences postprandial release of gut hormones involved in the regulation of gastrointestinal motility in healthy subjects. These mechanisms may play a role in the pathogenesis of the upper gastrointestinal motor abnormalities observed in constipated patients.     

Dyspepsia in AIDS is correlated to ultrasonographic changes of antral distension.

OBJECTIVES: Patients with acquired immune deficiency syndrome (AIDS) frequently complain about dyspeptic symptoms. We set out to test whether changes in antral emptying or antral distension may account for these dyspeptic symptoms in AIDS. METHODS: We studied antral emptying in ten patients with HIV infection (CDC 1993 classification stage C) by means of an established real-time ultrasonographic method. Organic abdominal lesions had been excluded. Six upper gastrointestinal symptoms were evaluated using a score ranging from 0 to 3. Fifteen subjects without any abdominal complaints and without any abdominal history served as controls. Antral cross sectional area was measured after an overnight fast and at 0, 15, 30, 45, 60, 90, 120 min after an semisolid test meal. Antral postprandial distension was expressed using an antral expansion ratio (postcibal antral area/fasting antral area). Gastric emptying of the test meal was derived from the measurement of the area under the postcibal antral distension curve (AUC). RESULTS: Fasting antral cross sectional area and AUC (gastric emptying) were similar in both groups. Antral postprandial expansion tended to be lower in AIDS patients compared to controls (mean+/-S.D.): 288+/-84 versus 397+/-156%; P=0.08. In AIDS patients the symptom score of dyspepsia showed a positive correlation (r=0.55; P<0.05) with fasting antral area and a negative correlation (r=-0.62; P<0.05) with postprandial expansion. No signs of autonomic neuropathy were to be found in the AIDS patients tested in this study. CONCLUSION: A wider fasting antral cross sectional area and an impaired antral postprandial expansion are related to dyspeptic symptoms in AIDS patients. This suggests the same relationship between dyspeptic symptoms and disturbed antral distension as seen in other patients with functional dyspepsia.     

Gastric myoelectrical activity and gastrointestinal motility in patients with functional dyspepsia

Abstract. The aim of our study was to examine the prevalence of gastric myoelectrical disturbances in relation to gastrointestinal motility abnormalities in patients with functional dyspepsia, using simultaneous electrogastrography and antroduodenojejunal manometry. We carried out electrogastrography in 20 patients with functional dyspepsia and in 20 healthy volunteers. In 10 of these patients and in 10 of the volunteers antroduodenojejunal manometry was performed simultaneously. Apart from a higher postprandial power content of the 3 cycles per minute (cpm) component in the patients (1263 ± 317 and 393 ± 101 μV², respectively; P = 0.016), no differences in the electrogastrographic variables were found between the groups. In the manometric part of the study, postprandial antral hypoactivity was not a prominent finding. Instead, small intestinal hyper-activity was found in the dyspeptic patients, with both a higher frequency and amplitude of the contractions ( P < 0.05). This hyperactivity often consisted of bursts, which were significantly more frequent in patients than in control subjects (total duration of burst activity 25.6 ± 6.4 and 6.0 ± l.7 min, respectively; P = 0.013). A positive correlation was found between the frequency of the gastric electrical control activity and the antral contraction frequency ( P = 0.006), between the power content of the electrographic signal and the antral contraction amplitude ( P = 0.025), and between the postprandial/fasting electrographic power ratio and the antral motility index ( P = 0.007). In conclusion, gastric myoelectrical activity is minimally disturbed in patients with functional dyspepsia. Motor abnormalities, especially small intestinal hyperactivity, are more likely to play a prominent role in the genesis of dyspeptic symptoms.     

Correlation between simultaneous scintigraphic and ultrasonographic measurement of gastric emptying in patients with type 1 diabetes mellitus.

OBJECTIVE: To compare scintigraphic measurements of total stomach emptying of a semisolid meal with ultrasonographic measurements of changes in antral area as estimates of antral emptying in type 1 diabetic patients. METHODS: Eleven patients with insulin-dependent diabetes mellitus were studied with simultaneous measurements of gastric emptying by scintigraphy and ultrasonography. Patients were imaged immediately after ingestion (time 0) and every 15 minutes over 120 minutes. The gastric emptying rate was expressed as percent reduction in antral cross-sectional area from 15 to 90 minutes after meal ingestion. RESULTS: Ultrasonographic measurements showed a postprandial maximal antral area at 15 minutes, continuously decreasing with time, and reaching a plateau 45 to 90 minutes after the end of meal ingestion, whereas the scintigraphic counts attained their maximum immediately after the meal and began to fall thereafter. Between 15 and 90 minutes, the residual radioactivity and antral ultrasonographically measured distension curves were concordant. The curves then showed a tendency toward deviation for the last 15 minutes (median, 51% versus 59% at 105 minutes and 40% versus 57% at 120 minutes, respectively). A strong significant correlation could be seen between the ultrasonographic gastric emptying rate and scintigraphic half-time values (r = -0.94; P < .001). Comparing scintigraphic and ultrasonographic half-time values showed a systematic measurement error of 9.9 minutes and a random measurement error of 18.6 minutes. CONCLUSIONS: The use of standardized real-time ultrasonography to determine the gastric emptying rate of semisolid meals in diabetic patients, with the use of the change in gastric antral cross-sectional area in a single section of the stomach 15 and 90 minutes postprandially, offers a valid method for clinical practice.     

Hyperglycemia attenuates the gastrokinetic effect of erythromycin and affects the perception of postprandial hunger in normal subjects.

OBJECTIVE: The major aims of this study were to determine in normal subjects whether the effects of erythromycin on gastric emptying, postprandial hunger, and fullness are modified by the blood glucose concentration. RESEARCH DESIGN AND METHODS: A total of 10 normal subjects (aged 20-39 years) underwent concurrent measurements of gastric emptying, blood glucose, hunger, and fullness on four separate occasions: twice during euglycemia (approximately 4 mmol/l) and twice during hyperglycemia (approximately 15 mmol/l). Either erythromycin (3 mg/kg) or saline (0.9%) was administered intravenously immediately before ingestion of a radioisotopically labeled solid meal. RESULTS: Gastric emptying was slower (P < 0.0001) during hyperglycemia when compared with euglycemia after both erythromycin and saline administration. During hyperglycemia, erythromycin reduced the lag phase (77.8 +/- 12.6 vs. 20.3 +/- 7.3 min; P < 0.05) but had no effect on the postlag emptying rate (0.32 +/- 0.077% per min vs. 0.24% per min). Hunger decreased (P < 0.001) and fullness increased (P < 0.001) after the meal. Postprandial hunger was less during hyperglycemia after saline infusion (P < 0.05) but not after erythromycin. Hunger was greater after erythromycin during both hyperglycemia and euglycemia (P < 0.05). CONCLUSIONS: At a blood glucose concentration of approximately 15 mmol/l, 1) gastric emptying of a solid meal is slower, when compared with euglycemia, even after administration of erythromycin; 2) the effect of erythromycin on gastric emptying of a solid meal is attenuated; and 3) the perception of postprandial hunger is reduced.     

Sonographic study of postprandial gallbladder emptying and common bile duct changes in patients with diabetes or cholelithiasis

The aim of our study was to evaluate postprandial emptying of the gallbladder and common bile duct (CBD) in 20 patients with gallstones and in 20 diabetic patients with or without autonomic neuropathy. Gallbladder fasting volume was significantly increased in patients with multiple stones. Diabetics with autonomic neuropathy showed a decreased gallbladder emptying rate. CBD size did not show any significant change in all groups examined.     

Noninvasive breath tests can detect alterations in gastric emptying in the mouse

BACKGROUND: Noninvasive breath tests may have significant utility for the measurement of gastric emptying in mice, but the tests' sensitivity for detection of changes in gastric emptying has not been evaluated. MATERIALS AND METHODS: Hydroxypropyl methyl cellulose was incorporated into a liquid meal to delay gastric emptying, and mice were injected with erythromycin to accelerate emptying of a liquid or solid meal. All test meals were labelled with (13)C-acetic acid or (13)C-octanoic acid. Breath samples collected at intervals were analysed for (13)CO(2) content, and gastric emptying rates were calculated from the resultant (13)CO(2) excretion curves. RESULTS: As predicted, hydroxypropyl methyl cellulose slowed emptying compared with water (14.21 +/- 0.94 min vs. 9.17 +/- 0.47 min, P < 0.001), while erythromycin treatment accelerated emptying of liquids (10.96 +/- 0.78 min vs. 16.41 +/- 1.94 min, P < 0.05) and solids (108.81 +/- 18.06 vs. 157.95 +/- 12.01 min, P < 0.05) compared with the saline injected controls. CONCLUSIONS: These data indicate that in mice the breath test is sensitive enough to detect differences in gastric emptying induced by meal composition and pharmacological agents. Noninvasive measurement of gastric emptying in mice will be useful as a method to evaluate the effect of nutrients or drugs on the motility of the gastrointestinal tract.     

Measurement of gastric emptying by standardized real-time ultrasonography in healthy subjects and diabetic patients.

The aim of this study was to simplify and standardize a reproducible, well-tolerated and clinically applicable method for the assessment of gastric emptying rate by real-time ultrasonography. A total of 33 subjects were examined, including 19 healthy subjects and 14 patients with insulin-dependent diabetes mellitus and clinically suspected delayed gastric emptying. Measurements of the gastric antrum were taken in the supine position and in relation to internal landmarks to obtain a standardized cross-sectional image producing the area of a selected slice of the antrum. Diabetic patients were examined on the condition that the fasting blood glucose level was 3.5 to 9.0 mmol/l. Gastric emptying rate was estimated and expressed as the percentage reduction in antral cross-sectional area from 15 to 90 min after the ingestion of a standardized semisolid breakfast meal (300 g rice pudding, 330 kcal). Interobserver and intraobserver measurement errors were assessed, as was the significance of age and sex on gastric emptying. In comparison to healthy subjects, diabetic patients showed significantly wider median values of the 90 min postprandial antral area, but only a mild tendency toward greater dilation of the gastric antrum prior to and 15 min after meal ingestion. The median value of gastric emptying rate in these diabetic patients was estimated at 29%, which was less than half of that in the healthy subjects (63%). Statistically the difference was highly significant. Interpersonal variability of gastric emptying rate and antral areas was large for both groups. Measurements of gastric emptying rate gave highly reproducible results on separate days and from different observers (interobserver systematic measurement error 0.3% and random measurement error 10.9%; intraobserver systematic measurement error 3.6% and random measurement error 9.5%). No difference in gastric emptying rate was found related to age or sex. We conclude that the use of standardized real-time ultrasonography to determine gastric antral cross-sectional area in a single section of the stomach is a valid method for estimating gastric emptying rate.     

Prevalence of delayed gastric emptying in diabetic patients and relationship to dyspeptic symptoms: a prospective study in unselected diabetic patients

OBJECTIVE: Data on the prevalence of abnormal gastric emptying in diabetic patients are still lacking. The relation between gastric emptying and dyspeptic symptoms assessed during gastric emptying measurement has not yet been investigated. The aim was to investigate the prevalence of delayed gastric emptying in a large cohort of unselected diabetic patients and to investigate the relation between gastric emptying and gastrointestinal sensations experienced in the 2 weeks before and during the test meal, prospectively. RESEARCH DESIGN AND METHODS: Gastric emptying was evaluated in 186 patients (106 with type 1 diabetes, mean duration of diabetes 11.6 +/- 11.3 years) using 100 mg (13)C-enriched octanoic acid added to a solid meal. RESULTS: Gastric emptying was significantly slower in the diabetic subjects than in the healthy volunteers (T(50): 99.5 +/- 35.4 vs. 76.8 +/- 21.4 min, P < 0.003; Ret(120 min): 30.6 +/- 17.2 vs. 20.4 +/- 9.7%, P < 0.006). Delayed gastric emptying was observed in 51 (28%) diabetic subjects. The sensations experienced in the 2 weeks before the test were weakly correlated with the sensation scored during the gastric emptying test. Sensations assessed during the gastric emptying test did predict gastric emptying to some extent (r = 0.46, P < 0.0001), whereas sensations experienced in the previous 2 weeks did not. CONCLUSIONS: This prospective study shows that delayed gastric emptying can be observed in 28% of unselected patients with diabetes. Upper gastrointestinal sensations scored during the gastric emptying tests do predict the rate of gastric emptying to some extent and sensation experienced during daily life does not.     

Role of the gastric phase in fat-induced gallbladder contraction and cholecystokinin secretion in humans

The present study was undertaken to investigate the role of the gastric phase of fat-induced gallbladder contraction and endogenous cholecystokinin (CCK) secretion in humans. Gallbladder emptying, measured by cholescintigraphy, and endogenous CCK secretion, measured by radioimmunoassay, were studied in healthy subjects after both intragastric and intra-intestinal administration of corn oil. In addition, patients with partial gastrectomy were investigated to study the effect of accelerated gastric emptying. In the healthy subjects, intragastric administration of fat resulted in a significantly (P less than 0.05) later increase in plasma CCK levels (20 +/- 2 min) compared to intraintestinal fat (5 +/- 1 min). Similarly, the onset of gallbladder emptying was significantly (P less than 0.05) delayed after intragastric fat (20 +/- 2 min) compared to intestinal fat (10 +/- 1 min). In the healthy subjects the integrated plasma CCK response to intragastric fat was significantly (P less than 0.005-P less than 0.01) reduced from 10 to 30 min. In the patients with partial gastrectomy the rise in plasma CCK (10 +/- 1 min) and the onset of gallbladder emptying (15 +/- 2 min) were in the same range after intra-intestinal and intragastric fat. No significant differences in plasma CCK levels, integrated CCK response or gallbladder emptying were found in the patients according to the site of fat application. It is concluded that endogenous CCK secretion and gallbladder emptying in response to intragastric fat are significantly delayed in healthy subjects but not in patients with partial gastrectomy, in whom gastric emptying is accelerated.(ABSTRACT TRUNCATED AT 250 WORDS)     

Difference in leptin response to a high-fat meal between lean and obese men

The aim of this study was to compare the leptin responses to a high-fat meal in lean and obese men, and to investigate whether the net leptin response (area under the incremental curve) after the meal was related to the thermic effect of food (TEF). Blood samples were collected after an overnight fast and every 2 h for 8 h after a high-fat breakfast (60 g of fat/m(2) body surface area) in 12 lean and 12 obese men for determination of glucose, insulin and leptin. The TEF was calculated as postprandial energy expenditure minus fasting energy expenditure, as measured by indirect calorimetry. Fasting plasma glucose levels were similar in lean and obese men, and increased in the same way after the meal. Fasting and postprandial plasma insulin concentrations were significantly greater in obese than in lean men (P<0.01 and P<0.05 respectively). Accordingly, obese men showed a significantly higher net insulin response than lean subjects (P<0.001). Fasting plasma leptin levels were greater in obese than in lean men (P<0.001). After the meal, plasma leptin increased significantly in lean men, whereas it decreased in obese men (group by time interaction, P<0.01). The net response of leptin was greater in lean than in obese men, but this did not reach statistical significance (P=0.07). Moreover, the TEF was similar in the two groups. No significant relationship was observed between either the net insulin response or the net leptin response after the high-fat meal and the TEF of lean subjects (-0.05 相似文献   

Ultrasonographic assessment of gallbladder bile exchanges in healthy subjects and in gallstone patients.

Impaired gallbladder motility may contribute to gallstone pathogenesis by providing time for nucleation and aggregation of cholesterol crystals. Simultaneous scintigraphic-ultrasonographic techniques have been proposed to assess alternating phases of gallbladder emptying and filling. To evaluate patterns of gallbladder motility and of postprandial bile flow by means of a single ultrasonographic technique, 12 healthy volunteers and 20 gallstone patients underwent minute-by-minute gallbladder ultrasonography for 3 h postprandially. Mathematical analysis of volume measurements was used to estimate hepatic and cholecystic bile flux through the gallbladder. Compared to controls, gallstone patients showed greater amounts of unexchanged cholecystic-to-hepatic bile (11% vs. 1%, p <.001) and most of them showed impaired gallbladder washout efficacy. Utrasonographic values of bile exchanges were similar to those derived from scintigraphic-sonographic studies in comparable groups of subjects. This study provides new ultrasonographic variables, which better express gallbladder bile retention in gallstone patients and strongly discriminate gallstone patients from controls.     

Diminished functional association between proximal and distal gastric motility in critically ill patients

OBJECTIVE: This study examined the effects of critical illness on the relationship between proximal and distal gastric motor activity during fasting and duodenal nutrient stimulation. DESIGN: Prospective, case-controlled study. PATIENTS AND PARTICIPANTS: Ten critically ill patients and ten healthy volunteers. INTERVENTIONS: Concurrent proximal gastric (barostat) and antro-pyloro-duodenal (manometry) motility were recorded during fasting and during two 60-min duodenal nutrient infusions (Ensure at 1[Symbol: see text]kcal/min and 2[Symbol: see text]kcal/min) in random order, separated by a 2-h wash-out period. RESULTS: Baseline proximal gastric volumes were similar between the two groups. At 10[Symbol: see text]min nutrient-induced fundic relaxation was lower in patients than healthy subjects (45[Symbol: see text]+/-[Symbol: see text]26 vs. 196[Symbol: see text]+/-[Symbol: see text]29[Symbol: see text]ml). In patients the frequency and volume amplitude of fundic waves were also lower. There were fewer propagated antral waves in patients than in healthy subjects during both fasting and nutrient infusion. These were more retrograde, shorter in length and associated with a pyloric contraction. The proportion of fundic waves followed by a distally propagated antral wave was significantly less in patients (0%, 0-8%) than controls 36% (11-44%). CONCLUSIONS: In critical illness, in addition to impairment of proximal and distal gastric motor activity, the association between the two gastric regions is abnormal. This disturbance may interfere with meal distribution and further contribute to slow gastric emptying in these patients.     

Thermic effect of food at rest, during exercise, and after exercise in lean and obese men of similar body weight.

The thermic effect of food at rest, during 30 min of cycle ergometer exercise, and after exercise was studied in eight lean (mean +/- SEM, 10 +/- 1% body fat, hydrostatically-determined) and eight obese men (30 +/- 2% body fat). The lean and obese mean were matched with respect to age, height, weight, and body mass index (BMI) to determine the relationship between thermogenesis and body composition, independent of body weight. All men were overweight, defined as a BMI between 26-34, but the obese had three times more body fat and significantly less lean body mass than the lean men. Metabolic rate was measured by indirect calorimetry under four conditions on separate mornings, in randomized order, after an overnight fast: 3 h of rest in the postabsorptive state; 3 h of rest after a 750-kcal mixed meal (14% protein, 31.5% fat, and 54.5% carbohydrate); during 30 min of cycling and for 3 h post exercise in the postabsorptive state; and during 30 min of cycling performed 30 min after the test meal and for 3 h post exercise. The thermic effect of food, which is the difference between postabsorptive and postprandial energy expenditure, was significantly higher for the lean than the obese men under the rest, post exercise, and exercise conditions: the increments in metabolic rate for the lean and obese men, respectively, were 48 +/- 7 vs. 28 +/- 4 kcal over 3 h rest (P less than 0.05); 44 +/- 7 vs. 16 +/- 5 kcal over 3 h post exercise (P less than 0.05); and 19 +/- 3 vs. 6 +/- 3 kcal over 30 min of exercise (P less than 0.05). The thermic effect of food was significantly negatively related to body fat content under the rest (r = -0.55), post exercise (r = -0.66), and exercise (r = -0.58) conditions. The results of this study indicate that for men of similar total body weight and BMI, body composition is a significant determinant of postprandial thermogenesis; the responses of obese are significantly blunted compared with those of lean men.     

Short-term inhibition of duodenal tryptic activity does not affect human pancreatic, biliary, or gastric function

Existence of feedback inhibition of pancreatic secretion by luminal pancreatic trypsin in humans is controversial. We examined the effect of duodenal tryptic activity on pancreatic, biliary, and gastric functions. In six healthy volunteers, gastric acid secretion and emptying and the secretion of pancreatic enzymes, bicarbonate, and bile acids into the duodenum were measured for 7 hr with a double-marker perfusion technique. Each experiment consisted of six test periods. The effects of the addition of active and inactive aprotinin to duodenal saline perfusion were determined during fasting and after administration of a saline test meal. We found that (1) aprotinin eliminated tryptic activity in the preprandial state and reduced it by more than 95% during meal periods; (2) compared to inactivated aprotinin, no differences in the outputs of bicarbonate, amylase, lipase, chymotrypsin, and bile acids occurred during preprandial or postprandial aprotinin periods; and (3) gastric acid secretion, emptying, and duodenogastric reflux were similar during aprotinin and inactivated-aprotinin perfusions. We conclude that short-term, almost complete reduction of intraduodenal tryptic activity does not alter exocrine pancreatic secretion or gastric function in the unstimulated state or in response to a moderate stimulation by a saline test meal. Therefore the importance of negative feedback control of pancreatic secretion by acute alteration of intraduodenal tryptic activity must be questioned in healthy humans.     

Acute insulin administration does not affect plasma leptin levels in lean or obese subjects

Abstract. Whether leptin levels are related to insulin sensitivity or subject to acute regulation by insulin is not known. In 12 obese [body mass index (BMI) = 34.0 ±1.5 kg m^-2] and 12 lean (BMI = 22.2 ±0.6 kg m^-2) non-diabetic subjects, plasma leptin concentrations were measured in the fasting state and during 2 hours of euglycaemic hyperinsulinaemia (˜600 pmol L^-2). Fasting plasma leptin was significantly higher in obese (26.6 ±3.2) than in lean subjects (6.4 ±1.2 ng mL^-1, P = 0.0001), and in women (21.1 ±3.3) than in men (7.3 = 2.3 ng mL^-1, P = 0.01). In univariate analysis, fasting plasma leptin was strongly related to all anthropometric measures (body weight, fat mass, percent fat mass, waist and hip circumferences). In multiple regression, per cent adiposity, hip circumference and duration of obesity explained 90% of the variability in fasting leptin concentrations. Fasting and stimulated (OGTT) insulin levels, insulin sensitivity (22.6 ±1.9 vs 36.7 ±2.0 μmol min^-1 kg^-1 in lean and obese subjects, respectively, P < 0.0001), glucose area, and serum triglycerides were positively related to fasting plasma leptin concentrations; none of these associations, however, was statistically significant after adjusting for BMI. During the clamp, plasma leptin concentrations remained constant in both lean and obese subjects. We conclude that neither insulin levels nor sensitivity relate to leptin levels independently of fat mass, and that leptin is not subject to acute (2 hours) regulation by insulin in lean or obese humans.     

Gallbladder emptying in diabetic patients and control subjects assessed by real-time ultrasonography and cholescintigraphy: a methodological comparison

Gallbladder motor function was studied in nine diabetic patients and nine control subjects matched for sex, age, and weight. None of the subjects had gallstones. Two different techniques were employed: real-time ultrasonography and cholescintigraphy using 99mTc-HIDA as imaging agent. Gallbladder volumes were determined sonographically by using three dimensions: length, lateral, and anterior-posterior diameters. Gallbladder emptying was stimulated by a standard test drink (Biloptin). Ejection fraction was computed and the results obtained by both techniques were compared. Fasting and residual gallbladder volumes after contraction were significantly larger in the diabetic patients than in the control subjects (15.9 +/- 7.6 cm3 vs. 2.3 +/- 1.3 cm3, p less than .0007; and 9.2 +/- 9.8 cm3 vs. 0.7 +/- 0.7 cm3, p less than .0007). Ejection fractions (ultrasonography/cholescintigraphy) were lower in the diabetic patients compared with the control subjects (59.9 +/- 26.6% and 63.1 +/- 23.2% vs. 73.2 +/- 23.8% and 75.3 +/- 24.8%), however, this difference was not statistically significant. Sonographically and scintigraphically determined ejection fractions were closely correlated (r = 0.90, p less than .00005).