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Biomedical subjects

M Ledeboer

Publications and source records attributed to M Ledeboer.

9 recordsLinked to original sources

Prospective study of the effect of the Belsey Mark-IV fundoplication on reflux mechanisms.

BACKGROUND: Transient lower esophageal sphincter relaxations (TLESRs) are the major mechanism permitting gastroesophageal reflux (GER). Little information is available on how anti-reflux surgery affects reflux mechanisms, especially TLESRs. We evaluated the effects of partial fundoplication (Belsey Mark IV) on reflux mechanisms. METHODS: Sixteen patients were prospectively studied before and after Belsey Mark-IV operation by endoscopy, 24-h esophageal pH-metry, and simultaneous recording of pH and lower esophageal sphincter (LES) characteristics by sleeve manometry. RESULTS: The operation was successful in 14 of 16 patients (87%). Fasting and postprandial reflux decreased significantly (P < 0.01) after the operation. Partial fundoplication significantly (P < 0.05) decreased the number of TLESRs per hour in the fasting and postprandial period from 3.2+/-0.4 and 5.6+/-0.5 to 1.7+/-0.3 and 2.8+/-0.4, respectively. The percentage of TLESRs associated with reflux also decreased significantly (P < 0.05). Basal LES pressure increased from 14.7+/-2.1 mmHg to 17.9+/-2.6 mmHg (not significant). CONCLUSIONS: Partial fundoplication controls GER through a reduction in the number of TLESRs and by decreasing the number of relaxations associated with reflux.

Adult

Effect of intragastric or intraduodenal administration of a polymeric diet on gallbladder motility, small-bowel transit time, and hormone release.

OBJECTIVE: During postpyloric tube feeding, GI intolerance is observed more frequently than during prepyloric feeding, possibly by evoking a stronger GI response. METHODS: We investigated the effect of intragastric and intraduodenal administration of a polymeric diet (125 kcal/h) on gallbladder motility (by ultrasonography), duodeno-cecal transit time (by lactulose H2 breath test), and GI hormone release (including cholecystokinin, pancreatic polypeptide, and gastrin). Six healthy subjects (two male, four female; mean age 22 yr, range 18-27 yr) were studied on two separate occasions in random order during 6 h of continuous administration of the diet through either the gastric or duodenal port of a two-lumen tube. RESULTS: Intraduodenal feeding resulted in a more rapid contraction of the gallbladder, from 32 +/- 4 to 23 +/- 4 cm3 at 10 min (p < 0.05), reaching a minimum of 6 +/- 1 cm3, in contrast to intragastric feeding (31 +/- 4 to 19 +/- 3 cm3 at 60 min, p < 0.05; minimum 14 +/- 1 cm3). The gallbladder remained contracted during the 6-h study period during both intraduodenal and intragastric feeding. Small-bowel transit time was significantly accelerated during intraduodenal compared with intragastric feeding (51 +/- 12 vs 81 +/- 9 min; p = 0.003). Plasma cholecystokinin secretion was significantly (p < 0.05) increased during intraduodenal compared with intragastric feeding (848 +/- 107 vs 279 +/- 89 pmol x L(-1) x 360 min). The same was true for pancreatic polypeptide secretion. However, gastrin release was significantly (p < 0.05) higher during intragastric feeding. CONCLUSIONS: Intraduodenal feeding elicited a stronger GI response than intragastric feeding, as demonstrated by accelerated small-bowel transit time, more rapid and stronger gallbladder contractions, and increased cholecystokinin and pancreatic polypeptide release. Gastrin release, on the other hand, was stronger during intragastric feeding.

Adolescent

Effect of medium- and long-chain triglycerides on lower esophageal sphincter pressure: role of CCK.

Fat meals are known to decrease lower esophageal sphincter (LES) pressure, possibly through postprandial CCK release. Dietary fat consists mainly of long-chain triglycerides (LCT), which potently stimulate CCK secretion. This effect contrasts with that of medium-chain triglycerides (MCT), which do not induce CCK release. We recorded LES pressure and gallbladder volume in six healthy subjects on five separate occasions during intraduodenal administration of 1) saline control, 2) LCT, 3) MCT, 4) LCT during intravenous infusion of the CCK receptor antagonist loxiglumide, and 5) MCT together with loxiglumide. LES pressure decreased significantly during administration of both LCT and MCT. Loxiglumide completely prevented the reduction in LES pressure during intraduodenal LCT, but not during intraduodenal MCT. Gallbladder volume decreased during LCT, but not during MCT. It is concluded that intraduodenal administration of equimolar amounts of both LCT and MCT significantly reduces LES pressure. The effect of LCT on LES pressure is mediated by CCK. The effect of MCT is not dependent on CCK, since MCT does not release CCK and loxiglumide does not prevent the MCT-induced reduction in LES pressure.

Adult

Do patients with systemic sclerosis have abnormal gallbladder function?

OBJECTIVE: To determine gallbladder motility in patients with systemic sclerosis. DESIGN: Case control study. SETTING: University hospital, out-patient department of rheumatology. PATIENTS: Ten patients with systemic sclerosis according to the criteria of the American Rheumatism Association with documented involvement of the gastrointestinal tract and 10 healthy controls matched for age, sex and body mass index. INTERVENTION: Cephalic vagal cholinergic simulation by modified sham feeding and hormonal stimulation by infusion of cholecystokinin. MEASUREMENTS: Gallbladder volume obtained by ultrasonography and determination of plasma cholecystokinin concentrations. RESULTS: Fasting gallbladder volumes were not significantly different between patients with systemic sclerosis and controls (19.6 +/- 1.9 cm3 and 23.3 +/- 2.9 cm3, respectively, mean plus or minus standard error of the mean). Neither were there significant differences in reduction of gallbladder volume in response to modified sham feeding (35 +/- 4% and 33 +/- 4%, respectively) nor during cholecystokinin infusion (56 +/- 4% and 60 +/- 6%, respectively). The increase in plasma cholecystokinin levels during infusion was not different in the two groups. CONCLUSION: Gallbladder motility in patients with systemic sclerosis is preserved in response to both cholinergic and hormonal stimulation, even when other gastrointestinal motor disturbances are present. These results suggest that patients with systemic sclerosis are not at increased risk for cholelithiasis because of gallbladder dysmotility.

Case-Control Studies

Gallbladder motility and cholecystokinin secretion during continuous enteral nutrition.

OBJECTIVES: During total parenteral nutrition, gallbladder motility is impaired, resulting in sludge and stone formation. Little is known about gallbladder motility during prolonged enteral nutrition. METHODS: We studied gallbladder motility during continuous enteral nutrition (CEN) in nine hospitalized patients with active inflammatory bowel disease. The patients received a polymeric diet (2000 kcal/24 h) by CEN through a nasogastric tube for a prolonged period. Gallbladder volumes were obtained daily by ultrasonography, starting from day 0 (before CEN) and on 7 consecutive days during CEN. At days 0, 1, 4, and 7, the gallbladder response to i.v. cholecystokinin (CCK-33; 0.5 Ivy Dog unit/kg/h) was studied. Plasma CCK levels were determined at regular intervals by radioimmunoassay. RESULTS: No significant differences were observed on day 0 between patients and a group of nine healthy control subjects in fasting gallbladder volumes (19.4 +/- 2.3 and 19.6 +/- 2.4 cm3, respectively) and gallbladder contraction during CCK infusion (56 +/- 14% and 69 +/- 7%, respectively). During CEN, from day 1 to day 7, mean gallbladder volume remained significantly (p < 0.05) reduced compared with fasting gallbladder volume, and mean plasma CCK levels remained significantly (p < 0.05) increased compared with fasting levels. Although gallbladder volume was significantly reduced during CEN, the gallbladder contractile response to CCK was not affected; at days 1, 4, and 7, gallbladder contraction was 36-57%. CONCLUSIONS: During CEN, 1) gallbladder volume is significantly reduced and plasma CCK levels are significantly increased, 2) these effects are sustained over time (7 days), and 3) the gallbladder remains responsive to exogenous CCK. These results indicate that gallbladder contractility and gallbladder responsiveness to CCK are preserved during prolonged CEN in patients with inflammatory bowel disease.

Adult

Effect of cholecystokinin on lower oesophageal sphincter pressure and transient lower oesophageal sphincter relaxations in humans.

The effect of cholecystokinin (CCK) on the lower oesophageal sphincter (LOS) pressure, frequency of transient LOS relaxations, and the number of reflux episodes was investigated in six healthy subjects. LOS pressure was recorded on four separate occasions during continuous intravenous infusion of either saline or CCK-33 in doses of 0.25, 0.5, or 1.0 Ivy Dog units per kg body weight per hour (IDU.kg-1.h-1) for 90 minutes. Plasma CCK concentrations did not change during saline infusion, but increased significantly from 2.5 (0.3) pmol/l to steady state levels of 4.0 (0.4) pmol/l, 6.1 (0.4) pmol/l, and 9.3 (0.9) pmol/l respectively starting from 30 minutes. LOS pressure did not change significantly during infusion of saline or of CCK-33 at doses of 0.25 or 0.5 IDU.kg-1.h-1. However, a significant (p < 0.05) reduction in LOS pressure to a minimum level of 12 (4) mm Hg at 30 minutes compared with basal level (18 (4) mm Hg) and compared with saline was observed during infusion of CCK-33 at a dose of 1.0 IDU.kg-1.h-1. In addition, oesophageal motility and pH were recorded simultaneously in these six subjects on two separate occasions one hour before (fasting) and three hours during administration of a gastric load (dextrose 5%, pH 3) combined with continuous intravenous infusion of saline or CCK-33 at a dose of 1.0 IDU,kg-1.h-1. Plasma CCK concentrations did not change during the gastric load combined with saline, but increased significantly to a steady state level of 10.8 (0.8) pmol/l during intravenous infusion of CCK. The number of transient LOS relaxations increased significantly in the first hour during administration of the gastric load compared with fasting levels, both during saline infusion (fasting: 1.7 (0.6)/h, 1st hour: 4.3 (1.2)/h) and during CCK infusion (fasting: 1.7 (0.5)/h, 1st hour: 3.8 (0.7)/h). In the second and third hours the number of transient LOS relaxations fell to fasting levels in both experiments. No significant differences were observed in the number and type of transient LOS relaxations, mechanism of gastro-oesophageal reflux, or duration of acid exposure between the two experiments. It is concluded that in healthy subjects infusion of CCK-33 in a dose of 1.0 IDU.kg-1.h-1 significantly reduces LOS pressure but does not affect the frequency of transient LOS relaxations or acid exposure time during a continuous liquid gastric load.

Adult

'The tropics in our bathroom': chronic diarrhoea after return from the tropics.

Interest in imported tropical diseases has increased with the rising number of travellers to the tropics. This is especially true in the case of tropical gastroenterologic disorders. The causative organisms of chronic diarrhoea are different from those causing acute diarrhoea. Bacteria are relatively unusual; parasites, e.g. Entamoeba histolytica or Giardia lamblia or an opportunistic parasitic infestation associated with an HIV infection are more likely. Furthermore, non-infectious causes, such as postinfective tropical malabsorption, lactase deficiency or coeliac disease have to be considered. Today, elderly people often undertake a journey to the tropics; in these cases the diarrhoea may be associated not only with an increased susceptibility to tropical bowel infections but also with causes previously present, such as diverticulosis, carcinoma or inflammatory bowel disease. The classification of chronic diarrhoea following a visit to the tropics is essentially the same as that for acute diarrhoea: diarrhoea with and without fever and with and without blood. In addition, malabsorption is an important feature of chronic diarrhoea.

Adult

Effect of equimolar amounts of long-chain triglycerides and medium-chain triglycerides on small-bowel transit time in humans.

BACKGROUND: The use of medium-chain triglycerides in diets is limited by the frequent occurrence of diarrhea or crampy abdominal pain. Because these symptoms may result from an accelerated transit time induced by medium-chain triglycerides, we investigated the effect of equimolar amounts of long-chain triglycerides and medium-chain triglycerides on small-bowel transit time in 10 healthy subjects. METHODS: Small-bowel transit time was measured by the lactulose hydrogen breath test after intraduodenal administration of lactulose. RESULTS: Intraduodenal administration of 20 mmol of long-chain triglycerides per hour for 90 minutes did not alter small-bowel transit time compared with control (77 +/- 11 minutes vs 77 +/- 10 minutes, respectively), whereas intraduodenal infusion of an equimolar dose of medium-chain triglycerides significantly accelerated small-bowel transit time (59 +/- 6 minutes) compared with long-chain triglycerides and control (p < .05). In six individuals, small-bowel transit time was shorter during the administration of medium-chain triglycerides compared with control, and three of these subjects experienced abdominal symptoms. Plasma cholecystokinin levels increased significantly (p < .05) during the administration of long-chain triglycerides, from 2.6 +/- 0.3 pmol/L to a maximum of 4.3 +/- 0.6 pmol/L. No significant alterations were observed in plasma cholecystokinin levels during administration of medium-chain triglycerides or in the control experiment. CONCLUSIONS: Although it significantly increases cholecystokinin secretion, the intraduodenal infusion of long-chain triglycerides does not affect small-bowel transit time, whereas the infusion of medium-chain triglycerides accelerates small-bowel transit time, independent of cholecystokinin.

Adult