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J Borovicka

Publications and source records attributed to J Borovicka.

28 records · Page 2Linked to original sources
PubMed1996

Role of antrum in regulation of pancreaticobiliary secretion in humans.

Little is known about the role of the gastric phase in the postprandial pancreaticobiliary response. We evaluated the effect of antral distension on pancreatic, biliary, and gastric secretions and on the release of cholecystokinin (CCK), gastrin, and pancreatic polypeptide in five healthy volunteers. Studies were performed using a duodenal tube with an inflatable balloon in the antrum and a separate gastric tube. Outputs were compared with responses to a maximal CCK stimulus (caerulein), and the role of cholinergic mechanisms was investigated using atropine. Graded antral distension by 50-, 200-, and 350-ml balloon volumes and constant antral distension by 350 ml elicited a marked stimulation of pancreaticobiliary secretions. Mean lipase outputs amounted to 52-60%, and mean bilirubin outputs reached 14-22% of maximal. Atropine completely abolished pancreaticobiliary responses to antral distension. Antral distension did not affect bicarbonate and gastric secretions. Plasma pancreatic polypeptide levels increased markedly during antral distension, and this effect was completely suppressed by atropine. There were no changes in circulating gastrin and CCK. These data demonstrate that antral distension with already small volumes of 50 ml elicits a hitherto unknown potent stimulatory effect, indicating a major role of the antrum in the postprandial pancreaticobiliary response in humans, which is mediated by cholinergic mechanisms.

Adult↗
PubMed1996

Measurement of proximal and distal gastric motility with magnetic resonance imaging.

The precise motor mechanisms associated with gastric emptying of nutrient liquids are unclear, in part because of difficulties in measuring the motility from the proximal and distal stomach simultaneously. We have now examined proximal and distal gastric motility, using a novel magnetic resonance imaging (MRI) technique. In seven healthy volunteers (4 males, 3 females; 27-37 yr), gastric emptying and motility were determined on two occasions after ingestion of 500 ml 10% and 25% dextrose labeled with 1 mM gadolinium tetraazacyclododecane tetraacetic acid, using a 1.5-tesla Philips Gyroscan ACS II scanner. Gastric emptying was determined every 15 min with a series of transaxial scans. After each series of transaxial scans, 120 coronal scans, 1.2 s apart, were performed through the antrum and proximal stomach. For each coronal slice the diameters of the proximal stomach and the antrum were measured to determine the number of contractions per minute and depth (%basal diameter). Gastric emptying (half-emptying time) was faster after ingestion of 10% compared with 25% dextrose (49 +/- 15 vs. 118 +/- 37 min; P < 0.01). After both meals, the diameter of the proximal stomach remained relatively constant, whereas there were marked fluctuations in the diameter of the antrum. Mean (+/- SD) frequency (2.8 +/- 0.6 vs. 2.0 +/- 0.8/min; P < 0.001) and depth (40 +/- 17% vs. 34 +/- 16%; P < 0.04) of antral contractions were higher after 10% dextrose compared with 25% dextrose. Rapid MRI techniques allow simultaneous measurement of both gastric emptying and motor function of different gastric regions. The increase in the frequency and depth of distal gastric contractions during ingestion of 10% compared with 25% dextrose supports the concept that the antrum contributes to the regulation of gastric emptying of nutrient liquids.

Adult↗
PubMed1996

Role of cholecystokinin as a regulator of solid and liquid gastric emptying in humans.

The role of endogenous cholecystokinin (CCK) in the regulation of gastric emptying remains controversial. We therefore studied the effect of the CCK-A receptor antagonist loxiglumide on gastric emptying of a high-caloric solid-liquid meal in humans. Gastric emptying was assessed in eight volunteers using intravenous loxiglumide or placebo in a randomized double-blind order. Subjects were studied by a dual-headed gamma camera after ingestion of a pancake (570 kcal) labeled with 99mTc-sulfur colloid and 500 ml 10% glucose containing 111In-diethylenetriamine pentaacetic acid. Plasma CCK was measured by a specific radioimmunoassay. Loxiglumide markedly accelerated gastric emptying of both phases of the meal. The lag period was shortened by 26% (P < 0.03); the area under the emptying curve and half-emptying time of solid emptying were lowered by 19 and 24% (P < 0.02) and of liquid emptying by 18 and 24% (P < 0.04), respectively. Plasma CCK levels were higher during infusion of loxiglumide compared with placebo (P < 0.02). These data demonstrate that post-prandially released CCK is a major regulator of gastric emptying of physiological meals containing both solid and liquid components.

Adult↗
PubMed1996

Evaluation of delayed gastric emptying in diabetic patients with autonomic neuropathy by a new magnetic resonance imaging technique and radio-opaque markers.

OBJECTIVE: Our objective was to validate a new noninvasive magnetic resonance imaging (MRI) technique for diagnosis of delayed gastric emptying by using radio-opaque markers (ROMs) in diabetic patients with and without cardiovascular autonomic (CAN) and peripheral sensomotoric neuropathy (PSN). RESEARCH DESIGN AND METHODS: Fifteen diabetic outpatients were recruited, eight with CAN and PSN (group A, age 28-61 years, mean diabetes duration 27 years) and seven without CAN (group B, age 28-60 years, mean diabetes duration 16 years). Gastric emptying and motility were assessed with ROMs and MRI in random order. After an overnight fast either a test meal (451 kcal) containing a capsule with 10 ROMs is eaten and a supine plain abdominal X ray is taken after 6 h or 500 ml intralipid 10% (550 kcal) is swallowed for the MRI study, using a 1.5 Tesla Gyroscan ACS II (Philips, Eindohoven, The Netherlands). Computer-assisted segmentation of images was used to measure gastric emptying (T1/2, min) over 125 min, contraction frequency (F, min-1), mean contraction amplitude (CA, % basal), and velocity (V, cm/s). Blood glucose was kept constant at 5.0-8.0 mmol/l. RESULTS: In group A, 6.1 +/- 1.36 ROMs (mean +/- SE) were retained in the stomach after 6 h and 0 ROM in group B, indicating a significant delay of gastric emptying in patients with CAN. The MRI study revealed a significantly longer gastric emptying (P < 0.005) in group A (T1/2 = 124 +/- 10 min) as compared with group B (T1/2 = 85 +/- 18 min). There was no difference in F, CA, and V between the two groups: F 2.9 +/- 0.07 and 2.7 +/- 0.1 (min-1), CA 26.8 +/- 1.2 and 29.6 +/- 1.6 (% basal), V 0.43 +/- 0.02 and 0.40 +/- 0.02 (cm/s), respectively. CONCLUSIONS: MRI offers the possibility of visualizing and examining exactly the mechanisms responsible for gastric emptying and is characterized by a high specificity but a lower sensitivity as compared with ROMs, which proved to be an ideal screening test for diagnosis of gastroparesis in clinical practice.

Adult↗
PubMed1995

Cerulein-induced changes in plasma amino acid concentrations are not a valid test for pancreatic insufficiency.

OBJECTIVES: There is controversy about the cholecystokinin (CCK)-induced decrease of plasma amino acids for the diagnosis of pancreatic insufficiency in that it is unclear whether the conflicting results are due to different degrees of stimulation by CCK. We have therefore evaluated the amino acid consumption test by examining the dose-response relation among increasing doses of cerulein and plasma amino acids compared with the release of pancreatic polypeptide in six healthy volunteers and six patients with severe pancreatic insufficiency proven by a pathological para-aminobenzoic acid test. METHODS: Stepwise increasing doses of cerulein (10-80 pmol/kg/h) were given i.v., each for 60 min with a secretin background (1 CU/kg/h). In the volunteer group, an additional experiment with infusion of placebo (saline 0.9%) was performed. RESULTS: CCK-induced amino acid changes were small in volunteers (maximum decrease: 8.4 +/- 0.9%; mean +/- SEM), tended to be more pronounced in patients (maximum decrease: 13.8 +/- 2.8%; NS), and did not permit a distinction among volunteers and patients. There was no dose-response relationship between CCK and plasma amino acids in either group. In contrast, pancreatic polypeptide levels increased markedly and dose-dependently in volunteers and patients and tended to be lower in patients with pancreatic insufficiency. CONCLUSIONS: The decrease of plasma amino acid levels in response to cerulein does not reflect pancreatic function and does not permit the diagnosis of pancreatic insufficiency.

Adult↗
PubMed1994

Gastric motility measurement by MRI.

The motor mechanisms associated with gastric emptying of nutrient liquids are unclear. Gastric emptying and motility were determined in seven healthy volunteers using an MRI technique following ingestion of 500 ml of (1) 10% and (2) 25% dextrose labeled with 1 mM Gd-DOTA. Emptying was determined with transaxial scans and motility during fast coronal scans 1.2 sec apart. Emptying was slower after ingestion of 25% dextrose. Following both meals, proximal gastric diameter remained relatively constant, while antral contractile frequency and depth varied markedly. These variations were greater after 10% dextrose. These studies suggest that antral motility changes contribute to slowing of gastric emptying by nutrient meals.

Animals↗
PubMed1994

Measurement of gastric emptying and gastric motility by magnetic resonance imaging (MRI).

Hitherto it has been impossible to measure noninvasively gastric emptying and motility from multiple regions of the stomach in humans. We describe the development of a novel methodology to achieve this using magnetic resonance imaging (MRI). Initial validation studies performed in five healthy volunteers demonstrated similar gastric emptying curves and secretion rates after ingestion of 10% dextrose labeled with [Gd]DOTA, assessed by MRI ([Gd]DOTA as meal marker) and a simultaneous double-indicator technique. Comparison between MRI and scintigraphy in five patients also gave similar results. Application of newer MRI technology allowing a series of coronal scans 1.2 sec apart permitted quantification of wall motion in the proximal and distal stomach in seven healthy volunteers. These results indicate that MRI provides new insights into the mechanisms responsible for both normal and disordered emptying.

Contrast Media↗
PubMed1993

[Motility disorders and assessment methods of the esophagus].

Esophageal diseases frequently cause symptoms such as heartburn, epigastric pain and dysphagia. This article discusses the indications, techniques and limitations of currently available diagnostic procedures. Investigation of symptoms should proceed in a logical stepwise manner, beginning with endoscopy to exclude esophagitis or neoplasia. Symptoms due to acid reflux can be identified by 24h esophageal pH-metry to document a temporal association between symptoms and episodes of esophageal acidification. Stationary or ambulatory manometric recording of esophageal pressures can be used to diagnose esophageal motor disorders such as achalasia, nutcracker esophagus, diffuse esophageal spasm, or dysfunction of the upper or lower esophageal sphincter. Combined 24 h pH-manometry should be used to test the temporal association between pain, reflux, or abnormal motility in patients with non-cardiac chest pain. Video-fluoroscopy is the most appropriate technique to diagnose swallowing disorders. Pulmonary aspiration of gastro-esophageal reflux can be documented with scintigraphy.

Deglutition Disorders↗