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Biomedical subjects

G R Vantrappen

Publications and source records attributed to G R Vantrappen.

18 recordsLinked to original sources
PubMed1994

Whipple's disease: a histological, immunocytochemical, and electron microscopic study of the small intestinal epithelium.

At endoscopy, the duodenum in Whipple's disease frequently appears abnormal and some clinical features such as gastrointestinal blood loss and anaemia suggest epithelial damage. However, the intestinal epithelial cells themselves appear to be normal on light and electron microscopy. The aims of this study were to analyse in detail the cytological changes in epithelial cells over time and in response to therapy in biopsies obtained from 20 patients, to investigate the functional repercussion on digestive enzymes such as lactase, and to assess the expression by the epithelial cells of MHC antigens. Cytological changes were minimal at both the light- and the electron-microscopic level and MHC class I expression was preserved. However, changes indicative of functional deficits were demonstrated. Lactase and MHC class II expression were reduced or even absent. Antibiotic therapy resulted in normalization within 3-6 months. These findings are consistent with the clinical evolution and are of interest with regard to the importance of the immune response in aetiopathogenesis.

Adult↗
PubMed1993

Granulomatous gastritis: a morphological and diagnostic approach.

The final diagnosis of granulomatous gastritis is based on morphological findings and clinical and laboratory data. Detailed analysis of the morphological features of the granulomas together with associated mucosal changes could generate more information on aetiology and pathogenesis. Biopsies from 71 patients diagnosed as having granulomatous gastritis were reviewed. Thirty-seven of these patients (52%) had Crohn's disease. In 18 patients (25%) an isolated granulomatous gastritis was diagnosed. In seven patients (10%) the final diagnosis was a foreign body reaction. Of the remaining cases, four (7%) corresponded to tumour-associated granulomas and one case each of sarcoidosis (1%), Whipple's disease (1%) and vasculitis-associated disease (1%). Two cases (3%) were unclassifiable. The granulomas were mainly found in the antrum (64% antrum only, 11% antrum and corpus, 6% transitional mucosa corpus-antrum). Granulomas were usually small. This was particularly true for those found in patients with Crohn's disease. Multiple granulomas were observed in the sarcoidosis, the Whipple's disease and vasculitis-associated cases. A pattern of chronic gastritis with atrophy was present in 95% of the biopsies (68/71 patients). Helicobacter pylori was detected in 92% of the biopsies (64/71 patients).

Adolescent↗
PubMed1989

Mixed triglyceride breath test: a noninvasive test of pancreatic lipase activity in the duodenum.

A synthetic "mixed" triglyceride (1,3-distearoyl,2[13C]octanoyl glycerol), having a medium-chain fatty acid in the 2 position, was evaluated as a substrate for an exocrine pancreatic function test by comparing the 13CO2 breath excretion with the lipase output in the duodenum in 25 normal subjects, 29 patients with pancreatic disease, and 22 patients with steatorrhea of nonpancreatic origin. Excellent correlation was found in normal subjects and patients with pancreatic disease (r = 0.89) between lipase output in the duodenum and the 6-h cumulative 13CO2 excretion in breath, indicating that the mixed triglyceride breath test is an excellent noninvasive test of pancreatic lipase activity in the duodenum. As a test of exocrine pancreatic insufficiency, it has a sensitivity of 0.89 and a specificity of 0.81.

Adult↗
PubMed1987

Interdigestive fluctuations of plasma bile acid concentration: relation to interdigestive motility pattern.

In the fasting state, delivery of bile acids into the duodenum is related to the interdigestive migrating motor complex (MMC) and occurs during late phase 2. It has also been shown that in the dog this secretion is transported to the ileum, where bile acids are reabsorbed. We therefore studied plasma bile acid and motilin concentration in relation to small intestinal motility in human volunteers. Motor activity was recorded manometrically in 5 normal subjects after an overnight fast, until at least one full cycle of the migrating complex had been recorded. Pressures were measured in the antrum at 4 levels and in the upper small bowel at 3 levels. Blood samples were drawn every 10 min for radioimmunoassay of motilin and conjugated bile acids. Motilin levels fluctuated in accordance with the MMC cycle. Bile acid levels also fluctuated, but although fluctuations were poorly correlated to motilin levels, peaks of plasma bile acid occurred at or around the time of phase 3 activity. Also, the time lags between bile acid peaks, motilin peaks and phase 3 activity were almost identical, suggesting that peaks of plasma bile acid concentration are due to the arrival and absorption in the ileum of bile acids secreted during the preceding phase 2 and transported by the preceding phase 3. The poor correlation of plasma bile acid peaks with motilin peaks is probably due to the variability of transport and absorption of bile acids.

Adult↗
PubMed1983

Somatostatin and the interdigestive migrating motor complex in man.

The relationship between somatostatin and the interdigestive migrating motility complex (MMC) was determined in human volunteers. Motor activity was monitored manometrically by means of seven perfused catheters: four in the stomach, one in the duodenum, two in the jejunum. Blood samples were drawn every 10 min and radioimmunoassayed for motilin, pancreatic polypeptide and somatostatin. In four volunteers two activity fronts (AF) were recorded and somatostatin levels correlated to the manometric data. The start of an AF in the upper duodenum was accompanied by somatostatin peaks. Peak values, taken as the mean of the levels in the sample obtained after the start of an AF, the preceding sample and the next one, averaged 32 +/- 4 pM compared to 12 +/- 2 pM in the remaining period. In four volunteers somatostatin was infused in doses of 1.2, 2.4 and 4.8 pM/kg per min over three consecutive periods of 90 min, causing dose-dependent increments in plasma somatostatin levels of 7, 32 and 76 pM. In all volunteers and for all doses all gastric activity was completely inhibited. In the intestine phase 2 was abolished but phase 3 stimulated: during somatostatin infusion phase 3 occurred with an interval of 39 +/- 6 min. Motilin and PP levels were decreased. As the two lowest infusion doses caused increases in somatostatin levels that might be considered as physiological, somatostatin seems to have a physiological role in the regulation of the migrating motor complex. We propose that it facilitates the progressing of the activity front into the small intestine.

Adult↗
PubMed1982

Pancreatic polypeptide is not involved in the regulation of the migrating motor complex in man.

The role of pancreatic polypeptide (PP) and motilin in the regulation of the migrating motor complex (MMC) was studied in normal subjects. Both plasma motilin and PP levels changed cyclically in the fasted state and were highest in the late phase II period preceding the activity front in the duodenum. A continental breakfast invariably disrupted the MMC and induced a fed pattern of motility. After the meal plasma motilin levels decreased whereas PP levels rose significantly. Infusion of pure porcine motilin during the fasted state induced an activity front and a rise in plasma PP levels. Infusion of bovine PP in doses producing plasma PP levels above the postprandial values neither induced an activity front nor prevented its occurrence. During PP infusion, however, plasma motilin levels were low, although the activity front was not inhibited. PP seems to have no clear role in the regulation of the motor component of the MMC of man. The role of motilin in the production of the activity front of the MMC is discussed.

Duodenum↗
PubMed1981

A mixed-triglyceride breath test for intraluminal fat digestive activity.

A new test of intraluminal fat digestive activity is proposed for which a mixed triglyceride, 1,3-dioleyl-2-14C-decanoyl glycerol, was used. 29 normal subjects, 14 patients with proven chronic pancreatitis, 10 pancreatectomy, 12 villus atrophy and 8 bile acid-deficient patients were studied. The mean 14CO2 excretion in breath, expressed as the 10th-hour cumulative percentage of the administered dose, was 68.3% in the normal subjects, and only 32.9% in patients with pancreatic disease. There was almost no overlap between the normal subjects and the patients with proven organic disease. The test also allowed the detection of functional pancreatic insufficiency, due to impaired pancreatic stimulation in case of gluten enteropathy and severe malabsorption.

Adult↗
PubMed1981

Simple extraction method and radioimmunoassay for somatostatin in human plasma.

Interference by human plasma proteins in the radioimmunological determination of somatostatin was eliminated by subjecting plasma samples to acid--ethanol precipitation. The assay was performed on the lyophilized supernate from 300 microliters of human plasma, with reagents that are commercially available. Sensitivity was 2.6 pg, corresponding to 8.7 ng/L of plasma. The intra-assay CV was 8%; the inter-assay CV was 12% for a low (30 ng/L) and 15% for a high (100 ng/L) standard. The mean analytical recovery of exogenous somatostatin from plasma was 95%, and the standard synthetic cyclic somatostatin showed parallel dilution curves with extracted plasma samples. Neither gastrin HG-17 and HG-34, pentagastrin, secretin, glucagon, vasoactive intestinal polypeptide, substance P, nor pancreatic polypeptide interfered in the assay system. Mean immunoreactive somatostatin in 20 normal fasting subjects was 31.5 (SD 15.6) ng/L and ranged from 14 to 67 ng/L.

Cross Reactions↗
PubMed1979

The secretory component of the interdigestive migrating motor complex in man.

Intraduodenal pH, bicarbonate and amylase secretion, and gastric acid and pepsin output were studied in relation to the migrating motor complex in man. The occurrence of a motor complex in the duodenum was preceded by an increase in gastric acid and pepsin output and followed by a peak in bicarbonate and amylase secretion. It is concluded that the interdigestive phase in man is characterized by periodic activity complexes comprising both motor and secretory components. These observations may have important implications for the interpretation of currently used functional tests of gastrointestinal secretion.

Amylases↗
PubMed1978

Radioimmunoassay for urinary lysozyme in human serum from leukemic patients.

We present a radioimmunoassay for lysozyme in human serum, based upon human lysozyme isolated from the urine of leukemic patients and antiserum prepared against this lysozyme in the goat. In the separation step, a second antibody is used. By properly adjusting the concentrations of unlabeled and 125I-labeled lysozyme and of the antibodies, maximal precision (SD, 0.04 mg/litre) was obtained in the range 0.00 to 2.00 mg/litre. In 20 normal volunteers the lysozyme concentration was 4.6 +/- 0.8 mg/litre (mean +/- SD), in 13 patients with monocytic leukemia 34.4 +/- 8.6 mg/litre. Correlation with lysoplate determinations was excellent in leukemic sera (r = 0.97) but was poor in normal sera (r = 0.35), possibly owing to the existence of isoenzymes.

Humans↗
PubMed1977

Factors influencing lysozyme determinations by the lysoplate method.

Some factors influencing the lysoplate method have been investigated. The influences of pH, ionic strength and temperature of the gel medium can be explained by considering the influence of these factors upon the diffusion rate rather than upon the enzymatic properties of lysozyme. Salts and proteins present in a sample probably affect the results in a similar way. Although the method has a variation coefficient around 10% and thus an acceptable precision, its accuracy is variable and doubtful. The method could be clinically interesting, by discriminating lysozyme isoenzymes, or by indirectly detecting proteins associated with some disease states.

Biological Assay↗
PubMed1977

Choice of monitoring isotope in double label radioimmunoassays with nonimmunological separation techniques.

We discuss the suitability of some radioactive isotopes as volume markers in radioimmunoassays, from a radiochemical point of view. For three eligible isotopes (22Na, 60Co, and 75Se) we studied the concentration of the marker in the precipitate formed in the separation phase of radioimmunoassays. For all those kinds of separations tested (charcoal, ammonium sulfate, polyethylene glycol, and ethanol), binding or coprecipitation was virtually absent or negligible with 22Na but 75Se was strongly concentrated in the precipitate. Concentration of 60Co occurred only with charcoal and ethanol precipitation. Because heavy metals tend to bind to serum proteins, we conclude that of all radioactive isotopes commercially available only 22Na should be used in radioimmunoassays with nonimmunological separation methods.

Charcoal↗
PubMed1976

Purification and partial characterization of lysozyme from mouse small intestine.

Lysozyme was isolated from the small intestine of mice by combined ion-exchange and molecular sieve chromatography. This lysozyme differs from that isolated from the urine of mice with monocytoma in amino acid composition, and migration rate in cellulose acetate electrophoresis. As intestinal lysozyme originates at least in part from the Paneth cell, our results point towards the existence of isozymes of lysozymes in mice.

Amino Acids↗