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J J Rumessen

Publications and source records attributed to J J Rumessen.

At least 37 records · Page 2Linked to original sources
PubMed1993

[Dimethicone in lactulose-induced dyspepsia. Effect on H2 production and symptoms].

The results of studies of the effect of simethicone on abdominal gas-related symptoms have been contradictory. In a randomized, double-blind, cross-over study, ten healthy volunteers were given 30 g lactulose and 600 mg simethicone or placebo. End-expiratory breath samples were collected and analyzed for H2, and gastrointestinal symptoms registered. There were no differences in biochemical parameters or symptom score between simethicone and placebo. In contrast to previous studies, we used a sufficiently large dose of lactulose to produce gastrointestinal symptoms, a higher dose of simethicone and placebo tablets containing the same additives as the simethicone tablets. There was no demonstrable effect of simethicone on symptoms or intestinal gas production caused by carbohydrate malabsorption.

Adolescent↗
PubMed1993

Immunohistochemical localization of a gap junction protein (connexin43) in the muscularis externa of murine, canine, and human intestine.

Electron-microscopic studies have revealed a heterogeneous distribution of gap junctions in the muscularis externa of mammalian intestines. This heterogeneity is observed at four different levels: among species; between small and large intestines; between longitudinal and circular muscle layers; and between subdivisions of the circular muscle layer. We correlated results obtained with two immunomethods, using an antibody to the known gap-junctional protein (connexin43) with ultrastructural findings, and further evaluated the respective sensitivity of these two approaches. For comparative reasons we also included the vascular smooth muscle of coronary arteries into our study. Two versions of the immunotechnique (peroxidase-antiperoxidase and fluorescence methods) were applied to frozen sections of murine, canine, and human small and large intestines, as well as to pig coronary artery. In the small intestine of all three species a very strong reactivity marked the outer main division of the circular muscle layer, while the longitudinal muscle layer as well as the inner thin division of the circular muscle layer were negative. In murine and human colon both muscle layers were negative, while in canine colon the border layer between the circular muscle and the submucosa reacted strongly, and scattered activity was found in the portion of the circular muscle layer (one tenth of its thickness) closest to the submucosa. The remainder of the circular muscle layer and the entire longitudinal muscle layer were negative in the canine colon. In the coronary artery we could not confirm the positive, specific labeling reported by other investigators (l.c.).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Ultrastructure of interstitial cells of Cajal in circular muscle of human small intestine.

BACKGROUND: Interstitial cells of Cajal (ICC) may be important regulatory cells in gut muscle layers. This study examined ICC within the circular muscle of human small intestine. METHODS: Surgically resected, uninvolved intestine was studied by light microscopy and electron microscopy. RESULTS: Muscle lamellae were separated by main septa in continuity with submucosa. Smooth muscle cells ran radially in the septa. Two types of ICC were distinguished. One ICC type had abundant intermediate filaments and smooth cisternae and a discontinuous basal lamina. This ICC type was present in the septa and in the outer third of the circular lamellae. The other ICC type had a complete basal lamina and conspicuous caveolae. This ICC type was observed only in the inner third of the circular lamellae. Both ICC types were close to nerves, but only the latter type formed gap junctions with one another and with muscle cells. Junctions between the two ICC types were not observed. CONCLUSIONS: The arrangement suggests that ICC and radially oriented muscle cells participate in electrical and mechanical coordination of the circular muscle layer of human small intestine.

Adult↗
PubMed1993

Light- and electron microscopical studies of interstitial cells of Cajal and muscle cells at the submucosal border of human colon.

BACKGROUND: It has been suggested that interstitial cells of Cajal (ICC) at the submucosal border of the colonic circular muscle are pacemaker cells. We studied smooth muscle cells and ICC at the submucosal surface of the circular muscle layer of the normal human colon. EXPERIMENTAL DESIGN: Resected, unaffected specimens from human colon were studied by light microscopy and transmission electron microscopy. RESULTS: Throughout the colon, the inner fourth of each circular-muscle lamella was covered with a layer of 2 to 15 muscle cells (ICMC) with a smaller diameter, more perinuclear organelles, and a greater glycogen content than the outer circular muscle cells. ICMC were interconnected by adherens junctions and close appositions. Small bundles of ICMC were present in the submucosa. ICC were identified in all regions of the colon (ascendens, transversum, and sigmoideum) at the submucosal border, in deeper parts of the submucosa in close contact with smooth muscle bundles as well as in the circular muscle and main septa. ICC had a continuous basal lamina, caveolae, dense bands, thin and intermediate filaments, dense bodies and a well-developed smooth endoplasmic reticulum. Mitochondria and granular endoplasmic reticulum were very abundant. Lipid droplets and glycogen granules were frequent. Thick (myosin) filaments were absent. Close contacts to nerves and gap junctions to other ICC or smooth muscle cells were exceptional. Fibroblast-like cells in the submucosa were rich in granular endoplasmic reticulum and intermediate filaments. They had few dense bands and caveolae. Mitochondria, smooth cisternae and glycogen granules were sparse, cytoplasmic dense bodies and a continuous basal lamina were lacking. Fibroblast-like cells were associated closely with collagen bundles and they had no close contacts with nerves, ICC or muscle cells. CONCLUSIONS: Throughout the normal human colon, submucosal ICC and ICMC are identified and distinguished from other cell types present. Their organization and cytology differ from that of other animal species. The ultrastructure of ICC and ICMC is compatible with important regulatory functions on the circular muscle in the entire human colon.

Aged↗
PubMed1992

Characterization of macrophage-like cells in the external layers of human small and large intestine.

In the external layers of human small and large intestine macrophage-like cells were characterized by immunohistochemical, histochemical and electron-microscopical methods. Using immunohistochemistry and a number of monoclonal antibodies, the presence and distribution of phenotypic subpopulations of macrophages were evaluated. In all locations macrophage-like cells were identified with antibody EBM11, which recognizes CD68 antigen, C3bi which recognizes CD11b, and partly with an antibody which recognizes protein 150,95 (CD11c). Macrophage-like cells in the external muscle layer were HLA-DR-positive (expressing the MHC class-II antigen), in contrast to macrophage-like cells in the subserosa and submucosa. Macrophage-like cells in the external muscle layer were mostly acid phosphatase-negative, and at the electron-microscopic level they were found to have features of macrophages: primary lysosomes, coated vesicles and pits. However, very few secondary lysosomes were present. Birbeck granules were not observed. It is concluded that in the external muscle layer of human small and large intestine numerous macrophages of a special type are present. It is discussed whether this cell type plays a role in gastrointestinal motility and/or has an immunological function.

Acid Phosphatase↗
PubMed1992

Ultrastructure of interstitial cells of Cajal associated with deep muscular plexus of human small intestine.

Evidence showing that interstitial cells of Cajal have important regulatory functions in the gut musculature is accumulating. In the current study, the ultrastructure of the deep muscular plexus and associated interstial cells of Cajal in human small intestine were studied to provide a reference for identification and further physiological or pathological studies. The deep muscular plexus was sandwiched between a thin inner layer of smooth muscle (one to five cells thick) and the bulk of the circular muscle. Interstitial cells of Cajal in this region very much resembled smooth muscle cells (with a continuous basal lamina, caveolae, intermediate filaments, dense bodies, dense bands, and a well-developed subsurface smooth endoplasmic reticulum), but the arrangement of organelles was clearly different, and cisternae of granular endoplasmic reticulum were abundant. Interstitial cells of Cajal were distinguished from fibroblasts or macrophages in the region. They ramified in the inner zone of the outer division of circular muscle, penetrated the inner-most circular layer, and were also found at the submucosal border. They were in close, synapselike contact with nerve terminals of the deep muscular plexus, and only few gap junctions with other interstitial cells of Cajal or with the musculature were observed. Compared with interstitial cells of Cajal from other mammals, those associated with the deep muscular plexus in the human small intestine more closely resemble smooth muscle cells, and their organization appears more diffuse; however, the ultrastructure and organization of interstitial cells of Cajal is compatible with modulatory actions on the circular muscle also in humans.

Adult↗
PubMed1992

Assimilation of wheat starch in patients with chronic pancreatitis. Positive effect of enzyme replacement.

Pancreatic insufficiency due to chronic pancreatitis may lead to symptomatic malabsorption of both starch and fat. The absorption capacity of wheat starch has not been studied previously in patients with chronic pancreatitis, although this carbohydrate is a quantitatively important component of the Western diet. We studied the absorption of wheat starch and the effect of pancreatic enzyme substitution in seven patients with chronic pancreatitis and steathorrea. The malabsorption was determined from hydrogen breath tests with lactulose standards as reference. Without enzyme substitution, wheat starch (50 g) was absorbed to a lesser extent than in healthy controls (p less than 0.05). The mouth-to-cecum transit time was prolonged and correlated positively to the fat excretion before substitution with pancreatic enzymes (sigma = 1). The enzyme substitution increased the absorption of wheat starch to values seen in healthy controls (p less than 0.05) and reduced the mouth-to-cecum transit time by 19.8%.

Adult↗
PubMed1992

Absorption of wheat starch in patients resected for left-sided colonic cancer.

Bacterial fermentation of carbohydrate in the colon, producing short-chain fatty acids (SCFA)--and especially butyrate--has been shown possibly to impede cell proliferation and regulate cell differentiation of colonocytes. In patients with diverticular disease or benign polyps in the colon a hyperabsorption of potato starch in the small intestine has been found. We have investigated the absorption of wheat starch in 15 patients radically resected for cancer in the descending or sigmoid colon, and the results were compared with those of 15 healthy controls. The starch malabsorption was quantified by the hydrogen breath test. The patients malabsorbed 2-14 g (median, 8 g) of 100 g wheat starch ingested, and the control group malabsorbed 3-11 g (median, 6 g) (P greater than 0.1). Mouth-to-cecum transit time for wheat starch and lactulose and the hydrogen production capacity after the lactulose standards were also similar in patients and controls. The results do not support the theory that hyperabsorption of starch is characteristic of patients with malignant disease in the large intestine.

Adult↗
PubMed1992

Fructose and related food carbohydrates. Sources, intake, absorption, and clinical implications.

It is possible to point out subjects consuming considerable quantities of fructose and sorbitol, and the intake seems to be increasing both from added and natural sources. Studies of the absorption of fructose in animals are inconsistent, and the mechanisms of fructose uptake seem to vary in accordance with the species. In most species fructose absorption takes place by a specific carrier (facilitated transport), but it may be active in the rat. In vitro studies of human intestine are very scarce; there is no evidence of active intestinal fructose transport in the human intestine. By means of hydrogen breath tests, a very low absorption capacity for fructose given as the free monosaccharide has been found in humans. Fructose given as sucrose or in equimolar combinations with glucose is well absorbed, and only fructose in excess of glucose is malabsorbed. On this basis it is hypothesized that two different uptake mechanisms for fructose are present in the human intestine. One of these may be a disaccharidase-related uptake system. Sorbitol ingestion may aggravate malabsorption of fructose given as the monosaccharide; it is not known whether a specific mechanism is involved. In children and adults with functional bowel distress the absorption capacities for fructose may not differ from those of healthy individuals, but malabsorption of fructose and/or sorbitol may be the cause of or aggravate abdominal symptoms. Fructose polymers (fructans) are also subject to increasing nutritional interest. Fructans are not absorbed in the small intestine but are strongly fermented in the large bowel. Fructans may be of potential benefit for large-bowel function and blood glucose regulation.

Breath Tests↗
PubMed1992

Hydrogen and methane breath tests for evaluation of resistant carbohydrates.

This review considers in detail the background, principles, techniques, limitations and advantages of the hydrogen and methane breath tests. Resistant food carbohydrates, defined as dietary carbohydrates partly or totally escaping small intestinal assimilation, are fermented in the human colon. This results in production of H2, CH4 and volatile fatty acids. Increased colonic H2 production is a sensitive index of increased carbohydrate fermentation, and a rather constant fraction of the colonic H2 production is excreted by the lungs. It is therefore possible to assess mouth-to-caecum transit times as well as to estimate absorption capacities for several types of resistant carbohydrates by means of H2 breath tests. A prerequisite for correct interpretation is that procedures for determination of H2 concentrations and for breath sampling and storage are carefully validated and standardized. Due to the large interindividual variations of hydrogen excretion, unabsorbable standards should be used. The intraindividual variations of H2 production/excretion and differences in fermentability of different carbohydrate substrates only allow for semiquantitative estimates of malabsorbed amounts of some carbohydrates. Methane breath tests may supplement the information gained from hydrogen measurements, but further evaluations are needed. The hydrogen breath technique is rapid, simple and non-invasive as well as non-radioactive. It may be carried out in a large number of intact individuals under physiological circumstances, and it may be used for studies in children and for field studies. Compared to classical tolerance tests the hydrogen breath test is more sensitive. It is concluded that the hydrogen breath test is a useful tool for investigations of dietary carbohydrates.

Breath Tests↗
PubMed1991

Prostaglandin H synthase immunoreactivity in human gut. An immunohistochemical study.

Prostaglandins exhibit a variety of actions on intestinal smooth muscle depending upon the type, dose and muscle layer studied. As the cellular origin of prostaglandin H (PGH) synthase has not been established with certainty in the human gut wall, we studied the localization of PGH synthase in the human duodenum, jejunum, ileum and colon by immunohistochemistry. PGH synthase immunoreactivity appeared to be similar in all segments of the intestine. Most smooth muscle cells seemed to contain PGH synthase; however, the reaction in the lamina muscularis mucosae was much stronger than in the longitudinal and circular muscle layers. Endothelial cells in capillaries and larger vessels showed a positive reaction. In addition, unidentified cells in subserosa, at the level of Auerbach's plexus and in the submucosa were stained. We concluded that the smooth muscle cells of the human gut has a rather large capacity for PGH synthesis and the present results may provide a basis for a better understanding of both normal physiological functions as well as intestinal disease states involving disorders of prostaglandin synthesis.

Aged↗
PubMed1991

Effect of simethicone on lactulose-induced H2 production and gastrointestinal symptoms.

The results of studies of the effect of simethicone on abdominal gas-related symptoms have been contradictory. In a randomized, double-blind cross-over study, 10 healthy volunteers were given 30 g lactulose and 600 mg simethicone or placebo. End-expiratory breath samples were collected and analyzed for H2 and gastrointestinal symptoms registered. There were no differences in biochemical parameters or symptom score between simethicone and placebo. In contrast to previous studies, we used a sufficiently large dose of lactulose to produce gastrointestinal symptoms, a higher dose of simethicone and placebo tablets containing the same additives as the simethicone tablets. There was no demonstrable effect of simethicone on symptoms or intestinal gas production caused by carbohydrate malabsorption.

Adult↗
PubMed1991

Interstitial cells of Cajal in human small intestine. Ultrastructural identification and organization between the main smooth muscle layers.

Previous morphological and electrophysiological studies have supported the hypothesis that interstitial cells of Cajal have important regulatory (pacemaker) functions in the gut. In the current study, interstitial cells of Cajal associated with Auerbach's plexus in human small intestine were studied. Freshly resected intestine was examined by light and electron microscopy. The interstitial cells of Cajal resembled modified smooth muscle cells. They had caveolae and dense bodies, an incomplete basal lamina, a very well-developed smooth endoplasmic reticulum, and abundant intermediate (10 nm) filaments. Myosin filaments were not seen. Fibroblast-like cells were distinguished by their lack of caveolae and dense bodies, the relative scarcity of smooth cisternae and intermediate filaments, and the abundant granular endoplasmic reticulum. Interstitial cells of Cajal were arranged in networks of bundles containing processes of two to seven cells with fibroblastlike cells interspersed in the bundles. The bundles were innervated by nerve elements of Auerbach's plexus and extended into both layers of smooth muscle, between muscle cells, and into septa. The bundles were closely associated with elastin fibers. The organization shown in this study strongly supports the concept of interstitial cells of Cajal as important regulatory cells also in the human small intestine. The characteristic cytology and organization of interstitial cells of Cajal may provide a basis for future morphological, electrophysiological, and pathological studies of these cells in human small intestine.

Adult↗
PubMed1990

Fructans of Jerusalem artichokes: intestinal transport, absorption, fermentation, and influence on blood glucose, insulin, and C-peptide responses in healthy subjects.

Fructans are naturally occurring plant oligosaccharides with sweetening properties. Fructans (FAs) isolated from Jerusalem artichokes (Helianthus tuberosus) were studied with respect to intestinal handling and influence on blood glucose (BG), insulin, and C-peptide responses in eight healthy subjects. The responses were compared with those for fructose ingestion. The effect of FAs added to a wheat-starch meal was also studied. Standardized breath-hydrogen excretion indicated that FAs were completely malabsorbed and, after a 20-g dose, traces of FA were detected in 24-h urine collections in one subject only. Orocecal transit times were longer for FAs than for lactulose and fructose. The BG and insulin increments were very low after FA ingestion, lower than after fructose ingestion, whereas hydrogen production was much higher. Areas under BG curves tended to be smaller when 10 g FA was added to a 50-g wheat-starch meal, but there was no apparent interference with starch absorption.

Absorption↗
PubMed1990

Interval sampling of end-expiratory hydrogen (H2) concentrations to quantify carbohydrate malabsorption by means of lactulose standards.

Lactulose H2 breath tests are widely used for quantifying carbohydrate malabsorption, but the validity of the commonly used technique (interval sampling of H2 concentrations) has not been systematically investigated. In eight healthy adults we studied the reproducibility of the technique and the accuracy with which 5 g and 20 g doses of lactulose could be calculated from the H2 excretion after their ingestion by means of a 10 g lactulose standard. The influence of different lengths of the test period, different definitions of the baseline and the significance of standard meals and peak H2 concentrations was also studied. Regardless of baseline definition, estimates of malabsorption were most precise, if areas under the H2 concentration v time curves for four hours or more from the start of the excess H2 excretion were used. The median deviations from the expected values were 20-30% (5-60%, interquartile range). This corresponded to the deviation in reproducibility of the standard dose. We suggest that individual estimates of carbohydrate malabsorption by means of H2 breath tests should be interpreted with caution if tests of reproducibility are not incorporated. Both areas under curves and peak H2 concentrations seem valid for comparison of groups.

Adult↗