Publications by authors named "Ecknauer R"

The effect of a high osmotic solution on active and passive sugar permeation was investigated in 19 healthy volunteers. The reduced rate of active sugar absorption (3-O-MG and xylose) out of a high osmotic solution was interpreted as a consequence of an impaired emptying of the stomach. The increased passive permeation of intact disaccharides applied in hyperosmolar solution demonstrates an increased gastrointestinal permeability.

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In the nonanesthetized rat, the jejunal permeability to four simultaneously administered molecules, mannitol, phenol red, inulin and PVP, was measured by analyzing blood, serum, urine and duodenal fluid for these compounds. Of the molecules which had entered the body, approximately 50% were found in the urine, another 50% in the extracellular space and only about 1% were excreted into the duodenal juice. The intracellular content of the molecules is not accounted for in these numbers.

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Antrectomy reduced the levels of circulating gastrin but did not change jejunal morphology. In vitro and in vivo absorption as well as the activity of some brush border enzymes were increased. The observed alterations are discussed on the basis of antrectomy-induced alterations in the release of gastrointestinal hormones, gastric and pancreatic secretion and gastric emptying.

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Age-related changes in the gut were investigated in male gnotobiotic rats, living in a controlled and constant environment until death. Parameters of the regenerative compartment of the jejunum and ileum were the cell production rate (measured by a stathmokinetic technique), the number of crypts, and the crypt:villus ratio. Parameters of the functional compartment were the average surface area of the villi, height and broadness of villi, etc.

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The present review tries to coordinate anatomical barriers and the biochemical and immunological events controlling and even preventing the entry of substances from the external environment into the extra- and intra-cellular space of the body. A selection of diseases with disturbance of the "barrier function" is included.

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Feeding an elemental diet (Vivonex) to rats over 9 days causes a decrease in the rate of cell renewal and a reduction in villus size in both the jejunum and ileum, as compared with rats fed regular chow. The addition of bulk to elemental diet cannot prevent the reduction in villous size, but it can cause a small increase in the rate of cell renewal, which is still much lower than that in chow-fed rats. The serum gastrin level of rats fed the elemental diet is about one-third of the level found in chow-fed rats, and it is not changed by the addition of bulk.

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After an oral load of 10 g polyethylene glycol, its concentration in the urine was measured by gas chromatography. The coefficient of variation of the imprecision between run was about 11%. The urinary excretion was 25% of the administered dose with a coefficient of variation of the interindividual variation 26% and the intraindividual variation between 13% and 29%.

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The tritiated muscarinic cholinergic antagonist quinuclidinyl benzilate, [3H]QNB, was used as a direct probe for the detection and characterization of muscarinic cholinergic receptors associated with the particulate fraction of isolated and purified rat gastric muscosal parietal cells. Specific binding is saturable (Bmax = 55 fmol/mg protein, KD = 0.78 nM), shows a single population of binding sites, and has appropriate pharmacological specificity.

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A modified Roux-en-y repositioning of rat proximal small intestine resulted in a gut segment (A) exposed only to digestive secretions, but not to food and a gut segment (B) exposed to food, stomach juice and by reflux only to digestive secretions, and a third segment (C) exposed to both, food and digestive secretions. The changes in segment A were qualitatively very similar to those occurring after removal of luminal nutrition (intravenous feeding, self-emptying blind loop, and Thiry Vella loop). These findings support the hypothesis that the presence of luminal nutrition is a major factor regulating mucosal mass and enzyme activity in rat proximal small intestine.

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Cytostatica not only suppress proliferation in tumor cells but it also checks proliferation in small intestinal epithelium. The consequence is cell reduction and damage resulting in a diminished function. Because of the high reserve capacity of the small intestinal epithelium, clinical signs of diminished function are mostly seen after repeated high doses or one extremely high doses of Cytostatica.

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Starvation for 48 hrs reduced the activity of sucrase referred to unit length in rat proximal small intestine by approximately 30%, irrespective of whe her mucosal scrapings, isolated villus epithelial cells or brush border membranes were investigated. Sucrase activity referred to unit weight, unit protein or to unit DNA of intestinal epithelium did not change.

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Starvation overnight and starvation for 48 h reduced the weight and the protein content of mucosal scrapings, but only minimally reduced the DNA content of the mucosal scrapings. The activity of sucrase and maltase was reduced by both periods of starvation. The activity of lactase and of acid and alkaline phosphatase, however, was less subject to starvation.

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1. Complete mechanical obstruction of the distal small intestine was produced in gnotobiotic rats. 72 h after the operation small intestinal morphology and epithelial cell renewal were investigated proximal and distal to the site of obstruction.

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At an average of 32 days after a modified Roux-en-y repositioning of rat small intestine, the mucosal mass, mucosal composition, in vivo absorption of galactose and the activity of maltase, sucrase and alkaline phosphatase were measured. In the gut segment with digestive secretions but without food (A) the only change was a decrease of sucrase activity which occurred most probably at the cellular level. In the gut segment with food and gastric juice and a reflux of digestive secretions (B) complex changes took place.

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Widely used methods in diagnostical and experimental gastroenterology like measuring the protein-and DNA-content and the activity of alkaline phosphatase and sucrase of intestinal mucosa were adapted to a microliter system and partly automatized. With "artificial" control material a system for statistical quality control was established. Lastly the results on up to three years experience with this control system were presented showing an imprecision within run below 5% and an in-imprecision between run below 8% in all methods.

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A modified Roux-en-Y repositioning of rat small intestine was performed so that the proximal segment of bowel (A) received only bile and pancreastic secretions, the second (B) received food direct from the stomach, and these two segments drained into a third (C). Four to five weeks after operation, cell production was assessed by injection of vincristine into operated, sham-operated and unoperated rats, and counts of blocked metaphases were made on isolated microdissected crypts. Villus height, crypt depth, and the number of crypts per villus (crypt/villus ratio) were also measured.

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Six and twelve hours after a single i.p. dose of cyclophosphamide (100 mg/kg body weight) the activity of different "brush border enzymes" (maltase, sucrase lactase, alkaline phosphatase, gamma-glutamyl transferase) and of a lysosomal enzyme (acid phosphatase) did not change.

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After a single dose of cyclophosphamide (100 mg/kg) cell proliferation in the jejunum of the rat decreased within the first 24 h and returned to the initial level after 48 h. Under the influence of cyclophosphamide, an increased cell loss in germfree rats could be observed. Villus height and villus cell count tended to decrease.

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The protein determination method according to Lowry and the DNA test according to Schneider were adapted to a microliter scale thus rendering feasible serial determinations with an adequate degree of accuracy. The criteria for reliability (precision within the series and day after day) are sufficient.

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