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Biomedical subjects

R Ecknauer

Publications and source records attributed to R Ecknauer.

At least 19 recordsLinked to original sources
PubMed1985

[Effect of osmolality on the gastrointestinal permeation of various carbohydrates in healthy persons].

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. Intubation studies suppose increased disaccharide absorption out of hyperosmolar solution in the stomach, i.e. high osmolar solutions increase gastric mucosal permeability.

3-O-Methylglucose↗
PubMed1983

Effect of antrectomy on small intestinal structure and function in the rat.

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.

Animals↗
PubMed1983

An experimental model for measuring intestinal permeability.

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. The rate of permeation decreased with increasing molecular weight of the substances. EDTA (25 mmol/l) and deoxycholate (5 mmol/l) increased the jejunal permeability for these molecules but not for mannitol. The alterations in mucosal cell turnover and morphology induced by hydroxyurea did not change jejunal permeability for mannitol and phenol red at any time. 24 and 48 h following hydroxyurea, jejunal permeability for inulin and PVP was decreased.

Animals↗
PubMed1982

Intestinal morphology and cell production rate in aging rats.

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. Age did not change the size of individual villi or crypts or the cell production rate. The number of crypts and, to the same extent, the number of villi increased with age, indicating a continuation of mucosal growth up to an age of 2 yr.

Aging↗
PubMed1982

[The barrier-function of the gastrointestinal (author's transl)].

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.

Biological Transport↗
PubMed1981

Elimination of low molecular weight polyethylene glycol 400 in the urine following an oral load, as a measure of intestinal permeability.

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%.

Humans↗
PubMed1981

Effect of dietary bulk on small intestinal morphology and cell renewal in the rat.

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.

Animals↗
PubMed1980

Isolated parietal cells: [3H]QNB binding to putative cholinergic receptors.

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. Nanomolar concentrations of muscarinic cholinergic antagonists, such as atropine and scopolamine, inhibit [3H]QNB binding by 50%, whereas micromolar concentrations are needed for agonists, such as acetylcholine, oxotremorine, and carbamylcholine. Binding is also stereoselective as shown by the more than 1,000-fold difference in inhibitory potencies of the stereoisomers of benzetimide. Noncholinergic agents, including pentagastrin, histamine, and the H2-receptor antagonists cimetidine and metiamide, have little or no effect on [3H]QNB binding at concentrations of 100 microM. These data support the existence of specific parietal cell muscarinic cholinergic receptors with which the secretagogue acetylcholine may directly interact to initiate gastric acid secretion.

Animals↗
PubMed1978

[Cytostatica and small intestine (author's transl)].

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. Although there is abundant information on the effect of Cytostatica on the small intestinal epithelium (cell turnover, morphology, digestive enzymes and absorption) there are other areas that are as urgent for the interested clinician to work on: 1. Would it be possible to coincide the dose and dosage rate with the cell cycles to reduce the chance of damage to small intestinal epithelium? 2. Which role has the luminal content when there is damage from Cytostatica? Is it possible to concentrate on changing the luminal contents (antibiotics, "elemental diet", cultivate desirable microflora, etc.) Therefore diminishing the damage from Cytostatica? 3. How would Cytostatica influence the barrier function on the intestinal wall? Should the patient on Cytostatica therapy receive special protection against intestinal infection? 4. Does Cytostatica affect the biotransformation in the small intestinal epithelium, especially when taken orally? How important is this biotransformation in small intestinal epithelium damaged by Cytostatica therapy? 5. What factors determine the regeneration of the small intestinal epithelium after Cytostatica damage?

Animals↗
PubMed1978

Analysis of the effects of food and of digestive secretions on the small intestine of the rat: III. Mucosal mass, activity of brush border enzymes, and in vivo absorption of galactose, sodium, and potassium.

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. The changes in the luminal environment in segment B caused an increase in mucosal mass (in the proximal half only), an increase in sucrase activity which paralleled the increase in mucosal mass, and no change in activity of alkaline phosphatase which in fact was a decrease in activity ;at the cellular level'. Later on the net absorption of sodium and potassium was improved and the disappearance of galactose was unchanged when referred to unit length of small intestine.In segment C there was a small increase in mucosal mass, an increase in activity only for alkaline phosphatase, and an improvement of the net absorption of sodium without changes in the disappearance of galactose. These changes were compatible with a more proximal promotion of a distal gut segment.

Alkaline Phosphatase↗
PubMed1978

Effect of starvation on small intestinal enzyme activity in germ-free rats.

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. There were striking differences in the response to starvation between the proximal, mid and distal third of the small intestine. The importance of the proper reference system was discussed.

Acid Phosphatase↗
PubMed1978

Starvation and sucrose activity in small intestinal mucosa. An evaluation of different tissue preparations and reference systems.

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.

Animals↗
PubMed1977

Acute distal intestinal obstruction in gnotobiotic rats. Intestinal morphology and cell renewal.

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. 2. Proximal to the site of obstruction there were minor changes in villus height, base length and in villus cell number, a large increase in depth and diameter of the crypts and an approximately threefold increase in cell renewal. 3. Distal to the site of obstruction there were no differences between the intestines of rats with obstruction and controls. 4. The apparent lack of secretion by the goblet cells and the reduced number of intraepithelial leucocytes suggest that the barrier function of the small intestine is impaired in obstruction.

Animals↗
PubMed1977

An experimental model for studies on the effects of food and digestive secretions on the digestive-absorptive capacity of rat small intestine.

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. An increase in mucosal mass was not accompanied by an increase in galactose absorption. There was a high increase of sucrase activity, a moderate increase of maltase activity and a tendency of the alkaline phosphatase activity to decrease. The changes (increase in mucosal mass and total enzyme activity, but no changes in activity at the cellular level) in the segment exposed to both digestive secretions and food (C) were compatible with a more proximal promotion of a distal gut segment.

Alkaline Phosphatase↗
PubMed1977

Measurement of enzyme activity and substrates in intestinal mucosa. Evaluation of a system for quality control in clinical and experimental gastroenterology.

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.

Alkaline Phosphatase↗