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H Menge

Publications and source records attributed to H Menge.

At least 73 records · Page 4Linked to original sources
PubMed1982

Structural and functional correlations in the hypertrophic mucosa of intestinal remnants following resection in rats.

Microdissection techniques were applied to determine the absolute increase in villus size and absorptive surface in the mucosa of rat intestinal remnants 3 weeks after 60% proximal resection. Adjacent tissues were used to evaluate the operational kinetic parameters describing the influx of L-phenylalanine and alpha-methyl-D-glucoside into intestinal rings. The villi of ileal remnants were enlarged significantly in all dimensions; the mean surface area of the villus was 2.5 times, and mucosal:serosal surface ratio 1.9 times larger than normal. The influx of phenylalanine and alpha-methyl-glucoside into the mucosa of ileal remnants was reduced, but the change could not be ascribed to an attenuation of one specific kinetic parameter. Using the microdissection data to transform the Vmax-values to a mucosal area basis, we could demonstrate that the Vmax for both substrates was smaller than normal. The results may derive from changes in the maturity of the cell population in intestinal remnants.

Animals↗
PubMed1982

Adaptative response of alpha- and beta-glucosidase kinetics along the villi of rat self-filling jejunal blind loops.

Four and 12 days after the construction of self-filling jejunal blind loops in the rat, the apparent Km- and Vmax-values of lactase/beta-glucosidase and neutral alpha-glucosidase were determined by in-situ quantitative enzyme histochemistry, and changes in the villus-crypt architecture of the mucosa were examined by microdissection. The results were compared with corresponding data from sham-operated controls. The kinetics data were obtained from the base and the transition zone between medium and apical villus third by the use of a microdensitometric technique. The apparent Vmax of lactase/beta-glucosidase is significantly smaller than in the control rats at both measuring sites of the villi and even decreases from day 4 to day 12. The apparent Vmax of neural alpha-glucosidase is not affected, and thus the same increase in enzyme activity along the villi as in the controls is observed. The apparent Km of this enzyme, however, is already significantly increased on day 4 at both villus positions in the blind loops. A pronounced increase in villus surface area is detected in the blind loops as a result of an increase in crypt cell proliferation. The results indicate that enzymatic adaptation in the self-filling blind loops of rat jejunum exhibits different patterns for brush border alpha- and beta-glucosidases and is at least in part accomplished independently of the pronounced mucosal transformation occurring in this experimental condition.

Animals↗
PubMed1982

Kinetic properties of neutral alpha-glucosidase in the atrophic mucosa of self-emptying blind loops of rat jejunum: a microdensitometric study at two different villus sites.

The in situ kinetic constants of neutral alpha- glucosidase were determined in the atrophic jejunal mucosa of self-emptying blind loops and in corresponding jejunal segments of control rats, using a quantitative histochemical technique. The apparent maximum velosity (Vmax) and km values were calculated from absorbance measurements of an azo dye-deposit formed in the brush border membrane at the villus base and at the transition zone between the middle and upper one-third of the villus. In the controls a significant increase of apparent Vmax and substrate affinity (decrease of apparent Km) was obtained, corresponding to enterocyte maturation along the villi. The mucosal atrophy in self-emptying blind loops was accompanied by a significant decrease of apparent Vmax of neutral alpha-glucosidase at both representative villus sites, but the substrate affinity was increased at both sites. The results indicate that alpha-glucosidase activity was reduced when measured at the cellular level of two representative villus sites in the atrophic jejunal mucosa, possibly due to the absence of substrate-effected enzyme induction. The decrease on hydrolytic enzyme activity was not matched by a compensatory increase in substrate affinity.

Animals↗
PubMed1981

Intestinal obstruction in germ-free dogs.

Mechanical occlusions were created in the intestines of four germ-free dogs. At the time of the operation, a control loop of mid-intestine was perfused in vivo and then excised for examinations in vitro, which included the determination of the equilibrium uptake of phenylalanine and of beta-methyl-glucoside, the influx kinetics of phenylalanine and morphometric analysis of the mucosa by microdissection and stereological techniques. Seven days after establishment of the occlusion the abdomen was reopened, and loops above and below the occlusion were perfused, and then excised for the same tests in vitro. Unlike occluded loops of conventional dogs, the intestine of the germ-free animal above the occlusion does not secrete water and electrolytes into the lumen. Its transport properties in vitro do not differ from those of the control loop, and the morphometric analyses reveal only slight changes in villus structure. The loop below the obstruction undergoes marked atrophy, as has been observed in conventional dogs. The results suggest that the copious secretion that occurs above an intestinal obstruction in normal animals is due to the presence of an abundant bacterial population in the obstruction fluid.

Animals↗
PubMed1980

Structural and functional correlations in the atrophic mucosa of self-emptying blind loops of rat jejunum.

Marked atrophy of the mucosa develops in self-emptying blind loops of rat jejunum. The application of microdissection techniques revealed a 74% reduction in the mucosal surface area of the blind loops, 3 weeks after their creation. Kinetic studies of the influx of L-phenylalanine and beta-methyl-D-glucoside into rings of blind loops showed that the Km for both mechanisms was unchanged, but that there was a small reduction in the Vmax for both substrates, when expressed in terms of unit weight of incubated tissue; this attained 31% for phenylalanine and 12% for beta-methyl-glucoside. When the kinetic data were combined with the morphometric results, it could be shown that the Vmax for both substrates, when expressed per unit area of mucosal surface, was more than twice as large in the blind loop epithelium as in normal tissue. Such findings indicate either that the individual cells of the blind loop epithelium possess more transport sites than normal, or that there is a greater proportion of absorptive cells within the blind loop mucosa.

Animals↗
PubMed1979

Structural and functional alterations in the mucosa of self-filling intestinal blind loops in rats.

1. Self-filling blind loops of jejunum were constructed in three groups of rats; in the first, blind loops were created without further manipulation; in the second the bile was diverted permanently into the lower ileum below the blind loop, whereas in a third neomycin was added to the drinking water throughout the experiment. Two weeks after the creation of the blind loops, they were used for structural and functional studies. 2. Morphometric and microdissection techniques demonstrated that the surface area of the individual villi of the mucosa of 'ordinary' blind loops had increased fourfold in comparison with corresponding control jejunum, whereas the increase was only twofold in rats with bile diversion or in the series treated with neomycin. There were proportional increases in crypt length and mitotoic activity of the crypts in all three series, which suggest that the alterations in the mucosa were due to hyperplasia in both villus and crypt compartments. 3. Sucrase, succinate dehydrogenase, alkaline phosphatase and non-specific esterase activities, determined biochemically or histochemically, were reduced in the mucosae of all blind loops, though the changes were most pronounced in the 'ordinary' blind loops. The accumulation of L-phenylalanine by mucosal slices in vitro was depressed, although the decrease was less marked in the series treated with neomycin. 4. These results suggest that both bacteria and deconjugated bile acids play a role in the development of the hyperplastic changes of the blind-loop mucosa, but that another factor might also be involved: as a possible candidate, stasis of the intestinal contents was considered. 5. To test this hypothesis, loops of rat colon were transposed into the jejunum. Above the transposed loop, the jejunal mucosa developed hyperplasia of both villus and crypt compartments, with a reduction in its ability to accumulate L-phenylalanine. It is argued that these changes, probably caused by stasis of the intestinal contents, are triggered off by the dilatation of the gut, which may also be implicated in the mucosal alterations in blind loops.

Alkaline Phosphatase↗
PubMed1979

Quantitative study of mucosal structure, enzyme activities and phenylalanine accumulation in jejunal biopsies of patients with early and late onset diabetes.

A study of the three-dimensional structure of the upper jejunal mucosa in diabetics has been carried out. The structural findings were related to 14C-L-phenylalanine uptake in vitro, sucrase activity in mucosal homogenates, and the enzyme content of the absorptive cells as measured cytophotometrically. A low grade mucosal transformation of the sprue-type was found, which was associated with decreased sucrase activity, and with no reduction in phenylalanine accumulation. On the other hand the specific activities of alkaline phosphatase, non-specific esterase, and succinic dehydrogenase in the surface cells remained unchanged.

Adult↗
PubMed1979

[The effect of theophyllin on small intestinal structure and function of the diabetic rat (author's transl)].

In order to obtain some information about the role of cAMP in the regulation of cell turnover of the intestinal mucosa it was interesting to investigate whether chronic pharmacologically induced changes in the cellular cAMP levels could cause alterations in mucosal growth in the case of a well defined animal modell, involving increased cell proliferation rate, such as chronic experimental diabetes mellitus of the rat. Since it has been suggested that cAMP levels on the one hand are low in cell division and increased cAMP levels on the other hand inhibit cell division, the aim of the study was to induce a suppression of the cell proliferation rate in the intestinal mucosa by chronic theophyllin application, a well known PDE-inhibitor. The following results could be obtained: Chronic theophyllin application induces a hyperplastic alteration of the small intestinal mucosa of the rat, which is similar to that observed in diabetes mellitus. In diabetic animals theophyllin causes a further increase in hyperplasia. The morphological alterations of the intestinal mucosa are more pronounced than the functional changes. In experimental diabetes mellitus the radioimmunologically determined cAMP level in the intestinal mucosa is rather low. Chronic theophyllin application alone or in combination with experimental diabetes mellitus was unable to increase the cAMP-level continuously. This could be a result of an adaptive change of the cAMP regulating enzyme system. Therefore theophyllin induced mucosal alterations are probably due to systemic effects of this drug.

Animals↗
PubMed1978

The relationship between the functional and structural alterations in the rat small intestine following proximal resection of varying extents.

The functional and structural characteristics of the ileal remnant of rat intestine were examined four weeks after 45%, 70% or 95% proximal resection. The increase in villus height in the ileal remnant had alfread reached its maximum after a resection of 45%, whereas a further increment in the length of the crypts occurred after 70% resection. There was an increase in the number of enterocytes per unit length of villus and a rise in the DNA content per unit weight of mucosal scrapings, which testifies to the development of mucosal hyperplasia in this situation. The specific activities of sucrase, measured biochemically, and of nonspecific esterase, determined histochemically, were reduced in proportion to the extent of the resection. Similarly, the uptakes of L-phenylalanine and of beta-methyl-D-glucoside by intestinal rings in vitro were progressively diminished in the ileal remnant. There was an increase in the rate of disappearance of glucose from a perfused loop in vivo, when expressed in terms of unit intestinal length. Galactose absorption remained unchanged, but when expressed in terms of unit dry tissue, was significantly reduced, in agreement with the diminished transport of both amino-acids and monosaccharides in vitro.

Animals↗
PubMed1978

Sugar transport by brush border membrane vesicles isolated from human small intestine.

Uptake of D- and L-glucose, and fructose by purified brush border membrane vesicles isolated from human small intestine was studied using a rapid filtration technique. The uptake of D-glucose by the vesicles was osmotically sensitive and represented transport into an intravesicular space and not binding to the membranes. Transport of both, D- and L-glucose was inhibited by phlorizin. Uptake of D-fructose into the brush border vesicles was not stimulated by sodium. In the presence of a sodium gradient D-glucose was taken up 5 times faster than L-glucose. The amount of D-glucose transported into the vesicles in the presence of a sodium gradient was transiently higher than the amount of D-glucose taken up at equilibrium (over-shoot). D-Glucose transport was stimulated only by a sodium gradient; other monovalent cations had no effect. In the presence of a sodium gradient D-glucose transport was increased by the nearly impermeable anion sulfate as compared with uptake of D-glucose in the presence of a sodium chloride gradient. This indicates an influence of the electrical membrane potential on the sodium coupled non-electrolyte transport.

Biological Transport↗
PubMed1978

Glucose transport by brush-border membrane vesicles after proximal resection or ileo-jejunal transposition in the rat.

1. The functional properties of the ileal mucosa following jejunal resection or interposition in the jejunum were studied with the help of membrane vesicles. 2. Despite the development of functional and morphological features in the mucosa which are more generally associated with the jejunum than with the ileum, examination of brush-border vesicles derived from ileal and jejunal enterocytes from resected or transposed intestines reveals that the functional characteristics of apical membranes isolated from the different regions of the intestine are maintained after these surgical manoeuvres. Vesicles from control ileum develop an 'overshoot' uptake of glucose that is 3-4 times smaller than that of jejunal vesicles, a difference that is still observed in membranes prepared from mucosa of ileal loops following proximal resection or interposition in the jejunum.

Animals↗
PubMed1978

Lack of effect of bile in pathogenesis of secretion in mechanical small bowel obstruction.

In dogs, the principal lesion in the ileal mucosa above a mechanical obstruction is the induction of a secretory state in which there is a net loss of water and electrolytes into the intestinal lumen. The role of stagnated bile as a possible agent provoking this secretion was explored by ligating the common bile duct and diverting the bile by means of an anastomosis between the gall bladder and the ileum distal to the obstruction. 7 days after creation of an obstruction with bile diversion, the functional and morphological changes in the obstructed loop were almost identical to those occurring in animals with obstructions without bile diversion. The secretory response above the obstruction continued unabated, with levels of cAMP in the secreting mucosae lower than in control tissues. These results suggest: (a) that the secretion in the obstructed intestine is not influenced by the presence of bile, and (b) that this secretion may not be secondary to an increase in mucosal cAMP levels.

Animals↗
PubMed1978

[Functional tests in small bowel diseases (author's transl)].

D-xylose-, Schilling-test, and fecal fat analysis are still the most important functional tests in small bowel diseases despite rapid progress in enterology. The segmental intestinal perfusion technique can be considered to be the most appropriate method at the moment to measure absorptive or secretory capacity of defined gut segments. Under well-defined conditions the tissue accumulation technique with fresh small bowel biopsy specimens may offer valuable results on absorptive capacity of the gut tissue in specialized laboratories.

Fats↗