Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Three-dimensional structure and cell kinetics at different sites of rat intestinal remnants during the early adaptive response to resection (1982)
    Springer
    Research in experimental medicine 181 (1982), S. 77-94 
    Details
    ISSN: 1433-8580
    Keywords: Intestinal resection ; Three-dimensional structure ; Cell kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In this study the early phase of the morphological adaptation of rat ileum after a proximal resection of 60% has been studied using microdissection and cell labelling techniques. Resected rats and sham-operated controls were killed 2, 4, 6, 10 and 12 days after surgery. Intraperitoneal injections of3H-thymidine were carried out 24 or 12 h prior to sacrifice. In the latter groups mitotic arrest was achieved by vincristine. A stereo-microscope was used to measure and calculate the following parameters: intestinal diameter; villus: height, width, breadth at base and apex, surface, enterocytes per 100µm length, cell pool, number of villi and absorptive surface per mm2 serosal area; crypt: length, enteroblasts per 100µm length and per column, cell columns and mitoses per crypt, cell pool, crypts, and mitoses per unit serosal area; cell kinetics: migration rate, villus transit time. To test the influence of treatments, postoperative time course and the location of the intestinal segment and their possible interactions, factorial analyses of variance were carried out on the parameters investigated. The main findings, demonstrated for the first time, were: 1. An increase in the villus surface which was achieved by proportional enlargement of villus geometry; 2. This increase in the villus surface led to an enlarged absorptive surface per unit serosal area; 3. A reduction of villus transit time of the individual enterocyte; 4. A most pronounced magnitude of adaptative response in the proximal remnants which was gradually diminished in aboral direction, and 5. A sequential course of adaptative response of the various crypt parameters investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01852185
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The adaptive response of disaccharidase activities at different sites along the villus epithelium after proximal intestinal resection in the rat (1983)
    Springer
    Research in experimental medicine 182 (1983), S. 203-213 
    Details
    ISSN: 1433-8580
    Keywords: Disaccharidases ; Section biochemistry ; Mucosal hyperplasia ; Intestinal adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The “in situ” kinetic constants (app. $$\bar K_m$$ and $$\bar V_{max}$$ ) of brush border neutralα-glucosidase (EC 3.2.1.20) and lactase/β-glucosidase (EC 3.2.1.21) were determined 4, 6 (onlyα-glucosidase), and 12 days after 60% proximal intestinal resection in rat ileum at the villus base and the transition zone between middle and upper villus third by use of a quantitative biochemical analysis of enzymes in tissue sections (section biochemistry). Sham-operated rats served as controls, and the kinetic data (means per rat, time and villus position) were compared (n=4 animals in each experimental group) first by an overall factorial analysis of variance and thereafter in detail using nonparametric test procedures. Both enzyme activities exhibited a differential response: No changes of lactase/β-glucosidase kinetics, but a significant decrease in both $$\bar V_{max}$$ - and $$\bar K_m$$ -values of neutralα-glucosidase, which was already fully expressed on day 4 after resection and confined to the apical villus region still implying a basoapical increase of $$\bar V_{max}$$ and thus maintaining the normal activity gradient on a lower level. In conclusion, a complex pattern of enzymatic adaptation to proximal intestinal resection ensues in the hyperplastic ileal mucosa which cannot be explained simply in terms of the hypothesis of cellular immaturity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01851709
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Structural and functional correlations in the hypertrophic mucosa of intestinal remnants following resection in rats (1982)
    Springer
    Research in experimental medicine 181 (1982), S. 95-104 
    Details
    ISSN: 1433-8580
    Keywords: Influx kinetics ; Intestinal resection ; Microdissection ; Structure/function correlations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 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 ofl-phenylalanine andα-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 the mucosal: serosal surface ratio 1.9 times larger than normal. The influx of phenylalanine andα-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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01852186
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    “In situ”-measurements of protein contents in the brush border region along rat jejunal villi and their correlations with four enzyme activities (1981)
    Springer
    Histochemistry and cell biology 72 (1981), S. 467-479 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In order to quantify the amount of protein in the small intestinal brush border region at different villus sites, cryostat sections of adult rat jejunum were stained with Naphthol Yellow S, Dinitrofluorobenzene and Coomassie Brilliant Blue and the dye deposits were evaluated cytophotometrically. Judged by the absorbance spectra in the tissue sections and the increase in absorbance as a function of the optical pathway (section thickness), Naphthol Yellow S proved to be the most suitable quantitative protein stain. By continuously measuring the absorbance of this dye at λ 440 nm rectangular to the villus in the longitudinal axis of the enterocytes, a peak was registered in the brush border region which clearly could be differentiated from the apical cytoplasm. The amount of protein in the brush border region was determined at six different positions equally distributed along the villus. In parallel four brush border enzymes (neutral α-and β-glucosidase, unspecific alkaline phosphatase and dipeptidylpeptidase IV) were quantified by the same measuring technique in the Vmax-range of their substrate hydrolysis at equivalent villus positions. Their activities were correlated to the amount of protein. The absorbance data both for protein and for enzyme activities were significantly influenced by the villus position. They revealed an increasing gradient from the basal to the apical villus. In an additional analysis of the breadth of the dye deposits at the different measuring positions on the villus, it was shown that this parameter also ran parallel with the absorbance values.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00501789
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Kinetic characterization of unspecific alkaline phosphatase at different villus sites of rat jejunum (1980)
    Springer
    Histochemistry and cell biology 69 (1980), S. 189-202 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A quantitative histochemical method to determine the apparent Km and V max values of rat intestinal unspecific alkaline phosphatase at different sites of the villi is described. Naphthol-As-Bi-phosphate (0.025–1.5 mM) is employed as substrate and Fast Blue B as coupling reagent, and the resulting azo-dye in the brush border membrane has an absorbance maximum at λ550 nm. The ratio between the absorbance at λ550 and λ500 nm is constant as calculated from automatically recorded spectra at different intense dye deposits. Its absorbance is a linear function of incubation time up to 3 min and thickness of the slices up to 10 μm both with medium (0.5 mM) and high (1.5 mM) substrate concentrations. Using the histochemical assay under comparable conditions in test tube experiments with homogenates of intestinal mucosa an app. Km of 0.26±0.081 mM (weighted regression analysis) and 0.28–0.084 mM (direct linear plotting) is determined, demonstrating an affinity to the histochemical substrate, which is about 10 times higher than for p-Nitro-phenyl-phosphate with the purified enzyme. The results obtained by scanning the total dye deposits along jejunal villi show considerable differences in enzymatic activity between single villi and an increase from the villus base up to the transition between medium and apical villus third. As well in the apical region as at the villus base saturation curves are obtained by determining the relationship between the absorbance and the substrate concentration under standard conditions (slice thickness 10 μm, incubation time 3 min, 37°C, pH 8.3). Calculated by weighted regression analysis and direct linear plotting from the absorbance data of six female rats the medium app. kinetic data ±SD from the jejunal villi read as follows. Apical: Km=0.81±0.438 mM, V max=3.99±1.217 absorbance units (A) and Km=0.87±0.428 mM, V max=4.02±1.191 A, respectively. Basal: Km=0.82±0.261 mM, V max=3.26±0.719 A and Km=0.77±0.184 mM, V max=3.04±0.518 AU, respectively. As demonstrated by factorial analysis of variance only V max is influenced by the villus position.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00533136
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Quantification of α-glucosidases along the villus of the small intestine in man (1980)
    Springer
    Histochemistry and cell biology 67 (1980), S. 85-97 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A method is introduced which enables the two-dimensional detection and analysis of absorbancy-values from continous dye-deposites with rather low data storage capacity. Applied to histochemical reactions this method is used for kinetic analysis of enzymes along the intestinal villus. Its main part consists of two programs for two dimensional scanning, i.e. along the villus and at right angle from the lumen across the brush-border membran to the apical cytoplasma. Two further programs serve as prerequisites: the automatical detection of mean values and the description of absorbancy spectra in the tissue section. The measurements are carried out with a MPVII Leitz in connection with a Hewlett Packard 9815 A calculator. The study of α-glucosidases of the human small intestine is taken to demonstrate the value of the method. It is shown that a similar Vmax-gradient along the villus can be demonstrated as by microchemical methods. Thus this method enables the description of the kinetic properties of a distinct enzymatic activity in preserved tissue sections on the cellular level and the possible alterations of V max and K m in context to the morphological pattern.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00490091
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...