ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
    5′-Nucleotidase in spinal meningeal compartments in the rat (1992)
    Springer
    Histochemistry and cell biology 98 (1992), S. 135-139 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of 5′-nucleotidase (5′-Nu) is reported in spinal meninges of the rat on the basis of an immunohistochemical and enzyme histochemical investigation. Strong immunoreactivity was found in the arachnoid membrane and in the sheaths of the spinal roots as well as in septa subdividing the roots. Also the superficial layer of the ligamentum denticulatum showed enzyme staining. No immunoreactivity could be detected in the pia mater or along the spinal nerve roots outside the subarachnoid space. Within the arachnoid mater the immunoreactivity was concentrated in the basal zone of the arachnoid membrane, thus appearing as a narrow fluorescent band near the border of the dura. An accentuation of immunoreactivity could be observed in areas where small dural blood vessels approach the subarachnoid space. It is well known that adenine nucleotides released from neural and glial cells of the central nervous system finally reach the cerebrospinal fluid. We presume that 5′-Nu in the arachnoid membrane and spinal root sheaths is responsible for the conversion of adenine nucleotides into adenosine and that this conversion is associated with the reabsorption process of cerebrospinal fluid which most probably also takes place in spinal meninges. Adenosine, the product of 5′-nucleotidase, could play a role in the reabsorption process by its vasodilatatory effect on dural and epidural vessels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00717005
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Localization of nucleotide pyrophosphatase in the rat kidney (1986)
    Springer
    Histochemistry and cell biology 86 (1986), S. 207-210 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Hydrolysis of NAD by a nucleotide pyrophosphatase of renal membrane fractions has been reported previously. The aim of the present study was to localize this enzyme in the rat kidney. Nucleotide pyrophosphatase was assayed in glomeruli, in three parts of the proximal tubule and in four parts of the distal tubule dissected form freezedried sections. Nucleotide pyrophosphatase activity, expressed in μmol·min−1·mg protein−1, ranged between 9.8 and 32.3 in the proximal tubular segments and between 1.1 and 2.7 in the distal tubular segments. It was 3.4 in the glomeruli. The enrichement of the activity during the purification of brush border vesicles was measured. A tenfold higher specific activity was found in the brush border vesicles as compared to the renal cortical homogenates. Thus, most of the renal nucleotide pyrophosphatase appears to be localized in the luminal membrane of the proximal tubule. A permeabilization of the membrane did not increase the activity of brush border vesicles. This indicates that all catalytic sites are accessible at the outer surface of the membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00493389
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Distribution of ecto-5′-nucleotidase in the rat liver: effect of anaemia (1994)
    Springer
    Histochemistry and cell biology 101 (1994), S. 439-447 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In the kidney a striking parallel exists between the expression of ecto-5′-nucleotidase and of erythropoietin by renal fibroblasts. It was therefore hypothesized that the expression of ecto-5′-nucleotidase in fibroblasts might be controlled by oxygen tension. In order to test this hypothesis, we examined the distribution of the enzyme in a tissue which displays a defined zonation in respect to oxygen tension, namely in the liver; anaemia was used in order to exaggerate this zonation. The distribution of ecto-5′-nucleotidase was investigated by light and electron microscopy using enzyme and immunohistochemical methods in the livers of healthy and of anaemic rats. Anaemia was produced by haemolysis combined with X-ray irradiation. The enzyme was detected in the bile canaliculi, in the connective tissue of the portal triads and of the central veins, and in fat-storing cells probably corresponding to a special form of fibroblasts. In healthy animals the perisinusoidal ecto-5′-nucleotidase activity was slightly higher in the pericentral than in the periportal area of the acinus whereas the inverse was observed for the staining of bile canaliculi. Anaemia provoked an increase of ecto-5′-nucleotidase in fat-storing cells in the pericentral zone of the acinus and in fibroblasts around the central veins, resulting in steepended gradients along the sinusoids. The intralobular gradient of ecto-5′-nucleotidase in perisinusoidal cells and the effect thereon of anaemia suggest that the expression of the ecto-5′-nucleotidase might be directly or indirectly controlled by local oxygen tension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00269494
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Ecto-5′-nucleotidase is expressed by pericytes and fibroblasts in the rat heart (1995)
    Springer
    Histochemistry and cell biology 103 (1995), S. 227-236 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Ecto-5′-nucleotidase is anchored at the outer surface of cell membranes and thus its reaction product adenosine is released into the extracellular space. Extracellular adenosine displays via specific receptors a wide range of physiological effects in heart. There are discrepancies in the literature concerning the distribution of ecto-5′-nucleotidase in heart. Since we suspected that these may be due to technical problems, in the present study on ecto-5′-nucleotidase in rat heart we attempted to circumvent some technical pitfalls. Good preservation of the tissue with open capillary lumina, providing a clear identification of endothelium, was obtained by perfusion fixation. At the light microscopic level, the distribution of ecto-5′-nucleotidase studied by enzyme histochemistry and immunohistochemistry using a monoclonal and a polyclonal antibody yielded congruent results. The enzyme was rather homogeneously distributed throughout the myocardium, with a slightly higher incidence of stained cells in the outer thirds than in the inner third of the wall. Consistently high levels of ecto-5′-nucleotidase were seen only in interstitial cells. The walls of large vessels and heart muscle cells were constantly negative for ecto-5′-nucleotidase. The endothelia of capillaries were mostly negative but a few profiles occasionally displayed a weak immunoreaction. The interstitial cells staining positive for ecto-5′-nucleotidase could be identified as pericytes and as fibroblasts according to their shapes and localizations. The immunoreactivity of fibroblasts was confirmed by electron microscopy. These data indicate that adenosine may be formed extracellularly in the interstitium of the myocardium, where it would have direct access to important targets such as myocytes, arterioles and nerve endings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01454028
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Quantitative distribution of lysosomal hydrolases in the rat nephron (1979)
    Springer
    Histochemistry and cell biology 63 (1979), S. 245-251 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The activities of N-acetyl-β,d-glucosaminidase (NAG, EC 3.2.1.30),β,d-galactosidase (β-gal, EC 3.2.1.23) and acid phosphatase (ac-Pase, EC 3.1.3.2) were measured in the glomeruli, five segments of the proximal and four segments of the distal tubule of normal male Wistar rats. The activities of NAG andβ-gal are 3- to 5-fold higher in the first part of the proximal tubule than in other segments and very low in glomeruli. We propose that the distribution of these two glycosidases reflects the contribution of the different tubular segments to the reabsorption of glycoproteins. The maximal activity of ac-Pase was found in the straight part of the proximal tubule. It was only 1.5-fold higher than in the distal tubule. Moreover, the activity in glomeruli is rather high. We conclude that ac-Pase is not primarily involved in the handling of reabsorbed molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00644546
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    The activities of peroxisomal oxidases in periportal and perivenous zones of the rat liver acinus (1980)
    Springer
    Histochemistry and cell biology 69 (1980), S. 95-99 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using a new biochemical microassay the activities of three peroxisomal oxidases in single microdissected periportal and perivenous zones of the liver acinus were measured. Whereas urate oxidase is homogeneously distributed through the acinus, the activities of D-aminoacid oxidase and α-hydroxyacid oxidase are respectively 1.80-and 2.71-fold higher in the periportal hepatocytes than in the perivenous hepatocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00508370
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    The cellular specificity of lectin binding in the kidney (1982)
    Springer
    Histochemistry and cell biology 74 (1982), S. 521-530 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In order to estimate the usefulness of lectins in the study of the functional segmentation of the nephron, the sites of binding of five lectins were identified in the rat kidney. Lectin-peroxidase conjugates were applied to cryostat sections. The bound conjugates were stained with 3,3′-diaminobenzidine for light microscopical observation. Each lectin has a specific binding pattern along the nephron. Reversely, the different segments of the nephron defined by other histological methods can be identified on the basis of their affinity for lectins. The different parts of the thick ascending limb, namely the medullary segment, the cortical segment and the macula densa, can be distinguished even more readily with lectin histochemistry than with any other histochemical procedure. The binding of lectins to luminal membranes in some segments indicate the possibility to use lectins for the separation of particular cell types and for the modification of the transport properties of their membranes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00496666
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    The cellular specificity of lectin binding in the kidney (1982)
    Springer
    Histochemistry and cell biology 74 (1982), S. 531-540 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In order to estimate the usefulness of lectins in the study of the functional segmentation of the nephron, the sites of binding of four lectins were identified in the rabbit kidney. Lectin-peroxidase conjugates were applied to unfixed cryostat sections. The bound conjugates were stained with 3,3′-diaminobenzidine for light microscopical observation. Each lectin has a specific binding pattern along the nephron. The patterns generally fit in with the segmentation of the nephron established by conventional histology. However in the proximal tubule and in the thick ascending limb the lectin binding suggests functional transitions in histologically homogeneous tubular portions. In contrast to the other cell types of the connecting tubule and of the collecting duct the intercalated cells bind two lectins at their luminal membrane. Segmental differences in the lectin affinity of the basement membrane suggest that this structure has not only mechanical functions. The binding of lectins to luminal membranes in some segments indicate the possibility to use lectins for the separation of particular cell types and for modification of the transport properties of their membranes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00496667
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Immunolocalization of ecto-5′-nucleotidase in the kidney by a monoclonal antibody (1990)
    Springer
    Histochemistry and cell biology 95 (1990), S. 165-174 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A monoclonal antibody IgG, has been raised against ecto-5′-nucleotidase purified from rat kidney homogenate. The specificity of the antibody was verified by immunoprecipitation. The distribution of the corresponding antigen in the rat kidney was studied by immunocytochemistry (FITC and PAP technique) in 1 μm thick cryostat sections. The antibody reacted with the brush border of proximal tubules, the apical cell membrane and the apical cytoplasm of intercalated cells in connecting tubules and collecting ducts and with interstitial cells of the cortex. Among the interstitial cells exclusively stellate shaped fibroblasts were reactive whereas rounded interstitial cells (type II interstitial cells) as well as pericytes and endothelial cells of peritubular capillaries were unreactive. Compared to the staining intensity of the fibroblasts in the cortical labyrinth the reactivity of the fibroblasts in the medullary rays of the cortex was weak or absent. Interstitial cells of the entire medulla were unreactive. Concerning the fibroblasts in the periarterial connective tissue, those surrounding the larger arteries (arcuate arteries, cortical radial arteries) were negative, those alongside afferent and efferent arterioles were positive. Endothelia of lymphatic capillaries travelling within the periarterial connective tissue were also positive. All components of the juxtaglomerular apparatus were negative. The findings are consistent with an interstitial production of adenosine, available extracellularly and thus being able to reach the major target sites of adenosine, the smooth muscles of glomerular arterioles, including the granular cells at the glomerular vascular pole.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00266589
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Cellular components of the immune barrier in the spinal meninges and dorsal root ganglia of the normal rat: immunohistochemical (MHC class II) and electron-microscopic observations (1993)
    Springer
    Cell & tissue research 273 (1993), S. 209-217 
    Details
    ISSN: 1432-0878
    Keywords: Antigen-presenting cells ; Major histocompatibility complex class II (MHC class II) ; Macrophages ; Dendritic cells ; Meninges ; Dorsal root ganglia ; Spihal cord ; Rat (Wistar, SIV, Brown-Norway: Ch. Rivcr Wiga)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract This report deals with the distribution, morphology and specific topical relationships of bone-marrow-derived cells (free cells) in the spinal meninges and dorsal root ganglia of the normal rat. The morphology of these cells has been studied by transmission and scanning electron microscopy. Cells expressing the major histocompatibility complex (MHC) class II gene product have been recognized by immunofluorescence. At the level of the transmission electron microscope, free cells are found in all layers of the meninges. Many of them display characteristic ultrastructural features of macrophages, whereas others show a highly vacuolated cytoplasm and are endowed with many processes. These elements lack a conspicuous lysosomal system and might represent dendritic cells. Scanning electron microscopy has revealed that free cells contact the cerebrospinal fluid via abundant cytoplasmic processes that cross the cell layers of the pia mater and of the arachnoid. Cells expressing the MHC class II antigen are also found in all layers of the meninges. They are particularly abundant in the layers immediately adjacent to the subarachnoid space, in the neighbourhood of dural vessels, along the spinal roots and in the dural funnels. In addition to the meninges, strong immunoreactivity for MHC class II antigen is observed in the dorsal root ganglia. The ultrastructural and immunohistochemical findings of this study suggest the existence of a well-developed system of immunological surveillance of the subarachnoid space and of the dorsal root ganglia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00312822
    Location Call Number Expected 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...