ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Electronic Resource

Statistical mechanics basis of Macleod's formula (1990)

Boudh-Hir, M. E. ; Mansoori, G. A.

s.l. : American Chemical Society

The @journal of physical chemistry 〈Washington, DC〉 94 (1990), S. 8362-8364

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Source: ACS Legacy Archives

Topics: Chemistry and Pharmacology , Physics

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1021/j100384a068

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2

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5′-Nucleotidase in spinal meningeal compartments in the rat (1992)

Zenker, W. ; Rinne, B. ; Bankoul, S. ; [et al.]

Springer

Histochemistry and cell biology 98 (1992), S. 135-139

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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

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3

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Distribution of ecto-5′-nucleotidase in the rat liver: effect of anaemia (1994)

Schmid, T. C. ; Loffing, J. ; Hir, M. ; [et al.]

Springer

Histochemistry and cell biology 101 (1994), S. 439-447

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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

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4

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Localization of nucleotide pyrophosphatase in the rat kidney (1986)

Hir, M. ; Dubach, U. C. ; Angielski, S.

Springer

Histochemistry and cell biology 86 (1986), S. 207-210

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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

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5

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Immunolocalization of ecto-5′-nucleotidase in the kidney by a monoclonal antibody (1990)

Gandhi, R. ; Hir, M. ; Kaissling, B.

Springer

Histochemistry and cell biology 95 (1990), S. 165-174

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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

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6

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Distribution of 5′-nucleotidase in the renal interstitium of the rat (1989)

Hir, Michel ; Kaissling, Brigitte

Springer

Cell & tissue research 258 (1989), S. 177-182

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ISSN: 1432-0878

Keywords: Kidney ; 5′-Nucleotidase ; Adenosine ; Interstitium ; Fibroblasts ; Rat (Wistar)

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Summary The hydrolysis of 5′-AMP by 5′-nucleotidase is the main source of adenosine. In various tissues adenosine is a local mediator adjusting the organ work to the available energy. In the kidney it regulates renal hemodynamics, glomerular filtration rate and renin release via specific receptors of the arteriolar walls. By immunocytochemistry we identified interstitial and tubular sites of 5′-nucleotidase in the rat kidney. In the interstitium the enzyme was detected only in the cortical labyrinth, the compartment that comprises all arteriolar vessels besides other putative targets of adenosine. The 5′-nucleotidase-positive cells of the interstitium were identified as fibroblasts. The fibroblasts are in close contact with the tubules as well as with the vessels. Thus, any 5′-AMP released by the tubules into the interstitial space would be converted to adenosine in the direct vicinity of its assumed targets. Adenosine produced by tubular cells would hardly have access to its known targets, since 5′-nucleotidase is restricted to the luminal cell surface. Pathological events affecting the fibroblasts might influence renal function by modifying the interstitial adenosine production.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00223156

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7

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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)

Braun, Johann Sebastian ; Kaissling, Brigitte ; Hir, Michel ; [et al.]

Springer

Cell & tissue research 273 (1993), S. 209-217

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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

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