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M Le Hir - One of the best experts on this subject based on the ideXlab platform.
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Distribution of ecto-5′-Nucleotidase in the rat liver: effect of anaemia
Histochemistry, 1994Co-Authors: T. C. Schmid, M Le Hir, Johannes Loffing, Brigitte KaisslingAbstract: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.
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Distribution of ecto-5'-Nucleotidase in the rat liver : effect of anaemia
Histochemistry, 1994Co-Authors: T. C. Schmid, M Le Hir, Johannes Loffing, Brigitte KaisslingAbstract: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.
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A soluble 5'-Nucleotidase in rat kidney. Stimulation by decavanadate.
Biochemical Journal, 1991Co-Authors: M Le HirAbstract:A soluble 5′-Nucleotidase was identified in rat kidney and partially purified. Compared with 5′-IMP, 5′-AMP was a poor substrate. The affinity for 5′-IMP was very low (S0.5 greater than 1 mM) in the absence of an activator, and it was much increased (S0.5 = 0.1 mM) by 2,3-bisphosphoglycerate (2,3-DPG). ATP and bisadenosyl tetraphosphate were further activators. The pH optimum was 6.3. Those properties suggest that the renal soluble 5′-Nucleotidase is identical with the ‘high-Km’ 5′-Nucleotidase purified previously from liver, heart and erythrocytes. Decavanadate (100 nM) increased the rate of hydrolysis of 1 mM-5′-IMP 16-fold. The effect was specific for the decameric form of vanadate, since it was not reproduced by either decavanadate-free orthovanadate or pervanadate. Half-maximal activation was obtained at 1.4 nM-decavanadate. Decavanadate increased the affinity of the soluble 5′-Nucleotidase for 5′-IMP. The effects of 2,3-DPG and of vanadate were not additive. Thus decavanadate probably influences the soluble 5′-Nucleotidase in the same way as 2,3-DPG, but with a much higher potency.
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The soluble 'low-Km' 5'-Nucleotidase of rat kidney represents solubilized ecto-5'-Nucleotidase.
The Biochemical journal, 1991Co-Authors: G Piec, M Le HirAbstract:A soluble 'low-Km' 5'-Nucleotidase has been described previously in several organs. It has been presumed to be of cytosolic origin and thus to play a role in the intracellular production of adenosine. Its catalytic properties are similar to those of the ecto-5'-Nucleotidase of cell membranes. In the present study we compared molecular properties of the two enzymes in the kidney of the rat. The Mr of the main peak of soluble 'low-Km' 5'-Nucleotidase in gel-filtration chromatography was similar to that of the ecto-5'-Nucleotidase solubilized by a phosphatidylinositol-specific phospholipase C from renal brush-border membranes. In phase-partition experiments using Triton X-114, the soluble enzyme appeared to be hydrophobic. Its hydrophobicity was decreased on treatment with a phosphatidylinositol-specific phospholipase C, suggesting that the soluble 'low-Km' 5'-Nucleotidase contains the phosphatidylinositol anchor which is characteristic for the ecto-enzyme. An anti-ecto-5'-Nucleotidase antiserum provoked an almost complete inhibition of the soluble enzyme. Immunoblotting using anti-ecto-5'-Nucleotidase antiserum revealed in the high-speed supernatants a polypeptide with a similar Mr to the subunit of the ecto-5'-Nucleotidase. The soluble 'low-Km' 5'-Nucleotidase, like the ecto-5'-Nucleotidase, bound specifically to concanavalin A. We conclude that the soluble 'low-Km' 5'-Nucleotidase is not a cytosolic enzyme, but that it most probably originates from the solubilization of the ecto-5'-Nucleotidase, and that it therefore cannot participate in the intracellular production of adenosine.
Tsutomu Araki - One of the best experts on this subject based on the ideXlab platform.
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Plasma 5'-Nucleotidase activities increase in women with hyperemesis gravidarum.
Clinical biochemistry, 2002Co-Authors: Yoshio Yoneyama, Yasuo Otsubo, Hajime Kobayashi, Makiko Kato, Hiromitsu Chihara, Takashi Yamada, Tsutomu ArakiAbstract:Abstract Objectives To investigate plasma activities of 5′-Nucleotidase, a key enzyme in the production of adenosine and evaluate the relationship between changes in 5′-Nucleotidase activities and pregnancy-related hormones, estrogen, progesterone and human chorionic gonadotropin (hCG) in women with hyperemesis gravidarum. Design and methods Plasma 5′-Nucleotidase activities and estradiol, progesterone and hCG levels were measured in 21 women with hyperemesis gravidarum and normal pregnancies, matched for age, parity and gestational week. Results In women with hyperemesis gravidarum, plasma 5′-Nucleotidase activities averaged 8.1 ± 0.6 IU/L, which were significantly increased compared to those in normal pregnant women (5.5 ± 0.5 IU/L)( p Conclusions The increase of plasma 5′-Nucleotidase activities may be at least partly attributed to elevations of pregnancy-related hormones, suggesting changes in purine metabolism in women with hyperemesis gravidarum.
Yoshio Yoneyama - One of the best experts on this subject based on the ideXlab platform.
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Plasma 5'-Nucleotidase activities and uric acid levels in women with pre-eclampsia.
Gynecologic and obstetric investigation, 2002Co-Authors: Yoshio Yoneyama, Shunji Suzuki, Rintaro Sawa, Yasuo Otsubo, Atsushi Miura, Yoshimitsu Kuwabara, Hiroshi Ishino, Yasuko Kiyokawa, Daisuke Doi, Koichi YoneyamaAbstract:The present study investigated plasma activity of 5'-Nucleotidase, a key enzyme in the production of adenosine, in pre-eclampsia, and evaluated the relationship between changes in 5'-Nucleotidase activity, and levels of uric acid, endproduct of the purine metabolism, and the severity of pre-eclampsia. We measured plasma 5'-Nucleotidase activities and uric acid levels in women with 18 normal pregnancies, mild and severe pre-eclampsia. In mild and severe pre-eclampsia, plasma 5'-Nucleotidase activities and uric acid levels were significantly increased compared with those in normal pregnancy (p < 0.05). Plasma 5'-Nucleotidase activity increased according to increases in uric acid levels and the severity of pre-eclampsia. These results suggest that increased plasma 5'-Nucleotidase activity may, at least in part, be related to changes in purine metabolism in pre-eclampsia.
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Plasma 5'-Nucleotidase activities increase in women with hyperemesis gravidarum.
Clinical biochemistry, 2002Co-Authors: Yoshio Yoneyama, Yasuo Otsubo, Hajime Kobayashi, Makiko Kato, Hiromitsu Chihara, Takashi Yamada, Tsutomu ArakiAbstract:Abstract Objectives To investigate plasma activities of 5′-Nucleotidase, a key enzyme in the production of adenosine and evaluate the relationship between changes in 5′-Nucleotidase activities and pregnancy-related hormones, estrogen, progesterone and human chorionic gonadotropin (hCG) in women with hyperemesis gravidarum. Design and methods Plasma 5′-Nucleotidase activities and estradiol, progesterone and hCG levels were measured in 21 women with hyperemesis gravidarum and normal pregnancies, matched for age, parity and gestational week. Results In women with hyperemesis gravidarum, plasma 5′-Nucleotidase activities averaged 8.1 ± 0.6 IU/L, which were significantly increased compared to those in normal pregnant women (5.5 ± 0.5 IU/L)( p Conclusions The increase of plasma 5′-Nucleotidase activities may be at least partly attributed to elevations of pregnancy-related hormones, suggesting changes in purine metabolism in women with hyperemesis gravidarum.
Ardesio Floridi - One of the best experts on this subject based on the ideXlab platform.
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Extraction and purification of ecto-5'-Nucleotidase from human lymphocytes.
Advances in experimental medicine and biology, 2000Co-Authors: Enrico Marinello, Filippo Carlucci, Antonella Tabucchi, Marcello Coli, Ardesio Floridi, Francesca Rosi, Giuliano Cinci, Carlo FiniAbstract:Ecto-5’ -Nucleotidase is an extracellular enzyme which is anchored to the plasma membrane of various cells, including human lymphocytes through a glycosylphosphatidylinositol (GPI) linkage. The enzyme dephosphorylates purine and pyrimidine nucleoside monophosphates to the corresponding nucleosides and generates adenosine from extracellular AMP. In addition to its function as an enzyme, the ecto-5’ -Nucleotidase mediates costimulatory signals in T cells, lymphocyte adhesion to endhotelium, and has a role in controlling B cell-follicular dendritic cell interactions. Ecto-5’ -Nucleotidase is recognized as a maturation marker for both T and B lymphocytes. Abnormally low ecto-5’-Nucleotidase activity has been found on lymphocytes of pat ients suffering with a variety of immunodeficiency diseases characterized by a block in lymphocyte maturation 1. In previous studies we found a strong reduction of ecto-5’-Nucleotidase activity in lymphocytes from patients affected by B-cell chronic lymphocytic
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Purification of 5′-Nucleotidase from human seminal plasma
Biochimica et biophysica acta, 1991Co-Authors: Carlo Fini, Marcello Coli, Ardesio FloridiAbstract:Abstract 5′-Nucleotidase from human seminal plasma was purified to electrophoretic homogeneity and some of its kinetic and molecular properties compared with those of 5′-Nucleotidase from bull seminal plasma. The purification of the enzyme was achieved by using the same affinity chromatography media (Con A-Sepharose and AMP-Agarose or ADP-Agarose) previously used for the purification of bull seminal plasma 5′-Nucleotidase (Fini, C., Ipata, P.L., Palmerini, C.A. and Floridi, A. (1983) Biochim. Biophys. Acta 748, 405–412). However, in the present purification procedure no detergent was used as it had been necessary for the purification of the bovine enzyme. The experimental data reveal some main differences between these two enzymes; first, the human enzyme seems to be constituted of a single polypeptide chain of about 71 kDa, while the 5′-Nucleotidase of bull seminal plasma, in non denaturing detergent solutions, is a homodimer of about 160 kDa. Another most remarkable difference is that the human enzyme does not seem to contain a phosphatidylinositol anchoring system like the one present in the bovine enzyme and in 5′-Nucleotidase of different sources (Low, M.G. (1987) Biochem. J. 244, 1–13). Finally, the AMPase activity of 5′-Nucleotidase from human seminal plasma is not affected by dithiothreitol which, on the contrary, is a powerful inhibitor of the bovine enzyme causing the dissociation of its subunits which are held together by disulphide bridges (Fini, C., Minelli, A., Camici, M. and Floridi, A. (1985) Biochem. Biophys. Acta 827, 403–409).
Muhammad Ashraf - One of the best experts on this subject based on the ideXlab platform.
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Interaction of singlet oxygen with 5'-Nucleotidase in rat hearts.
Journal of molecular and cellular cardiology, 1995Co-Authors: Xiaolin Zhai, Xiaobo Zhou, Muhammad AshrafAbstract:This study was aimed to determine whether singlet oxygen (1O2) attenuates 5-Nucleotidase activity in the ischemic myocardium. Isolated rat hearts were exposed to either exogenous1O2produced by irradiating rose bengal or 40-min ischemia and reperfusion. Ecto-5-Nucleotidase activity was inhibited by exogenous1O2(3.74±0.38μmol/min/g dry weight), when compared with normal control (7.52±0.41μmol/min/g dry weight;P
