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  • Kidney
  • Springer  (10)
  • 1970-1974  (10)
  • 1971  (10)
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Publisher
  • Springer  (10)
Years
  • 1970-1974  (10)
Year
  • 1
    ISSN: 1591-9528
    Keywords: Kidney ; Glomerulus ; Isolation technique ; Ultrastructure ; Niere ; Glomerulum ; Isoliertechnik ; Ultrastruktur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Mit einer im Detail angegebenen, mechanisch schonenden Sieb-Methode wurden aus Rattennieren Glomerulumfraktionen mit einem Reinheitsgrad von 95–98% gewonnen. Dabei wurden 10 verschiedene Spülmedien benützt und ihr Einfluß auf die Ultramorphologie der Glomerula elektronenmikroskopisch kontrolliert. Nach Verwendung einer Krebs-Henseleit-Bicarbonat-Lösung mit einem pH von 7,9 ist mit der irreversiblen Schädigung des überwiegenden Teiles der Podocyten zu rechnen. Elektronenmikroskopisch befriedigende Resultate ließen sich mit einer Krebs-Henseleit-Bicarbonat-Lösung pH 7,4+3% Dextran erzielen, bei der ca. 60% der in der Fraktion enthaltenen Podocyten intakt blieben. Die restlichen 40% Podocyten waren in erster Linie mechanisch zerstört. Während Endothel- und Mesangiumzellen nach den verschiedenen Spülmedien kaum morphologische Veränderungen aufweisen, können also die Podocyten je nach Spülmedium überwiegend zerstört werden oder zu etwa 60% erhalten bleiben.
    Notes: Summary Fractions with 95–98% glomeruli have been obtained from rat kidneys with a sieve method described in detail. 10 different rinsing solutions have been used during isolation and their influence on the ultrastructure of the glomeruli has been controlled electron microscopically. The podocytes exhibit a strong edema of cytoplasm and nucleus, reaching up to cytolysis, after Krebs-Henseleit-bicarbonate-, Krebs-Ringer-phosphate- and Robinson-solution. After a Krebs-Henseleit-bicarbonate solution with pH 7.9 instead of pH 7.4 most podocytes have been damaged irreversibly. A satisfying ultrastructure resulted after solutions with a higher colloid osmotic pressure or osmotic pressure. The best results have been obtained with Krebs-Henseleit-bicarbonate solution pH 7.4+3% dextran (mol wt 40000), after which about 60% of the podocytes have been calculated to be intact. 40% of the podocytes in this fraction mainly were mechanically damaged. While endothelium and mesangium show only minor structural aberrations after the different rinsings, thus most podocytes are damaged irreversibly after Krebs-Henseleit-bicarbonate pH 7.9, and on the other hand about 60% may be intact after Krebs-Henseleit-bicarbonate pH 7.4+3% dextran.
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  • 2
    ISSN: 1432-2013
    Keywords: Na-K ATPase ; Liver ; Kidney ; Diurnal Variation ; Na-K ATPase ; Leber ; Niere ; Tagesrhythmus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a systematic investigation the course of the activities of the Na-K activated ATPase and the Mg ATPase enzyme systems in rat liver and kidney were studied. In the liver the activities of both enzyme systems were on a significantly higher level (22 and 15% resp.) during the evening hours (4:00 p. m. to 2:00 a. m.). In the kidney a significantly lower level (13%) of Na-K ATPase activity was found during the night (10:00 p. m. to 8:00 a. m.), while Mg ATPase activity did not vary significantly. The periods of raised enzyme activity in liver and in kidney did not coincide. The results are discussed in relation to literature data on diurnal variations of metabolic activities in general.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 324 (1971), S. 1-25 
    ISSN: 1432-2013
    Keywords: Adenosine Triphosphatase ; Plasma Membrane Enriched Fraction ; Microsomes ; Kidney ; ATPase ; zellmembranangereicherte Fraktion ; Mikrosomen ; Niere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A fraction enriched with plasma cell membranes (PMF) was isolated from rat kidney homogenate by differential centrifugation. Before NaJ treatment electron micrographs of the preparation showed a membraneous fraction with only a small contamination of mitochondria. After treatment with NaJ the residual PMF exhibited a low microsomal glucose 6-phosphatase activity. Marker enzymes of other subcellular fractions were not detected. The NaJ extracted PMF revealed a high specific activity of ATPase, 91% of which was stimulated by Na+ and K+. The MgNaK-ATPase was characterized by Michaelis Menten kinetics. In contrast, Hill coefficients (“n”) of NaK-ATPase for the activation by Na+, K+ and Mg-ATP were greater than one. Experiments with various nucleotide tri-, di- and monophosphates revealed a high substrate specificity of the NaK-ATPase. The pH optimum was in the range of 7.2. SH-reagents and ouabain depressed the Na+ and K+ stimulated enzyme activity. PMF isolated from rat kidneys exhibited an acylphosphatase and a nitrophenylphosphatase activity, both of which were stimulated by K+. Furthermore 5′-nucleotidase and leucine aminopeptidase activities were present in the fraction.—Thus, NaK-ATPase of the PMF revealed the typical properties of the NaK-ATPase demonstrated in the microsomal preparations, which has been referred to by Skou (1965) as the enzymatic basis of active cation transport.
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  • 4
    ISSN: 1432-2013
    Keywords: Kidney ; Na+−K+-ATPase ; Sodium Transport ; Volume Expansion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The role of renal Na+−K+-ATPase in the acute changes in sodium reabsorption caused by isotonic volume expansion was evaluatedin vivo andin vitro in the rat and the dog. Duringin vivo volume expansion with isotonic saline in the rat, renal medullary Na+−K+-ATPase specific activity increased, while the simultaneously determined cortical Na+−K+-ATPase specific activity and kinetics remained unchanged. Furthermore, experimentsin vitro failed to demonstrate a circulating inhibitor of renal Na+−K+-ATPase both in plasma dialysates from volume-expanded rats and in plasma dialysates concentrated 20-fold by ultrafiltration from volume-expanded dogs. These results suggest that the decreased proximal tubular reabsorption of sodium during volume expansion is not mediated by inhibition of renal cortical Na+−K+-ATPase. The acute increment in medullary Na+−K+-ATPase observed could represent an adaptive response to increased sodium reabsorption by the loops of Henle, and raises the possibility that this enzyme may participate in relatively rapid adjustments in the transport of sodium by the renal tubule.
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  • 5
    ISSN: 1432-2013
    Keywords: Kidney ; Renal Artery ; Blood Flow Velocity ; Isoproterenol ; β-adrenergic Receptors ; Niere ; Nierenarterie ; Nierendurchblutung ; Isoproterenol ; β-Receptoren
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An wachen Hunden wurden mit einem Miniaturdruckaufnehmer der Blutdruck in der abdominalen Aorta und mit einem elektromagnetischen Flußmesser die Strömungsgeschwindigkeit in der linken Nierenarterie gemessen. Die Reaktion der Nierenstromstärke und des Blutdrucks auf rasche (〈1 sec) Injektion von 2,5, 5,0, 10,0 und 20,0 μg Isoproterenol in die abdominale Aorta proximal der Nierenarterie wurde untersucht. Bei allen vier Dosen wurde regelmäßig eine Steigerung der Nierendurchblutung und eine Abnahme des arteriellen Blutdrucks beobachtet. Die maximale Widerstandssenkung betrug im Mittel 25–30%. Während der ersten 6 sec nach Injektion erreichte die Nierenstromstärke bei noch unverändertem arteriellen Mitteldruck einen signifikant erhöhten Wert. Ebenso fand sich eine signifikant erhöhte Stromstärke, nachdem der Blutdruck sein Ausgangsniveau wieder erreicht hatte. Nach β-Blockade mit 0,5 mg/kg Propranolol hatte Isoproterenol in den verwendeten Dosen keinen Einfluß auf die Nierenstromstärke und den arteriellen Blutdruck. Das Ausmaß der beobachteten Vasodilatation läßt sich durch Autoregulation nicht erklären. Aus den Experimenten wird geschlossen, daß Isoproterenol (2,5 bis 20,0 μg i.a.) am wachen Hund in Ruhe β-Receptoren der Nierengefäße erregt.
    Notes: Summary In unanesthetized dogs abdominal aortic pressure was measured with an implanted miniature transducer, left renal artery flow velocity by an electromagnetic flowmeter. The effect of rapid injections (〈1 sec) of 2.5, 5.0, 10.0 and 20.0 μg isoproterenol into the abdominal aorta proximal to the renal artery on kidney blood flow and arterial blood pressure was investigated. Isoproterenol in every dose used regularly caused kidney blood flow to increase and arterial blood pressure to fall. The maximum decrease of resistance to flow in the average amounted to 25–30%. During the first 6 sec after drug injection kidney blood flow was already significantly elevated while arterial blood pressure was still unchanged.A significantly augmented kidney blood flow was also found when blood pressure had returned again to its original level. After β-blockade (0,5 mg/kg propranolol) isoproterenol (2.5–20.0 μg i.a.) had no effect on kidney blood flow and arterial blood pressure. The extent of the vasodilation cannot be attributed to autoregulation. It is concluded, that isoproterenol (2.5–20.0 μg i.a.) causes a β-adrenergic vasodilation in the kidney vasculature of the resting conscious dog.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 120 (1971), S. 29-36 
    ISSN: 1432-0878
    Keywords: Kidney ; Macula densa ; Juxtaglomerular apparatus ; Bird ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The macula densa (MD) site of the kidney, at which the distal tubule is attached to the vascular pole of the glomerulus, was examined with the light microscope in domestic fowl and Japanese quail; and in the fowl also with the electron microscope. The characteristics of mammalian MD cells, as reported in the literature, are compared with those of the cells in the avian MD site. The avian cells possess some of the characteristics of mammalian MD cells and they are distinguishable from the cells in adjacent portions of the distal tubule. The Golgi system in the avian cells is apical to the nucleus, unlike in mammals where its location is basal. The cells in the avian MD sites can be considered as structurally transitional between the typical MD cells in mammals and the ordinary cells of the distal tubule. These findings are discussed in relation to the function of the avian kidney and to its control by the renin mechanism.
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  • 7
    ISSN: 1432-0878
    Keywords: Kidney ; Mesangium ; Hibernator ; Juxtaglomerular apparatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The mesangial and juxtaglomerular cells were studied in kidneys of hibernating and non-hibernating ground squirrels, Citellus tridecemlineatus. In the hibernating animal, as compared with the non-hibernating, the mesangial cells show signs of increased activity. The cells are relatively larger, and numerous vacuoles appear in the cytoplasm. The juxtaglomerular cells also show signs of hyperactivity. Secretion droplets, mitochondria and free ribosomes increase in number and the endoplasmic reticulum becomes dilated. It is postulated that during hibernation, increased activity of mesangial cells slows glomerular filtration by absorption of filtrate into the mesangial matrix, and increased activity of juxtaglomerular cells results in increased renin secretion which in turn may stimulate hypersecretion of aldosterone to conserve sodium for water balance mechanisms necessary at the time.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 114 (1971), S. 1-21 
    ISSN: 1432-0878
    Keywords: Kidney ; Elasmobranchs ; Glomerular Vessels ; Tubular Secretion ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Glomerula und Hauptstücke der Elasmobranchierniere fallen nach lichtmikroskopischen Studien durch strukturelle Besonderheiten auf, die möglicherweise mit der physiologischen Uraemie dieser Tiergruppe in Zusammenhang stehen. Um weitere morphologische Grundlagen für spätere cytochemische und physiologische Untersuchungen zu gewinnen, haben die Autoren die genannten Nephronabschnitte elektronenmikroskopisch untersucht. Folgende Befunde wurden erhoben: 1. Die erstaunliche Dicke der Glomerulumgefäße der Elasmobranchier — sie beträgt durchschnittlich 7 μ — beruht auf der Ausbildung einer zellreichen Schicht (Durchmesser durchschnittlich 6 μ) zwischen Podozyten und Endothel. 2. Die Podozyten tragen Einzelcilien, die in den Kapselraum hineinragen, und werden von Strähnen zarter, etwa 80 Å dicker Filamente durchzogen. Möglicherweise handelt es sich um Myofilamente. Zwischen den Füßchen der Podozyten auf der Basalmembran kommen Schlitzmembranen vor. 3. Die Mittelschicht der Gefäßwand entspricht einer stark verdickten Basalmembran, in die außer Kollagenfibrillen Zellen eingebettet sind. Die Mehrzahl dieser intralamellären Zellen besteht aus verästelten Elementen, deren Ausläufer sich innerhalb der Membran ausbreiten. Im Gegensatz zu früheren Aussagen, die sich auf lichtmikroskopische Beobachtungen stützen, werden diese Zellen als fibrozytäre Elemente und nicht als glatte Muskelzellen gedeutet. Eine zweite intralamelläre Zellart, deren Elemente keine Ausläufer besitzen, fällt durch starke Entwicklung von Ergastoplasma auf. 4. Das relativ dicke Endothel der Glomerulumgefäße besitzt eine stark zerklüftete Oberfläche, seine Pseudofenestrierung ist weniger regelmäßig als in den Glomerula höheren Formen ausgebildet. 5. Verschiedene Zustandsbilder einer Abschnürung von vacuolär strukturierten Blasen und von Protuberanzen, die möglicherweise das Äquivalent einer apokrinen Extrusion aus den Hauptstückzellen sind, werden beschrieben. Die Frage bleibt offen, ob dieser Vorgang etwas mit der Abgabe harnpflichtiger Substanzen in das Lumen des Kanälchens zu tun hat. Es handelt sich bei diesen Strukturen nicht um Fixationsartefakte. 6. Die von Lichtmikroskopikern beschriebenen „Basalreifen“ des Nierenkanälchens entsprechen leistenartigen Erhebungen der Innenfläche der Basalmembran. Das Bild der „basalen Kittfäden“ dürfte durch die Cytoplasmapartien zwischen den Basalreifen hervorgerufen werden.
    Notes: Summary According to light microscopical studies glomerula and proximal convoluted tubules of the elasmobranch kidney are characterized by structural peculiarities, which possibly are related to the physiological uremia of this group of animals. In order to obtain morphological fundamentals for cytochemical and physiological studies, the authors have investigated the above mentioned parts of the nephron with the electron microscope. The results are as follows: 1. The remarkable thickness of the glomerular tufts in the elasmobranchs—averaging 7 μ—is due to the presence of a cell-rich layer (diameter about 6 μ) between podocytes and endothelium. 2. The podocytes bear individual cilia protruding into the capsular space. They further contain bundles of fine filaments (diameter approximately 80 Å) which possibly are myofilaments. Between the feet of the podocytes slit membranes occur on the surface of the basement lamina. 3. The medium layer of the vascular wall corresponds to a strongly thickened basement lamina, into which besides collagen fibrils and fuzzy material different cells are embedded. The majority of these intralamellar cells consists of branched elements the processes of which spread inside the membrane. In contrast to earlier statements, which were based on light microscopical observations, these cells are interpreted to represent fibrocytic elements and not smooth muscle cells. A second intralamellar cell type which does not possess any processes, is marked by well developed cisternae of rough endoplasmic reticulum. 4. The relatively thick endothelium of the glomerular vessels possesses a rugged surface, its pseudofenestration beeing less regular than in glomerular capillaries of higher vertebrates. 5. Vesiculated spherical bodies, swollen cellular apices and protuberances apparently being pinched off in the proximal convoluted tubule—possibly equivalents of an apocrine extrusion—are described. The authors are of the opinion that these structures do not represent artifacts caused by fixation. It remains on open question, whether this extrusion contributes to the composition of the tubular urine. 6. The “Basalreifen” of the kidney tubule as have been described by light microscopists, correspond to crests of the inner surface of the basement lamina, the “basale Kittfäden” to the strips of cytoplasm between these “Basalreifen”.
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  • 9
    ISSN: 1432-0878
    Keywords: Kidney ; Triturus cristatus ; Juxtaglomerular apparatus ; Cell types
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1)As in mammals, the juxtaglomerular apparatus of the Newt (Triturus cristatus) is composed by cells of the media of the afferent glomerular arteriole and by cells of the intermediary tubule. 2) The cells of the media of the glomerular arteriole are of two different types: granular and agranular cells. 3) The intermediary tubule is formed by dark and light cells. 4) Part of interrenal body is located close to glomerular arteriole and intermediary tubule.
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  • 10
    ISSN: 1432-1912
    Keywords: Carbohydrate Metabolism ; Kidney ; Enzymic Determination of Substrates ; 6-Aminonicotinamide ; Adrenalectomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After application of 6-aminonicotinamide (6-AN), a strong accumulation of 6-phosphogluconate was found in rat kidney. The accumulation of 6-phosphogluconate influences the activity of the phosphoglucose isomerase. The enzymic determination of the substrate concentrations of the carbohydrate metabolism after application of 6-AN revealed that fructose-6-phosphate and lactate as well as phosphoenolpyruvate are significantly increased in the kidney as compared to the controls. The increase in phosphoenolpyruvate might be caused by stimulated gluconeogenesis, as the application of 6-AN increases the release of corticosterone from the adrenal cortex. After adrenalectomy, the accumulation of 6-phosphogluconate is decreased, the ratio glucose-6-phosphate/fructose-6-phosphate is normalized, and also the values for lactate and phosphoenolpyruvate decrease. The effects of adrenaline seem to involve the passage of glucose through the pentose phosphate pathway. There is probably a relationship between the blockade of the oxidative pentose phosphate pathway and the stimulation of gluconeogenesis in the kidney, the mechanism of which is unknown. In contrast to the findings in the brain, no changes could be established in the concentrations of citrate and 2-oxoglutarate.
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