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  • 1
    Electronic Resource
    Electronic Resource
    Ionic conductances of cultured principal cell epithelium of renal collecting duct (1988)
    Springer
    Pflügers Archiv 412 (1988), S. 434-441 
    Details
    ISSN: 1432-2013
    Keywords: Collecting duct ; Principal cell ; Tissue culture ; Chloride conductivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The ionic conductive properties were studied of epithelia of collecting duct principal cells which had been grown in primary tissue culture from renal cortex/capsule explants. When pretreated with aldosterone (10−6 mol/l) and bathed on either surface with isotonic HCO 3 − -free Ringer's solution, the transepithelial voltage,V te, varied between −21 and −72 mV (apical surface negative) while the transepithelial resistance,R te, ranged from 0.4 to 1.5 kΩcm2. By 10:1 step-changes in Na+ concentration the apical cell membrane was shown to have a high conductivity for sodium, inhibitable by amiloride, 10−6 mol/l. However, contrary to observations in natural collecting duct under control conditions, amiloride never reversed the polarity ofV te even at 10−4 mol/l. Both the apical and the basolateral cell membranes were conductive for potassium and both conductivities were inhibitable by Ba2+ (5 mmol/l). 10:1 reduction of apical Cl− concentration strongly hyperpolarizedV te with a monophasic time course suggesting the presence of a paracellular shunt conductance for Cl−. In addition there may be a small Cl− conductance present in the apical cell membrane since apical application of the chloride channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPAB) at 10−7 mol/l produced a minute but significant hyperpolarization. On the other hand, 10:1 reduction of basolateral Cl− concentration caused a biphasic change inV te (initial depolarization, followed by repolarization) which indicates the presence of a large Cl− conductance in the basolateral cell membrane. The latter was not inhibitable by 10−7 mol/l NPPAB. Higher concentrations of this and of an other Cl− channel blocker produced non-specific effects. In conclusion, our studies of a pure principal cell epithelium confirm findings described for the intact cortical collecting duct and add new information concerning chloride conductivity and related blocking agents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01907564
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  • 2
    Electronic Resource
    Electronic Resource
    Electrical properties of renal collecting duct principal cell epithelium in tissue culture (1986)
    Springer
    Pflügers Archiv 406 (1986), S. 380-386 
    Details
    ISSN: 1432-2013
    Keywords: Collecting duct ; Principal cell ; Tissue culture ; Aldosterone ; Amiloride ; Sodium transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Whereas collecting duct epithelium in vivo is composed of principal and intercalated cells, we grew a pure principal cell epithelium using a new technique involving tissue culture. These principal cells were derived from collecting duct anlagen of newborn rabbits. We investigated the electrical properties of such epithelia in a newly designed lucite double-chamber with an inner opening of 0.08 cm2. Our observations were: 1) mean transepithelial resistanceR te was 0.83±0.2 kΩcm2 at 37° C and after preincubation in aldosterone; 2) mean transepithelial potential differenceV te was low and variable under standard conditions and at room temperature but increased to −59.5±4.4 mV (sign referring to polarity of apical surface) after preincubation in 10−6 mol/l aldosterone and at 37° C; 3) 10−6 mol/l amiloride added to the apical perfusion fluid largely abolished thisV te while increasingR te by 120%; 4) experiments with 5×10−3 mol/l BaCl2 in the apical perfusion fluid failed to changeR te andV te significantly. This principal cell epithelium therefore has characteristics of a “tight” epithelium with active sodium transport; however, its electrical properties differ from those of the isolated perfused collecting duct segment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00590940
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  • 3
    Electronic Resource
    Electronic Resource
    Direkte, differentielle Bestimmung von Hippursäure und Methyl-Hippursäure-Isomeren im Urin mit der Hochdruckflüssigkeits-Chromatographie (1980)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 301 (1980), S. 20-24 
    Details
    ISSN: 1618-2650
    Keywords: Best. von Hippursäure, Methylhippursäuren in Harn ; Chromatographie, HPLC ; reversed phase, Direktinjektion, UV-Detektion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mit dem hier beschriebenen hochdruckflüssigkeits-chromatographischen Verfahren ist die differentielle Analyse der Methylhippursäure-Isomeren neben der Hippursäure möglich. Verdünnte Harnproben werden dabei direkt injiziert. Als Trennsystem wird die Reversed-Phase-Chromatographie verwendet. Der Einsatz zweier hintereinander geschalteter UV-Detektoren mit verschieden eingestellten Wellenlängen ermöglicht die fraktionierte Messung der Methylhippursäure-Isomeren. Die analytischen Zuverlässigkeitskriterien der Methode entsprechen den Erfordernissen einer Routinemethode an das arbeitsmedizinisch-toxikologische Laboratorium. Die Präzision in der Serie beträgt 9%, die Richtigkeit 98–124%. Als Nachweisgrenzen für die Carbonsäuren ermittelten wir Konzentrationen von ca. 10 μg/ml Harn. Untersuchungen an beruflich gegenüber Xylolen exponierten Personen haben ergeben, daß ein Verhältnis des m- zum p-Isomeren von ca. 3∶1 besteht. Die Ausscheidungsrate des o-Isomeren liegt wesentlich niedriger.
    Notes: Summary The described high-pressure liquid chromatographic method (reversed phase) permits a differentiating analysis of methyl-hippuric acid isomers and hippuric acid. Diluted urine samples are directly injected. The use of two UV-detectors adjusted to different wavelengths and connected in series allows the fractionated measurement of methylhippuric acid isomers. The analytical reliability criteria of this method are in accordance with the requirements to be met by a laboratory for occupational medicine. The precision within one run is 9%, the accuracy 98–124%. The detection limits of the carbonic acids were found to be in the range of approximately 10μg/ml urine. Examinations of persons exposed to xylene showed a m-/p-isomer ratio of about 3∶1. The excretion rate of the o-isomer is extremely lower.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00481266
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    Paper (German National Licenses)
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