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  • 1995-1999  (6)
  • 1965-1969  (3)
  • 1950-1954
  • Inorganic Chemistry  (3)
  • Cell & Developmental Biology  (2)
  • Human nasal epithelium  (2)
  • leaky epithelium  (2)
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  • 1
    Electronic Resource
    Electronic Resource
    Ionentransporte über die Nasen- und Nasennebenhöhlenschleimhaut bei Mukoviszidose und chronischer Sinusitis (1999)
    Springer
    HNO 47 (1999), S. 157-166 
    Details
    ISSN: 1433-0458
    Keywords: Schlüsselwörter Mukoviszidose ; Zystische Fibrose ; Menschliches Nasalepithel ; Epithelialer Na+-Kanal ; Cl ; -Sekretion ; Key words Cystic fibrosis ; Human nasal epithelium ; Epithelial Na+ channels ; Cystic fibrosis transmembrane conductance regulator ; Cl ; secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Cystic fibrosis (CF) is the most commonly inherited disease in Caucasians and is caused by a mutation in the gene encoding a membrane transport protein. This cystic fibrosis transmembrane conductance regulator (CFTR) is thought to be an apical Cl– channel activated by intracellular cAMP. Most recent findings suggest that CFTR is more than a pure Cl– channel and might be involved in the regulation of other transport systems. In the present study we show that CFTR as a Cl– channel plays only a minor role in primary cultured human nasal epithelium derived from non-CF and CF patients. These findings are especially of interest for non-CF human nasal epithelia in which CFTR is correctly inserted. In both tissues Cl– secretion is negligible as compared with Na+ absorption. We confirm and expand our previous observations that Na+ absorption in human nasal epithelium is the dominant ion transport process and that Cl– secretion is detectable in both CF and non-CF tissue. Moreover, we show that cAMP and ATP were not able to stimulate any silent Cl– channels in CF or non-CF human nasal epithelial cells. We further give evidence that in human nasal CF and non-CF epithelium Na+ absorption is mediated by epithelial Na+ channels (ENaC) that are either different from those of other epithelia or which exhibit altered regulation. These differences between Na+ channels of human nasal epithelium and ”classical” epithelial Na+ channels include lack of activation by the intracellular second messenger cAMP and the steroid hormone aldosterone. We show further that human nasal Na+ channels are inhibited by Cl–-channel blockers and exhibit a different pharmacology towards common Na+ channel blockers.
    Notes: Zusammenfassung Mukoviszidose [zystische Fibrose (CF)] ist die häufigste Erbkrankheit in der kaukasischen Bevölkerung. Sie wird hervorgerufen durch Mutation eines Gens, welches für ein membranständiges Transportprotein kodiert, den „cystic fibrosis transmembrane conductance regulator” (CFTR). Dieser CFTR ist in der apikalen Membran von Epithelzellen lokalisiert und fungiert dort als cAMP-aktivierbarer Cl–-Kanal. Neuere Untersuchungen haben ergeben, daß der CFTR mehr als ein normaler Cl–-Kanal ist und wahrscheinlich in die Regulation einer Reihe weiterer Transportsysteme involviert ist. In dieser Studie zeigen wir, daß der CFTR in seiner Rolle als Cl–-Kanal nur eine untergeordnete Rolle in primärkultivierten menschlichen Nasenepithelzellen von CF- und Nicht-CF-Patienten spielt. Dieses Ergebnis ist besonders für das Nasenepithel von Nicht-CF-Patienten erstaunlich, da hier der CFTR korrekt eingebaut wird. In beiden Geweben spielt also eine Cl–-Sekretion verglichen mit der Na+-Absorption eine vergleichsweise geringe Rolle. Wir bestätigen mit dieser Untersuchung unsere früheren Beobachtungen, daß im menschlichen Nasenepithel Na+-Absorption der dominierende Ionentransportprozeß ist und eine Cl–-Sekretion weder in CF- noch in Nicht- CF-Geweben in relevantem Maße vorhanden ist. Zudem zeigen wir, daß weder cAMP noch ATP irgendeine Cl–-Sekretion in CF- oder Nicht-CF-Nasenepithelzellen stimulieren können. Desweiteren ergaben sich Hinweise darauf, daß sich die epithelialen Na+-Kanäle (ENaC) im Nasenepithel, welche für einen Teil der Na+-Absorption zuständig sind, von den epithelialen Na+-Kanälen in anderen Geweben unterscheiden. Diese Unterschiede zwischen den Na+-Kanälen im menschlichen Nasenepithel und den „klassischen” epithelialen Na+-Kanälen bestehen einerseits in ihrer fehlenden Aktivierbarkeit durch den intrazellulären Botenstoff cAMP und das Steroidhormon Aldosteron. Wir zeigen weiterhin, daß menschliche nasale Na+-Kanäle durch Cl–-Kanal-Blocker gehemmt werden können und eine andere Pharmakologie auf gebräuchliche Na+-Kanal-Blocker aufweisen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001060050375
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  • 2
    Electronic Resource
    Electronic Resource
    Cystic fibrosis and non-cystic-fibrosis human nasal epithelium show analogous Na+ absorption and reversible block by phenamil (1997)
    Springer
    Pflügers Archiv 434 (1997), S. 19-24 
    Details
    ISSN: 1432-2013
    Keywords: Key words Cystic fibrosis ; Human nasal epithelium ; Primary culture ; Epithelial Na+ channel ; Amiloride ; Phenamil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Transepithelial short-circuit current (I SC), potential (V T) and resistance (R T) of confluent monolayers of human nasal epithelium cultured from patients with and without cystic fibrosis (CF) were measured. In our Ussing chamber experiments with monolayers derived from non-CF and CF patients neither I SC (non-CF: 14.1 ± 1.0 μA/cm2, n = 77; CF: 16.7 ± 1.5 μA/cm2, n = 42), nor R T (non-CF: 288 ± 15 Ω· cm2; CF: 325 ± 20 Ω· cm2) showed any significant differences, only V T showed moderate but significant different values (non-CF: –3.6 ± 0.4 mV; CF: –5.6 ± 0.7 mV, respectively). Total I SC in CF cells was nearly completely inhibited by amiloride (92 ± 9.6%), while in non-CF tissue amiloride-insensitive conductances mediated a considerable amount of the I SC (36.3 ± 6.1%), indicating a lower activity of amiloride-sensitive Na+ conductances in non-CF cells. In both tissues the amiloride-sensitive I SC could also be blocked by the amiloride analogues benzamil, phenamil and 5-(N-ethyl-N-isopropyl)2’,4’-amiloride (EIPA) with different affinities. However, amiloride had a significant lower affinity in CF tissue (half-maximal blocker concentration, K 1/2 = 586 ± 59 nM) compared with non-CF tissue (K 1/2 = 294 ± 22 nM). Astonishingly, phenamil, a blocker which irreversibly blocks all epithelial Na+ channels hitherto described, inhibited the Na+ conductances of human nasal epithelium in a completely reversible way, but nevertheless with high affinity (non-CF: K 1/2 = 12.5 ± 1.2 nM; CF: K 1/2 = 17.1 ± 1.1 nM). Even in high doses none of these blockers had any effect on intracellular Ca2+ concentration as measured with Fura-2. From these findings, we conclude that the epithelial Na+ conductances of human CF nasal epithelium show modified regulation or are functionally different from those of other tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004240050358
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  • 3
    Electronic Resource
    Electronic Resource
    Electrogenic cation transport across leech caecal epithelium (1996)
    Springer
    Journal of comparative physiology 166 (1996), S. 435-442 
    Details
    ISSN: 1432-136X
    Keywords: non-selective cation channel ; leech caecum ; leaky epithelium ; leech,Hirudo medicinalis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Electrogenic cation transport across the caecal epithelium of the leechHirudo medicinalis was investigated using modified Ussing chambers. Transepithelial resistance (R T ) and potential difference (V T ) were 61.0±3.5 Ω·cm2 and-1.1±0.2 mV (n=149), respectively, indicating that leech caecal epithelium is a “leaky” epithelium. Under control conditions short circuit current (I SC ) and transepithelial Na+ transport rate (I Na ) averaged at 22.1±1.5 μA·cm-2 and 49.7±2.6 μA·cm-2, respectively. Mucosal application of amiloride (100 μmol·l-1) or benzamil (50 μmol·l-1) influenced neitherI SC norI Na . The transport system in the apical membrane showed no pronounced cation selectively and a linear dependence on mucosal Na+ concentration. Removal of mucosal Ca2+ increasedI SC by about 50% due to an increase of transepithelial Na+ transport. Trivalent cations (La3+ and Tb3+, 1 mmol·l-1 both) added to the mucosal Ringer solution reducedI Na by more than 40%. Serosal ouabain (1 mmol·l-1) almost halvedI SC andI Na while 0.1% (=54 mmol·l-1) DNP decreasedI Na to 11.8±5.1% of initial values. Serosal addition of cAMP increased bothI SC andI Na whereas the neurotransmitters FMRFamide, acetylcholine, GABA,l-dopa, serotonin and dopamine failed to show any effects; octopamine, glycine andl-glutamate reducedI Na markedly. On the basis of these results we conclude that in leech caecal epithelium apical uptake of monovalent cations is mediated by non-selective cation conductances which are sensitive to extracellular Ca2+ but insensitive to amiloride. Basolaterally Na+ is extruded via ouabain-sensitive and-insensitive ATPases. cAMP activates Na+ transport across leech caecal epithelium, although the physiological stimulus for CAMP-production remains unknown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02337888
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  • 4
    Electronic Resource
    Electronic Resource
    Electrogenic cation transport across leech caecal epithelium (1996)
    Springer
    Journal of comparative physiology 166 (1996), S. 435-442 
    Details
    ISSN: 1432-136X
    Keywords: Key words non-selective cation channel ; leechcaecum ; leaky epithelium ; leech ; Hirudo medicinalis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Electrogenic cation transport across the caecal epithelium of the leech Hirudo medicinalis was investigated using modified Ussing chambers. Transepithelial resistance (R T ) and potential difference (V T ) were 61.0±3.5 Ω ⋅ cm2 and −1.1±0.2 mV (n=149), respectively, indicating that leech caecal epithelium is a “leaky” epithelium. Under control conditions short circuit current (I SC ) and transepithelial Na+ transport rate (I Na ) averaged at 22.1±1.5 μA ⋅ cm-2 and 49.7±2.6 μA ⋅ cm-2, respectively. Mucosal application of amiloride (100 μmol ⋅ l-1) or benzamil (50 μmol ⋅ l-1) influenced neither I SC nor I Na . The transport system in the apical membrane showed no pronounced cation selectivity and a linear dependence on mucosal Na+ concentration. Removal of mucosal Ca2+ increased I SC by about 50% due to an increase of transepithelial Na+ transport. Trivalent cations (La3+ and Tb3+, 1 mmol ⋅ l-1 both) added to the mucosal Ringer solution reduced I Na by more than 40%. Serosal ouabain (1 mmol ⋅ l-1) almost halved I SC and I Na while 0.1% (=5.4 mmol ⋅ l-1) DNP decreased I Na to 11.8±5.1% of initial values. Serosal addition of cAMP increased both I SC and I Na whereas the neurotransmitters FMRFamide, acetylcholine, GABA, L-dopa, serotonin and dopamine failed to show any effects; octopamine, glycine and L-glutamate reduced I Na markedly. On the basis of these results we conclude that in leech caecal epithelium apical uptake of monovalent cations is mediated by non-selective cation conductances which are sensitive to extracellular Ca2+ but insensitive to amiloride. Basolaterally Na+ is extruded via ouabain-sensitive and -insensitive ATPases. cAMP activates Na+ transport across leech caecal epithelium, although the physiological stimulus for cAMP-production remains unknown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003600050030
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  • 5
    Electronic Resource
    Electronic Resource
    The in vitro response of thymic lymphocytes of the pig to phytohemagglutininThis work was aided by Pennsylvania Plan Funds, grant FR-00120-01 from the Division of Research Facilities and Resources, and by U.S.P.H.S. grant 5T1 Ca-5097.The work was performed at the interdisciplinary cancer research facilities of the school of veterinary medicine. (1966)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 67 (1966), S. 285-299 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The response of thymic lymphocytes of the pig to phytohemagglutinin was studied with H3 thymidine in cultures, from 0-72 hours. At the beginning of the culture period 6-18% of lymphocytes were in DNA synthesis. during the first 24 hours a sharp decrease in the number of DNA synthesizing cells was observed in both pha and control cultures, although pha cultures consistently showed small but significantly greater numbers of DNA synthesizing cells. this was followed by a definite peak in DNA synthesis and mitotic response of a minority of the cells in pha cultures between 48-54 hours, whereas in control cultures activity ceased. in addition, a small proportion of the progeny of initially DNA synthesizing medium sized lymphocytes was apparently stimulated by pha and found in mitosis by 48 hours.It was concluded that the thymus contains a fraction of lymphocytes, not in the mitotic cycle, which are capable of being transformed by pha to mitotic activity. the data also suggests some stimulation of cells already in the mitotic cycle.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1040670209
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  • 6
    Electronic Resource
    Electronic Resource
    Difference between medullary and cortical thymic lymphocytes of the pig in their response to phytohemagglutininThis work was aided by Pennsylvania Plan Funds and U.S.P.H.S. grants FR-00120-02 and 5 TI Ca 5097.Most of this work was performed at the Interdisciplinary Cancer Research Facilities of the School of Veterinary Medicine. (1966)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 68 (1966), S. 117-125 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Pig thymus tissue was cultured with organ culture techniques in the presence and absence of phytohemagglutinin in the culture medium. Morphologic and autoradiographic observations indicate that in the pig, lymphocytes capable of responding to phytohemagglutinin are located predominantly in the medulla of the thymus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1040680206
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  • 7
    Electronic Resource
    Electronic Resource
    Die Ammonolyse von (NH4)2GeF6. Darstellung und Struktur von NH4[Ge(NH3)F5] (1997)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 623 (1997), S. 1529-1534 
    Details
    ISSN: 0044-2313
    Keywords: Formation of NH4[Ge(NH3)F5] ; structure ; ammonolysis ; ir spectrum ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ammonolysis Reaction of (NH4)2GeF6. Synthesis and Structure of NH4[Ge(NH3)F5](NH4)2GeF6 reacts with ammonia to yield NH4[Ge(NH3)F5] at 280°C. The reaction path was elucidated by in situ time and temperature resolved X-ray powder diffraction. NH4[Ge(NH3)F5] crystallizes isostructurally to NH4[Si(NH3)F5] in the tetragonal space group P4/n (No. 85) with lattice constants a = 619.41(1) pm and c = 724.70(1) pm. The germanium atom is coordinated by five fluorine atoms and the nitrogen atom of the ammonia molecule. The ammonium cation is located on the Wyckoff position (2 a) in P4/n. The crystal structure is stabilized by extensive hydrogen bonding.
    Notes: (NH4)2GeF6 reagiert mit Ammoniak bei 280°C zu NH4[Ge(NH3)F5]. Der Reaktionsverlauf wurde in situ mit Hilfe der zeit- und temperaturaufgelösten Röntgenpulverdiffraktometrie verfolgt. Das so dargestellte NH4[Ge(NH3)F5] kristallisiert isostrukturell mit NH4[Si(NH3)F5] in der tetragonalen Raumgruppe P4/n (Nr. 85) mit den Gitterkonstanten a = 619,41(1) pm und c = 724,70(1) pm. Dabei ist das Germaniumatom verzerrt oktaedrisch von fünf Fluoratomen und dem Stickstoffatom des Ammoniakmoleküls koordiniert. Das Ammoniumion liegt auf der Tetraederpunktlage (2 a) in P4/n. Die Verbindung wird durch Wasserstoffbrückenbindungen stabilisiert.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19976231010
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  • 8
    Electronic Resource
    Electronic Resource
    Zur Kenntnis des Phosphorpentachlorids. Über die Reaktion von PCI5 mit aliphatischen Nitrilen (1969)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 367 (1969), S. 40-43 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The course of interactions betweens some aliphatic nitriles and PCI5 has been investigated by means of 31P—NMR spectroscopy. Phosphazo compounds are formed, and chlorination occurs. Three examples of cis-trans isomeric phosphazo compounds were found.
    Notes: Der Ablauf von Reaktionen einiger aliphatischer Nitrile mit PCI5 wurde mit Hilfe der 31P—KMR-Spektroskopie untersucht. In allen Fällen entstehen Phosphazoverbindungen; außerdem tritt Chlorierung ein. Drei Beispiele von cis-trans-isomeren Phosphazoverbindungen wurden gefunden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19693670106
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  • 9
    Electronic Resource
    Electronic Resource
    Zeit- und temperaturaufgelöste Röntgenpulverdiffraktometrie: Die Reaktion von (NH4)2SnF6 mit Ammoniak (1995)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 621 (1995), S. 617-623 
    Details
    ISSN: 0044-2313
    Keywords: Formation of Sn(NH3)2F4 ; ammonolysis ; thermal decomposition of (NH4)2SnF6 ; time and temperature resolved x-ray diffractometry ; in situ x-ray diffractometry ; solid state reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Time and Temperature Resolved in situ X-Ray Powder Diffractometry. The Reaction of (NH4)2SnF6 with AmmoniaThe thermal decomposition of (NH4)2SnF6 under an atmosphere of ammonia is reported. The complicated reaction paths were illucidated by time and temperature resolved in situ x-ray powder diffractometry. It is shown that this technique is a powerful tool to observe structural changes during reaction. It offers also a valuable access to thermodynamic and kinetic data for solid state and gas phase reactions. (NH4)2SnF6 decomposes under ammonia below room temperature to NH4F and amorphous SnF4 · x NH3. At a temperature of 80°C an intermediate product, (NH4)4SnF8, is formed, which decomposes at 140°C into (NH4)2SnF6 and NH4F. At 250°C (NH4)[Sn(NH3)F5] and Sn(NH3)2F4 are formed. The latter crystallises C-centered monoclinic with lattice constants a = 844.1(5) pm, b = 630.5(3) pm, c = 520.2(3) pm and b̃ = 114.02(7)°. At 330°C a further decomposition yields SnF2(NH2)2 with a C-centered monoclinic cell and lattice constants a = 1 069(7), b = 325.3(2), c = 504.8(3) pm and b̃ = 105.83(7)°. Finally above 500°C tin metal is formed.
    Notes: Der komplizierte Verlauf der Reaktion von NH3 mit (NH4)2SnF6 wird mit der zeit- und temperaturaufgelösten Röntgendiffraktometrie verfolgt. Dabei erweist sich diese Methode als ideale Technik, um Veränderungen in der Struktur während der Reaktion aufzuzeichnen und ebenfalls thermodynamische und kinetische Daten zu gewinnen. (NH4)2SnF6 zersetzt sich schon bei 25°C unter trockenem NH3-Gas zu NH4F und einem röntgenamorphen Ammoniakat SnF4 · x NH3. Ab 80°C bildet sich (NH4)4SnF8 als Zwischenprodukt, das sich ab 140°C wieder in (NH4)2SnF6 und NH4F zersetzt. Bei 250°C entstehen NH4[Sn(NH3)F5] und Sn(NH3)2F4. Letzteres kristallisiert monoklin C-zentriert mit den Gitterkonstanten a = 844,1(5) pm, b = 630,5(3) pm, c = 520,2(3) pm und b̃ = 114,02(7)°. Ab 330°C erhält man SnF2(NH2)2. Aus dem Pulverdiffraktogramm ergibt sich eine C-zentrierte monokline Elementarzelle mit a = 1 069(7), b = 325,3(2), c = 504,8(3) pm und b̃ = 105,83(7)°. Bei noch höheren Temperaturen erfolgt die Zersetzung zu Zinn.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19956210419
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