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  • 1
    Digitale Medien
    Digitale Medien
    Characterization of Ryanodine-sensitive Ca2+ Release from Microsomal Vesicles of Rat Parotid Acinar Cells: Regulation by Cyclic ADP-ribose (1997)
    Springer
    The journal of membrane biology 156 (1997), S. 231 -239 
    Details
    ISSN: 1432-1424
    Schlagwort(e): Key words:45Ca2+ efflux — Caffeine — Ruthenium red — Heparin — Endoplasmic reticulum — Thapsigargin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract. We have measured ryanodine (caffeine)-sensitive 45Ca2+ release from isolated microsomal vesicles of endoplasmic reticulum prepared from rat parotid acinar cells. After a steady state of ATP-dependent 45Ca2+ uptake, the addition of caffeine (40 mm), ryanodine (10∼500 μm) or an NAD+ metabolite, cyclic ADP-ribose (cADPR, 4 μm) released about 10% of the 45Ca2+ that had been taken up. The 45Ca2+ release was not inhibited by heparin, an antagonist of IP3 receptor. The effects of caffeine, ryanodine and cADPR on 45Ca2+ release were also tested in the presence of thapsigargin (TG), an inhibitor of microsomal Ca2+-ATPase. When caffeine (10∼40 mm), ryanodine (10 μm) or cADPR (1∼10 μm) was added in the medium with 100 nm TG, a significant 45Ca2+ release was seen, while higher concentrations of ryanodine (〉100 μm) did not cause any 45Ca2+ release in the presence of TG. The initial rate of caffeine (40 mm)-induced 45Ca2+ release was increased by a pretreatment with 10 μm ryanodine, whereas the caffeine-induced 45Ca2+ release was strongly inhibited by the presence of a higher concentration (500 μm) of ryanodine. cADPR-induced 45Ca2+ release was also inhibited by 500 μm ryanodine. Caffeine (40 mm)- or cADPR (4 μm)-induced 45Ca2+ release was abolished by a presence of ruthenium red (50∼100 μm). The presence of a low concentration (0.5 μm) of cADPR shifted the dose-response curve of caffeine-induced 45Ca2+ release to the left. These results indicate the presence of a ryanodine sensitive Ca2+ release mechanism in the endoplasmic reticulum of rat parotid acinar cells that is distinct from the IP3-sensitive Ca2+ channel and is activated by caffeine, cADPR and a low concentration (10 μm) of ryanodine, but is inhibited by higher concentrations (〉100 μm) of ryanodine and ruthenium red. The properties of the ryanodine-sensitive mechanism are similar to that of the ryanodine receptor as described in muscle cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002329900203
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Intracellular pH regulation in the mouse lacrimal gland acinar cells (1988)
    Springer
    The journal of membrane biology 101 (1988), S. 73-81 
    Details
    ISSN: 1432-1424
    Schlagwort(e): intracellualr pH ; lacrimal gland ; amiloride ; DIDS ; Na+/H+ antiport ; Cl−/HCO 3 − ; antiport
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Summary Intracellular pH (pH i ) of the acinar cells of the isolated, superfused mouse lacrimal gland has been measured using pH-sensitive microelectrodes. Under nonstimulated condition pH i was 7.25, which was about 0.5 unit higher than the equilibrium pH. Alterations of the external pH by ±0.4 unit shifted pH i only by ±0.08 unit. The intracellular buffering value determined by applications of 25mm NH 4 + and bicarbonate buffer solution gassed with 5% CO2/95% O2 was 26 and 46mm/pH, respectively Stimulation with 1 μm acetylcholine (ACh) caused a transient, small decrease and then a sustained increase in pH i . In the presence of amiloride (0.1mm) or the absence of Na+, application of ACh caused a significant decrease in pH i and removal of amiloride or replacement with Na+-containing saline, respectively, rapidly increased the pH i . Pretreatment with DIDS (0.2mm) did not change the pH i of the nonstimulated conditions; however, it significantly enhanced the increase in pH i induced by ACh. The present results showed that (i) there is an active acid extrusion mechanism that is stimulated by ACh; (ii) stimulation with ACh enhances the rate of acid production in the acinar cells; and (iii) the acid extrusion mechanism is inhibited by amiloride addition to and Na+ removal from the bath solution. We suggest that both Na+/H+ and HCO 3 − /Cl− exchange transport mechanisms are taking roles in the intracellular pH regulation in the lacrimal gland acinar cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01872822
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Characterization of two different Ca2+ uptake and IP3-sensitive Ca2+ release mechanisms in microsomal Ca2+ pools of rat pancreatic acinar cells (1995)
    Springer
    The journal of membrane biology 144 (1995), S. 111-120 
    Details
    ISSN: 1432-1424
    Schlagwort(e): Thapsigargin ; Vanadate ; Ca2+ pump ; Ca2+ ATPase ; SERCA ; Endoplasmic reticulum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract We have examined the effect of the Ca2+ (Mg2+)-ATPase inhibitors thapsigargin (TG) and vanadate on ATP-dependent 45Ca2+ uptake into IP3-sensitive Ca2+ pools in isolated microsomes from rat pancreatic acinar cells. The inhibitory effect of TG was biphasic. About 40–50% of total Ca2+ uptake was inhibited by TG up to 10 nm (apparent Ki≈4.2 nm, Ca2+ pool I). An additional increase of inhibition up to 85–90% of total Ca2+ uptake could be achieved at 15 to 20 nm of TG (apparent Ki≈12.1 nm, Ca2+ pool II). The rest was due to TG-insensitive contaminating plasma membranes and could be inhibited by vanadate (apparent Ki≈10 μm). In the absence of TG, increasing concentrations of vanadate also showed two phases of inhibition of microsomal Ca2+ uptake. About 30–40% of total Ca2+ uptake was inhibited by 100 μm of vanadate (apparent Ki≈18 μm, Ca2+ pool II). The remaining 60–70% could be inhibited either by vanadate at concentrations up to 1 mm (apparent Ki≈300 μm) or by TG up to 10 nm (Ca2+ pool I). The amount of IP3-induced Ca2+ release was constant at ≈25% over a wide range of Ca2+ filling. About 10–20% remained unreleasable by IP3. Reduction of IP3 releasable Ca2+ in the presence of inhibitors showed similar dose-response curves as Ca2+ uptake (apparent Ki≈ 3.0 nm for IP3-induced Ca2+ release as compared to ≈4.2 nm for Ca2+ uptake at TG up to 10 nm) indicating that the highly TG-sensitive Ca2+ pump fills the IP3-sensitive Ca2+ pool I. At TG concentrations 〉10 nm which blocked Ca2+ pool II the apparent Ki values were ≈11.3 and ≈12.1 nm, respectively. For inhibition by vanadate up to 100 μm the apparent Ki values were ≈18 μm for Ca2+ uptake and ≈7 μm for Ca2+ release (Ca2+ pool II). At vanadate concentrations up to 1 mm the apparent Ki values were ≈300 and ≈200 μm, respectively (Ca2+ pool I). Both Ca2+ pools I and II also showed different sensitivities to IP3. Dose-response curves for IP3 in the absence of inhibitors (control) showed an apparent Km value for IP3 at 0.6 μm. In the presence of TG (inhibition of Ca2+ pool I) the curve was shifted to the left with an apparent Km for IP3 at 0.08 μm. In the presence of vanadate (inhibition of Ca2+ pool II), the apparent Km for IP3 was 2.1 μm. These data allow the conclusion that there are at least three different Ca2+ uptake mechanisms present in pancreatic acinar cells: TG- and IP3 insensitive but highly vanadate-sensitive Ca2+ uptake occurs into membrane vesicles derived from plasma membranes. Two Ca2+ pools with different TG-, vanadate- and IP3-sensitivities are most likely located in the endoplasmic reticulum at different cell sites, which could have functional implications for hormonal stimulation of pancreatic acinar cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00232797
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    The effect of renal hydrodynamics on immune complex deposition (1976)
    Springer
    Cellular and molecular life sciences 32 (1976), S. 933-934 
    Details
    ISSN: 1420-9071
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The role of renal hydrodynamics on renal deposition of immune complexes was evaluated in acute serum sickness. Using i.v. radiolabelled antigen in rabbits under a variety of hydrodynamic alterations, these studies suggested that although intrarenal hydrodynamics influence renal deposition of immune complexes factors other than intrarenal hydrostatic pressure may be important.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02003776
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  • 5
    Digitale Medien
    Digitale Medien
    Anti-oxidative effect of coenzyme Q10 (1980)
    Springer
    Cellular and molecular life sciences 36 (1980), S. 1002-1003 
    Details
    ISSN: 1420-9071
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Coenzyme Q10 is effective as an anti-oxidant like α-tocopherol, especially in the heart.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01953847
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    The potency of heparin-like activity of glycosaminoglycans released by human endothelial cells in culture (1985)
    Springer
    Cellular and molecular life sciences 41 (1985), S. 671-673 
    Details
    ISSN: 1420-9071
    Schlagwort(e): Endothelial cells ; glycosaminoglycan ; heparin, smooth muscle cells
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Glycosaminoglycans isolated from culture medium conditioned by human endothelial cells showed heparin-like antithrombin III cofactor activity measured by Xa inhibition. Their activity was relatively weak, 0.1% of the potency of heparin, but was approximately 5-fold more potent than that of glycosaminoglycans derived from vascular smooth muscle cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02007713
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Expression of the mutant gene for L-gulono-γ-lactone oxidase in scurvy-prone rats (1989)
    Springer
    Cellular and molecular life sciences 45 (1989), S. 126-129 
    Details
    ISSN: 1420-9071
    Schlagwort(e): L-gulono-γ-lactone oxidase ; ascorbic acid deficiency ; enzyme defect ; rat ; nuclei acid hybridization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A mutant strain of Wistar rats with L-gulono-γ-lactone oxidase deficiency has recently been established. To investigate this deficiency by DNA and RNA blot hybridization analyses, a fragment of a previously cloned cDNA encoding rat L-gulono-γ-lactone oxidase was used as a probe. When genomic DNA of the mutant rat was digested with several restriction enzymes, the probe hybridized to fragments of the same sizes as those produced from DNA of normal rats. Poly(A)+RNA from the liver of the mutant rat was found to contain an L-gulono-γ-lactone oxidase-specific mRNA of a normal size at a comparable level to that of normal rats. An in vitro translation experiment revealed that the mRNA programmed the synthesis of an enzyme protein which had the same molecular weight as that of the translational product of the normal mRNA, although the amount synthesized was markedly reduced as compared with that synthesized with the normal mRNA. In accordance with this observation, a very low but definite degree of L-gulono-γ-lactone oxidase activity was detected in the microsomes of the mutant rat by a newly developed, highly sensitive method.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01954844
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  • 8
    Digitale Medien
    Digitale Medien
    Long range scattering for non-linear Schrödinger and Hartree equations in space dimensionn≥2 (1993)
    Springer
    Communications in mathematical physics 151 (1993), S. 619-645 
    Details
    ISSN: 1432-0916
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik , Physik
    Notizen: Abstract We consider the scattering problem for the non-linear Schrödinger (NLS) equation with a power interaction with critical powerp=1+2/n in space dimensionsn=2 and 3 and for the Hartree equation with potential |x|−1 in space dimensionn≥2. We prove the existence of modified wave operators in theL 2 sense on a dense set of small and sufficiently regular asymptotic states.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02097031
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  • 9
    Digitale Medien
    Digitale Medien
    A Theoretical Approach to Temperature Modulated Power Compensation DSC (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 691-697 
    Details
    ISSN: 1572-8943
    Schlagwort(e): heat capacity measurement ; power compensation DSC ; steady state ; temperature modulated DSC ; temperature modulated power compensation DSC
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The steady state of temperature modulated power compensation DSC has been theoretically investigated for measurements of complex heat capacity, taking accounts of heat capacities of heat paths, heat loss to the environment, and mutual heat exchange between the sample and the reference material. Thermal contact between the sample cell and the cell holder is also taken into accounts. Rigorous and general solutions are obtained. From these solutions application of the technique to heat capacity measurements is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010189602874
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  • 10
    Digitale Medien
    Digitale Medien
    A modified method for kinetic analysis of thermoanalytical data (1976)
    Springer
    Journal of thermal analysis and calorimetry 9 (1976), S. 369-373 
    Details
    ISSN: 1572-8943
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Résumé La méthode précédemment proposée par l'auteur est modifiée. La nouvelle méthode qui est présentée transforme les données thermoanalytiques en données isothermes équivalentes et utilise des relations linéaires pour établir le mécanisme et le facteur pré-exponentiel au lieu de la méthode antérieure avec ajustement des courbes. Les avantages de cette nouvelle méthode sont illustrés en l'appliquant à la décomposition du polycaprolactane.
    Kurzfassung: Zusammenfassung Es wurde eine neue Methode durch Modifizierung der früheren Methode des Autors entwickelt. Bei der neuen Methode werden die thermoanalytischen Daten in isotherme umgewandelt und anstatt der Kurven-Anpassung der vorhergehenden Methode werden lineare Zusammenhänge zur Klärung des Mechanismus und des pre-exponentiellen Faktors eingesetzt. Die Vorteile der neuen Methode werden durch ihre Anwendung bei der Untersuchung der Zersetzung von Polycaprolactan veranschaulicht.
    Notizen: Abstract A method is devised by modification of the author's previous method. Thermoanalytical data are transformed to equivalent isothermal ones, and linear relations are utilized to elucidate the mechanism and the pre-exponential factor, instead of curvefitting. Advantages are illustrated by applying this method to the decomposition of polycaprolactam.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01909401
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