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  • 1
    Electronic Resource
    Electronic Resource
    Time averaging by means of a computer controlled dye-laser spectrometer (1980)
    Springer
    Applied physics 22 (1980), S. 361-364 
    Details
    ISSN: 1432-0630
    Keywords: 07.65 ; 42.80 ; 42.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The noise characteristic of available laser sources limits the sensitivity of saturated absorption spectroscopy. Time averaging is one method to improve the signal-to-noise ratio. A computer controlled dye-laser spectrometer is described which has the capability to scan several times any selected frequency range with an absolute accuracy of ±200 kHz. The sensitivity of this system is demonstrated by measuring the isotope shift of the low abundant38Ar and by detecting a weak83Kr-hyperfine component.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00901057
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of organochlorine pesticides on DNA synthesis of cultured oviductal and uterine cells and on estrogen receptor of uterine tissue from heifers (1996)
    Springer
    Archives of toxicology 70 (1996), S. 490-496 
    Details
    ISSN: 1432-0738
    Keywords: Key words Organochlorine pesticides ; Cultured oviductal and uterine cells ; DNA synthesis ; Estrogen receptor ; Bovine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The pesticides DDT, MXC and γHCH at concentrations between 41 and 200 μM inhibited DNA synthesis (measured by [3H]thymidine incorporation) of cultured bovine oviductal endosalpingeal and uterine cells in the order DDT〉MXC〉γHCH, in comparison to nonexposed controls. Sensitivity to the toxicants was greater in uterine epithelial and stromal cells than in uterine smooth muscle or oviductal endosalpingeal cells. Besides the inhibitory effect, there was a stimulatory effect on DNA synthesis in epithelial cells in the range of 28 nM to 2.8 μM DDT and in stromal cells at 2.8 and 28 nM for MXC. An explanation for this reaction could be that both toxicants have an estrogen-like effect. In the present study, it is shown that the o,p’ isomer of DDT can bind to the cytoplasmatic estrogen receptor and DDT or MXC were able to inhibit the binding of radiolabelled estradiol to the uterine endometrial explants in bovine, whereas γHCH did not change the binding. These findings represent an estrogenic effect of DDT and MXC in two complete in vitro systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002040050303
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  • 3
    Electronic Resource
    Electronic Resource
    A comparative study on proliferation, macromolecular synthesis and energy metabolism of in vitro-grown ehrlich ascites tumor cells in the presence of glucosone, galactosone and methylglyoxal (1984)
    Springer
    Journal of cancer research and clinical oncology 107 (1984), S. 206-210 
    Details
    ISSN: 1432-1335
    Keywords: Ehrlich ascites tumor cells ; Methylglyoxal ; Glucosone ; Galactosone ; Growth inhibition ; DNA synthesis ; Protein Synthesis ; Energy Metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Proliferation of in vitro grown Ehrlich ascites tumor cells is completely inhibited by 0.2–0.4 mM methylglyoxal and 1–2mM glucosone or galactosone without severely affecting viability (dye exclusion test); no phase-specific arrest of cell growth is observed. 2. Incorporation of [14C] thymidine into the acid-insoluble fraction of the cells decreases within a few minutes to less than 50% of that in controls in the presence of 0.4 mM methylglyoxal, and 2 mM glucosone or galactosone causes a comparable inhibition of DNA synthesis after 2 h or 4 h, respectively. 3. The action of 0.4 mM methylglyoxal inhibits incorporation of [14C] leucine within a few minutes by more than 70%, while 2 mM glucosone and galactosone are significantly less effective (50%–60% inhibition after 12 h). 4. While methylglyoxal and galactosone do not severely affect lactate production of the cells, 2 mM glucosone reduces glycolysis by 60%–70%; ATP/ADP ratios did not fall below 3.5 in the presence of the inhibitors (controls 4–6). 5. It is suggested that the reaction potentialities of the oxaldehyde function of the inhibitors play an important role in their growth-inhibitory acitivity, besides exerting a specific effect on hexokinase (glucosone) and UTP-trapping activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01032608
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  • 4
    Electronic Resource
    Electronic Resource
    Conformational changes of Na,K-ATPase probed with eosin Y (1996)
    Springer
    Journal of fluorescence 6 (1996), S. 165-168 
    Details
    ISSN: 1573-4994
    Keywords: Cation binding ; fluorescence decay ; kinetics ; binding constants ; Na,K-ATPase ; eosin Y
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Time-resolved fluorescence and binding studies have been carried out on Na,K-ATPase in the presence of the fluorescent dye eosin Y to obtain thermodynamic and kinetic parameters for the interaction of the enzyme with different cations. Eosin Y binding is indicated by a 3 ns fluorescence decay process and is observed only in the presence of mono- and divalent cations. This type of cation binding is interpreted as a nonselective electrostatic interaction, with negatively charged groups of the enzyme providing a high-affinity eosin Y binding site. Eosin Y binding is observed only under conditions where the enzyme exists in the conformational state F1. The kinetic parameters of eosin Y binding have been determined employing stopped-flow fluorometry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00732056
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  • 5
    Electronic Resource
    Electronic Resource
    DEDO: A specific, fluorescent inhibitor for spectroscopic investigations of Na,K-ATPase (1994)
    Springer
    Journal of fluorescence 4 (1994), S. 287-290 
    Details
    ISSN: 1573-4994
    Keywords: Na,K-ATPase ; fluorescent inhibitor ; kinetics ; energy transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The interaction between the fluorescent ouabain derivative DEDO and purified renal Na,K-ATPase (isolated from different animal species) is investigated. Equilibrium binding studies provide a pK value of about 7.5 and a stoichoimetric coefficient of 1. Nonmodified ouabain exhibits the same affinity to the rabbit enzyme; the enzyme originating from the other sources binds DEDO 10 times less strongly than ouabain. Kinetic studies indicate that this is the consequence of a 10 times higher dissociation rate constant of the complexes formed with DEDO. The fluorescence emission intensity of DEDO is enhanced, being dependent on the enzyme source. The single decay time of DEDO is 3 ns in the absence and 21 ns in the presence of the rabbit enzyme and 14 ns in the presence of the pig renal enzyme. This result suggests that the fluorophore of DEDO is bound to a very hydrophobic environment of the enzyme. Further characterization of the static fluorescence spectra provides evidence for energy transfer between Trp residues of the enzyme and DEDO. Distance estimations suggest that one or two Trp residues are likely to be located in the proximity of the fluorophore.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01881441
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    Paper (German National Licenses)
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