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  • Coronary artery disease  (1)
  • Donna  (1)
  • Springer  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Auxin-induced growth and its linkage to potassium channels (1997)
    Springer
    Planta 201 (1997), S. 227-234 
    Details
    ISSN: 1432-2048
    Keywords: Auxin-induced growth ; Channel blocker ; Donna ; Potassium channel ; Tetraethylammonium ; Zea (auxin-induced growth)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We investigated the potassium dependence of rapid auxin-induced growth of scrubbed maize (Zea mays L. cv. Garant) coleoptile segments by means of positional angular transducers. Our setup permitted six simultaneous high-resolution measurements. Provided a buffer with a high concentration of calcium was used in conjunction with well-abraded coleoptiles, (i) there was no auxin-induced growth in the absence of K+ions, whereas in the presence of 1–10 mM KCl auxin-induced growth could be detected after a lag phase of 20 min; (ii) auxin-pretreated plants, which were not growing in the absence of K+ions displayed an instantaneous growth burst if 1–10 mM KCl was added; (iii) this burst of growth did not occur in the absence of auxin, excluding the possibility that it was due to “stored” endogenous growth and (iv) it could not be triggered by Cl-, confirming that it was not an anion effect. The effect was. specific for monovalent cations and showed an apparent selectivity for K+ and Rb+, but was not observed with Li+ or Na+. The action of 1 mM K+ was reversibly blocked by 10–30 mM tetraethylammonium (TEA) and 5 mM Ba2+. Measurements of auxin-induced proton secretion using a computer-controlled pH-stat revealed a similar dependency on the ionic composition of the bathing medium and a similar inhibition by TEA. We suggest that both auxin-induced growth and proton secretion strictly depend on extracellular K+ions and the uptake of K+ mediated by K+ channels at the plasma membrane. These results generally support the acid-growth theory of auxin action, and also concur with evidence that auxin modulation of K+ channels plays a role in the signalling cascade leading to auxin-induced cell elongation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01007708
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Catheter associated problems of multi-fibre systems in clinical excimer laser angioplasty (1990)
    Springer
    Lasers in medical science 5 (1990), S. 351-356 
    Details
    ISSN: 1435-604X
    Keywords: Arteries ; Laser angioplasty ; Transluminal angioplasty ; Heart ; Coronary artery disease ; Lasers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract We report our experience in 60 patients using a recently designed 4 French ring catheter system for coronary and a 7 French ring catheter for peripheral percutaneous excimer laser angioplasty. The advantages in comparison to bare fibres comprise an improved flexibility and a central channel for insertion of guide wires to minimize the risk of mechanical vessel wall perforation. The peripheral laser catheter initially transmitted overall energies of 20 mJ pulse−1 (51 mJ pulse−1 mm−2), the coronary device 4.5–5 mJ pulse−1 (32 mJ pulse−1 mm−2). A 50% or more decrease of energy transmission was found in 43% of coronary catheters due to a number of blinded fibres with other fibres remaining intact. This was either due to a retrograde expansion of shock waves generated by the excimer pulse at a calcified lesion, or the result of a deleterious back-reflection of the laser light by contrast media. However, using both laser catheters ablation of plaque in vivo proved to be possible. Small mechanical defects of the catheter tips in 27% did not result in patient related complications. Our initial experience favours further improvement of ring catheters for percutaneous excimer laser angioplasty.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02032591
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