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  • Articles: DFG German National Licenses  (3)
  • PTFE  (1)
  • SSRE  (1)
  • [Ca2+]i and [Ca2+]n  (1)
  • 1
    ISSN: 1436-2813
    Keywords: pseudointimal hyperplasia ; fibril length ; PTFE ; animal model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In addition to the polytetrafluoroethylene (PTFE) vascular graft (G) with its conventionally smooth surface, a unique PTFE graft with a ridged outer wall (T) is now also currently available for clinical use. Although an excellent antikinking property is provided by this unique outer structure, the possible influence of the structure on the formation of pseudointima has not yet been investigated in detail. Four kinds of T grafts (3 mm inner diameter, 3 cm long) with various fibril lengths (FL, T-15, T-30, T-60, T-90) and a G graft with 30 μm FL (G-30) were implanted into the inferior vena cava of rabbits. The patency of the grafts at 4 weeks were as follows: 6/8(T-15), 6/8(T-30), 5/8(T-60), 0/8(T-90) and 4/6 (G-30). Pseudointimal hyperplasia (PH) of the T grafts advanced as the FL increased, judging by the thickness of the pseudointima, cellular density, and maturity of fibroblasts. In addition, the maturity of endothelial-like cells on the luminal surface increased as the FL increased. The degree of pseudomintimal hyperplasia in G-30 was comparable to that of T-15, although the maturity of the endothelial-like cells was similar to that of T-60. Microscopically, there was a microheterogeneity of cellular density in T grafts probably due to the uneven outer structure. In conclusion, not only FL but also the outer structure of PTFE may thus influence the formation of the pseudointima.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0730-2312
    Keywords: [Ca2+]i and [Ca2+]n ; Ca2+ gradients ; confocal laser scanning microscopy ; Fluo-3 ; heterogeneity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Ca2+ concentration inside human umbilical vein endothelial cells was studied separately in cytosol and nucleus by a confocal laser scanning microscopy using fluo-3. The in vivo calibration curve for cytosol and nucleus showed good linearity between fluorescence intensity and Ca2+ concentration in cytosol ([Ca2+]i) and nuclei ([Ca2+]n). After calibration, [Ca2+]n was constantly higher than [Ca2+]i before and after the chelation of extracellular Ca2+ suggesting an active Ca2+ accumulation system on nuclear membrane. [Ca2+]n was also constantly higher than [Ca2+]i after the stimulation of thrombin (0.05 U/ml), FCS (10%), and thapsigargin (Tsg, 1μM). The temporal change of [Ca2+]n and [Ca2+]i was identical, and [Ca2+]i gradient towards the nucleus and peripheral or central [Ca2+]n rise was observed after these stimulations. From these results, [Ca2+]n is not only regulated by the active Ca2+ accumulation system on nuclear membrane at rest but also the generation of Inositol-triphosphate. FCS caused heterogeneous [Ca2+]n or [Ca2+]i rise from cell to cell; single spike or oscillatory change of [Ca2+]n and [Ca2+]i was observed in about 56% of cells, which were completely abolished by the chelation of extracellular Ca2+, suggesting that FCS stimulated [Ca2+]n and [Ca2+]i rise solely depending on Ca2+ influx from extracellular medium. The higher concentration of [Ca2+]n and heterogeneous [Ca2+]n rise may have important roles in nuclear-specific cellular responses. © 1996 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0730-2312
    Keywords: fluid shear stress ; adrenomedullin ; endothelial cell ; SSRE ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Vascular endothelial cells are potent modulators of vascular tone in response to shear stress. Levels of vasoactive peptides such as adrenomedullin (AM), endothelin-1 (ET-1), C-type natriuretic peptide (CNP), and nitric oxide (NO) are affected by fluid shear stress. AM, a potent vasodilator and suppressor of smooth muscle cell proliferation, contains the shear stress responsive element (SSRE) “GAGACC” in its promoter region. To examine the role of AM in the shear stress response, cultured human aortic endothelial cells (HAoECs) were exposed to fluid shear stresses of 12 and 24 dynes/cm2 in a cone-plate shear stress loading apparatus for various time periods, and the levels of AM gene expression and peptide secretion from HAoECs were measured by Northern blotting analysis and radioimmunoassay (RIA), respectively. Both AM gene transcription and AM peptide levels were down-regulated by fluid shear stress in a time- and magnitude-dependent manner. Our results demonstrate that the normal level of arterial shear stress down-regulates AM expression in HAoECs, suggesting that AM participates in the modulation of vascular tone by fluid shear stress. J. Cell. Biochem. 71:109-115, 1998. © 1998 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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