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  • Articles: DFG German National Licenses  (2)
  • 2000-2004  (2)
  • Key words Skin tissue oxygen saturation  (1)
  • Senescence  (1)
  • Nicotiana tabacum
  • white clover
  • 1
    ISSN: 1432-1254
    Keywords: Key words Skin tissue oxygen saturation ; Total hemoglobin ; Near-infrared spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract  The oxygen saturation (StO2) and total hemoglobin volume in cutaneous blood are closely related to cutaneous metabolism and are important factors in determining the skin color. Most conventional apparatuses for the measurement of cutaneous metabolism have been designed to evaluate qualitative changes in the oxyhemoglobin volume, deoxyhemoglobin volume, and their sum (total Hb volume) relative to their baseline values. In this study, we developed an instrument for non-invasive evaluation of individual and regional differences in StO2 and Hb volume, a system unaffected by melanin (Kao PSA system model III), and examined the validity of its application. First, changes in StO2 and total Hb volume in the antebrachial region during venous occlusion and devascularization by compression of the brachial region were evaluated. Changes in total Hb volume following venous occlusion were found to reflect the cutaneous blood flow. Also, StO2 was considered to reflect the state of oxygen consumption by the skin, because it was markedly reduced during devascularization. Next, the subjects were exposed to graded hypobaric conditions, and the relationships among StO2, arterial blood oxygen saturation (SaO2), and venous blood oxygen saturation (SvO2) were studied. StO2 showed significant positive correlations with SaO2 (r=0.811, P〈0.001) and SvO2 (r=0.966, P〈0.001), and its correlation with SvO2 was particularly strong. Therefore, StO2 was found to be closely dependent on SvO2. Lastly, StO2, total Hb volume, and other parameters were measured in healthy women (aged 20–69 years), and their regional differences and age- associated changes were evaluated. These regional differences (angle of mouth 〉 cheek 〉 forehead) and age-associated decreases in StO2 are considered to be caused by the age-associated decreases in the cutaneous blood flow.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Protoplasma 214 (2000), S. 180-193 
    ISSN: 1615-6102
    Keywords: Amyloplast ; Coleoptile ; Development ; Mitochondrion ; Oryza sativa ; Senescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The coleoptile of rice (Oryza sativa L. cv. Nippon-bare) emerges from the imbibed seed on day 2 after sowing and ceases its growth on day 3. In cross section, the cells near the outer epidermis turn into green between days 2 and 3, while those near the inner epidermis remain colorless. In this study, the complete process of the development in the nongreening cells in the coleoptile was examined by fluorescence and electron microscopy. Embryonic morphology on day 0 was rapidly converted into the differentiated greening or nongreening cells between days 1 and 2. Senescence in the inner, nongreening region first appeared on day 4 in the third or fourth cell layer from the inner epidermis and then spread towards both the inner and the outer epidermis, and the inner cells collapsed completely before the outer cells senesced. Cells adjacent to the inner epidermis, which senesced slowly, followed a sequence of events during development: (1) degradation of plastid DNA; (2) dispersal of nuclear chromatin, differentiation of plastids into amyloplasts, degradation of mitochondrial DNA; (3) degradation of the starch in amyloplasts; (4) disorganization of plastids; (5) condensation of the nucleus, shrinkage of mitochondria; (6) complete loss of cellular components, distortion of cell walls. In the interior cells, the early events including degeneration of plastid DNA and mitochondrial DNA occurred in parallel with those in the cells adjacent to the inner epidermis, yet rapid collapse of all the cellular components proceeded between days 3 and 5, and nuclear condensation could not be detected.
    Type of Medium: Electronic Resource
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