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  • Delayed neuronal death  (2)
  • K+ activity  (2)
  • Specific yield  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Effective porosity and specific yield of a sedimentary rock determined by a field tracing test using tritium as a tracer (1996)
    Springer
    Environmental geology 27 (1996), S. 170-177 
    Details
    ISSN: 1432-0495
    Keywords: Effective porosity ; Specific yield ; Migration ; Tracer test ; Porosity ; Tritium ; Finite element method ; Longitudinal dispersivity ; Sedimentary rock
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Effective porosity value was analyzed from the tritium concentration of sampled groundwater using a three-dimensional groundwater-flow and advection-dispersion code based on the finite element method. The effective porosity value was about 10%. Porosity values measured from core samples were 7–15%. The groundwater flow velocity estimated from the tritium concentrations was about 1 × 10−5 cm s−1. Therefore, during the low groundwater flow velocity condition, effective porosity and porosity values were the same. At the same test site, a 0.48% effective porosity value, determined by another tracer test injecting Br− solution into the aquifer during groundwater level change, was smaller than the porosity value when the flow velocity was 1.8×10−2 cm s−1. Thus the effective porosity value is concluded to be due to groundwater flow velocity. The specific yield value was calculated to be 0.6% by the total volume of tunnel seepage water and the total volume of the rock unsaturated during tunnel construction. However, as pore water continued to be drained after the groundwater level change was completed, the specific yield value became larger than 0.6%. Thus specific yield value is concluded to be due to drainage time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00770429
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Effective porosity and specific yield of a sedimentary rock determined by a field tracing test using tritium as a tracer (1996)
    Springer
    Environmental geology 27 (1996), S. 170-177 
    Details
    ISSN: 1432-0495
    Keywords: Key words Effective porosity ; Specific yield ; Migration ; Tracer test ; Porosity ; Tritium ; Finite element method ; Longitudinal dispersivity ; Sedimentary rock
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Effective porosity value was analyzed from the tritium concentration of sampled groundwater using a three-dimensional groundwater-flow and advection-dispersion code based on the finite element method. The effective porosity value was about 10%. Porosity values measured from core samples were 7–15%. The groundwater flow velocity estimated from the tritium concentrations was about 1 × 10–5 cm s–1. Therefore, during the low groundwater flow velocity condition, effective porosity and porosity values were the same. At the same test site, a 0.48% effective porosity value, determined by another tracer test injecting Br– solution into the aquifer during groundwater level change, was smaller than the porosity value when the flow velocity was 1.8 × 10–2 cm s–1. Thus the effective porosity value is concluded to be due to groundwater flow velocity. The specific yield value was calculated to be 0.6% by the total volume of tunnel seepage water and the total volume of the rock unsaturated during tunnel construction. However, as pore water continued to be drained after the groundwater level change was completed, the specific yield value became larger than 0.6%. Thus specific yield value is concluded to be due to drainage time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002540050048
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Serial imaging of bilateral striatal necrosis associated with acidaemia in adults (1996)
    Springer
    Neuroradiology 38 (1996), S. 437-440 
    Details
    ISSN: 1432-1920
    Keywords: Bilateral striatal necrosis ; Acute encephalopathy ; Delayed neuronal death ; Krebs cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Bilateral striatal necrosis in acute encephalopathy has been reported in a small number of adults with methanol or cyanide intoxication, hypoxic encephalopathy or haemolytic-uraemic syndrome. Acute encephalopathy with bilateral striatal necrosis has been reported in infants and children. However, the pathogenesis of the necrosis remains unclear. This is the first report of serial imaging from the very early to chronic stage in two acute encephalopathic adults with bilateral striatal necrosis. A clinicoradiological study is presented for clarification of the pathological process and pathogenesis. Striatal lesions were not detected in the very early stages, but only thereafter. Serial studies suggested that the lesions were caused by delayed neuronal death. These patients had severe lactic acidosis, near the limit for survival. There have been few reports of adults with acute encephalopathy and bilateral striatal necrosis in whom arterial pH was described; all these exhibited marked acidosis. The common pathophysiological condition among these encephalopathies with bilateral striatal necrosis could be lactic acidosis elicited by impairment of ATP generation through the Krebs cycle. The striatum might represent one of the target areas of Krebs-cycle blockade.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00607268
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    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Serial imaging of bilateral striatal necrosis associated with acidaemia in adults (1996)
    Springer
    Neuroradiology 38 (1996), S. 437-440 
    Details
    ISSN: 1432-1920
    Keywords: Key words Bilateral striatal necrosis ; Acute encephalopathy ; Delayed neuronal death ; Krebs cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Bilateral striatal necrosis in acute encephalopathy has been reported in a small number of adults with methanol or cyanide intoxication, hypoxic encephalopathy or haemolytic-uraemic syndrome. Acute encephalopathy with bilateral striatal necrosis has been reported in infants and children. However, the pathogenesis of the necrosis remains unclear. This is the first report of serial imaging from the very early to chronic stage in two acute encephalopathic adults with bilateral striatal necrosis. A clinicoradiological study is presented for clarification of the pathological process and pathogenesis. Striatal lesions were not detected in the very early stages, but only thereafter. Serial studies suggested that the lesions were caused by delayed neuronal death. These patients had severe lactic acidosis, near the limit for survival. There have been few reports of adults with acute encephalopathy and bilateral striatal necrosis in whom arterial pH was described; all these exhibited marked acidosis. The common pathophysiological condition among these encephalopathies with bilateral striatal necrosis could be lactic acidosis elicited by impairment of ATP generation through the Krebs cycle. The striatum might represent one of the target areas of Krebs-cycle blockade.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00607268
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Cation transport in the ampulla of the semicircular canal and in the endolymphatic sac (1987)
    Springer
    European archives of oto-rhino-laryngology and head & neck 244 (1987), S. 61-65 
    Details
    ISSN: 1434-4726
    Keywords: Na+ activity ; K+ activity ; DC potential ; Semicircular canal ; Endolymphatic sac
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We examined the effects of anoxia and ethacrynic acid on the endolymphatic potential and cation activity in the superior ampulla of the guinea pig, using double-barrelled ion-exchanger microelectrodes. In normal guinea pigs the ampullar endolymphatic potential was +3.9±1.2 mV (n=32), the Cl− activity 130±4.6 mM (n=9), and the Na+ activity 18.4±4.4 mM (n=20). After anoxia, the ampullar DC potential decreased rapidly and reversed its polarity within 5 min. It then decreased gradually for 60 min and increased afterwards to approximately zero. K+ activity decreased gradually after a latency of 10 min, whereas Na+ activity increased. During the gradual decrease of a negative ampullar endolymphatic potential, an increase in Na+ activity was observed. Thirty minutes after the intravenous injection of ethacrynic acid (100 mg/kg), the potential began to decrease, changed to a negative polarity, and approached a maximum negative level 100 min after the injection. The decrease in K+ activity corresponded to the reduction of potential whereas Na+ activity remained unchanged. The DC potential of the endolymphatic sac in normal guinea pigs was + 14.7±5.1 mV (n=17). The Na+ concentration was 103.3±14.7 mM (n=14) and the K+ concentration was 11.6 ±0.8 mM (n=4). After anoxia, the DC potential decreased rapidly and approached 0 mV within 8 min. No negative potential could be observed. The Na+ concentration began to increase 2 min after anoxia and reached the extracellular Na+ concentration about 30 min later. No significant effect of intravenous administration of ethacrynic acid (100 mg/kg) on DC potential and Na + concentration could be observed. The results suggest the presence of a different ion transport system in the endolymphatic sac from that of the cochlea and the ampullae of the semicircular canals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00453493
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    The effect of kanamycin on experimentally induced endolymphatic hydrops (1984)
    Springer
    European archives of oto-rhino-laryngology and head & neck 240 (1984), S. 63-64 
    Details
    ISSN: 1434-4726
    Keywords: Na+ activity ; K+ activity ; DC potential ; Endolymphatic hydrops ; Kanamycin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In guinea pigs with endolymphatic hydrops 6 months after operation the DC potential had decreased from +80 mV to +50 mV, while the sodium activity had increased. The twofold increase in Na+ activity could explain the increased degree of endolymphatic hydrops. The K+ activity and Cl− activity were unchanged. However, endolymphatic hydrops could be produced in kanamycin-induced deaf guinea pigs after obliteration of the endolymphatic sac and duct. The physiological data on DC potential, K+, and Na+ activity were similar to those for non-treated animals. When the animals were treated with kanamycin 6 months after the development of endolymphatic hydrops, there was no effect on the morphological and functional changes compared to controls. The data suggest that regulation of the inner ear fluid occurs independent of an intact auditory system. The effect of aminoglycoside treatment in Ménière's disease cannot be explained by an effect on endolymphatic hydrops formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00464346
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    Paper (German National Licenses)
    Fulltext
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