H. Yamada

Kagoshima University, Kagoshima-shi, Kagoshima-ken, Japan

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Publications (4)15.92 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The effects of ligustrazine on hepatic oxygenation in the isolated rat liver were investigated during prolonged perfusion and following the injection of norepinephrine. After injection of erythrocytes into the perfusate, the hemoglobin spectra in the liver were measured by Erlangen microlightguide spectroscopy, and the hemoglobin oxygenation (HbO2) in the liver was calculated on the basis of the Kubelka-Munk theory. During artificial perfusion, the HbO2 value was decreased from 59.3 +/- 6.4% (after one hour's perfusion) to 25.5 +/- 19.5% (n = 441; after six hours' perfusion). However, when ligustrazine was injected into the perfusate after six hours' perfusion, the HbO2 values recovered to 56.4 +/- 9.7% (n = 441). After injection of norepinephrine, HbO2 in the liver decreased from 48.8 +/- 10.4% to 25.2 +/- 18.4% (n = 961), while subsequent administration of ligustrazine caused a recovery to 62.9 +/- 6.0% (n = 961). Our results suggested that ligustrazine is a powerful hepatic vasodilator for improving hepatic oxygenation.
    In vivo (Athens, Greece) 01/1999; 13(1):29-34. · 1.15 Impact Factor
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    ABSTRACT: To evaluate microvascular regulation in human skin, changes in intracapillary hemoglobin oxygen saturation (HbO2) were studied in human finger skin following an abrupt change in local ambient temperature. In the first series of experiments, we assessed the heterogeneity of HbO2 in the skin by using a 2-D scanning system and a rapid micro-lightguide spectrophotometer at each of two near-normal skin temperatures. The data showed that heterogeneous oxygenation exists in human skin even at near-normal temperatures (although the pattern is different at different skin temperatures). In a second series of experiments, the performance of the microcirculation of the skin was continuously examined in a selected area with initially different oxygenation levels during an abrupt change in local ambient temperature (5, 15, 25, 35, and 45 degrees C). At very low (5 degrees C) or very high (45 degrees C) temperatures, oxygenation in tissues within the low HbO2 area increased greatly, but there was no such change within the high HbO2 area. Our data indicate that different types of capillary supply units exist in human skin (indicated by the initially different oxygenation levels). These different capillary supply units may operate to produce a local redistribution of flow between the various capillary supply units. This effect may be initiated by heat sensors and oxygen sensors when temperature of the skin is varied.
    Microvascular Research 10/1998; 56(2):104-12. DOI:10.1006/mvre.1998.2097 · 2.43 Impact Factor
  • Anesthesiology 01/1998; 89(Supplement):321A. DOI:10.1097/00000542-199809070-00013 · 6.17 Impact Factor
  • Anesthesiology 01/1998; 89. DOI:10.1097/00000542-199809120-00048 · 6.17 Impact Factor

Publication Stats

10 Citations
15.92 Total Impact Points

Institutions

  • 1998–1999
    • Kagoshima University
      • Department of Anesthesiology and Critical Care Medicine
      Kagoshima-shi, Kagoshima-ken, Japan