著者

李 鍾酷

出版者

日本医科大学医学会

雑誌

日本医科大学雑誌 (ISSN:00480444)

巻号頁・発行日

vol.26, no.11, pp.1173-1185, 1959-11-15 (Released:2010-10-14)

参考文献数

75

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Experiments have been done on the vital reactions in acute and chronic exposure to the lowered barometric pressure using rabbits and high altitude chamber, and new approaches were undertaken for the elucidation of the mechanism of altitude adaptation from the analyses of blood viscosity and plasma proteins using 8 female rabbits exposed to 18, 000 feet for nine weeks.Those findings in acute and chronic hypoxci hypoxia were sammarized in Table 21. Shortly speaking, in acute hypoxia the organism can reveal its homeostatic mechanism through only physical method (i.e. hyperpnea), and on the contrary, for biological or chemical adaptation, it takes considerable time.Hypoxic respiratory acidosis is different from normoxic respiratory acidosis in its reduced CO2-combining capacity.In chronic hypoxia, namely, acclimatization to 18, 000 feet for nine weeks, hemoglobin concentration, hematocrit, circulating blood volume, circu lating plasma volume, and cell volume increased 20, 23, 78, 36 and 116%, respectively. Plasma protein amount increased about 33 Albumin-globulin ratio was elevated, but serum γ-globulin decreased.In short, the vital responses in acclimatization to hypoxia is the increase of oxygen carrying capacity due to increased circulating hemoglobin. This increase was accomplished by the increase of erythrocytes. However, when hematocrit increa ses over 60%, blood viscosity becomes very high and consequently circulatory disturbances result. The organism prevents increase in hematocrit by increasing circulating blood volume to minimize such disturbances. In reality, the circulating hemoglobin amount increased to twice normal. In order to prevent high hematocrit, plasma volume also increased. To compensate for increased blood viscosity due to somewhat increased hematocrit, plasma viscosity was lowered by decreased plasma protein concentration and higher albumin-globulin ratio. Moreover, nutritional disturbances and the plasma colloid osmotic pressure functions were completely compensated by increased total circulating plasma protein amount and by relative increase of the albumin fraction.Reasonable and physiologic compensatory vital functions of the organism were shown in these phenomena exhibited by the acclimatized animals.