| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1999: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1998: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
The purpose of this study is to establish the carbon dioxide (COィイD22ィエD2) toxicity, make clear the toxicological effects and the toxic mechanisms. (1) The lethal dose of 50% (LDィイD250ィエD2) in mouse [METHODS] Mice were exposure at any COィイD22ィエD2 concentration in the grass chamber for ten minutes. [RESULTS] LDィイD250ィエD2 was 35-40% COィイD22ィエD2 in 21% oxygen, 25% COィイD22ィエD2 in 15% OィイD22ィエD2, 20-25% COィイD22ィエD2 in 10% OィイD22ィエD2, 5-10% COィイD22ィエD2 in 8% OィイD22ィエD2. (2) The activity of mouse [METHODS] We determined activity for 10 min using AUTOMEX II. [RESULTS] (1) The activity compared with in air were decreased 45±11% in 5%COィイD22ィエD2 and 21%OィイD22ィエD2. They were deceased 25±11% in 10%COィイD22ィエD2, 23±11% in 15%COィイD22ィエD2, 7±6% in 20%COィイD22ィエD2, respectively. In 15%OィイD22ィエD2, they were deceased 62±16% in 5%COィイD22ィエD2, 32±14% in 10%COィイD22ィエD2, 15±7% in 15%COィイD22ィエD2, 6±5% in 20%COィイD22ィエD2, respectively. (2) We observed convulsion of mice over 35%COィイD22ィエD2 in 21%OィイD22ィエD2, over 20%COィイD22ィエD2 in 10-15%OィイD22ィエD2, over 5%COィイD22ィエD2 in 8%OィイD22ィエD2, respectively. (3) The changes of respiration in rats [METHODS] We measured the changes of respiratory rates at each COィイD22ィエD2 concentration under 21%OィイD22ィエD2. [RESULTS] The changes were 98±26% after 4 min (4 min), 114±37% (7 min), 85±21% (10 min) in 5% COィイD22ィエD2. They were 74±26% (4 min), 56±17% (7 min) 52±26% (10 min) in 10%COィイD22ィエD2. They were 96±17% (4 min), 101±30% (7 min), 112±39% (10 min) in 20%COィイD22ィエD2. They were 90±16% (4 min), 105±39% (7 min), 99±34% (10 min) 30%COィイD22ィエD2. They were 63±6% (4 min), 62±32% (7 min), 52±35% (10 min) in 40%COィイD22ィエD2. We are planing to study the clearly of the work of respiratory center in COィイD22ィエD2 toxicity.
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