• Tuberculosis and Respiratory Diseases
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• v.41 no.3
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• pp.222-230
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• 1994

Background: Paraquat, a widely used herbicide, is extremely toxic, causing multiple organ failure in humans. Paraquat especially leads to irreversible progressive pulmonary fibrosis, which is related to oxygen free radicals. However, its biochemical mechanism is not clear. Natural mechanisms that prevent damage from oxygen free radicals include changes in glutathione level, G6PDH, superoxide dismutase(SOD), catalase, and glutathione peroxidase. The authors think catalase is closely related to paraquat toxicity in the lungs Method: The effects of 3-amino-1,2,4-triazole(aminotriazole), a catalase inhibitor, on mice administered with paraquat were investigated. We studied the effects of aminotriazole on the survival of mice administered with paraquat, by comparing life spans between the group to which paraquat had been administered and the group to which a combination of paraquat and aminotriazole had been administered. We measured glutathion level, glucose 6-phosphate dehydrogenase(G6PDH), superoxide dismutase(SOD), catalase, and glutathione peroxidase(GPx) in the lung tissue of 4 groups of mice: the control group, group A(aminotriazole injected), group B(paraquat administered), group C(paraquat and aminotriazole administered). Results: The mortality of mice administered with paraquat which were treated with aminotriazole was significantly increased compared with those of mice not treated with aminotriazole. Glutathione level in group B was decreased by 20%, a significant decrease compared with the control group. However, this level was not changed by the administration of aminotriazole(group C). The activity of G6PDH in all groups was not significantly changed compared with the control group. The activities of SOD, catalase, and glutathione peroxidase(GPx) in the lung tissue were significantly decreased by paraquat administration(group B); catalase showed the largest decrease. Catalase and GPX were significantly decreased by aminotriazole treatment in mice administered with paraquat but change in SOD activity was not significant(group C). Conclusion: Decrease in catalase activity by paraquat suggests that paraquat toxicity in the lungs is closely related to catalase activity. Paraquat toxicity in mice is enhanced by aminotriazole administration, and its result is related to the decrease of catalase activity rather than glutathione level in the lungs. Production of hydroxyl radicals, the most reactive oxygen metabolite, is accelerated due to increased hydrogen peroxide by catalase inhibition and the lung damage probably results from nonspecific tissue injury of hydroxyl radicals.

• Journal of Korean Philosophical Society
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• v.131
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• pp.77-103
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• 2014

It is well known that Nietzsche insists on the affirmation of life, and the subject of 'affirmation of life' is a familiar one in Nietzsche literature. We want to throw an unfamiliar light on this familiar subject, connecting the theme of affirmation with that of redemption, and insisting on the centrality of the theme of redemption in Zarathustra's teaching of ${\ddot{U}}bermensch$. For Nietzsche, the redemption of human life means that its life is endowed with some meaning and its existence is positively justified. With this redemption, an active affirmation of life is possible, which means that we not only endure this life once but also request it for indefinite times. According to Nietzsche, for this kind of redemption and active affirmation we need an ultimate ground of meaning and only the excellence of life, that is, of 'will to power' can serve as this ultimate ground. Accepting the Greek way of identifying virtue with excellence, Nietzsche thought that life can justify itself at the ultimate form of life in ${\ddot{U}}bermensch$. Then, through ${\ddot{U}}bermensch$ the way is opened for man to endow meanings on and justify its life. That is, ${\ddot{U}}bermensch$ is not only the one who affirms its life, but also the very condition in which humanity can justify its life in general. With the goal and ideal of ${\ddot{U}}bermensch$ accepted, the affirmation and redemption of an individual life depends on how it manages to create its own life in relation to this goal and ideal. According to Nietzsche, though we cannot go back to the past, we still can recreate it and change its meanings through working on the future. Only those who try to create a meaningful future and thus recreate the past could redeem and affirm their own lives. That is, for Nietzsche, to affirm and redeem one's life means not just to change one's attitude to life but to create and recreate it with the eye for ${\ddot{U}}bermensch$.