Objective: Morphine concentration measured in postmortem tissues may or may not reflect antemortem concentration. We measured levels of morphine in autopsied tissues to determine whether morphine distribution in morph...Objective: Morphine concentration measured in postmortem tissues may or may not reflect antemortem concentration. We measured levels of morphine in autopsied tissues to determine whether morphine distribution in morphine-dependent rats is altered after death. Methods: Solid-phase extraction was used to extract morphine from the samples, and morphine levels were measured at 0-96 h postmortem using gas chromatography. Results: The study of the morphine dependent rats showed a significant (P<0.05) increase of morphine concentration in postmortem cardiac blood, liver tissues and kidneys tissues. A significant increase was also observed at 72 h and 96 h postmortem in the brain, while morphine levels in cardiac tissues only increased at 24 h and 96 h postmortem. These changes were associated with an observed pH rapid decrease: pH of cardiac blood dropped from 7.36±0.15 to 6.86±0.09 (P<0.01), pH of liver tissues from 6.98±0.04 to 6.34±0.03 (P<0.05). Conclusion: The postmortem regional distribution of morphine occurs in dependent rats, but different from the change that occurs in acute poisoning rats. The morphine concentration in cardiac blood and tissues tends to increase during the period of 0-96 h postmortem in dependent rats. Morphine concentration increases with pH rapid decrease. The antemortem internal amount of morphine affects its postmortem regional distribution. It appears that several mechanisms are accountable for postmortem morphine distribution. The understanding of the mechanisms and patterns may eventually lead to better choices of samples which may better represent antemortem drug levels.展开更多
The emergence of media convergence have so huge impact on paper-based media that paper-based media no longer has a monopoly. Some people assert that paper-based media will come to an end. However, the author believes ...The emergence of media convergence have so huge impact on paper-based media that paper-based media no longer has a monopoly. Some people assert that paper-based media will come to an end. However, the author believes that the paper media will not come to an end under the media convergence trend. It will develop parallel with media integration. The reason why the author has this view is that, on one hand, paper-based media has its unique physical characteristics. In the real world, paper media brought us the aesthetic experience by ＂five senses＂ . It cannot be replaced by the media convergence. The paper media will also make survival steering dimension; on the other hand, cultural heritage of the paper media make itself a unique appreciation of the value and not transcendent. Therefore, the paper media in the media convergence trend will continue to exist and turned to be ＂concept book＂ that admiring is the main part and reading supplemented.展开更多
文摘Objective: Morphine concentration measured in postmortem tissues may or may not reflect antemortem concentration. We measured levels of morphine in autopsied tissues to determine whether morphine distribution in morphine-dependent rats is altered after death. Methods: Solid-phase extraction was used to extract morphine from the samples, and morphine levels were measured at 0-96 h postmortem using gas chromatography. Results: The study of the morphine dependent rats showed a significant (P<0.05) increase of morphine concentration in postmortem cardiac blood, liver tissues and kidneys tissues. A significant increase was also observed at 72 h and 96 h postmortem in the brain, while morphine levels in cardiac tissues only increased at 24 h and 96 h postmortem. These changes were associated with an observed pH rapid decrease: pH of cardiac blood dropped from 7.36±0.15 to 6.86±0.09 (P<0.01), pH of liver tissues from 6.98±0.04 to 6.34±0.03 (P<0.05). Conclusion: The postmortem regional distribution of morphine occurs in dependent rats, but different from the change that occurs in acute poisoning rats. The morphine concentration in cardiac blood and tissues tends to increase during the period of 0-96 h postmortem in dependent rats. Morphine concentration increases with pH rapid decrease. The antemortem internal amount of morphine affects its postmortem regional distribution. It appears that several mechanisms are accountable for postmortem morphine distribution. The understanding of the mechanisms and patterns may eventually lead to better choices of samples which may better represent antemortem drug levels.
文摘The emergence of media convergence have so huge impact on paper-based media that paper-based media no longer has a monopoly. Some people assert that paper-based media will come to an end. However, the author believes that the paper media will not come to an end under the media convergence trend. It will develop parallel with media integration. The reason why the author has this view is that, on one hand, paper-based media has its unique physical characteristics. In the real world, paper media brought us the aesthetic experience by ＂five senses＂ . It cannot be replaced by the media convergence. The paper media will also make survival steering dimension; on the other hand, cultural heritage of the paper media make itself a unique appreciation of the value and not transcendent. Therefore, the paper media in the media convergence trend will continue to exist and turned to be ＂concept book＂ that admiring is the main part and reading supplemented.
