Alteration of metabolic characteristics on the masseter muscle fiber of unilateral chewing rats and its adenosine monophosphate activated protein kinase regulatory mechanism / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study aims to determine the influence of unilateral chewing on metabolic characteristics of masseter muscle fibers in rats and the regulatory effect of an adenosine monophosphate activated protein kinase (AMPK) signal pathway on metabolism.</p><p><b>METHODS</b>Rats were submitted to exodontia of all the right maxillary molars and divided into 2, 4, 6, and 8 weeks groups, and corresponding control groups were set as well. Sections were stained by nicotine adenine dinucleotide tetrazolim reductase(NADH-TRase) to demonstrate the types, proportion, and density of masseter muscle fibers. AMPKα1 and p-AMPK(Thr172) levels in bilateral masseter muscles were detected by Western blot.</p><p><b>RESULTS</b>In the 2-week group, the percentage of dark fibers augmented in the ipsilateral side, whereas the percentage of intermediary fibers in the contralateral side was increased accompanied by a decrease of light fibers, compared with the control group (P<0.05). The percentage of dark fibers was increased in the bilateral sides, whereas the percentage of dark fiber in the ipsilateral sides surpassed that of the contralateral sides in the 4, 6, and 8-week groups. The percentage of intermediary fibers was decreased in the bilateral sides in the 6 and 8-week groups (P<0.05). The percentage of light fibers was reduced in the ipsilateral sides in the 8-week group, whereas no alteration was observed in contralateral sides (P>0.05). In the ipsilateral sides, p-AMPK (Thr172)/AMPKα1 levels were increased in the 2 and 4-week groups (P<0.05), whereas no change was observed in the contralateral sides in either group (P>0.05).</p><p><b>CONCLUSIONS</b>Unilateral chewing increases the oxidative metabolic ability in bilateral masseter muscle fibers especially in the non-working side accompanied with change of muscle fiber types. The improvement of aerobic metabolism ability is related to the AMPK signal pathway.
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Thinking through survey of medical ethics practice of medical students / 中华医学教育探索杂志

Objective To investigate meclical ethits level of first-year mecdical stuclents in Guangzhou medical college,which contributes to provide guidance of medical ethics education for interns. Methods To investigate 183 cases of first-year medical students. They were asked to deal with a case of 'a vagrant needed emergency treatment'. The statistics datum were classified according to 'norms of medical ethics and ways of implementation made by the Ministry of Health for medical staff'.Results 99.45% of them thought they should immediately save patients' live;but less than 28.96%thought of using cheap and fine medicines;only 38.80% mentioned the patients' mood. And there was no significant difference between boys and girls(P>0.05). Conclusion Medical students have already established a 'life-saving' awareness when they are freshman, but they also need to learn how to put ethics into practice.