Protective effects of astragalus extract against intermittent hypoxia-induced hippocampal neurons impairment in rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Intermittent hypoxia is the main pathophysiological cause of the obstructive sleep apnea syndrome. Astragalus shows improvement of spatial learning and memory abilities under intermittent hypoxia. Our study aimed to investigate the protective effect of astragalus against intermittent hypoxia induced-hippocampal neurons impairment in rats and lay the theoretical foundation for the sleep apnea improvement in cognitive function by astragalus.</p><p><b>METHODS</b>Male Wistar rats were divided into 4 groups: blank control group, normoxia group, intermittent hypoxia group and astragalus treated intermittent hypoxia group. After 6-week treatment, apoptosis of neurons was evaluated by terminal deoxynucleotidyl-transferase-mediated dUTP nick end-labeling (TUNEL) assay. Furthermore, the expression of HIF-1a was detected by real-time reverse transcription polymerase chain reaction (RT-PCR) at the mRNA level as well as by immunohistochemistry (IHC) and Western blotting at the protein level.</p><p><b>RESULTS</b>HPLC analysis indicated that astragaloside IV, astragaloside II and astragaloside I were the main compounds in astragals extract. Astragalus extract reduced the apoptosis of hippocampal neurons (P < 0.05) and decreased the expression of HIF-1a at both the mRNA and protein levels in hippocampus compared with non-treated groups (P < 0.05).</p><p><b>CONCLUSION</b>Astragalus protects against intermittent hypoxia-induced hippocampal neurons impairment in rats.</p>

A study on detection method of lamivudine related mutations in hepatitis B virus polymerase gene / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To establish a simple and accurate method for rapid detection of lamivudine related mutations in hepatitis B virus (HBV) polymerase gene.</p><p><b>METHODS</b>HBV polymerase gene fragments of covering B and C active region were amplified by nested polymerase chain reaction (nPCR) or nested mismatched PCR. The PCR products were digested with Nde I or Nia III and subjected to electrophoresis on agarose gel, respectively. The patterns of restriction fragment length polymorphism (RFLP) were distinguished. Using this method, thirty patients with chronic hepatitis B and treated with lamivudine for at least one year were analysed for the lamivudine related mutations in polymerase gene. Sixteen cases without lamivudine therapy were used as controls. Some of the patients were also analysed by clone sequencing.</p><p><b>RESULTS</b>The nested mismatched PCR-RFLP method was simple, accurate and rapid. The whole experiments could be finished in eleven hours. The least titers of HBV DNA which could be detected was 10.3 copies/ml. The wild or mutant strains judged by RFLP were identified by clone sequencing. Mutation in the tyrosine methionine aspartic aspartic acid (YMDD) motif of HBV polymerase gene was found in eight patients and mutations of YMDD motif associated with L526M were found in another three patients. However, there were no such mutations in the control cases.</p><p><b>CONCLUSION</b>The nested PCR-RFLP is considered as a simple and accurate method for rapid detection of lamivudine related mutations in HBV polymerase gene. It is suitable for larger number of sample detection.</p>