Objective To research the effect of melatonin against glutamate excitotoxicity. Methods The model of glutamate-induced excitotoxic damage was built up in rat cerebral cortical cell culture. The effect of mela- tonin against excitotoxic injury was observed by determining the leakage rate of lactate dehydrogenase(LDH) from neurons. ResultsThe leakage rate of LDH wasn＇t decreased markedly when cultures were exposed to melatonin be- fore, during or 6 h after glutamate treatment. The leakage rate of LDH was decreased significantly when melatonin was administered 0 h, 2 h or 4 h after the cultures were exposed to glutamate. The inhibitory function of melatonin on LDH leakage was most effective at 2 h and 4 h. Conclusion Melatonin has protective effects on neurons damaged by glutamate in a certain time limit.

According to the constructivism approach, instructors have to adapt to the role of fa-cilitators but not teachers. Whereas a teacher gives a didactic lecture that covers the subject matter , a fa-cilitator helps the learner to get to his or her own understanding of the content. In the former scenario the learner plays a passive role and in the latter scenario the learner plays an active role in the learning pro-cess. Under the guidance of this theory, a multi-dimension teaching model based on classroom teaching, network platform and innovate experiments has been established in the course of basis of clinical labora-tory. It has been found that this model is conducive to raising students' interests in learning and to culti-vating student's comprehensive quality.

Objective To evaluate whether immunization with △A146 Ply could confer protections against pneumococcal infections in murine models and to reveal the possible role of △A146 Ply-specific IgG in the protection elicited.MethodsBALB/c mice were immunized intraperitoneally with △A146 Ply or PBS plus alum.Fourteen days after the third immunization,mice were intranasally challenged with serotype 14 and 19F Streptococcus pneumoniae.Three days after inoculation,lungs were removed from mice and homogenized in PBS,followed by plated on red cell plates.Viable bacteria were counted after overnight incubation.As to the sepsis models,vaccinated mice were challenged intraperitoneally with different dosage bacteria of D39 and serotype 3 strain.The numbers of CFU log10 were compared by Mann Whitney U test and survival rates were analyzed using log-rank test.Passive protection was used to evaluate the role of △A146 Ply-specific IgG in the protection against otherwise lethal infection resulted from D39.Results ELISA analysis demonstrated higher titer specific antibody responses to △A146 Ply was produced after 3 times immunization.Mice boosted twice with △A146 Ply survived significantly longer than that for mice boosted once with △A146 Ply in Alum adjuvant,which were significantly longer than that of control group.Immunization with △A146 Ply was effective in reducing the numbers of pneumococcal strain 31614(serotype 14) and 31693(serotype 19F),which resulted in 50-and 20-fold decreases in bacterial load in the lungs respectively when compared to control protein-immunized mice.60% of vaccinated mice survived the infection with pneumococcal D39 of 1200 CFU.60% protection was achieved when mice intraperitoneally infected with D39 and received △A146 Ply-specific IgG,whereas no mice survived the infection when they were passively administered with △A146 Ply-specific IgG depleted antisera.Conclusion Immunization with △A146 Ply could confer protection against pneumococcal infections,and protection elicited was mediated by △A146 Ply-specific IgG.