Objective: To investigate the antitumor effect of lactobacillus peptidoglycan (PG) and explore its possible mechanisms. Methods: The inhibition for colon tumor growth, and the influence on the activities of CTL, NK, PM?, IL-1, IL-2, TNF-?, IFN-?and nitric oxide secretion were investigated in mice by cell culture, DNA agrose gel electrophoresis, respectively. Results: Growth in vivo of CT26 colon tumor was significantly inhibited by ip injection of PG. PG also induced significantly the activities of IL-1, TNF-?, IFN-?, CTL, NK, PM?and the production of nitric oxide, but had no effect on the activity of IL-2. Conclusion: The peptidoglycan derived from lactobacillus inhibited the colon tumor growth through activation of murine immunity. The antitumor effect of PG maybe partly if not all, induced, by the enhanced production of IFN-?, TNF-?and NO, through activation of NK cell and PM?. Key word: peptidoglycan; antitumor; immunity; cell activity; cytokine

Objective:To investigate the attentional bias for negative emotional facial expressions in major depressive disorder(MDD).Methods:Twenty MDD participants were selected from a larger pool of patients (n=35),diagnosed as depression with the Chinese Classification and Diagnostic Criteria of Mental Disorders Version 3 (CCMD-3),according to the Hamilton Depression Scale (HAMD) and Beck Depression Inventory (BDI).And 20 non-depression control participants(NC)matched with MDD group on age,gender and education level.All participants completed an exogenous cueing task which consisted of two kinds of cue types(valid and invalid trial)and two kinds of face types(neutral faces and negative faces).Results:Patients with MDD showed more larger cue validity effect for negative faces compared with neutral faces(21.73 ms vs.3.91 ms,P<0.01).They showed a stronger attentional engagement for negative faces in comparison with non-depressed participants(17.25 ms vs.1.64 ms,P<0.001).The NC group directed attention away from negative faces,more rapidly disengaging their attention compared with MDD,but the differences showed no significant(-1.50 ms vs.0.57 ms,P>0.05).Conclusion:These results support the assumption that MDD is associated with attentional bias for negative information,and deficits protective bias for it.