Objective To study the effect of metformin on the growth of megakaryocytic leukemia cell line Dami and to explore the molecular mechanisms of the inhibitory effect of metformin on the proliferation of Dami. Methods The Dami cells were cultured and divided into control and 1,2,4,8,16 and 32 mmol·L-1 metformin groups.Then MTT test was performed to detect the inhitory rate of proliferation of Dami cells after treated with different concentrations of metformin. Flow cytometry was used to examine the distribution of cell cycle, and Western blotting was carried out to analyze the expressions of Cdc2 and CylinB1 and the phosphorylation of Cdc2. Results The MTT results showed that compared with control group,the inhibitory rates of proliferation of the Dami cells in 32 mmol·L-1 metformin groups at 0,24,48,72 and 96 h (35.1%±2.3%,49.7%±5.1%, 78.85±0.9%,79.1%± 3.0%%,and 85.2%± 3.2%)were significantly increased(P<0.01),Furthermore, after metformin treatment for 72 h,the inhibitory rates of proliferation of the Dami cells in 1,2,4,8,16 and 32 mmol·L-1 metformin groups were (33.8 ± 0.3)%,(51.9 ± 0.2)%,(59.4 ± 1.6)%,(65.5 ± 2.0)%, (75.5±0.9)%,and (79.1±3.0)%,respectively. Metformin inhibited the growth of Dami cells in a time-and dose-dependent manner. The flow cytometry results results revealed that compared with control group, the percentages of Dami cells in G2/M phase in 1,2 and 4 mmol·L-1 metformin groups were increased from (26.0± 0.5)% to (38.5 ± 1.5 )%, (48.4 ± 1.1 )%, and (58.2 ± 2.7 )%;there was significant difference in the percentages of Dami cells in G2/M phase between control group and 4 mmol·L-1 metformin group (P<0.01). Western blotting analysis showed that compared with control group, the expressions of Cdc2 and CyclinB were evidently reduced, the phosophorylation of Cdc2 at Tyr1 5 was up-regulated, and the phosphorylation at Thr1 6 1 was down-regulated.Conclusion Metformin can inhibit the growth of Dami cells and induce G2/M arrest,and its mechanism may be related to inhibiting the activation of Cdc2/CyclinB1 complex.

Objective To investigate if down regulation of MTDH could inhibit proliferation and induce apoptosis in breast cancer SK-BR-3 cells.Methods RNA interference was employed to reduce MTDH expression in human breast cancer SK-BR-3 cells.Western blot assay was applied to measure the down regulation of MTDH.MTT assay was performed to assess the proliferation of SK-BR-3 cell.Flow cytometry was employed to detect cell cycle and apoptosis.Western blot assay was applied to detect the molecular alterations that was associated with cell proliferation,cell cycle and apoptosis.Results MTDH down regulation significantly inhibited cell proliferation.48 hours and 72 hours after trasnfection,the absorbance value(A value)in blank control,negative control and treatment group was (2.0 ± 0.1) vs (1.9 ± 0.3) vs (0.9 ± 0.1) (P =0.02) and (2.7 ± 0.2) vs (2.5 ± 0.4) vs (1.3 ± 0.2) (P =0.008).MTDH down regulation resulted in accumulation of the G0/G1 phase cells and reduction of S and G2/M phase cells.Moreover,MTDH down regulation significantly induced cell apoptosis.The cell apoptosis rate in blank control,negative control and trial group was (1.3 ± 0.2) ％,(1.4 ± 0.3) ％ and (19.6 ± 2.7) ％ (P =0.012).MTDH down regulation resulted in a decreased expression of cyclinD1 and Bcl-2,an increased expression of P21 and the activation of caspase-3.Conclusions Reduced MTDH expression in SKBR-3 cells can inhibit proliferation and induce apoptosis,which may be associated with decreased expression of cyclinD1 and Bcl-2,an increased expression of P21 and the activation of caspase-3.

Marinesco-Sj?gren syndrome (MSS), also known as hereditary ataxia-dwarf-mental retardation syndrome, is a rare autosomal recessive ataxia syndrome. This article reviews the recent advance in clinic characteristics, pathogenic gene mutation sites, pathogenesis and clinic diagnosis and treatment of MSS, in order to improve clinicians' understanding of the disease and diagnosis and treatment level, and reduce the missed diagnosis and misdiagnosis of the disease.

Objective To evaluate the effect of left atrial enlargement on atrial myocardial fibrosis degree and levels of the angiotensinⅡ (AngⅡ)/Rac GTPase activating protein 1 (Rac1)/signal transducersand activators of transcription 3 (STAT3) signaling pathways expressing in patients with persistent atrial fibrillation and rheumatic heart disease (RHD). Methods From March to December 2011, 30 patients with RHD who underwent prosthetic valve replacement in our hospital were enrolled, including 16 males and 14 females, aged 42-70 (56.9±6.8) years. Twenty RHD patients with persistent atrial fibrillation as a research group and ten RHD patients with sinus rhythm as a control group (group A) underwent transthoracic echocardiography and right atrial appendage (RAA) tissue samples were obtained from these patients during mitral/aortic valve replacement operation. The research group according to left atrial diameter (LAD) was divided into two groups, ten patients in each group: a group B with LAD of 50–65 mm and a group C with LAD of LAD>65 mm. For each sample, histological examination was performed by hematoxylin-eosin and Masson’s trichrome staining. Light-microscopic pictures of atrial tissues samples were stained and tissue fibrosis degree in each group was analyzed. AngⅡ concentration was measured by enzyme linked immunosorbent assay. Rac1 and STAT3 were measured by western blotting. Results LAD was significantly greater in AF patients with RHD than in the control group. Hematoxylin-eosin staining demonstrated highly organized arrangement of atrial muscles in the control group and significant derangement in both group B and group C with reduced cell density and increased cell size. Moreover, Masson’s trichrome staining showed that atrial myocytes were surrounded by large trunks of collagen fibers in both group B and group C, but not in the group A. There was a positive correlation between atrial tissue fibrosis and LAD. AngⅡ content was positively correlated with LAD. Similarly, Rac1 and STAT3 protein levels were found considerably higher in the group C and group B than in the group A with excellent correlation to LAD. Conclusion In patients with RHD complicated with persistent atrial fibrillation, the degree of atrial fibrosis and the expression level of AngⅡ/Rac1/STAT3 signaling pathways significantly increase with the left atrialenlargement.