Stem cells have self-renewal and differentiation potential.Cyclin-dependent kinase (CDK) plays an important role in promoting pluripotency and self-renewal.The crucial activity of S-phase,DNA replication,presents a unique opportunity during the cell cycle for the genetic and epigenetic regulation that may be involved in stabilizing the pluripotent state.It is also clear that Myc acts to coordinate both the cell cycle and the pluripotency transcription network in stem cells.Here we review the regulating mechanisms of stem cell cycles and pluripotency by CDK and Myc to help researchers obtain a better understanding of mutual regulation of the cell cycle and the pluripotent state by CDK and Myc which may be exploited in regenerative medicine.

It is important that the oral hospital establish a guarantee system of medical graduation clinical practice quality. Having experienced clinical education for many years,the hospital has formed a system in order to achieve objective management and process management organic unification,which can gradually promote the clinical practice quality.

Objective To explore the immunosuppression effects,outcomes and clinical significance of mesenchymal stem cells (MSCs) transplantation in burn treatment by comparing the levels of WBC,C-reaction protein (CRP),interferon-γ(IFN-γ),interferon-o (TNF-α),interleukin-6 (IL-6),interleukin-10 (IL-10) between control burn models and models conducting MSCs transplantation.Methods After stripping Wharton's Jelly from the neonatal umbilical cord,MSCs was cultured and expanded.Burn models were constructed in male SD rats weighted at (200± 5) g,and randomly grouped for control and MSCs transplantation.The rats in transplantation group were injected subcutaneously with hUCMSCs (1.5× 106) at 24 h after burning.The content of WBC,CRP,IFN-γ,TNF-α,IL-6,IL-10 in blood samples at 0,1,2,3,5 and 7 d after burning were detected by enzyme-linked immunosorbent assay (ELISA).The ELISA results,the wound healing rate at 7,14,21 and 28 d,as well as wound healing time were compared and analyzed statistically by ANOVA between the two groups.Results WBC in control group increased significantly at 1 and 2 d,and CRP in control group increased substantially at 2 and 3 d.IFN-% IL-6 and IL-10 levels in serum showed increase on 5 d,and TNF-α arrived at its peak value at 7 d.By contrast,WBC,CRP,TNF-α,IL-6 and IL-10 of the MSCs transplantation group showed slightly increase after burning and the differences were convinced by statistical analysis,while IFN-γ showed little difference among the two groups.The MSCs transplantation group also showed significantly higher wound healing rate at 14,21,28 d and shorter wound healing time than that of the control.Conclusions MSCs transplantation can suppress the over-inflammatory response by significantly mediating the inflammatory cytokines as WBC,CRP,TNF-α,IL-6,IL-10 in burn.IFN-γseems not affected by MSCs transplantation.MSCs would be suitable to promote wound healing and repair in burn,which is achieved not only by differentiation and paracrine,but also by subtle immunoregulation.

Objective To detect the immune effect of FbaAmAb2 against the surface protein of group A Straptococcus (GAS),and explore the pathogenesis and therapy of GAS infections.Methods By subclonal and bacterial ELISA,the positive hybridoma cells were screened that can produce better titers of FbaAmAb2 against GAS-surface FbaA protein,and were injected into the peritoneal cavities of BALB/c mice to produce ascites.The collected ascites were performed to dilute,as follows,original ascite,1:2,1:4,1:8,and 1:16 to test tube agglutination.Based on the results,we selected appropriate dilution to passively immunize mice,and then challenged the mice with GAS,evaluating FbaAmAb2 neutralizing ability with GAS in mice by the survival rate of the immunized mice.Whether FbaAmAb2 could inhibit the binding of factor H to GAS was confirmed by the invasive inhibition assay.Results The IgG titer of bacteria solution ELISA is 1:160 and the titer of tube agglutination is 1∶8.The protect rates of FbaAmAb2 on preventing mice with GAS infections are as follows:66.67％ in original ascite and 1:2 diluted groups,and 50％ in 1:4 diluted group.Mice in each experimental group were evoked significantly protective immune responses compared with the PBS control by SPSS analysis.FbaAmAb2 can competitively inhibit factor H binding to the surface proteins FbaA of GAS,which decreased the entry of GAS into the cytoplasm of human epithelial cells through the binding of factor H.Conclusion FbaAmAb2 is promising to be used in emergent prevention or the clinical therapy for GAS infection and it is promising starting points for pharmacologic targeting and further development of new therapeutic agents for GAS.

Objective:To explore the early coagulation function changes of penetrating intestinal firearm injury of pig in high-altitude environments.Methods:Twenty healthy long white piglets were selected and divided into the plain group and the high-altitude group using the random number table method, with 10 pigs in each group. Pigs in the plain group were placed in a plain environment at an altitude of 800 meters, while pigs in the high-altitude group were placed in an experimental chamber simulating an altitude of 6 000 meters for 48 hours. Both groups received pistol gunshot to have firearm penetrating wounds to the abdominal intestinal tract and then returned to the plain observation room. At 0, 2, 4, 8, 12 and 24 hours after injury, coagulation in the peripheral blood and fibrinolytic indexes [prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (Fbg), D-dimer (D-D), and fibrinogen degradation product (FDP)], thromboelastogram (TEG) [reaction time (R), clotting time (K), clot formation rate (α), maximum amplitude (MA) and coagulation composite index (CI) ], platelet parameters [platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW), and platelet-large cell ratio (P-LCR)] in the two groups were detected separately.Results:The PT values at 0 and 2 hours after injury in the high-altitude group were significantly lower than those in the plain group, while they were significantly higher at 8, 12 and 24 hours than those in the plain group ( P<0.01); there was no significant difference at 4 hours between the two groups ( P>0.05). The APTT values at 0, 2 and 4 hours after injury in the high-altitude group were significantly lower than those in the plain group, while they were significantly higher at 8, 12 and 24 hours after injury than those in the plain group ( P<0.01). The TT values at 0, 2 and 4 hours after the injury in the high-altitude group were significantly lower than those in the plain group, while they were significantly higher at 12 and 24 hours after injury than those in the plain group ( P<0.01); there was no significant difference at 8 hours after injury between the two groups ( P>0.05). The Fbg, D-D and FDP values at 0, 2, 4, 8, 12 and 24 hours after injury were higher in the high-altitude group than those in the plain group ( P<0.01). The R values at 0, 2 and 4 hours after injury in the high-altitude group were significantly lower than those in the plain group, while they were significantly higher at 8, 12 and 24 hours after injury than those in the plain group ( P<0.01). The K values at 0, 2, 4 and 8 hours after injury in the high-altitude group were significantly lower than those in the plain group, while they were significantly higher at 12 and 24 hours after injury than those in the plain group ( P<0.05 or 0.01). The α angles at 0, 2 and 4 hours after injury in the high-altitude group were significantly higher than those in the plain group, while they were significantly lower at 8, 12 and 24 hours after injury than those in the plain group ( P<0.01). The MA values at 0, 2 and 4 hours after the injury in the high-altitude group were significantly higher than those in the plain group, while they were significantly lower at 8, 12 and 24 hours after injury than those in the plain group ( P<0.01). The CI values at 0, 2 and 4 hours after injury in the high-altitude group were significantly higher than those in the plain group, while they were significantly lower at 8, 12 and 24 hours after injury than those in the plain group ( P<0.01). The PLT values at 0, 2, 4 and 8 hours after injury in the high-altitude group were significantly higher than those in the plain group, while they were significantly lower at 12 and 24 hours after injury than those in the plain group ( P<0.05 or 0.01). The MPV values at 0, 2, 4, 8, 12 and 24 hours after injury in the high-altitude group were significantly higher than those in the plain group ( P<0.01). The PDW values at 2, 4, 8, 12 and 24 hours after injury in the high-altitude group were significantly higher than those in the plain group ( P<0.05 or 0.01), while there was no significant difference in PDW at 0 hour after injury between the two groups ( P>0.05). The P-LCR values at 0, 2, 4, 8, 12 and 24 hours after injury in the high-altitude group were all significantly higher than those in the plain group ( P<0.01). Conclusion:Compared with the plain environments, pig intestinal firearm penetrating injury in the high-altitude environments is more prone to early hypercoagulable state accompanied by mild hyperfibrinolysis, and faster to reach a hypocoagulable state accompanied by obvious hyperfibrinolysis.

【Objective】 To explore the safety of RhD-positive red blood cells (RBCs) immunization schedules in RhD-negative volunteers, so as to facilitate the development of domestic anti-D immunoglobulin. 【Methods】 From January 2018 to April 2020, 23 RhD negative volunteers with informed consent were enrolled and divided into initial immunization group and booster immunization group. The initial immunization included first immunization, second immunization and third immunization. Four groups, i. e. 3 cases of 20 mL, 8 of 30 mL, 6 of 40 mL, and 6 of 50 mL, were involved in initial immunization. After the initial immunization response, booster immunizations were performed every 3 months. According to the anti-D titer before each immunization, the booster immunization doses were set to 0.5, 1 and 2 mL. Whole blood samples of 5mL/ person (time) were collected 24 h and 1 week after each infusion, and the blood routine, liver, kidney and blood coagulation function and anti-D titer were detected. The differences of detection (index) values at 24 h and 1 week after the first immunization and booster immunization in each (dose) group were compared. 【Results】 No statistically significant differences were observed in hemolysis index values (all within the range of medical reference values) 24 h or 1 week after initial immunization among RhD positive RBCs of 20, 30, 40 and 50mL(P>0.05). The differences between the hemolysis index values and the basic values before the immune response (all within the range of medical reference values) after 0.5 or 1 mL booster immunizations were also not statistically different (P>0.05). However, the differences (μmol/L)between total bilirubin levels and the basic values before the immune response (1.55±1.87, 6.29±2.66) were significantly different after 2 mL booster immunization (P<0.05). 【Conclusion】 No risks affecting the safety of RhD negative volunteers was found in the immunization schedule proposed in this study.