The effect of cyclic tensile force on the actin cytoskeleton organization and morphology of human periodontal ligament cells.

To explore Girdin/Akt pathway protein expression and morphology change by cyclic tension in the periodontal ligament cells. Human periodontal ligament cells were exposed to cyclic tension force at 4000 µstrain and 0.5 Hz for 6 h though a four-point bending system. Cyclic tension force upregulated F-actin, Girdin and Akt expression in hPDL. In transmission electron microscope assay showed that there are more and bigger mitochondria, more and longer cynapses, more cellular organisms after tension force stimulation than control. The actin filament was changed to be regular lines and pointed to poles of cells. However, we found that the Girdin-depleted cells are small and there are more micro-organisms including more lysosomes and matrix vesicles than control. These finding suggest that the STAT3/Girdin/Akt pathway in PDL to response to mechanical stimulation as well, and Girdin may play a significant role in triggering cell proliferation and migration during orthodontic treatment. It provided an insight into the molecular basis for development of a vitro cell model in studying orthodontic treatment.

Goose parvovirus and the protein NS1 induce apoptosis through the AIF-mitochondrial pathway in goose embryo fibroblasts.

In this study, the effects of Goose parvovirus (GPV) infection as well as the possible role of NS1 protein on apoptosis induction in goose embryo fibroblast (GEF) cells were examined. Flow cytometry analysis and TUNEL assays revealed that GPV infection and NS1 transfection induced significant apoptosis in GEF cells compared to what was observed in mock-infected cells. Interestingly, the increase in the rate of apoptosis detected in GPV-infected GEFs was accompanied by an increased viral load in the cells. In addition, the apoptotic pathway was mediated by apoptosis-inducing factors (AIFs) and internal factors that influence the release of AIFs. The results indicated that the mitochondrial membrane potential was decreased, and AIF expression was increased in the nucleus (P < 0.01). Reactive oxygen species (ROS) increased gradually within 48 h (P < 0.001). Cathepsin D activities were also increased (P < 0.05). The results demonstrated that the AIF-mediated pathway is a new mitochondrial apoptotic pathway and that mitochondrial depolarization, ROS content, and cathepsin D activities are the key factors influencing apoptosis in GEF cells.

Can HB vaccine yield a booster effect on individuals with positive serum anti-HBs and anti-HBc markers?

AIM: To evaluate if HB vaccination can yield a booster effect on the anti-HBs level of those naturally acquired HBV positive markers. METHODS: Sera were collected from 1399 newly enrolled university students aged between 18-20 years at the entrance medical examination in 2001. Forty-four students (28 males and 16 females) with positive serum anti-HBs and anti-HBc markers served as an observation group and another 44 students (24 males and 20 females) without any HBV markers as the control. HB vaccination was given to all the students without positive serum HBsAg according to 0, 1, 6 month regimen and the peripheral venous blood was sampled from those of both observation and control groups for anti-HBs detection one month after the second and third doses. Anti-HBs levels were measured by ELISA. RESULTS: The seroconversion rate of anti-HBs in the control group was 100% after the second dose, but the geometric mean titers (GMTs) were low. The tendency of serum anti-HBs changes after the 3rd dose was completely different between the two groups. Although more than half of those with positive anti-HBs and anti-HBc showed a mild increase of anti-HBs levels after the 2nd boosting dose (mean anti-HBs level was 320:198 mIU), but the increase of serum anti-HBs titer was much smaller than that in the control group. The averages of their initial serum anti-HBs levels and the levels after the 2nd and 3rd doses were 198, 320 and 275 mIU respectively. All the subjects from the control group had an obvious increase in their serum anti-HBs levels which was nearly 4 times the baseline level (302:78 mIU). CONCLUSION: HB vaccination can not enhance anti-HBs levels in those with positive serum anti-HBs and anti-HBc markers.