BACKGROUND: Changes in extracellular of chondrocyte can reflect influence of external force on temporomandibular joint and adaptability of body to external force. OBJECTIVE: To study the effect of cyclic tensile stress on main extracellular matrix of condylar chondrocyte.METHODS: The cyclic tensile stress was exposed to the third passage condylar chondrocyte for 0, 1, 6, 12 and 24 hours, respectively, using a Flexcell Strain Unit-5000T system (10% surface elongation, 6 cycles/min). After mechanical loading, total RNA was extracted from the cells harvested from Six-well BioFlex flexible cell Petri Dish, reverse transcribed, and reverse trabscription-PCR was performed to quantify mRNA levels for type Ⅱ collagen and aggrecan.RESULTS AND CONCLUSION: Compared with the control group (0 hour group), both type Ⅱ collagen and aggrecan mRNA expression was significantly increased after loading for 6 hours (P < 0.05), but began to decrease since 12 hours, and significantly decreased at 24 hours (P < 0.05). Results showed that cyclical tensile stress stimuli can affect the synthesis of main extracellular matrix of condylar cartilage, i.e. the synthesis was gradually enhanced with prolonged stimulation duration, but significantly inhibited in response to further stress stimuli.

Objective To prepare recombinant plasminogen activator(Pla) protein in E.coli BL21 cells that can be used in studying interactions between Yersinia pestis proteins and immunologic diagnosis of plague.Methods The pla gene was amplified by PCR and cloned into the pET28a expression vector.E.coli BL21 competent cells were transformed with the recombinant vectors, and isopropyl-β-D-thiogalactopyranoside ( IPTG) was added to induce expression of Pla protein. The expressed protein was detected by SDS-PAGE electrophoresis.The inclusion bodies of Pla protein were denatured in 8 mol/L urea, and then refolded using gradient urea solutions.The purified protein was identified by SDS-PAGE electrophoresis and Western blot.Results and Conclusion The constructed expression vector was demonstrated to be correct through agarose gel electrophoresis and sequencing.The recombinant Pla protein was accumulated as an inclusion body in E.coli, and the overexpression product was mainly a target protein, the yield of which was very high.SDS-PAGE purity of the bioactive Pla protein was obtained by denaturing and refolding the inclusion bodies.This study provides a simple and quick method for highly efficient preparation of biologically active Pla protein.

BACKGROUND: Because of complicated physiological environment and difficulty to control experimental conditions, it is difficult to get satisfactory results from in vivo studies of cell mechanics.OBJECTIVE: To study the action and mechanism of p38MAPK signaling pathways on myoblast apoptosis based on successful construction of in vitro mechanical stimulation models.METHODS: The C2C12 cells cultured in vitro were divided into control group and SB203580 treatment group. Cyclic tensile stress was applied on the C2C12 myoblast cells for 0, 6, 12 and 24 hours in each group. The Flexcell Strain Unit-5000T was used to expose C2C12 myoblast cell to an equiaxial cyclic of 15% magnitude and a frequency of 10 cycles/min, each cycle including the 3 s stretch and 3 s relaxation. Hoechst 33258 fluorescent staining and optical microscope were used to detect cell apoptosis. RT-PCR, flow cytometric analysis were used to observe the apoptosis of C2C12 myoblast cells and Western blotting were used to detect the activity of p38MAPK and p-p38MAPK. RESULTS AND CONCLUSION: The optical microscope tested the change in the morphology. Hoechst 33258 staining showed that after treatment with cyclic stress, the cell took the typical appearance of apoptosis with chromatin condensation and apoptotic bodies. RT-PCR and flow cytometry showed that with the extension of time the rate of the apoptosis of C2C12 myoblast cell increased. And cells imposed SB203580 before imposing cyclical tensile stress, the results showed that the apoptosis was markedly affected, and the p-p38MAPK expression declined apparently. These findings demonstrate that p38MAPK signaling pathways in stress mediated into C2C12 myoblast cell apoptosis plays an important role.

Objective To establish a simple and quick loop-mediated isothermal amplification (LAMP)method for detection of Yersinia pestis.Methods LAMP Primers were designed based on the specific sequence 3a in Y.pestis chromosome.LAMP reaction results were detected using turbidity meter or visual method.The specificity of the constructed method was evaluated by detecting Y.pestis and its closely-related bacteria.The different dilution DNA template was detected with LAMP and PCR to evaluate the sensitivity of the method.Results Thirty strains of bacteria closely related to Y.pestis were detected by the constructed LAMP,and all the results were negative,indicating that the method had a very high specificity.The detection sensitivity of this LAMP assay was 20 pg of DNA per reaction,which was ten-fold that of the regular PCR.The detection reaction was completed in 25 min.Conclusion This LAMP method is quick,sensitive, specific and simple,which is expecked to become an effective method for rapid detection of Y.pestis on the scene.

Objective: To investigate the clinical manifestations and pathological changes of benign lymphoadenosis of oral mucosa. Methods: The clinical data of 98 cases of benign lymphoadenosis of oral mucosa were analyzed. Results: The clinical manifestations of benign lymphoadenosis of oral mucosa included erosive ulcer (64%) and nodule (9%) and the rate of misdiagnosis was 98%. Neutrophil infiltration occurred in the epithelium of 51% cases and the lymphocyte was diffusely infiltrated in lamina propria of 83% cases. Conclusions When the mucous membrane of the lamina propria is characterized by complex cell components, diffuse infiltrating lymphocytes and infiltration of neutrophils in mucosal epithelium without erosion and ulceration, it is necessary to highly suspect benign lymphoadenosis of oral mucosa. Finding the focal aggregation of lymphoid follicles or lymphocytes is helpful for the correct diagnosis.

OBJECTIVES: This study aims to investigate the effects of tumor-stromal fibroblasts (TSFs) on the proliferation, invasion, and migration of salivary gland pleomorphic adenoma (SPA) cells in vitro. METHODS: Salivary gland pleomorphic adenoma cells (SPACs), TSFs, and peri-tumorous normal fibroblasts (NFs) were obtained by tissue primary culture and identified by immunocytochemical staining. The conditioned medium was obtained from TSF and NF in logarithmic phase. SPACs were cultured by conditioned medium and treated by TSF (group TSF-SPAC) and NF (group NF-SPAC). SPACs were used as the control group. The proliferation, invasion, and migration of the three groups of cells were detected by MTT, transwell, and scratch assays, respectively. The expression of vascular endothelial growth factor (VEGF) in the three groups was tested by enzyme linked immunosorbent assay (ELISA). RESULTS: Immunocytochemical staining showed positive vimentin expression in NF and TSF. Results also indicated the weak positive expression of α-smooth muscle actin (SMA) and fibroblast activation protein (FAP) in TSFs and the negative expression of α-SMA and FAP in NFs. MTT assay showed that cell proliferation in the TSF-SPAC group was significantly different from that in the NF-SPAC and SPAC groups (P<0.05). Cell proliferation was not different between the NF-SPAC and SPAC groups (P>0.05). Transwell and scratch assays showed no difference in cell invasion and migration among the groups (P>0.05). ELISA showed that no significant difference in VEGF expression among the three groups (P>0.05). CONCLUSIONS TSFs may be involved in SPA biological behavior by promoting the proliferation of SPACs but has no effect on the invasion and migration of SPACs in vitro. Hence, TSF may be a new therapeutic target in SPA treatment.
Humans ; Adenoma, Pleomorphic/metabolism* ; Vascular Endothelial Growth Factor A ; Culture Media, Conditioned/metabolism* ; Fibroblasts/metabolism* ; Salivary Glands/metabolism*