[Objective] To investigate into the cellular mechanism of growth promotion due to shear stress by studying G1-phase events responsible for the suppression of cell transition from the G1 to S phase of the cell cycle,and to establish the most suitable physiological stress to stimulate bone formation.[Methods]The osteoblasts derived from Kunming murine's calvaria were exposed to Fliud shear stress(FSS:12 dyn/cm2)for 0,0.25,0.5,1,2,4 h,respectively.In the flow chamber,its impact on cell proliferation,differentiation and the effection of cell cycle's G1/S checkpoint were recorded.The cell proliferation was studied by MTT assay.The cell differentiation was assessed through alkaline phosphatase(ALP)activity assay.Flow-cytometry,immunofluorescence and RT-PCR techniques were used to evaluate the proportion of S phase in cell cycle,the activity of CDK2,CDK4 and the expression of E2F-1,p27mRNA,which demonstrate how FSS underlying multiple mechanisms to enhance the cell cycle progression from G1 to S phase.[Results]FSS increased proliferation and advanced the time in cell growth curve,but after 1,2,4 h,the proliferation was inhibited.The FSS also increased the ALP activity,which were significantly stimulated at 0.25 and 0.5 h after shear stress(128% and 158 % of control);but the FSS decreased ALP activity at 1,2,and 4 hs.The proportion of S phase in cell cycle raised within the early period.The S phase rate significantly increased at 0.5 h(P

Objective To investigate the effect of atorvastatin on cardiac fibrosis and on the expression of NF-?B and TNF-? in a rat model of type 2 diabetes mellitus.Methods Sixty SD rats were randomly divided into 3 groups.In control group(n=20) the rats were fed with normal food and gavaged with normal saline.In diabetes group(n=20) the rats with type 2 diabetes was induced by intraperitoneal injection of low doses of streptozotocin(STZ),and the rats were fed with high fat diet.In atorvastatin group(n=20) diabetes was reproduced in rats and atorvastatin 20mg/(kg?d) was gavaged for 12 weeks.The pathological changes in myocardial cells were observed under light microscope.Collagen content was observed by Masson staining.The contents of TNF? were determined in plasma and cardiac tissue with RIA.RT-PCR was used to study the gene expression of NF-?B and TNF-?.The proteins of NF-?B p65 and TNF-? were assayed by immunohistochemical method.Results It was showed under light microscope that cardiac myocytes were compact and orderly with clear structure in control group.The cardiac myocytes were disorderly,distorted,with infiltration of inflammatory cells in the interstitium in diabetes group.The cardiac myocytes were orderly arranged,and the structure was close to normality in atorvastatin group.TNF-? in diabetic rats increased significantly in plasma and myocardium(P

Objective To investigate the regulatory effect of fluid shear stress(FSS) on the proliferation and differentiation of osteoblasts,as well as the expression of apoptosis-inducing factor,SIVA-1.Methods The third-passage osteoblasts were divided into five experiment groups and one control group.In the experiment groups,1.2 Pa FSS were given to the osteoblasts for 0.25,0.5,1,2,and 4 hours respectively,while the control group received no FSS.Afterwards,the cells were harvested to measure MTT value and ALP activity;mRNA level of SIVA-1 were determined by RT-PCR.Results MTT revealed that the cells proliferation markedly increased in the 0.25 h and 0.5 h experiment groups with advanced cell growth curve;whereas significantly inhibited in 1,2,and 4 h groups.The FSS also increased the ALP activity at 0.25 and 0.5 hour,especially in the 0.5 h group(2.4320?0.205 S unit/100ml,158% of the control;P

Objective:To investigate affection of ureaplasma urealyticum (UU) infection on the production of calculus of the urinary and reproductive system in male rat. Methods:Sprogue-dawley(SD) rats were infected with UU4 (serotype 4) through repeated natural sexual intercourses for 8 weeks. The urinary and reproductive system were detected . Results:Twelve point five percents of rate infected with UU had soft calculus in urinary tracts, while 27.5 percents of rate infected with UU had soft or hard calculus. Conclusion: Infection with UU may lead to the production of calculus in urinary and reproductive system in male rats

Objective To review an arthroscopic technique using suture fixation for repair of the tibial eminence fractures.Methods A review of 33 patiernts with 11 Meyers and McKeever type Ⅱ,19Ⅲand 3 Ⅳ fractures of the tibial eminence treated with arthroscopic suture fixation were conducted.Results Mean follow-up time was 7 months(range,6 to 12 months).At follow-up evaluation,the range of motion retum to their previous normal levels(rang,0°to 130°).All patients underwent X-ray examination that confirmed the fracture have been healed in 2 months except 2 cases, and pulled out fixation in 12 months.Conclusion The technique of arthroscopic internal fixation of avulsed tibial eminence fractures in 33 cases is very useful in dealing with the fractures in simple fixation,minimal trauma,quick recovery.

Objective To understand the endemic characteristics and regularity of cystic echinococcosis by evaluating and classifying its endemic situation in Non Tibetan Plateau regions,so as to provide the evidence for formulating effective preventive and control measures. Methods The prevalence data of cystic echinococcosis in 174 counties(cities,districts,banners)in Non Tibetan Plateau regions from a national survey were collected and analyzed by the sample cluster method in 2012. Results The 174 counties(cities,districts,banners)could be classified into 4 clusters by spatial distribution. The first cluster with human high prevalence rate,low infection rate of livestock,and positive rate of dog stool antigen included 3 counties. The second cluster with high infection rate of livestock,low prevalence rate of human,and positive rate of dog stool antigen included 20 counties(cit-ies). The third cluster with high positive rate of dog stool antigen,low prevalence rate of human,and low infection rate of livestock included 39 counties(cities,districts,banners). The fourth cluster with low rates of the above 3 indices included the rest 112 counties. Conclusions The results of the cluster analysis conform to the current epidemiological status of cystic echinococcosis in the Non Tibetan Plateau regions. The epidemiological characteristics and geographical distributions of the four area types will pro-vide a basis for the classified management and guidance of cystic echinococcosis control in these areas.

BACKGROUND: Bone marrow mesenchymal stem cells are prospective used in cartilage tissue engineering due to easy acquire and plentiful amplification in vitro in a short term.OBJECTIVE: To summarize the application of bone marrow mesenchymal stem cells in repairing cartilage defect.RETRIEVAL STRATEGY: A computer-based online search was conducted in Pubmed for English language publications containing the key words of "marrow; mesenchymal stem cells; cartilage defect" from October 1982 to December 2006, Relevant data were also searched in China Scientific and Technological Achievement Database for Chinese language publications containing the key words of "marrow; mesenchymai stem cells; cartilage defect" from October 1982 to December 2006. There were 126Exclusion criteria: duplicated articles.LITERATURE EVALUATION: Literatures including reviews and experimental studies were mainly derived from Pubmed database and China Scientific and Technological Achievement Database.DATA SYNTHESIS: It has been proved that bone marrow mesenchymal stem cells could differentiate into cartilage in vivo.However, differentiation of cartilage phenotype in vitro was restricted by multiple factors, and the controlling mechanism is still unclear up to now. Animal experiments demonstrated that bone marrow mesenchymal stem cells could repair bone and cartilage defect. Although studies on bone marrow mesenchymal stem cells and cartilage tissue engineering have developed to a certain degree, clinical applications and evaluations, including cell marks of bone marrow mesenchymal stem cells in different differentiated stages, controls of proliferation and differentiation of bone marrow mesenchymal stem cells, and gene transfection technique, still need a further study.CONCLUSION: Animal experiments indicate that bone marrow mesenchymal stem cells can significantly repair bone and cartilage defect. Although studies on bone marrow mesenchymal stem cells and cartilage tissue engineering have developed to a certain degree, problems of bone marrow mesenchymal stem cells in basic and clinical researches still need to be solved further.

ObjectiveTo investigate the protective effect and mechanism of monosialotetrahexosyl gangliosides ( GM-1 ) on neurons after spinal cord injury (SCI) in rats by observing the effect of GM1 on the expression and motor function of microtubule-associated protein 2 (MAP-2) and Choline acetyltransterase (ChAT). MethodsSixty-six adult female Wistar rats (weighing 260-300 g) were enrolled in the study and six were selected randomly as the normal control group. The rest were divided into GM1 group (group A, n =30) and normal saline control group (group B, n =30) after acute contusion injury was made at T10 level according to the improved Allen's method. At days 1,3, 7, 14 and 28 after operation, the neurological function of the low extremities was assessed with the improved Tarlov scale. Then,the rats were sacrificed to obtain the spinal cord tissues. There were six rats in each group at different time points. The expressions of MAP-2 and ChAT were detected with immunohistochemistry after SCI in rats. ResultsThe improved Tarlov scale in the Group A was higher than that in the Group B after SCI since the 7th day after operation, with statistical difference at day 7, 14 and 28 after operation ( P ＜0. 05). The expressions of MAP-2 and ChAT in the Group A were higher than that in the Group B after SCI ( P ＜ 0.05 ). ConclusionsThe neurological function recovery of the low extremities has some correlations with the expressions of MAP-2 and ChAT after SCI in the rats. GM-1 can protect the neurons by promoting the expressions of MAP-2 and ChAT after SCI.

BACKGROUND: There is still no affirmative conclusion on the proliferative characteristics and the sources of neural progenitor cells after chronic compressive injury of spinal cord in adult mammals and the effects of astrocytes in this process.OBJECTIVE: To investigate the proliferative characteristics and the sources of neural progenitor cell and the effects of astrocytes by means of analyzing the changes of expression of nestin and glial fibrillary acidic protein after chronic compressive injury of spinal cord and after decompression in adult rats.DESIGN: Completely randomized control trial.SETTING: Orthopaedics Research Institute, the Second Hospital of Lanzhou University.MATERIALS: The experiment was completed in Orthopaedics Research Institute of the Second Hospital of Lanzhou University from March to October 2003. A total of 50 adult healthy Wistar rats were selected and randomly divided into normal control group, moderate chronic compressive spinal cord injury group (compressive mass occupied 40% of the diameter of spinal canal), severe compression group (compressive mass occupied 60% of the diameter of spinal canal). Three-day and 10-day decompression groups (depression after 24-hour severe compressive injury) with 10 in each group.MAIN OUTCOME MEASURES: ① Grey value of positive expression of nestin in grey and white matter in spinal cord segment near compression (5 mm to the edge of compression) in rats of each group. ② Expression of glial fibrillary acidic protein in spinal cord of rats in each group.RESULTS: All the 50 rats entered experimental analysis. ①There were significant expressions of nestin in moderate compression group (white matter 235.33±6.48, grey matter 196.28±6.55), severe compression group (white matter 190.45±4.91, grey matter 173.15±5.98), 3-day decompression after severe compressive injury group (white matter 198.39±3.24, grey matter 180.38±4.51) and 10-day decompression group (white matter 202.55±3.54) (P ＜ 0.05), especially in severe compression group (P ＜ 0.01).Compared with the normal control group, the difference between the ex pression of nestin in grey matter and that in ependymal cells on the central canal of spinal cord in 10-day decompression group has no significance (P ＞ 0.05). ②Compared with normal control group, the expression of glial fibrillary acidic protein in spinal cord increased in each injury group,and the amount of positive cells of glial fibrillary acidic protein went up and cell soma was hypertrophic, and the processes became thicker and longer.CONCLUSION: There is neural progenitor cell proliferation in the early stage of chronic compressive injury of spinal cord and after decompression in adult rats. Astrocyte participates in proliferation and migration of neural progenitor cells and has important trophic and repair effects on spinal cord.

Objective To investigate the role of astroglial glutamate-glutamine shuttle in the development of neuropathic pain (NP) in rats. Methods Forty-eight adult male SD rats weighing 200-230 g were randomly divided into 8 groups (n =6 each): Ⅰ control group (group C);Ⅱ sham operation group (group S);group ⅢNP;Ⅳ-Ⅶ 0.01, 0.03, 0.05 and 0.10 mmol/L methionine sulfoximine (MSO, an inhibitor of glutamine synthetase (GS)) group (group M1-4 );Ⅷ MSO + glutaminate group (group MG). In group C no operation was performed. In group S the sciatic nerve was only exposed but not ligated. NP was induced by ligation of the tibial nerve and commom peroneal nerve according to the technique described by Dixon. After the establishment of the model, intrathecal PBS 50 μl was injected in group NP, IT 0.01, 0.03, 0.05 and 0.10 mmol/L MSO 50 μl was injected intrathecally in group M1-4, and 0.05 mmol/L MSO 50 μl was injected intrathecally and then 0.25 mmol/L glutamine 50 μl was injected intrathecally 15 min later in group MG. Mechanical pain threshold was measured 1 week before ligation (T0 , baseline), 1 week after ligation (T1) and 15, 30, 45 and 60 min after injection of MSO (T2-5). Then rats were killed and the lumbar segment of the spinal cord was removed for determination of the expression of glial fibrillary acidic protein (GFAP) and GS and the co-expression (GFAP/GS) in the dorsal horn.Results Mechanical pain threshold was significantly lower at T1-5 in group MG and NP and at T2-4 in group M3.4 ,and the expression of GFAP, GS and GFAP/GS was significantly higher in group MG,NP and M3 than in group S and C ( P ＜ 0.05) .Conclusion Astroglial glutamate-glutamine shuttle in the spinal cord is involved in the development of neuropathic pain in rats.