BACKGROUND:It is wel-known that mechanical stimulation could promote fracture healing. However, what kind of mechanical stimulation induced by treadmil exercise can increase the bone conductibility of bone material and promote the healing of bone defect is stil unclear.
OBJECTIVE:To evaluate the influence of indirect mechanical stimulation produced by treadmil exercise on bone defect healing and osteogenesis of bone materials.
METHODS:Sprague-Dawley rats at 12 weeks old were used in this study to establish a bone defect of 3 mm in diameter and height at the left distal femur. Afterwards, calcium sulphate scaffolds were implanted into the defects. The rats were divided into treadmil exercise group and control group. Treadmil exercise was began at 1 week postoperatively, 10 m/min, 45 minutes per day, 5 days per week, for 3 weeks. Control group did not receive any exercise. Micro-computed tomography was used to determine bone formation in the bone defects at 1, 2, 3, and 4 weeks after surgery. The sections of left distal femur were subject to hematoxylin-eosin staining, the new bone formation and degradation of bone materials in the bone defects were observed.
RESULTS AND CONCLUSION:Micro-CT analysis showed that, a smal amount of new bone formed in both treadmil exercise group and control group at 1 week after surgery. In treadmil exercise group, new bone formation was significantly higher than the control group at 2, 3, 4 weeks (P<0.05). At 4 weeks, histological results also confirmed the difference of new bone formation in bone defect between treadmil exercise group and control group. In addition, bone mineral density of treadmil exercise group was higher than that of control group at 2, 3, 4 weeks, but no significant difference was found (P>0.05). The results suggest that moderate treadmil exercise could promote bone defect healing and enhance osteoconductivity of bone substitute.

BACKGROUND:Different mechanical stimulations may have an effect on the level of metabolism of chondrocytes, but the effect is not clear.
OBJECTIVE:To investigate expression level changes in metabolic genes that participate in cartilage cel decomposition and synthesis under compressive stress and tensile stress conditions.
METHODS:We obtained articular chondrocytes from 2-week-old Sprague-Dawley rats. Primary cultured chondrocytes were identified. Passage one chondrocytes received cyclic tensile stress and cyclic compressive stress of 3%and 7%, respectively, so as to measure articular changes in chondrocytes-related genes.
RESULTS AND CONCLUSION:When chondrocytes were subjected to cyclic tensile stress of 3%, synthetic metabolic gene col agen types I and II and proteoglycan mRNA expression levels were decreased. If 3%cyclic compressive stress was applied, proteoglycan mRNA expression levels were increased, and type I col agen mRNA expression levels were decreased (P<0.001), and matrix metal oproteinase-13 mRNA expression levels were reduced (P<0.01). When strain reached 7%, cyclic tensile stress and compressive stress could lead to a general decrease in anabolism-related genes. The former could also make matrix metal oproteinase-13 mRNA expression levels increased (P<0.05). 3%cyclic compression ratio and 3%cyclic stretch made cytoskeleton become oval. These results indicated that in vitro, proper cyclic compressive stress is beneficial to maintain the growth characteristics of articular chondrocytes in rats. Smal tensile stress can decrease the synthesis ability of chondrocytes. The effect of stress may be caused by changing the cytoskeleton.

AIM: To investigate the effects of propofol on the expression of tissue-type plasminogen activator (tPA) and matrix metalloproteinase 9 (MMP9) in the hippocampus and the cognitive function in neonatal rats.METHODS: The 7-day-old rats were randomly divided into 3 groups: the rats in control (CON) group were intraperitoneally injected with normal saline for 7 d;the rats in single dose of propofol anesthesia (SP) group were intraperitoneally injected with normal saline for 6 d and with propofol on the 7th day;the rats in repeated dose of propofol anesthesia (RP) group were intraperitoneally injected with propofol for 7 d.Blood glucose and blood gas analysis were tested in 6 rats of each group.The rats were randomly selected from each group to isolate the hippocampal tissues at 2 h, 24 h, 48 h, 72 h and 30 d after the last injection.The spatial learning and memory functions of the other rats aged 25 d were determined by Morris water maze.The morphological changes of the hippocampus were observed by HE staining and Nissl's staining.The expression of tPA and MMP9 at mRNA and protein levels was determined by RT-PCR and Western blot.RESULTS: Compared with group CON, the protein expression of tPA and MMP9 in RP group was significantly decreased at each time point, while no significant decrease was observed in SP group except at the time point of 24 h.Compared with CON group, the mRNA expression of tPA and MMP9 was down-regulated obviously in RP group, which was not significantly down-regulated in SP group.From the 3rd training day of Morris water maze beginning, the escape latency was prolonged, and the space exploration time and the number of crossing the original platform location were reduced in RP group compared with CON group and SP group, while no significant difference was observed between CON group and SP group.Compared with CON group, the number of nerve cells reduced and nerve cells arranged in disorder in the hippocampus in RP group.Moreover, the number of Nissl body decreased significantly and finally developed into neuronal degeneration and necrosis in RP group, and no significant difference between SP group and CON group was observed.CONCLUSION: Repeated dose of propofol anesthesia leads to long-term cognitive dysfunction in neonatal rats, which may be related to the down-regulation of tPA and MMP9 expression and destruction of normal morphology and function of neurons in hippocampus, whereas single dose of propofol anesthesia has no such effects.

Aim To observe the improvement effects of parecoxib on ventricular remodeling after acute myocardial infarction in rats and its influence on PI3K/Akt signaling pathway.Methods Forty male Sprague-Dawley rats were randomly divided into five groups(n=8):sham operation group (group S), ventricular remodeling model group(group R), low dose of parecoxib group(group P1), middle dose of parecoxib group(group P2), and high dose of parecoxib group(group P3).A myocardial infarction model was established by ligating the left anterior descending branch(LAD) of coronary artery in group R, group P1, group P2 and group P3.One day after the operation,the rats were given intraperitoneal injection of 4,8,12 mg·kg-1 parecoxibin Group P1, group P2 and group P3,respectively, for two weeks.The same volume saline was given in group S and group R.Four weeks later, LVSP, LVEDP,+dp/dtmax,-dp/dtmax were monitored.The hearts were harvested to calculate left ventricular hypertrophy index.The pathological change of heart was examined with an optical microscope.The expressions of atrial natriuretic peptide(ANP) mRNA and brain natriuretic peptide(BNP) mRNA were detected by RT-PCR.The expression of PI3K,Akt,P-Akt and caspase-3 was detected by Western blot.Results Compared with group S, the cardiac function was decreased, the left ventricular hypertrophy index, the expression levels of ANP,BNP mRNA, caspase-3 were increased, and the expression levels of PI3K, P-Akt were reduced in group R(all P<0.05).Compared with group R, the cardiac function was ameliorated, the left ventricular hypertrophy index were reduced in group P2 and group P3(all P<0.05).The expression levels of ANP,BNP mRNA, Caspase-3 were decreased, and the expression levels of PI3K and P-Akt were increased in group P1,group P2 and group P3(all P<0.05).Conclusions Middle and high doses of parecoxib can mitigate the process of ventricular remodeling after myocardial infarctionand improve the myocardial function, and its underlying mechanism may be related to activating PI3K/Akt signaling pathway.

Aim To investigate the role of matrix metalloproteinase-9 down-regulation in the learning and memory dysfunction induced by propofol treatment in rats.Methods 7-day-old SD rats were randomly divided into three groups(n=18):control group(NS group) and repeated doses of propofol group(RP group) was intraperitoneally injected with normal saline and propofol respectively for consecutive seven days, single dose of propofol group(SP group) were intraperitoneally injected with normal saline first for consecutive six days, and then injected with propofol on 7th day.The blood gas and glucose levels were monitored of six rats randomly selected from each group.Morris water maze was conducted to test the learning and memory functions of the remaining rats.The expression of MMP-9, BDNF and caspase-3 was detected by Western blot, and the hippocampal neuron apoptosis was determinated by TUNEL staining.Results Compared with NS group and SP group, the escape latency in RP group was prolonged significantly, exploration time and the number of crossing the platform in RP group were markedly decreased(P<0.05).The expressions of MMP-9 and mBDNF in RP group declined, but the expression of proBDNF and the ratio of proBDNF/mBDNF in RP group were higher than those in NS group and SP group(P<0.05).Compared with NS group and SP group, the number of apoptotic neurons and the expression of cleaved-caspase-3 in RP group were increased significantly, but the expression of pro-Caspase3 in RP group was reduced(P<0.05).There was no difference between SP group and NS group regarding all the results(P>0.05).Conclusions Repeated exposure to propofol can lead to a decline in long-term learning and memory functions in neonatal rats, which may be related to the down-regulation of MMP-9 expression, proBDNF and mBDNF conversion disorder in hippocampus and the apoptosis of hippocampal neurons.However, single exposure to propofol has no significant effect.

Objective To study the expression of hypoxia inducible factor-1alpha (HIF-1α) mRNA in re-nal tissue after renal ischemia-reperfusion injury (IRI), and to investigate the effect of hyperbaric oxygen (HBO) on renal IRI and its mechanism. Methods Forty-two Wistar rats were randomly divided into a normal control group(n =6), a renal IRI group (n=18) and an HBO treatment group (n=18). Renal IRI models were established in all the rats. The plasma levels of Cr in the experimental groups were then measured after 1, 3 and 5 hours. The expres-sion of HIF-1α mRNA was also detected using real-time PCR and immunohistochemistry. Kidney tissue sections were preserved for ultrastructure examination. Results (1) The average levels of plasma Cr in the renal IRI group were significantly higher than those in the control group. Compared with the renal IRI group, plasma Cr was significantly lower in the HBO treatment group. (2) The average expression of HIF-1α mRNA was significantly lower an hour after reperfusion, but significantly higher after 3 hours than in the control group. There was no significant difference by the 5th hour after reperfusion. In the HBO treatment group, HIF-1α mRNA was up-regulated significantly at the 1st and 3rd hour after reperfusion compared with the renal IRI group, but it was reduced significantly by the 5th hour after reperfusion. (3) The severity of the kidney injury increased gradually with time in the renal IRI group. After HBO treatment, however, the damage to the renal tissues decreased significantly. Conclusions HIF-1α mRNA plays an important role in the development of renal IRI. The damage to renal tissues and renal function improves significantly after reperfusion and HBO treatment through earlier priming and up-regulating of HIF-1α mRNA expression. HBO should be applied early to help prevent renal IRI.

Objective To evaluate the efficacy of partial cystectomy in treatment of localized muscle invasive bladder cancer.Methods From 1999 to 2005,data from 71 patients with muscle invasive bladder cancer(MIBC) were reviewed.There were 47 patients underwent partial cystectomy (PC) and 24 underwent total cystectomy (TC).The overall survival and disease-free survival in patients with MIBC with PC or TC were compared.All patients had pathologic T2-T3.Matched Kaplan-Meier survival analyses compared the effect of PC vs.TC on overall survival and disease-free survival.Univariate (log rank) and multivariate (Cox' proportional hazard model) analyses were used to test the statistical significance of several potential prognostic factors for survival rate.Results In the entire cohort,the overall survival rate and disease-free survival rate estimated at 5 years were 57％ and 50％ for PC patients,53％ and 46％ for TC patients,respectively (P＞0.05).On univariate analysis,T stage (include vessel tumor embolus) and whether the tumor was pedunculated were the significant predictors of tumor recurrence.Age,gender,tumor quantity,tumor size and histology category were not associated with prognosis.Cox proportional hazard regression model confirmed that the independent prognosis factors of tumor was T stage (EXP(B)=1.64,P＜0.05).Conclusions PC might not undermine cancer control in appropriately selected patients with MIBC.

Objective In order to study the biological characteristics of macrophages and provide the materials to study the survival mechanism of intracellular parasites, we conducted this study to establish a high-purity alveolar macrophage isolation and culture method.Methods Goat lungs were lavaged with normal saline in sterile environment several times, and cells were collected and then goat alveolar macrophages were purified by density gradient centrifugation using peripheral blood mononuclear cells (PBMC) solution.The isolated goat alveolar macrophages were cultured in cell culture medium containing 10% fetal bovine serum and cell morphology was observed under an inverted microscope every day,and the phagocytic activity of the cells was detected by chicken red blood cell phagocytosis test.Flow cytometry was used to detect CD14, a characteristic monocyte-macrophage surface marker.Results The adherent cells were characterized by typical macrophage morphology, pseudopodia and protrusions, showing round and irregular shape, rich cytoplasm, and large cell body.Of the cultured macrophages, 54.5% could phagocytize chicken erythrocytes and showed good phagocytic activity.After one month of in vitro culture, 93.7% of the cells were able to express CD14 antigen, which had a macrophage-specific immunophenotype.Conclusions The alveolar macrophages obtained in this study have high purity and good bioactivity, thus provide a cell model for studying the immune mechanism of intracellular parasites.

Objective To evaluate the predictive value of tumor metabolic indexes measured by 18F-FDG PET/CT in recurrence of stage Ⅰ NSCLC after surgery.Methods A total of 85 patients (44 males,41 females,age (62.46± 10.38) years) in Shanghai Renji Hospital with stage Ⅰ NSCLC,who underwent 18F-FDG PET/CT and subsequent surgical resection,were retrospectively enrolled from April 2006 to December 2011.Gender,age,tumor size,pathology,SUVmax,MTV and TLG of the primary tumor were selected as variables.ROC curve analysis was used to analyze the cut off value.The prognostic significance of parameters for recurrence-free survival (RFS) was evaluated by univariate and multivariate analyses.Survival analysis was analyzed by Kaplan-Meier method.Results During follow-up period,tumor recurrence occurred in 21 patients (24.7％,21/85) and 11 patients (12.9％,11/85) died.The median follow-up period was 44 months.The median values of SUVmax,MTV and TLG were 4.100,3.048 cm3 and 7.970,respectively.Cut off values of SUVmax,MTV and TLG were 7.115,4.701 cm3 and 12.015 according to ROC curve analysis.Univariate Cox analysis showed that SUVmax(x2 =22.091),MTV (x2 =4.941) and TLG(x2 =10.488) were associated with RFS(all P＜0.05).But gender,age,tumor size,and pathology were not independent risk factors of recurrence (x2=0.248-3.888,all P＞0.05).Multivariate Cox analysis revealed that SUVmax(=16.902,HR=15.426,P＜0.05) and TLG (x2=6.029,HR=4.054,P＜0.05) were independent prognostic factors for recurrence.Kaplan-Meier survival analysis showed that the period of RFS in high SUVmax (＞ 7.115) group (x2=32.545,P＜0.05) and in high TLG (＞12.015) group (x2=12.665,P＜0.05) were lower than those in low SUVmax group and low TLG group.Conclusion The SUVmax and TLG measured by 18F-FDG PET/CT have significant value for predicting the recurrence of stage Ⅰ NSCLC.

Objective In this paper,we analyzed the initial review projects of clinical research during past five years in a hospital,which aims to summarize the experience and analysis existent problems,in order to provide a reference for the future hospital ethics review.Methods Summarizing and analyzing the meeting records during past five years,which were also in the field of the initial review projects of clinical research.Results Clinical trials of drug and divice,and clinical research projects exist in varying degrees of problems,which express in these two aspects:research design and ethical rational.Conclusions Ethics Committee should stengthen review the following two parts,the scientific of research project and the informed consent form.Improve their own system constantly,and ensure the efficient operation of the Ethics Committee.