Objective To construct the third-generation self-inactivating lentiviral vectors including BMP-2,BMP-4,BMP-6,BMP-7,BMP-9 and Wnt3a,then integrate them into the genome of mouse embryonic osteoblast cell,MC3T3-E1,and to explore the capability of osteogenic differentiation of individual bone morphogenetic control factor and the effective approaches to further improve the capability of osteogenic differentiation.Methods The plasmid vectors of gene expression including BMP-2,BMP-4,BMP-6,BMP-7,BMP-9 and Wnt3a were constructed,which were identified through enzyme cutting and further confirmed through sequencing.After packing pELNS-BMP-2,BMP-4,BMP-6,BMP-7,BMP-9 and Wnt3a,mouse embryonic osteoblast cell,MC3T3-E 1 was transfected,and the transfection efficiency was confirmed by GFP fluorescence imaging.The expression level of Runx2 mRNA and the transfection efficiency of individual bone morphogenetic control factor was detected by Real time PCR.Eight groups of MC3T3-E1 were dual-gene co-transfected,and the transfection efficiency was verified by GFP fluorescence imaging.ELISA was adopted to detect the expression level of BGP and ALP in MC3T3-E1culture supernatants;Real time PCR was adopted to detect the expression level of Runx2 mRNA;Western blot was adopted to detect the expression level of protein of BMP-2,BMP-4,BMP-6,BMP-7,BMP-9 and Wnt3a.Thus,the effectiveness of osteogenic differentiation of dual-gene co-transfection were evaluated.Results The recombination of lentiviruses,pELNS-BMP-2,pELNS-BMP-4,pELNS-BMP-6,pELNS-BMP-7,pELNS-BMP-9 and pELNS-Wnt3a were successfully constructed.MC3T3-E1 was successfully transfected.The expression levels of Runx2 mRNA were:BMP-2 ＞ BMP-4 ＞ BMP-9 ＞ BMP-7 ＞ Wnt3a ＞ BMP-6.Successful transfection of the dual-gene co-transfection of eight groups of MC3T3-E1 were verified by GFP fluorescence imaging.The expression level of Runx2 mRNA,the expression of BGP and ALP showed BMP-2 and BMP-7 co-transfection group was the most efficient in osteogenesis transfection.Western blot revealed thatthe protein expression of BMP-2,BMP-4,BMP-6,BMP-7,BMP-9 and Wnt3a increased after cotransfection of MC3T3-E1 by BMP-2 and BMP-7.Conclusion The third-generation lentiviral vector,pELNS can lead BMP-2,BMP-4,BMP-6,BMP-7,BMP-9 and Wnt3a into MC3T3-E1,mouse embryonic osteoblast cell,and stabilize its expression.Individual bone morphogenetic control factors can promote MC3T3-E1's differentiation to osteoblasts.The dual-gene co-transfection of BMP-2 and BMP-7 can effectively promote osteoblast conversion,which provides significant theoretical basis and technical support for remodeling of tissue engineering bone.

This paper discussed the roots of American ethical review system, the development of twists and turns, and puts forward the enlightenment to our country, the ethical review system mainly include:perfecting the ethical review at the top of specification design, improve specification status;improve the system of education and training, to strengthen the construction of information communication channels, establish standard operating proce-dures, improve the regulatory system;improve the system of continuous review, formulate specific implementation specification.

Objective To evaluate effects of chronic arsenic exposure and arsenic exposure time on oxidative DNA lesions in humans. Methods A cross-sectional study was conducted in 108 subjects exposed to high concentrations of arsenic in drinking water and 75 control subjects. A cohort study was conducted in 64 subjects exposed to high levels of arsenic in drinking water for 7 or 9 years. Urinary 8-oxo-7,8-dihydredeoxygnanine(8-OHdG) levels were analyzed by the enzyme-linked immunosorbent assay kit(ELISA). Urinary arsenic concentration was detected with hydride generation atomic absorption spectroscopy. Results In the cross-sectional study, the median of urinary arsenic concentration was 484.17 mg/kg Cr for the arsenic-exposed group, and 13.80 mg/kg Cr for the control group, and the difference between the two groups was statistically significant (t=32.57, P<0.01). The median of urinary 8-OHdG levels was 16.60 and 21.88 mg/kg Cr for arsenic-exposed children and adults respectively, much higher than control children(10.50 mg/kg Cr) and adults (9.11 mg/kg Cr), and the difference was statistically significant (t=5.049, 6913, all P<0.01). Urinary 8-OHdG levels were signifieandy lower for children than adults in the exposed group(t=-1.997, P<0.05). In the cohort study, the median of urinary arsenic concentration was 461.3 mg/kg Cr for the 7-year-exposed subjects and 422.90 mg/kg Cr for the 9-year-expesed subjects, and no significant difference was observed(t=-0.250, P 0.05). The median of urinary 8- OHdG levels for 9-year-exposed children and adults were 23.46 and 24.30 mg/kg Cr respectively, significantly increased compared with those of 7-year-exposed(14.29 and 18.38 mg/kg Cr), and the difference had statical signhqcanees (t= -2.949,-3.055, all P<0.01). Conclusions Chronic arsenic exposure can lead to oxidative DNA lesions in humans. The arsenic-induced DNA lesions may aggravate with the exposure time in a certain period.

Objective To investigate the effects and mechanisms of 1,25-Dihydroxyvitamin D3 [1,25(OH)2 D3] on hyperoxia-induced lung injury of neonatal rats.Methods Neonatal Sprague-Dawley rats were randomly divided into air group,hyperoxia group and 1,25(OH)2D3 group within 12 hours after birth,eight in each group.Rats in air group were exposed to air,while those in hyperoxia and 1,25 (OH) 2 D3 group were exposed to hyperoxia (≥85 ％ oxygen concentration).Rats in 1,25(OH)2D3 group were injected with 1,25(OH)2D3 0.5 μg/(kg · d) intraperitoneally once a dayfor seven days,meanwhile the rats in the other two groups received 0.9 ％ saline in the same way.All rats were sacrificed on day 7.Lung tissue sections were HE stained in order to assess lung histological changes and lung radical alveolar count (RAC).The levels of tumor necrosis factor-α(TNF-α),interleukin(IL)-1β and IL-6 mRNA were measured by real time-polymerase chain reaction.Analysis of variance and LSD test were applied for statistics.Results Compared with the air group,the weight of rats in the hyperoxia group was significantly lower on day 7 [(8.48±1.34) g vs (12.51±0.47) g,t=8.05,P＜0.05],while the weight of rats in 1,25(OH)2D3 group [(10.29±1.00) g] was higher than that in the hyperoxia group (t=3.61,P＜0.05).Lung tissue structure was normal in the air group.In the hyperoxia group,inflammatory exudation was observed in pulmonary interstitial,the alveolar size was uneven,and the RAC was lower than that in the air group (5.6±0.1 vs 6.8±0.2,t=21.45,P＜0.05).The RAC in 1,25(OH)2D3 group (6.2±0.1) was significantly increased compared with that in the hyperoxia group (t=11.76,P＜0.05),but still lower than that in the air group (t=9.69,P＜0.05).The expressions of TNF-α,IL-1β and IL-6 mRNA in hyperoxia group (0.0348±0.0006,0.0269±0.0003 and 0.0368 ± 0.0006) were higher than those in the air group (0.0111±0.0007,0.0040±0.0003 and 0.0162 ±0.0007,t=56.54,111.12 and 49.26,P＜0.05,respectively).The expressions of TNF-α,IL-1β and IL-6 mRNA in the 1,25 (OH)2D3 group (0.0203±0.0009,0.0141±0.0004 and 0.0251±0.0009) were lower than those in the hyperoxia group (t=34.44,61.93 and 27.99,P＜0.05,respectively),but higher than those in the air group (t=22.10,49.19 and 21.27,P＜0.05,respectively).Conclusions 1,25(OH)2D3 could attenuate hyperoxia-induced lung injury by inhibiting the expression of inflammatory cytokines.

Objective To apply 3C3R model in problem design of PBL for pediatrics teaching.Methods The 3C3R model comprises two classes of components:core components and processing components.Core components of the model are 3C,which are content,context and connection while processing components are 3R,which are researching,reasoning and reflecting.3C3R model was used in the problem design for the PBL case of ‘ Why the mouth of Baobao became purple when he was crying?' Totally 76 eight-year program medical students and 7 tutors were enrolled as teaching object.The anonymous questionnaires from the students were collected for assessment of PBL teaching.Results The percentage of students with scores ≥4 for content in PLB problem design was 90.8％,for context was 80.3％,for connection was 64.5％,for researching was 81.6％,for reasoning was 69.7％ and for reflecting was 40.8％.The percentage of tutors with scores ≥4 for content in PLB problem design was 100％,for context was 71.4％,for connection was 28.6％,for researching was 71.4％,for reasoning was100％,for reflecting was57.1％.Both students and tutors held a positive attitude towards the component of content,context,researching and reasoning in problem design model.But the components of connection and reflection needed to be improved.Conclusion The 3C3R model is helpful for problem design of PBL in pediatric teaching.

Objective To explore the surgical strategies of thoracic spinal stenosis with dural ossification. Methods One-hundred and eight patients with thoracic spinal stenosis were treated. Dural ossification was found in 29 cases during operation from January 2004 to June 2008. There were 19 males and 10females, with an average age of 56.4 years (42-74 years). The course of disease was 13 months (2-48months). The lesion was located in T1-T4 in 4 cases, T5-T8 in 5 cases, and T9-T12 in 20 cases. All the patients were treated by posterior lamina resection. Both ossificated dural and ossificated yellow ligament were resected in 16 patients. Decompression was performed with partial ossification remaining on dural surface in 13 cases. JOA score was used to evaluate the outcomes 1, 3 and 12 months after operation. Results The average operation time was 140 min, and average bleeding was 300 ml. Dural incisions were repaired with a wound drainage in 11 cases. Seven cases appeared cerebrospinal fluid leakage which healed in 3-5 days.Dural incisions were not repaired without wound drainage in 5 cases. Cerebrospinal fluid leakage occurred in these cases healed in 5-7 days. Thirteen cases treated with floating method did not appear cerebrospinal fluid leakage. All patients did not undergo subarachnoid infection and the aggravation of original nervous system symptoms. According to JOA score, all patients were evaluated as excellent in 22 cases, good in 5 and fair in 2 cases, and excellent and good rate was 93%. Conclusion For thoracic spinal stenosis with dural ossification, resection of both ossificated dural and ossificated yellow ligament and complete decompression with partial ossification remaining on dural surface is safe and reliable. Dural ossification does not influence the prognosis, but increase operative difficulty and risk.

Objective To study the clinical features and surgical strategies of thoracic spinal stenosis caused by ossification of posterior longitudinal ligament(OPLL).Methods From January 2004 to March 2009,21 cases of thoracic spinal stenosis casued by OPLL,including 13 males and 8 females,received surgical treatments.Those cases aged from 34 to 71 years,with an average of 51.2 years old.The courses of disease were from 2 to 50 months,averaged 11 months.The lesions located in upper thoracic(T1-T4)for 4 cases,in middle thoracic(T5-T8)for 7 cases,in lower thoracic(T9-T12)for 10 cases.Nine cases were associated with ossification of ligamentum flavum(OLF),and 8 cases combined with cervical OPLL.Eleven cases received laminectomy and 10 cases received anterolateral decompression.Results The operation time was 90 to 240 min for posterior laminectomy with an average of 140 min,and 110 to 360 min for anterolateral decompression with an average of 240 min.All cases had no worse postoperative symptoms,neurological complications,subarachnoid cavity or wound infection.Japanese Orthopaedic Association(JOA)score was 8 to 15 with an average of 9.17±1.63 in 6 months after surgery.Nerve function improvement was excellent for 8 cases,good for 6 cases,fair for 5 cases and poor for 2 cases.The excellent and good rate was 66.7%.JOA score was 8-15,averaged 10.23±1.64,in 12 months after surgery.Nerve function improvement was excellent for 8 cases,good for 7 cases,fair for 4 cases,and poor for 2 cases.The excellent and good rate was 71.4%.Conclusion Thoracic spinal stenosis result from OPLL,which often combine with cervical OPLL and OLF,often show multiple manifestations.Posterior laminectomy and anterolateral decompression are suitable for those conditions.

AIM :To investigate the association of primary open-glaucoma (POAG), intraocular pressure (IOP) and systemic blood pressure in a rural population aged 50 years old or above in Shaanxi Province, China.METHODS: In the population-based, cross-sectional study, 1 775 (83.53%) residents, aged 50 years old or above, from 3 counties of Shaanxi Province, China, undertook an interview with a standard questionnaire and a detailed eye examination, including logarithm of the minimum angle of resolution visual acuity, slit-lamp biomicroscopy, applanation tonometry and dilated fundus examination. Two blood pressure reading in the sitting position were taken. Gonioscopy was performed if a narrower peripheral anterior chamber (less than one fourth of the corneal thickness) was indicated. Automated visual field testing was performed by participants assessed to have suspicion of glaucomatous disc damage or if IOP was 22mmHg or higher.RESULTS: IOP significantly correlated with systemic blood pressure, and both IOP and systolic blood pressure increased significantly with increasing age. No association between POAG and hypertension was found. The frequency of POAG increased significantly with lower diastolic perfusion pressure.CONCLUSION: Data in our study are accordance with those reported in other population-based studies, and confirm that lower diastolic perfusion pressure is a significant risk factor for primary open angle glaucoma.

AIM: To assess the prevalence and risk factors for age-related macular degeneration (AMD) in a rural population in Shaanxi Province of China.METHODS: A total of 2 835 (81.00%) people aged 40 years old or more, from Fuping county, Jingbian county and Yang county of Shaanxi Province, China, underwent a comprehensive interview and a relative eye examination. The present of AMD was classified into neovascular AMD (NV) and pure geographic atrophy (GA) by using direct ophthalmoscopy for fundus examination according to International Classification System.RESULTS: The prevalence (95% CI) of AMD was 3.00% (2.42, 3.71) in this population, of which NV accounted for 1.45% (1.05, 1.98) and 1.55% (1.14, 2.10)for GA. The prevalence of AMD increased significantly with increasing age (P ＜0.001). AMD was present in 0.47% of participants aged 40 to 49 years, rising to 11.90% of participants older than 80 years, of which the corresponding data increased from 0.28% to 4.76% for NV and from 0.19% to 7.14% for GA. No significant difference was found in the prevalence of NA and GA between genders in this population. With multiple logistic analyses, apart from advancing age, only smoking was found to have a strong association with any type of AMD.CONCLUSION: The prevalence of AMD in the rural population of Shaanxi Province of China is lower than that reported from other population-based studies in different provinces of China, less than that reported in whites, more than that reported in blacks. Except increasing age, smoking is also a significant well-known risk factor for AMD.

· AIM: To assess the prevalence and related risk factors for primary angle-closure glaucoma in a rural population for 40 years of age or older in Shaanxi Province.· METHODS: By using a stratified, cluster-based, random sampling technique, 8 500 persons of all ages were selected randomly, including 3 500 those aged 40 years or more, from the North, the South and the Middle of Shaanxi Province in Western China from July to December in 2003. All participants had an interview with a standard questionnaire and those questions related to glaucoma of previous diagnosis and treatment, family history and outbreak history. Then a detailed and relative eye examination was performed, including logarithm of the minimum angle of resolution visual acuity, external eye examination with slit-lamp biomicroscopy and fundus examination. The intraocular pressure was measured with Perkins applanation tonometry to those persons aged 50 years old or more and those with suspected increased IOP. A further examination was performed to those persons with suspicious glaucoma, including repeated tonometric examination, gonioscopy, dark room test, automated visual field testing, et al.·RESULTS: 6 815 of the eligible 8 500 persons of all ages were interviewed and examined from July to December in 2003, a response rate of 80.18%, including 2835 of the eligible 3 500 persons of 40 years old or more with a response rate of 81.00%. According to Van Herick method, the percentage of shallow peripheral anterior chamber was 13.6%, of which 10.4% was in grade 2, 3.0% in grade 1, and 0.2% in grade 0. In this rural population for 40 years of age or older 31 participants were found to have primary angle-closure glaucoma, with the prevalence of 1.09%. With multiple logistic analyses, the prevalence increased significantly with age (P=0.008), whereas no significant difference (Pgender=0.180, Peducation=0.199) was found in the rate with gender and education, although women and illiteracy seemed to be at increased risk of the disease (OR: 1.77, 95%CI,0.77-4.10; OR: 1.71, 95%CT, 0.76-3.87). Of 31 participants, 21 persons (67.74%) had not been previously diagnosed and treated. Of 10 participants previously diagnosed, 6 (60%) had been received peripheral iridectomy; nevertheless, no any other treatments were performed. 48.39% participants suffered from visual impairment in various degrees, of which the percentage of blindness in either eye accounted for 29.03%. Of those with primary angle-closure glaucoma, 22 persons (70.97%) were classified as having chronic from of the disease.· CONCLUSION: In this rural population in Shaanxi Province of China, the rate of occludable angles is 13.6%, more common than that reported previously in other Chinese populations. The prevalence of primary angle-closure glaucoma is close to that from other Asian populations, increasing with age. A majority of glaucoma was undiagnosed and untreated previously.