BACKGROUND: Researches on vitodynamics present that percutaneous vertebroplasty (PVP) can strengthen hardness and intension of single osteoporosis vertebral body after injection of bone cement; however, the infused volume and site of bone cement for maintaining mechanical stability of vertebral body should be further studied.OBJECTIVE: A numerical calculation method on finite element models (FEM) for biomechanical analysis has been developed, while a boundary condition describing the relative L1 -L2 displacement is imposed on the FEM to account for three-dimensional physiological states.DESIGN: Non-randomized control study.SEITING: Beijing Neurosurgical Institute.MATERIALS: One female patient aged 54 years with compressibility fracture at lumbar vertebrae L1-L2 induced by osteoporosis was diagnosed with CT examination, and the patient was told the fact. Based on CT scanning before and after PVP, 90 serial sections with the thickness of 1 mm were obtained and the size of each pixei was 0.33 mm.METHODS: The experiment was carried out Beijing Neurosurgery Institute from October 2005 to June 2006. ①Establishment of three-dimensional FEM: Integrating the anatomical structure from the spine CT and MRI image of a patient, a novel three-dimensional geometric model of lumbar functional spinal units (FSUs) has been built. Meanwhile, 90 serial sections were obtained to exchange data of CT sections and divide imagings. Based on the geometric model, two kinds of three-dimensional FEM of L1-L2 segments for preoperative and postoperative vertebrae were created. ② Model evaluation: The lcad of (500 N, 1 000 N, 1 500 N, 2 000 N, 2 500 N) axial compression were applied to the superior surface of the model in the form of a uniformly concentrated lcad over all L1 superior surface nodes respectively. We could observe the stress distribution of L1-L2 segment by applying the load and clue on the high stress concentration region as the most likely areas fracture.MAIN OUTCOME MEASURES: ① Changes of displacement, stress and strain distributions of FEM at L1-L2 segment of lumbar vertebrae under various loads; ② Effect of increase of bone cement volume on displacement, stress and strain distribution.RESULTS: ① The increase in displacement, stress and strain of FE model with the increase of loading in the postoperarive cases. The tendency was approximately linear which also illustrates the spine have flexible biomechanical characteristics. The region was a common place for injures due to loading. The magnitude of stress in the intervertebral disc depended on the proportion of load applied to the superior surface of the motion segment. The heavier the lcad was, the stronger the stress was. ② With the increase of stress on intervertebral disc, the increasing volume of bone cement could induce transfusion of load of nearby vertebral body.CONCLUSION: Building three-dimensional FEM of L1-L2 segments for preoperative and postoperative PVP can explain three-dimensional physiological status of vertebral body based on calculating relative shift of L1-L2 segment of lumbar vertebrae. Meanwhile, simulative calculation can clearly express distribution of stain and stress and preoperative and postoperative deformity of vertebral body.

Objective To explore the effect of psychological resilience and mood on mental health of leftbehind children.Methods Positive and Negative Affect schedule (PANAS),the Resilience Scale for Chinese Adolescent (RSCA) and Mental Health Scale of Middle School Student (MSSMHS) were administrated to 796 left-behind children.Results ①Positive/negative emotions could significantly predict psychological resilience (β=0.875,P＜0.01 ; β=-0.713,P＜0.01).②Psychological resilience had significantly negatively forecast mental health (β=-0.759,P＜0.01).③The relationship between negative affect and mental health was partially mediated by psychological resilience (P＜0.01).The relationship between positive affect and mental health was completely mediated by psychological resilience.Conclusion Psychological resilience plays an important role in the relationship between positive/negative emotions and mental health.Positive affect can improve mental health of left-behind children through psychological resilience.

Objective To understand the basic circumstance of the hospital infection,and to improve the knowledge of medical staff on the management of hospital infection.Methods With bedside observation and examination combined with checking clinical case history,462 inpatients were investigated on current rate of hospital infection and its related factors.Results There were 30 inpatients suffering from hospital infection,the current rate of the hospital infection was 6.49 %;among them,the rate of the lower respiratory tract accounted for 33.00%.The current rates of hospital infection in inpatients with antibiotics(16.56%),or with treatment of urinary catheters(18.52%),or with operation(16.30%),with more than one month hospitalization(19.05%) were significantly higher than those of inpatients without antibiotics(1.00%),without treatment of urinary catheters(5.75%),without operation(4.05%) or with less than one month hospitalization(4.55%)(all P

Objective To investigate possible reasons of different incidence of femoral head necrosis between two populations exposed to corticosteroid: severe acute respiratory syndrome (SARS) and renal allograft transplantation. Methods 67 cases of SARS and 59 cases of renal allograft transplantation were enrolled in the study. The following relevant data were reviewed: cumulative dosage (intravenous methylprednisolone and oral prednisone respectively), maximum single dosage, corticosteroids-exposing days, body weight, weight-load index, and minimum arterial oxygen pressure. MRI of bilateral hips was taken in all the patients. Results The incidence of femoral head necrosis of SARS (23.9%) was significantly higher than the renal allograft transplantation patients (6.8%) (P0.05). There was a very significant difference in minimum arterial oxygen pressure between two groups (P

Objective:To investigate the enhancing effect of bone marrow stroma cell(BMSC)on the functional recovery of injured spinal cord by observing the formation of gliotic scar,cavity volume and the cascade of apoptosis of neural cells.Methods:Eighty spinal cord injury(SCI)rat models were made and randomly divided into two groups:group A(n=40),the control group without any treatment;group B(n=40),the injured animals treated with BMSC implantation.The behavioral evaluation was performed using Basso,Beattie and Bresnahan(BBB)scoring system.Scores were recorded at time points of 1,2,4,6 and 8 weeks after transplantation.After 8 weeks,rats were sacrificed.The immunoreactivity of Nogo-A,glial fibrillary acidic protein(GFAP)and the cavity area were measured.The cell apoptosis was detected by TUNEL methods at 1,2,3,7 and 14 days after injury.Results:Compared with control group,treated animals gained higher scores after 8 weeks of transplantation.The number and the size of reactive astrocytes,the average volume of cavity,TUNEL positive cells,the expression of Nogo-A and GFAP reduced significantly in group B compared with those of group A(P＜ 0.05).Conclusion:BMSC possess effects on repairing injured spinal cord and promoting functional recovery through various mechanisms.

Objective To observe the clinical outcome of core decompression combined with autologous concentrated bone mar‐row cell transplantation for treatment of early osteonecrosis of femoral head .Methods Forty six patients (82 hips) included in this retrospective analysis were divided into observation group (30 cases ,44 hips) and the control group (26 cases ,38 hips) .The obser‐vation group were treated by autologous BMMSCs transplantation joint core decompression treatment while control group treated only with core decompression .The therapeutic effect of 2 methods of treatment were summarized by comparing the 2 groups after 3 ,6 ,18 months postoperative with Harris hip score and the imaging changes and necrosis area percentage change degree at 18 months postoperatively .Results The Harris scores of the observation group after operation increased significantly [(88 .24 ± 5 .53) score] ,the excellent and good rate was 84 .09% ;the Harris scores of the control group after operation increased significantly [(75 .48 ± 4 .20)% ] ,the excellent and good rate was 71 .05% ;MRI necrosis area of the observation group after operation reduced gradually[(13 .86 ± 4 .27)% ] and the MRI necrosis area of the control group after operation reduced gradually [(19 .53 ± 5 .29)% ] .There was significant difference between them (P<0 .05) .Harris scores and the imaging changes and necrosis area per‐centage change degree of both group had been improved after the operation (P<0 .05) .Conclusion The core decompression com‐bined with autologous concentrated bone marrow cell transplantation for treatment of early osteonecrosis clinical efficacy might be better than core decompression .

Objective To explore the value of improved elasticity scores in differentiating malignant and benign breast lesions. Methods A prospective study was done in 394 patients with 508 breast lesions confirmed by pathology and the elastographic images of the lesions were evaluated by using old and improved elasticity scores respectively. Results The elastographic images of the lesions could be evaluated and classified in all patients by improved elasticity scores but could not be evaluated and classified in 82 lesions by old elasticity scores. The accuracy of ultrasonic elastography for diagnosing benign and malignant breast lesions was 88.8% and 78.1%, respectively by old elasticity scores and improved elasticity scores. Conclusions The elastographic images of breast lesions were accurately evaluated by using improved elasticity scores, and the use of improved elasticity scores is helpful to reduce the biopsy which is not necessary.

Objective To investigate the changing of endothelial progenitor cells and nitric oxide in patients with pulmonary arterial hypertension secondary to chronic obstructive pulmonary disease.Method Mononuclear cells from 20 healthy persons (the control group, n = 20) , COPD patients without PAH (COPD non-PAH group, n =30) and patients with PAH secondary to COPD (COPD and PAH group, n=30) were investigated. Total mononuclear cells were isolated from peripheral blood by Ficoll density gradient centrifugation. EPC number and migration were assayed by colony forming unit-EPCs (CFU-EPCs) assay and modified Boyden chamber assay , respectively. EPC adhesion assay was performed by replanting those on fibronectin-coated dishes , then adherent cells were counted. The concentration of NO was measured with method of nitrate reductase.Result The numbers of CFU and migration, adhesion activity of circulating EPCs in COPD[ (21.9±3. 9)CFU-EPC] and PAH group[ (14. 2 ±3. 5)CFU-EPC] were significantly lower than that in non-COPD group and COPD non-PAH group [ ( 24.9 ±4.1) CFU-EPC ]. It was also observed that a strong negative correlation between the levels of PAH and the numbers of CFU and adhesion, migration activity of circulating EPCs. The NO level in the PAH group [ (43. 6 ±4. 8)ng/ml] was significantly lower than that in control group [ ( 67. 17±4.9 ) ng/ml ] ( P < 0.01). The NO level was positively correlated with number and migration ability of EPCs( r =0. 77,0.71, P <0.01) , but not correlated with adhesion ability.Conclusion The number of CFU and migratory, adhesive activity of EPC in patients withPAH secondary to COPD was significantly decreased. These changes may be associated with low level of plasma NO.

Objective To explore the application of contrast-enhanced scoring system in the diagnosis of breast tumor.Methods 249 patients with 260 lesions were examined by elastography and contrastenhanced ultrasound before surgery.All the lesions were scored according to the two different methods.Pathological results were made the golden criteria.The diagnosis accuracy of the two methods were compared.Results There were 145 benign and 115 malignant tumors.The diagnosis accuracy,specificity and sensibility of elastography were 85.0％,88.3％,80.1 ％ respectively.The critical value of contrastenhanced ultrasound was between 3 and 4.The diagnosis accuracy,specificity and sensibility of contrastenhanced ultrasound were 88.9％,87.6％,90.4％ respectively.Area under ROC curve of the two methods were 0.901 and 0.910,the difference was not statistically significant.Conclusions Contrast-enhanced ultrasound 5-point scoring system was an initial quantitative criterion for breast tumor diagnosis.The diagnosis accuracy was parallel to that of elastography.

Objective To discuss the clinical value of immunofecal occult blood test in screening of colorectal cancer and its precancerous lesions in a large series of health checkup population. Methods Colorectal cancer and its precancerous lesions in 5919 subjects undergoing health checkup in our hospital were screened out by using immunofecal occult blood test from July 2006 to June 2007; positive cases with the test were subjected to colorectal endoscopy or X-ray barium enema examination. Relevant results were analyzed in combination with clinical and pathological data. Results Positive result was obtained in 314 out of the 5919 subjects undergoing health checkup with immunofecal occult blood test; the positive rate was 5.30%. 241 cases(76.75% )of them accepted colorectal endoscopic examination and 23 cases(7.32%) accepted X-ray barium enema examination. The total follow up rate was 84.08% with 50 cases out of contact. After excluding the cases out of cantact, 16 cases of colorectal cancer were found morbidity 2.37‰ including 8(50.00% )cases of Dukes A,7 cases (43.75%)of Dukes B and 1 case of Dukes C (6 .25%).The detection rate of colorectal cancer with postive imunofecal occult blood test was 6.06% (16/264). 94 cases (16.01‰) of adenomatous polyps were found including 55 cases (58.51%) of tubular adenoma, 23 cases (24.47% )of villiform- tubular adenoma and 16 cases(17.02%) of villfform adenoma. Among these cases 55 (58.51%)were solitary and 39(41.49%) multiple. In addition, 6 cases of ulcerative colitis in active phase were found. Altogether 116 (43.94%)of the 264 cases with positive immunofecal blood test and not out of contact were found to have colorectal cancer or its precancerous lesions. Conclusion Immunofecal occult blood test is suitable for screening of colorectal cancer and its precancerous lesions in large series of population. Colorectal cancer and its precancerous lesions may be found in relatively early phase and be eradicated in curable stage, thus to reduce the morbidity and mortality.