Objective: To deeply investigate the influential factors of mental health in medical students by structural equation modeling.Methods: 480 medical students were tested with SCL-90,adolescent self-rating life events check list and simplified coping style questionnaire,then theoretical model were established and confirmed for the relationships of life events,satisfaction degree with their profession,coping styles and mental health.Results: Study stress,human relations,satisfaction degree towards their profession and coping styles closely correlated with mental health status,and the structural equation modeling fitted the data very well,GFI and AGFI were both larger than 0.90.Conclusion: Use of structural equation modeling has more advantages than the traditional statistical methods,but it should combine with professional knowledge when it is used.

BACKGROUND: Ischemia/reperfusion can induce degenerative alterations in articular cartilage. However, the precise mechanism remains poorly understood. OBJECTIVE: To observe the morphological changes and the apoptosis of articular cartilage of femoral head epiphyses with ischemia/reperfusion. METHODS: A total of 80 Sprague-Dawley rats were randomly assigned to two groups: ischemia/reperfusion (model of ischemia/reperfusion in hip joint) and sham-surgery (exposure of abdominal aorta for 5 minutes) groups, with 40 animals in each group. Articular cartilages of femoral head epiphysis were col ected in 6, 12, 24, and 48 hours, 5 days, and 2 and 4 weeks after operation. Morphology of articular cartilage of femoral head epiphyses was examined by light microscope, and cel apoptosis was detected by TUNEL method. RESULTS AND CONCLUSION: Light microscopy showed chondrocytes degeneration and reduction, as wel as fibrosis in matrix of cartilage in the ischemia/reperfusion group. Chondrocyte apoptosis was observed in both groups by TUNEL. Several apoptotic cells, less than five, were observed in the sham-surgery, while 10-30 apoptotic cells were found in ischemia/reperfusion group at 48 hours. Results indicated that ischemia/reperfusion can induce degenerative changes in articular cartilage of femoral head epiphyses, and cel apoptosis in developing hip joint may participate in damage of articular cartilage. Inhibition of chondrocyte apoptosis in articular cartilage may be useful for the prevention and cure of early osteoarthritis.

AIM: To investigate the effects of dehydroepiandrosterone (DHEA) on experimental osteoarthritis in rats. METHODS: Forty rats were randomly divided into four groups. Group A is normal control group. Osteoarthritic models of rats were established by intraarticular injections of papain into the right knee joints of groups B, C and D. Then the right knee joints of rats in groups C and D, respectively, received 150 ?l intraarticular injections of DHEA at a concentration of 50 ?mol?L~(-1) and 100 ?mol?L~(-1), and the right knee joints of rats in groups A and B both received 150 ?l physiological saline, twice weekly for five weeks. Six weeks later, all rats were sacrificed, and the articular cartilage was assessed by gross morphologic, histologic, biochemical and immunohistochemical methods. RESULTS: The cartilage damage in groups C and D was much less than that in group B through observation under a surgical microscope. The Mankin's score, nitric oxide (NO) in the douche of articular cavity, malondialdehyde (MDA) in synovium, the expression of matrix metalloproteinase-1 and 9 in articular cartilage in groups C and D decreased in comparison with group B, and the foregoing indexes in group D decreased significantly compared with group C. However, the activities of superoxide dismutase (SOD) in the douche of articular cavity and blood serum in groups C and D increased in comparison with group B, and the foregoing indexes in group D increased significantly compared with group C. CONCLUSIONS:DHEA shows a cartilage-protecting effect which is in a dosage-dependent manner. The mechanism probably is to inhibit the expression of matrix metalloproteinases and to decrease the release of (NO and enhance the antioxidation.

Obiective To compare the sensitivity and specificity of strain imaging(SI)and restredistribution Tl-201(RR-201 TI)SPECT imaging in evaluating myocardial viability among patients with STelevation acute myocardial infarction(AMI).Methods Twenty-six AMI patients underwent echocardiography and RR-201 Tl-SPECT imaging a week(baseline)after percutaneous coronary intervention(PCI)therapy.At baseline,wall motion score(WMS)and systolic strain were assessed,SPECT scoring were performed on 16 segments of left ventricle(LV).WMS was repeated more than 3 months later to assess myocardial viability,which is deemed as reference.Results ①Two hundred and sixty segments in the"at risk"regions were followed up for(5±2)months,among which 201 were identified as viable and 59 were not,according to the WMS.②In comparison to the reference standard,the sensitivity and specificity of RR-201 Tl-SPECT to predict myocardial viability were 87%(175/201)and 58%(34/59)respectively.③The sensitivity and specificity of systolic strain(Set)to predict myocardial viability after AMl were 81% and 66% respectively at the optimal cut-off value of-60%.④Set was moderately concordant with SPECT scoring(Kappa=0.40)and the agreement between the two methods was 77%(199/260).Conclusions In ST-elevation AMI,SI and RR-201 Tl-SPECT appears equivalent in predicting segmental recovery after reperfusion,and SI could be a convenient and low-cost alternative for the non-invasive evaluation of myocardial viability.

Objective To study the biomechanical mechanism of Essex-Lopresti injury, and provide biomechanical basis for diagnosis and treatment of Essex-Lopresti injury. Methods Twelve fresh frozen adult upper limbs were addressed. Firstly, 12 samples ("complete state group") were loaded 100 N of a compressive force lasting 30 seconds in pronation, supination and neutral position on the mechanical testing machine. Secondly, 12 specimens were randomly divided into 2 groups. In the group named resection of radial head, the radial head was removed and interosseous membrane (IOM)was intact. In the group named the section of interosseous membrane, IOM was cut off. Finally, the radial head were removed and IOM was cut off in all specimens. The group was named as resection of radial head and IOM. Each sample was tested according to the method as described. Results The forearm rotation or single excision of the IOM had no effect on radial longitudinal displacement. Simple radial head excision or resection of the IOM and the radial head increased the vertical displacement of the radius. The radial stiffness had a gradual decline in forearm supination, neutral position and pronation. Simple excision IOM has no effect on the radial stiffness. The radial stiffness had decreased under the condition of excision of radial head or resection of the IOM and the radial head. Conclusion These in vitro measurements validate that the radial head fracture with IOM injury may be important reason for complications of the Essex-Lopresti injury. Radial head fracture play a key role for Essex-Lopresti injury and the injury of IOM is secondary cause. IOM is responsible for maintaining the vertical stability of the forearm after radial head resection.