BACKGROUND:The creep characteristics of cancellous bone from necrotic femoral head are important for clinical artificial joint replacement.Therefore,it is necessary to study mechanical properties of cancellous bone at 45°direction.OBJECTIVE:To compare creep properties of normal femoral head and necrotic femoral head at 45°direction based on three-parameter model established creep equation METHODS:A total Of 8 normal and 8 necrotic femoral heads were used.The cancellous bone was harvested at 45° and subjected to creep test on electronic universal testing machine.With simulated temperature field of human body temperature at36.5℃.stress was imposed on the samples by an increase of 5%/s for 7 200 seconds.100 experimental data were collected,and stress relaxation equation was calculated using three-parameter model.RESULTS AND CONCLUSION:The creep curve of the femoral head of normal and necrotic changes was exponential relation.Changes were fast in the first 600 seconds,and strain increased slowly with time,finally entered into balance stage.7 200 s creep of cancellous,bone from necrotic femoral head was less than normal femoral head cancellous bone.Three-parameter model calculation is simple and can well fit the creep of changes in the femoral head.The establishment of such idealized equation quantitatively shows poor visco-elasticity of the necrotic femoral head.

Objective: To assess the peculiarity in fluorine-18 fluorodeoxyglucose (FDG) uptake in patients with bronchial alveolar carcinoma. Methods: From December, 1998 to April, 2002, 22 patients with bronchial alveolar carcinoma (BAC) were imaged with FDG-PET (positron emission tomography) before surgery. Their maximum and mean standard uptake value (SUVmax and SUVmean ) of tumor and SUV of normal lung (SUVlung) were measured. Results: All tumors were detected by FDG-PET. FDG uptake of tumor was higher than that of normal lung (P

Objective To analyze the imaging manifestations of chondromyxoid fibroma,so as to improve diagnostic accuracy.Methods The X-ray,CT and MRI manifestations of 8 cases with chondromyxoid fibroma confirmed by surgical pathology were analyzed retrospectively.Results All of 8 cases were in the long tubular bones.X-ray showed oval,well defined,eccentric,radiolucent lesion with surrounding sclerosis.The thick dense bony or coarse reticular septation were seen in 6 cases.CT scan showed osteolytic,surrounding sclerosis,and 1 case with foci of calcification.MRI images showed a low or medium signal on T1WI,high signal on T2WI,1 case with a equal T1WI and slight high T2WI signal intensity peripheral rim around.Two cases with diffused enhancement on T1WI after intravenous injection of gapentetate acid meglumine injection and a peripheral liner enhancement in 1 case.Conclusion Chondromyxoid fibroma has certain imaging characteristics,but should be combined with X-ray,CT and MRI to differentiate from other bone tumors with similar imaging manifestations.

Objective To investigate the effect of remote ischemic postconditioning on brain injury after asphyxial cardiac arrest-resuscitation in rats.Methods Sixty-nine male Sprague-Dawley rats were randomly divided into 3 groups (n =23 each) using a random number table:sham operation group (group S),asphyxial cardiac arrest-resuscitation group (group CA-CPR),and remote ischemic postconditioning group (group RIPost).The animals were anesthetized with intraperitoneal 1％ pentobarbital 40 mg/kg,intubated and mechanically ventilated.Asphyxia was induced by occlusion of the tracheal tube and resuscitation was started 8 min later.In RIPost group,RIPost was produced by 3 cycles of 15 min occlusion of the right hind femoral artery-15 min release of the right hind femoral artery after restoration of spontaneous circulation (ROSC).Neurological deficits were evaluated and scored at 24 h,72 h and 7 days after ROSC.Neuron specific enolase (NSE) concentration in serum was assessed at 48 h after ROSC by ELISA.At 3 days after ROSC,the number of viable neurons in hippocampal CA1 region was recorded (by N issl's staining).Morris water maze test was used to quantify spatial learning and memory deficits after ROSC.Results Compared with group S,the neurological deficit score at each time point and the number of viable neurons in hippocampal CA1 region were significantly decreased,the NSE concentration in serum was increased,the escape lantency was prolonged,and the target quadrant residence time percentage and distance percentage were decreased in CA-CPR and RIPost groups.Compared with group CA-CPR,the neurological deficit score at each time point and the number of viable neurons in hippocampal CA1 region were significantly increased,the NSE concentration in serum was decreased,the escape lantency was shortoned,and the target quadrant residence time percentage and distance percentage were increased in group RIPost.The damage to neurons in hippocampal CA1 region was significantly mitigated in group RIPost as compared with group CA-CPR.Conclusion Remote ischemic postconditioning can reduce brain injury after asphyxial cardiac arrest-resuscitation in rats.

Objective To provide a device and an effective method for tail vein injection in mice. Methods Doing the tail vein injection in mice with the self-designed device which is consisted of constant temperature part, lighting part and holding part.The difficulty and time of injection with and without the device were compared.Results It was faster and more accurate to perform the tail vein injection in mice with this self-designed device.Conclusion Using this self-designed device can significantly improve the efficiency and save the injection time.

Objective:To investigate the differences in related indices of ulcerative colitis (UC) respectively induced by free drinking and intragastric administration of dextran sodium sulfate (DSS) in mice to provide experimental reference for the optimization of UC model.Methods:Totally 30 C57BL/6 mice were randomly divided into the normal control group,free drinking group and intragastric administration group with 10 ones in each.The mice drank water freely with free drinking or intragastric administration of 3% DSS solution at the dose of 4 g·kg-1·day-1 for 7 days to establish the UC model.The differences in disease activity index (DAI),histological damage sore and activity of myeloperoxidase (MPO) among the groups were compared.Results:Two mice died during the experiment in the free drinking group,and DAI of survival mice was (8.8±1.6).There was no death of mice in intragastric administration group,and DAI was (9.0±0.8),and there was no significant difference in DAI between the groups (P>0.05),while the coefficient of variation in the free drinking group was higher than that in the intragastric administration group (18.7 vs 8.6).The colonic histological damage score of the free drinking group and the intragastric administration group was 24.8±4.2 and 27.0±2.8,respectively,which was typical inflammatory change with no significant difference (P>0.05),while the coefficient of variation of the free drinking group was higher than that of the intragastric administration group (16.9 vs 10.4).MPO of the normal control group,free drinking group and intragastric administration group was (0.41±0.03),(2.32±0.34) and (2.05±0.18) U·g-1,respectively.Compared with the normal control group,significant difference in MPO was shown in the free drinking group and the intragastric administration group (P<0.01),while there was no significant difference in MPO between the groups (P>0.05),and the coefficient of variation in the free drinking group was higher than that in the intragastric administration group (14.7 vs 8.8).Conclusion:Both free drinking and intragastric administration of DSS can successfully induce the UC model in mice.Compared with the free drinking group,the intragastric administration group has low mortality rate and low coefficient of variation.Therefore,intragastric administration has more advantages than free drinking in inducing the UC model in mice.

AIM:To investigate the effects of brain-derived neurotrophic factor(BDNF)on extracellular proteolytic enzymes including matrix metalloproteinases(MMPs)and serine proteases,in particular,the urokinase-type plasminogen activator(uPA)-plasmin system in a human umbilical vein endothelial cell(HUVEC)model.METHODS:The HUVEC was activated with different doses of BDNF(25-200 ?g/L)for different time period(6-48 h).Reverse transcriptase-polymerase chain reaction(RT-PCR)was used to assay MMP-2,MMP-9,TIMP-1,and TIMP-2 mRNA in HUVEC.The cultured conditioned medium was analyzed for MMP and uPA activity by gelatin zymography and fibrin zymography,respectively.uPA,PAI-1,TIMP-1,and TIMP-2 were quantified by Western blotting analysis.RESULTS:The stimulation of serum-starved HUVECs with BDNF caused marked increase in MMP-2 and MMP-9 mRNA expression and induced the pro-MMP-2 and pro-MMP-9 activation without significant differences in proliferation.However,BDNF had no effect on TIMP-1 and TIMP-2 production.BDNF increased uPA and PAI-1 production in a dose dependent manner up to 100 ?g/L,while effects of 200 ?g/L were approximately equal to those of 100 ?g/L.BDNF stimulated uPA and PAI-1 production beyond that in control cultures from 12 h until 48 h after BDNF addition.Protease activity for uPA was also increased by BDNF in a dose dependent manner.CONCLUSION:BDNF activates MMP and uPA/PAI-1 proteolytic network in HUVEC.

Objective To summarize our experience in the diagnosis and management of popliteal artery entrapment syndrome (PAES). Methods This is a retrospective study on 10 patients (13 limbs)who were admitted for symptoms of claudication and the diagnosis of popliteal entrapment was established either with angiography,computed tomographic angiography,magnetic resonance angiogram or during the operation in recent 7 years (2002-2009).All patients were treated surgically. Results The mean age at the time of presentation was (25 ±7) years old (range,17-41 years).Claudication was the most frequent presenting symptom (12 limbs).The surgical procedures consisted of simple musculotendinous dissociation in 1 limb,thrombectomy with balloon angioplasty in 1 limb,musculotendinous dissociation plus thromboendarterectomy with autogenous saphenous vein (ASV)patch angioplasty in 2 limbs,ASV graft interposition or bypass in 6 limbs and graft interposition or bypass in 3 limbs.At a median follow-up of (35 ±27) months (range,2 months-7 years),there were no intraoperative or long-term postoperative complications and all the patients were cured. Conclusions PAES is an unusual but important cause of peripheral vascular insufficiency especially in young patients.A combined approach is necessary for diagnosis.Popliteal artery release alone or with vein bypass or reconstruction is the treatment of choice.

According to the investigation about the current ability of military hospitals to cope with bioterrorism , we suggest that military hospitals improve the capability for bioterrorism response based on the research above by satisfying mission requirements , combining peacetime with wartime , carrying out crisis management , classifying response and cooperating with local sectors .

Objective To investigate the effect of natural killer (NK) cells treated by serum of severe preeclampsia patient on the function of endothelial cells.Methods Fifteen patients with severe preeclampsia and 15 normal pregnant women from the Obstetrics department,Shengjing Hospital,China Medical University were admitted into this case-control study from January 1,2006 to December 31,2008.NK cells from healthy non-pregnant woman were incubated with 20% serum from severe preeclampsia patients or normal pregnant women for 20 hours.Then,human umbilical vein endothelial cells ( HUVEC) and serum-treated NK cells were co-incubated for 24 hours.Apoptosis of HUVEC was checked by flow cytometry and electronic microscope.Endothelin-1 (ET-1) levels in the supernatants of HUVEC and NK cells were examined by radioimmunologic method.Results In severe preeclampsia group,the percentage of early apoptosis cell (Annexin V-FITC+ /PI+ ) was (23.81±4.79)%,that of late apoptosis cell (AnnexinV-FITC+/PI+ ) was (3.29±1.04) %,while those were (16.59±5.13)% and (2.24±0.72)% respectively in normal pregnant group (P＜0.01).There was no significant difference in dead cells (Annexin V-FITC- /PI+ ).Under electronic microscope,typical morphologic changes of apoptosis were shown in severe preeclampsia group.Level of ET-1 in