BACKGROUND: Biomechanics of bone in vivo is concerned by the scholars who work for orthopaedic and medical bioengineering all the time. The application of strainmeter in this measurement has been studied for many years, but the long-term and successive measuring problems have not been solved. A new installing method for analyzing biomechanics of bone in vivoshould be considered to be explored. OBJECTIVE: To investigate the biochemical change of external fixator at both external and internal medullary cavity of anxial compressing fracture end invivo when external fixator is used DESIGN: Randomized and controlled animal experiment SETTING: Laboratory of Orthopaedic Department, Renmin Hospital, Wuhan University MATERIALS: Totally 18 healthy white rabbits, of rather gender, with the body mass of 3.6 to 4.2 kg , were chosen. METHODS: This experiment was conducted at the laboratory of Or thopaedic Department, Renmin Hospital, Wuhan University in November 2004. The chosen 18 healthy white rabbits were randomly divided into 2groups. External measuring group (Group A): the strain guage was affixed to the tibia external cortex by 502 gauge. Internal measuring group (Group B): strain guage coated with bone cement was installed on the tibia internal cortex. Group A and Group B were divided into two subgroups A1, A2 and B1, B2, respectively according to the pressure 0.5 time body mass and 1 time body mass. Strain voltage change and attenuation coefficient after compressing were measured with scaler. Statistical comparison was performed among the groups. MAIN OUTCOME MEASURES: ① The data of scaler curve. ② Attenuation coefficient of different compressions.RESULTS: ① The scaler curves of Group A changed greatly during early stage. After reaching stable stage, trendline of internal and external cortex went consistent but the former value was higher than that of the latter . The time of compression reaching stable was shorter in the Group B than in the Group A, and the absolute value of strain was smaller in the Group B than in the Group A. ② Before reaching stable after compression, the attenuation coefficient was low in the Group A1 as compared with Group A2. There was the same result between Group B1 and Group B2 group. When comparison was conducted between Group A and Group B, the curve of Group A decreased firstly, then ascended, but there was no ascending tendency in the Group B. After reaching stable, there were descending tendency in the Group A1 group and Group A2. It descended fast in the Group A2, while it kept at normal level in the Group B1 group. Fluctuation appeared in the Group A2. CONCLUSION: Strain of external medullary cavity is significantly larger than that of internal medullary cavity. It is easier to reach stable in the inter nal medullary cavity than in the external medullary cavity. 0.5 time of body mass is suitable at the initial period in treating fracture with external fixator.

Objective To compare the infection free and overall survival between first and subsequent tunneled cuffed hemodialysis catheters in geriatric patients.Methods The study involved57 geriatric patients [32 male,25 female; mean age (72.4 ± 6.7) years]undergoing maintenance hemodialysis in our blood purfication unit over a period of 72 months.Among a total of 131 catheters and 2686 catheter months including 57 first catheters and 74 consecutive catheters,48 wire guided exchange (WGE) and 26 removal and replacement (RAR),55/131 (42.0％) catheters were exchanged because of catheter-related bacteremia (CRB),37131 (28.2％) exchanged because of malfunction or cuff extrusion,39 /131 (29.9％)catheters were removed electively or was still functional at the end of the study period.Results One-year survival rates for first and consecutive catheters were 35.8％ and 28.4％,respectively.There was no difference in the overall survival between first catheters group and subsequent catheters group [(29.8±7.9)months vs.(28.7±6.0)months,t=0.711,P=0.443].However,infection free survival of first catheters group was significantly prolonged in comparison with that of subsequent catheters group [(13.1 ± 3.5) months vs.(11.6±2.7) months,t =2.415,P=0.018].The overall and infection-free survival in WGE group were not different with those of RAR group [(28.2 ± 7.2 ) months vs.( 28.5 ± 5.8 ) months,(11.1±3.1)months vs.(12.2±2.1)months,t=-0.163,0.103,P＞0.05].The infection free survival of first catheters group and WGE group was prolonged in comparison with that of in situ group[(13.1±3.5)months and (11.1±3.1)months vs.(8.2±2.1)months,t =7.602,5.601,P＜0.05].Conclusions WGE is safe and effective in the elderly patients if the tunnel and the exit site are not infected and has the potential benefit of preserving the vascular access site.

Abdominal aortic aneurysms(AAAs) is the most common aneurysm,and usually characterized by less symptom.While ruptured AAAs leads to high mortality.Abdominal ultrasonography can effectively detect AAA,decrease the AAAs-related mortality.However,screening AAAs causes some adverse outcomes,including psychological distress and immediate harms in treatment.Meanwhile,the prevalence of AAAs in sex and age is significantly different.Therefore,a reasonable and effective screening strategy is very important.This article search random control trials,systematic reviews,meta-analysis and guidelines in screening AAAs to obtain a reasonable screening strategy.

Objective To compare the therapeutic results of laparoscopic and open treatment for choledocholithiasis. Methods A prospective comparison was conducted between 29 cases of laparoscopic choledocholithotomy and 35 cases of open choledocholithotomy in terms of stone removal,operative time,hospitalization day,hospitalization cost and postoperative complications. Results Stone removal was achieved in 28/29 patients by a laparoscopic approach and in 32/35 patients by a open approach( ? 2=0 71, P =0 399);average operative time was (178 3?32 4) min in laparoscopic approach and (145 8?27 1)min in open approach( t =4 27, P =0 01);the patients in laparoscopic procedures had flatus in (20 8?2 9) hour and those in open procedures did in (58 2?4 9) hours( t =37 8, P 0 05);no major complication was found in laparoscopic approach. Conclusions Laparoscopic choledocholithotomy is safe and effective and it is superier to open treatment.

BACKGROUND: Many scholars adopt allograft interbody fusion for vertebral body resection and reconstruction, bone fusion time is better than autologous bone graft's, and its integration provides an early support and stabilizing, but the preparation of allogeneic bone graft material is easy to destroy b0ne-inducing factor in matrix, which is not conducive to bone growth. OBJECTIVE: To innovatively design and verify the ability of reconstructing rabbit cervical vertebrae with the compound of humeral cortical ring allograft (HCA) packed with red bone marrow (RBM) and autogenous cancellous bone (ACB). DESIGN, TIME AND SETTING: Randomized controlled animal experiment was performed at the laboratory of Orthopedic Department in Renmin Hospital of Wuhan University, between October 2004 and March 2006. MATERIALS: Sixty healthy adult New Zealand white rabbits, of either sex, body mass of 2.0-2.5 kg, were involved in this study. Twelve rabbits were used for HCA preparation, while the remaining 48 rabbits were randomly divided into 3 groups with sixteen rats in each group. Autologous RBM was extracted from the anterior superior lilac spine through puncture; ACB was obtained from td-cortical bone of rabbit iliac crest. Autologous RBM and ACB were compounded and filled in the self-made HCA. METHODS: Models of the fourth cervical vertebrae defect were created by surgery to simulate tumor resection in New Zealand white rabbits, which were divided into 3 groups randomly. Combined transplant group was treated with the compound of RBM+ACB+HCA; autologous bone transplant group with autogenous lilac crest; HCA transplant group with HCA. MAIN OUTCOME MEASURES: Vertebral reconstructions were evaluated by X-ray, histopathological observation and scanning electron microscope, as well as measurement of serum alkaline phosphates at different periods postoperatively. RESULTS: Eight weeks post-surgery, graft materials fused with the upper and lower cervical fusion, a large number of bone callus were observed in combined transplant group and autologous bone transplant group; HCA transplant group was present with a small amount of callus growth and poor fusion. Serum alkaline phosphatase levels were elevated in all groups, significantly higher in combined transplant group and autologous bone transplant group compared with HCA transplant group (P < 0.01 ). There were no significant differences of serum alkaline phosphatase levels between combined transplant group and autologous bone transplant group at 4 weeks or among 3 groups 8 weeks (P > 0.05). Histological analysis exhibited numerous mature bone matrix, bone trabecula and bone marrow cavity formed in combined transplant group and autologous bone transplant group. Scanning electron microscopy showed that many new bone formations in combined transplant group and autologous bone transplant group.CONCLUSION: The compound of RBM+ACB+HCA and autogenous lilac crest transplantation can efficiently reconstruct cervical vertebrae, RBM+ACB can improve the reconstruction efficiency of HCA, and could use as a matedal in cervical reconstruction.

BACKGROUND: Vertebral reconstruction is stil a chal enge for spinal surgeons. Ideal reconstruction materials should have good osteogenesis ability, reliable support performance, low price and simple operating steps.
OBJECTIVE:To investigate the effect and feasibility of al ogenic cortical ring packed with autogenous cancellous bone in the reconstruction of rabbit cervical vertebra defect.
METHODS:Cervical vertebra defect models were established by resection of the fourth cervical vertebra in rabbits. Frozen-dried humeral cortical ring of rabbits was made to prepare the al ogenic cortical ring which was packed with autogenous cancellous bone. Then, al ogenic cortical ring packed with autogenous cancellous bone, single al ogenic cortical ring and autogenous iliac bone were used to repair rabbit cervical vertebra defects.
RESULTS AND CONCLUSION:The X-ray, histopathological examination, and scanning electron microscope examinations al showed that the bone union was most significant in group reconstructed with al ogenic cortical ring packed with autogenous cancellous bone. The alkaline phosphates activity in serum was higher in groups reconstructed with al ogenic cortical ring packed with autogenous cancellous bone and with autogenous iliac bone than in group reconstructed with only al ogenic cortical ring at 2 and 4 weeks after operation (P<0.01), but there was no difference between the former two groups. The biomechanical examination showed that the stability of al ogenic cortical ring packed with autogenous cancellous bone was higher than that of autogenous iliac bone at 1 month after operation (P<0.01). These findings indicate that the effect of al ogenic cortical ring packed with autogenous cancellous bone in the reconstruction of rabbit cervical vertebra defects is satisfactory, with a good biocompatibility, which is a promising method for the reconstruction of vertebral defects.

Objective To explore the value of E-Tracking technique in evaluating the vascular endothelial function of carotid artery in subclinical hypothyroidism.Methods The study population include 38 subclinical hypothyroidism patients and 60 normal controls.E-Tracking technique was performed to track the movements of the common carotid artery and the following parameters were assessed:stiffness parameter(β),elastic coefficient (Ep),arterial compliance (AC),augment index (AI) and one point pulse wave velocity (PWVβ).Results Ep,β,AI and PWVβ were significantly higher in subclinical hypothyroidism than those in the control group,AC were lower than that in the control group( P ＜0.05).Conclusions Vascular endothelial function in subclinical hypothyroidism patients is injured in early stage.ETracking technique may conduce to find the injury early and may assess it quantitatively.

Uninephrectomy was performed in a ll rats of this study, and diabetic model was induced in partial rats by streptozo tocin. Then these rats were divided into uninephrectomy group, diabetes group an d benazepril-treated diabetes group. After 4 weeks, renal tubulo-interstitial morphological change was observed and type Ⅳ collagen, fibronectin and transfor ming growth factor ? 1 (TGF-? 1) proteins as well as TGF-? 1 mRNA were d etermined. The results suggested that benazepril played a protective role in ren al tubulo-interstitial injury, which was associated partially with down-regula ted overexpression of TGF-? 1.

Objective To observe the protective effect of sodium hyaluronate (Na-HA),and its effects on mRNA expression of peroxisome proliferators-activated receptor gamma (PPAR-γ) in cartilage of rabbit osteoarthritis (OA) model.Methods Forty eight white rabbits were divided into A,B,C groups randomly.Group A were normal controls,groups B and C were underwent unilateral anterior cruciate ligament transection (ACLT).The rabbits in group B were injected normal saline after ACLT;Group C rabbits received intra-articular 1% sodium hyaluronate (HA) injections 5 weeks after surgery,0.3 ml once a week.At week 11 after the surgery,all rabbits were sacrificed.The cartilage changes on the medial femoral condyles were graded.Cartilage sections were stained with safranin-O and HE,mRNA expression of PPAR-γ was detected by real time polymerase chain reaction (Real Time-PCR).Results Cartilage degeneration in group B was significantly more severe than in groups A and C.The grey value of Safranin-O of B group were higher than groups A and C.Expression of PPAR-γ mRNA in group B was higher than that in groups A and C.Conclusion NaHA has a protective effect on articular cartilage degeneration,and the inhibitory effect on PPAR-γ mRNA expression may be one of the therapeutic mechanism of Na-HA.

AIM: To observe the effect of diammonii glycyrrhizinatis (DG) on collagen synthesis induced by angioplasty in rabbits. METHODS: The right common carotid artery of male rabbits were injured with 3.5F balloon catheter. Four weeks after operation, arterial tissure collagen content, serum procollagen type I(PCI), procollagen type Ⅲ(PCⅢ) concentration, neointimal thickness and the rate of stenosis were measured.RESULTS: Arterial tissue collagen content, serum PCI, PCⅢ concentration, neointimal thickness and the rate of stenosis of low and high dose DG group is lower than those of injured group.CONCLUSION: DG could inhibit collagen synthesis and neointimal proliferation of rabbits carotid artery induced by angioplasty. It suggests that DG might have clinical potential prespective in prevention and therapy of restenosis.