Objective To explore the spatial distribution of microstructural parameters and mechanical properties for trabecular bone in the femoral head with osteonecrosis. Methods Microstructural parameters and mechanical properties of trabecular bone in different regions were analyzed by combined use of imaging measurements and numerical simulation method, and the spatial distribution of biomechanical properties for trabecular bone along coronal, sagittal and vertical directions was investigated. Results Microstructural characteristics and mechanical properties of trabecular bone were Y-shaped distributed along coronal and sagittal directions, and mechanical properties of trabecular bone in Y-shaped region were higher than those in the other regions. Such distribution characteristics was consistent with the location of principle compressive group in the femoral head. Conclusions Necrotic lesions in Y-shaped region had a greater influence on stress distribution of the femoral head and might cause the deterioration of osteonecrosis. The spacial correlation between necrotic lesions and Y-shaped region should be fully considered during clinical diagnosis.

Objective To measure mechanical properties of calcified tissues from human aortic valve by nanoindentation test. Methods Leaflets from 5 patients with aortic stenosis were collected. Elastic modulus and hardness of the calcified leaflets were obtained by nanoindentationtest. Results The elastic modulus and hardness of the calcified leaflets were (15.69±3.89) GPa and (0.59±0.15) GPa, respectively. Conclusions The elastic modulus and hardness of the calcified valve tissues can be obtained by nanoindentationtest, which provides experimental data for biomechanical research of the valve.

Objective:To investigate the effect of O-arm navigation assisted posterior pedicle screw reduction and internal fixation of atlantoaxial fractures.Methods:A retrospective case-control study was conducted to analyze 37 patients with atlantoaxial fractures admitted to Third Hospital of Hebei Medical University from January 2016 to June 2018, including 22 males and 15 females, aged from 29 to 68 years [(50.9±9.8)years]. The posterior pedicle screw reduction and internal fixation was performed under O-arm navigation system (navigation group, n=24), and using free-hand technique (free-hand group, n=13). The operation time and blood loss were compared between the two groups. The Japanese Orthopaedic Association (JOA) score and neck disability index (NDI) were used to evaluate the clinical efficacy before operation, 7 days operation and at the last follow-up. The complications were detected. A total of 86 screws were placed in navigation group (Neo grade 0: 83 screws, grade 1: 2 screws, grade 2: 1 screw ), and 44 screws were inserted in free-hand group (Neo grade 0: 36 screws, grade 1: 5 screws, grade 2: 2 screws, grade 3: 1 screw)( P<0.05). Classification of screw positions proposed by Neo et al was used to evaluate the position relationship between the screw and the bone cortex and the incidence of screw penetration. Results:All patients were followed up 24-38 months [(27.7±4.0)months]. The operation time in navigation group was (189.8±35.4)minutes, significantly shorter than (221.5±48.6)minutes in free-hand group ( P<0.05). The bleeding volume in navigation group was 300.0 (250.0, 537.5)ml , significantly less than 500.0 (425.0, 625.0)ml in free-hand group ( P<0.05). Both groups showed significantly enhanced JOA and decreased NDI after operation and at last follow-up, compared with those before operation ( P<0.05). However, there was no significant difference in JOA and NDI between the two groups ( P>0.05). No severe complications such as neurovascular injury occurred during operation. The incidence of cortical penetration was 3% (3/86) in navigation group and 18% (8/44) in free-hand group ( P<0.05). Conclusions:In the process of posterior atlantoaxial pedicle screw placement, the application of O-arm navigation can significantly reduce the operation time and amount of bleeding, and enhance the accuracy of pedicle screw implantation.

Oblique lateral interbody fusion (OLIF) was minimally invasiveprocedure for lumbar interbody fusion (LIF) through the space between anterior margin of retroperitoneal psoas major muscle and the vessels (ATP). Although OLIF had many advantages over other approaches, there were also various kinds of surgical complications, the incidence of which was 3.69%-81.82%. Most of the complications were relieved by conservative or symptomatic treatment. Only a small number of complications were difficult to recover, if so, revision surgery was needed and might remain persistent symptoms. OLIF complications included intraoperative and postoperative complications. Major vascular injury was a dangerous complication during operation, which requires immediate compression or suture to prevent bleeding. The incidence of nerve injury could be reduced by avoiding violent traction and tissue separation and reducing the operation time. When injury of thorax and peritoneum occurs, suture should be done as soon as possible. Transient hip flexion weakness and transient thigh/groin sensory disturbance was the most common post-operative complication, most of which would disappear after several months. Intestinal obstruction is caused by the pulling of peritoneum during operation, most of which was incomplete and would be relieved after some time. Postoperative infection was mostly superficial and would be cured by dressing change and antibiotic application. Subsidence of cage and collapse of intervertebral space were the most common complications related to instrumentations which might not lead to related clinical symptoms; however the severe cases need to be repaired. The incidence of pseudarthrosis is relatively low and a few patients with clinical symptoms need revision surgery. The sample size of most studies was small and follow-up period was short. In the future, large samples and multi-center studies are needed to improve our understanding of OLIF complications in the future.

Objective: To analyze the genetic characteristics of norovirus(NoV) in Jilin province from 2014 to 2016. Methods: Stool samples from children under 5 years of age with diarrhea were collected from Changchun Children′s Hospital. Samples were amplified by RT-PCR. The polymerase and capsid gene of the positive specimens were amplified.Sequences were analyzed by homologous comparison and phylogenetic analysis. Results: A total of 1 335 samples were detected, 177 were positive for NoV, and positive rate was 13.26%. The positive rate was 11.83% in 2014, 12.53% in 2015 and 15.75% in 2016. Genotyping of polymerase region revealed GII.P12 types dominated in 2014 and GII.Pe types dominated in 2015 and 2016. Genotyping of polymerase region revealed that GII.3 types dominated in 2014 and GII.4_Sydney2012 types dominated in 2015 and 2016. The types of both regions included GII.P17/GII.17, GII.Pe/GII.4_Sydney2012, GII.P12/GII.3, GII.Pe/GII.3、GII.P16/GII.2 and GII.P7/GII.6. Conclusions Genotypes of NoV infection are diverse in Jilin province. Most of them are recombinant strains. The main epidemic strains changed from GII.P12/GII.3 in 2014 to GII.Pe/GII.4_Sydney2012 in 2015 and 2016.

OBJECTIVETo detect mutations of the XPC (XPC complex subunit, DNA damage recognition and repair factor) gene in a family affected with xeroderma pigmentosum group C (XP-C).

METHODSThe patient was subjected to next-generation sequencing and Sanger sequencing. Suspected mutations were validated by Sanger sequencing. Effect of splicing mutation was confirmed by reverse transcription-PCR (RT-PCR).

RESULTSCompound heterozygous mutations of c.2098G to T and c.2034-7_2040del were found in the XPC gene in the proband. Among these, c.2098G to T (p.G700X) is a nonsense mutation resulting in a truncated XPC protein. C.2034-7_2040del involves the -1 position, which may alter the splice donor site of the intron 11 of XPC and result in a truncated XPC protein with loss of amino acids from 940 to 679 positions. The two mutations were not detected among 100 unrelated healthy controls.

CONCLUSIONMutations of c.2098 G to T and c.2034-7_2040del of the XPC gene may lead to abnormal XPC expression and reduction or elimination of normal XPC functions, which may underlie the disease in this family.

Objective To develop an albumin aptamer that may potentially serve as a selective ligand for albumin removal from experimental samples.Methods A single-stranded 59nt DNA library that contains 21 random oligo nucleotides was synthesized in vitro.An albumin aptamer A6 was developed by SELEX technique using bovine serum albumin (BSA) as target.The enrichment of aptamer and evaluation of its binding properties were monitored by flow cytometry.The secondary structure of A6 was predicted by MFord software.Results The aptamer A6 strongly bound to BSA with a Kd of 77.4 nmol/L,and had minimal cross reactivity with control proteins including ovalbu min,IgG,and trypsin.Conclusions Aptamer A6 may be a potential tool in albumin removal.

Objective:To evaluate the efficacy and safety of dl-3-butylphthalide ( NBP) injection and soft capsules in the treat-ment of acute middle cerebral artery infarction. Methods:Sixty-one patients with acute cerebral infarction in the left middle cerebral artery in 72 hours of onset of ischemic stroke with score of 5-25 according to the national institutes of health stroke scale ( NIHSS) were randomly divided into the observation group (n=31) and the control group (n=30). The control group was treated with the routine treatment, while the observation group was sequentially treated with NBP injection and soft capsules additionally. The treatment course was 90 days. Before the treatment, the NIHSS score was evaluated in both groups to compare the neurologic impairment degree. After the treatment, the daily living skills assessment was performed by Barthel index ( BI) and modified Rankin score ( mRS) , and the ad-verse reactions were recorded. Results:Before the treatment, the NIHSS score in the two groups had no statistical significance ( P>0. 05). After the treatment, the BI in the observation group and the control group was (88. 55 ± 16. 74) and (70. 67 ± 26. 18), and mRS was (1. 87 ± 1. 02) and (2. 53 ± 1. 40), respectively, suggesting the observation group had more favorable outcome than the con-trol group (P≤0. 05). The incidence of adverse reactions had no significant difference between the groups. Conclusion: dl-3-Bu-tylphthalide sequential therapy should be regarded as an effective and safe method for acute cerebral infarction, which can improve the daily living skills and 90-day outcome of patients.

Objective To explore whether quercetin-loaded PEG-PE micelles(M-Q) can synergize the growth-in-hibitory activity of adriamycin prepared ( ADR) by reversing the drug resistance of MCF-7 ADRr breast cancer cells in vitro.Methods M-Q was prepared by adding saline to lipid film containing quercetin and PEG-PE.The size of M-Q was characterized by dynamic light scattering ( DLS) .The inhibition of MCF-7 ADRr cells was evaluated by MTS assay after incubation with M-Q and ADR.Results The incorporation efficiency of quercetin by the micelles was above 74%.The average size of M-Q was 11.11 nm.Compared with the quercetin dissolved in ethanol , M-Q more effectively reversed the drug resistance of MCF-7 ADRr cells in vitro.Conclusions PEG-PE micelles may potentially deliver quercetin to cancer cells for reversal of drug resistance .