Properties of a liposomes-mediated thermo-sensitive alginate/alpha-tricalcium phosphate/collagen Ⅰ composite hydrogel / 中国组织工程研究

BACKGROUND: The thermo-sensitive composite hydrogels have gained increasing interest in bone regeneration domain due to their biomimetic extracellular matrix (ECM) structure, good biocompatibility, minimal invasive performance and in situ molding. OBJECTIVE:To prepare a thermo-sensitive injectable alginate/α-tricalcium phosphate (α-TCP)/collagen I (Alg/TCP/Col) composite hydrogel and explore its characterization. METHODS:Ca-carrying interdigitation-fusion vesicles (Ca-IFVs) were prepared. The liposomes carrying the optimal concentration of calcium ions were selected for the following experiments by investigating their encapsulation efficiency and drug loading rate. Alg/TCP/Col precursor solution (Alg or Alg/TCP precursor solution) was mixed with Ca-IFVs at 37℃ in different proportions (5, 10, 15, 20) to prepare thermosensitive hydrogels. The structure, rheology behavior, volume swelling ratio, and mechanical properties of the composite hydrogel were observed. MC3T3-E1 cells were co-cultured with Alg/TCP/Col, Alg, and Alg/TCP hydrogels, respectively. Then, morphology of the cells was observed by confocal microscopy at 1, 3, 7 days after co-culture. RESULTS AND CONCLUSION:(1) The pore size of the freeze-dried hydrogel was 50-100 μm, and TCP particles uniformly adhered to the surface of the Alg/TCP hydrogel surface. The Alg/TCP/Col hydrogel was a dense aggregate with collagen fibers in contrast to the Alg/TCP hydrogel. (2) The Alg/TCP/Col hydrogel exhibited a suitable phase transition temperature (Tm) between 35-39℃. (3) The volume swelling ratio of the hydrogel was increased with the increase of Ca-IFVs size. When the α-TCP complex was added into the Alg/TCP hydrogel, the swelling ratio decreased slightly. Alg/TCP/Col hydrogel exhibited a higher swelling ratio than the Alg/TCP hydrogel. (4) When the mixture ratio of precursor solution to liposome was 10, the compressive modulus of Alg/TCP/Col hydrogel and Alg/TCP hydrogel was significantly higher than that of the Alg hydrogel (P<0.05). (5) When the mixture ratio of precursor solution to liposome was 10, round MC3T3-E1 cells were observed on the Alg hydrogel; the cells on the surface of the Alg/TCP hydrogel were scattered and tended to extend; the cells on the surface of the Alg/TCP/Col hydrogel had a stress-extended morphology, and grew into the hydrogel, and meanwhile, the cell number increased significantly. To conclude, the liposome-mediated Alg/TCP/Col has good mechanical properties and cytocompatibility.

Comparison of the effect between minimally invasive surgery transforaminal lumbar interbody fu-sion and posterior lumbar interbody fusion in treatment of recurrent lubar intervertebral disc pro-trusion / 新乡医学院学报

Objective To compare the clinical effect of minimally invasive surgery transforaminal lumbar interbody fu-sion(MIS-TLIF)and posterior lumbar interbody fusion(PLIF)in the treatment of recurrent lumbar intervertebral disc hernia-tion(LIDH). Methods Twenty-nine patients with recurrent LIDP were selected from May 2014 to May 2016 in Weifang Peo-ple's Hospital and the clinical data were analyzed retrospectively. Thirteen patients were given MIS-TLIF(MIS-TLIF group) and sixteen patients were given PLIF(PLIF)group. The operative incision length,intraoperative bleeding volume,postoperative drainage volume,hospitalization time and complications were compared between the two groups. The lumbar function was evalu-ated with the Japanese Orthopaedic Association(JOA)score standard,and the clinical effect was compared between the two groups according to the modified Macnab standard one year after treatment. Results The operativeincision length,intraopera-tive bleeding volume,postoperative drainage volumeand hospitalization time in MIS-TLIF group were significantly less than tho-sein PLIF group (P < 0. 05). The preoperative JOA score of lumbar function in PLIF group and MIS-TLIF group was 7. 9 ± 1. 9 and 8. 0 ± 1. 6 respectively,it was 24. 0 ± 2. 7 and 24. 2 ± 2. 5 respectively at one year after treatment,there was no significant-difference in the JOA score between the two groups before and one year after operation (P > 0. 05). The JOA score atone year after operation was significantly higher than that before operation in the two groups (P < 0. 05). According to the modified Macnab standard one year after treatment,the fineness rate of the patients in PLIF group was 87. 50％(14 / 16),the fineness rate of the patients in the MIS-TLIF group was 84. 62％(11 / 13). There was no significant difference in the fineness rate be-tweenthe two groups (χ2 = 1. 380,P > 0. 05). The incidence of postoperative complications in the MIS-TLIF group and PLIF group was 7. 7％(1/ 13)and 6. 3％ (1/ 16)respectively,there was no significant difference in the incidence of postoperative complications between the two groups (χ2 = 0. 020,P > 0. 05). There were 8 cases (61. 5％)with gradeⅠfusion and 5 cases (38. 5％)with gradeⅡfusion in MIS-TLIF group,there were 9(56. 3％)with gradeⅠfusion and 7(43. 8％)with gradeⅡfu-sion,there was no significant difference in the constituent ratio with gradeⅠandⅡfusion between the two groups (χ2 = 0. 080, P >0. 05). Conclusion MIS-TLIF in treatment of recurrent LIDH has the advantages of less incision,less intraoperative bleed-ing,less postoperative drainage and shorter hospitalization time;and the clinical effect of MIS-TLIF is similar to that of PLIF.

In vitro study on biomechanical comparison between cervical arthroplasty and fusion / 医用生物力学

Objective To analyze biomechanical properties of cervical spine after anterior cervical discectomy and fusion (ACDF) and total disc replacement (TDR) surgery. Methods Twelve cadaveric cervical spines (C2-T1) were adopted, and the motion and load distributions of the cervical segments under intact state and after ACDF and TDR surgery were tested using a three-dimensional (3D) optoelectronics measurement system. All the tests were carried out with displacement control in directions of flexion (Flex), extension (Ext), left bending (LB), right bending (RB), left rotation (LR) and right rotation (RR). Motion characteristics of the normal cervical spine and the implant were also discussed. Results In TDR-treated specimens, range of motion (ROM) was well preserved and could restore to the normal ROM distributions, especially in Flex/Ext and LR/RR direction. While in ACDF-treated specimens, ROM presented a large decrease as much as to 73.41% under the same condition compared with TDR, and ROM distributions were also changed obviously in other motions for the segments. Significant changes of ROM in LB/RB direction occurred in both TDR and ACDF group, which were up to 45.92% and 108.06%, respectively. The experimental data indicated that the normal motion of cervical spines was a 3D coupled motion, especially in LB/RB direction, where a 35% rotation around X-axis existed. The cervical spine could recover close to normal coupled motion after TDR surgery. Conclusions TDR surgery can restore the physiological motion of cervical spines more close to the normal state, especially in Flex/Ext and LR/RR direction. The study provides a theoretical basis and quantitative reference for TDR and ACDF surgery in clinic.

Recent advances about finite element applications in spine biomechanics / 医用生物力学

This article reviews the application of finite element method in spine biomechanics during the last three years. Major progress in both finite element model improvement of detailed microstructure, personalized vertebrae parameter weights, new accurate calibration method, automated modeling approach and spine biomechanics-related applications including implant design assessment, inter-vertebral disc biomechanics, biomechanics of abnormal spinal structure, dynamic simulation are classified and summarized. Future development of finite element method being applied in trauma mechanism, surgery simulation and drug evaluation is also discussed.

Analysis of de novo copy number variations in a family affected with autism spectrum disorders using high-resolution array-based comparative genomic hybridization / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze de novo copy number variations (CNVs) in a Chinese family affected with autism spectrum disorders (ASD).</p><p><b>METHODS</b>Affymetrix Cytogenetics Whole Genome 2.7M Array assay was performed to identify potential CNVs in four members from the family.</p><p><b>RESULTS</b>A total of 89 de novo CNV regions were identified in the autistic siblings. The CNV regions in total have exceeded 1/1000 of the lengths of chromosomes 5, 11 and 14. In addition, de novo CNV regions were also identified at 3p26.1, 4q22.2, and 5p15.2, which encompassed 10 genes associated with nerve development including GRM7, GRID2 and CTNND2.</p><p><b>CONCLUSION</b>A number of nerve development associated genes were at the de novo CNV sites, which may provide new clues for genetic research of ASD. High-resolution array-comparative genomic hybridization is an effective method for detecting submicroscopic chromosomal imbalances.</p>

The biomechanical study and clinical application of monosegmental pedicle instrumentation by endplate method in the fracture vertebrae for thoracolumbar fracture / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the biomechanical and clinical effect of the treatment of thoracolumbar fracture with monosegmental pedicle instrumentation in the fracture vertebrae by endplate method.</p><p><b>METHODS</b>Twenty-four porcine thoracolumbal spinal model, divided into four groups randomly, compared the stability of these four groups through pull-out testing. Retrospective study of 49 patients with thoracolumbar fracture who were treated with this technique, to observe the fusion of bone graft, the height of the anterior and posterior range, the angle of kyphosis and the volume of spinal canal, the loss of rectification, low back pain, and the limitation of activity of lumbar.</p><p><b>RESULTS</b>The endplate method group is more stability than the parallel method group, and the pedicle screw in the fracture vertebrae can get enough stability. After operation all 49 cases achieved satisfactory reduction, strong bone fusion, no reduction loss, no refractoriness low back pain, limitation of motion of lumbar et al.</p><p><b>CONCLUSION</b>Monosegmental pedicle instrumentation by endplate method in the fracture vertebrae for thoracolumbar fracture can get enough extraction stability, and get satisfied clinical effect.</p>

An in vitro experimental study for 3D motion analysis of the cervical spine with the ACP / 中国医疗器械杂志

A set of system for in vitro testing and analyzing the 3D motion in the cervical spine specimen before and after the ACP's (anterior cervical plates) implantation is introduced in this paper. Six porcine specimens with C3 - C6 mounted by the custom clamp were used to mimic human physiological cervical motions. A non-contact real-time measurement system based on CCD was used to track segmental cervical motion signals during the motion. A Matlab program based on multibody dynamics was processed to give the angle changes between adjacent vertebras during the motion. The experimental results show that the methodology can appraise the clinical properties of the ACP effectively.

The expression of Nestin and C-kit in gastrointestinal stromal tumors / 中华消化杂志

0.05).The Nestin and C-kit expressions can be detected in all cases of GISTs by RT-PCR and Western Blot.Conclusion In conjunction with C-kit,Nestin may be a useful marker for diagnosis of GISTs but it cannot be used as a tumor differentiation index.