Posteromedial and anterolateral approaches for posteromedial condylar tibial plateau split fracture combined with lateral compartment depression / 中华创伤杂志

Objective To evaluate the clinical results of posteromedial supine approach plus anterolateral approach for treatment of posteromedial condylar tibial plateau split fracture combined with lateral compartment depression.Methods A retrospective analysis was done on 48 cases of posteromedial condylar tibial plateau split fracture with lateral compartment depression operated through posteromedial supine plus anterolateral approaches from February 2011 through March 2013.There were 37 men and 11 women,aged 15-67 years (mean,42.5 years).Fracture occurred at the left side in 31 cases and at the right side in 17 cases.Interval between injury and operation ranged from 5 to 16 days (mean,8.7 days).Reconstructive or T-shaped plates were used for posteromedial condylar split tibial plateau fracture.Anatomical or locking compression plates were used for lateral compartment depression,but autogenous ilium bone grafting was performed laterally when bone defect was obvious.Results Average operation time was 2.8 hours (range,2-3.5 hours) and average length of stay was 21 days (range,12-45 days).All cases were followed up for mean 12.8 months (range,5-25 months).All fracture healed from 4 to 8 months (mean,6.7 months).Mean Rasmussen score for radiological results was 16.9 points (range,16-18 points) immediately after operation.Hospital for special surgery (HSS) knee score averaged 86.4 points (range,76-95 points) 8 months after bone healed,indicating the excellent results in 27 cases,good in 16 cases,fair in 4 cases and poor in 1 case with a good to excellent rate of 90％.At the last follow-up,postoperative knee range of motion averaged-5°-135°.All incisions healed primarily without vascular nerve injury and implant loosing or breakage.There was an extension lag in 1 case with knee range of motion of 20°-130° and osteoarthritis in 1 case,but both were improved with non-operation therapy.Conclusion Posteromedia] supine plus anterolateral approaches are suitable for posteromedial condylar tibial plateau split fracture with lateral compartment depression,for the combined approaches gain advantages of easy operation,good reduction,rigid fixation,few soft-tissue complications and satisfactory clinical results.

Effects of sintered bone modified with surface mineralization/P24 peptide composite biomaterial on the adhesion, proliferation and osteodifferentiation of MC3T3-E1 cells / 生物医学工程学杂志

In the present research, the effects of sintered bone modified with surface mineralization/P24 peptide composite biomaterials on the adhesion, proliferation and osteodifferentiation of MC3T3-E1 cells were investigated. The experiments were divided into three groups due to biomaterials used: Group A (composite materials of sintered bone modified with surface mineralization and P24, a peptide of bone morphogenetic protein-2); Group B (sintered bone modified with surface mineralization) and Group C (sintered bone only). The three groups were observed by scanning electron microscopy (SEM) before the experiments, respectively. Then MC3T3-E1 cells were cultured on the surfaces of the three kinds of material, respectively. The cell adhesion rate was assessed by precipitation method. The proliferative ability of MC3T3-E1 cells were measured with MTT assay. And the ALP staining and measurement of alkaline phosphatase (ALP) activity were performed to assess the differentiation of cells into osteoblasts. The SEM results showed that the materials in the three groups retained the natural pore structure and the pore sizes were in the range between 200-850 μm. The adhesive ratio measurements and MTT assay suggested that adhesion and proliferation of MC3T3-E1 cells in Group A were much higher than those in Group B and Group C (P < 0.05). The ALP staining and ALP activity of MC3T3-E1 cells in Group A were significantly higher than those in Group B and Group C (P < 0.05). The sintered bone modified with surface mineralization/P24 composite material was confirmed to improve the adhesion rate and proliferation and osteodifferentiation of MC3T3-E1 cells, and maintained their morphology.

The posterior approach combined with pedicle screw fixation for the treatment of lower cervical fractures and dislocation / 中华骨科杂志

Objective To evaluate the feasibility of using the posterior approach with cervical pedicle screw fixation technique for the treatment of lower cervical spine fractures and dislocations.Methods Thirty patients suffered lower cervical fractures and dislocations were retrospectively analyzed,and they were underwent cervical pedicle screw system fixation surgery from January 2010 to December 2012.There were 22 males and 8 females,with an average age of 41 years (range,24-61 years).Eight injuries were located at C4,5,12 at C5,6,and 10 at C6.7.According to the American Spinal Cord Injury Association (ASIA)impairment scale,8 cases were grade A,12 were grade B,5 were grade C,3 were grade D,and 2 were grade E.Results Reduction and fixation of the injured segments were performed via a posterior approach in all 30 patients.One hundred and forty pedicle screws were inserted successfully in all patients on the postoperative radiographic and CT scans.All the patients were followed up for 3-23 months,with the average of 11 months.According to the ASIA impairment scale,eight cases with grade A were still grade A,but the feeling and movement improved obviously.Ten grade B improved to grade C and the rest cases were complete recovery after operations.During the course of the follow up,solid bone union was achieved in all patients,and there were no hardware failures.All the patients' postoperative MRI showed disappearance of the spinal cord compression after reduction in all cases.Conclusion For the patients of lower cervical fractures and dislocation,the first choice of operation should be the posterior approach reduction and fixation with cervical pedicle screw.The correct lengthwise traction method could unblock the locked facet effectively,and prevent the retrusion of disc and the further injury of spinal cord.For the patients of disc disruption,the posterior approach could be used only.The cervical pedicle screw system could provide three-dimensional reduction of the injured cervical segments and the adequate mechanical strength.The posterior approach combined with pedicle screw fixation is feasible and effective for the treatment of lower cervical fractures and dislocation.

Study on preparation and physicochemical properties of surface modified sintered bone / 生物医学工程学杂志

The aim of this study is to investigate a new method for preparing a biomimetic bone material-surface modified sintered bovine cancellous bone, and to improve its bioactivity as a tissue engineering bone. The prepared sintered bovine cancellous bones with the same size were randomly divided into two groups, immersing in 1 and 1. 5 times simulated body fluid (SBF), respectively. The three time periods of soak time were 7, 14, and 21 days. After sintered bone was dried, the surface morphology of sintered bone and surface mineralization composition were observed under scanning electron microscopy (SEM). By comparing the effect of surface modification of sintered bone materials, we chose the most ideal material and studied its pore size, the rate of the porosity, the compress and bend intensity. And then the material and the sintered bone material without surface modification were compared. The study indicated that sintered bone material immersed in SBF (1.5 times) for 14 days showed the best effect of surface modification, retaining the original physico-chemical properties of sintered bone.

Advancement in stimuli-sensitive drug delivery system / 国际生物医学工程杂志

Stimuli-sensitive drug delivery system (SSDDS) is an novel drug delivery carrier.It is sensitive to either the internal physiopathologic changes (pH,temperature) of the body or external stimulus signal (ultrasound,magnetic signal) and controls the release of the drugs that it carries according to the variation of physicochemical property which stimulated by the signals.SSDDS can be prepared from hydrogels,liposomes and magnetic nanoparticles.In contrast to non-stimuli-responsive drug delivery system,SSDDS has remarkable advantages including feedback regulation,stronger controllability and targeting therapy.This paper will review the advancement in stimuli-responsive drug delivery system in recent years.

Different responses to mechanical injury in neonatal and adult ovine articular cartilage / 中华风湿病学杂志

ObjectiveTo investigate the molecular response of adult and neonate ovine articular cartilage to acute mechanical injury.MethodsAn established in vitro model was used to compare gene expression difference of ovine articular cartilage explants at different developmental stages 24 hours after mechanical injury and the gene expression was compared between these models and that of the uninjured controls by microarray analysis.Total RNA was isolated from the tissue samples,linearly amplified,and applied to a 15 208 Ovine probes cDNA microarray(Agilent).Validation for selected genes(PPARγ,GRO TNC and LDHA) was obtained by real-time polymerase chain reaction.Comparisons between groups were performed by variance analysis.ResultsThere was significant difference in gene expression in adult and neonatal ovine articular cartilage after mechanical injury.Eighty-six genes were significantly manipulated at least 2-fold following mechanical injury for neonate sheep and 83 genes for adult sheep (P＜0.05).Conclusion Our findings indicate that mechanical injury to adult and neonatal ovine articular cartilage results in the activation of a series of signaling responses.We could identify four significant genes that are up or downregulated in response to acute mechanical injury.Significant functional clusters including genes associated with wound healing,articular protection,repair integration,and energy metabolism.Of these,PPARG could be specifically identified as novel target molecules and potential chondroprotective agent involved in traumatic cartilage injury and cartilage integrated repair.

Research progresses in nano-hydroxyapatite biomimetic bone materials / 国际生物医学工程杂志

Nano-hydroxyapatite biomimetic bone materials have become a hotspot in the field of tissue engineering research due to the similarity of the structure and composition to natural bone. This article describes a variety of preparation of nano-hydroxyapatite and synthesis of nano-hydroxyapatite composite, as well as the properties of nano-hydroxyapatite composite materials. Through surface-modification nanohydroxyapatite composite materials will have a potential application foreground including bone defects repair,drug carrier for cancer treatment. In this paper, research progress of nano-hydroxyapatite biomimetic bone materials in recent years were reviewed.

Angiogenesis induced with neotype amphiphic peptide / 生物医学工程学杂志

The angiogenesis induced with neotype amphiphilic peptide containing Isoleucine-Lysine-Valine-Alanine-Valine (IKVAV) was explored in vivo. The peptide was self-assembled into hydrogel, confirmed using transmission electron microscopy (TEM). One millilitre of 10 mg/ml peptide (experiment group, EG) and 16.67% gelatin (control group, CG) were injected subcutaneously beside rat backbone. The systemic response and local skin were observed one week after injection. The specimens were harvested two weeks later and immunohistochemically examined for vascular endothelial growth factor (VEGF). TEM showed that hydrogel was composed of interconnected nanofibers. The inflammatory reaction and necrosis of local skins were not found one week after injection. Lots of capillary vessels with complete wall were found within self-assembled peptide hydrogel, with erythrocytes noted inside the vessels in EG; the capillary vessels or erythrocytes were not found in the gelatin in CG. The immunohistochemical detection revealed VEGF-positive cells in EG, which were not found in CG. The self-assembly hydrogel from IKVAV-containing peptide was able to induce the angiogenesis in vivo.

Research progress of effects of neurotrophic factors in the repair of spinal cord injury / 国际生物医学工程杂志

Spinal cord injury(SCI) is a serious nervous system trauma,which may consequently lead to various degrees of paralysis and toilet obstacles,and its disability and the high cost heavily burdened the families and community.Therefore,the research on spinal cord tissue regeneration and the repair after injury has important practical significance.A large number of experimental studies have shown that neurotrophic factor plays an important role in the nerve tissue repair process.This article reviews new research progress about the effects of neurotrophic factor in this field.

Effect of IKVAV peptide nanofiber on proliferation, adhesion and differentiation into neurocytes of bone marrow stromal cells / 华中科技大学学报（医学）（英德文版）

This study examined the effect of IKVAV peptide nanofiber on proliferation, adhesion and differentiation into neurocytes of bone marrow stromal cells (BMSCs). IKVAV Peptide-amphiphile was synthesized and purified. Then, hydrogen chloride was added to the diluted aqueous solutions of PA to induce spontaneous formation of nanofiber in vitro. The resultant samples was observed under transmission electron microscope. BMSCs were cultured with IKVAV peptide nanofiber. The effect of IKVAV nanofiber on the proliferation, adhesion and induction differentiation of BMSCs was observed by inverted microscopy, calcein-AM/PI staining, cell counting and immunofluorescence staining. The results demonstrated that IKVAV peptide-amphiphile could self-assemble to form nanofiber gel. BMSCs cultured in combination with IKVAV peptide nanofiber gel grew well and the percentage of live cells was over 90%. IKVAV peptide nanofiber gel exerted no influence on the proliferation of BMSCs and could promote the adhesion of BMSCs and raise the ratio of neurons when BMSCs were induced to differentiate into neurocytes. It is concluded that BMSCs could proliferate and adhere well and yield more neurons during when induced to differente into neurocytes on IKVAV peptide nanofiber gel.

Biocompatibility of KLD-12 peptide hydrogel as a scaffold in tissue engineering of intervertebral discs in rabbits / 华中科技大学学报（医学）（英德文版）

KLD-12 peptide with a sequence of AcN-KLDLKLDLKLDL-CNH(2) was synthesized and its biocompatibility was assessed in animals. Rabbit MSCs were cultured in the hydrogel for 2 weeks. Live cells were counted by using Calcein-AM/PI fluorescence staining. MTT was employed to assess the viability of MSCs cultured in KLD-12 peptide solution of 0.01%, 0.03%, and 0.05%. Hemolysis test, skin irritation test and implantation test were conducted to evaluate its biocompatibility with host tissues. Our results demonstrated that the MSCs in hydrogel grew well and maintained round shape. Cell survival rate was 92.15% (mean: 92.15%+/-1.17%) at the 7th day and there was no difference in survival rate between day 7 and day 14. Cell proliferation test showed that the A value of the KLD-12 solutions was not significantly different from that of control groups (complete culture media) (P>0.05) at the 24th and 48th h. The hemolysis rate of KLD-12 solution was 0.112%. Skin irritation test showed that the skin injected with KLD-12 solution remained normal and the score of skin irritation was 0. The histological examination with HE staining exhibited that the skin layers were clear and there was no infiltration with neutrophilic granulocytes and lymphocytes. It is concluded that KLD-12 peptide hydrogel had a good biocompatibility with host rabbit and MSCs, and KLD-12 peptide hydrogel can provide an appropriate microenvironment for MSCs.

Neural stem cells induced by neotype three-dimensional polypeptide-based self-assembled hydrogel / 生物医学工程学杂志

The amphiphilic polypeptide (PA) was self-assembled into three-dimensional (3-D) porous complex of hydrogel and cells with the addition of NSCs-containing DMEM/F12. Cell differentiation in the surface and that within hydrogel were described. Cells harvested from the cerebral cortex of neonatal mice were triturated and cultivated in serum-free media. 1wt% PA was added into same volume of DMEM/F12 with cell concentration of 1 x 10(5)/ml and self-supported into 3-D hydrogel-cell composition; cells suspended within hydrogel being maintained (Experiment group, EG). lwt% PA was self-assembled into two-dimensional (2-D) hydrogel films triggered by addition of DMEM/F12, and then 1 x 10(5)/ml NSCs was seeded in the surface of films (Control group, CG). Cells in EG and CG were incubated in serum-free media for two weeks and stained with immunocytochemistry methods. TEM showed that the hydrogel derived from PA was composed of network nanofibers with their diameter ranging from 3 to 5 nm and length ranging from 100 nm to 1. 5 microm. Above 50% of cells obtained were Nestin positive cells. LSCM observations demonstrated that above 90% of cells survived two days after incubation within hydrogel, and were differentiated into NF and GFAP positive cells one week after incubation, their differentiation rates were 50% +/- 4.2% and 20% +/- 2.8% respectively; however, cells in CG were also differentiated into NF and GFAP positive cells, their differentiation rates were only 40% +/- 3.4% and 31% +/- 2.3% separately. Peptide-based hydrogel was able to provide 3-D environments for cell survival and induce primarily the differentiation of NSCs into neurons. Our data indicated that peptide-directed self-assembly of hydrogels was useful and it served as the neotype nerve tissue engineering scaffolds.

Hydrogel self-supported from the neotype of amphiphilic peptide / 生物医学工程学杂志

The neotype of amphiphilic oligopeptide (C16 H31 O-AAAGGGGDDIKVAV) was synthesized. The framework of three-dimensional and porous hydrogel self-assembly from the amphiphilic oligopeptide on different conditions was explored. The peptide, whose molecular weight (MW) and purity were detected by Mass Spectrometer (MS) and High Performance Liquid Chromatograph (HPLC) respectively, was synthesized in solid phase methods. Peptide was dissolved in 0.1 mol/L Sodium Hydroxide (NaOH) solution. 200 microl of 10, 2, 1, 0.5 wt% peptide solutions, which were prepared respectively, were added into the same volume of DMEM/F12, or placed into the vapor of 10 mol/L Hydrochloric acid (HCl), or were used to coat in the surface of coverslip and set into the baking oven at 37 degrees C. The self-assembly hydrogel was examined with transmission electron microscope (TEM) and scanning electron microscope (SEM). MS showed that peptide MW was 1438.31. HPLC testified that the peptide purity was 96%. The peptide solution was self-supported into hydrogel triggered with DMEM/F12 in few seconds, or the thin hydrogel after two hours in the vapor of 10 mol/L HCl, or not hydrogel in the baking oven at 37 degrees C. SEM showed that the hydrogel self-assembly from 10 wt% peptide solution was composed of nanofibers that ranked in layers where there were thick voids. TEM showed that the hydrogel self-assembly from 2, 1, 0.5 wt% peptide solution comprised woven network nanofibers, that the nanofibers of hydrogel self-supported from 1 wt% peptide solution varied from 3 to 6 nm in diameter and 100 nm to 1.5 um in length, that the nanofibers of hydrogel self-supported from 2 wt% peptide solution ranked closely, and there were big voids within the thin nanofibers of hydrogel self-supported from 0.5 wt% peptide solution. The amphiphilic oligopeptide was synthesized and self-organized successfully into porous hydrogel characterized as "intelligent" tissue engineering scaffolds containing the bioactive ligand, which was triggered by DMEM/F12.

The cytocompatibility of self-assembly hydrogel from the neotype of amphiphilic peptide with neural stem cells / 生物医学工程学杂志

Neural stem cells (NSCs) cultured in vitro were implanted within three-dimensional (3D) and self-assembly hydrogel from IKVAV-containing peptide. The cytocompatibility of hydrogel with NSCs was explored. Neural cells harvested from the cerebral cortex of neonatal mice were dissociated mechanically and cultivated in serum-free media, and were immunohistochemically examined for Nestin, NSE (neuron specific enolase) and GFAP (Glial fibrillary acidic protein); the self-assembly hydrogel from 1 wt% amphiphilic peptide was formed with the addition of DMEM/F12 and observed under transmission electron microscope (TEM); 1 x 10(5) /ml NSCs implanted within hydrogel (3D culture system) and seeded onto the surface of coverslips covered with polylysine (two-dimensional culture system, 2D culture system) respectively were incubated without serum at 37 degrees C in 5% CO2 and 95% air. Then the cells in 3D culture system and 2D one were double-labeled with DAPI/Brdu and observed under fluorescence microscope. The Nestin-positive cells were found, and they were able to differentiate into NSE-positive neuron- like cells and GFAP-positive glial-like cells, TEM showed that the hydrogel derived from 1 wt% peptide solution was composed of nanofiber network with the fiber diameters ranging from 3 to 6 nm and the fiber length warying from 100 nm to 1.5 microm, NSCs labeled with Brdu in 2D system were thinly scattered, and those in 3D system formed many neurospheres; the positive rate in 3D was much higher than that in 2D system (P < 0.001). The self-assembly hydrogel from the amphiphilic peptide containing IKVAV sequence had good cyto-compatibility and promoted the proliferation of NSCs.

Advances in the research of gene therapy for chondral lesions / 国际生物医学工程杂志

Cartilage injury has a very limited capacity of recovery by itself due to the lack of blood vessel in cartilage tissues. Current studies indicate that many kinds of cytokines have the function of promoting cartilage formation or repairing the injured cartilage with cartilage-like tissues. Cell-mediated transfer of the respective genes may ideally combine the supply of a chondrogenic cell population with the production of certain factors se-creted from the lesion and to promote the repairing of the lesion, which is considered the best treatment. Gene therapy based on this technology has developed rapidly in recent years. This review aims to summarize some of the development of the research in the field.

Application development of rapid prototyping technology in orthopedics / 国际生物医学工程杂志

Rapid prototyping technology, a kind of novel digital prototyping technology developed in mid-1980s based on a principle of discrete and accumulation, which fabricates a prototype by accurate accumulation of material according to the CAD models or CT data under the control of the computer without any other device. In recent years, it has shown a great application prospect in the field of orthopedics combined with three-dimensional image reconstruction of spiral CT and MRL In this article, review is given on the application development of rapid prototyping technology in orthopedics, such as organ model preparation and surgical planning, customized implant and bone tissue engineering porosity scaffold fabrication.

Observing hemodynamic changes in the spinal cord after acute spinal cord injury / 中华物理医学与康复杂志

Objective To observe any changes in spinal cord hemodynamics after spinal cord injury and to investigate their mechanism. Methods Twenty female Sprague-Dawley rats were divided into a control group and a moderate injury group,10 rats in each group.A rat model of spinal cord injury caused by moderate compression was established using Nystrom's method.Changes in the velocity and volume of blood flow and in the diameters of vessels of the spinal cord were monitored for 6 hours using laser speckle imaging. Results No changes in the velocity or volume of blood flow or in the diameter of vessels were observed in the control group,but all of these indices diminished significantly in the injury group. Conclusions Laser speckle imaging can be used to monitor changes in spinal cord hemodynamics.Such changes after acute spinal cord injury indicate progressive post-injury ischemia.The occlusion of veins may be an important contributor to post-injury ischemia.

Preparation and characterization of oligopeptide modified hydroxyapatite crystal scaffolds / 国际生物医学工程杂志

Objective To prepare a new osteoinduction hydroxyapatite crystal material using sintered bovine bone combined with bone morphogenetic protein(BMP2)-derived peptide and type Ⅰ collagen,and to study their biological characteristics for developing biomaterials for orthopaedic tissue engineered bone.Methods Sintered bovine bone combined with BMP2-derived peptide and type Ⅰ collagen was as experimental group.and Sintered bovine bone combined with Type Ⅰ collagen Wag as control group.Formation of hydmxyapatite crystals was inveati gated under environmental scanning electron microscopy(ESEM),energy-dispersive spectroscopy(EDS)and X-ray diffraction(XRD).The ceil-material complex Wag observed and cell adhesion rate on each materials WaS calculated using the method of indirect cell count to evaluate the interaction between cells and materials.Results By ESEM,formation of hydroxyapatite crystals in collagen surface was observed in experimental group but none was observed in control group.By EDS and XRD,the contents of calcium and phosphorus elements from mineralized bone surface were 16.23% and 7.76%respectively.The atom percentages of calcium and phosphorus elements were 6.34%and 3.88%respectively.The cell adhesion rate of experimental group after 24 hours co-culture was significantly higher than that of control group (α＜0.05).Conclusion BMP2-derived peptide can induce the formation of hydroxyapatite crystals at the surface of sintered bovine bone combined with type Ⅰcollagen.It can also elevate the osteoinduction and cell adhesion rate and is an ideal scaffold material by combining with sintered bovine bone for the bone tissue engineering.

Biocompatibility of porous drug implant scaffolds based on 3D printing technology / 国际生物医学工程杂志

Objective To evaluate the biocompatibility of porous drug implant scaffolds prepared by 3D printing technique. Methods Porous drug implant scaffolds were fabricated by 3D printing technique, and a series of tests were carried out to validate the biocompatibility, including acute systemic toxicity, hot source test, local irritation reaction, micronucleus test, muscle implant test and so on. Results The porous drug implant scaffolds showed no acute systemic toxicity, no pyrogenetic effect, no local erythema and edema in local irritation re-action, hemolysis rate of 0.29%, no cellular genetoxic. No local tissue denaturation, necrosis and exclusion were found in intramuscular implant test. Conclusion With good biocompatibility, the porous drug implant scaffold fabricated by 3D printing technique can meet the clinical requirement for biomaterial.

DNA microarray technology and its application advances in articular cartilage research / 国际生物医学工程杂志

DNA microarray generally refers to gene chips. Its basic principle is that a large number of oligonucleotide molecules were fixed on the support, and then hybridized with the labeled samples, and then the chip hybridization signal strength was scanned to determine the number of target in the samples. Gene chips can trace the nucleotide sequence in the samples for testing and analyzing. Its characteristics of high-throughput,rapid and parallel acquisition of biological information are better than that of other traditional gene detection technology. It has been widely used in various fields of medical research. This article reviews the application of DNA microarray technology in the study of orthopedics including biological characteristics, formation and development,injury and repair, degeneration and regeneration of articular cartilage.