Treatment of humeral shaft fractures with different treatment methods: a network meta-analysis of randomized controlled trials.

PURPOSE: Humeral shaft fractures (HSFs) can be treated non-operatively (Non-OP), with open reduction and plate osteosynthesis (ORPO), minimally invasive plate osteosynthesis (MIPO), or with intramedullary nails (IMN). However, the best treatment for HSFs still remains controversial.We performed a network meta-analysis to explore which should be the best method for HSFs. METHODS: The computerized search had been conducted on electronic databases PubMed, EMBASE, Cochrane Library, and Medline from the establishment of the database to the end of December 2022. The quality evaluation of the included literature had been completed by Review Manager (version 5.4.1). Stata 17.0 software (Stata Corporation, College Station, Texas, USA)was used for network meta-analysis.We included randomized controlled trials (RCTs) comparing different treatments to treating HSFs. RESULTS: The pairwise comparison results demonstrated that there was no statistical difference between IMN, MIPO, Non-OP, and ORPO in terms of radial nerve injury and infection, and Non-OP presented significantly more nonunion than ORPO, IMN, and MIPO. However, no statistically significant difference between ORPO, IMN, and MIPO was discovered. The results of the network meta-analysis displayed that surface under the cumulative ranking curve (SUCRA) probabilities of IMN, MIPO, Non-OP, and ORPO in radial nerve injury were 46.5%, 66.9%, 77.3%, and 9.3%, respectively, in contrast, that in infection were 68.6%, 53.3%, 62.4%, and 15.4%, respectively, and that in nonunion were 51.7%, 93.1%, 0.7%, and 54.5%, respectively. CONCLUSION: We came to the conclusion that MIPO is currently the most effective way to treat HSFs. TRIAL REGISTRATION: Name of the registry: Prospero, 2. Unique Identifying number or registration ID: CRD42023411293.

NEL-Like Molecule-1 (Nell1) Is Regulated by Bone Morphogenetic Protein 9 (BMP9) and Potentiates BMP9-Induced Osteogenic Differentiation at the Expense of Adipogenesis in Mesenchymal Stem Cells.

BACKGROUND: BMP9 induces both osteogenic and adipogenic differentiation of mesenchymal stem cells (MSCs). Nell1 is a secretory glycoprotein with osteoinductive and anti-adipogenic activities. We investigated the role of Nell1 in BMP9-induced osteogenesis and adipogenesis in MSCs. METHODS: Previously characterized MSCs iMEFs were used. Overexpression of BMP9 and NELL1 or silencing of mouse Nell1 was mediated by adenoviral vectors. Early and late osteogenic and adipogenic markers were assessed by staining techniques and qPCR analysis. In vivo activity was assessed in an ectopic bone formation model of athymic mice. RESULTS: We demonstrate that Nell1 expression was up-regulated by BMP9. Exogenous Nell1 potentiated BMP9-induced late stage osteogenic differentiation while inhibiting the early osteogenic marker. Forced Nell1 expression enhanced BMP9-induced osteogenic regulators/markers and inhibited BMP9-upregulated expression of adipogenic regulators/markers in MSCs. In vivo ectopic bone formation assay showed that exogenous Nell1 expression enhanced mineralization and maturity of BMP9-induced bone formation, while inhibiting BMP9-induced adipogenesis. Conversely, silencing Nell1 expression in BMP9-stimulated MSCs led to forming immature chondroid-like matrix. CONCLUSION: Our findings indicate that Nell1 can be up-regulated by BMP9, which in turn accelerates and augments BMP9-induced osteogenesis. Exogenous Nell1 may be exploited to enhance BMP9-induced bone formation while overcoming BMP9-induced adipogenesis in regenerative medicine.

The Prodomain-Containing BMP9 Produced from a Stable Line Effectively Regulates the Differentiation of Mesenchymal Stem Cells.

BACKGROUND: BMPs play important roles in regulating stem cell proliferation and differentiation. Using adenovirus-mediated expression of the 14 types of BMPs we demonstrated that BMP9 is one of the most potent BMPs in inducing osteogenic differentiation of mesenchymal stem cells (MSCs), which was undetected in the early studies using recombinant BMP9 proteins. Endogenous BMPs are expressed as a precursor protein that contains an N-terminal signal peptide, a prodomain and a C-terminal mature peptide. Most commercially available recombinant BMP9 proteins are purified from the cells expressing the mature peptide. It is unclear how effectively these recombinant BMP9 proteins functionally recapitulate endogenous BMP9. METHODS: A stable cell line expressing the full coding region of mouse BMP9 was established in HEK-293 cells by using the piggyBac transposon system. The biological activities and stability of the conditioned medium generated from the stable line were analyzed. RESULTS: The stable HEK-293 line expresses a high level of mouse BMP9. BMP9 conditioned medium (BMP9-cm) was shown to effectively induce osteogenic differentiation of MSCs, to activate BMP-R specific Smad signaling, and to up-regulate downstream target genes in MSCs. The biological activity of BMP9-cm is at least comparable with that induced by AdBMP9 in vitro. Furthermore, BMP9-cm exhibits an excellent stability profile as its biological activity is not affected by long-term storage at -80ºC, repeated thawing cycles, and extended storage at 4ºC. CONCLUSIONS: We have established a producer line that stably expresses a high level of active BMP9 protein. Such producer line should be a valuable resource for generating biologically active BMP9 protein for studying BMP9 signaling mechanism and functions.

Clinical Features and Surgical Outcomes of Spinal Hamartomas: Surgical Treatment of 8 Patients.

OBJECTIVE: Rarely do spinal hamartomas receive attention in the literature, and the majority of previous studies consist of case reports. The purpose of this report, then, is to provide a more accurate diagnosis and treatment of spinal hamartomas by presenting the clinical and surgical outcomes of 8 cases. METHODS: The researchers conducted a retrospective analysis of the data for 8 individuals with spinal hamartomas. The 8 patients had undergone both preoperative and postoperative magnetic resonance imaging (MRI) and went through surgery. Radiologic and pathologic criteria were applied to diagnose the spinal hamartomas. The Modified McCormick classification system was used to evaluate neurologic function in these patients. RESULTS: Among the 8 patients, 6 were male and 2 were female, with an average age of 37.4 years. The typical duration of symptoms was 14.5 months. During surgery, all lesions were well-defined and located in the bone marrow. Gross total resection (GTR) was achieved in 6 cases, and the anatomical plane was clearly delineated, and subtotal resection (STR) was achieved in 2 cases. None of the patients took postoperative radiotherapy. 14.5 months was the average follow-up period during this time, and MRI did not observe the recurrence or regeneration of residual tumors. The McCormick grade was improved in 7 patients and remained stable in 1 patient. CONCLUSIONS: Spinal hamartomas are benign, but they are clinically progressive lesions. Pathology is the basis of accurate diagnosis, and complete preoperative evaluation is crucial for providing suitable treatment and prognosis.

Clinical profile of musculoskeletal injuries associated with the 2008 Wenchuan earthquake in China.

BACKGROUND: The Wenchuan earthquake was an enormous devastating disaster and caused mass casualties. The descriptive analysis presented here serves as a reference not only for present injury intervention but also for future earthquake disaster response. METHODS: A total of 205 patients with a musculoskeletal injury were admitted in two teaching hospitals. We conducted a retrospective review of medical records to document the injury profile, chief complaints, damage locations and types, subsequent treatment, and prognosis. RESULTS: Of the 205 patients, fracture was the major type of injury (78.0%). Forty patients were determined to have crush injuries and 19 patients had crush syndromes. Open fractures, multiple fractures and comminuted fractures were common. Fracture-associated neural injuries and trauma-associated infections were also common. Surgical treatments included debridement, bone traction, external fixation, open reduction and internal fixation, and spinal fixation. All the patients were effectively treated with few complications, a low deformity rate and no death. CONCLUSION: For emergency conditions after a major earthquake, pre-hospital emergency care is highly important. After the patients are transported to the hospital, we should plan individualized treatment according to the patients' respective clinical features, and at the same time, prevent and cure the related complications in a timely manner in order to reduce mortality and disability rates.

Superior versus anteroinferior plating of displaced midshaft clavicular fracture in patients older than 60 years.

Objective To compare superior versus anteroinferior plating for displaced midshaft clavicular fracture in elderly patients. Methods We retrospectively compared the functional result, parameters, and perioperative course of displaced midshaft clavicular fracture in 42 patients >60 years treated with a 3.5-mm reconstruction plate placed superiorly versus anteroinferiorly. Results Groups were similar with regard to age, sex, bone mineral density, cause of injury, and fracture pattern. The superiorly-plated group had a significantly longer operation time and greater blood loss, complications and implant prominence. Constant scores were significantly higher for the anteroinferiorly-plated group than the superiorly-plated group at 3 months postoperatively; however, there was no difference between groups at final follow-up. Conclusion While both anteroinferior and superior plate placement are safe and effective for displaced midclavicular fractures in patients >60 years, the anteroinferior approach involves less operation time, blood loss, complications and implant prominence, and enables faster return to normal activities.

Repair of critical sized cranial defects with BMP9-transduced calvarial cells delivered in a thermoresponsive scaffold.

Large skeletal defects caused by trauma, congenital malformations, and post-oncologic resections of the calvarium present major challenges to the reconstructive surgeon. We previously identified BMP-9 as the most osteogenic BMP in vitro and in vivo. Here we sought to investigate the bone regenerative capacity of murine-derived calvarial mesenchymal progenitor cells (iCALs) transduced by BMP-9 in the context of healing critical-sized calvarial defects. To accomplish this, the transduced cells were delivered to the defect site within a thermoresponsive biodegradable scaffold consisting of poly(polyethylene glycol citrate-co-N-isopropylacrylamide mixed with gelatin (PPCN-g). A total of three treatment arms were evaluated: PPCN-g alone, PPCN-g seeded with iCALs expressing GFP, and PPCN-g seeded with iCALs expressing BMP-9. Defects treated only with PPCN-g scaffold did not statistically change in size when evaluated at eight weeks postoperatively (p = 0.72). Conversely, both animal groups treated with iCALs showed significant reductions in defect size after 12 weeks of follow-up (BMP9-treated: p = 0.0025; GFP-treated: p = 0.0042). However, H&E and trichrome staining revealed more complete osseointegration and mature bone formation only in the BMP9-treated group. These results suggest that BMP9-transduced iCALs seeded in a PPCN-g thermoresponsive scaffold is capable of inducing bone formation in vivo and is an effective means of creating tissue engineered bone for critical sized defects.

A Bayesian network meta-analysis of three different surgical procedures for the treatment of humeral shaft fractures.

BACKGROUND: The optimal surgical procedure for humeral shaft fractures remains a matter of debate. We aimed to establish the optimum procedure by performing a Bayesian network meta-analysis. METHODS: PubMed, EMBASE, the Cochrane Library, and Medline were searched for both randomized controlled trials and prospective studies of surgical treatment for humeral shaft fractures. The quality of the included studies was assessed according to the Cochrane Collaboration's "Risk of bias". RESULTS: Seventeen RCTs or prospective studies were included in the meta-analysis. The pooled results showed that the occurrence rate of radial nerve injury was lowest for minimally invasive plate osteosynthesis (MIPO; SUCRA probability, 95.1%), followed by open reduction and plate osteosynthesis (ORPO; SUCRA probability, 29.5%), and was highest for intramedullary nailing (IMN; SUCRA probability, 25.4%). The aggregated results of pairwise meta-analysis showed no significant difference in radial nerve injury rate when comparing ORPO versus IMN (OR, 1.92; 95% CI, 0.96 to 3.86), ORPO versus MIPO (OR, 3.38; 95% CI, 0.80 to 14.31), or IMN versus MIPO (OR, 3.19; 95% CI, 0.48 to 21.28). Regarding the nonunion, SUCRA probabilities were 90.5%, 40.2%, and 19.3% for MIPO, ORPO, and IMN, respectively. The aggregated results of a pairwise meta-analysis also showed no significant difference for ORPO versus IMN (OR, 0.83; 95% CI, 0.41 to 1.69), ORPO versus MIPO (OR, 2.42; 95% CI, 0.45 to 12.95), or IMN versus MIPO (OR, 2.49; 95% CI, 0.35 to 17.64). CONCLUSION: The current evidence indicates that MIPO is the optimum choice in the treatment of humeral shaft fractures and that ORPO is superior to IMN.

An effective treatment of experimental osteomyelitis using the antimicrobial titanium/silver-containing nHP66 (nano-hydroxyapatite/polyamide-66) nanoscaffold biomaterials.

Effective treatment of osteomyelitis remains a formidable clinical challenge. The rapid emergence of multidrug-resistant bacteria has renewed interest in developing antimicrobial biomaterials using antiseptic silver ions to treat osteomyelitis. However, inadequate local retention and severe cytotoxic effects have limited the clinical use of ionic silver for bone grafts. We recently developed novel porous nano-hydroxyapatite/polyamide 66 (nHP66)-based nanoscaffold materials containing varied concentrations of silver ions (Ag+) (TA-nHAPA66) and oxidized titanium (TiO2), which was added as a second binary element to enhance antibacterial activity and biocompatibility. In this study, we establish a large cohort of rabbit model of experimental osteomyelitis and investigate the in vivo antimicrobial and therapeutic effects of TA-nHP66 biomaterials and their in vivo silver release kinetics. We find the TA-nHP66 scaffolds exhibit potent antibacterial activities against E. coli and S. aureus, support cell adhesion and cell proliferation of pre-osteoblasts, and stimulate osteogenic regulator/marker expression. Moreover, the TA2-nHP66 scaffold exerts potent antibacterial/anti-inflammation effects in vivo and promotes bone formation at the lesion site of osteomyelitis. We further demonstrate that TA2-nHP66 exhibits excellent biosafety profile without apparent systemic toxicities. Therefore, the TA-nHP66 scaffold biomaterials may be further explored as an effective adjuvant therapy for infected bone defects and/or osteomyelitis debridement.

Bone regeneration and infiltration of an anisotropic composite scaffold: an experimental study of rabbit cranial defect repair.

Tissue formation on scaffold outer edges after implantation may restrict cell infiltration and mass transfer to/from the scaffold center due to insufficient interconnectivity, leading to incidence of a necrotic core. Herein, a nano-hydroxyapatite/polyamide66 (n-HA/PA66) anisotropic scaffold with axially aligned channels was prepared with the aim to enhance pore interconnectivity. Bone tissue regeneration and infiltration inside of scaffold were assessed by rabbit cranial defect repair experiments. The amount of newly formed bone inside of anisotropic scaffold was much higher than isotropic scaffold, e.g., after 12 weeks, the new bone volume in the inner pores was greater in the anisotropic scaffolds (>50%) than the isotropic scaffolds (<30%). The results suggested that anisotropic scaffolds could accelerate the inducement of bone ingrowth into the inner pores in the non-load-bearing bone defects compared to isotropic scaffolds. Thus, anisotropic scaffolds hold promise for the application in bone tissue engineering.

Wnt/ß-catenin signaling plays an ever-expanding role in stem cell self-renewal, tumorigenesis and cancer chemoresistance.

Wnt signaling transduces evolutionarily conserved pathways which play important roles in initiating and regulating a diverse range of cellular activities, including cell proliferation, calcium homeostasis, and cell polarity. The role of Wnt signaling in control of cell proliferation and stem cell self-renewal is primarily carried out through the canonical pathway, which is the best characterized among the multiple Wnt signaling branches. The past 10 years has seen a rapid expansion in our understanding of the complexity of this pathway, as many new components of Wnt signaling have been identified and linked to signaling regulation, stem cell functions, and adult tissue homeostasis. Additionally, a substantial body of evidence links Wnt signaling to tumorigenesis of many cancer types and implicates it in the development of cancer drug resistance. Thus, a better understanding of the mechanisms by which dysregulation of Wnt signaling precedes the development and progression of human cancer may hasten the development of pathway inhibitors to augment current therapy. This review summarizes and synthesizes our current knowledge of the canonical Wnt pathway in development and disease. We begin with an overview of the components of the canonical Wnt signaling pathway and delve into the role this pathway has been shown to play in stemness, tumorigenesis, and cancer drug resistance. Ultimately, we hope to present an organized collection of evidence implicating Wnt signaling in tumorigenesis and chemoresistance to facilitate the pursuit of Wnt pathway modulators that may improve outcomes of cancers in which Wnt signaling contributes to aggressive disease and/or treatment resistance.

Transition to resistance: An unexpected role of the EMT in cancer chemoresistance.

Two recent studies provide intriguing evidence that challenges the role of the epithelial-mesenchymal transition (EMT) as a critical mediator of cancer metastasis, while revealing an unexpected role in cancer drug resistance.1,2 While these findings may not settle the EMT's role in metastasis, these studies suggest that targeting the EMT may inhibit both cancer metastasis and chemoresistance.

Bone morphogenetic protein 9 (BMP9) induces effective bone formation from reversibly immortalized multipotent adipose-derived (iMAD) mesenchymal stem cells.

Regenerative medicine and bone tissue engineering using mesenchymal stem cells (MSCs) hold great promise as an effective approach to bone and skeletal reconstruction. While adipose tissue harbors MSC-like progenitors, or multipotent adipose-derived cells (MADs), it is important to identify and characterize potential biological factors that can effectively induce osteogenic differentiation of MADs. To overcome the time-consuming and technically challenging process of isolating and culturing primary MADs, here we establish and characterize the reversibly immortalized mouse multipotent adipose-derived cells (iMADs). The isolated mouse primary inguinal MAD cells are reversibly immortalized via the retrovirus-mediated expression of SV40 T antigen flanked with FRT sites. The iMADs are shown to express most common MSC markers. FLP-mediated removal of SV40 T antigen effectively reduces the proliferative activity and cell survival of iMADs, indicating the immortalization is reversible. Using the highly osteogenic BMP9, we find that the iMADs are highly responsive to BMP9 stimulation, express multiple lineage regulators, and undergo osteogenic differentiation in vitro upon BMP9 stimulation. Furthermore, we demonstrate that BMP9-stimulated iMADs form robust ectopic bone with a thermoresponsive biodegradable scaffold material. Collectively, our results demonstrate that the reversibly immortalized iMADs exhibit the characteristics of multipotent MSCs and are highly responsive to BMP9-induced osteogenic differentiation. Thus, the iMADs should provide a valuable resource for the study of MAD biology, which would ultimately enable us to develop novel and efficacious strategies for MAD-based bone tissue engineering.

A thermoresponsive polydiolcitrate-gelatin scaffold and delivery system mediates effective bone formation from BMP9-transduced mesenchymal stem cells.

Successful bone tissue engineering requires at the minimum sufficient osteoblast progenitors, efficient osteoinductive factors, and biocompatible scaffolding materials. We previously demonstrated that bone morphogenetic protein 9 (BMP9) is one of the most potent factors in inducing osteogenic differentiation of mesenchymal stem cells (MSCs). Here, we investigated the potential use of a biodegradable citrate-based thermosensitive macromolecule, poly(polyethyleneglycol citrate-co-N-isopropylacrylamide) (PPCN) mixed with gelatin (PPCNG) as a scaffold for the delivery of BMP9-stimulated MSCs to promote localized bone formation. The addition of gelatin to PPCN effectively enhanced the cell adhesion and survival properties of MSCs entrapped within the gel in 3D culture. Using the BMP9-transduced MSC line immortalized mouse embryonic fibroblasts (iMEFs), we found that PPCNG facilitated BMP9-induced osteogenic differentiation of iMEFs in vivo and promoted the formation of well-ossified and vascularized trabecular bone-like structures in a mouse model of ectopic bone formation. Histologic evaluation revealed that vascularization of the bony masses retrieved from the iMEFs + PPCNG group was significantly more pronounced than that of the direct cell injection group. Accordingly, vascular endothelial growth factor (VEGF) expression was shown to be significantly higher in the bony masses recovered from the iMEFs + PPCNG group. Taken together, our results suggest that PPCNG may serve as a novel biodegradable and injectable scaffold and carrier for gene and cell-based bone tissue engineering.

Fabrication and Osteogenesis of a Porous Nanohydroxyapatite/Polyamide Scaffold with an Anisotropic Architecture.

Scaffolds are used in bone tissue engineering to provide a temporary structural template for cell seeding and extracellular matrix formation. However, tissue formation on scaffold outer edges after implantation due to insufficient interconnectivity may restrict cell infiltration and mass transfer to/from the scaffold center, leading to bone regeneration failure. To address this problem, we prepared nanohydroxyapatite/polyamide66 (n-HA/PA66) anisotropic scaffolds with axially aligned channels (300 µm) with the aim to enhance pore interconnectivity and subsequent cell and tissue infiltration throughout the scaffold. Anisotropic scaffolds with axially aligned channels had better mechanical properties and a higher porosity (86.37%) than isotropic scaffolds produced by thermally induced phase separation (TIPS). The channels in the anisotropic scaffolds provided cells with passageways to the scaffold center and thus facilitated cell attachment and proliferation inside the scaffolds. In vivo studies showed that the anisotropic scaffolds could better facilitate new bone ingrowth into the inner pores of the scaffold compared to the isotropic scaffolds. The anisotropic scaffolds also had improved vascular invasion into their inner parts, increasing the supply of oxygen and nutrients to the cells and thus facilitating revascularization and bone ingrowth. Enhanced cell and tissue penetration to the scaffold center was observed in the anisotropic scaffolds both in vitro and in vivo, indicating the axially aligned channels positively influenced cell and tissue infiltration. Thus, such scaffolds have great potential for applications in bone tissue engineering.

[Failure cause of posterior approach orthopaedic operation of thoracolumbar hemivertebra and strategies of revision].

OBJECTIVE: To explore the failure cause of posterior approach orthopaedic operation of thoracolumbar hemivertebra, and to summary strategies of revision. METHODS: The clinical data from 9 cases undergoing posterior approach orthopaedic operation failure of thoracolumbar hemivertebra between June 2003 and June 2008, were retrospectively analyzed. There were 5 males and 4 females with a median age of 12 years (range, 1 year and 10 months to 24 years). All malformations were identified as fully segmented hemivertebra from the original medical records and X-ray films, including 2 cases in thoracic vertebra, 5 cases in thoracolumbar vertebra, and 2 cases in lumbar vertebra. The preoperative scoliotic Cobb angle was (45.4 +/- 17.4) degrees, and kyphotic Cobb angle was (29.8 +/- 22.0) degrees. The reason of primary surgical failure were analyzed and spinal deformity was corrected again with posterior revision. RESULTS: All surgeries were finished successfully. The operation time was 3.0-6.5 hours (mean, 4.5 hours), and the perioperative bleeding was 400-2 500 mL (mean, 950 mL). All incisions healed by first intention; no infection or deep venous thrombosis occurred. Numbness occurred in unilateral lower extremity of 1 case postoperatively, and the symptom was relieved completely after treatment of detumescence and neural nutrition. All cases were followed up 12-30 months (mean, 18 months). No pseudoarthrosis and implant failure occurred. The X-ray films showed that the bone grafts completely fused within 8-14 months (mean, 11 months) after operation. The Cobb angles of scoliosis and kyphosis at 1 week after operation and the last follow-up were obviously improved when compared with preoperative ones, showing significant differences (P < 0.05). No obvious correction loss was observed either in coronal or sagittal plane. CONCLUSION: The failure causes of posterior approach orthopaedic operation are hemivertebra processing, selection of fixation and fusion range, and selection of internal fixation. If the strategies of revision are made after the above-mentioned failure causes are considered, the clinical results will be satisfactory.

[Experimental research of antibacterial property and release characteristics of Titania and Ag containing nano-hydroxyapatite/polyamide 66 composite bone filling material in vitro].

OBJECTIVE: Titania and Ag containing nano-hydroxyapatite/polyamide 66 (TiO2-Ag-nHA/PA66) composite bone filling material has good biocompatibility and biological safety. To investigate the antibacterial effect and Ag+ release characteristics of TiO2-Ag-nHA/PA66 composite bone filling material containing different concentrations of Ag+ in vitro. METHODS: The n-HA/PA66 composite bone filling material A1 (material A1) was prepared by co-polymerization method, and TiO2-Ag-nHA/PA66 composite bone filling materials A2 and A3 (materials A2 and A3) were prepared by the same way containing Ag+ of 0.22wt% and 0.64wt%, respectively, and the TiO2 content was 2.35wt%. The materials A2 and A3 were respectively immersed in 50 mL simulated body fluid (SBF), and Ag+ concentration was measured by atomic absorption spectrometry at 1, 3, 7, 14, 21, and 49 days. The inhibition ring test and colony count method were used to evaluate antibiotic effect against Staphylococcus aureus and Escherichia coli, the anti-adhesion capacity of Staphylococcus aureus and Escherichia coli was observed by scanning electron microscope (SEM). RESULTS: There was no significant difference in the Ag+ concentration between materials A2 and A3 at 1 day and 3 days (P > 0.05); and there were significant differences in the Ag+ concentration between materials A2 and A3 after 7 days (P < 0.05). The inhibition ring diameters of materials A2 and A3 to Staphylococcus aureus and Escherichia coli reached the maximum at 1 day, which were (13.40 +/- 2.88), (9.40 +/- 1.14) mm and (23.60 +/- 1.14), (18.80 +/- 0.84) mm, showing significant difference (P < 0.05) between materials A2 and A3 respectively; and then, the diameter of inhibition ring reduced with the time. The antibacterial effect of materials A2 and A3 against Staphylococcus aureus and Escherichia coli lasted 15, 33 days and 9, 24 days, respectively. No inhibition ring was observed around material A1 all the time. And the inhibitory rates of materials A2 and A3 were 89.74% +/- 3.62%, 94.18% +/- 2.05% and 78.65% +/- 5.64%, 85.96% +/- 2.50%; showing significant differences (P < 0.05) among materials A1, A2, and A3. SEM showed that bacterial adhesion of materials A2 and A3 was obviously fewer than that of material A1. CONCLUSION: TiO2-Ag-nHA/PA66 composite bone filling material has antibacterial property against Staphylococcus aureus and Escherichia coli, and it has a good release effect in SBF.

[Establishment and assessment of the mouse model for spinal cord injury].

OBJECTIVE: To make a mouse model of traumatic spinal cord injury (SCI) by Allen's weight dropping (WD), which might be helpful for further research on the mechanism of SCI. METHODS: A total of 180 healthy female mice, weighing 17 - 23 g (20 g on average), were randomized into 4 groups (n=45 per group): the experimental groups of A, B and C and the control group of D. Experimental groups were distinguished by the amount of weight or the height from which the weight was dropped onto an impounded resting on the dura (2.0 x 2.5 g cm, 2.5 x 3.0 g cm, 3.0 x 5.0 g cm). In group D, neural scute was opened only and spinal cord was exposed without SCI. The recovery of the lower extremity was observed at various time points (0, 6 and 12 hours, 1 and 3 days, 1, 2, 4 and 8 weeks) by using the Basso mouse scale (BMS) scoring system, motor evoked potentials (MEP) and histological observation. RESULTS: MEP displayed that the incubation period of N1 wave was extended in group B after 6 hours and in group C after 12 hours. As time passed by, the incubation periods of N1 wave in group A, group B and group C began to shorten. The incubation period in group A was close to normal at 4 weeks (2.40 +/- 0.12) ms, and there was no significant difference compared with group D (P > 0.05). The incubation period in group B was close to normal at 8 weeks (2.96 +/- 0.15) ms, and there was no significant difference compared with group D (P > 0.05). The incubation period in group C was still relatively high at 8 weeks (3.76 +/- 0.13) ms, and there was a significant difference compared with group D (P < 0.05). Both hind limbs of all mice were paralytic instantly after SCI, the score of main BMS was 0 point; the score of main BMS was close to 0 at the first 3 days after SCI, the score of main BMS of group A was 8.00 +/- 0.13 and group B was 7.50 +/- 0.31 at 8 weeks; the score of main BMS of group A was 5.45 +/- 0.12 at 1 week and group B was 5.45 +/- 0.15 at 2 weeks which were significant difference compared with group D (P < 0.05).There were significant differences among groups A, B and C after 1 week of SCI (P < 0.05), and group C was lower than the others(P < 0.01). The score of adjuvant BMS of group A was 10.12 +/- 0.76 at 2 weeks and group B was 9.85 +/- 0.55 at 8 weeks which was no significant difference compared with the group D at the same time (P > 0.05). Histological observation showed hemorrhage, cellular edema, inflammatory cell infiltration, nerve cell swell and solution of Nissl body 12 hours after SCI in group C. As time passed by, the number of nerve cells decreased, the glial cell proliferated and Nissl body vanished. There was much glial cell proliferation and cavitation 2 weeks after SCI in group C. The nerve cell decrease and cavitation in group B was slighter than that in group C, and group A was the slightest. In group D, there was no obvious change of the number of cells during the observation apart from slight edema in early period. CONCLUSION: The mouse model precisely reflects the pathological and physiological features and law of change after different degrees of SCI, and can be used as a standard of mouse model of traumatic SCI by Allen's WD.