Association between periodontitis and disc structural failure in older adults with lumbar degenerative disorders: A prospective cohort study.

BACKGROUND: Bacterial microbiome as a putative trigger of inflammation might indicate the cascade of mouth-gut-disc axis for causing intervertebral disc (IVD) structural failures (such as IVD degeneration and endplate change) processed. However, direct evidence for the mouth-gut-disc axis still unclear. Therefore, it is interesting to explore periodontal inflammation related to IVD structural failures and clinical outcomes. METHODS: This prospective cohort study enrolled older adults (aged ≥ 75 years) who scheduled to undergo elective open lumbar spine surgery. Demographic, radiological, clinical, and periodontal parameters were recorded. Independent samples t-test and Pearson's correlation analysis were calculated. RESULTS: A total of 141 patients with lumbar degenerative disorders (56 males and 85 females; age 79.73 ± 3.34 years) were divided into edentulous group (19 patients), No/Mild group (84 patients), and Moderate/Severe group (38 patients). The incidence rates of IVD degeneration in each lumbar segmental level based on Pfirrmann grade and endplate change in the fourth and fifth lumbar vertebrae, and Visual Analogue Scale (VAS) low back pain (LBP) and leg pain of patients at preoperative in dentate group was significantly higher compared with edentulous group, especially the comparisons between Moderate/Severe and edentulous groups. There were no significant differences in the range of motion, lumbar lordosis, pelvic incidence, pelvic tilt, sacral slope, and disc height between dentate and edentulous groups. There was a positive association between plaque index (PLI) and pain scores (VAS LBP: r = 0.215, P = 0.030 and VAS leg pain: r = 0.309, P = 0.005), but no significant difference in Oswestry disability index (ODI) score. CONCLUSION: Results show that the severity of periodontitis is associated with higher incidence rates of IVD degeneration and endplate change and clinical outcomes in older adults with lumbar degenerative disorders. Furthermore, the discovery of these relationships unveils a novel mechanism through which the alterations in oral microbiome composition potentially promote IVD degeneration and pain.

Construction of a Polypyrrole-Based Multifunctional Nanocomposite for Dual-Modal Imaging and Enhanced Synergistic Phototherapy against Cancer Cells.

Design and construction of multifunctional theranostic nanoplatforms are still desired for cancer-effective treatment. Herein, a kind of polypyrrole (PPy)-based multifunctional nanocomposite was designed and successfully constructed for dual-model imaging and enhanced synergistic phototherapy against cancer cells. Through graphene oxide (GO) sheet coating, PPy nanoparticles (NPs) were effectively combined with polyethylene glycol chains, Au NPs, and IR820 molecules. The obtained PGPAI NPs showed promising ability for photoacoustic/computed tomography imaging. Under near-infrared light irradiation, the PPy core and IR820 molecule effectively generated heat and reactive oxygen species (ROS), respectively. Furthermore, the loaded Au NPs owning catalase-like activity produced oxygen by decomposing H2O2 (up-regulated in tumor region), enhancing the oxygen-dependent photodynamic therapy efficacy. The formed PGPAI NPs were also proved to own desirable photothermal conversion efficiency, photothermal stability, colloidal stability, cytocompatibility, and cellular internalization behaviors. Furthermore, cell assay demonstrated that PGPAI NPs displayed enhanced synergistic phototherapy efficacy against cancer cells. These developed multifunctional nanoplatforms are promising for effective cancer theranostic applications.

Enhanced Photoacoustic and Photothermal Effect of Functionalized Polypyrrole Nanoparticles for Near-Infrared Theranostic Treatment of Tumor.

Functionalized nanomaterials with near-infrared (NIR) responsive capacity are quite promising for theranostic treatment of tumors, but formation of NIR responsive nanomaterials with enhanced theranostic ability and excellent biocompatibility is still very challenging. Herein, PEGylated indocyanine green (ICG)-loaded polypyrrole nanoparticles (PPI NPs) were designed and successfully formed through selecting polydopamine as the linkage between each component, demonstrating enhanced NIR responsive theranostic ability against tumor. By combining in vitro cell study with in vivo assay, the formed PPI NPs were proven to be fantastically biocompatible while effectively internalization in HeLa cells and retention in HeLa tumor were demonstrated by in vitro flow cytometry/confocal measurement and in vivo photoacoustic imaging assay. With the guidance of photoacoustic imaging, successful photothermal ablation of tumor was achieved by treatment with PPI NPs plus laser, which was much more effective than the group treated with NPs free of ICG. The combined enhanced photoacoustic and photothermal effect is mainly ascribed to the functionalized polypyrrole nanoparticles, which could accumulate in the tumor site more effectively with a relatively longer retention time taking advantage of the nanomaterial-induced endothelial leakiness phenomenon. All these results demonstrating that this designed PPI NPs possessing enhanced NIR responsive property hold great promise for tumor NIR theranostic applications.

Basic research and clinical applications of bisphosphonates in bone disease: what have we learned over the last 40 years?

It is now 40 years since bisphosphonates (BPs) were first used in the clinic. So, it is timely to provide a brief review of what we have learned about these agents in bone disease. BPs are bone-specific and have been classified into two major groups on the basis of their distinct molecular modes of action: amino-BPs and non-amino-BPs. The amino-BPs are more potent and they inhibit farnesyl pyrophosphate synthase (FPPS), a key enzyme of the mavalonate/cholesterol biosynthetic pathway, while the non-amino-BPs inhibit osteoclast activity, by incorporation into non-hydrolyzable analogs of ATP. Both amino-BPs and non-amino-BPs can protect osteoblasts and osteocytes against apoptosis. The BPs are widely used in the clinic to treat various diseases characterized by excessive bone resorption, including osteoporosis, myeloma, bone metastasis, Legg-Perthes disease, malignant hyperparathyroidism, and other conditions featuring bone fragility. This review provides insights into some of the adverse effects of BPs, such as gastric irritation, osteonecrosis of the jaw, atypical femoral fractures, esophageal cancer, atrial fibrillation, and ocular inflammation. In conclusion, this review covers the biochemical and molecular mechanisms of action of BPs in bone, particularly the discovery that BPs have direct anti-apoptotic effects on osteoblasts and osteocytes, and the current situation of BP use in the clinic.

Biomimetic Design and Fabrication of Sericin-Hydroxyapatite Based Membranes With Osteogenic Activity for Periodontal Tissue Regeneration.

The guided tissue regeneration (GTR) technique is a promising treatment for periodontal tissue defects. GTR membranes build a mechanical barrier to control the ingrowth of the gingival epithelium and provide appropriate space for the regeneration of periodontal tissues, particularly alveolar bone. However, the existing GTR membranes only serve as barriers and lack the biological activity to induce alveolar bone regeneration. In this study, sericin-hydroxyapatite (Ser-HAP) composite nanomaterials were fabricated using a biomimetic mineralization method with sericin as an organic template. The mineralized Ser-HAP showed excellent biocompatibility and promoted the osteogenic differentiation of human periodontal membrane stem cells (hPDLSCs). Ser-HAP was combined with PVA using the freeze/thaw method to form PVA/Ser-HAP membranes. Further studies confirmed that PVA/Ser-HAP membranes do not affect the viability of hPDLSCs. Moreover, alkaline phosphatase (ALP) staining, alizarin red staining (ARS), and RT-qPCR detection revealed that PVA/Ser-HAP membranes induce the osteogenic differentiation of hPDLSCs by activating the expression of osteoblast-related genes, including ALP, Runx2, OCN, and OPN. The unique GTR membrane based on Ser-HAP induces the differentiation of hPDLSCs into osteoblasts without additional inducers, demonstrating the excellent potential for periodontal regeneration therapy.

Accuracy evaluation of partially guided and fully guided templates applied to implant surgery of anterior teeth: A randomized controlled trial.

OBJECTIVES: To study the accuracy of partially guided and fully guided templates applied to implant surgery of anterior teeth. MATERIALS AND METHODS: Sixty patients who were scheduled to receive dental implant treatment in the anterior region were enrolled and randomly assigned to one of the following study groups (n = 20 each): routine implant-supported restoration treatment (control group, 30 implants), implant-supported restoration treatment using a partially guided template (test group 1, 36 implants), and implant-supported restoration treatment using a fully guided template (test group 2, 33 implants). The depth of implant was controlled for fully guided template. After implantation, planned implants and placed implants were superimposed using digital software, and the deviations (angular, coronal, apical, depth) were analyzed. Esthetic parameters were assessed at baseline, 6 months, and 1 year after the final restoration. Pink esthetic score (PES) and white esthetic score (WES) were respectively used to evaluate the soft tissue and restoration esthetic outcome. Each parameter of PES and WES is assessed with a 0-1-2 score with 2 being the best and 0 being the worst score. RESULTS: There were significant differences in all of the deviation parameters between the control group, test group 1, and test group 2 (p < 0.001). Mean angular, coronal, apical and depth deviations were all the highest in the control group (6.61 ± 1.09°, 1.05 ± 0.17 mm, 1.36 ± 0.13 mm, and 1.02 ± 0.13 mm, respectively), and lowest in test group 2 (2.05 ± 0.45°, 0.39 ± 0.12 mm, 0.28 ± 0.09 mm, and 0.24 ± 0.06 mm, respectively). At 1 year after the final restoration, the analysis revealed mean PES values of 7.09 ± 0.56 (control group), 8.39 ± 0.54 (test group 1), and 9.04 ± 0.35 (test group 2). The WES values were 7.24 ± 0.54 (control group), 8.47 ± 0.44 (test group 1), and 8.97 ± 0.38 (test group 2). At all examinations, the mean PES and WES values were both the highest in test group 2 and lowest in the control group. The PES and WES values recorded in the control group at baseline, 6 months, and 1 year after final restoration were significantly lower than those in test groups (p < 0.001). Moreover, the PES and WES values recorded in the test group 1 at baseline, 6 months, and 1 year after final restoration were significantly lower than those in test group 2 (p < 0.05). CONCLUSIONS: Digital surgical guides can improve the accuracy of the three-dimensional position of implants in the maxillary esthetic zone, the fully guided template has higher precision than that of the partially guided template, and plays an important role in obtaining the ideal esthetic outcome for maxillary anterior teeth.

Integration of cascade delivery and tumor hypoxia modulating capacities in core-releasable satellite nanovehicles to enhance tumor chemotherapy.

Drug nanovehicles owning tumor microenvironment responsive and modulating capacities are highly demanding for effective tumor chemotherapy but still lack of exploration. Here, a kind of core-releasable satellite nanovehicles was rational constructed, which is composed of polydopamine (PDA) cores as photothermal agents and the carrier for small satellite nanoparticles (NPs) and drugs, G5Au NPs as the drug-loading satellites for deep tumor drug delivery and as catalase-like agents for relieving tumor hypoxia, doxorubicin (DOX) as the model chemotherapeutic drug loaded by both PDA and G5Au NPs, and polyethylene glycol (PEG) shells to improve biosafety. The developed drug-loaded nanovehicles (denoted as PDA-G5Au-PEG@DOX) can release G5Au satellites and DOX in stimuli-responsive manners. Thorough drug delivery in solid tumor can be realized via transporting DOX to the near-by area of and remote area from blood vessels by PDA and G5Au, respectively. Monitored by photoacoustic imaging and near-infrared fluorescence imaging, these PDA-G5Au-PEG@DOX NPs could accumulate in 4T1 tumor effectively. Under this guidance, significant tumor growth suppression could be achieved by the treatment of PDA-G5Au-PEG@DOX NPs plus laser without detectable side effects during the treatment period. The developed drug-loaded core-satellite nanovehicles with tumor microenvironment responsive/modulating capacities are of great potential in precise tumor treatments.

[Fabrication and characteristics of oriental poly (lactic-co-glycolic acid) scaffold: a preliminary study].

OBJECTIVE: To explore the method of fabricating oriental scaffolds and investigate the biocompatibility of the scaffolds as well as cells distribution within the scaffolds in vitro. METHODS: The oriental poly (lactic-co-glycolic acid) (PLGA) scaffolds were fabricated with modified emulsion-phase separation method. The scaffolds were treated with plasma and then anchored with collagen I. Articular chondrocytes were loaded into the scaffolds. The growth status and distributing characteristic of the cells were investigated by environmental scanning electron microscope. RESULTS: The scaffold was well compatible with the articular chondrocytes. The cells could reach to 2.5 mm depth with unilateral loading. The cells distributed evenly in the scaffold and lined along the inner pipes. CONCLUSIONS: The oriental scaffold fabricated could significantly promote the distributing characteristics of the chondrocytes. The vertical alignment of the chondrocytes within the scaffold is closely similar to that of articular cartilage.

Methylated genomic loci encoding microRNA as a biomarker panel in tissue and saliva for head and neck squamous cell carcinoma.

Background: To identify aberrant promoter methylation of genomic loci encoding microRNA (mgmiR) in head and neck squamous cell carcinoma (HNSCC) and to evaluate a biomarker panel of mgmiRs to improve the diagnostic accuracy of HNSCC in tissues and saliva. Methods: Methylation of promoter regions of mgmiR candidates was initially screened using HNSCC and control cell lines and further selected using HNSCC and control tissues by quantitative methylation-specific PCR (qMS-PCR). We then examined a panel of seven mgmiRs for validation in an expanded cohort including 189 HNSCC and 92 non-HNSCC controls. Saliva from 86 pre-treatment HNSCC patients and 108 non-HNSCC controls was also examined using this panel of seven mgmiRs to assess the potentials of clinical utilization. Results: Among the 315 screened mgmiRs, 12 mgmiRs were significantly increased in HNSCC cell lines compared to control cell lines. Seven out of the 12 mgmiRs, i.e., mgmiR9-1, mgmiR124-1, mgmiR124-2, mgmiR124-3, mgmiR129-2, mgmiR137, and mgmiR148a, were further found to significantly increase in HNSCC tumor tissues compared to control tissues. Using multivariable logistic regression with dichotomized variables, a combination of the seven mgmiRs had sensitivity and specificity of 92.6 and 92.4% in tissues and 76.7 and 86.1% in saliva, respectively. Area under the receiver operating curve for this panel was 0.97 in tissue and 0.93 in saliva. This model was validated by independent bootstrap validation and random forest analysis. Conclusions: mgmiR biomarkers represent a novel and promising screening tool, and the seven-mgmiR panel is able to robustly detect HNSCC in both patient tissue and saliva.

Draft Genome Sequence of Oral Bacterium Streptococcus mutans JH1140.

Streptococcus mutans JH1140 is an oral bacterium known to produce the bacteriocin mutacin 1140, and the strain has been genetically engineered to combat dental caries. Here, we report the 2.0-Mb draft genome of S. mutans JH1140. This genome provides new insights into the strain's superior colonization properties and its utility in replacement therapy.

Use of electrospinning to construct biomaterials for peripheral nerve regeneration.

A number of limitations associated with the use of hollow nerve guidance conduits (NGCs) require further discussion. Most importantly, the functional recovery outcomes after the placement of hollow NGCs are poor even after the successful bridging of peripheral nerve injuries. However, nerve regeneration scaffolds built using electric spinning have several advantages that may improve functional recovery. Thus, the present study summarizes recent developments in this area, including the key cells that are combined with the scaffold and associated with nerve regeneration, the structure and configuration of the electrospinning design (which determines the performance of the electrospinning scaffold), the materials the electrospinning fibers are composed of, and the methods used to control the morphology of a single fiber. Additionally, this study also discusses the processes underlying peripheral nerve regeneration. The primary goals of the present review were to evaluate and consolidate the findings of studies that used scaffolding biomaterials built by electrospinning used for peripheral nerve regeneration support. It is amazing that the field of peripheral nerve regeneration continues to consistently produce such a wide variety of innovative techniques and novel types of equipment, because the introduction of every new process creates an opportunity for advances in materials for nerve repair.

[The preparation, structure evaluation and preliminary application of biomimetic biphasic calcium phosphate scaffold].

OBJECTIVE: To fabricate biomimetic biphasic calcium phosphate BCP ceramic scaffolds using three-dimensional (3D) gel-lamination technology and evaluated their structure with 3D parameters and related method. METHODS: Series two-dimensional images of femoral head's specimen of dogs were obtained by micro-computed tomography (Micro-CT). According to these images, porous biomimetic biphasic calcium phosphate (BCP) ceramic scaffolds with oriented trabecular structure were fabricated by three-dimensional (3D) gel-lamination technology. And then, the three-dimensional structure of the scaffolds were reconstructed by computer according to Micro-CT images of these scaffolds and evaluated by three-dimensional parameters. These parameters included bone volume fraction (BVF, BV/TV), bone surface/bone volume (BS/BV) ratio, trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular spacing (Tb.Sp) and structure model index (SMI). The biomechanical properties and biocompatibility of these scaffolds were also evaluated in the study. Six scaffolds, which were combined with BMCs (bone mesenchymal cells, BMCs), were planted into the bone defect of six dogs' femoral head respectively. RESULTS: There was no significant difference between trabecular samples and BCP scaffolds in BV/TV, Tb.Th, Tb.N, and Tb.Pf (P > 0.05). The trabecular system of the scaffold, which had some orientation, represented plate-like model. With a micro-porous porosity of 62%, the average compressive modulus and ultimate strength along the axis of the scaffolds reached (464.0 +/- 36.0) MPa and (5.6 +/- 0.8) MPa respectively. The results of animal test indicated that the trabeculae of these scaffolds were covered by a layer of new bone after 10 weeks of operation. CONCLUSION: Porous BCP scaffolds have been produced with oriented microarchitectural features designed to facilitate vascular invasion and cellular attachment and with initial mechanical properties comparable to those of trabecular bone.

[The position and application of nanotechnology in the development of life science].

In this article, the position of nanotechnology and its effects on life science are concisely discussed, including the effects of nanotechnology on biology, on the study of new type biomaterials, on the development of new drugs, on diagnosis and therapy methods. The importance of nanotechnology in life science is summarized, and the application and development of nanotechnology in life science are also discussed.

[The CXC-chemokine platelet factor 4 (PF4) increases KG1a cells adherence and modulates actin polymerization of KG1a cells].

OBJECTIVE: To study the effects on adherence of hematopoietic stem/progenitor cells, PF4 was assessed alone or in combination with IL-3 for effects on the total adherence and various kinds of adhesion molecules of KG1a cells as well as actin polymerization in KG1a cells. METHODS: The total adherence was assayed by crystal violet dye staining. The adhesion molecule expression was determined by FACS analysis. These adhesion molecule monoclonal antibodies individually blocked total adherence by MTT. F-actin content was monitored by fluorospectrophotometry. RESULTS: 100 ng/ml PF4 could increase the total adherence of KG1a cells by 80%. 20 ng/ml IL-3 could increase the total adherence of KG1a cells by 96%. When PF4 and IL-3 were combined, the total adherence could be promoted by 97%. Exposure of 1 x 10(6) cells/ml of KG1a cells to 100 ng/ml PF4 the increased total adherence of KG1a cells was mediated by PECAM-1 (CD31), CD44, LFA-1 (CD11a) and Mac-1 (CD11b) but not by P-selectin (CD62P) and E-selectin (CD62E). These adhesion molecule monoclonal antibodies could individually block total adherence for 34%-43%. Similar phenomenon was observed when IL-3 was added onto KG1a cells. Further study found that PF4 induced actin polymerization of KG1a cells. CONCLUSIONS: Our study indicated that PF4 promoted total adherence, as well as several adhesion molecule expression and actin polymerization of KG1a cells. The results suggest that PF4 may have therapeutic utility along with other cytokines by enhancing the total adhesion of hematopoietic stem/progenitor cells to promote the homing.

[Acellular nerve allograft by chemical extraction in humans].

OBJECTIVE: To develop a procedure by which Schwann cells and myelin in the peripheral nerve could be removed while the basal lamina tubes remained intact, and to obtain a thick and long acellular nerve allograft in humans. METHODS: Four ulnar nerves 10.0 cm long and 4.0 - 5.0 mm in diameter were excised from a donated male body and cleaned from external debris. The nerves were treated with a solution of Triton X-100 and a solution of sodium deoxycholate at room temperature. After a final wash in water, the nerves were stored in phosphate-buffered saline (PBS, pH 7.2) at 4 degrees C. HE, luxol fast blue and fibrin staining were performed to visualize cells, myelin and basal membranes respectively and immunohistochemical staining was performed to visualize the presence of laminin, a Schwann cell lamina component, both in fresh and acellular nerve segments. To reveal overall structure better, methylene blue-fuchsin staining was performed in semithin section. The ultrastructure of acellular and fresh nerves were observed and photographed in a transmission electron microscope. RESULTS: The acellular human ulnar nerve was white long cylinder with well elasticity and ductility. HE, myelin and fibrin staining revealed that cells, axons and myelin sheath were removed and basal membrane was preserved after extraction procedure. Staining for the presence of laminin showed that the Schwann cell basal lamina component were present in the nerves after chemical treatment. Methylene blue-fuchsin staining and transmission electron microscopy showed that the myelin sheaths were absent in the extracted nerve segments and empty basal lamina tubes remained in the endoneurium. CONCLUSIONS: We developed an extracted procedure with the detergents of Triton X-100 and deoxycholate, by which cells, axons and myelin sheaths could be removed from a human ulnar nerve while the basal lamina tubes remain intact and a thick long acellular nerve allograft is obtained. The laminin, a Schwann cell basal lamina component, can be preserved in the acellular nerve.

[A comparative study of Bolton index in the youth and middle-aged and elderly people].

PURPOSE: To Investigate the changes of Bolton index, maxillary and mandibular teeth size and teeth size discrepancy (TSD) in the youth and middle- aged and elderly people. METHODS: One hundred ninety-one youth dental plaster casts from malocclusion patients and 63 middle-aged and elderly people with snoring or obstructive sleep apnea-hypopnea syndrome (OSAHS) patients were selected. 12 teeth size between the upper and lower first molar, width of maxillary lateral incisor, Bolton anterior and overall ratios and teeth size discrepancy were measured and calculated. Statistical analysis was performed using SPSS 13.0 software package. RESULTS: There was no significant difference between the 2 groups in Bolton anterior and overall ratios (P<0.05 ).The mean size of the upper lateral tooth in the youth was larger than the middle-aged and elderly people(P<0.01).There was no significant difference in 6 upper or lower anterior teeth size between canine and 12 mandibular teeth size between first molar in 2 groups, but the mean teeth size in the middle-aged and elderly people was smaller.The prevalence of anterior and overall TSD in the youth was 31.4% and 42.4%,while it was 19.05% and 15.9% in the middle-aged and elderly group. There was significant difference(P<0.05) between 2 groups in width of upper lateral incisor, which was 7.46mm in the youth and 7.20 mm in the middle-aged and elderly group. Prevalence of laminal width of upper lateral incisor in patients with teeth size discrepancy was low. CONCLUSIONS: Bolton index does not change by age. Although the teeth size in middle-aged and elderly group are smaller than the youth group, the total reduction is little without clinical significance. The laminal width of upper lateral incisor isn't the main cause for anterior or overall dental size discrepancy. Supported by Research Fund from Department of Public Health of Guangxi Zhuang Autonomous Region (GWZ2013405 and GWZ2007149).

[Effect of controlled release fertilizer on nitrous oxide emission from paddy field under plastic film mulching cultivation].

A field experiment was conducted to assess the effect of controlled release fertilizer on N2O emission in paddy field under plastic film mulching cultivation (PM) with water-saving irrigation. Results showed that in the rice growing season, cumulative N2O emissions from the plots applied with urea (PM+U) and with controlled release fertilizer (PM+CRF) were (38.2 +/- 4.4) and (21.5 +/- 5.2) mg N x m(-2), respectively. The N2O emission factors were 0.25% and 0.14% in the treatments PM+U and PM+CRF, respectively. The controlled release fertilizer decreased the total N2O emission by 43.6% compared with urea, of which 49.6% was reduced before the drying period. It also reduced the peak of N2O emission by 52.6%. However, it did not affect soil microbial biomass N and soil NH(4+)-N content at any rice growing stage, and grain yield either. No significant correlation was observed between N2O flux and soil Eh or soil temperature at the depth of 5 cm.

Bone cement enhanced pedicle screw fixation combined with vertebroplasty for elderly patients with malignant spinal tumors.

BACKGROUND: Older patients with malignant spinal tumors are difficult to treat because they have many co-morbidities including osteoporosis. The purpose of this research is to discuss the technique and clinical outcome of bone cement enhanced pedicle screw fixation combined with vertebroplasty (the Sandwich Procedure) for elderly patients with severe osteoporosis and malignant spinal tumors. METHODS: This study includes 28 consecutive elderly patients with malignant thoracic or lumbar spinal tumors. There were nine patients with myelomas, and 19 patients with metastatic bone tumors. The Sandwich Procedure began with curettage of the tumor and a vertebroplasty with bone cement (polymethyl methacrylate, PMMA), followed by PMMA enhanced pedicle screw fixation. Patients were evaluated with the visual analogue scale (VAS), oswestry disability index (ODI), American Spinal Cord Injury Association (ASIA) neurological function classification, and the radiographic degree of kyphosis (Cobb angle). Data were analyzed using paired t-test to compare the pre- and post-operative values. The complications, local recurrences, and the survival status were also recorded. RESULTS: There was no operative mortality, and the mean operative time was 210 minutes (range 150 - 250 minutes). The average blood loss was 1550 ml (range 650 - 3300 ml). The average amount of cement for vertebroplasty was 3.6 ml (range 3 -5 ml). The VAS, ODI, and ASIA scores were significantly improved after surgery (P < 0.05). However, we found no differences between the pre and post-operative Cobb angles. The shortest survival time was 3 months, and we found no evidence of local recurrence in this group of patients. CONCLUSION: The Sandwich Procedure is a safe operation and provides symptomatic relief in these difficult patients, permitting further treatment with chemotherapy or radiotherapy.

Biocompatibility evaluation of electrospun aligned poly (propylene carbonate) nanofibrous scaffolds with peripheral nerve tissues and cells in vitro.

BACKGROUND: Peripheral nerve regeneration across large gaps is clinically challenging. Scaffold design plays a pivotal role in nerve tissue engineering. Recently, nanofibrous scaffolds have proven a suitable environment for cell attachment and proliferation due to similarities of their physical properties to natural extracellular matrix. Poly(propylene carbonate) (PPC) nanofibrous scaffolds have been investigated for vascular tissue engineering. However, no reports exist of PPC nanofibrous scaffolds for nerve tissue engineering. This study aimed to evaluate the potential role of aligned and random PPC nanofibrous scaffolds as substrates for peripheral nerve tissue and cells in nerve tissue engineering. METHODS: Aligned and random PPC nanofibrous scaffolds were fabricated by electrospinning and their chemical characterization were carried out using scanning electron microscopy (SEM). Dorsal root ganglia (DRG) from Sprague-Dawley rats were cultured on the nanofibrous substrates for 7 days. Neurite outgrowth and Schwann-cell migration from DRG were observed and quantified using immunocytochemistry and SEM. Schwann cells derived from rat sciatic nerves were cultured in electrospun PPC scaffold-extract fluid for 24, 48, 72 hours and 7 days. The viability of Schwann cells was evaluated by 3-[4,5-dimethyl(thiazol-2-yl)-2,5-diphenyl] tetrazolium bromide (MTT) assay. RESULTS: The diameter of aligned and random fibers ranged between 800 nm and 1200 nm, and the thickness of the films was approximately 10 - 20 µm. Quantification of aligned fiber films revealed approximately 90% alignment of all fibers along the longitudinal axis. However, with random fiber films, the alignment of fibers was random through all angle bins. Rat DRG explants were grown on PPC nanofiber films for up to 1 week. On the aligned fiber films, the majority of neurite outgrowth and Schwann cell migration from the DRG extended unidirectionally, parallel to the aligned fibers. However, on the random fiber films, neurite outgrowth and Schwann cell migration were randomly distributed. A comparison of cumulative neurite lengths from cultured DRGs indicated that neurites grew faster on aligned PPC films ((2537.6 ± 987.3) µm) than randomly-distributed fibers ((493.5 ± 50.6) µm). The average distance of Schwann cell migration on aligned PPC nanofibrous films ((2803.5 ± 943.6) µm) were significantly greater than those on random fibers ((625.3 ± 47.8) µm). The viability of Schwann cells cultured in aligned PPC scaffold extract fluid was not significantly different from that in the plain DMEM/F12 medium at all time points after seeding. CONCLUSIONS: The aligned PPC nanofibrous film, but not the randomly-oriented fibers, significantly enhanced peripheral nerve regeneration in vitro, indicating the substantial role of topographical cues in stimulating endogenous nerve repair mechanisms. Aligned PPC nanofibrous scaffolds may be a promising biomaterial for nerve regeneration.