Min-invasive surgical treatment for multiple axis fractures: A case report

BACKGROUND

Fractures of the axis are commonly seen in spinal injuries. Upper cervical fractures are usually managed conservatively. However, the complications due to long-term external immobilization cannot be ignored. The traditional open surgery has the disadvantages of too much blood loss and soft tissue injury. The aim of our paper is to introduce a minimally invasive surgical treatment for multiple axis fractures.

CASE SUMMARY

We report a 40-year-old Chinese male who had severe neck pain and difficult neck movement after falling from 3 meters. X-ray and computed tomography (CT) scan revealed an axis injury consisting of an odontoid Type III fracture associated with a Hangman fracture categorized as a Levine-Edwards Type I fracture. The patient underwent anterior odontoid screw fixation and posterior percutaneous screw fixation using intraoperative O-arm navigation. Neck pain was markedly improved after surgery. X-rays and CT scan reconstructions of 3-mo follow-up showed good stability and fusion. The range of cervical motion was well preserved.

CONCLUSION

Anterior odontoid screw fixation and posterior direct C2 percutaneous pedicle screw fixation with the aid of O-arm navigation and neurophysiological monitoring can be an interesting alternative option for complicated multiple axis fractures.

[Expressions and prognostic significance of PTEN and PD-1 protein in patients with classical Hodgkin's lymphoma]

目的

分析肿瘤免疫耐受信号通路的重要因子PD-1和PTEN在经典型霍奇金淋巴瘤（CHL）患者中的表达及其与患者临床特征和预后的相关性。

方法

回顾性分析2003年2月至2013年8月诊治的56例CHL患者的临床资料。采用免疫组织化学染色法检测CHL患者PD-1和PTEN蛋白的表达，采用原位杂交法检测EBV及EBV编码的小mRNA（EBER），并结合患者的临床特征与生存状态进行相关性分析。

结果

①56例患者中，男34例，女22例，中位年龄25（7~71）岁，PTEN阳性者11例（19.64%），PD-1阳性者14例（25.00%）。②PTEN和PD-1表达呈正相关（rs=0.320，P=0.016）；PTEN表达与Ann Arbor分期、IPS评分和有无大包块（≥5 cm）明显相关，PD-1仅与有无大包块相关（P值均<0.05）。③中位随访43（5~86）个月，多因素分析结果显示：年龄≥45岁（P<0.001）、IPS评分>2分（P=0.026）、EBER阳性（P=0.004）、PTEN蛋白高表达（P=0.035）是影响患者5年总生存的不良预后因素，也是影响5年无进展生存的不良预后因素（P值分别为0.007、0.014、0.002、0.024）。

结论

肿瘤免疫逃逸信号通路因子PTEN与CHL患者的预后相关，对CHL患者的预后判断有一定作用，同时也为CHL的免疫治疗提供了新思路和理论依据。

Recycling and reuse of kerf-loss silicon from diamond wire sawing for photovoltaic industry

With the rapid growth of the global photovoltaic (PV) industry, the waste from PV industry cannot be ignored, especially the solid wastes from silicon kerf loss and the used quartz crucibles from silicon casting. The silicon kerf loss during wafer sawing was nearly 160,000 tonnes and the used crucible waste was nearly 70,000 tonnes in 2017. With the transition of wafering technology from the slurry-based wire to diamond wire sawing, recycling and reuse of kerf-loss silicon have become more feasible due to the lower impurity contents. In this paper, we aimed to find a simple approach to recycle the kerf loss and identify the purity for reuse. We first analyzed the contents of the as-received kerf-loss silicon from the industry. Then, suitable acids and refining procedure were proposed. The metals, especially nickel, could be easily reduced to several ppmw, boron and phosphorous to sub-ppmw, and carbon to several hundred ppmw, while oxygen was less than 5 wt%. Although the purity of the recycled silicon was not sufficient for casting feedstock, it had a comparable purity of about 5 N with the commercial silicon nitride releasing agent and crucibles used in silicon casting for solar cells. Because the nitride crucibles could be reused a few times for casting, the used crucible waste could be significantly reduced as well.

Nano and micro biomechanical alterations of annulus fibrosus after in situ immobilization revealed by atomic force microscopy

Annulus fibrosus is critical to bear loads and resist fluid flow in the intervertebral disc. However, the detailed biomechanical mechanism of annulus fibrosus under abnormal loading is still ambiguous, especially at the micro and nano scales. This study aims to characterize the alterations of modulus at the nano scale of individual collagen fibrils in annulus fibrosus after in-situ immobilization, and the corresponding micro-biomechanics of annulus fibrosus. An immobilization model was used on the rat tail with an external fixation device. The elastic modulus of annulus fibrosus at both the nano- and micro-scale was examined using atomic force microscopy after fixation for 4 and 8 weeks, respectively. The fibrils in inner layer showed an alteration in elastic modulus from 91.38 ± 20.19 MPa in the intact annulus fibrosus to 110.64 ± 15.58 MPa (p < 0.001) at the nano scale after immobilization for 8 weeks, while the corresponding modulus at the micro scale also underwent a change from 0.33 ± 0.04 MPa to 0.47 ± 0.04 MPa (p < 0.001). The fibril disorder after immobilization was observed by hematoxylin/eosin staining. The gene expression of annulus fibrosus was also measured by real-time reverse transcription-polymerase chain reaction, which showed the upregulation of collagen II (p = 0.003) after immobilization. The results indicated that the immobilization not only influenced the individual fibril at the nanoscale, but also the micro-biomechanical property of annulus fibrosus which is critical to define the cell response to surrounding biomechanical environment. These alterations may also lead to the change in the mechanical property of the whole disc and the load-bearing function. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-7, 2018.

Mid- to long-term results of total disc replacement for lumbar degenerative disc disease: a systematic review

Background

Lumbar total disc replacement (TDR) has shown satisfactory clinical outcomes with few complications and reoperations at short-term follow-up, but the mid- to long-term results are not clear.

Purpose

The objective of this study was to evaluate the mid- to long-term clinical outcomes of artificial TDR for lumbar degenerative disc diseases.

Patients and methods

A systematic search was conducted using the PubMed database to identify studies of TDR surgery that included at least 3 years of follow-up. The search keywords were as follows: lumbar, total disc replacement, and arthroplasty. The following data were extracted: patient demographics, visual analogue scale (VAS) and Oswestry disability index (ODI) scores, satisfactory rate, clinical success rate, complications, and reoperations.

Results

Thirteen studies, including eight prospective studies and five retrospective studies, met the criteria. A total of 946 patients were identified who reported at least 3 years of follow-up results. The artificial prostheses in these studies were ProDisc-L, Charité, AcroFlex, Maverick, and XL TDR. Patients with lumbar TDR demonstrated significant improvements in VAS scores of 51.1 to 70.5% and of − 15.6 to − 44.4 for Oswestry disability index (ODI) scores at the last follow-up. Patient satisfaction rates were reported in eight studies and ranged from 75.5 to 93.3%. Complication rates were reported in 11 studies, ranging from 0 to 34.4%. The overall reoperation rate was 12.1% (119/986), ranging from 0 to 39.3%, with eight of the 13 studies reporting a reoperation rate of less than 10%.

Conclusions

This review shows that lumbar TDR effectively results in pain relief and an improvement in quality of life at mid- to long-term follow-up. Complication and reoperation rates were acceptable. However, this study did not provide sufficient evidence to show that lumbar TDR is superior to fusion surgery. To answer that question, a greater number of high-quality randomized controlled trials (RCTs) are needed.

Intervertebral disc degeneration induced by long-segment in-situ immobilization: a macro, micro, and nanoscale analysis

Background

Cervical spine fixation or immobilization has become a routine treatment for spinal fracture, dislocation, subluxation injuries, or spondylosis. The effects of immobilization of intervertebral discs of the cervical spine is unclear. The goal of this study was to evaluate the effects of long-segment in-situ immobilization of intervertebral discs of the caudal vertebra, thereby simulating human cervical spine immobilization.

Methods

Thirty-five fully grown, male Sprague-Dawley rats were used. Rats were randomly assigned to one of five groups: Group A, which served as controls, and Groups B, C, D, and E, in which the caudal vertebrae were in-situ immobilized using a custom-made external device that fixed four caudal vertebrae (Co7-Co10). After 2 weeks, 4 weeks, 6 weeks, and 8 weeks of in-situ immobilization, the caudal vertebrae were harvested, and the disc height, the T2 signal intensity of the discs, disc morphology, the gene expression of discs, and the structure and the elastic modulus of discs was measured.

Results

The intervertebral disc height progressively decreased, starting at the 6th week. At week 6 and week 8, disc degeneration was classified as grade III, according to the modified Pfirrmann grading system criteria. Long-segment immobilization altered the gene expression of discs. The nucleus pulposus showed a typical cell cluster phenomenon over time. The annulus fibrosus inner layer began to appear disordered with fissure formation. The elastic modulus of collagen fibrils within the nucleus pulposus was significantly decreased in rats in group E compared to rats in group A (p < 0.05). On the contrary, the elastic modulus within the annulus was significantly increased in rats in group E compared to rats in group A (p < 0.05).

Conclusion

Long-segment in-situ immobilization caused target disc degeneration, and positively correlated with fixation time. The degeneration was not only associated with changes at the macroscale and microscale, but also indicated changes in collagen fibrils at the nanoscale. Long-segment immobilization of the spine (cervical spine) does not seem to be an innocuous strategy for the treatment of spine-related diseases and may be a predisposing factor in the development of the symptomatic spine.

Effect of Static Compression Loads on Intervertebral Disc: An in Vivo Bent Rat Tail Model

OBJECTIVE

To evaluate how well different magnitudes of compression-induced degenerative changes using a bent rat tail model simulated human lumbar lordosis. It has been shown that compression plays an important role in intervertebral disc degeneration (IDD).

METHODS

Sprague-Dawley rats (n = 25) were instrumented with a special compressive apparatus that was used to bend the intervertebral disc between the 8th and the 10th caudal vertebral bodies using two Kirschner wires inserted percutaneously into the middle of two tail vertebrae. Then, rats were divided into five different static compression loads (control, sham, 1.8 N, 4.5 N, and 7.2 N). The degeneration of the discs was evaluated by magnetic resonance imaging (MRI), histology, gene expression of anabolism and catabolism after 2 weeks. We used the signal characteristics of the disc in T2-weighted MRI to reflect the changes caused by degeneration as this is the most relevant and clinically recognized way to assess IDD. Pfirrmann classification was used to classify disc images. The tail discs from C_8-9 and C_9-10 with their two adjacent half vertebrae were carefully cut out and decalcified. Then the sections were paraffin-embedded and cut into 5-μm sections by histotome. Finally, they were stained with Safranin O-Fast Green and hematoxylin, and hematoxylin and eosin, respectively. Images were taken using a microscope and staining and compression-induced changes were assessed by a Masuda's grading scale. The relative expression levels of mRNA encoding rat anabolic genes and catabolic genes were evaluated by real-time reverse transcription (RT)-polymerase chain reaction (PCR). The mRNA expression fold change of the target gene was calculated using the 2^-ΔΔCt method in the loaded and unloaded disc.

RESULTS

As the loading magnitude increased, static compression produced a significantly progressive decrease in nucleus intensity on T2-weighted MRI, a decrease of aggrecan and Type II collagen, an increase in Matrix metallopeptidase-3 (MMP-3) and MMP-13 expressions, and a histomorphological degeneration. The sham group had a score of 1.4 ± 0.3, the 1.8 N group had a score of 2.4 ± 0.3, the 4.5 N group had a score of 3.2 ± 0.3, and the 7.2 N group had a score of 4.4 ± 0.3, which was based on the Pfirrmann classification score, in which the control group had a score of 1. These results demonstrated that the sham group was not significantly different from the control group. Histological analysis showed that in the loaded disc, the size of the nucleus was reduced and that the annular layer was disorganized. Based on the Masuda grading scale, scores were as follows: for the control group, 3.8 ± 0.35; sham, 4.2 ± 0.35; 1.8 N, 5.4 ± 0.35; 4.5 N, 7.6 ± 0.35; and 7.2 N, 10 ± 0.35. The gene expression was divided into the following: anabolic genes (aggrecan, collagen type1-α1, and collagen type2-α1) and catabolic genes (MMP-3 and MMP-13). Aggrecan and collagen type 2 were, respectively, downregulated from 0.42 ± 0.04 to 0.21 ± 0.04 and from 0.93 ± 0.06 to 0.17 ± 0.06 as the magnitude of compression increased, whereas collagen type 1 was significantly upregulated, from 2.49 ± 0.19 to 4.40 ± 0.19, when compared with the control group (from 1.8 to 7.2 N, P < 0.05). Catabolic genes MMP-3 and MMP-13 were significantly upregulated in all experimental groups (P < 0.05, MMP-3: from 1.46 ± 0.18 to 3.44 ± 0.18; MMP-13: from 1.19 ± 0.12 to 2.82 ± 0.13); however, MMP-13 exhibited no significant changes but tended to be upregulated when compared with the 1.8 N group with the 4.5 N group.

CONCLUSIONS

Different stresses led to different processes of degenerative changes, the concave disc degenerating more severely as stress gradually increased.

Electrical peripheral nerve stimulation relieves bone cancer pain by inducing Arc protein expression in the spinal cord dorsal horn

Objective

The analgesic effect on chronic pain of peripheral nerve stimulation (PNS) has been proven, but its underlying mechanism remains unknown. Therefore, this study aimed to assess the analgesic effect of PNS on bone cancer pain in a rat model and to explore the underlying mechanism.

Materials and methods

PNS on sciatic nerves with bipolar electrode was performed in both naïve and bone cancer pain model rats. Then, the protein levels of activity-regulated cytoskeleton-associated protein (Arc), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid–type glutamate receptor 1 (GluA1), and phosphate N-methyl-d-aspartic acid-type glutamate receptor subunit 2B (pGluNR2B) in spinal cord were evaluated by immunohistochemistry and Western blotting. Thermal paw withdraw latency and mechanical paw withdraw threshold were used to estimate the analgesic effect of PNS on bone cancer pain. Intrathecal administration of Arc shRNA was used to inhibit Arc expression in the spinal cord.

Results

PNS at 60 and 120 Hz for 20 min overtly induced Arc expression in the spinal cord, increased thermal pain thresholds in naïve rats, and relieved bone cancer pain; meanwhile, 10 Hz PNS did not achieve those results. In addition, PNS at 60 and 120 Hz also reduced the expression of GluA1, but not pGluNR2B, in the spinal cord. Finally, the anti-nociceptive effect and GluA1 downregulation induced by PNS were inhibited by intrathecal administration of Arc shRNA.

Conclusion

PNS (60 Hz, 0.3 mA) can relieve bone-cancer-induced allodynia and hyperalgesia by upregulating Arc protein expression and then by decreasing GluA1 transcription in the spinal cord dorsal horn.

Anti-apoptotic function of herpes simplex virus -2 latency-associated transcript RL1 sequence and screening of its encoded microRNAs

BACKGROUND

The latency-associated transcript (LAT) gene of herpes simplex virus (HSV)-2 is the only detectable viral gene expressed during latent infection in neurons. LAT inhibits apoptosis and maintains latency by promoting the survival of infected neurons. However, whether LAT functions during HSV-2 infection via its encoded RNAs or via its encoded proteins remain unknown. Increasing evidence has indicated that LAT is likely to functionally promote the establishment of latent infection via LAT-encoded microRNAs (miRNAs).

AIM

To explore whether the RL1 fragment of the five adjacent miRNAs has an effect on cell apoptosis, then provide supporting evidence to elucidate the potential role of these miRNAs and to aid screening of their cellular targets.

METHODS

A number of techniques, including MTT assay, flow cytometry and DNA ladder analysis, were used to verify the role of the RL1 fragment and the contribution of the individual miRNAs to the anti-apoptotic effect.

RESULTS

Five miRNAs (miR-H3, miR-H4-3p, miR-H4-5p, miR-H24 and miR-H19) were detected by quantitative PCR in PC12 cells stably expressing RL1 after pEGFP-RL1 plasmid transfection in vitro. The data indicated that expression of HSV-2 LAT RL1 seems to provide protection against apoptosis of PC12 cells induced by ActD. Antisense miRNAs specifically inhibiting these five miRNAs could efficiently reduce their expression. Transfection of antisense-miR-H3, antisense-miR-H4-5p and antisense-miR-H19 into PC12 cells stably expressing RL1 were able to partly reverse the anti-apoptotic effect of these miRNAs.

CONCLUSIONS

These findings indicate that the apoptotic role of the RL1 fragment is likely to be related to overexpression of miR-H3, miR-H4-5p and miR-H19 in PC12 cells.

Analysis of Pre- and Postoperative Pain Variation in Osteoporotic Vertebral Compression Fracture Patients Undergoing Kyphoplasty

Background

Balloon kyphoplasty (KP) has been widely applied in the treatment of elderly patients with osteoporosis vertebral compression fracture (OVCF), but there has been little research on the pain relief effect. Therefore, we performed this study of patients who received KP. The study included a set of fluoroscopy tests and follow-up evaluation, which aimed to verify the effectiveness of kyphoplasty in controlling back pain associated with OVCFs.

Material/Methods

Forty-three OVCF patients underwent kyphoplasty: 21 were allocated to an intervention group and 22 were allocated to a control group, and the 2 groups received treatment with different KP instruments. The variation of vertebral height was measured on X-ray and change of signal of MRI was recorded. The pain was assessed by VAS score and diagram, and physical function was evaluated by ODI. The complications after surgery were recorded and collated during 2 years of follow-up.

Results

The intervention group showed no significant difference on the VAS and ODI compared to the control group (p>0.05). There was no difference in the VAS with different degrees of radiological change (p>0.05). Signal change on MRI imaging was rare.

Conclusions

Kyphoplasty is a positive way to alleviate early-onset OVCF pain. The change of BME extent in the treated level is unrelated to the relief of back pain after KP.

Individual Collagen Fibril Thickening and Stiffening of Annulus Fibrosus in Degenerative Intervertebral Disc

STUDY DESIGN

In vitro study using rat intervertebral discs (IVDs).

OBJECTIVE

To explore the alteration of annulus fibrosus collagen fibrils after loading on IVD and to investigate the degeneration pathogenesis at the nanoscale.

SUMMARY OF BACKGROUND DATA

Abnormal loading can lead to IVD degeneration, but the precise mechanism has been hitherto elusive, especially at the nanoscale.

METHODS

A rat IVD loading model was used, which combined bending of the tail by 40° with compressive loading of 1.8, 4.5, and 7.2 N of the rat tail using an external fixation device. The structure and the elastic modulus of individual collagen fibrils within IVD Co8-Co9 was examined 2 weeks after loading at the nanoscale using atomic force microscopy.

RESULTS

Significant fibril disorder and a decrease in cell number within the annulus fibrosus after loading was observed at the microscale as judged by hematoxylin/eosin staining, suggesting initiation of rupture of the structure and degradation of the IVD. The annulus fibrosus collagen fibrils underwent a change in diameter and elastic modulus from 170 ± 18 to 310 ± 24 nm (P < 0.001) and 0.86 ± 0.12 to 1.27 ± 0.30 GPa (P = 0.003), respectively when measured on the concave side after a loading of 7.2 N. Thus the loading process resulted in a thickening and stiffening of collagen fibrils with a difference between the inner and outer layers.

CONCLUSION

The results of the present study indicated that abnormal loading was not only associated with disorder at the microscale, but also alteration of the collagen fibrils at the nanoscale, possibly leading to changes in the mechanical and physiological environment around the cells of the annulus fibrosus.

LEVEL OF EVIDENCE

N/A.

Metformin reduces SATB2-mediated osteosarcoma stem cell-like phenotype and tumor growth via inhibition of N-cadherin/NF-kB signaling

OBJECTIVE

To investigate the role of SATB2 in stem cell-like properties of osteosarcoma and identify new strategies to eliminate cancer stem cells of osteosarcoma.

MATERIALS AND METHODS

Osteosarcoma cancer stem cells were derived by sarcosphere generation or chemo drug enrichment. SATB2 and pluripotency-associated gene expression in osteosarcoma CSCs were analyzed using qRT-PCR and Western blotting. The sphere formation assay, cell counting kit-8 assay and anti-chemotherapy proteins were used to measure the effects of altered SATB2, N-cadherin expression or metformin treatment in CSCs. Nude mice were injected with SATB2-deficient U2OS/MTX cells to assess the role of SATB2 in osteosarcoma growth and chemoresistance in vivo. Bioinformatics analyses were performed to identify SATB2 downstream target genes and immunochemistry to determine the correlation between SATB2 expression and patient outcome. Western blotting and luciferase reporter assays were used to examine the effects of N-cadherin and SATB2 inhibition on the NF-kB pathway.

RESULTS

SATB2 was upregulated in osteosarcoma stem cells. Knockdown of SATB2 decreased sarcosphere formation, cell proliferation and stem cell-like gene expression in vitro, meanwhile reduced tumor growth and chemoresistance in vivo. High SATB2 expression in osteosarcoma patient samples was associated with poor clinical outcome. N-cadherin was one critical downstream target gene of SATB2 that mediated the stem cell-like phenotype. Reduction of SATB2 or N-cadherin resulted in NF-kB inactivation, which led to impaired osteosarcoma sphere formation and tumor cell proliferation. Metformin treatment of osteosarcoma cells enhanced the effects of chemotherapy via suppression of N-cadherin.

CONCLUSIONS

SATB2 plays an important role in regulating osteosarcoma stem cell-like properties and tumor growth. The combination of conventional chemotherapy and metformin may be a promising therapeutic strategy for osteosarcoma patients.

Retrospective analysis of 20 cases of refractory Hodgkin's lymphoma

We investigate the clinical characteristics, prognosis and treatment of relapsed and refractory Hodgkin's lymphoma. Twenty patients with relapsed and refractory Hodgkin lymphoma were treated by chemotherapy or autologous stem cell transplantation in our hospital from April 2006 to August 2012. The retrospective analysis of the records from the 20 patients reflected both 5-year overall survival (OS) and progression-free survival (PFS). The overall effectiveness was 80% for the 20 patients. The 5-year overall survival rate and 5-year progression-free survival rate were 73.5% and 62.7%, respectively. Therefore, comprehensive treatment should be actively utilized in the case of invalid second-line regimen for the refractory HL patients.

The diagnostic accuracy of magnetic resonance imaging for anterior cruciate ligament injury in comparison to arthroscopy: a meta-analysis

We performed this meta-analysis to examine the diagnostic accuracy of MRI for the diagnosis of anterior cruciate ligament (ACL) injury in comparison to arthroscopy. We also compared the diagnostic accuracy of MRI with magnetic field intensities (MFI) greater than or equal to 1.5T with those below 1.5T, in addition to different MRI sequences. Studies relevant to the diagnosis of ACL injury by MRI and arthroscopy were analyzed. Computer and manual retrieval were carried out on studies published between January 1, 2006 and May 31, 2016. Twenty-one papers were included. Neither threshold nor non-threshold effects were present (p = 0.40, p = 0.06). The pooled sensitivity (SE), specificity (SP), positive likelihood ratio (LR+), negative likelihood ratio (LR−) and diagnostic odds ratio (DOR) with 95% confidence interval (CI) were 87% (84–90%), 90% (88–92%), 6.78 (4.87–9.44), 0.16 (0.13–0.20) and 44.70 (32.34–61.79), respectively. The area under the curve (AUC) was 0.93. The risk of publication bias was negligible (p = 0.75). In conclusion, examination by MRI is able to provide appreciable diagnostic performance. However, the principle, which states that the higher the MFI, the better the diagnostic accuracy, could not be verified. Additionally, conventional sequences (CSs) associated with proton density-weighted imaging (PDWI) are only slightly better than CSs alone, but not statistically different.

Deterioration of the mechanical properties of calcium phosphate cements with Poly (γ-glutamic acid) and its strontium salt after in vitro degradation

The mechanical reliability of calcium phosphate cements has restricted their clinical application in load-bearing locations. Although their mechanical strength can be improved using a variety of strategies, their fatigue properties are still unclear, especially after degradation. The evolutions of uniaxial compressive properties and the fatigue behavior of calcium phosphate cements incorporating poly (γ-glutamic acid) and its strontium salt after different in vitro degradation times were investigated in the present study. Compressive strength decreased from the 61.2±5.4MPa of the original specimen, to 51.1±4.4, 42.2±3.8, 36.8±2.4 and 28.9±3.2MPa following degradation for one, two, three and four weeks, respectively. Fatigue life under same loading condition also decreased with increasing degradation time. The original specimens remained intact for one million cycles (run-out) under a maximum stress of 30MPa. After degradation for one to four weeks, the specimens were able to withstand maximum stress of 20, 15, 10 and 10MPa, respectively until run-out. Defect volume fraction within the specimens increased from 0.19±0.021% of the original specimen to 0.60±0.19%, 1.09±0.04%, 2.68±0.64% and 7.18±0.34% at degradation time of one, two, three and four weeks, respectively. Therefore, we can infer that the primary cause of the deterioration of the mechanical properties was an increasing in micro defects induced by degradation, which promoted crack initiation and propagation, accelerating the final mechanical failure of the bone cement. This study provided the data required for enhancing the mechanical reliability of the calcium phosphate cements after different degradation times, which will be significant for the modification of load-bearing biodegradable bone cements to match clinical application.

Comparative genomic analysis of Mycobacterium neoaurum MN2 and MN4 substrate and product tolerance

The microbial bioconversion of sterols can afford valuable steroid precursors, such as 4-androstene-3,17-dione (AD) and androsta-1,4-diene-3,17-dione (ADD). The Mycobacterium neoaurum MN4 mutant strain can produce AD in high yield and can tolerate a higher concentration of the substrate phytosterol than the parent strain M. neoaurum MN2. In order to further investigate the mechanisms underlying the enhanced substrate and product tolerance, we performed a genomic analysis of the MN2 and MN4 strains. The genomes were sequenced using a high-throughput approach and analyzed using software for genome assembly, gene prediction and functional annotation, KEGG (Kyoto Encyclopedia of Genes and Genomes) annotation, COG (cluster of orthologous) group cluster analysis, GO cluster analysis, and SNP detection and annotation. Based on comparative genomics, 184 mutations were identified in MN4, the average variant rate of 1 variant every 27,249 bases, with a TS/TV value of 0.5877 and missense mutations in one key sterol degradation genes (ChoM1) and four side chain degradation genes that encode enzymes catalysing β-oxidation. The results suggest the high AD yield might be due to mutation of ChoM and genes encoding FadE, FadB and FadA β-oxidation enzymes. This study provides a theoretical basis for further functional genomics analysis and heterologous production of M. neoaurum MN2 secondary metabolites.

[Expression and prognostic significance of microenvironment related prognostic factors in patients with classical Hodgkin's lymphoma]

Objective: To observe the expression of three microenvironment related prognostic factors, i. e. programmed death 1 (PD-1), forkhead box protein 3(FOXP3) and colony-stimulating factor 1 receptor(CSF-1R) protein in classical Hodgkin's lymphoma (CHL) patients, and to explore the correlation between the protein expression and the prognosis of the patients. Methods: A total of 45 cases of CHL patients, who had been admitted to the Tianjin Medical University Cancer Institute and Hospital and Chinese PLA General Hospital from February 2005 to August 2010 were analyzed, including clinical features, prognostic factors, and treatment regimens. CHL patients' specimens were collected and the expression of PD-1, FOXP3, and CSF-1R proteins analyzed by immunohistochemical staining. Epstein-Barr virus encoded mRNA (EBER) was detected by in situ hybridization analysis. The relationship between the protein expression of PD-1, FOXP3 and CSF-1R and the patients' outcome was analyzed with clinical and follow-up data. Survival analysis was performed by Kaplan-Meier method, the Cox proportional hazard model was used to perform multivariate analysis. Results: In this cohort of 45 CHL patients, PD-1 positive was found in 7 cases (15.6%), FOXP3 high expression in 23 cases (51.1%), CSF-1R positive in 18 cases (40.0%). In the univariate analysis, the expression of FOXP3 and CSF-1R, International Prognostic Index (IPI) score, Ann Arbor stage and EBER were related with the patients' 5-year overall survival (OS); IPI score, the expression of FOXP3 and EBER were related with the patients' 5-year progress-free survival (PFS). Multivariate analysis indicated that CSF-1R protein expression was the independent prognostic factor affecting the patients' 5-year OS(HR: 8.918, P=0.020), and FOXP3 protein expression was the independent prognostic factor affecting the patients' 5-year PFS (HR: 0.122, P<0.001). And EBV was an independent prognostic factor of PFS and OS in the CHL patients. Conclusion: Microenvironment related prognostic factors FOXP3, CSF-1R and EBV may be independent prognostic factors of CHL and this study may provide novel strategies for targeted therapy of CHL.

[Clinical analysis of 9 cases with Anti-leucine-rich glioma inactivated 1 protein antibody associated limbic encephalitis]

Objective: This study was to describe the clinical characteristics of Anti-leucine-rich glioma inactivated 1 protein(LGI1) antibody associated limbic encephalitis. Methods: Clinical data including clinical features, laboratory and radiological findings, treatment and prognosis of the 9 patients were analyzed. Results: In all 9 cases, 6 cases experienced epileptic seizure, 5 cases had psychosis, 7 cases presented with memory impairment, 4 cases showed faciobrachial dystonic seizure, 2 had refractory hyponatremia. One case presented with typically acute Guillain-Barre syndrome (GBS). Anti-LGI1 antibody was detected in 6 cases in cerebrospinal fluid (CSF) samples and 9 in serum samples. Seven cases out of 9 had brain imaging abnormalities. All 9 cases found no evidence of tumors. Eight cases were given immune therapy. During a 1-16 months follow-up, 1 case had complete recovery, 5cases had various degree of sequelae , among whom 4 had memory disturbance and 1 case had changed personality. 2cases were lost to follow-up. Conclusions: Limbic encephalitis is the most common manifestation of anti-LGI1 antibody associated encephalitis. Faciobrachial dystonic seizure (FBDS) is a specific symptom which favors an early diagnosis. Tumor is uncommon to see. The disease has a relatively favorable prognosis while impaired memory can be seen as a common sequelae.

[Misdiagnosis and associated costs of benign paroxysmal positional vertigo]

Objective: The aims of this study were to investigate the misdiagnosis of benign paroxysmal positional vertigo (BPPV) and to estimate the associated costs. Methods: During October 2015 to December 2015, eighty patients were diagnosed with BPPV in the outpatient dizziness clinic of Shanghai Changzheng Hospital and the clinical data of all the 80 patients were collected including the demographic and clinical characteristics, the history of diagnosis, inappropriate diagnostic tests, costs of the medical tests, transportation and accommodation. All the data were investigated to estimate the misdiagnosis of benign paroxysmal positional vertigo and the associated costs in Shanghai, China. Results: This study showed that the misdiagnosis rate of BPPV was 60.0% (48/80) and the common inappropriate diagnostic tests for BPPV included Cranial CT and MRI test, cervical MRI, cervical and cerebrovascular investigations et al. There was no significant difference between the misdiagnosis patients (48) and patients without misdiagnosis (32) in gender, age, duration of symptom, involved canal and type of BPPV.Complications were significantly more frequent in the misdiagnosis group than for those without[81.3%(39 /48) vs 34.4%(11 /32)]. The estimated costs for each misdiagnosed individual were 8 502.98 China Yuan (CNY) and one-year economic burden associated with the misdiagnosis of BPPV in Shanghai was 13.184 7-78.862 1 million CNY. Conclusions: Our study suggests that the misdiagnosis rate of BPPV is high and the financial impact on patients and society with this disease is huge. The cost-effective Dix-Hallpike or supine roll test maneuver should be used before applying other expensive medical tests in order to minimize misdiagnosis and the waste of health care resources.

Percutaneous Balloon Kyphoplasty in Treatment of Painful Osteoporotic Occult Vertebral Fracture: A Retrospective Study of 89 Cases

BACKGROUND The definition of a vertebral fracture is usually based on the presence of a deformation of the vertebral body and this can be misleading in the presence of a fracture without radiologic collapse with the definition of occult osteoporotic vertebral fractures (OOVFs). STIR sequence of MRI images showing hyperintensity signal was the most confirmative screening examination used to determine the presence of painful OOVFs. To date, clinical management of OOVFs has been rarely discussed. MATERIAL AND METHODS Between 2011 and 2013, 89 patients suffering from painful OOVFs underwent 142 percutaneous balloon kyphoplasty (PKP) procedures. Outcome data (mean variation of anterior and middle vertebral body height, visual analog scale [VAS] scores, Oswestry Disability Index [ODI] scores, and SF-36 scores) were recorded preoperatively, postoperatively, and at 1 month, 6 months, and 2 year after treatment, to evaluate the results. RESULTS We successfully treated 89 patients (142 vertebral bodies) with PKP. Cement leakages were observed in 12 (8.45%) treated vertebral bodies and there were 5 new adjacent vertebral fractures during the follow-up period. The mean variation of anterior and middle vertebral body height changed from 96.5±3.4% preoperatively to 97.2±2.5% postoperatively (p>0.05) and from 96.3±2.8% preoperatively to 97.9±3.1% postoperatively (p>0.05), respectively. The mean VAS scores were reduced significantly from pre-surgery to post-surgery (8.3±1.2 to 2.9±0.7; p<0.05), as was the ODI score (76.4±12.5 to 26.7±5.6; p<0.05). The SF-36 scores, including Bodily Pain (BF), Vitality (VT), Physical Function (PF), and Social Functioning (SF), all showed notable improvement (P<0.05). These variations were maintained during the 2-year follow-up period. CONCLUSIONS PKP is a safe and effective method in the treatment of painful OOVFs.

Treatment of Ribbing disease with 5-year follow-up and literature review

Ribbing disease, or multiple diaphyseal sclerosis, is a rare diaphyseal sclerosis of unknown etiology. Patients with this pathology usually present with asymmetric pain limited to the lower extremities. Though all efforts are made to relieve the progressive pain associated with Ribbing disease, no medical or surgical treatments have been established yet. In this case report, we followed up a Ribbing case with sclerotic bone fenestration for 5 years. The radiological changes and the clinical effects are described, and the different Ribbing treatments are then briefly reviewed.

N-acetylcysteine Attenuates Cobalt Nanoparticle-Induced Cytotoxic Effects through Inhibition of Cell Death, Reactive Oxygen Species-related Signaling and Cytokines Expression

OBJECTIVE

Complex cobalt-chromium alloys, bearing surfaces of the second-generation metal-on-metal (MoM) hip prostheses, are subject to wear and generate cobalt nanoparticles (CoNPs). CoNPs could reduce cellular viability, activate the mitogen-activated protein kinase (MAPK) pathway and increase cell apoptosis via reactive oxygen species (ROS). However, the detailed mechanisms of ROS functioning on CoNP-mediated signaling molecules and cytotoxicity has not yet been fully demonstrated. The present study investigated the functional role of N-acetylcysteine (NAC) in reversing the activation of ROS signaling pathways triggered by CoNPs in normal mice kidney cells (TCMK-1 cells).

METHODS

After being pretreated with NAC, TCMK-1 cells were treated with 300-700 μmol/L CoNPs, then, CCK-8 assay was used to verify the survival of TCMK-1 cells. Annexin V/PI staining was performed to investigate the apoptosis of TCMK-1 cells after NAC and different concentrations of CoNP treatments. In addition, western blot was performed to identify the cytokine (p-ERK, p-p38, and p-JNK) expression of the ROS-related MAPK signaling pathway.

RESULTS

Apoptosis rate of TCMK-1 cells was increased obviously after different concentrations of CoNP treatment. However, TCMK-1 cells, pretreated with NAC, exhibited a significantly decreased apoptosis rate. In addition, p-ERK, p-p38, and p-JNK expressions were increased with CoNP treatment, which indicated that CoNPs could activate the MAPK pathway. Interestingly, this entire stimulated phenomenon by CoNPs was reversed with NAC treatment.

CONCLUSIONS

These findings indicated that NAC could reverse CoNP-induced cytotoxicity by inhibiting ROS-induced cell death and cytokine expression. To our knowledge, this is the first report that describes how CoNP-induced cytotoxicity in TCMK-1 cells could be attenuated by anti-oxidative agents (NAC), which may function through inhibition of cell death and ROS.