Management of Infected Transforaminal Lumbar Interbody Fusion Cage in Posterior Degenerative Lumbar Spine Surgery

BACKGROUND

The postoperative infection rates for transforaminal lumbar interbody fusion (TLIF) have ranged from <2% to 4%. However, no consensus has been reached on the treatment strategies. TLIF cage preservation or revision surgery for lumbar spine reconstruction are 2 possible treatments. We aimed to determine the most effective method for organ/space infection control.

METHODS

The data from 4923 patients who had undergone TLIF with cage and posterior pedicle-screw instrumentation for spondylolysis or degenerative spondylolisthesis from January 2008 to December 2015 were retrospectively analyzed. Of the 4923 patients, 32 (0.65%) had developed organ/space infection of the interbody cage and were divided into 2 groups: those whose interbody cage was removed for revision (group 1) and those who interbody cage was retained (group 2). We compared the initial management of both groups in terms of age, sex, elapsed time to diagnosis, changes in spinal lordotic angle, visual analog scale score, fusion status, and Kirkaldy-Willis functional outcomes.

RESULTS

The 32 patients with organ/space infection had a mean age of 66.3 years and a follow-up period of 23.8 months. Significant differences were observed in the mean elapsed time to diagnosis (P = 0.004), lordotic angle correction at the disease level (P = 0.03), and Kirkaldy-Wallis functional outcomes (P = 0.01). Of the 17 patients undergoing debridement for implant retention, 9 (52.9%) exhibited poor results.

CONCLUSIONS

The most important factor contributing to TLIF cage retention failure was epidural fibrosis of the previous transforaminal route and biofilm adhesion on interbody devices affecting infection clearance. Thus, we would recommend a combined anterior and posterior approach or the transforaminal route for radical debridement with cage removal and fusion to achieve better clinical outcomes.

Using Percutaneous Endoscopic Outside-In Technique to Treat Selected Patients with Refractory Discogenic Low Back Pain

BACKGROUND

Controversy is not uncommon in the diagnosis of discogenic low back pain (DLBP) and in the identification of the location of the pain source for the symptomatic disc in patients with DLBP. Various techniques, from minimally invasive procedures to fusion surgery, are used to treat chronic DLBP, but the clinical outcomes are variable. Percutaneous endoscopic discectomy by transforaminal or interlaminar approach is considered to be an effective method to treat DLBP, but the evidence is limited; the lack of clear evidence may be associated with patient selection and surgical technique.

OBJECTIVES

The purpose of this study is to evaluate the clinical results of percutaneous endoscopic treatment for annular tear in selected patients with DLBP by using the outside-in technique.

STUDY DESIGN

A prospective study and retrospective observations were performed on 24 consecutive patients with a minimum 2 years of follow-up. This study was approved by the Institutional Review Board (IRB) of Buddhist Dalin Tzu-Chi General Hospital Foundation (IRB number: 10504004) and written informed consent was obtained from all patients.

SETTING

This research took place within an interventional pain management and spine practice.

METHODS

Twenty-four consecutive patients with single-level DLBP diagnosed by positive high-intensity zone on magnetic resonance imaging, positive provocative discography, and block test underwent a percutaneous endoscopic procedure from January 2014 to December 2015. The transforaminal approach or interlaminar approach was selected according to the location of the annular tear. The torn lesions were visualized directly and treated by puncture and debridement of the inflammatory tissues from the outer annulus fibrosus to the inner nucleus using the outside-in technique. The Visual Analog Scale (VAS) score and Oswestry Disability Index (ODI) score were evaluated before and after surgery. The clinical global outcomes were assessed on the basis of modified MacNab criteria.

RESULTS

These patients included 13 men and 11 women with a mean age of 43.8 years (range, 32-55 yrs). There were 15 lesion levels at L4/L5 and 9 lesion levels at L5/S1. Among them, 15 levels were accessed by transforaminal approach and 9 levels by interlaminar approach. No serious complications were observed during the follow-up periods. All except 2 patients experienced significant symptomatic and functional improvements at the 2-year follow-up with a success rate of 91.7%.

LIMITATIONS

Significant limitations include nonrandom format and small sample size. Future research may focus on controlled prospective studies with larger sample sizes and long-term follow-up to examine the validity of this protocol.

CONCLUSIONS

The percutaneous endoscopic procedure provides a safe and effective treatment for selected patients with DLBP. The outside-in technique allows the surgeons to visualize and treat the torn or inflammatory lesions directly, and the success rate is high at 2 years follow-up.

KEY WORDS

Transforaminal, interlaminar, outside-in technique, endoscopic discectomy, discogenic low back pain.

Synthesis of Linseed Oil-Based Waterborne Urethane Oil Wood Coatings

The linseed oil glyceride (LOG) was synthesized by using a transesterification process with a glycerol/linseed oil molar ratio of 1.0. The waterborne urethane oil (WUO) wood coating was prepared by acetone process. First, dimethylolpropionic acid was reacted with hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI), followed by adding LOG at various NCO/OH molars of 0.7, 0.8, and 0.9, respectively, and the COOH-containing prepolymer was obtained. Then, the ionomer which was prepared by neutralizing prepolymer with trimethylamine, was dispersed by adding deionized water, and the water⁻acetone dispersion was obtained. Finally, the acetone was removed by vacuum distillation. In the whole synthesized process, the LOG and COOH-containing prepolymer could be steadily synthesized by FTIR analysis, and the weight-average molecular weight and polydispersity of COOH-containing prepolymer increased with an increase of NCO/OH molar ratios. During the water dispersion process of the ionomer acetone solution, the point of phase inversion was prolonged, meaning the solid content decreased with an increase of NCO/OH molar ratios. After acetone was removed, the color of WUO was milky-white, and it was weakly alkaline and possessed a pseudoplastic fluid behavior. The particle size of WUO increased with increasing of NCO/OH molar ratios, however, the storage stability was extended for HDI and shortened for IPDI synthesized with increasing of NCO/OH molar ratios.

Elevated p53 Activities Restrict Differentiation Potential of MicroRNA-Deficient Pluripotent Stem Cells

Pluripotent stem cells (PSCs) deficient for microRNAs (miRNAs), such as Dgcr8^−/− or Dicer^−/– embryonic stem cells (ESCs), contain no mature miRNA and cannot differentiate into somatic cells. How miRNA deficiency causes differentiation defects remains poorly understood. Here, we report that miR-302 is sufficient to enable neural differentiation of differentiation-incompetent Dgcr8^−/− ESCs. Our data showed that miR-302 directly suppresses the tumor suppressor p53, which is modestly upregulated in Dgcr8^−/− ESCs and serves as a barrier restricting neural differentiation. We demonstrated that direct inactivation of p53 by SV40 large T antigen, a short hairpin RNA against Trp53, or genetic ablation of Trp53 in Dgcr8^−/− PSCs enables neural differentiation, while activation of p53 by the MDM2 inhibitor nutlin-3a in wild-type ESCs inhibits neural differentiation. Together, we demonstrate that a major function of miRNAs in neural differentiation is suppression of p53 and that modest activation of p53 blocks neural differentiation of miRNA-deficient PSCs.

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miR-302 enables neural differentiation of differentiation-incompetent Dgcr8^−/− ESCs

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miR-302 directly suppresses p53 expression

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p53 inhibits neural differentiation of Dgcr8^−/− and wild-type PSCs

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p53 may eliminate genetically defective embryos to save maternal resources

The role of cardiolipin in promoting the membrane pore-forming activity of BAX oligomers

BCL-2-associated X (BAX) protein acts as a gatekeeper in regulating mitochondria-dependent apoptosis. Under cellular stress, BAX becomes activated and transforms into a lethal oligomer that causes mitochondrial outer membrane permeabilization (MOMP). Previous studies have identified several structural features of the membrane-associated BAX oligomer; they include the formation of the BH3-in-groove dimer, the collapse of the helical hairpin α5-α6, and the membrane insertion of α9 helix. However, it remains unclear as to the role of lipid environment in determining the conformation and the pore-forming activity of the BAX oligomers. Here we study molecular details of the membrane-associated BAX in various lipid environments using fluorescence and ESR techniques. We identify the inactive versus active forms of membrane-associated BAX, only the latter of which can induce stable and large membrane pores that are sufficient in size to pass apoptogenic factors. We reveal that the presence of CL is crucial to promoting the association between BAX dimers, hence the active oligomers. Without the presence of CL, BAX dimers assemble into an inactive oligomer that lacks the ability to form stable pores in the membrane. This study suggests an important role of CL in determining the formation of active BAX oligomers.

The Impact of the Shallow-Trench Isolation Effect on Flicker Noise of Source Follower MOSFETs in a CMOS Image Sensor

The flicker noise of source follower transistors is the dominant noise source in image sensors. This paper reports a systematic study of the shallow trench isolation effect in transistors with different sizes under high temperature conditions that correspond to the quantity of empty defect sites. The effects of shallow trench isolation sidewall defects on flicker noise characteristics are investigated. In addition, the low-frequency noise and subthreshold swing degrade simultaneously in accordance to the device gate width scaling. Both serious subthreshold leakage and considerable noise can be attributed to the high trap density near the STI edge. Consequently, we propose a coincidental relationship between the noise level and the subthreshold characteristic; its trend is identical to the experiments and simulation results.

Anatomically realistic ultrasound phantoms using gel wax with 3D printed moulds

Here we describe methods for creating tissue-mimicking ultrasound phantoms based on patient anatomy using a soft material called gel wax. To recreate acoustically realistic tissue properties, two additives to gel wax were considered: paraffin wax to increase acoustic attenuation, and solid glass spheres to increase backscattering. The frequency dependence of ultrasound attenuation was well described with a power law over the measured range of 3–10 MHz. With the addition of paraffin wax in concentrations of 0 to 8 w/w%, attenuation varied from 0.72 to 2.91 dB cm⁻¹ at 3 MHz and from 6.84 to 26.63 dB cm⁻¹ at 10 MHz. With solid glass sphere concentrations in the range of 0.025–0.9 w/w%, acoustic backscattering consistent with a wide range of ultrasonic appearances was achieved. Native gel wax maintained its integrity during compressive deformations up to 60%; its Young’s modulus was 17.4  ±  1.4 kPa. The gel wax with additives was shaped by melting and pouring it into 3D printed moulds. Three different phantoms were constructed: a nerve and vessel phantom for peripheral nerve blocks, a heart atrium phantom, and a placental phantom for minimally-invasive fetal interventions. In the first, nerves and vessels were represented as hyperechoic and hypoechoic tubular structures, respectively, in a homogeneous background. The second phantom comprised atria derived from an MRI scan of a patient with an intervening septum and adjoining vena cavae. The third comprised the chorionic surface of a placenta with superficial fetal vessels derived from an image of a post-partum human placenta. Gel wax is a material with widely tuneable ultrasound properties and mechanical characteristics that are well suited for creating patient-specific ultrasound phantoms in several clinical disciplines.

Generation of FHL2 homozygous knockout lines from human embryonic stem cells by CRISPR/Cas9-mediated ablation

Cardiovascular disease is the leading cause of morbidity and mortality in the world. Mutations in the FHL2 (Four and a half LIM domains protein 2) gene are associated with cardiomyopathy in patients. Here, we generated two homozygous knockout lines using CRISPR/Cas9-mediated ablation in a human embryonic stem cell (hESC) WA09 line. These knockout lines exhibit a normal karyotype without expressing FHL2 protein, while maintaining pluripotency and differentiation properties. These isogenic mutation lines will be provided as a disease model for cardiomyopathy studies and drug screening.

Welding Silver Nanowire Junctions for Transparent Conducting Films by a Rapid Electroplating Method

A simple electrochemical method is developed in this study to weld the contact points in silver nanowire (AgNW) thin films. The AgNW thin film is first fabricated by spray coating and then submerged in a silver plating solution. By applying electrical potential over the AgNW thin films, silver ions in the plating solution are reduced into silver nanoparticles preferentially over nanowires and solder the nanomesh structures. Due to the large current density between silver nanowires, nanoparticles generated in the electroplating reaction mainly appeared at the junction. The electroplated AgNW network not only shows better conductivity with a negligible loss of transmittance, but also exhibit much better mechanical strength in the bending test.

Surgical outcome of atypical subtrochanteric and femoral fracture related to bisphosphonates use in osteoporotic patients with or without teriparatide treatment

Background

Atypical subtrochanteric fracture and femoral fracture have been considered to be rare complications related to long-term bisphosphonates use. A reduced bone turnover rate may lead to delayed bone healing. Limited data have revealed that teriparatide treatment may reverse the effect of bisphosphonates and be effective in bone healing.

Methods

We reviewed patients with atypical subtrochanteric and femoral fracture related to bisphosphonates use between January 2008 and December 2014. Thirteen female patients were enrolled. Radiographic findings were compatible with the characteristics of atypical fracture. Surgical intervention was performed for all, and teriparatide use was advised postoperatively. Outcome measures included perioperative results, and clinical and radiographic outcome.

Results

Of the 13 female patients enrolled, 10 had subtrochanteric and 6 had proximal femoral fracture; 3 had bilateral fractures. The mean age of the patients at surgery was 70.15±6.36 years. Most fractures (68.8%) presented prodromal thigh pain. All patients were treated with an intramedullary fixation system without severe complications. The patients were divided into 2 groups based on whether they had received treatment with teriparatide or not. The mean time to bone union was 4.4 months in the teriparatide-treated group, and 6.2 months in the non-teriparatide-treated group (p=0.116). Six patients (75%) in the teriparatide-treated group and 4 (50%) in the non-teriparatide-treated group (p= 0.3) achieved bone union within 6 months. The means of the modified Harris Hip Score and Numerical Rating Scale were significantly better in the teriparatide-treated group at postoperative 6 months. Seven patients had the same ability to walk at the 1-year follow-up as they did before the atypical fracture.

Conclusions

Teriparatide treatment in patients with atypical fracture may help in fracture healing, hip function recovery, and pain relief in this reduced bone turnover patient group.

MicroRNA-30a increases tight junction protein expression to suppress the epithelial-mesenchymal transition and metastasis by targeting Slug in breast cancer

The epithelial-to-mesenchymal (EMT) transition is a prerequisite for conferring metastatic potential during tumor progression. microRNA-30a (miR-30a) expression was significantly lower in aggressive breast cancer cell lines compared with non-invasive breast cancer and non-malignant mammary epithelial cell lines. In contrast, miR-30a overexpression reversed the mesenchymal appearance of cancer cells to result in a cobblestone-like epithelial phenotype. We identified Slug, one of the master regulators of EMT, as a target of miR-30a using in silico prediction. Reporter assays indicated that miR-30a could bind to the 3'-untranslted region of Slug mRNA. Furthermore, we linked miR-30a to increased expression of claudins, a family of tight junction transmembrane proteins. An interaction between Slug and E-box in the claudin promoter sequences was reduced upon miR-30a overexpression, further leading to reduction of filopodia formation and decreased invasiveness/metastasis capabilities of breast cancer cells. Consistently, delivery of miR-30a in xenografted mice decreased tumor invasion and migration. In patients with breast cancer, a significantly elevated risk of the miR-30alow/CLDN2low/FSCNhigh genotype was observed, linking to a phenotypic manifestation of larger tumor size, lymph node metastasis, and advanced tumor stage among patients. In conclusion, the miR-30a/Slug axis inhibits mesenchymal tumor development by interfering with metastatic cancer cell programming and may be a potential target for therapy in breast cancer.

Distinct stages of synapse elimination are induced by burst firing of CA1 neurons and differentially require MEF2A/D

Experience and activity refine cortical circuits through synapse elimination, but little is known about the activity patterns and downstream molecular mechanisms that mediate this process. We used optogenetics to drive individual mouse CA1 hippocampal neurons to fire in theta frequency bursts to understand how cell autonomous, postsynaptic activity leads to synapse elimination. Brief (1 hr) periods of postsynaptic bursting selectively depressed AMPA receptor (R) synaptic transmission, or silenced excitatory synapses, whereas more prolonged (24 hr) firing depressed both AMPAR and NMDAR EPSCs and eliminated spines, indicative of a synapse elimination. Both synapse silencing and elimination required de novo transcription, but only silencing required the activity-dependent transcription factors MEF2A/D. Burst firing induced MEF2A/D-dependent induction of the target gene Arc which contributed to synapse silencing and elimination. This work reveals new and distinct forms of activity and transcription-dependent synapse depression and suggests that these processes can occur independently.

Training effect of a stationary preprogrammed target dummy on visual response time and contest performance of karate athletes

BACKGROUND

Response time (RT) is crucial in karate athletes and can be trained. The aim of this study was to compare standing eye-hand RT and contest performance in nonelite karate athletes who underwent 6 weeks of training using either a stationary preprogrammed target dummy (experimental group) or traditional karate instruction (control group).

METHODS

Forty male nonelite karate athletes (20 in each group) were recruited. Standing RT and contest performance was assessed before and after training. Attack RT (eye-hand or eye-leg) and success rate were measured in the experimental group only during training.

RESULTS

Age, years of karate practice, Body Mass Index, and standing RT before training did not significantly differ between groups. In the control group, standing RT was significantly improved in the dominant hand after training (25.62±24.18 ms, P=0.0003), but there was no significant improvement in standing RT of the nondominant hand and karate contest score. In the experimental group, standing RT was significantly faster after training (improvement in dominant hand: 69.84±50.85 ms, P<0.0001; improvement in nondominant hand: 68.94±59.43 ms, P<0.0001), and the karate contest score was significantly improved (P=0.0234). During the training period, mean attack RT improved from 1047.4 ms in week1 to 944.9 ms in week6 (P<0.001). However, the success rate gradually decreased from 89.3% (week 1) to 62.4% (week 6) (P<0.001).

CONCLUSIONS

A 6-week training using a stationary preprogrammed target dummy improved contest performance and standing RT in both the dominant and nondominant hands of nonelite karate athletes. Improvements of RT in the dominant hand were also seen in the control group.

Stability Analysis of Printed Liquid Elbows

In this study, a theoretical model was developed to analyze the stability of liquid elbow patterns and validated by experiments. An exemplar system of ethylene glycol continuously deposited on polyethylene terephthalate (PET) was used to study the effects of printing parameters on bulge formation near the elbow corners. In the elbow region, because of the capillary pressure differences, liquids flowed into the concave elbow corner and formed bulges easily after being printed. However, the bulge formation disappeared when the elbow angle is >90°. A simple model based on surface energy analysis was proposed to explain the bulging phenomenon and can successfully predict bulge sizes at steady state. A stability diagram was also calculated to map out the stable regimes. With the guidance of the stability diagram, stable elbow lines without any bulges can be printed with various angles by controlling the thickness of liquids. In summary, this stabilization strategy in this study is effective to maintain the fidelity of printed liquid patterns and provides useful guidelines for printed electronic applications.

Accelerated Sedimentation Velocity Assessment for Nanowires Stabilized in a Non-Newtonian Fluid

In this work, the long-term stability of titanium oxide nanowire suspensions was accessed by an accelerated sedimentation with centrifugal forces. Titanium oxide (TiO₂) nanoparticle (NP) and nanowire (NW) dispersions were prepared, and their sizes were carefully characterized. To replace the time-consuming visual observation, sedimentation velocities of the TiO₂ NP and NW suspensions were measured using an analytical centrifuge. For an aqueous TiO₂ NP suspension, the measured sedimentation velocities were linearly dependent on the relative centrifugal forces (RCF), as predicted by the classical Stokes law. A similar linear relationship was also found in the case of TiO₂ NW aqueous suspensions. However, NWs preferred to settle parallel to the centrifugal direction under high RCF because of the lower flow resistance along the long axis. Thus, the extrapolated sedimentation velocity under regular gravity can be overestimated. Finally, a stable TiO₂ NW suspension was formulated with a shear thinning fluid and showed great stability for weeks using visual observation. A theoretical analysis was deduced with rheological shear-thinning parameters to describe the nonlinear power-law dependence between the measured sedimentation velocities and RCF. The good agreement between the theoretical predictions and measurements suggested that the sedimentation velocity can be properly extrapolated to regular gravity. In summary, this accelerated assessment on a theoretical basis can yield quantitative information about long-term stability within a short time (a few hours) and can be further extended to other suspension systems.

The Universal 3D3 Antibody of Human PODXL Is Pluripotent Cytotoxic, and Identifies a Residual Population After Extended Differentiation of Pluripotent Stem Cells

Podocalyxin-like protein (PODXL) is a member of CD34 family proteins. It is the protein that carries many post-translational epitopes responsible for various pluripotent surface markers including TRA-1-60, TRA-1-81, GCTM2, GP200, and mAb84. However, PODXL has not attracted the attention of stem cell biologists. Here, we report several features of PODXL mRNA and protein in pluripotent stem cells. Similar to the modification-dependent pluripotent epitopes, PODXL transcripts and carrier protein are also features of pluripotency. PODXL is highly expressed in early human embryos from oocytes up to four-cell stages. During reprogramming of human cells to pluripotency, in contrast to TRA-1-60 and TRA-1-81, PODXL is activated by KLF4 at a very early time of reprogramming. Although TRA-1-60 and TRA-1-81 are completely lost upon differentiation, a residual PODXL(+) population exists even after extended differentiation and they were identified by the universal human PODXL epitope 3D3. Unlike TRA-1-60 and TRA-1-81 epitopes that are unique to primate pluripotent stem cells (PSCs), PODXL carrier protein can be used as a murine surface marker. Most importantly, antibody to 3D3 epitope causes massive necrosis and apoptosis of human PSCs (hPSCs). We suggest that 3D3 antibody could be employed to eliminate the tumorigenic pluripotent cells in hPSC-derived cells for cell transplantation.

EXTENDED-SPECTRUM BETA-LACTAMASE-PRODUCING ESCHERICHIA COLI AND KLEBSIELLA PNEUMONIAE ISOLATES FROM THE URINE OF DOGS AND CATS SUSPECTED OF URINARY TRACT INFECTION IN A VETERINARY TEACHING HOSPITAL

Extended-spectrum [Formula: see text]-lactamase (ESBL)-producing microorganisms often cause severe infections; they have only limited therapeutic alternatives and have emerged in both human and veterinary medicine. Companion animals have prolonged contact with humans and could serve as a reservoir for ESBL strains. Information regarding ESBL producers in companion animals is rather limited compared to that regarding humans. Therefore, the objective of this study was to screen for ESBL producers in Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis in urine samples collected from dogs and cats in which urinary tract infection was suspected in a veterinary teaching hospital in Taipei, Taiwan. In addition, bla genes, multilocus sequence typing (MLST) analysis, and antibiotic susceptibility testing were performed on these ESBL producers. From December 2011 to March 2013, disc tests of cefotaxime and ceftazidime, with and without clavulanic acid, were performed on 60 E. coli, 22 [Formula: see text]. pneumoniae, and 18 P. mirabilis samples isolated from urine; 2 E. coli and 5 K. pneumoniae samples with the ESBL phenotype were identified. CTX-M-15 was the most frequently found bla gene. CTX-M-14, SHV-11, SHV-12, and SHV-28 were also identified. MLST analysis did not detect a predominant ST type in either E. coli or [Formula: see text]. pneumoniae; nonetheless, K. pneumoniae ST15 and ST11, which are zoonotic agents of public health concern, were detected in our study. All ESBL-producing bacteria exhibited a multidrug-resistant phenotype. The occurrence of ESBL-producing E. coli and K. pneumoniae in companion animals underscores the importance of ESBL screening and epidemiological study in veterinary hospitals.