bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three body resonances in close orbiting planetary systems: tidal dissipation and orbital evolution
Authors: Papaloizou John C. B. 
Published: May 2014

AbstractWe study the orbital evolution of a three-planet system with masses in the super-Earth regime resulting from the action of tides on the planets induced by the central star which cause orbital circularization. We consider systems either in or near to a three-body commensurability for which adjacent pairs of planets are in a first-order commensurability. We develop a simple analytic solution, derived from a time averaged set of equations, that describes the expansion of the system away from strict commensurability as a function of time, once a state where relevant resonant angles undergo small amplitude librations has been attained. We perform numerical simulations that show the attainment of such resonant states focusing on the Kepler 60 system. The results of the simulations confirm many of the scalings predicted by the appropriate analytic solution. We go on to indicate how the results can be applied to put constraints on the amount of tidal dissipation that has occurred in the system. For example, if the system has been in a librating state since its formation, we find that its present period ratios imply an upper limit on the time average of 1/Q′, With Q′ being the tidal dissipation parameter. On the other hand if a librating state has not been attained, a lower upper bound applies.
Estimation of measurements for block‐based compressed video sensing: study of correlation noise in measurement domain
Authors: Song Bin , Guo Jie , Li Lingquan , Liu Haixiao 
Published: May 2014

Compressed video sensing (CVS) is an application of compressed sensing theory which samples a signal below the Shannon–Nyquist rate. However, previous research about CVS has largely ignored the inter‐frame correlation analysis in the measurement domain, and then is not able to remove the time redundancy. In this study, the authors consider the estimation of the measurements of a block in any possible position in a frame by introducing a correlation noise (CN) between the actual and the estimated measurements. In this work, they first establish a correlation model (CM) in the pixel domain between a block which is in a random unknown position in a frame and the adjacent non‐overlapping blocks that they already have. Then, a novel measurement domain CM is presented to approximate the measurements for the random block. Lastly, they employ the CN to characterise the accuracy of the CM in the measurement domain. The simulation results show that the proposed model can make an accurate estimation to the actual measurements of an arbitrary block in a frame and that by using the proposed CN to perform motion estimation, they can improve the peak signal‐to‐noise ratio of the video sequences by 0.1–1.7 dB compared with the existing methods.
The Impact of the Cage Height, Diameter, and Positioning on Clinical and Radiographic Outcome of the Extreme Lateral Interbody Fusion
Authors: Hofstetter C. P. , Alimi M. , Elowitz E. , Hartl R. 
Published: May 2014

Introduction Extreme lateral interbody fusion (ELIF) is a novel technique for anterior spinal fixation and indirect decompression of neural elements. Materials and Methods Retrospective analysis of 145 ELIFs in 90 patients. Cages measuring 8 to 14 mm in height were used. Intervertebral disc height, foraminal height, cage position, and lumbar lordosis were determined on preoperative, postoperative, and the latest follow-up studies. Clinical outcomes were evaluated by Oswestry disability index (ODI) and visual analog scale (VAS). Results At the time of last follow-up (17.7 ± 1.1 months), two factors determined restoration of foraminal height: First, the amount of oversizing the graft (implant height-preoperative disc height) showed a significant positive correlation with increase of foraminal height (Pearson correlation coefficient 0.691, p < 0.001). Implantation of cages 6 to 9 mm higher than the preoperative disc resulted in 3.1 ± 0.3 mm foraminal height increase. Thus, cages oversized by 6 to 9 mm yielded in significantly greater restoration of foraminal height compared with grafts that were oversized by 0 to 3 mm ( p < 0.01) or 3 to 6 mm ( p < 0.05). The second determinant of foraminal height restoration was the footprint of the intervertebral spacer. Approximately one half of our patients received 18 mm spacers and the other 22 mm grafts. Eighteen mm spacers allowed for a 2.1 mm increase of foraminal height while 22 mm spacers lead to an increase by 4.0 mm on postoperative radiographs ( p < 0.001). Interestingly, neither cage position nor posterior instrumentation had statistically significant influence on restoration of foraminal height. ELIF interbody grafts provided adequate anterior column support with 1.0 ± 0.1 mm subsidence on last follow-up imaging compared with immediate postoperative studies. Subsidence was significantly greater with intervertebral cages that were oversized by 0 to 3 mm (1.7 ± 0.5 mm) compared with cages oversized by 6 to 9 mm (0.8 ± 0.2 mm, p < 0.05). One-third of patients received lordotic spacers. Both, lordotic and nonlordotic cages allowed for increased lumbar lordosis on postoperative imaging (6.0 and 4.7 degrees, respectively). Clinical evaluation revealed a mean ODI, VAS back, buttock, and leg pain improvements of 21.1%, 3.7, 3.6, and 3.7 points, respectively. Conclusion In ELIF, cage width and height but not cage position determine restoration of foraminal height. Thus, optimum foraminal height restoration is achieved by using 22 mm wide cages oversized by 6 to 9 mm in height. Disclosure of Interest None declared
Intradiscal Administration of Tumor Necrosis Factor-α Inhibitor, Etanercept, Clinically Improves Intractable Discogenic Low Back Pain
Authors: Sainoh T. , Orita S. , Yamauchi K. , Sakuma Y. , Kubota G. , Oikawa Y. , Inage K. , Sato J. , Fujimoto K. , Takahashi K. , Ohtori S. 
Published: May 2014

Introduction Discogenic low back pain (LBP) has been clinically considered to be one of the sources of intractable LBP. Tumor necrosis factor-α (TNF-α) is one of the well-known pain-related proinflammatory mediators in the degenerative intervertebral disc. However, it is unclear whether its inhibition leads to any analgesic outcomes. In this study, we aimed to examine the effect of intradiscal TNF-α inhibitor administration in discogenic LBP patients. Materials and Methods Discogenic LBP patients were diagnosed on the basis of physical and radiographic (X-ray and magnetic resonance imaging) findings. Sixty patients were divided randomly into two groups: etanercept group ( n = 30; bupivacaine 2 mL with etanercept 10 mg) and control group ( n = 30; bupivacaine 2 mL). Numerical rating scale score for LBP before and 1 day, 1, 2, and 4 weeks after the injection and Oswestry disability index (ODI) score before and 4 weeks after the injection were evaluated. In addition, complications after the injection were evaluated. Results While both groups experienced considerable pain relief, the visual analog scale score significantly decreased in the etanercept group at every time point after the injection ( p < 0.05). The ODI score decreased 4 weeks after the injection only in the etanercept group ( p < 0.05). There were no complications in either group. Conclusion Single intradiscal administration of TNF-α inhibitor showed a greater analgesic effect without any complications lasting for 4 weeks, thereby implying that TNF-α may be profoundly involved in the pathogenesis of chronic discogenic LBP. The present study indicates that intradiscal administration of TNF-α inhibitor can be useful for intractable discogenic LBP treatment in humans. Disclosure of Interest None declared
BMPs Enhance in Vitro Tissue Regeneration by Human Degenerated Nucleus Pulposus Cells
Authors: Krouwels A. , Iljas L. , Plomp S. , Dhert W. , Oner C. , Creemers L. 
Published: May 2014

Introduction Bone morphogenetic proteins (BMPs) are currently being investigated for differentiation of stem cells or enhancement of tissue production for various cell types. It has been shown that heterodimers of BMPs can be more effective than the combined homodimers.1 In this study, we investigate whether this is also true for tissue regeneration by human degenerated NP cells. Materials and Methods Nucleus pulposus (NP) cells from a human donor (Thompson grade III) were cultured for 14 days in high density (1 × 10^6 cells/cm2) on collagen II coated filters. Several rhBMPs (BMP2, BMP4, BMP7, BMP2+7, BMP4+7 and the heterodimers of BMP2,7 and BMP4,7) were added to the culture medium (DMEM + 10% heat inactivated fetal bovine serum + 2% ascorbic acid-2-phosphate) in two different concentrations (total concentration 10 or 100 ng/mL medium). Control medium contained 10 ng/mL TGF-β2. Samples were stained with Safranin O for glycosaminoglycans (GAGs) and with immunohistochemistry for collagen II. Matrix content as reflected by GAG production was measured with a dimethylmethylene blue (DMMB) assay and DNA content with a PicoGreen assay. Statistical analyses included one-way ANOVA and post hoc Bonferroni. Results GAG per DNA was highest for BMP4 (see Fig. 1 for p values). At 10 ng/mL, the heterodimer of BMP2,7 resulted in more GAG/DNA than the homodimers combined ( p = 0.003) or BMP7 alone ( p = 0.003), but not for 100 ng/mL. GAG per DNA was higher at 100 ng/mL BMP versus 10 ng/mL for all BMPs ( p < 0.001). Conclusion In conclusion, BMP4 seems to be the most potent factor for improving matrix production by NP cells in vitro. The heterodimers of BMP2,7 and BMP4,7 do not seem to be clearly more effective for tissue production than the homodimers combined or alone, especially for higher concentrations. Disclosure of Interest None declared Reference Israel DI, Nove J, Kerns KM, et al. Heterodimeric bone morphogenetic proteins show enhanced activity in vitro and in vivo. Growth Factors 1996;13(3-4):291–300
Early Degeneration of Intervertebral Disc in HIF-1α-Deficiency Mouse
Authors: Zhang X. , Liang Y. , Wu W. , Cao P. 
Published: May 2014

Introduction Hypoxia-inducible factor-1α (HIF-1α) is one of the most important factors that mediate direct cellular response to hypoxia. Intervertebral disc is the largest avascular organ in human body, nucleus pulposus cells originating from mesenchymal tissue are in the hypoxia environment. HIF-1α has been reported to express in normal and degenerated intervertebral disc cells. But there is no intervertebral disc HIF-1α deficiency mice available for degeneration study till now. Materials and Methods Shh-Cre+/− and HIF-1αflox/flox mice were used to generate HIF-1α-deficiency mice in intervertebral disc which was confirmed by RT-PCR and in situ hybridization. Five mice of HIF-1α−/− and wild-type (WT) group received the radiographic and MRI study at 2, 4 weeks after birth. Histological observation, Safranin O/Fast green staining of intervertebral disc were performed in each group. QRT-PCR and Western blot were used to assay the changes of collagen II and aggrecan with growth in the discs of mutant and wild type mice. Results RT-PCR of tail snip confirmed the genotype of HIF-1α deficiency mice and in situ hybridization of HIF-1α showed the ablation of HIF-1α in the disc. Radiographic study showed narrowing of intervertebral disc was noted on 4 weeks age mice in gene deletion, compared with the WT group, MRI study showed signal in the nucleus pulposus area disappeared and became “dark disc” in the HIF-1α−/− groups, starting from 2 weeks age, while the signal intensity WT group discs did not show appreciable degeneration. Histological observation indicated early degeneration in 2 weeks age of mutant mice (2.53 ± 0.97), and no degeneration of disc in WT mice (1.67 ± 0.52). mRNA expression and protein secretion of maim matrix in disc: collagen II (col2α) and aggrecan were both decreased in HIF-1α deficiency mice compared with WT mice. Conclusion Shh can be used as promotor for Cre recombinase to delete HIF-1α in mice nucleus pulposus cells successfully. HIF-1α deficiency mice in the disc were phenotypically normal as the WT, but manifest degeneration of intervertebral disc as early as 2 weeks age. Disclosure of Interest None declared
Utilization of Stem Cells in Alginate for Nucleus Pulposus Tissue Engineering
Authors: Huang B. , Wang H. , Zhou Y. , Liu L. , Liu M. , Wang J. , Li C. , Zhang Z. , Chu T. , Xiong C. 
Published: May 2014

Introduction In a general view of anatomy, intervertebral disc is composed of three parts: annulus fibrosus, nucleus pulposus (NP), and cartilage endplate. Recently, several types of stem cells were successfully isolated from these corresponding regions, but up to now, no research was performed about which kind of stem cells is the most efficient candidate for NP tissue engineering or for stem cell-based disc regeneration therapy. Materials and Methods In this study, we compared the regenerative potentials of the above-mentioned three kinds of disc-derived stem cells with that of the classic bone marrow (BM)-mesenchymal stem cells (MSCs) in a rabbit disc degeneration model. By magnetic resonance imaging (MRI), X-ray, histology, and so on. Results We found that cartilage endplate-derived stem cells (CESCs) showed superior capacity compared with the annulus fibrosus-derived stem cells (AFSCs), nucleus pulposus-derived stem cells (NPSCs), and BM-MSCs ( p< 0.05); in addition, when comparing the CESC group with the normal control group, there existed no statistical difference in X-ray ( p>0.05). Those results demonstrated that the CESC-seeded alginate construct performed the most powerful ability for NP regeneration, while AFSCs showed the most inferior potency, NPSCs and BM-MSCs had similar regenerative capacity and located in the middle. Conclusion Our study showed that CESCs might act as an efficient seed cell source for NP tissue engineering, which paved a new way for the biological solution of disc degeneration diseases. Disclosure of Interest None declared
LMP-1 Suppresses Intervertebral Disc Degeneration by Inhibiting MMPs Expression
Authors: Zheng Z. , Liu H. , Pan H. 
Published: May 2014

Introduction LIM mineralization protein-1(LMP-1) is an intracellular regulatory molecule in bone formation. Previous studies have proved that it has beneficial effects on intervertebral disc regeneration in vitro and in vivo. However the mechanism of LMP-1 suppresses intervertebral disc degeneration remains unknown. The purpose of the present study was to identify the protective role of LMP-1 in a TNF-α induced intervertebral disc degeneration cell model. Materials and Methods TNF-α induced extracellular matrix degradation of rat nucleus pulposus cells (NPCs) was used to imitate intervertebral disc degeneration. Cultured NPCs were transfected with rLMP-1 siRNA to knock down the LMP-1 expression, sulfated glycosaminoglycan (sGAG) dyeing, real-time polymerase chain reaction (RT-PCR), and western blotting were used to analyze proteoglycan, mRNA, and protein levels, respectively. Two days later, the mRNA levels of MMPs were measured. Results In vitro experiments revealed that the sulfated glycosaminoglycan (sGAG) level was significantly reduced with the rLMP-1 siRNA treatment, while the mRNA level of MMP3 and MMP13 increased. TNF-α down-regulated the proteoglycan expression in NPCs, knocking down LMP-1 expression had significantly elevated levels of MMP3 and MMP13 mRNA, accompanied with the decrease of sGAG level. Conclusion LMP-1 suppresses TNF-α induced intervertebral disc degeneration by inhibiting MMPs expression. Disclosure of Interest None declared
MicroRNA-319 Regulates Chondrogenic Differentiation of Human Mesenchymal Stem Cells by Targeting SOX9
Authors: Shang J. , Liu H. , Zhou Y. 
Published: May 2014

Introduction Cartilage is an avascular tissue without innervations. Thus, it has really limited regeneration and repair capacity. Tissue-engineered cartilage is highly demanded for repairing cartilage defects in cartilage-related diseases. Mesenchymal stem cells (MSCs) are self-renewal and multipotent stem cells, which can differentiate into osteocytes, chondrocytes, and adipocytes. Several studies have shown that epigenetic regulation plays an important role in the chondrogenesis of MSCs. MicroRNAs (miRNAs) are a group of small noncoding single-strand RNAs which can bind to target mRNAs to modulate various biological processes. We are intended to find roles of miR-319 during chondrogenic differentiation of mesenchymal stem cells. Materials and Methods To investigate the roles of miR-319 in chondrogenic differentiation of human MSCs, we induced chondrogenic differentiation of MSCs. Chondrogenic differentiation of MSCs was identified by Alcian staining and RT-qPCR assays. Next, we used lentiviruses as vehicles to upregulate and downregulate miR-319. In addition, dual-luciferase reporter gene assay was done to identify target gene of miR-319. Western blot was done to identify changes of target protein. Results RT-qPCR assays were done on day 0, 7, 14, and 21. Results showed that level of miR-319 was decreased during chondrogenic differentiation of MSCs. Overexpression of miR-319 greatly inhibited Alcian staining and downregulated mRNA levels of chondrogenic marker genes, such as COL2A1, COMP, COL9a2, COL11A1, and ACAN. Similarly, underexpression of miR-319 promoted Alcian staining and upregulated mRNA levels of chondrogenic marker genes. Next, dual-luciferase reporter gene assay identified that SOX9 was the target gene of miR-319. Importantly, changes of miR-319 did not change mRNA level of SOX9, but changed protein level of SOX9. The results showed that miR-319 modulated SOX9 at posttranscriptional level. Conclusion In summary, our studies demonstrated that miR-319 inhibited chondrogenic differentiation of human MSCs by targeting SOX9. Disclosure of Interest None declared
Endogenous Bioactive Proteins in Three-Dimensional Cultured Nucleus Pulposus Cells of Herniated Intervertebral Discs: Identification of Potential Target Proteins for Gene Therapeutic Approaches
Authors: Hegewald A. A. , Fontana J. , Beierfuß A. , Thomé C. , Mern D. 
Published: May 2014

Introduction Painful degenerative disc diseases have been targeted by different biological treatment approaches. Nucleus pulposus (NP) cells play a central role in intervertebral disc (IVD) maintenance by orchestrating catabolic, anabolic, and inflammatory factors that affect the extracellular matrix. IVD degeneration is associated with imbalances of these factors, resulting in a catabolic inflammatory metabolism. Therefore, accurate knowledge about their quantity and quality with regard to matrix synthesis is vital for a rational gene therapeutic approach. Materials and Methods NP cells were isolated from 63 patients operated due to lumbar disc herniation (mean age 56/range 29-84 years). Then, three-dimensional culture with low-glucose was completed in a collagen type I scaffold for 4 weeks. Subsequently, cell proliferation evaluation was performed using 3-(4, 5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide and intracellular concentration of 28 endogenously expressed anabolic, catabolic, inflammatory factors and relevant matrix proteins was determined by enzyme-linked immunosorbent assay. Specimen-related grades of degeneration were confirmed by preoperative magnetic resonance imaging. Results Independent from gender, age, and grade of degeneration proliferation rates remained similar in all groups of NP cells. Progressive grades of degeneration, however, showed a significant influence on accumulation of selective groups of factors such as disintegrin and metalloproteinase with thrombospondin motifs 4 and 5, matrix metalloproteinase 3, metalloproteinase inhibitor 1 and 2, interleukin-1β, and interleukin-1 receptor. Along with these changes, the key NP matrix proteins aggrecan and collagen II decreased significantly. The concentration of anabolic factors bone morphogenetic proteins 2, 4, 6, and 7; insulin-like growth factor 1; and transforming growth factor β1 and 3, however, remained below the minimal detectable quantities. Conclusion The advantage of the relative mass value evaluation method is the ability to perform precise quantifications of protein concentrations. To our knowledge, this method has not been applied to analyze a broad array of endogenously expressed bioactive factors in NP cells from a larger number of human specimens. The findings indicate that progressive degenerative changes in NP may be problematic with regard to biologic treatment strategies. Hence, gene therapeutic interventions regulating relevant bioactive factors identified in this work might contribute to the development of regenerative treatment approaches for degenerative disc diseases. Disclosure of Interest None declared
Effects of Initial Boost with TGF-Beta 1 and Grade of Intervertebral Disc Degeneration on 3D Culture of Human Annulus Fibrosus Cells
Authors: Hegewald A. A. , Kaps C. 
Published: May 2014

Introduction Three-dimensional (3D) culture in porous biomaterials and stimulation with growth factors are known to be supportive for intervertebral disc cell differentiation and tissue formation. Unless sophisticated releasing systems are used, however, effective concentrations of growth factors are maintained only for a very limited amount of time in in vivo applications. Therefore, we investigated if an initial boost with transforming growth factor-β1 (TGF-β1) is capable to induce a lasting effect of superior cartilaginous differentiation in slightly and severely degenerated human annulus fibrosus (AF) cells. Materials and Methods Human AF tissue was harvested during surgical treatment of six adult patients with lumbar spinal diseases. Grading of disc degeneration was performed with magnet resonance imaging. AF cells were isolated and expanded in monolayer culture and rearranged three-dimensionally in a porous biomaterial consisting of stepwise absorbable poly-glycolic acid and poly-(lactic-co-glycolic) acid and a supportive fine net of nonabsorbable poly vinylidene fluoride. An initial boost of TGF-β1 or TGF-β1 and hyaluronan was applied and compared with controls. Matrix formation was assessed at days 7 and 21 by (1) histological staining of the typical extracellular matrix molecules proteoglycan, type I and type II collagens and by (2) real-time gene expression analysis of aggrecan, decorin, biglycan, type I, II, III, and X collagens as well as of catabolic matrix metalloproteinases MMP-2 and MMP-13. Results An initial boost with TGF-β1 or TGF-β1 and hyaluronan did not enhance the expression of characteristic AF matrix molecules in our 3D culture system. AF cells showed high viability in the progressively degrading biomaterial. Stratification by grade of intervertebral disc degeneration showed that AF cells from, both, slightly degenerated or severely degenerated tissue, are capable of significant upregulations of characteristic matrix molecules in 3D culture. AF cells from severely degenerated tissue, however, displayed significantly lower upregulations in some matrix molecules such as aggrecan. Conclusion We failed to show a supportive effect of an initial boost with TGF-β1 in our 3D culture system. This underlines the need for further investigations on growth factor releasing systems. Disclosure of Interest A. A. Hegewald has no conflict of interest and C. Kaps is an employee of TransTissue Technologies GmbH, which develops products in the field of regenerative medicine.