519 research outputs found

    Correlation of Early Outcomes and Intradiscal Interleukin-6 Expression in Lumbar Fusion Patients.

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    OBJECTIVE: To determine if there is correlation between intradiscal levels of interleukin-6 (IL-6) and early outcome measures in patients undergoing lumbar fusion for painful disc degeneration. METHODS: Intervertebral disc tissue was separated into annulus fibrosus/nucleus pulposus and cultured separately in vitro in serum-free medium (Opti-MEM). Conditioned media was collected after 48 hours. The concentration of IL-6 was quantified using enzyme-linked immunosorbent assay. Pearson correlation coefficients quantified relationships between IL-6 levels and pre- and postoperative visual analogue scale (VAS) back pain and Oswestry Disability Index (ODI), as well as change in VAS/ODI. RESULTS: Sixteen discs were harvested from 9 patients undergoing anterior lumbar interbody fusion (mean age, 47.4 years; range, 21-70 years). Mean preoperative and 6-month postoperative VAS were 8.1 and 3.7, respectively. Mean preoperative and postoperative ODI were 56.2 and 25.6, respectively. There were significant positive correlations between IL-6 expression and postoperative VAS (ρ = 0.38, p = 0.048) and ODI (ρ = 0.44, p = 0.02). No significant correlations were found between intradiscal IL-6 expression and preoperative VAS (ρ = -0.12, p = 0.54). Trends were seen associating IL-6 expression and change in VAS/ODI (ρ = -0.35 p = 0.067; ρ = -0.34, p = 0.08, respectively). A trend associated IL-6 and preoperative ODI (ρ = 0.36, p = 0.063). CONCLUSION: The direct association between IL-6 expression and VAS/ODI suggests patients with elevated intradiscal cytokine expression may have worse early outcomes than those with lower expression of IL-6 after surgery for symptomatic disc degeneration

    PN fast winds: Temporal structure and stellar rotation

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    To diagnose the time-variable structure in the fast winds of central stars of planetary nebulae (CSPN), we present an analysis of P Cygni line profiles in FUSE satellite far-UV spectroscopic data. Archival spectra are retrieved to form time-series datasets for the H-rich CSPN NGC 6826, IC 418, IC 2149, IC 4593 and NGC 6543. Despite limitations due to the fragmented sampling of the time-series, we demonstrate that in all 5 CSPN the UV resonance lines are variable primarily due to the occurrence of blueward migrating discrete absorption components (DACs). Empirical (SEI) line-synthesis modelling is used to determine the range of fluctuations in radial optical depth, which are assigned to the temporal changes in large-scale wind structures. We argue that DACs are common in CSPN winds, and their empirical properties are akin to those of similar structures seen in the absorption troughs of massive OB stars. Constraints on PN central star rotation velocities are derived from Fast-Fourier Transform analysis of photospheric lines for our target stars. Favouring the causal role of co-rotating interaction regions, we explore connections between normalised DAC accelerations and rotation rates of PN central stars and O stars. The comparative properties suggest that the same physical mechanism is acting to generate large-scale structure in the line-driven winds in the two different settings.Comment: Accepted for publication in MNRAS; 10 pages, 5 figure

    Spectroscopic determination of the fundamental parameters of 66 B-type stars in the field-of-view of the CoRoT satellite

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    We aim to determine the fundamental parameters of a sample of B stars with apparent visual magnitudes below 8 in the field-of-view of the CoRoT space mission, from high-resolution spectroscopy. We developed an automatic procedure for the spectroscopic analysis of B-type stars with winds, based on an extensive grid of FASTWIND model atmospheres. We use the equivalent widths and/or the line profile shapes of continuum normalized hydrogen, helium and silicon line profiles to determine the fundamental properties of these stars in an automated way. After thorough tests, both on synthetic datasets and on very high-quality, high-resolution spectra of B stars for which we already had accurate values of their physical properties from alternative analyses, we applied our method to 66 B-type stars contained in the ground-based archive of the CoRoT space mission. We discuss the statistical properties of the sample and compare them with those predicted by evolutionary models of B stars. Our spectroscopic results provide a valuable starting point for any future seismic modelling of the stars, should they be observed by CoRoT.Comment: 31 pages (including 14 pages online material), 32 figure

    Nuclear level densities and γ\gamma-ray strength functions of 111,112,113^{111,112,113}Sn isotopes studied with the Oslo method

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    The 111,112,113^{111,112,113}Sn isotopes have been studied with (p,dγp,d \gamma), (p,pγp,p^{\prime} \gamma), and (d,pγd,p \gamma) reactions to extract the nuclear level densities (NLDs) and γ\gamma-ray strength functions (GSFs) of these nuclei below the neutron separation energy by means of the Oslo method. The experimental NLDs for all three nuclei demonstrate a trend compatible with the constant-temperature model below the neutron separation energy while also being in good agreement with the NLDs of neighboring Sn isotopes, obtained previously with the Oslo-type and neutron evaporation experiments. The extracted microcanonical entropies yield 1.5\approx 1.5 kBk_B entropy of a valence neutron in both 111^{111}Sn and 113^{113}Sn. Moreover, the deduced microcanonical temperatures indeed suggest a clear constant-temperature behavior above \approx 3 MeV in 111,113^{111,113}Sn and above \approx 4.5 MeV in 112^{112}Sn. We observe signatures for the first broken neutron pairs between 2 and 4 MeV in all three nuclei. The GSFs obtained with the Oslo method are found to be in good agreement below the neutron threshold with the strengths of 112,114^{112,114}Sn extracted in the (p,pp,p^{\prime}) Coulomb excitation experiments.Comment: 13 pages, 9 figure

    Microvesicles derived from leukocytes in the peripheral blood of patients with external genital endometriosis

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    Endometriosis is a chronic gynecological disease, which poses a serious problem in terms of diagnosis and treatment. Despite decades of research, there are no specific signs and symptoms and no blood tests to clinically confirm the diagnosis, which makes timely diagnosis and treatment difficult. Therefore, the search for new markers for early non-invasive diagnosis of the disease remains relevant. Various subcellular structures involved in intercellular communication, in particular, microvesicles, can be considered promising biological markers for external genital endometriosis. The aim of this work was to assess the composition of microvesicles derived from leukocytes in the peripheral blood of patients with stage I-II of external genital endometriosis and the possibility of their use as markers of non-invasive diagnosis of peritoneal forms of endometriosis. The study involved 97 women aged 26-40 with stage I-II of external genital endometriosis, whose diagnosis was established intraoperatively and confirmed histologically. Pain syndrome was noted in all patients of the main group, with infertility also detected in 73.2% of the patients. The control group consisted of 20 patients, whose average age was 25.5±1.1 years, who were examined in connection with male infertility factor before the in vitro fertilization, and in whom, on the basis of intraoperative examination, presented no gynecological diseases, and no pain syndrome. Before the surgical intervention, peripheral blood was taken from all patients to determine the content of microvesicles derived from leukocytes. To isolate microvesicles, we used the previously described by M.P. Gelderman and J. Simak method. It was found that patients with stage I-II of external genital endometriosis experience an increase in the number of CD14+, CD16+ and CD54+CD14+ microvesicles in the peripheral blood by 1.1, 1.38 and 1.55 times, respectively, as well as a decrease in the number of CD45+CD4+, CD3+CD4+, CD3+CD8+ microvesicles by 1.2, 4 and 1.5 times, respectively, compared with patients from the control group. Therefore, in patients with stage I-II of external genital endometriosis, an increase in the relative number of CD54+CD14+ microvesicles in the peripheral blood above 5.22% can serve as a marker for early non-invasive diagnosis of the disease with sensitivity of 80.5% and specificity of 71%

    Picosecond Fluorescence Relaxation Spectroscopy of the Calcium-Discharged Photoproteins Aequorin and Obelin

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    Addition of calcium ions to the Ca2+-regulated photoproteins, such as aequorin and obelin, produces a blue bioluminescence originating from a fluorescence transition of the protein-bound product, coelenteramide. The kinetics of several transient fluorescent species of the bound coelenteramide is resolved after picosecond-laser excitation and streak camera detection. The initially formed spectral distributions at picosecond-times are broad, evidently comprised of two contributions, one at higher energy (25000 cm-1) assigned as from the Ca2+-discharged photoprotein-bound coelenteramide in its neutral state. This component decays much more rapidly (t1/2 2 ps) in the case of the Ca2+-discharged obelin than aequorin (t1/2 30 ps). The second component at lower energy shows several intermediates in the 150-500 ps times, with a final species having spectral maxima 19400 cm-1, bound to Ca2+-discharged obelin, and 21300 cm-1, bound to Ca2+-discharged aequorin, and both have a fluorescence decay lifetime of 4 ns. It is proposed that the rapid kinetics of these fluorescence transients on the picosecond time scale, correspond to times for relaxation of the protein structural environment of the binding cavit

    The Boltzmann equation for colourless plasmons in hot QCD plasma. Semiclassical approximation

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    Within the framework of the semiclassical approximation, we derive the Boltzmann equation describing the dynamics of colorless plasmons in a hot QCD plasma. The probability of the plasmon-plasmon scattering at the leading order in the coupling constant is obtained. This probability is gauge-independent at least in the class of the covariant and temporal gauges. It is noted that the structure of the scattering kernel possesses important qualitative difference from the corresponding one in the Abelian plasma, in spite of the fact that we focused our study on the colorless soft excitations. It is shown that four-plasmon decay is suppressed by the power of gg relative to the process of nonlinear scattering of plasmons by thermal particles at the soft momentum scale. It is stated that the former process becomes important in going to the ultrasoft region of the momentum scale.Comment: 41, LaTeX, minor changes, identical to published versio

    Accurate reconstruction of insertion-deletion histories by statistical phylogenetics

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    The Multiple Sequence Alignment (MSA) is a computational abstraction that represents a partial summary either of indel history, or of structural similarity. Taking the former view (indel history), it is possible to use formal automata theory to generalize the phylogenetic likelihood framework for finite substitution models (Dayhoff's probability matrices and Felsenstein's pruning algorithm) to arbitrary-length sequences. In this paper, we report results of a simulation-based benchmark of several methods for reconstruction of indel history. The methods tested include a relatively new algorithm for statistical marginalization of MSAs that sums over a stochastically-sampled ensemble of the most probable evolutionary histories. For mammalian evolutionary parameters on several different trees, the single most likely history sampled by our algorithm appears less biased than histories reconstructed by other MSA methods. The algorithm can also be used for alignment-free inference, where the MSA is explicitly summed out of the analysis. As an illustration of our method, we discuss reconstruction of the evolutionary histories of human protein-coding genes.Comment: 28 pages, 15 figures. arXiv admin note: text overlap with arXiv:1103.434

    Influence of VEGF deprivation upon vascular formation by endothelium in the presence of macrophages

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    Development of angiogenesis depends on the functional state of endothelial cells, as well as on the balanced secretion of cytokines, growth factors and chemokines by endothelial cells and cells of microenvironment. Macrophages represent an essential component of the microenvironment and take part in the formation of blood vessels both due to the production of cytokines and due to contact interactions with endothelial cells. VEGF is among the most important cytokines that control angiogenesis at all its stages. Currently, the role of VEGF in the intercellular interactions of endothelial cells and macrophages is not well described. The aim of our study was to investigate the effect of VEGF deprivation using monoclonal antibodies on angiogenesis under conditions of co-cultivation of endothelium and macrophages. Materials and methods: monoclonal antibodies to VEGF-A were used for VEGF deprivation in monoculture of endothelial cells and in co-culture of endothelial cells with macrophages. The IL-1β, IL-6 and TNFα cytokines were used as inducers. When VEGF-A was removed from the medium, endothelial cells show plasticity and form longer vessels, they modify the expression of VEGF receptors. Macrophages regulate endothelial cell activity through the secretion of cytokines, including VEGF, and through contact interactions with endothelial cells. THP-1 cells increase the sensitivity of endothelial cells to VEGF by stimulating the VEGFR1 and VEGFR3 expression, this effect is VEGF-A-independent. The IL-1β, IL-6, TNFa cytokines independently stimulate non-branching angiogenesis, increasing the length of the vessels. At the same time, IL-ip increases the VEGFR1 expression on the surface of endothelial cells. In contrast, IL-6 and TNFα decrease it, thereby regulating the sensitivity of endothelial cells to VEGF. The effects of these cytokines are not dependent on VEGF-A. The IL-1β, IL-6, TNFα cytokines promote acquisition of anti-angiogenic properties by THP-1 cells that is independent on VEGF-A, as well as on expression of its receptors by endothelial cells. Thus, VEGF is an important, but not the sole factor controlling angiogenesis. Under conditions of VEGF-A deficiency, either endothelial cells or microenvironment cells are able to compensate for its functional load due to the production of other growth factors
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