519 research outputs found
Correlation of Early Outcomes and Intradiscal Interleukin-6 Expression in Lumbar Fusion Patients.
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
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The Experience of Discrimination and Black-White Health Disparities in Medical Care
The current study of Black patients focuses on how discrimination contributes to racial disparities in health. The authors used a longitudinal methodology to study how perceived past discrimination affects reactions to medical interactions and adherence to physician recommendations. In addition, they explored whether these reactions and/or adherence mediate the relationship between discrimination and patients' health. The participants in this study were 156 Black patients of low socioeconomic status at a primary care clinic. Patients completed questionnaires on their current health, past adherence, and perceived past discrimination. Then, they saw a physician and rated their reactions to the visit. Four and 16 weeks later they reported on their adherence to physician recommendations and overall health. Perceived discrimination was significantly and negatively associated with patient health, reactions to the physician, and adherence. Path analyses indicated that adherence mediated the relationship between discrimination and patient health, but patient reactions to the interaction did not
PN fast winds: Temporal structure and stellar rotation
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
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 ray strength functions of Sn isotopes studied with the Oslo method
The Sn isotopes have been studied with (),
(), and () reactions to extract the nuclear
level densities (NLDs) and -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 entropy of a valence neutron
in both Sn and Sn. Moreover, the deduced microcanonical
temperatures indeed suggest a clear constant-temperature behavior above
3 MeV in Sn and above 4.5 MeV in 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 Sn
extracted in the () Coulomb excitation experiments.Comment: 13 pages, 9 figure
Microvesicles derived from leukocytes in the peripheral blood of patients with external genital endometriosis
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
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
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 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
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
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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