630 research outputs found
Regulation of macrophage and granulocyte proliferation. Specificities of prostaglandin E and lactoferrin
Hemopoietic colony-forming cells committed to macrophage differentiation (M-CFC) are selectively and differentially inhibited by prostaglandin E (PGE). A hierarchy of sensitivity was observed among murine CFC stimulated by colony-stimulating factors (CSF) which differ in their ability to initiate proliferation of morphologically distinct colony types, or stimulated by CSF provided by macrophage feeder layers. Inhibition of macrophage colony formation to 50 percent levels occurred with PGE concentrations between 10(-8) and 10(-9) M, and was still evident at 10(-10) -10(-11) M PGE concentrations. The growth of mixed colonies containing both macrophages and neutrophils was less sensitive to the inhibitory effects of PGE, however, the monocytoid component of these colonies was reduced in the presence of PGE. Neutrophil progenitor cell proliferation was not influenced by PGE concentrations below 10(-6) M, regardless of time of addition of PGE, whereas clonal macrophage expansion, as well as clone size, was sensitive to inhibition by PGE when added as late as 3 d after culture initiation. Prostaglandin F(2α), was not inhibitory to colony formation. Experimental evidence for a selective role of macrophage PGE in the regulation of macrophage colony formation was directly provided by utilizing resident peritoneal macrophages as a source of CSF for bone marrow target cell overlays. Simultaneous morphological analysis of colonies proliferating in bilayer culture in response to increasing concentrations of macrophages, and direct measurements of PGE synthesized by an identical number of macrophages maintained in liquid culture demonstrate that a specific decline in macrophage colony formation occurs coincident with a linear increase in macrophage PGE synthesis. Inhibition of macrophage PGE synthesis by indomethacin results in the specific enhancement of macrophage colony formation. Furthermore, macrophage PGE synthesis is induced by CSF preparations with the selective capacity to differentially stimulate macrophage proliferation, but not by those which preferentially stimulate granulocyte colony formation. In comparison to the effects of PGE on M-CFC, polymorphonuclear granulocyte-derived lactoferrin (LF) reduces macrophage production of colony-stimulating activities for macrophage, mixed macrophage- neutrophil and neutrophil colony formation. The ability of LF to reduce macrophage PGE synthesis, presumably by decreasing CSF production, suggests that LF and PGE can interact in the control of macrophage and granulocyte proliferation
N=2 supersymmetric gauge theories with massive hypermultiplets and the Whitham hierarchy
We embed the Seiberg-Witten solution for the low energy dynamics of N=2 super
Yang-Mills theory with an even number of massive hypermultiplets into the
Whitham hierarchy. Expressions for the first and second derivatives of the
prepotential in terms of the Riemann theta function are provided which extend
previous results obtained by Gorsky, Marshakov, Mironov and Morozov. Checks in
favour of the new equations involve both their behaviour under duality
transformations and the consistency of their semiclassical expansions.Comment: 37 pages, LaTeX2e, no figures; references adde
Instanton corrections in N=2 supersymmetric theories with classical gauge groups and fundamental matter hypermultiplets
We compute instanton corrections to the low energy effective prepotential of
N=2 supersymmetric theories in a variety of cases, including all classical
gauge groups and even number of fundamental matter hypermultiplets. To this
end, we take profit of a set of first- and second-order equations for the
logarithmic derivatives of the prepotential with respect to the dynamical scale
expressed in terms of Riemann's theta-function. These equations emerge in the
context of the Whitham hierarchy approach to the low-energy Seiberg--Witten
solution of supersymmetric gauge theories. Our procedure is recursive and
allows to compute the effective prepotential to arbitrary order in a remarkably
straightforward way. General expressions for up to three-instanton corrections
are given. We illustrate the method with explicit expressions for several
cases.Comment: 25 pages, LaTeX2e, no figures; v2: Concluding remarks expanded, other
minor changes. Final version to be published in Nuclear Physics
Pregabalin in fibromyalgia - responder analysis from individual patient data
<p>Abstract</p> <p>Background</p> <p>Population mean changes are difficult to use in clinical practice. Responder analysis may be better, but needs validating for level of response and treatment duration. A consensus group has defined what constitutes minimal, moderate, and substantial benefit based on pain intensity and Patient Global Impression of Change scores.</p> <p>Methods</p> <p>We obtained individual patient data from four randomised double blind trials of pregabalin in fibromyalgia lasting eight to 14 weeks. We calculated response for all efficacy outcomes using any improvement (≥ 0%), minimal improvement (≥ 15%), moderate improvement (≥ 30%), substantial improvement (≥ 50%), and extensive improvement (≥ 70%), with numbers needed to treat (NNT) for pregabalin 300 mg, 450 mg, and 600 mg daily compared with placebo.</p> <p>Results</p> <p>Information from 2,757 patients was available. Pain intensity and sleep interference showed reductions with increasing level of response, a significant difference between pregabalin and placebo, and a trend towards lower (better) NNTs at higher doses. Maximum response rates occurred at 4-6 weeks for higher levels of response, and were constant thereafter. NNTs (with 95% confidence intervals) for ≥ 50% improvement in pain intensity compared with placebo after 12 weeks were 22 (11 to 870) for pregabalin 300 mg, 16 (9.3 to 59) for pregabalin 450 mg, and 13 (8.1 to 31) for pregabalin 600 mg daily. NNTs for ≥ 50% improvement in sleep interference compared with placebo after 12 weeks were 13 (8.2 to 30) for pregabalin 300 mg, 8.4 (6.0 to 14) for pregabalin 450 mg, and 8.4 (6.1 to 14) for pregabalin 600 mg. Other outcomes had fewer respondents at higher response levels, but generally did not discriminate between pregabalin and placebo, or show any dose response. Shorter duration and use of 'any improvement' over-estimated treatment effect compared with longer duration and higher levels of response.</p> <p>Conclusions</p> <p>Responder analysis is useful in fibromyalgia, particularly for pain and sleep outcomes. Some fibromyalgia patients treated with pregabalin experience a moderate or substantial pain response that is consistent over time. Short trials using 'any improvement' as an outcome overestimate treatment effects.</p
Search for blue compact dwarf galaxies during quiescence II: metallicities of gas and stars, ages, and star-formation rates
We examine the metallicity and age of a large set of SDSS/DR6 galaxies that
may be Blue Compact Dwarf (BCD) galaxies during quiescence (QBCDs).The
individual spectra are first classified and then averaged to reduce noise. The
metallicity inferred from emission lines (tracing ionized gas) exceeds by ~0.35
dex the metallicity inferred from absorption lines (tracing stars). Such a
small difference is significant according to our error budget estimate. The
same procedure was applied to a reference sample of BCDs, and in this case the
two metallicities agree, being also consistent with the stellar metallicity in
QBCDs. Chemical evolution models indicate that the gas metallicity of QBCDs is
too high to be representative of the galaxy as a whole, but it can represent a
small fraction of the galactic gas, self enriched by previous starbursts. The
luminosity weighted stellar age of QBCDs spans the whole range between 1 and 10
Gyr, whereas it is always smaller than 1 Gyr for BCDs. Our stellar ages and
metallicities rely on a single stellar population spectrum fitting procedure,
which we have specifically developed for this work using the stellar library
MILES.Comment: Accepted for publication in ApJ. 20 pages. 16 figures (corrected
typos
Clayey materials from the Sierra de la Demanda Range (Spain): their potential as raw materials for the building ceramics industry
This work describes the possible use of thick Early Cretaceous clay deposits, which
occur in the southern sector of the Sierra de la Demanda range, as raw materials in the manufacture
of ceramic articles. The global mineralogical composition is characterized by high proportions of
phyllosilicates and quartz with variable quantities of feldspars, carbonates and hematite. The clay
mineralogy differentiates two types of raw materials: illitic clay and kaolinitic-illitic clay. A
granulometric distribution in the 2ÿ60 mm fraction, good behaviour during the drying stage and
acceptable results in firing tests confirmed that most samples can be utilized as raw material in the
building ceramics industry. The range of suitable firing temperatures for these materials is
950ÿ1000ëC, a temperature which needs to be raised for samples with a high percentage of kaolinite
and quartz. Moreover, other materials with abundant calcite (20ÿ30%) are suitable for use as
modifiers of some properties or colour
Probes on D3-D7 Quark-Gluon Plasmas
We study the holographic dual model of quenched flavors immersed in a
quark-gluon plasma with massless dynamical quarks in the Veneziano limit. This
is modeled by embedding a probe D7 brane in a background where the backreaction
of massless D7 branes has been taken into account. The background, and hence
the effects, are perturbative in the Veneziano parameter N_f/N_c, therefore
giving small shifts of all magnitudes like the constituent mass, the quark
condensate, and several transport coefficients. We provide qualitative results
for the effect of flavor degrees of freedom on the probes. For example, the
meson melting temperature is enhanced, while the screening length is
diminished. The drag force is also enhanced.Comment: 31 pages, 17 figure
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