450 research outputs found
Neural network parametrization of spectral functions from hadronic tau decays and determination of QCD vacuum condensates
The spectral function is determined from ALEPH and OPAL data
on hadronic tau decays using a neural network parametrization trained to retain
the full experimental information on errors, their correlations and chiral sum
rules: the DMO sum rule, the first and second Weinberg sum rules and the
electromagnetic mass splitting of the pion sum rule. Nonperturbative QCD vacuum
condensates can then be determined from finite energy sum rules. Our method
minimizes all sources of theoretical uncertainty and bias producing an estimate
of the condensates which is independent of the specific finite energy sum rule
used. The results for the central values of the condensates and are
both negative.Comment: 29 pages, 18 ps figure
Shoc2/Sur8 protein regulates neurite outgrowth
This is an openaccess
article distributed under the terms of the
Creative Commons Attribution License.-- et al.The Shoc2 protein has been implicated in the positive regulation of the Ras-ERK pathway by increasing the functional binding interaction between Ras and Raf, leading to increased ERK activity. Here we found that Shoc2 overexpression induced sustained ERK phosphorylation, notably in the case of EGF stimulation, and Shoc2 knockdown inhibited ERK activation. We demonstrate that ectopic overexpression of human Shoc2 in PC12 cells significantly promotes neurite extension in the presence of EGF, a stimulus that induces proliferation rather than differentiation in these cells. Finally, Shoc2 depletion reduces both NGF-induced neurite outgrowth and ERK activation in PC12 cells. Our data indicate that Shoc2 is essential to modulate the Ras-ERK signaling outcome in cell differentiation processes involved in neurite outgrowth.GL, TG and LMD were recipients of fellowships from the Ministerio de Educación y Ciencia (MEC) (to GL, TG), and Fondo de Investigaciones Sanitarias (FIS) (to LMD). LSR
held a postdoctoral research contract from CIBERNED. This work was supported by FIS grant
(PI10/00815) to JLO; CIBERNED to MC; SAF2008-01951, Comunidad Autónoma de Madrid (CAM) SSAL-0202-2006-01 and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) to TI; FIS grant PI12/00775 and ISCIII-RETIC (Red Temática de Investigación Cooperativa en Cáncer) RD12/0036/0027 from the Instituto de Salud Carlos III to PSG; and FIS grants (PI09/0562 and PI13/00703), ISCIIIRETIC
(RD06/0020/0003 and RD12/0036/0021), and the Spanish Association Against Cancer
(AECC) to JMR.Peer Reviewe
Von Hippel-Lindau protein is required for optimal alveolar macrophage terminal differentiation, self-renewal, and function
The rapid transit from hypoxia to normoxia in the lung that follows the first breath in newborn mice coincides with alveolar macrophage (AM) differentiation. However, whether sensing of oxygen affects AM maturation and function has not been previously explored. We have generated mice whose AMs show a deficient ability to sense oxygen after birth by deleting Vhl, a negative regulator of HIF transcription factors, in the CD11c compartment (CD11c Delta Vhl mice). VHL-deficient AMs show an immature-like phenotype and an impaired self-renewal capacity in vivo that persists upon culture ex vivo. VHL-deficient phenotype is intrinsic in AMs derived from monocyte precursors in mixed bone marrow chimeras. Moreover, unlike control Vhl(fl/fl), AMs from CD11c Delta Vhl mice do not reverse pulmonary alveolar proteinosis when transplanted into Csf2rb(-/)(-) mice, demonstrating that VHL contributes to AM-mediated surfactant clearance. Thus, our results suggest that optimal AM terminal differentiation, self-renewal, and homeostatic function requires their intact oxygen-sensing capacity
Promoter hypermethylation of cancer-related genes: a strong independent prognostic factor in acute lymphoblastic leukemia
Promoter hypermethylation plays an important
role in the inactivation of cancerrelated
genes. This abnormality occurs
early in leukemogenesis and seems to be
associated with poor prognosis in acute
lymphoblastic leukemia (ALL). To determine
the extent of hypermethylation in
ALL, we analyzed the methylation status
of the CDH1, p73, p16, p15, p57, NES-1,
DKK-3, CDH13, p14, TMS-1, APAF-1,
DAPK, PARKIN, LATS-1, and PTEN genes
in 251 consecutive ALL patients.Atotal of
77.3% of samples had at least 1 gene
methylated, whereas 35.9% of cases had
4 or more genes methylated. Clinical features
and complete remission rate did not
differ among patients without methylated
genes, patients with 1 to 3 methylated
genes (methylated group A), or patients
with more than 3 methylated genes (methylated
group B). Estimated disease-free
survival (DFS) and overall survival (OS) at
11 years were 75.5% and 66.1%, respectively,
for the nonmethylated group; 37.2%
and 45.5% for methylated group A; and
9.4% and 7.8% for methylated group B
(P < .0001 and P .0004, respectively).
Multivariate analysis demonstrated that
the methylation profile was an independent
prognostic factor in predicting DFS
(P < .0001) and OS (P .003). Our results
suggest that the methylation profile may
be a potential new biomarker of risk prediction
in AL
Modelling the nova rate in galaxies
We compute theoretical nova rates as well as type Ia SN rates in galaxies of
different morphological type (Milky Way, ellipticals and irregulars) by means
of detailed chemical evolution models, and compare them with the most recent
observations. The main difference among the different galaxies is the assumed
history of star formation. In particular, we predict that the nova rates in
giant ellipticals such as M87 are 100-300 nova/yr, about a factor of ten larger
than in our Galaxy (25 nova/yr), in agreement with very recent estimates from
HST data. The best agreement with the observed rates is obtained if the
recurrence time of novae in ellipticals is assumed to be longer than in the
Milky Way. This result indicates that the star formation rate in ellipticals,
and in particular in M87, must have been very efficient at early cosmic epochs.
We predict a nova rate for the LMC of 1.7 nova/yr, again in agreement with
observations. We compute also the K- and B-band luminosities for ellipticals of
different luminous mass and conclude that there is not a clear trend for the
luminosity specific nova rate with luminosity among these galaxies. However,
firm conclusions about ellipticals cannot be drawn because of possible
observational biases in observing these objects. The comparison between the
specific nova rates in the Milky Way and the LMC indicates a trend of
increasing nova rate passing from the Galaxy towards late-type spirals and
Magellanic irregulars.Comment: 9 pages, 5 figures, Astronomy and Astrophysics accepte
The VIL gene CRAWLING ELEPHANT controls maturation and differentiation in tomato via polycomb silencing
VERNALIZATION INSENSITIVE 3-LIKE (VIL) proteins are PHD-finger proteins that recruit
the repressor complex Polycomb Repressive Complex 2 (PRC2) to the promoters of target
genes. Most known VIL targets are flowering repressor genes. Here, we show that the
tomato VIL gene CRAWLING ELEPHANT (CREL) promotes differentiation throughout plant
development by facilitating the trimethylation of Histone H3 on lysine 27 (H3K27me3). We
identified the crel mutant in a screen for suppressors of the simple-leaf phenotype of entire
(e), a mutant in the AUX/IAA gene ENTIRE/SlIAA9, involved in compound-leaf development
in tomato. crel mutants have increased leaf complexity, and suppress the ectopic blade
growth of e mutants. In addition, crel mutants are late flowering, and have delayed and aber rant stem, root and flower development. Consistent with a role for CREL in recruiting PRC2,
crel mutants show drastically reduced H3K27me3 enrichment at approximately half of the
14,789 sites enriched in wild-type plants, along with upregulation of many underlying genes.
Interestingly, this reduction in H3K27me3 across the genome in crel is also associated with
gains in H3K27me3 at a smaller number of sites that normally have modest levels of the
mark in wild-type plants, suggesting that PRC2 activity is no longer limiting in the absence of
CREL. Our results uncover a wide role for CREL in plant and organ differentiation in tomato
and suggest that CREL is required for targeting PRC2 activity to, and thus silencing, a spe cific subset of polycomb targets
Factors associated with excessive bleeding in cardiopulmonary bypass patients: a nested case-control study
<p>Abstract</p> <p>Introduction</p> <p>Excessive bleeding (EB) after cardiopulmonary bypass (CPB) may lead to increased mortality, morbidity, transfusion requirements and re-intervention. Less than 50% of patients undergoing re-intervention exhibit surgical sources of bleeding. We studied clinical and genetic factors associated with EB.</p> <p>Methods</p> <p>We performed a nested case-control study of 26 patients who did not receive antifibrinolytic prophylaxis. Variables were collected preoperatively, at intensive care unit (ICU) admission, at 4 and 24 hours post-CPB. EB was defined as 24-hour blood loss of >1 l post-CPB. Associations of EB with genetic, demographic, and clinical factors were analyzed, using SPSS-12.2 for statistical purposes.</p> <p>Results</p> <p>EB incidence was 50%, associated with body mass index (BMI)< 26.4 (25–28) Kg/m<sup>2</sup>, (<it>P </it>= 0.03), lower preoperative levels of plasminogen activator inhibitor-1 (PAI-1) (<it>P </it>= 0.01), lower body temperature during CPB (<it>P </it>= 0.037) and at ICU admission (<it>P </it>= 0.029), and internal mammary artery graft (<it>P </it>= 0.03) in bypass surgery. We found a significant association between EB and 5G homozygotes for PAI-1, after adjusting for BMI (F = 6.07; <it>P </it>= 0.02) and temperature during CPB (F = 8.84; <it>P </it>= 0.007). EB patients showed higher consumption of complement, coagulation, fibrinolysis and hemoderivatives, with significantly lower leptin levels at all postoperative time points (<it>P </it>= 0.01, <it>P </it>< 0.01 and <it>P </it>< 0.01).</p> <p>Conclusion</p> <p>Excessive postoperative bleeding in CPB patients was associated with demographics, particularly less pronounced BMI, and surgical factors together with serine protease activation.</p
BCR-ABL1-induced expression of HSPA8 promotes cell survival in chronic myeloid leukaemia
In order to determine new signal transduction pathways implicated in
chronic myeloid leukaemia (CML), we performed a gene expression profile
comparison between CD34+ cells from CML patients and healthy donors.
Functional studies were performed using the Mo7e and Mo7e-p210 cell lines.
Expression of CCND1 (Cyclin D1), as well as the chaperone HSPA8, which is
important for regulation of CCND1, were significantly upregulated in CD34+
CML cells. Upregulation of HSPA8 was dependent, at least in part, on STAT5
(signal transducer and activator of transcrition 5)-dependent transcriptional
activation, as demonstrated by chromatin immunoprecipitation. The
presence of HSPA8 in the nuclear protein fraction as well as its binding to
CCND1 suggests that it may contribute to stabilization of the CCND1/CDK4
complex, which, in turn, may participate in proliferation of CML
cells. Treatment of CML cells with the specific HSPA8 inhibitor
15-deoxyspergualin induced inhibition of CML cell viability but did not
induce apoptosis. In conclusion, our studies suggest that STAT5-mediated
activation of HSPA8 induces nuclear translocation and activation of the
CCND1/CDK4 complex leading to increased proliferation of CML cells,
deciphering a new pathway implicated in CML and supporting a potential
role of chaperone inhibitors in the treatment of CML
Evolución paleoambiental de la mitad sur de la Península Ibérica. Aplicación a la evaluación del comportamiento de los repositorios de residuos radiactivos
Esta publicación refleja los resultados obtenidos de la realización de los proyectos "EQUIP: Evidency from Quaternary Infills Palaeohydrogeology" (F 14W/ CT96/0031), financiado por la UE, "Evolución Paleoclimática de [a Mitad Sur de [a Península Ibérica" financiado por ENRESA y "Paleoclima" financiado por el Consejo de Seguridad Nuclear y ENRESA. La cuenca de Guadix-Baza, sector oriental, es una de las escasas zonas europeas donde se ha conservado un registro razonablemente completo del Pleistoceno. La cuenca de Guadix Baza, en régimen continental desde el Plioceno, funcionó bajo un régimen centrípeto, con abanicos aluviales en los bordes y una zona compleja lacustre en mosaico en su centro. Se ha podido establecer la existencia de una amplia variedad de facies aluviales y fluviales y sus interrelaciones. La sedimentación en el margen lacustre estaba constituida por arenas bioclásticas y lutitas con fósiles, mientras que en zonas más centrales predominaron lutitas yesíferas, lutitas con yeso intrasedimentario, arenas yesíferas yesos y, ocasionalmente, carbonatos que durante un período concreto depositaron los materiales que configuran el "Nivel Calcáreo de Orce", calizas y dolomías con cantidades variables de yeso y terrígenos cerca de los bordes. El trabajo de campo permitió el establecimiento de una serie estratigráfica tipo compuesta, que refleja los principales acontecimiento paleoambientales que tuvieron lugar durante el Pleistoceno. Con el fin de evitar la yesificación de la calcita y aragonito, propia del ambiente lacustre, la serie tipo de ha establecido en el registro del margen lacustre. Con ayuda del análisis paleomagnético y el análisis de la racemización de aminoácidos en conchas de moluscos y ostrácodos se ha establecido la cronología numérica de la sección estratigráfica tipo que cubre desde el límite Plioceno-Pleistoceno hasta unos 250 ka BP, cuando la erosión de la cabecera del río Fardes alcanza la cuenca abriéndola hacia el valle del Guadalquivir y cesando [a sedimentación lacustre. También se ha datado un depósito de terraza fluvial. Se han obtenido datos paleoambientales "instantáneos" mediante el estudio palinológico, el análisis paleobotánico de material silicificado (madera opalizada) o carbonizado (análisis paleoantracológico), el análisis geoquímico orgánico de algunos niveles especialmente favorables. La geoquímica orgánica de biomarcadores de algunos niveles concretos proporcionó datos sobre su origen (plantas terrestres o acuáticas) y confirmó que un conspicuo nivel carbonoso tuvo su origen en un incendio forestal. El análisis paleobiológico basado en la distribución de especies de ostrácodos, gasterópodos y pelecípodos ha permitido una primera aproximación paleoambiental, pese al evidente sesgo introducido por la presencia de fuentes salinas y materiales yesíferos en el área fuente de los abanicos aluviales del límite oriental de la cuenca. Esta interpretación se ha depurado mediante el estudio geoquímico inorgánico, isótopos estables y elementos traza de las conchas calcíticas de ostrácodos. Ello ha permitido el establecimiento de una alternancia de períodos "fríos y húmedos" y "cálidos y áridos" que permiten reconocer de las clases climáticas "mediterráneo seco" y "mediterráneo húmedo" sensu Horowitz (1989), que tienen sus correlatos en el registro paleoclimático de los grandes lagos del rift del Mar Muerto, el Mar Caspio y lagos pluviales de Norte América. La correlación de los datos isotópicos con las paleosalinidades deducidas del estudio de las inclusiones fluidas en yeso intrasedimentario ha permitido corroborar estas interpretaciones. Esto plantea un nuevo enfoque en el análisis del comportamiento de los repositorios de residuos radiactivos de alta
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