1,955 research outputs found
Omeprazole induces apoptosis in normal human polymorphonuclear leucocytes.
We investigated in vitro apoptosis in human polymorphonuclear neutrophils (PMN) induced by omeprazole. This drug, both in the native (OM) and acidified (OM-HCl) form, is a potent inducer of PMN apoptosis. The effect is time- and dose-dependent. OM-HCl is more efficient than OM in inducing PMN apoptosis. In fact, after 24 h incubation in vitro at 1Ă10 â4M OM-HCl induces apoptosis in 70% of the cell population compared to 37% induced by OM. Apoptosis induced by both forms of the drug is caspase dependent being significantly reduced by pretreating cells with the caspase 3 inhibitor (DEVDH-CHO). However, some differences in the apoptosis mechanisms between the two forms of the drug seem to exist because PMN treatment with the specific caspase 8 inhibitor (Z-IETD-FMK) only blocks OM-HCl mediated apoptosis. We observed cleavage of caspase 8 only in the cells incubated with OM-HCl while the executioner caspase 3 was activated with both forms of the drug. Furthermore, pretreatment with GM-CSF, a known activator of intracellular survival pathways in PMN, partially protected cells from OM-HCl induced apoptosis but did not contrast the apoptotic effect of OM. Cysteine cathepsin proteases also seem involved in the apoptotic mechanism of both drug forms since the specific inhibitor E64d gave a significant protection. To verify if OM-HCl induced apoptosis was dependent on the sulfenamide bound with the cell sulfhydryl groups we used molecules with thiol groups such as ÎČ-mercaptoethanol (ÎČ-ME) and reduced glutathione (GSH). Reactions of OM-HCl with cellular sulfhydryl groups are strongly involved in both the triggering and evolving phase of the apoptotic mechanism since significant protection from apoptosis was obtained when PMN were pretreated for 1h with ÎČ-ME (lipid-permeable) or GSH (lipid-impermeable). These results show that OM and OM-HCl induce apoptosis in human PMN and suggest that the second binds the sulfhydryl groups, present on the cell membrane, to then penetrate the cell thus causing a further significant increase in apoptosis. OM-induced PMN apoptosis during the treatment of gastric inflammatory disease could be an advantage for the resolution of the phlogosis state. However, this aspect should be further elucidated to assess the optimal therapeutical regimen for gastric diseases which are related to infective agents
Le parole sono ponti: risorse digitali per l'integrazione in contesti multilingui
Learning the language of the hosting country is a key factor for the integration
of people coming from abroad but this objective could be achieved only if political
institutions promote initiatives in this direction. Researchers in the field
can cooperate, providing their expertise. In this paper we present two research
activities concerning the use and the production of multilingual resources
developed at the Institute for Computational Linguistics âAntonio Zampolliâ.
More specifically, we report on the creation of a multilingual glossary of difficult
terms extracted from forms that people submit to the municipality of
Genova to access public services. We also describe the experimental use in a
primary school of ImagAct, a multilingual lexical resource focused on action
verbs consulted by pupils to create a vocabulary of food preparation in Italian,
English, Chinese and Spanish
Gly482Ser PGC-1α gene polymorphism and exercise-related oxidative stress in amyotrophic lateral sclerosis patients
The role of exercise in Amyotrophic lateral sclerosis (ALS) pathogenesis is controversial and unclear. Exercise induces a pleiotropic adaptive response in skeletal muscle, largely through the peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a transcriptional coactivator that regulates mitochondrial biogenesis and antioxidant defense mechanisms. It has been suggested that a Gly482Ser substitution in PGC-1α has functional relevance in human disorders and in athletic performance. To test this hypothesis, we examined the genotype distribution of PGC-1α Gly482Ser (1444 G > A) in ALS patients to evaluate whether or not the minor serine-encoding allele 482Ser is involved in oxidative stress responses during physical exercise. We genotyped 197 sporadic ALS patients and 197 healthy controls in order to detect differences in allelic frequencies and genotype distribution between the two groups. A total of 74 ALS patients and 65 controls were then comparatively assessed for plasmatic levels of the oxidative stress biomarkers, advanced oxidation protein products, ferric reducing ability and thiol groups. In addition a subgroup of 35 ALS patients were also assessed for total SOD and catalase plasmatic activity. Finally in 28 ALS patients we evaluated the plasmatic curve of the oxidative stress biomarkers and lactate during an incremental exercise test. No significant differences were observed in the genotype distribution and allelic frequency in ALS patients compared to the controls. We found significant increased advanced oxidation protein products (p A SNP, ALS patients with Gly482Ser allelic variant show increased exercise-related oxidative stress. This thus highlights the possible role of this antioxidant defense transcriptional coactivator in ALS
The dependence of AGN activity on stellar and halo mass in Semi-Analytic Models
AGN feedback is believed to play an important role in shaping a variety of
observed galaxy properties, as well as the evolution of their stellar masses
and star formation rates. In particular, in the current theoretical paradigm of
galaxy formation, AGN feedback is believed to play a crucial role in regulating
the levels of activity in galaxies, in relatively massive halos at low
redshift. Only in recent years, however, has detailed statistical information
on the dependence of galaxy activity on stellar mass, parent halo mass and
hierarchy has become available. In this paper, we compare the fractions of
galaxies belonging to different activity classes (star-forming, AGN and radio
active) with predictions from four different and independently developed
semi-analytical models. We adopt empirical relations to convert physical
properties into observables (H_alpha emission lines, OIII line strength and
radio power). We demonstrate that all models used in this study reproduce the
overall distributions of galaxies belonging to different activity classes as a
function of stellar mass and halo mass: star forming galaxies and the strongest
radio sources are preferentially associated with low-mass and high-mass
galaxies/halos respectively. However, model predictions differ from
observational measurements in a number of ways. All models used in our study
predict that almost every >1.e12 Msun dark matter halo and/or >1.e11 Msun
galaxy should host a bright radio source, while only a small fraction of
galaxies belong to this class in the data. In addition, radio brightness is
expected to depend strongly on the mass of the parent halo mass in the models,
while strong and weak radio galaxies are found in similar environments in data.
Our results highlight that the distribution of AGN as a function of stellar
mass provides one of the most promising discriminants between different gas
accretion schemes.Comment: 15 pages; 8 figures; 1 table; updated to match MNRAS accepted versio
Narcisos insubmissos: autorrepresentação, identidade e diferença nas artes visuais ibero-americanas
Diante da compreensĂŁo de que compartilhamos um passado histĂłrico e sociocultural recente e similar (semiperifĂ©rico, ditatorial, colonial, cristĂŁo, monoteĂsta patriarcal), o que as artes ibero-americanas teriam a dizer sobre as ficçÔes dominantes e com que ferramentas estĂ©ticas e dissensuais fariam frente a um consenso policialesco de gĂȘnero, sexualidade, raça e classe social? Que cenas, gestos e rostos, mesmo que transitĂłrios, ambĂguos e relacionais, poderiam perturbar determinados regimes policialescos nĂŁo apenas de raça, gĂȘnero e classe, mas tambĂ©m perturbar as prĂłprias ficçÔes dominantes no campo das artes?
Com este nĂșmero, pretendemos analisar entĂŁo as operaçÔes discursivas e estĂ©ticas que ocorrem quando sĂŁo as subjetividades subalternas que representam a si mesmas, em vez de serem retratadas a partir do olhar de um Outro hegemĂŽnico que frequentemente procura coisificĂĄ-las, dominĂĄ-las e observĂĄ-las de uma distĂąncia que nĂŁo contamine sua subjetividade
Evolution of environment dependent galaxy properties in the Sloan Digital Sky Survey
We use photometric redshifts to analyse the effect of local environment on
galaxy colours at redshifts z < 0.63 in the SDSS data release 6. We construct
mock SDSS-DR6 catalogues using semi-analytic galaxies to study possible
systematic effects on the characterisation of environment and colour statistics
due to the uncertainty in the determination of redshifts. We use the projected
galaxy density derived from the distance to the nearest neighbours with a
suitable radial velocity threshold to take into account the uncertainties in
the photometric redshift estimates. Our findings indicate that the use of
photometric redshifts greatly improves estimates of projected local galaxy
density when galaxy spectra are not available. We find a tight relationship
between spectroscopic and photometric derived densities, both in the SDSS-DR6
data (up to z=0.3) and mock catalogues (up to z=0.63).
At z=0, faint galaxies show a clear increase of the red galaxy fraction as
the local density increases. Bright galaxies, on the other hand, show a
constant red galaxy fraction. We are able to track the evolution of this
fraction to z=0.55 for galaxies brighter than M_r=-21.5 and find that the
fraction of blue galaxies with respect to the total population progressively
becomes higher as the redshift increases, at a rate of 15% Gyr. Also, at any
given redshift, bright galaxies show a larger red population, indicating that
the star-formation activity shifts towards smaller objects as the redshift
decreases.Comment: 9 pages, 6 figures. Accepted by MNRA
Modeling the cosmological co-evolution of supermassive black holes and galaxies: II. The clustering of quasars and their dark environment
We use semi-analytic modeling on top of the Millennium simulation to study
the joint formation of galaxies and their embedded supermassive black holes.
Our goal is to test scenarios in which black hole accretion and quasar
activity are triggered by galaxy mergers, and to constrain different models for
the lightcurves associated with individual quasar events. In the present work
we focus on studying the spatial distribution of simulated quasars. At all
luminosities, we find that the simulated quasar two-point correlation function
is fit well by a single power-law in the range 0.5 < r < 20 h^{-1} Mpc, but its
normalization is a strong function of redshift. When we select only quasars
with luminosities within the range typically accessible by today's quasar
surveys, their clustering strength depends only weakly on luminosity, in
agreement with observations. This holds independently of the assumed lightcurve
model, since bright quasars are black holes accreting close to the Eddington
limit, and are hosted by dark matter haloes with a narrow mass range of a few
10^12 h^{-1} M_sun. Therefore the clustering of bright quasars cannot be used
to disentangle lightcurve models, but such a discrimination would become
possible if the observational samples can be pushed to significantly fainter
limits.
Overall, our clustering results for the simulated quasar population agree
rather well with observations, lending support to the conjecture that galaxy
mergers could be the main physical process responsible for triggering black
hole accretion and quasar activity.Comment: 17 pages, 16 figures, to be published on MNRA
Extending the M_(bh)-sigma diagram with dense nuclear star clusters
Abridged: Four new nuclear star cluster masses, M_nc, plus seven upper
limits, are provided for galaxies with previously determined black hole masses,
M_bh. Together with a sample of 64 galaxies with direct M_bh measurements, 13
of which additionally now have M_nc measurements rather than only upper limits,
plus an additional 29 dwarf galaxies with available M_nc measurements and
velocity dispersions sigma, an (M_bh + M_nc)-sigma diagram is constructed.
Given that major dry galaxy merger events preserve the M_bh/L ratio, and given
that L ~ sigma^5 for luminous galaxies, it is first noted that the observation
M_bh ~ sigma^5 is consistent with expectations. For the fainter elliptical
galaxies it is known that L ~ sigma^2, and assuming a constant M_nc/L ratio
(Ferrarese et al.), the expectation that M_nc ~ sigma^2 is in broad agreement
with our new observational result that M_nc ~ sigma^{1.57\pm0.24}. This
exponent is however in contrast to the value of ~4 which has been reported
previously and interpreted in terms of a regulating feedback mechanism from
stellar winds.Comment: 6 pages, 2 figures. Submitted 08/08/2011 to MNRAS, first referee
report received 19/01/2012, accepted 10/02/201
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