2,003 research outputs found
Gastrointestinal tumors: Phytochemical and drug combinations targeting the hallmarks of cancer
Cancer is a worldwide burden resulting in millions of deaths each year. In particular, gastrointestinal tumors are life-threatening malignancies and one of the leading reasons for death in developed countries. Phytochemicals can be found in grains, vegetables, fruits and several foods. Many phytochemicals, such as curcumin, genistein, luteolin, vitexin-2-O-xyloside, avenanthramides, quercetin, epigallocatechin-3-gallate (EGCG), resveratrol, sulforaphane, piperine and thymoquinone have been used in combination with different chemotherapeutic agents for their synergistic anticancer effects against various forms of cancer. In this review, we describe the antitumor properties and biological effects of combinations of phytochemicals and anticancer drugs against gastrointestinal tumors: colon cancer, gastric cancer, liver cancer, pancreatic cancer. We focus on the molecular pathways, oncoproteins and tumor suppressors modulated by the combination of phytochemicals with antitumor drugs and on the biomarkers of the hallmarks of cancer influenced by these therapeutic strategies in cancer cell lines, xenograft models and clinical trials. The increased knowledge of biomarkers and molecular pathways regulated by the combination of phytochemicals and conventional anticancer drugs in both in vitro and in vivo models will remarkably improve the efficacy of these therapeutic strategies against gastrointestinal tumors in future innovative clinical applications
Involvement of pro-inflammatory cytokines and growth factors in the pathogenesis of Dupuytren's contracture: a novel target for a possible future therapeutic strategy?
Dupuytren's contracture (DC) is a benign fibro-proliferative disease of the hand causing fibrotic nodules and fascial cords which determine debilitating contracture and deformities of fingers and hands. The present study was designed to characterize pro-inflammatory cytokines and growth factors involved in the pathogenesis, progression and recurrence of this disease, in order to find novel targets for alternative therapies and strategies in controlling DC. The expression of pro-inflammatory cytokines and of growth factors was detected by immunohistochemistry in fibrotic nodules and normal palmar fascia resected respectively from patients affected by DC and carpal tunnel syndrome (CTS; as negative controls). Reverse transcription (RT)-PCR analysis and immunofluorescence were performed to quantify the expression of transforming growth factor (TGF)-β1, interleukin (IL)-1β and vascular endothelial growth factor (VEGF) by primary cultures of myofibroblasts and fibroblasts isolated from Dupuytren's nodules. Histological analysis showed high cellularity and high proliferation rate in Dupuytren's tissue, together with the presence of myofibroblastic isotypes; immunohistochemical staining for macrophages was completely negative. In addition, a strong expression of TGF-β1, IL-1β and VEGF was evident in the extracellular matrix and in the cytoplasm of fibroblasts and myofibroblasts in Dupuytren's nodular tissues, as compared with control tissues. These results were confirmed by RT-PCR and by immunofluorescence in pathological and normal primary cell cultures. These preliminary observations suggest that TGF-β1, IL-1β and VEGF may be considered potential therapeutic targets in the treatment of Dupuytren's disease (DD)
The HST Survey of BL Lac Objects: Gravitational Lens Candidates and Other Unusual Sources
We present HST observations of seven unusual objects from the HST ``snapshot
survey'' of BL Lac objects, of which four are gravitational lens candidates. In
three cases a double point sources is observed: 0033+595, with 1.58 arcsec
separation, and 0502+675 and 1440+122, each with arcsec separation.
The last two also show one or more galaxies, which could be either host or
lensing galaxies. If any are confirmed as lenses, these BL Lac objects are
excellent candidates for measuring H via gravitational time delay because
of their characteristic rapid, high amplitude variability. An additional
advantage is that, like other blazars, they are likely superluminal radio
sources, in which case the source plane is mapped out over a period of years,
providing strong additional constraints on the lensing mass distribution. The
fourth gravitational lens candidate is 1517+656, which is surrounded by three
arclets forming an almost perfect ring of radius 2.4 arcsec. If this is indeed
an Einstein ring, it is most likely a background source gravitationally lensed
by the BL Lac object host galaxy and possibly a surrounding group or cluster.
In the extreme case that all four candidates are true lenses, the derived
frequency of gravitational lensing in this BL Lac sample would be an order of
magnitude higher than in comparable quasar samples.
We also report on three other remarkable BL Lac objects: 0138-097, which is
surrounded by a large number of close companion galaxies; 0806+524, whose host
galaxy contains an uncommon arc-like structure; and 1959+650, which is hosted
by a gas rich elliptical galaxy with a prominent dust lane of .Comment: 29 pages in total, 12 figure
HST Observations of the Host Galaxies of BL Lacertae Objects
Six BL Lac objects from the complete 1 Jy radio-selected sample of 34 objects
were observed in Cycle 5 with the HST WFPC2 camera to an equivalent limiting
flux of mu_I~26 mag/arcsec^2. Here we report results for the second half of
this sample, as well as new results for the first three objects, discussed
previously by Falomo et al. (1997). In addition, we have analyzed in the same
way HST images of three X-ray-selected BL Lacs observed by Jannuzi et al.
(1997). The ensemble of 9 BL Lac objects spans the redshift range from z=0.19
to ~1. Host galaxies are clearly detected in seven cases, while the other two,
at z~0.258 (redshift highly uncertain) and z=0.997, are not resolved. The HST
images constitute a homogeneous data set with unprecedented morphological
information between a few tenths of an arcsecond and several arcseconds from
the nucleus, allowing us in 6 of the 7 detected host galaxies to rule out
definitively a pure disk light profile. The host galaxies are luminous
ellipticals with an average absolute magnitude of M_I~-24.6 mag (with
dispersion 0.7 mag), more than a magnitude brighter than L* and comparable to
brightest cluster galaxies. The morphologies are generally smooth and have
small ellipticities (epsilon<0.2). Given such roundness, there is no obvious
alignment with the more linear radio structures. In the six cases for which we
have HST WFPC2 images in two filters, the derived color profiles show no strong
spatial gradients and are as expected for K-corrected passively evolving
elliptical galaxies. The host galaxies of the radio-selected and X-ray-selected
BL Lacs for this very limited sample are comparable in both morphology and
luminosity.Comment: 23 pages, including 6 postscript figures and 3 tables (embedded).
Latex requires aaspp4.sty and psfig.sty (not included). Accepted for
publication in the Astrophysical Journa
Wide binaries as a critical test of Classical Gravity
Modified gravity scenarios where a change of regime appears at acceleration
scales have been proposed. Since for systems the
acceleration drops below at scales of around 7000 AU, a statistical
survey of wide binaries with relative velocities and separations reaching
AU and beyond should prove useful to the above debate. We apply the
proposed test to the best currently available data. Results show a constant
upper limit to the relative velocities in wide binaries which is independent of
separation for over three orders of magnitude, in analogy with galactic flat
rotation curves in the same acceleration regime. Our results are
suggestive of a breakdown of Kepler's third law beyond
scales, in accordance with generic predictions of modified gravity theories
designed not to require any dark matter at galactic scales and beyond.Comment: accepted for publication in EPJ
Pullout strength of graphene and carbon nanotube/epoxy composites
An atomistic multiscale modelling approach is used to simulate the nonlinear pullout behaviour of interlinked single walled carbon nano tubes (SWCNT) and single layer graphene sheets (SLGS) embedded in an epoxy polymer. The pullout forces have been computed for various configurations of nanocomposites (SWCNT-SWCNT, SLGS-SLGS and hybrid SLGS-SWCNT), also by evaluating the effect provided by three different interlink compounds. The interfacial strength due to fibre pullout predicted by the hybrid atomistic-FE model is compared against experimental and molecular dynamics results available in open literature. The results show the specific deformation characteristics (localised auxetics) that provide an increase of pullout forces and interfacial strength with the use of the links
A Viewing Angle - Kinetic Luminosity Unification Scheme For BL Lacertae Objects
We propose a unified classification for BL Lac objects (BLs), focusing on the
synchrotron peak frequency of the spectral energy distribution. The unification
scheme is based on the angle Theta that describes the orientation of the
relativistic jet and on the electron kinetic luminosity Lambda of the jet. We
assume that Lambda scales with the size of the jet r in a self-similar fashion
(Lambda propto r^2), as supported by observational data. The jets are
self-similar in geometry and have the same pressure and median magnetic field
at the inlet, independent of size. The self-similarity is broken for the
highest energy electrons, which radiate mainly at high frequencies, since for
large sources they suffer more severe radiative energy losses over a given
fraction of the jet length. We calculate the optically thin synchrotron
spectrum using an accelerating inner jet model based on simple relativistic gas
dynamics and show that it can fit the observed infrared to X-ray spectrum of
PKS 2155--304. We couple the accelerating jet model to the unification scheme
and compare the results to complete samples of
BLs. The negative apparent evolution of X-ray selected BLs is explained as a
result of positive evolution of the jet electron kinetic luminosity
. We review observational arguments in favor of the existence of
scaled-down accretion disks and broad emission-line regions in BLs. The
proposed unification scheme can explain the lack of observed broad emission
lines in X-ray selected BLs, as well as the existence of those lines
preferentially in luminous radio-selected BLs. Finally, we review observational
arguments that suggest the extension of this unification scheme to all blazars.Comment: 32 pages, 8 figures, to be published in the ApJ (Oct 20, 1998
Congenital malformations potentially affecting respiratory function: Multidisciplinary approach and follow-up
Background and aim. Congenital malformations such as oesophageal atresia (OA) and tracheoe-sophageal fistula (TOF), congenital pulmonary airway malformations (CPAMs), congenital diaphragmatic hernia (CDH) and vascular rings (VRs) can affect lung development and respiratory function. This observa-tional study describes our multidisciplinary approach and respiratory follow-up of children with such congenital malformations. Methods. Clinical data of children followed at the Pediatric Respiratory Unit of Parma University Hospital (Italy) between January 2015 and January 2020 were collected. Results. Twenty-three patients with congenital malformation affecting lung development were identified. Almost half of our patients were diagnosed with fetal ultrasound. Children attended the clinic at a mean age of 3 (3.7) years and follow-up visits were scheduled every 6 months average. More than half of our patients were hospitalized for lower respiratory tract infections. Six out of 9 children able to perform spirometry showed anomalies in lung function. Chest physiotherapy was recommended especially in children with OA. Conclusions. Children with congenital malformations affecting lung development are at risk of short and long-term respiratory complications, especially in the first years of life. OA was the malformation more associated to respiratory problems. Multidisciplinary approach and appropriate personalized follow-up are recommended for the best management of these children. (www.actabiomedica.it)
ROXA: a new multi-frequency selected large sample of blazars with SDSS and 2dF optical spectroscopy
Context. Although Blazars are a small fraction of the overall AGN population
they are expected to be the dominant population of extragalactic sources in the
hard X-ray and gamma-ray bands and have been shown to be the largest
contaminant of CMB fluctuation maps. So far the number of known blazars is of
the order of several hundreds, but the forthcoming AGILE, GLAST and Planck
space observatories will detect several thousand of objects of this type. Aims.
In preparation for these missions it is necessary to identify new samples of
blazars to study their multi-frequency characteristics and statistical
properties. Methods. We compiled a sample of objects with blazar-like
properties via a cross-correlation between large radio (NVSS, ATCAPMN) and X-
ray surveys (RASS) using the SDSS-DR4 and 2dF survey data to spectroscopically
identify our candidates and test the validity of the selection method. Results.
We present the Radio - Optical - X-ray catalog built at ASDC (ROXA), a list of
816 objects among which 510 are confirmed blazars. Only 19% of the candidates
turned out to be certainly non-blazars demonstrating the high efficiency of our
selection method. Conclusions. Our catalog includes 173 new blazar
identifications, or about 10% of all presently known blazars. The relatively
high flux threshold in the X-ray energy band (given by the RASS survey)
preferentially selects objects with high fx / fr ratio leading to the discovery
of new High Energy Peaked BL Lac (HBLs). Our catalog therefore includes many
new potential targets for GeV-TeV observations.Comment: 19 pages, 3 figure, 2 table
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