4,336 research outputs found
Caveolin-1 is a risk factor for postsurgery metastasis in preclinical melanoma models
Melanomas are highly lethal skin tumours that are frequently treated by surgical resection. However, the efficacy of such procedures is often limited by tumour recurrence and metastasis. Caveolin-1 (CAV1) has been attributed roles as a tumour suppressor, although in late-stage tumours, its presence is associated with enhanced metastasis. The expression of this protein in human melanoma development and particularly how the presence of CAV1 affects metastasis after surgery has not been defined. CAV1 expression in human melanocytes and melanomas increases with disease progression and is highest in metastatic melanomas. The effect of increased CAV1 expression can then be evaluated using B16F10 murine melanoma cells injected into syngenic immunocompetent C57BL/6 mice or human A375 melanoma cells injected into immunodeficient B6Rag1−/− mice. Augmented CAV1 expression suppresses tumour formation upon a subcutaneous injection, but enhances lung metastasis of cells injected into the tail vein in both models. A procedure was initially developed using B16F10 melanoma cells in C57BL/6 mice to mimic better the situation in patients undergoing surgery. Subcutaneous tumours of a defined size were removed surgically and local tumour recurrence and lung metastasis were evaluated after another 14 days. In this postsurgery setting, CAV1 presence in B16F10 melanomas favoured metastasis to the lung, although tumour suppression at the initial site was still evident. Similar results were obtained when evaluating A375 cells in B6Rag1−/− mice. These results implicate CAV1 expression in melanomas as a marker of poor prognosis for patients undergoing surgery as CAV1 expression promotes experimental lung metastasis in two different preclinical models
Robotic Wireless Sensor Networks
In this chapter, we present a literature survey of an emerging, cutting-edge,
and multi-disciplinary field of research at the intersection of Robotics and
Wireless Sensor Networks (WSN) which we refer to as Robotic Wireless Sensor
Networks (RWSN). We define a RWSN as an autonomous networked multi-robot system
that aims to achieve certain sensing goals while meeting and maintaining
certain communication performance requirements, through cooperative control,
learning and adaptation. While both of the component areas, i.e., Robotics and
WSN, are very well-known and well-explored, there exist a whole set of new
opportunities and research directions at the intersection of these two fields
which are relatively or even completely unexplored. One such example would be
the use of a set of robotic routers to set up a temporary communication path
between a sender and a receiver that uses the controlled mobility to the
advantage of packet routing. We find that there exist only a limited number of
articles to be directly categorized as RWSN related works whereas there exist a
range of articles in the robotics and the WSN literature that are also relevant
to this new field of research. To connect the dots, we first identify the core
problems and research trends related to RWSN such as connectivity,
localization, routing, and robust flow of information. Next, we classify the
existing research on RWSN as well as the relevant state-of-the-arts from
robotics and WSN community according to the problems and trends identified in
the first step. Lastly, we analyze what is missing in the existing literature,
and identify topics that require more research attention in the future
Strongly magnetized pulsars: explosive events and evolution
Well before the radio discovery of pulsars offered the first observational
confirmation for their existence (Hewish et al., 1968), it had been suggested
that neutron stars might be endowed with very strong magnetic fields of
-G (Hoyle et al., 1964; Pacini, 1967). It is because of their
magnetic fields that these otherwise small ed inert, cooling dead stars emit
radio pulses and shine in various part of the electromagnetic spectrum. But the
presence of a strong magnetic field has more subtle and sometimes dramatic
consequences: In the last decades of observations indeed, evidence mounted that
it is likely the magnetic field that makes of an isolated neutron star what it
is among the different observational manifestations in which they come. The
contribution of the magnetic field to the energy budget of the neutron star can
be comparable or even exceed the available kinetic energy. The most magnetised
neutron stars in particular, the magnetars, exhibit an amazing assortment of
explosive events, underlining the importance of their magnetic field in their
lives. In this chapter we review the recent observational and theoretical
achievements, which not only confirmed the importance of the magnetic field in
the evolution of neutron stars, but also provide a promising unification scheme
for the different observational manifestations in which they appear. We focus
on the role of their magnetic field as an energy source behind their persistent
emission, but also its critical role in explosive events.Comment: Review commissioned for publication in the White Book of
"NewCompStar" European COST Action MP1304, 43 pages, 8 figure
Characterisation of the GRAF gene promoter and its methylation in patients with acute myeloid leukaemia and myelodysplastic syndrome
We report the isolation of the 5′ flanking region of GRAF (GTPase regulator associated with the focal adhesion kinase), previously described as a putative tumour suppressor gene of acute myelogenous leukaemia and myelodysplastic syndrome, and demonstrate its promoter activity in reporter gene assays. Two putative protein-binding sites are identified of which one was sensitive to CpG methylation. The suppressed GRAF expression could be restored in leukaemia cell lines by treatment with a demethylating agent and an inhibitor of histone deacetylases. In contrast to normal tissues, which tested negative for GRAF promoter methylation, 11 of 29 (38%) bone marrow samples from patients with acute myeloid leukaemia or myelodysplastic syndrome were positive
The functioning of the Cuban home hospitalization programme: a descriptive analysis
BACKGROUND: Over the last decades hospital at home (HaH) programmes have been set up in many, mainly European, countries. The Cuban HaH programme is not hospital driven, but the responsibility of the first line health services, and family doctors play a pivotal role. METHODS: We analyse the structure and functioning of the Cuban programme. In this descriptive study, information was prospectively collected on HaH patients admitted between July 1st 2001 and June 30th 2002. RESULTS: Admission rates varied between areas from 0.014 to 0.035 per person per year (ppy). The < 1 y and 1-4 y age groups had the highest admission rates. In one area the follow-up of pregnancy problems led to high 15-24 y and 25-49 y female admission rates (0,070 and 0,058 respectively). Respiratory affections were the most frequent reason for admission (32,6%), followed by early hospital discharge (16,0%) and gynaeco-obstetrical problems (10.8%). The median length of stay varied from 5 to 7 days between regions and from 5 days (early discharge) to 7 days (gynaeco-obstetrical problems) in function of the reason for admission. On average an HaH episode entailed 1.4 and 1.6 contacts per patient-day with the family doctor and nurse respectively. CONCLUSION: Difference in admission criteria in function of geography, distance to the hospital, transport facilities, and staff factors, as well as differences in hospital policy on early discharge explain the observed variability. The programme plays an important role in the integrated approach to quality care in the Cuban health system, but could benefit from more uniform admission criteria
X-ray emission from isolated neutron stars
X-ray emission is a common feature of all varieties of isolated neutron stars
(INS) and, thanks to the advent of sensitive instruments with good
spectroscopic, timing, and imaging capabilities, X-ray observations have become
an essential tool in the study of these objects. Non-thermal X-rays from young,
energetic radio pulsars have been detected since the beginning of X-ray
astronomy, and the long-sought thermal emission from cooling neutron star's
surfaces can now be studied in detail in many pulsars spanning different ages,
magnetic fields, and, possibly, surface compositions. In addition, other
different manifestations of INS have been discovered with X-ray observations.
These new classes of high-energy sources, comprising the nearby X-ray Dim
Isolated Neutron Stars, the Central Compact Objects in supernova remnants, the
Anomalous X-ray Pulsars, and the Soft Gamma-ray Repeaters, now add up to
several tens of confirmed members, plus many candidates, and allow us to study
a variety of phenomena unobservable in "standard'' radio pulsars.Comment: Chapter to be published in the book of proceedings of the 1st Sant
Cugat Forum on Astrophysics, "ICREA Workshop on the high-energy emission from
pulsars and their systems", held in April, 201
Accurate Visuomotor Control below the Perceptual Threshold of Size Discrimination
Background: Human resolution for object size is typically determined by psychophysical methods that are based on conscious perception. In contrast, grasping of the same objects might be less conscious. It is suggested that grasping is mediated by mechanisms other than those mediating conscious perception. In this study, we compared the visual resolution for object size of the visuomotor and the perceptual system. Methodology/Principal Findings: In Experiment 1, participants discriminated the size of pairs of objects once through perceptual judgments and once by grasping movements toward the objects. Notably, the actual size differences were set below the Just Noticeable Difference (JND). We found that grasping trajectories reflected the actual size differences between the objects regardless of the JND. This pattern was observed even in trials in which the perceptual judgments were erroneous. The results of an additional control experiment showed that these findings were not confounded by task demands. Participants were not aware, therefore, that their size discrimination via grasp was veridical. Conclusions/Significance: We conclude that human resolution is not fully tapped by perceptually determined thresholds
Salt intake and gastric cancer risk according to Helicobacter pylori infection, smoking, tumour site and histological type
Background:Although salt intake is considered a probable risk factor for gastric cancer, relevant studies have provided heterogeneous results, and the magnitude of the association has not been accurately quantified.Methods:To quantify gastric cancer risk in relation to dietary salt exposure according to Helicobacter pylori infection status and virulence, smoking, tumour site, and histological type, we evaluated 422 gastric cancer cases and 649 community controls. Salt exposure was estimated in the year before the onset of symptoms through: sodium intake (estimated by a food frequency questionnaire (FFQ)); main food items/groups contributing to dietary sodium intake; visual analogical scale for salt intake preference; use of table salt; and duration of refrigerator ownership.Results:Comparing subjects with the highest with those with the lowest salt exposure (3rd vs 1st third), sodium intake (OR2.01, 95% CI: 1.16-3.46), consumption of food items with high contribution to sodium intake (OR2.54, 95% CI: 1.56-4.14) and salt intake evaluated by visual analogical scale (OR1.83, 95% CI: 1.28-2.63) were associated with an increased gastric cancer risk. Subjects owning a refrigerator for 50 years had a lower risk for gastric cancer (OR0.28, 95% CI: 0.14-0.57). These associations were observed regardless of H. pylori infection status and virulence, smoking, tumour site or histological type.Conclusion:Our results support the view that salt intake is an important dietary risk factor for gastric cancer, and confirms the evidence of no differences in risk according to H. pylori infection and virulence, smoking, tumour site and histological type. © 2011 Cancer Research UK All rights reserved.This work was performed using grants from Fundac¸ão para a Ciência e a Tecnologia (POCTI/SAU-ESP/56126/2004, POCTI/ SAU-ESP/61685/2004, PTDC/SAU-ESA/71517/2006) and Agência Portuguesa de Seguranc¸a Alimentar. This work, presented at the GRELL Meeting 2010 in Toledo, was awarded the ‘Enrico Anglesio’ Prize, offered by the ‘Anglesio Moroni Foundation’, Turin, Italy
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