Targets for the Treatment of Breast Cancer

The completion of the human genome sequence provides unique opportunities to identify new molecular targets for a variety of diseased conditions, especially for neoplastic diseases. Breast cancer is an ideal disease for the implementation of the recently developed, sophisticated genomic technologies, which permit the study of expression of many genes or proteins simultaneously, an approach known as molecular profiling. This approach is considered a major step forward in the development of new drugs that are more effective and less toxic than the current generation of antitumor agents. In this paper, we briefly review the current and future genomics technologies, such as DNA microarrays and proteomics techniques, and their use in the identification of new molecular targets for the treatment of breast cancer. We also discuss the challenge associated with the development of bioinformatics tools to analyze the massive number of data points generated by these technologies. Proof of principle is now emerging, demonstrating that selective agents against abnormal or mutated gene products can indeed be useful in the treatment of cancer. However, despite heavy investment in genomics research by the pharmaceutical industry, the full impact of genomics on drug discovery has yet to be fully demonstrated

CoRoT observations of O stars: diverse origins of variability

Six O-type stars were observed continuously by the CoRoT satellite during a 34.3-day run. The unprecedented quality of the data allows us to detect even low-amplitude stellar pulsations in some of these stars (HD 46202 and the binaries HD 46149 and Plaskett's star). These cover both opacity-driven modes and solar-like stochastic oscillations, both of importance to the asteroseismological modelling of O stars. Additional effects can be seen in the CoRoT light curves, such as binarity and rotational modulation. Some of the hottest O-type stars (HD 46223, HD 46150 and HD 46966) are dominated by the presence of red-noise: we speculate that this is related to a sub-surface convection zone.Comment: 5 pages, 3 figures, conference paper. To be published in "Four decades of Research on Massive Stars", Astronomical Society of the Pacific. Eds. C. Robert, N. St-Louis and L. Drisse

The potential impact of banana Xanthomonas wilt on food systems in Africa: modeling scenarios of policy response and disease control measures

Banana Xanthomonas wilt (BXW) is one of the most important diseases threatening banana production in Africa south of the Sahara (SSA). In this study, we examine the potential impacts of BXW on banana production, demand, and food security in SSA, if the disease spread across all banana-producing countries in the region. The analysis is based on a multidisciplinary approach that combines a mathematical model of field-level BXW spread over time with a dynamic global partial equilibrium economic model. Since BXW control relies exclusively on management, we analyze three scenarios of BXW spread that are constructed around assumptions about the level of policy response to the disease, and about how this response may affect the adoption of appropriate management practices by farmers to control BXW. Modeling results suggest that if the disease is left uncontrolled, banana production in SSA within 10 years can decrease by as much as 55%, compared to a BXW-free baseline scenario, resulting in economic losses of around 25 billion USD. At the same time, the population at risk of hunger in countries that highly depend on bananas as a staple food is projected to increase by more than 4.6%. Even a limited policy response to BXW can reduce infections and mitigate some of the production, economic, and food security consequences. BXW impacts are almost completely negated when farmers have good knowledge of the disease and fully adopt the appropriate management practices. This result highlights the need for policy frameworks which rely on sustained and coordinated efforts by public and private stakeholders, within and across SSA countries and at different geographical scales. It also aims to raise awareness and promote the adoption of such practices, while also considering local peculiarities and socioeconomic conditions

Plaskett's Star: Analysis of the CoRoT photometric data

The SRa02 of the CoRoT space mission for Asteroseismology was partly devoted to stars belonging to the Mon OB2 association. An intense monitoring was performed on Plaskett's Star (HD47129) and the unprecedented quality of the light curve allows us to shed new light on this very massive, non-eclipsing binary system. We particularly aimed at detecting periodic variability which might be associated with pulsations or interactions between both components. We also searched for variations related to the orbital cycle which could help to constrain the inclination and the morphology of the binary system. A Fourier-based prewhitening and a multiperiodic fitting procedure were applied to analyse the time series and extract the frequencies of variations. We describe the noise properties to tentatively define an appropriate significance criterion, to only point out the peaks at a certain significance level. We also detect the variations related to the orbital motion and study them by using the NIGHTFALL program. The periodogram exhibits a majority of peaks at low frequencies. Among these peaks, we highlight a list of about 43 values, including notably two different sets of harmonic frequencies whose fundamental peaks are located at about 0.07 and 0.82d-1. The former represents the orbital frequency of the binary system whilst the latter could probably be associated with non-radial pulsations. The study of the 0.07d-1 variations reveals the presence of a hot spot most probably situated on the primary star and facing the secondary. The investigation of this unique dataset constitutes a further step in the understanding of Plaskett's Star. These results provide a first basis for future seismic modelling. The existence of a hot region between both components renders the determination of the inclination ambiguous.Comment: Accepted in A&A, 13 pages, 7 figures, 2 table

Study of the luminous blue variable star candidate G26.47+0.02 and its environment

The luminous blue variable (LBV) stars are peculiar very massive stars. The study of these stellar objects and their surroundings is important for understanding the evolution of massive stars and its effects on the interstellar medium. We study the LBV star candidate G26.47+0.02. Using several large-scale surveys in different frequencies we performed a multiwavelength study of G26.47+0.02 and its surroundings. We found a molecular shell (seen in the 13CO J=1-0 line) that partially surrounds the mid-infrared nebula of G26.47+0.02, which suggests an interaction between the strong stellar winds and the molecular gas. From the HI absorption and the molecular gas study we conclude that G26.47+0.02 is located at a distance of ~4.8 kpc. The radio continuum analysis shows a both thermal and non-thermal emission toward this LBV candidate, pointing to wind-wind collision shocks from a binary system. This hypothesis is supported by a search of near-IR sources and the Chandra X-ray analysis. Additional multiwavelength and long-term observations are needed to detect some possible variable behavior, and if that is found, to confirm the binary nature of the system.Comment: accepted in A&A 01/05/201

The Gaia-ESO survey : Processing FLAMES-UVES spectra

Date of Acceptance: 19/03/2014The Gaia-ESO Survey is a large public spectroscopic survey that aims to derive radial velocities and fundamental parameters of about 105 Milky Way stars in the field and in clusters. Observations are carried out with the multi-object optical spectrograph FLAMES, using simultaneously the medium-resolution (R ~ 20 000) GIRAFFE spectrograph and the high-resolution (R ~ 47 000) UVES spectrograph. In this paper we describe the methods and the software used for the data reduction, the derivation of the radial velocities, and the quality control of the FLAMES-UVES spectra. Data reduction has been performed using a workflow specifically developed for this project. This workflow runs the ESO public pipeline optimizing the data reduction for the Gaia-ESO Survey, automatically performs sky subtraction, barycentric correction and normalisation, and calculates radial velocities and a first guess of the rotational velocities. The quality control is performed using the output parameters from the ESO pipeline, by a visual inspection of the spectra and by the analysis of the signal-to-noise ratio of the spectra. Using the observations of the first 18 months, specifically targets observed multiple times at different epochs, stars observed with both GIRAFFE and UVES, and observations of radial velocity standards, we estimated the precision and the accuracy of the radial velocities. The statistical error on the radial velocities is σ ~ 0.4 km s-1 and is mainly due to uncertainties in the zero point of the wavelength calibration. However, we found a systematic bias with respect to the GIRAFFE spectra (~0.9 km s-1) and to the radial velocities of the standard stars (~0.5 km s-1) retrieved from the literature. This bias will be corrected in the future data releases, when a common zero point for all the set-ups and instruments used for the survey is be established.Peer reviewe

Risks posed by intercrops and weeds as alternative hosts to Xanthomonas campestris pv. musacearum in banana fields

Alternative host plants are important in the survival and perpetuation of several crop pathogens and have been suspected to play a role in the survival of Xanthomonas campestris pv. musacearum (Xcm) and perpetuation of Xanthomonas wilt (XW) disease of banana and enset. This study determined the potential risk posed by two weeds (Canna spp. and wild sorghum) and common banana intercrops (maize, millet, sorghum, taro, and sugarcane) as alternative hosts to Xcm. The study employed screenhouse experiments, laboratory procedures and diagnosis of banana fields in XW-affected landscapes. Typical XW symptoms were only observed in artificially inoculated Canna sp., with an incidence of 96%. Leaf lesions characteristic of xanthomonads occurred on millet (50%) and sorghum (35%), though the plants recovered. No symptoms occurred in maize, sugarcane, taro or wild sorghum. However, Xcm was recovered from all these plant species, with higher recoveries in Canna sp. (47%), millet (27%), sugarcane (27%), and wild sorghum (25%). Only isolates recovered from Canna sp., millet, sorghum and wild sorghum caused disease in banana plantlets. The presence and incidence of XW on-farm was positively associated with the presence of susceptible ABB Musa genotypes and negatively with number of banana cultivars on farm and household access to training on XW management. Only 0.02% of field sampled Canna spp. plants had Xcm. Risk posed by Canna spp. on-farm could be limited to tool transmission as it has persistent floral bracts that prevent insect-mediated infections. Given the high susceptibility, perennial nature and propagation through rhizomes of Canna sp., it could pose a moderate-high risk, thus warranting some attention in the management of XW disease. Sugarcane could offer a low-moderate risk due to its perennial nature and propagation through rhizomes while risk from maize, millet, and sorghum was deemed zero-low due to their annual nature, wind-mediated mode of pollination and propagation through seed. Understanding the interactions of a crop pathogen with other plants is thus important when diversifying agroecosystems. The study findings also suggest other factors such as cultivar composition and management of the disease at farm and landscape level to be important in the perpetuation of XW disease

Aortoiliac hemodynamic and morphologic adaptation to chronic spinal cord injury

BackgroundReduced lower limb blood flow and resistive hemodynamic conditions potentially promote aortic inflammation and aneurysmal degeneration. We used abdominal ultrasonography, magnetic resonance imaging, and computational flow modeling to determine the relationship between reduced infrarenal aortic blood flow in chronic spinal cord injury (SCI) subjects and risk for abdominal aortic aneurysm (AAA) disease.MethodsAortic diameter in consecutive SCI subjects (n = 123) was determined via transabdominal ultrasonography. Aortic anatomic and physiologic data were acquired via magnetic resonance angiography (MRA; n = 5) and cine phase-contrast magnetic resonance flow imaging (n = 4) from SCI subjects whose aortic diameter was less than 3.0 cm by ultrasonography. Computational flow models were constructed from magnetic resonance data sets. Results were compared with those obtained from ambulatory control subjects (ultrasonography, n = 129; MRA/phase-contrast magnetic resonance flow imaging, n = 6) who were recruited at random from a larger pool of risk factor–matched individuals without known AAA disease.ResultsAge, sex distribution, and smoking histories were comparable between the SCI and control groups. In the SCI group, time since injury averaged 26 ± 13 years (mean ± SD). Aortic diameter was larger (P < .01), and the prevalence of large (≥2.5 cm; P < .01) or aneurysmal (≥3.0 cm; P < .05) aortas was greater in SCI subjects. Paradoxically, common iliac artery diameters were reduced in SCI subjects (<1.0 cm; 48% SCI vs 26% control; P < .0001). Focal preaneurysmal enlargement was noted in four of five SCI subjects by MRA. Flow modeling revealed normal flow volume, biphasic and reduced oscillatory flow, slower pressure decay, and reduced wall shear stress in the SCI infrarenal aorta.ConclusionsCharacteristic aortoiliac hemodynamic and morphologic adaptations occur in response to chronic SCI. Slower aortic pressure decay and reduced wall shear stress after SCI may contribute to mural degeneration, enlargement, and an increased prevalence of AAA disease

Variability in the CoRoT photometry of three hot O-type stars. HD 46223, HD 46150 and HD 46966

The detection of pulsational frequencies in stellar photometry is required as input for asteroseismological modelling. The second short run (SRa02) of the CoRoT mission has provided photometric data of unprecedented quality and time-coverage for a number of O-type stars. We analyse the CoRoT data corresponding to three hot O-type stars, describing the properties of their light curves and we search for pulsational frequencies, which we then compare to theoretical model predictions. We determine the amplitude spectrum of the data, using the Lomb-Scargle and a multifrequency HMM-like technique. Frequencies are extracted by prewhitening, and their significance is evaluated under the assumption that the light curve is dominated by red noise. We search for harmonics, linear combinations and regular spacings among these frequencies. We use simulations with the same time sampling as the data as a powerful tool to judge the significance of our results. From the theoretical point of view, we use the MAD non-adiabatic pulsation code to determine the expected frequencies of excited modes. A substantial number of frequencies is listed, but none can be convincingly identified as being connected to pulsations. The amplitude spectrum is dominated by red noise. Theoretical modelling shows that all three O-type stars can have excited modes but the relation between the theoretical frequencies and the observed spectrum is not obvious. The dominant red noise component in the hot O-type stars studied here clearly points to a different origin than the pulsations seen in cooler O stars. The physical cause of this red noise is unclear, but we speculate on the possibility of sub-surface convection, granulation, or stellar wind inhomogeneities being responsible.Comment: 13 pages, 8 figures, A&A accepted. Tables 2, 3 and 4 available on ftp://omaftp.oma.be/dist/astro/Blomme.R/CoRoT