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See detailCharacterization of the K2-19 Multiple-Transiting Planetary System via High-Dispersion Spectroscopy, AO Imaging, and Transit Timing Variations
Narita, Norio; Hirano, Teruyuki; Fukui, Akihiko et al

E-print/Working paper (2015)

K2-19 (EPIC201505350) is an interesting planetary system in which two transiting planets with radii ~ 7 $R_{Earth}$ (inner planet b) and ~ 4 $R_{Earth}$ (outer planet c) have orbits that are nearly in a 3 ... [more ▼]

K2-19 (EPIC201505350) is an interesting planetary system in which two transiting planets with radii ~ 7 $R_{Earth}$ (inner planet b) and ~ 4 $R_{Earth}$ (outer planet c) have orbits that are nearly in a 3:2 mean-motion resonance. Here, we present results of ground-based follow-up observations for the K2-19 planetary system. We have performed high-dispersion spectroscopy and high-contrast adaptive-optics imaging of the host star with the HDS and HiCIAO on the Subaru 8.2m telescope. We find that the host star is relatively old (>8 Gyr) late G-type star ($T_{eff}$ ~ 5350 K, $M_s$ ~ 0.9 $M_{Sun}$, and $R_{s}$ ~ 0.9 $R_{Sun}$). We do not find any contaminating faint objects near the host star which could be responsible for (or dilute) the transit signals. We have also conducted transit follow-up photometry for the inner planet with KeplerCam on the FLWO 1.2m telescope, TRAPPISTCAM on the TRAPPIST 0.6m telescope, and MuSCAT on the OAO 1.88m telescope. We confirm the presence of transit-timing variations, as previously reported by Armstrong and coworkers. We model the observed transit-timing variations of the inner planet using the synodic chopping formulae given by Deck & Agol (2015). We find two statistically indistinguishable solutions for which the period ratios ($P_{c}/P_{b}$) are located slightly above and below the exact 3:2 commensurability. Despite the degeneracy, we derive the orbital period of the inner planet $P_b$ ~ 7.921 days and the mass of the outer planet $M_c$ ~ 20 $M_{Earth}$. Additional transit photometry (especially for the outer planet) as well as precise radial-velocity measurements would be helpful to break the degeneracy and to determine the mass of the inner planet. [less ▲]

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See detailThe HARPS search for southern extra-solar planets. XXXVIII. Bayesian re-analysis of three systems. New super-Earths, unconfirmed signals, and magnetic cycles
Díaz, R. F.; Ségransan, D.; Udry, S. et al

E-print/Working paper (2015)

We present the analysis of the entire HARPS observations of three stars that host planetary systems: HD1461, HD40307, and HD204313. The data set spans eight years and contains more than 200 nightly ... [more ▼]

We present the analysis of the entire HARPS observations of three stars that host planetary systems: HD1461, HD40307, and HD204313. The data set spans eight years and contains more than 200 nightly averaged velocity measurements for each star. This means that it is sensitive to both long-period and low-mass planets and also to the effects induced by stellar activity cycles. We modelled the data using Keplerian functions that correspond to planetary candidates and included the short- and long-term effects of magnetic activity. A Bayesian approach was taken both for the data modelling, which allowed us to include information from activity proxies such as $\log{(R'_{\rm HK})}$ in the velocity modelling, and for the model selection, which permitted determining the number of significant signals in the system. The Bayesian model comparison overcomes the limitations inherent to the traditional periodogram analysis. We report an additional super-Earth planet in the HD1461 system. Four out of the six planets previously reported for HD40307 are confirmed and characterised. We discuss the remaining two proposed signals. In particular, we show that when the systematic uncertainty associated with the techniques for estimating model probabilities are taken into account, the current data are not conclusive concerning the existence of the habitable-zone candidate HD40307 g. We also fully characterise the Neptune-mass planet that orbits HD204313 in 34.9 days. [less ▲]

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See detailNew and updated convex shape models of asteroids based on optical data from a large collaboration network
Hanuš, J.; Ďurech, J.; Oszkiewicz, D. A. et al

E-print/Working paper (2015)

Asteroid modeling efforts in the last decade resulted in a comprehensive dataset of almost 400 convex shape models and their rotation states. This amount already provided a deep insight into physical ... [more ▼]

Asteroid modeling efforts in the last decade resulted in a comprehensive dataset of almost 400 convex shape models and their rotation states. This amount already provided a deep insight into physical properties of main-belt asteroids or large collisional families. We aim to increase the number of asteroid shape models and rotation states. Such results are an important input for various further studies such as analysis of asteroid physical properties in different populations, including smaller collisional families, thermophysical modeling, and scaling shape models by disk-resolved images, or stellar occultation data. This provides, in combination with known masses, bulk density estimates, but constrains also theoretical collisional and evolutional models of the Solar System. We use all available disk-integrated optical data (i.e., classical dense-in-time photometry obtained from public databases and through a large collaboration network as well as sparse-in-time individual measurements from a few sky surveys) as an input for the convex inversion method, and derive 3D shape models of asteroids, together with their rotation periods and orientations of rotation axes. The key ingredient is the support of more that one hundred observers who submit their optical data to publicly available databases. We present updated shape models for 36 asteroids, for which mass estimates are currently available in the literature or their masses will be most likely determined from their gravitational influence on smaller bodies, which orbital deflection will be observed by the ESA Gaia astrometric mission. This was achieved by using additional optical data from recent apparitions for the shape optimization. Moreover, we also present new shape model determinations for 250 asteroids, including 13 Hungarias and 3 near-Earth asteroids. [less ▲]

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See detailTests of the Planetary Hypothesis for PTFO 8-8695b
Yu, Liang; Winn, Joshua N.; Gillon, Michaël ULg et al

in Astrophysical Journal (2015), 812

The T Tauri star PTFO 8-8695 exhibits periodic fading events that have been interpreted as the transits of a giant planet on a precessing orbit. Here we present three tests of the planet hypothesis. First ... [more ▼]

The T Tauri star PTFO 8-8695 exhibits periodic fading events that have been interpreted as the transits of a giant planet on a precessing orbit. Here we present three tests of the planet hypothesis. First, we sought evidence for the secular changes in light-curve morphology that are predicted to be a consequence of orbital precession. We observed 28 fading events spread over several years and did not see the expected changes. Instead, we found that the fading events are not strictly periodic. Second, we attempted to detect the planet's radiation, based on infrared observations spanning the predicted times of occultations. We ruled out a signal of the expected amplitude. Third, we attempted to detect the Rossiter-McLaughlin effect by performing high-resolution spectroscopy throughout a fading event. No effect was seen at the expected level, ruling out most (but not all) possible orientations for the hypothetical planetary orbit. Our spectroscopy also revealed strong, time-variable, high-velocity Hα and Ca H & K emission features. All these observations cast doubt on the planetary hypothesis, and suggest instead that the fading events represent starspots, eclipses by circumstellar dust, or occultations of an accretion hotspot. [less ▲]

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See detailRepenser la tarifaction de l'énergie
Gautier, Axel ULg

in Reflets et Perspectives de la Vie Economique (2015), LIV(1-2), 175-184

The distribution tariff is for historical reasons connected to the consumption level. Maintaining a tariff per KWh is in our view problematic for two reasons. First, it induces inefficient consumption or ... [more ▼]

The distribution tariff is for historical reasons connected to the consumption level. Maintaining a tariff per KWh is in our view problematic for two reasons. First, it induces inefficient consumption or production choices by consumers. Second, because of scale economies, a decrease in energy consumption leads to both a cost and a revenue decline with the latter being stronger than the former, thereby necessitating an increase in the tariff to compensate for the revenue losses and reinforcing the first effect. The distribution tariff should therefore be re-designed and de-connected, at least partially, from the consumption level. [less ▲]

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See detailPALEO-DELTA: Palaeoenvironment and geoarchaeology of the Medjerda delta (Tunisia)
Pleuger, Elisa ULg; Abichou, Hakim; Gadhoum, Ahmed et al

Poster (2015, October)

Phoenician Utica remains today largely unknown, as is its role in the Phoenician expansion in the western Mediterranean. Aristotle and Pliny the Elder mention Utica as a maritime and port city and ... [more ▼]

Phoenician Utica remains today largely unknown, as is its role in the Phoenician expansion in the western Mediterranean. Aristotle and Pliny the Elder mention Utica as a maritime and port city and estimate its origin around the 11th c. BC. However, in the present state of research, no archaeological evidence is earlier than the 9th c. BC, and the location of the Phoenician and Roman port infrastructures remains unknown. Today, the ancient city is located on a promontory in the heart of the Medjerda delta, 10 km inland. This project proposes an interdisciplinary effort to understand the Medjerda delta landscape changes during the Holocene. It starts from an archaeological problem and proposes the contribution of geoarchaeology to the understanding of the relationship between ancient societies and their environment. The fluvial palaeoenvironments and sedimentary processes are studied through the mechanical extraction of cores (15-20 m deep) to reach the early Holocene. Selected sediment samples are then studied in laboratory, using different and complementary approaches. The location of port infrastructures will bring initial answers to the question of the foundation of the city. The study of river palaeoenvironments of the Medjerda delta during the Holocene aim at a better understanding of the nature of the settlement, as well as the function of the city of Utica over time. This study will also assess the impact of the ancient city on the environment and understand how the city adapted to the mobility of this Mediterranean delta. Furthermore, the analysis of sedimentary processes causing the filling of the harbour basin will lead to speculation about the causes of the abandonment of the structures and more generally the decline of the city in favor of Carthage. It will also examine whether natural or anthropogenic factors have influenced this deltaic progradation over the centuries. [less ▲]

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See detailCROSSROADS Octobre 2015
Sacré, Robert ULg

Diverse speeche and writing (2015)

CROSSROADS, le magazine du blues et des musiques américaines ; streaming www.equinoxefm.be ; podcasts www.mixcloud.com/robertsacre9 ; infos www.facebook.com/robert.sacre.9

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See detailDescribing many-body bosonic waveguide scattering with the truncated Wigner method
Dujardin, Julien ULg; Engl, Thomas; Urbina, Juan Diego et al

in Annalen der Physik (2015), 527

We consider quasi-stationary scattering of interacting bosonic matter waves in one-dimensional waveguides, as they arise in guided atom lasers. We show how the truncated Wigner (tW) method, which ... [more ▼]

We consider quasi-stationary scattering of interacting bosonic matter waves in one-dimensional waveguides, as they arise in guided atom lasers. We show how the truncated Wigner (tW) method, which corresponds to the semiclassical description of the bosonic many-body system on the level of the diagonal approximation, can be utilized in order to describe such many-body bosonic scattering processes. Special emphasis is put on the discretization of space at the exact quantum level, in order to properly implement the semiclassical approximation and the tW method, as well as on the discussion of the results to be obtained in the continuous limit. [less ▲]

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See detailA stop-gain in the laminin, alpha 3 gene causes recessive junctional epidermolysis bullosa in Belgian Blue cattle
Sartelet, Arnaud ULg; Harland, Chad ULg; Tamma, Nico ULg et al

in Animal Genetics (2015), 46(5), 566-570

Four newborn purebred Belgian Blue calves presenting a severe form of epidermolysis bullosa were recently referred to our heredo-surveillance platform. SNP array genotyping followed by autozygosity ... [more ▼]

Four newborn purebred Belgian Blue calves presenting a severe form of epidermolysis bullosa were recently referred to our heredo-surveillance platform. SNP array genotyping followed by autozygosity mapping located the causative gene in a 8.3-Mb interval on bovine chromosome 24. Combining information from (i) whole-genome sequencing of an affected calf, (ii) transcriptomic data from a panel of tissues and (iii) a list of functionally ranked positional candidates pinpointed a private G to A nucleotide substitution in the LAMA3 gene that creates a premature stop codon (p.Arg2609*) in exon 60, truncating 22% of the corresponding protein. The LAMA3 gene encodes the alpha 3 subunit of the heterotrimeric laminin-332, a key constituent of the lamina lucida that is part of the skin basement membrane connecting epidermis and dermis layers. Homozygous loss-of-function mutations in this gene are known to cause severe junctional epidermolysis bullosa in human, mice, horse, sheep and dog. Overall, our data strongly support the causality of the identified gene and mutation. [less ▲]

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See detailLatex, un peu, beaucoup (9. Figures & tables)
Dupont, Pascal ULg

in Losanges (2015), 30

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See detailLes Mots des Maths : Trapèze
Dupont, Pascal ULg

in Losanges (2015), 30

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See detailValidation of the DermaGenius Nail plus multiplex assay, a new commercial PCR assay developed for the detection and identification of dermatophyte and Candida in nails
Hayette, Marie-Pierre ULg; GRAIDE, Hélène ULg; ADJETEY BAHUN, Akolé ULg et al

in Mycoses (2015, October), 58(suppl 4), 223

Objectives Superficial dermatophytosis is the most common fungal infection in humans. Diagnosis of dermatophytosis is currently based on microscopy or histology associated with culture on specific agar ... [more ▼]

Objectives Superficial dermatophytosis is the most common fungal infection in humans. Diagnosis of dermatophytosis is currently based on microscopy or histology associated with culture on specific agar media. However, direct microscopy lacks specificity and culturing has a long turn-around-time of 2-4 weeks. These limitations can be prevented by the use of molecular diagnostics. The DermaGenius (DG) multiplex kit (PathoNostics, The Netherlands) is a new commercial realtime-PCR kit, which can differentiate various dermatophytes species including the nail pathogens T. rubrum, T. mentagrophytes, T. interdigitale and 2 Candida species (C. albicans and C. parapsilosis). This study aimed at the validation of the kit on nails clippings. Results were compared with histology and culture data. Methods A set of 76 nail clippings was collected from 76 patients attending the dermatology consultation at the University Hospital of Liege on suspicion of onychomycosis. All nails were divided in three pieces for histology, culture and the PCR multiplex assay. Histologic preparations were stained with PAS staining. Cultures were performed on 2 different Sabouraud agar medium slants (bioMérieux). The DNA extraction protocol used a proteinase K pre-treatment followed by an automated DNA-extraction (EasyMag, bioMérieux). An Internal Control (IC) was included to monitor for PCR inhibition or manual errors. The realtime-PCR amplification was performed with the DG kit on a Rotor-Gene Q instrument (Qiagen) by using quantitative amplification and melting curve analysis. Results In total, 35 of 76 cases (46%) were classified as confirmed onychomycosis based on positive microscopy (M+) with or without positive culture (C+) or just by positive culture of a confirmed pathogen. Based on negative microscopy (M-) and negative culture of a confirmed pathogen, 41 cases (54%) were reported as non-fungal onychodystrophy. Agreement between DermaGenius (DG) and culture was found in 52% of the cases while 86% agreement was reported when comparing positive DG with confirmed onychomycosis. Three positive cultures (microscopy negative) were not detected by DG (2 T. rubrum, 1 C. albicans). However, DG could detect 7 additional infections (9%). Eleven discrepancies DG+/C+ were determined which could be positively confirmed in favour of DG result by ITS sequence analysis. Most discrepancies could be explained by fungal/yeast species overgrowing the agar slant, including species of Candida, Fusarium, Trichosporon, which were not considered as the source of infection. Conclusion The DermaGenius Nail plus multiplex was able to detect the most prevalent pathogenic dermatophytes species in clinical nail specimens and proved to be more sensitive and specific than culture and direct microscopy. The DNA extraction procedure has been shown to work efficiently in diagnostics which enables the physician in charge of the patient to start a dedicated treatment rapidly. [less ▲]

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See detailUsing kernels and ecological niche modeling to delineate conservation areas in an endangered patch-breeding phenotype
Denoël, Mathieu ULg; Ficetola, Francesco

in Ecological Applications (2015), 25(7), 1922-1931

Efficient delineation of conservation areas is a great challenge in maintaining biodiversity. Kernel density estimators (KDEs) are a powerful tool in this perspective, but they have not been applied at ... [more ▼]

Efficient delineation of conservation areas is a great challenge in maintaining biodiversity. Kernel density estimators (KDEs) are a powerful tool in this perspective, but they have not been applied at the population level on patch-distributed organisms. This would be particularly worthy for species that need broad habitats beyond those where they can be sampled; such as terrestrial lands for pond-breeding amphibians. The aim of this study was to compare different approaches for the identification of suitable areas for conservation: KDE, ecological niche modelling, and a combination of KDE and niche models. Paedomorphosis was chosen as a model system because this is an important form of intraspecific variation that is present in numerous taxa, but geographically localized within species and globally endangered. 277 ponds were sampled in one of the hotspots of paedomorphosis to determine the abundance and distribution of paedomorphs (i.e. individuals retaining gills at the adult stage) of the palmate newt (Lissotriton helveticus), with emphasis on the connections between the most valuable populations. KDEs gave insights into the surface areas required to balance the maintenance of certain number of connected ponds and the respective number of disjoint areas in which the whole population is divided. The inclusion of barriers in the models helped in accurately designing the limits of the areas to protect. Alone, habitat models were not able to successfully delineate the area to protect, but the integration between terrestrial suitable areas or barriers and KDE allowed an objective identification of areas required for conservation. Overall, the best performance was observed by the KDE integrating ecological barriers, and by the combination between KDE and niche modelling. In a broader perspective, KDEs are thus a pertinent tool in providing quantitative spatial measurements to delineate conservation areas based on patch-abundance data with a specific focus to connectivity. [less ▲]

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See detailMarchés énergétiques en transition : le cas de la Belgique
Agrell, Per; Gautier, Axel ULg

in Reflets et Perspectives de la Vie Economique (2015), LIV(1-2), 5-6

Foreword by Per Agrell and Axel Gautier

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See detailPour ou contre les cellules souches ?
Goetghebuer, Gilles; Kaux, Jean-François ULg

Article for general public (2015)

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See detailEnzymatic functionalization of a nanobody using protein insertion technology
Crasson, Oscar ULg; Rhazi, Noureddine; Jacquin, Olivier et al

in Protein Engineering, Design & Selection (2015), 28(10), 451-460

Antibody-based products constitute one of the most attractive biological molecules for diagnostic, medical imagery and therapeutic purposes with very few side effects. Their development has be- come a ... [more ▼]

Antibody-based products constitute one of the most attractive biological molecules for diagnostic, medical imagery and therapeutic purposes with very few side effects. Their development has be- come a major priority of biotech and pharmaceutical industries. Recently, a growing number of modified antibody-based products have emerged including fragments, multi-specific and conjugate antibodies. In this study, using protein engineering, we have functionalized the anti-hen egg-white lysozyme (HEWL) camelid VHH antibody fragment (cAb-Lys3), by insertion into a solvent-exposed loop of the Bacillus licheniformis β-lactamase BlaP. We showed that the generated hybrid protein conserved its enzymatic activity while the displayed nanobody retains its ability to inhibit HEWL with a nanomolar affinity range. Then, we successfully implemented the functionalized cAb-Lys3 in enzyme-linked immunosorbent assay, potentiometric biosensor and drug screening assays. The hybrid protein was also expressed on the surface of phage particles and, in this context, was able to interact specifically with HEWL while the β-lactamase activity was used to monitor phage interactions. Finally, using thrombin-cleavage sites surrounding the permissive insertion site in the β-lactamase, we reported an expression system in which the nanobody can be easily separated from its carrier protein. Altogether, our study shows that insertion into the BlaP β-lactamase consti- tutes a suitable technology to functionalize nanobodies and allowsthe creation of versatile tools that can be used in innovative biotechnological assays. [less ▲]

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See detailOnychomycosis: is it possible to increase the cure rate?
Hayette, Marie-Pierre ULg

in Mycoses (2015, October), 58(suppl 4), 35

Onychomycosis represent about 50% of nails disorders in the world with a very variable prevalence depending of the countries considered. Dermatophytes, non-dermatophyte molds and Candida sp. are the main ... [more ▼]

Onychomycosis represent about 50% of nails disorders in the world with a very variable prevalence depending of the countries considered. Dermatophytes, non-dermatophyte molds and Candida sp. are the main causing agents. A rapid and accurate diagnosis is essential in order to give an adequate treatment to the patient. Generally, a combination of microscopy and culture is used for laboratory diagnosis. However, microscopy does not always allow the distinction between yeasts or filamentous fungi, culture takes generally about a week before identification and the result is compromised if there is contamination by not relevant fungi. Therefore commercially available PCR-based methods have been developed in order to provide a rapid and accurate identification of dermatophytes and yeasts in nails samples. Combination of microscopy and PCR may provide a rapid and specific diagnosis in 2 working days. However this methodology is still not widely used by laboratories because of the high cost. Furthermore, this technology can detect DNA from dead fungi and therefore is not suitable for assessment of treatment efficacy. Onychomycosis therapy depends on different factors such as the causative agent, the number of nails and degree of nail involvement, the type of onychomycosis, potential drug interactions or drug intolerance and a failure to previous treatments. Oral and topical antifungals are mostly used separately or in combination. Oral therapy includes azoles (itraconazole, fluconazole) and/or allylamine (terbinafin), this latter being the most frequently prescribed antifungal for treatment of onychomycosis in North America and Europe. Topical amorolfine and ciclopirox formulations can be used alone in mild cases or in case of intolerance to oral antifungals. However, one of the biggest problems of therapy for onychomycosis is the high frequency of relapse which concerns about 20 to 40% of the patients treated by oral antifungals. Different strategies have been developed to overcome this problem amongst which are: optimization of the dosing regimens (continuous vs pulse therapy) or therapy duration, combination therapy (nail debridement + antifungals, oral + topical drugs, 2 oral drugs), improving drug delivery (use of physical or chemical enhancers, and modification of the pharmacological formulation for increasing drug uptake). Some strategies such as combination therapy (oral + topical) have demonstrated enhanced efficacy and should be recommended in case of poor efficacy of the initial treatment or in case of extended infection. Prophylactic topical therapy implemented after completion of oral treatment has been shown to delay relapse. Preventive measures such as treatment of concurrent tinea pedis and/or infected family members and regular cleaning of bathroom and shower floors can help to reduce the risk of reinfection particularly when a dermatophyte is the causative agent. In conclusion, treatment for onychomycosis is associated with frequent relapse. Consequently, follow-up is mandatory and combination therapy can be necessary in case of relapse or resistance to treatment. Patients should also be aware of the preventive hygiene measures to apply in order to decrease the risk of reinfection. New strategies improving treatment efficacy are promising but their efficacy have still to be demonstrated in comparative clinical trials before their implementation in therapy. [less ▲]

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See detailEpidemiological aspects and genotypic characterization of T.violaceum strains collected during a Belgian National survey on anthropophilic tinea
SACHELI, Rosalie ULg; Dekkers, Charlotte; GRAIDE, Hélène ULg et al

in Mycoses (2015, October), 58(Supplement 4), 189

Objectives The last two years, clinical cases of tinea capitis caused by Trichophyton violaceum (T. violaceum), have been identified in Belgium. To better understand the emergence of this species in the ... [more ▼]

Objectives The last two years, clinical cases of tinea capitis caused by Trichophyton violaceum (T. violaceum), have been identified in Belgium. To better understand the emergence of this species in the population, the Belgian National Reference Center (NRC Liège) launched a one-year national survey in 2013. Epidemiological aspects and genotypic characterization of the strains were included. Methods The study was conducted from March 2013 up to February 2014. All Belgian laboratories were asked to send M. audouinii and T. violaceum strains isolated from hair to the NRC with a form to fill in including epidemiological data. The fungal strains were identified by microscopy or ITS sequencing in case of doubtful identification. The genotypic analysis was performed by the DiversiLab® system (bioMérieux) for DNA fingerprinting and analysis. Epidemiological data were analyzed with the help of a biostatistician. Results Amongst the collected isolates, 23 strains were confirmed as T.violaceum (results concerning the 116 M. audouinii strains have already been reported). Analysis of the epidemiological characteristics of the infected population shows that the main age category concerns 0-4 year-old children (n=9, 39,1%) with a sex-ratio M/F of 1.875. Data concerning the geographic origin of the family were present in 82,6% of the cases and reveal that patients were mainly of Ethiopian origin (n=8, 57,9% of known cases). One patient was also from Burundi showing that T. violaceum strains probably circulate mainly in East Africa. The genotypic analysis led to the distinction of 2 variants of T. violaceum. The major group was composed of 17 strains which were mainly collected in the North of Belgium and included also the reference strain (18/23, 83,3%). The other group (6 strains) was close to the major group but the analysis of the spectral superposition showed some differences between these two groups, defining two distinct variants of T. violaceum in the Belgian population. This second variant was mainly recovered from South Belgium (5/6, 83,3%). No correlation could be made between the genotypic group and a particular ethnical origin as Ethiopian subjects were found in both groups. Conclusion The DiversiLab® system proved to be an efficient method to investigate the molecular epidemiology of dermatophytes infections as reported previously for M. audouinii. These results show that two distinct isolates co-exist in Belgium providing evidence of genetic heterogeneity and a possible spread of one genotypic variant in a restricted geographic area or the co-existence of two variants circulating in different African communities. However, no clear correlation could be established between the appartenance to a group and epidemiological factors, such as age or ethnical origin. [less ▲]

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See detailHigh reactive oxygen species in fibrotic and non-fibrotic skin of Patients with diffuse cutaneous systemic sclerosis
BOURJI, Khalil; MEYER, Alain; CHATELUS, Emmanuel et al

in Free Radical Biology & Medicine (2015), 87

Systemic Sclerosis (SSc) is a chronic multisystemic connective tissue disease characterized by progressive fibrosis affecting skin and internal organs. Despite serious efforts to unveil the pathogenic ... [more ▼]

Systemic Sclerosis (SSc) is a chronic multisystemic connective tissue disease characterized by progressive fibrosis affecting skin and internal organs. Despite serious efforts to unveil the pathogenic mechanisms of SSc, they are still unclear. High levels of Reactive Oxygen Species (ROS) in affected patients have been shown, and ROS are suggested to play a role in fibrosis pathogenesis. In this study we evaluate ROS levels in non-fibrotic and fibrotic skin of patients with SSc and we compare them with those obtained from healthy controls. Patients and Methods We enrolled 9 SSc patients fulfilling the EULAR/ACR classification criteria and 7 healthy controls. Patients included were 4 men and 5 women with mean age of 46 ±10 yrs. Controls were matched by sex and age. All patients were affected by diffuse cutaneous form of SSc and the ANA pattern anti-Scl70. Mean disease duration was 7.5±5 yrs. Skin involvement was evaluated by modified Rodnan Skin Score (mRSS). Skin samples (4 mm punch biopsy) were taken from fibrotic skin and non-fibrotic skin of patients and from healthy controls as well. To detect ROS, specimens were analyzed immediately after sampling by electron paramagnetic resonance spectroscopy. Blood samples have been drawn from all patients and controls to assess oxidative stress biomarkers. Results ROS levels (expressed as median and range, unit of measurement was nmol/l/min/mg of dry weight) were 24.7 (10.9– 47.0) in fibrotic skin, 18.7 (7.3–34.0) in non-fibrotic skin and 7.7 (3.5–13.6) in healthy controls skin. ROS levels in Fibrotic and Non-fibrotic skin of SSc patients were significantly higher than in Healthy Controls (p=0.002 and p=0.009, respectively). ROS levels in fibrotic skin were raised in comparison to non-fibrotic skin, when samples related to each patient were compared (p=0.01). ROS levels in fibrotic skin were correlated with forced vital capacity (r= -0.75, p=0.02) and erythrocyte sedimentation rate (r=0.70, p=0.04). All other clinical and lab parameters showed no significant correlation. When compared to controls, blood from SSc patients showed lower ascorbate (vitamin C) levels (8 [3.8-9.8] vs. 10.5 [9-19.1] mg/L, p=0.004) and higher lipid peroxides (873.5 [342-1973] vs. 422 [105-576] μmol/L, p=0.004). Conclusion Our results indicate the presence of high oxidative stress both in non-fibrotic skin and fibrotic skin of SSc patients, but with higher tendency in the latter. Raised ROS levels in non-fibrotic skin of SSc patients might be a hint of early involvement in skin fibrogenesis. However, a longitudinal prospective study is necessary for such proof. [less ▲]

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