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See detailComparative study of mature and zymogen mite cysteine protease stability and pH unfolding.
Chevigne, A.; Dumez, Marie-Eve ULg; Dumoulin, Mireille ULg et al

in Biochimica et Biophysica Acta (2010), 1800(9), 937-945

BACKGROUND: Papain-like proteases (CA1) are synthesized as inactive precursors carrying an N-terminal propeptide, which is further removed under acidic conditions to generate active enzymes. METHODS: To ... [more ▼]

BACKGROUND: Papain-like proteases (CA1) are synthesized as inactive precursors carrying an N-terminal propeptide, which is further removed under acidic conditions to generate active enzymes. METHODS: To have a better insight into the mechanism of activation of this protease family, we compared the pH unfolding of the zymogen and the mature form of the mite cysteine protease Der p 1. RESULTS: We showed that the presence of the propeptide does not significantly influence the pH-induced unfolding of the catalytic domain but does affect its fluorescence properties by modifying the exposure of the tryptophan 192 to the solvent. In addition, we demonstrated that the propeptide displays weaker pH stability than the protease domain confirming that the unfolding of the propeptide is the key event in the activation process of the zymogen. GENERAL SIGNIFICANCE: Finally, we show, using thermal denaturation and enzymatic activity measurements, that whatever the pH value, the propeptide does not stabilize the structure of the catalytic domain but very interestingly, prevents its autolysis. [less ▲]

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See detailComparative study of Murid gamma-herpesvirus 4 infection in mice and in a natural host, the bank voles.
François, Sylvie ULg; Vidick, Sarah ULg; Sarlet, Michaël ULg et al

in Journal of General Virology (The) (2010)

Gamma-herpesviruses are archetypal pathogenic persistent viruses. The known human gamma-herpesviruses (Epstein-Barr virus and Kaposi's Sarcoma-associated Herpesvirus) are host-specific and therefore lack ... [more ▼]

Gamma-herpesviruses are archetypal pathogenic persistent viruses. The known human gamma-herpesviruses (Epstein-Barr virus and Kaposi's Sarcoma-associated Herpesvirus) are host-specific and therefore lack a convenient in vivo infection model. This makes related animal gamma-herpesviruses an important source of information. We are studying Murid herpesvirus 4 (MuHV-4), a virus originally isolated from bank voles (Myodes glareolus). MuHV-4 infection of inbred laboratory mouse strains (Mus musculus) is commonly used as a general model of gamma-herpesvirus pathogenesis. However, MuHV-4 has not been isolated from house mice, and no systematic comparison has been made between experimental MuHV-4 infections of mice and bank voles. We have therefore characterized MuHV-4 (strain MHV-68) infection of bank voles, both through global luciferase imaging and through classical virological methods. As in mice, intranasal virus inoculation led to productive replication in bank vole lungs, accompanied by massive cellular infiltrates. However, the extent of lytic virus replication was ~1000 fold lower in bank voles than in mice. Peak latency titers in lymphoid tissue were also lower, although latency was still established. Finally, we tested viral transmission between animals maintained in captivity. However, as observed in mice, MuHV-4 did not transmit between voles in these conditions. In conclusion, this study revealed that despite quantitative differences, replication and latency sites of MuHV-4 are comparable in bank voles and in mice. It appears therefore so far that Mus musculus represents a suitable host for studying gamma-herpesvirus pathogenesis with MuHV-4. Establishing transmission conditions in captivity will be a vital step for further research in that field. [less ▲]

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See detailComparative study of Murid gammaherpesvirus 4 infection in mice and in its natural host, the bank voles.
François, Sylvie ULg; Vidick, Sarah ULg; Koteja, Pawel et al

Poster (2009, December 11)

Gammaherpesviruses are the archetypes of persistent viruses that have been identified in a range of animals from mice to man. They are host-range specific and establish persistent, productive infections ... [more ▼]

Gammaherpesviruses are the archetypes of persistent viruses that have been identified in a range of animals from mice to man. They are host-range specific and establish persistent, productive infections of immunocompetent hosts. Thus, infected individuals simultaneously both elicit antiviral protective immune response and secrete infectious virions. The best studied gammaherpesviruses are Human herpesvirus 4 and Human herpesvirus 8. As these viruses have no well-established in vivo infection model, related animal gammaherpesviruses are an important source of information. We are studying Murid herpesvirus 4 (MuHV-4), a virus that has originally been isolated from bank voles (Myodes glareolus). Although MuHV-4 has not been isolated from house mice (Mus musculus), infection of inbred laboratory mouse strains is commonly accepted as a good model for studying gammaherpesviruses in vivo. It has however never been possible to monitor viral reexcretion and virus transmission in this species suggesting that this model could be imperfect. In this study, we therefore characterized MuHV-4 infection in its natural host, the bank voles, through classical virological methods but also through global luciferase imaging for an anatomical complete view of the infection. Results obtained show that, after intra-nasal infection, the natural route of infection is similar in mice and voles. Following nasal productive infection, the virus spreads to the lung where the infection is accompanied by massive cellular infiltrates. By opposition to extensive viral replication observed in mice, the different analyses indicated that the viral replication was ~1000 fold lower in bank voles. This lower replication did however not affect colonization of latency sites in superficial cervical lymph nodes and spleen as measured by real-time PCR quantification of viral genomes in these organs. In conclusion, this study revealed that MuHV-4 can experimentally infect bank voles, the supposed natural host, but with a lower replicative power. As, gammaherpesvirus epidemiology indicates that transmission correlates with the latent load, our results suggest that gammaherpesviruses may have evolved to infect their hosts without extensive lytic spread. In the future, establishment of experimental transmission in a population of Myodes glareolus should help us to better understand mechanisms used by gammaherpesviruses to evade immune response. [less ▲]

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See detailComparative study of numerical explicit schemes for impact problems
Nsiampa, Nestor; Ponthot, Jean-Philippe ULg; Noels, Ludovic ULg

in International Journal of Impact Engineering (2008), 35(12), 1688-1694

Explicit numerical schemes are used to integrate in time finite element discretization methods. Unfortunately, these numerical approaches can induce high-frequency numerical oscillations into the solution ... [more ▼]

Explicit numerical schemes are used to integrate in time finite element discretization methods. Unfortunately, these numerical approaches can induce high-frequency numerical oscillations into the solution. To eliminate or to reduce these oscillations, numerical dissipation can be introduced. The paper deals with the comparison of three different explicit schemes: the central difference scheme which is a nondissipative method, the Hulbert Chung dissipative explicit scheme and the Tchamwa-Wielgosz dissipative scheme. Particular attention is paid to the study of these algorithms’ behavior in problems involving high-velocity impacts like Taylor anvil impact and bullet-target interactions. It has been shown that Tchamwa-Wielgosz scheme is efficient in filtering the high-frequency oscillations and is more dissipative than Hulbert Chung explicit scheme. Although its convergence rate is only first order, the loss of accuracy remains limited to acceptable values. [less ▲]

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See detailA comparative study of O2 measurements in experimental (Interice II) and natural (ISPOL, Western Weddell Sea, Antarctica) first-year sea ice
Tison, Jean-Louis; Mock, T.; Thomas, David et al

Poster (2006, December)

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See detailA comparative study of oral acetylsalicyclic acid and metoprolol for the prophylactic treatment of migraine. A randomized, controlled, double-blind, parallel group phase III study.
Diener, H. C.; Hartung, E.; Chrubasik, J. et al

in Cephalalgia : An International Journal of Headache (2001), 21(2), 120-8

This study was a multinational, multicentre, double-blind, active controlled phase III trial designed to investigate efficacy and safety of 300 mg acetylsalicyclic acid (ASA) (n = 135) vs. 200 mg ... [more ▼]

This study was a multinational, multicentre, double-blind, active controlled phase III trial designed to investigate efficacy and safety of 300 mg acetylsalicyclic acid (ASA) (n = 135) vs. 200 mg metoprolol (n = 135) in the prophylaxis of migraine. In total 270 (51 male and 219 female) patients, aged 18-65 years, suffering between two and six migraine attacks per month were recruited. The main objective was to show equivalence with respect to efficacy, defined as a 50% reduction in the rate of migraine attacks. A run-in phase was carried out with placebo for 4 weeks, followed by a 16-week drug phase. In both treatment groups the median frequency of migraine attacks improved during the study period, from three to two in the ASA group and from three to one in the metoprolol group; 45.2% of all metoprolol patients were responders compared with 29.6% with ASA. Medication-related adverse events were less frequent in the ASA group (37) than in the metoprolol group (73). The findings from this trial show that metoprolol is superior to ASA for migraine prophylaxis but has more side-effects. Acetylsalicylic acid is better tolerated than metoprolol. Using a strict responder criterion ASA showed a responder rate comparable with the placebo rate in the literature. [less ▲]

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See detailA Comparative Study of Path Performance Metrics Predictors
Narino Mendoza, Juan Pablo; Donnet, Benoît ULg; Dupont, Pierre

in Advanced Learning for Networking Workshop (2009, June)

Using quality-of-service (QoS) metrics for Internet traffic is expected to improve greatly the performance of many network enabled applications, such as Voice-over-IP (VoIP) and video conferencing ... [more ▼]

Using quality-of-service (QoS) metrics for Internet traffic is expected to improve greatly the performance of many network enabled applications, such as Voice-over-IP (VoIP) and video conferencing. However, it is not possible to constantly measure path performance metrics (PPMs) such as delay and throughput without interfering with the network. In this work, we focus on PPMs measurement scalability by considering machine learning techniques to estimate predictive models from past PPMs observations. Using real data collected from PlanetLab, we provide a comparison between three different predictors: AR(MA) models, Kalman filters and support vector machines (SVMs). Some predic- tors use delay and throughput jointly to take advantage of the possible relationship between PPMs, while other predictors consider PPMs individually. Our current results illustrate that the best performing model is an individual SVM specific to each time series. Overall, delay can be predicted with very good accuracy while accurate forecasting of throughput remains an open problem. [less ▲]

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See detailComparative study of period determination methods
Manfroid, Jean ULg; Heck, A.; Mersch, G.

in Statistical Methods in Astronomy (1983, November 01)

Simulations have been run to compare the performance of several period determination algorithms: essentially Fourier's, Lafler-Kinman's and Stellingwerf's methods have been considered, as well as a couple ... [more ▼]

Simulations have been run to compare the performance of several period determination algorithms: essentially Fourier's, Lafler-Kinman's and Stellingwerf's methods have been considered, as well as a couple of variants. The application to single-periodic phenomena shows that none of the methods is clearly superior to the others. Fourier's and the non-parametric methods have relatively different scopes and they are, to some extent, complementary. [less ▲]

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See detailComparative study of pirlindole, a selective RIMA, and its two enantiomers using biochemical and behavioural techniques.
Bruhwyler, J.; Liégeois, Jean-François ULg; Gerardy, J. et al

in Behavioural Pharmacology (1998), 9(8), 731-7

The interaction with monoamine oxidase A (MAO-A) and B has been shown to be sensitive to the absolute configuration of molecules. Therefore, the aim of this study was to compare the effects of the racemic ... [more ▼]

The interaction with monoamine oxidase A (MAO-A) and B has been shown to be sensitive to the absolute configuration of molecules. Therefore, the aim of this study was to compare the effects of the racemic pirlindole (a selective and reversible MAO-A inhibitor) and its two enantiomers using biochemical techniques (in vitro and ex vivo determination of rat brain MAO-A and MAO-B activity) and behavioural models (forced swimming test and reserpine-induced hypothermia and palpebral ptosis test). In vitro, the MAO-A IC50 of (+/-)-pirlindole, R-(-)-pirlindole and S-(+)-pirlindole were 0.24, 0.43 and 0.18 microM, respectively. Ex vivo, their ID50 were 24.4, 37.8 and 18.7 mg/kg i.p. The differences between the three compounds were not significant, with a ratio between the two enantiomers [R-(-)/S-(+)] of 2.2 in vitro and 2.0 ex vivo. MAO-B was only slightly inhibited. In the forced swimming test and the reserpine-induced hypothermia and ptosis model, the three compounds had an antidepressant profile. In the forced swimming test, the minimal effective dose ratio between the R-(-) and the S-(+) was again around 2.0. The behavioural observations were thus clearly in accordance with the biochemical data. [less ▲]

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See detailComparative study of psychopathological features and temporalis second exteroceptive silent period in chronic tension-type headache: is 5-HT the common denominator?
Dawans, A.; Schoenen, Jean ULg; Timsit, M. et al

in Olesen, J.; Saxena, P. R. (Eds.) 5-Hydroxytrytamine Mechanisms in Primary Headaches (Frontiers in Headache Research) (1992)

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See detailA comparative study of quantitative shape analysis techniques in sedimentology
Pirard, Eric ULg; Hoyez, Bernard

in Zentralblatt für Geologie und Paläontologie. Teil I, Allgemeine, Angewandte, Regionale und Historische Geologie (1995), 1(H11/12), 1061-1066

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See detailA comparative study of reporter gene activities in fish cells and embryos
Sekkali, B.; Hellemans, B.; Belayew, A. et al

in Molecular Marine Biology and Biotechnology (1994), 3

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See detailA comparative study of sexual product quality in F1 hybrids of the bream Abramis brama X the silver bream Blicca bjoerkna
Nzau Matondo, Billy ULg; Ovidio, Michaël ULg; Philippart, Jean-Claude ULg et al

in Fisheries Science (2012), 78

The gonadosomatic index at spawning, absolute fecundity, and egg size for the female sexual products as well as the density and consistency of semen for the male sexual products were examined in cultured ... [more ▼]

The gonadosomatic index at spawning, absolute fecundity, and egg size for the female sexual products as well as the density and consistency of semen for the male sexual products were examined in cultured Abramis brama 9 Blicca bjoerkna F1 hybrids and compared with the parental species at their first sexual maturity. Females ovulated under environmental conditions, and their eggs were weighed, counted and measured. Semen of males was macroscopically examined and spermatozoa counted using a hemocytometer. Results revealed that hybridization affected the quality of female and male gametes but with an overlap between hybrids and parents. The gonadosomatic index and fecundity were significantly lower than those of parental species. Egg sizes in hybrids showed a parental effect but to the benefit of hybrids. Semen of hybrids was more diluted which was classified into two groups: the white semen overlapping slightly with parents and the aqueous without any overlap with parents. Overlapped areas between hybrids and parents in term of quality of sexual products could translate that females and males of these hybrids have the biological capacity to produce high quality gametes and thus, a greater chance to produce F2 and backcross generations in rivers. [less ▲]

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See detailCOMPARATIVE STUDY OF SPR BIOSENSORS BASED GOLD AND SILVER COLLOIDAL NANOPARTICLES
Lismont, Marjorie ULg; Dreesen, Laurent ULg

Poster (2011, June)

Noble metal nanoparticles (NPs) can be used as a robust tool for optical bio-sensing. These NPs are known for their strong interactions with light through their surface plasmon resonance (SPR), which ... [more ▼]

Noble metal nanoparticles (NPs) can be used as a robust tool for optical bio-sensing. These NPs are known for their strong interactions with light through their surface plasmon resonance (SPR), which corresponds to the collective oscillations of the conduction electrons on the particles [1]. Among metals, silver and gold NPs are of particular interest not only because they are air-stable but also because their SPR absorption bands are in the visible and near ultra-violet spectral regions, that appear as the most appropriate for technological applications [2]. The first advantage of such optical SPR biosensors is their ability to measure complex formation in real time. Indeed, the SPR absorption spectrum band of the NPs is sensitive to the shape, size, inter-particle distance and composition of the NP as well as the dielectric properties of the surrounding medium [2]. Because of the sensitivity of SPR to the local dielectric environment, plasmonic NPs can act as transducers that convert small changes in the local refractive index and the inter-particle distance into spectral shifts and broadening in the absorption spectra bands [3]. Biotin is a water-soluble B complex vitamin necessary for the production of fatty acids and the metabolism of fats and amino acids. The avidin is a tetrameric protein which can react with biotin to form the strongly bonded biotin-avidin complex.The prototypical biotin-avidin interaction forms the basis of a simple sol-based diagnostic technique for biological analytes. We focused on this well-known couple of bio-molecules to compare optical properties of silver and gold colloidal NPs. Gradual changes with time in the absorption spectra bands of biotinylated 10 nm silver and gold NPs were studied as a function of added avidin. After avidin addition, an increased red-shift of the SPR wavelength and a broadening of the absorption band with time are observed. These changes in the optical properties of colloidal NPs are due to the biomolecular recognition process between biotin and avidin which leads to aggregation of these NPs arising from cross-linking by the tetrameric protein. Moreover, the recognition process induces a variation of the local refractive index around these NPs and thus induces a red-shift of SPR also. The maximum SPR red-shift was reached after 45 minutes and was equal to 25 nm and 15 nm for silver NPs and gold NPs respectively. We concluded that the dielectric sensitivity of gold NPs is smaller than the silver NPs one for a same geometry and for an equivalent concentration of avidin. Therefore, the silver sol is more adapted to detection of avidin than the gold sol. The detection limit, described as the lowest concentration for clear identification of wavelength shift [4] due to biomolecular recognition is determined to be 4 nM for both silver and gold NPs. In this case, the corresponding wavelength shift is about 3 nm. The specificity of the interaction between biocytin and avidin was checked by replacing avidin by BSA. When BSA was added, we observed a SPR shift which was smaller than the detection limit of 3 nm. Future works will be devoted to transpose this kind of biomolecular recognition experiments on gold nanorods in order to improve the dynamic phototherapy efficiency of cancers. [less ▲]

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See detailA Comparative Study of the Antimycotic Activity of a Miconazole Hp-Beta Cyclodextrin Solution and a Surfactant Solution
Piel, Géraldine ULg; Hayette, Marie-Pierre ULg; Evrard, Brigitte ULg et al

in Journal de Pharmacie de Belgique (1999), 54(3, May-Jun), 87-8

The antimycotic activity of a new parenteral solution containing miconazole was compared to that of a marketed solution (Daktarin IV solution). This solution has been withdrawn from the belgian market ... [more ▼]

The antimycotic activity of a new parenteral solution containing miconazole was compared to that of a marketed solution (Daktarin IV solution). This solution has been withdrawn from the belgian market probably because of the toxic effects related to the presence of polyoxyl 35 castor oil. We propose a new formulation containing 10 mg of miconazole per ml (as the marketed solution), in combination with HP-beta cyclodextrin and lactic acid. The MIC of these two solutions were determined by broth microdilution method (following the NCCLS guidelines) against 15 yeasts and 16 filamentous fungi isolates. This study showed that MIC obtained with these two solutions are not significantly different. In vitro, the cyclodextrin solution has the same antimycotic activity as the Daktarin IV solution and can be proposed as a safe and effective parenteral solution to replace the previous surfactant solution. [less ▲]

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See detailComparative study of the body surface electrocardiogram in double-muscled and conventional calves.
Amory, Hélène ULg; Rollin, Frédéric ULg; Genicot, Bruno et al

in Canadian Journal of Veterinary Research = Revue Canadienne de Recherche Vétérinaire (1993), 57(3), 139-45

The purpose of this work was to study electrocardiographic features of double-muscled beef cattle. Electrocardiograms were recorded on one to six occasions from each of a group of 18 conventional calves ... [more ▼]

The purpose of this work was to study electrocardiographic features of double-muscled beef cattle. Electrocardiograms were recorded on one to six occasions from each of a group of 18 conventional calves of the Friesian breed and 29 double-muscled calves of the Belgian White and Blue breed. Ages of the calves at the times of examination ranged from eight to 348 days. The Holmes semi-orthogonal lead system was used. The waves and interval durations and the tridimensional P, QRS, and T modal vector orientation and amplitude were calculated. The magnitude of the cardiac vectors was significantly lower and the ventricular waves and QT interval duration significantly shorter in the double-muscled than in the conventional calves. The P modal vector pointed significantly less downwards and the QRS modal vector pointed significantly more forwards and less up- and rightwards in the Belgian White and Blue, than in the Friesian group. Most of the observed differences might be a consequence of the bodily, and more specifically the thoracic, conformation of the former calves. However, the lower cardiac vector magnitude and shorter wave and interval durations might also reflect lower cardiac mass in the double-muscled subjects. [less ▲]

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See detailComparative study of the competitive models for the forward scattering data at high energies
Ezhela, V. V.; Lugovsky, S. B.; Tkachenko, N. P. et al

in Prokudin, A. V.; Petrov, V. (Eds.) ELASTIC AND DIFFRACTIVE SCATTERING (2000)

Detailed reference viewed: 14 (3 ULg)