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Peer Reviewed
See detailMechanisms of inflammation in equine airways
Lekeux, Pierre ULg; Bureau, Fabrice ULg; Art, Tatiana ULg et al

in Proceedings : 3er Congreso Iberoamericano de Veterinarios Especializados en Equinos, Montevideo (2001)

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See detailMechanisms of Interaction of Endocrine-Disrupting Chemicals with Glutamate-Evoked Secretion of Gonadotropin-Releasing Hormone
Rasier, Gregory; Parent, Anne-Simone ULg; Gerard, Arlette ULg et al

in Toxicological Sciences (2008), 102(1), 33-41

In previous studies, we detected a dichlorodiphenyltrichloroethane (DDT) derivative in the serum of children with sexual precocity after migration from developing countries. Recently, we reported that DDT ... [more ▼]

In previous studies, we detected a dichlorodiphenyltrichloroethane (DDT) derivative in the serum of children with sexual precocity after migration from developing countries. Recently, we reported that DDT stimulated pulsatile gonadotropin-releasing hormone (GnRH) secretion and sexual maturation in the female rat. The aim of this study was to delineate the mechanisms of interaction of endocrine-disrupting chemicals including DDT with GnRH secretion evoked by glutamate in vitro. Using hypothalamic explants obtained from 15-day-old female rats, estradiol (E2) and DDT caused a concentration-related increase in glutamate-evoked GnRH release while p,p'-dichlorodiphenyldichloroethene and methoxychlor had no effect. The effective DDT concentrations in vitro were consistent with the serum concentrations measured in vivo 5 days after exposure of immature rats to 10 mg/kg/day of o,p'-DDT. Bisphenol A induced some stimulatory effect, whereas no change was observed with 4-nonylphenol. The o,p'-DDT effects in vitro were prevented partially by a selective antagonist of the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) subtype of glutamate receptors. A complete prevention of o,p'-DDT effects was caused by an estrogen receptor (ER) antagonist as well as an aryl hydrocarbon receptor (AHR) antagonist and inhibitors of protein kinases A and C and mitogen-activated kinases. While an intermittent incubation with E2 caused no change in amplification of the glutamate-evoked GnRH release for 4 h, continuous incubation with E2 or o,p'-DDT caused an increase of this amplification after 3.5 h of incubation. In summary, DDT amplifies the glutamate-evoked GnRH secretion in vitro through rapid and slow effects involving ER, AHR, and AMPA receptor mediation. [less ▲]

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See detailMechanisms of larval cohort suppression and population fluctuation in tiger salamanders.
Whiteman, Howard; Wissinger, Scott; Denoël, Mathieu ULg

Conference (2006)

The mechanisms underlying population fluctuation have been well studied in mammals and insects but less research has focused on amphibians. Yet, the current global decline of amphibians requires that we ... [more ▼]

The mechanisms underlying population fluctuation have been well studied in mammals and insects but less research has focused on amphibians. Yet, the current global decline of amphibians requires that we understand these mechanisms, and be able to distinguish between anthropogenically induced declines and natural population fluctuations. We have followed a population of the Arizona tiger salamander, Ambystoma tigrinum nebulosum, over 16 years and through two cycles of population fluctuation, which is typified by the production of “boom” cohorts followed by suppression of larval recruitment by paedomorphic adults in this cohort. We tested two hypotheses for this suppression, cannibalism and resource depression, using a series of meso- and microcosm experiments. We found significant direct (mortality) and indirect (behavior, diet, growth rates) effects of cannibalism by larger larvae and paedomorphic adults on hatchling and 1st-year larvae, suggesting that both cannibalism and the threat of cannibalism play a large role in suppression of larval cohorts. In contrast, paedomorphic adults showed no substantial effects on larval survival, diet, or growth via resource depression, in part because paedomorphic adults reduced availability of large benthic invertebrates, while hatchlings fed primarily on smaller benthos and zooplankton. However, current experiments suggest that hatchlings can be impacted by cohorts of larvae that are more similar in size and diet. Our results lend insight into the mechanisms underlying fluctuations in this population, and suggest that a better understanding of natural population fluctuations will aid amphibian conservation efforts. [less ▲]

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See detailMechanisms of leukemogenesis induced by bovine leukemia virus: prospects for novel anti-retroviral therapies in human.
Gillet, Nicolas ULg; Florins, Arnaud-Francois ULg; Boxus, Mathieu ULg et al

in Retrovirology (2007), 4(1), 18

In 1871, the observation of yellowish nodules in the enlarged spleen of a cow was considered to be the first reported case of bovine leukemia. The etiological agent of this lymphoproliferative disease ... [more ▼]

In 1871, the observation of yellowish nodules in the enlarged spleen of a cow was considered to be the first reported case of bovine leukemia. The etiological agent of this lymphoproliferative disease, bovine leukemia virus (BLV), belongs to the deltaretrovirus genus which also includes the related human T-lymphotropic virus type 1 (HTLV-1). This review summarizes current knowledge of this viral system, which is important as a model for leukemogenesis. Recently, the BLV model has also cast light onto novel prospects for therapies of HTLV induced diseases, for which no satisfactory treatment exists so far. [less ▲]

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See detailMechanisms of Persistent Nf-Kappa B Activity in the Bronchi of an Animal Model of Asthma
Bureau, Fabrice ULg; Delhalle, Sylvie; Bonizzi, Giuseppina et al

in Journal of Immunology (2000), 165(10), 5822-5830

In most cells trans-activating NF-kappaB induces many inflammatory proteins as well as its own inhibitor, IkappaB-alpha, thus assuring a transient response upon stimulation. However, NF-kappaB-dependent ... [more ▼]

In most cells trans-activating NF-kappaB induces many inflammatory proteins as well as its own inhibitor, IkappaB-alpha, thus assuring a transient response upon stimulation. However, NF-kappaB-dependent inflammatory gene expression is persistent in asthmatic bronchi, even after allergen eviction. In the present report we used bronchial brushing samples (BBSs) from heaves-affected horses (a spontaneous model of asthma) to elucidate the mechanisms by which NF-kappaB activity is maintained in asthmatic airways. NF-kappaB activity was high in granulocytic and nongranulocytic BBS cells. However, NF-kappaB activity highly correlated to granulocyte percentage and was only abrogated after granulocytic death in cultured BBSs. Before granulocytic death, NF-kappaB activity was suppressed by simultaneous addition of neutralizing anti-IL-1beta and anti-TNF-alpha Abs to the medium of cultured BBSs. Surprisingly, IkappaB-beta, whose expression is not regulated by NF-kappaB, unlike IkappaB-alpha, was the most prominent NF-kappaB inhibitor found in BBSs. The amounts of IkappaB-beta were low in BBSs obtained from diseased horses, but drastically increased after addition of the neutralizing anti-IL-1beta and anti-TNF-alpha Abs. These results indicate that sustained NF-kappaB activation in asthmatic bronchi is driven by granulocytes and is mediated by IL-1beta and TNF-alpha. Moreover, an imbalance between high levels of IL-1beta- and TNF-alpha-mediated IkappaB-beta degradation and low levels of IkappaB-beta synthesis is likely to be the mechanism preventing NF-kappaB deactivation in asthmatic airways before granulocytic death. [less ▲]

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See detailMechanisms of photocatalysis in TiO2 thin films for air purification
Poelman, Dirk; Heinrichs, Benoît ULg

Report (2012)

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See detailMechanisms of reduced and compensatory growth.
Hornick, Jean-Luc ULg; Van Eenaeme, Christian ULg; Gerard, O. et al

in Domestic Animal Endocrinology (2000), 19(2), 121-32

Growth is an integrated process, resulting from the response of cells dependent on the endocrine status and nutrient availability. During feed restriction, the production and secretion of growth hormone ... [more ▼]

Growth is an integrated process, resulting from the response of cells dependent on the endocrine status and nutrient availability. During feed restriction, the production and secretion of growth hormone (GH) by the pituitary gland are enhanced, but the number of GH receptors decreases. Changes of GH binding proteins induce GH resistance and are followed by reduced insulin-like growth factor-I (IGF-I) secretion. On the other hand, high circulating levels of GH enhance the mobilization of fatty acids, which are used to support energy requirements. Thus, when feed restriction in growing animals is moderate, there is mainly protein but barely fat accretion. By contrast, a severe feed restriction enhances the release of catabolic hormones and stimulates, from muscle cells, the liberation of amino acids, which are used by hepatocytes for gluconeogenesis. During refeeding and compensatory growth, the secretion of insulin is sharply enhanced and plasma GH concentrations remain high. This situation probably allows more nutrients to be used for growth processes. The role of plasma IGF-I during compensatory growth is not clear and must be explained in connection with changes of its binding proteins. Thyroxin and 3,5,3'-triiodothyronine seem to have a permissive effect on growth. The simultaneous occurrence of puberty with refeeding can exert a synergistic effect on growth. Initially, compensatory growth is characterized by the deposition of very lean tissue, similar as during feed restriction. This lasts for some weeks. Then, protein synthesis decreases and high feed intake leads to increased fat deposition. [less ▲]

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See detailMechanisms of reduced implant stability in osteoporotic bone
Ruffoni, Davide ULg; Mueller, R.; van Lenthe, G. H.

in BIOMECHANICS AND MODELING IN MECHANOBIOLOGY (2012), 11(3-4), 313-323

The determining factors for the fixation of uncemented screws in bone are the bone-implant interface and the peri-implant bone. The goal of this work was to explore the role of the peri-implant bone ... [more ▼]

The determining factors for the fixation of uncemented screws in bone are the bone-implant interface and the peri-implant bone. The goal of this work was to explore the role of the peri-implant bone architecture on the mechanics of the bone-implant system. In particular, the specific aims of the study were to investigate: (i) the impact of the different architectural parameters, (ii) the effects of disorder, and (iii) the deformations in the peri-implant region. A three-dimensional beam lattice model to describe trabecular bone was developed. Various microstructural features of the lattice were varied in a systematic way. Implant pull-out tests were simulated, and the stiffness and strength of the bone-implant system were computed. The results indicated that the strongest decrease in pull-out strength was obtained by trabecular thinning, whereas pull-out stiffness was mostly affected by trabecular removal. These findings could be explained by investigating the peri-implant deformation field. For small implant displacements, a large amount of trabeculae in the peri-implant region were involved in the load transfer from implant to bone. Therefore, trabecular removal in this region had a strong negative effect on pull-out stiffness. Conversely, at higher displacements, deformations mainly localized in the trabeculae in contact with the implant; hence, thinning those trabeculae produced the strongest decrease in the strength of the system. Although idealized, the current approach is helpful for a mechanical understanding of the role played by peri-implant bone. [less ▲]

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See detailMechanisms of skin adherence and invasion by dermatophytes
Baldo, Aline ULg; Monod, M.; Mathy, Anne ULg et al

in Mycoses (2012), 55(3), 218-223

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See detailMechanisms of substance P-induced pulmonary oedema in the rabbit: interactions between parasympathetic and excitatory NANC nerves.
Delaunois, Annie ULg; Gustin, Pascal ULg; Ansay, Michel ULg

in Fundamental & Clinical Pharmacology (1995), 9(5), 450-7

The pharmacological mechanisms involved in the substance P (SP)-induced pulmonary oedema were studied in isolated perfused rabbit lungs. Substance P induced a dose-dependent increase in the capillary ... [more ▼]

The pharmacological mechanisms involved in the substance P (SP)-induced pulmonary oedema were studied in isolated perfused rabbit lungs. Substance P induced a dose-dependent increase in the capillary filtration coefficient (Kf,c), responsible for oedema. Atropine, hemicholinium-3 and ruthenium red pretreatment partly protected the lungs against SP effects, while tetrodotoxin and hexamethonium did not significantly modify them. (+/-)CP96,345, a NK1 receptor antagonist, completely inhibited the SP-induced increase in the Kf,c. Like SP, acetylcholine (ACh) and capsaicin also increased the Kf,c. Atropine and (+/-)CP96,345 completely blocked the oedema induced by both drugs. Tetrodotoxin and ruthenium red strongly inhibited the response to capsaicin and acetylcholine. It was concluded that SP-induced pulmonary oedema is in part mediated by a stimulating action on cholinergic efferent nerves, with subsequent release of endogenous acetylcholine. Acetylcholine can, in turn, stimulate the release of SP from excitatory non adrenergic, non cholinergic nerves. The effects induced by capsaicin and exogenous acetylcholine, thus endogenous SP, involve tetrodotoxin-sensitive mechanisms, while those produced by exogenous SP are tetrodotoxin-resistant. [less ▲]

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See detailMechanisms of the anti-obesity effects of oxytocin in diet-induced obese rats
Deblon, Nicolas; Veyrat-Durebex, Christelle; Bourgoin, Lucie et al

in PLoS ONE (2011), 6

Apart from its role during labor and lactation, oxytocin is involved in several other functions. Interestingly, oxytocin- and oxytocin receptor-deficient mice develop late-onset obesity with normal food ... [more ▼]

Apart from its role during labor and lactation, oxytocin is involved in several other functions. Interestingly, oxytocin- and oxytocin receptor-deficient mice develop late-onset obesity with normal food intake, suggesting that the hormone might exert a series of beneficial metabolic effects. This was recently confirmed by data showing that central oxytocin infusion causes weight loss in diet-induced obese mice. The aim of the present study was to unravel the mechanisms underlying such beneficial effects of oxytocin. Chronic central oxytocin infusion was carried out in high fat diet-induced obese rats. Its impact on body weight, lipid metabolism and insulin sensitivity was determined. We observed a dose-dependent decrease in body weight gain, increased adipose tissue lipolysis and fatty acid β-oxidation, as well as reduced glucose intolerance and insulin resistance. The additional observation that plasma oxytocin levels increased upon central infusion suggested that the hormone might affect adipose tissue metabolism by direct action. This was demonstrated using in vitro, ex vivo, as well as in vivo experiments. With regard to its mechanism of action in adipose tissue, oxytocin increased the expression of stearoyl-coenzyme A desaturase 1, as well as the tissue content of the phospholipid precursor, N-oleoyl-phosphatidylethanolamine , the biosynthetic precursor of the oleic acid-derived PPAR-alpha activator, oleoylethanolamide. Because PPAR-alpha regulates fatty acid β-oxidation, we hypothesized that this transcription factor might mediate the oxytocin effects. This was substantiated by the observation that, in contrast to its effects in wild-type mice, oxytocin infusion failed to induce weight loss and fat oxidation in PPAR-alpha-deficient animals. Altogether, these results suggest that oxytocin administration could represent a promising therapeutic approach for the treatment of human obesity and type 2 diabetes. [less ▲]

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See detailMechanisms of VEGF-A regulation by fully active MT1-MMP in Breast Cancer Cells
Sounni, Nor Eddine ULg

Conference (2003, April 25)

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See detailMechanisms responsible for ERBB2 gene overexpression in human breast and non-breast cancer cells. The role of AP-2 transcription factors - Review Article
Delacroix, Laurence; Vernimmen, Douglas; Begon, Dominique et al

in Cancer Therapy (2005), 3(issue B), 365-378

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See detailMechanisms underlying resistance to cetuximab in the HNSCC cell line: role of AKT inhibition in bypassing this resistance.
Rebucci, Magali; Peixoto, Paul ULg; Dewitte, Amelie et al

in International Journal of Oncology (2011), 38(1), 189-200

EGFR is frequently overexpressed in head and neck squamous cell cancer (HNSCC). Cetuximab is a monoclonal antibody designed to interact with EGFR, block its activation, reduce the downstream signaling ... [more ▼]

EGFR is frequently overexpressed in head and neck squamous cell cancer (HNSCC). Cetuximab is a monoclonal antibody designed to interact with EGFR, block its activation, reduce the downstream signaling pathways and induce EGFR internalization. This study aims to investigate the role of the EGFR signaling pathway and EGFR internalization in a cetuximab-resistant cell line and to propose a new therapeutic strategy to optimize treatment of HNSCC. The HNSCC cell line, CAL33 was sensitive to gefitinib but resistant to cetuximab. Cetuximab induces an unexpected EGFR phosphorylation in CAL33 cells similarly to EGF but this EGFR activation does not trigger EGFR internalization/degradation, the process currently implicated in the response to cetuximab. Cetuximab inhibits ERK and AKT phosphorylation in cetuximab-sensitive A431 cells, whereas the level of AKT phosphorylation is unmodified in cetuximab-resistant cells. Interestingly, CAL33 cells harbor a PIK3CA mutation. The treatment of CAL33 cells with PI3K inhibitor and cetuximab restores the inhibition of AKT phosphorylation and induces growth inhibition. Our results indicate that EGFR internalization is impaired by cetuximab treatment in CAL33 cells and that the AKT pathway is a central element in cetuximab resistance. The combination of cetuximab with a PI3K inhibitor could be a good therapeutic option in PIK3CA-mutated HNSCC. [less ▲]

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See detailMechanisms underlying the toxicity of lactone aroma compounds towards the producing yeast cells
Aguedo, Mario ULg; Beney, L.; Waché, Y. et al

in Journal of Applied Microbiology (2003), 94(2), 258-265

Aims: To study the fundamental mechanisms of toxicity of the fruity aroma compound γ-decalactone, that lead to alterations in cell viability during its biotechnological production by yeast cells; Yarrowia ... [more ▼]

Aims: To study the fundamental mechanisms of toxicity of the fruity aroma compound γ-decalactone, that lead to alterations in cell viability during its biotechnological production by yeast cells; Yarrowia lipolytica that is able to produce high amounts of this metabolite was used here as a model. Methods and Results: Lactone concentrations above 150 mg l-1 inhibited cell growth, depolarized the living cells and increased membrane fluidity. Infrared spectroscopic measurements revealed that the introduction of the lactone into model phospholipid bilayers, decreased the phase transition temperature. Moreover, the H+-ATPase activity in membrane preparations was strongly affected by the presence of the lactone. On the other hand, only a slight decrease in the intracellular pH occurred. Conclusions: We propose that the toxic effects of γ-decalactone on yeast may be initially linked to a strong interaction of the compound with cell membrane lipids and components. Significance and Impact of the Study: These findings may enable the elaboration of strategies to improve yeast cell viability during the process of lactones bioproduction. [less ▲]

See detailMechanisms underlying the toxicity of lactone aroma compounds towards Yarrowia lipolytica
Aguedo, Mario ULg; Waché, Y.; Beney, L. et al

Poster (2002, July)

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See detailMechanisms, causes, investigation, and management of vomiting disorders in cats: a literature review
Batchelor, Daniel J.; Devauchelle, Patrick; Elliott, Jonathan et al

in Journal of Feline Medicine and Surgery (2013), 15(4), 237-265

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See detailMechanisms, causes, investigation, and management of vomiting disorders in cats: a literature review
Batchelor, Daniel J.; Devauchelle, Patrick; Elliott, Jonathan et al

in Journal of Feline Medicine and Surgery (2013), 15(4), 237-265

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See detailA mechanistic basis for potent, glycoprotein B-directed gammaherpesvirus neutralization.
Glauser, Daniel L; Kratz, Anne*-Sophie; Gillet, Laurent ULg et al

in Journal of General Virology (The) (2011), 92(Pt 9), 2020-33

Glycoprotein B (gB) is a conserved, essential component of gammaherpes virions and so potentially vulnerable to neutralization. However, few good gB-specific neutralizing antibodies have been identified ... [more ▼]

Glycoprotein B (gB) is a conserved, essential component of gammaherpes virions and so potentially vulnerable to neutralization. However, few good gB-specific neutralizing antibodies have been identified. Here, we show that murid herpesvirus 4 is strongly neutralized by mAbs that recognize an epitope close to one of the gB fusion loops. Antibody binding did not stop gB interacting with its cellular ligands or initiating its fusion-associated conformation change, but did stop gB resolving stably to its post-fusion form, and so blocked membrane fusion to leave virions stranded in late endosomes. The conservation of gB makes this mechanism a possible general route to gammaherpesvirus neutralization. [less ▲]

Detailed reference viewed: 25 (5 ULg)